biomass downdraft gasifier

khí hóa biomassgasifier This handbook has been prepared by the Solar Energy Research Institute under the U.S. Department of Energy Solar Technical Iníormation Program. It is intended as a guỉde to the design, testing, operation, and manufacture of smallscale less than 200 kw (270 hp) gasiíiers. A great deal of the information will be useíul for all levels of biomass gasification

Acknovvledgments PERTYQP Since it is impossible for one or two authors to realistically comprehend a subject from all viewpoints, we have solicited input GOVERNMENT from leading workers in the field Early versions were sent to a number of investigators, and each was invited to comment on and supplement our effort We thereíore express our heartíelt thanks to the following reviewers for greatly enhancing the quality of the final product: Handbook of Biomạss Downdraft Gasi/ier Dr Thomas Milne, Solar Energy Research Institute Dr Thomas McGowan, Georgia Institute of Technology Mr Matthevv Mendis, World Bank Mr Bill Nostrand, New England Gasiíication Associates Engine Systems Dr Bjorn Kjellstrom, The Beijer Institute, Sweden Dr Hubert Stassen, Twente University, The Netherlands Prof Ibarra Cruz, University of Manila, The Philippines We take final responsibility for the contents and omissions, and extend our apologies to those vvorkers whose work we may have SERI/SP-271omitted -3022 ENERGY RESEARCH INS unknowingly DE880011 35 March 1988 ưc Category: TECHNICAL LIBRARY Organization and Use A gasiíier converts solid fuel to gaseous fuel A gasiíier system includes the gasiíication reactor itself, along with the auxiliary OCĩ 1988 OOtKNt COIORADO equipment necessary to handle the solids, gases, and804QI effluents going into or coming from the gasiíier The íigure below shows the major components of a gasifier system and the chapters in which they are discussed This handbook has been prepared by the Solar Energy Research Institute under the U.S Department of Energy Solar Technical Iníormation Program It is intended as a guỉde to the design, testing, operation, and manufacture of small-scale [less than 200 kw (270 hp)] gasiíiers A great deal of the information will be useíul for all levels of biomass gasification The handbook is meant to be a practical guide to gasiỉier systems, and a minimum amount of space is devoted to questions of more theoretical interest We apologize in advance for mixing English and Scientiíique Internationale (SI) units VVhenever possible, we have used SI units, with the corresponding English units fol- lowing in parentheses Unfortunately, many of the íigures use English units, and it would have been too difficult to convert all of these figures to both units We have sup- plied a conversion chart in the Appendix to make these conversions easier for the reader .Whole system Ch 9, 10 Mr Bill Nostrand, One of our very helpíul reviewers, died in May 1985 Bỉll was num- ber one in the ranks of those who became interested in gasiíỉcation because of its poten- tial for supplying clean, renewable energy We all will miss him The improvement of gasiíication systems will be noticeably slowed by his death.Notice This wasthis prepared as the an account of work of sponsored by who an agency of thegasifier United systems States government We report dedicate book to Bill Nostrands this world will bring to Neither the United States govern- ment nor any agency thereoí, nor any of their employees, makes any the level ofexpress safety, cleanliness, reliabilityany required realize or their full potential warranties, or implied, and or assumes legal to liability responsibility for the accuracy, completeness, or useíulness of any iníormation, apparatus, product, or process disclosed, or represents that its use would not iníiinge privately owned rights Reíerence herein to any speciíìc commercial Thanks, Bill product, process, or Service by trade name, trademark, manuíacturer, or otherwise does not necessarily constitute or and imply T B Reed A its Dasendorsement, recommendation, or íavoring by the United States govern- ment or any agency thereoí The views and opinions of authors expressed herein not necessarily State or Golden, Colorado reílect those of the United States government or any agency thereof Printed in the United States of America Available from: Superintendent of Documents U.S Government Printing Office VVashington, DC 20402 National Technical Information Service U.S Department of Commerce 5285 Port Royal Road Springfield, VA 22161 Price: Microfiche A01 Printed Copy AO A Product the for pricing all publications The code is determined by the number of pages in the Codes areofused publication Information pertaining to theEnergy pricing codes can be found in the current issue of the following Solar Technical Intormation Program Solar A Division of Midwest Research Institute publications vvhich are generally available in most libraries: Energy Research Abstracts (ERA); Research Institute for theand Technical Abstract Government Reports Announcements Scienti/ic 1617 Cole Boulévard, Golden, Colorado 80401-3393and Index (GRA and I);Operated Reports (STAR)\ and publica- tion NTIS-PR-360 available from NTIS at the aboveofaddress U.S Department Energy 11.9 Spark-Ignition Engine Conversion 107 51 7.1 Gas Testing regarded as on y emporary mod ca ons wara me Table 1-1 Summary of the Annual Potential ”Deve descr p on gas er fTechnology rucoron and 1000 seventies wr ers and workers nons heof econs d Un una e 51y W h in hIntroduction s11.8.1 n m nd FEMA rac ed wEnergy h Ha for LaFon ne 2.3manua Future opment Dofrect Engine System 107 use designs, songs continuous ofthe U.S Office Assess7.2 research group nThe producer gas (IGT1984) In add on ar c es oftoday’s n eresprocess and he proceed of en span cond ons However a few car makers wen so far as o of Existing Sources of Biomass in the United States opera mass ve on b (LaFon b ograph a ne es 1987) of und The fferen gas a f ed er ma has er passed a can of he B omass Energy Founda on o bu d a pro o ype Pred c ng he needs and d rec on of deve opmen n 11.8.2 Gas Mixers 107 development effort and lively open exchange should ment (OTA) recently has issued a report calling for 8.9 Disposal of Captured Contaminants .92 nd ec and D ec Gas ca on P ocesses 25a 13.4 Economics 125 exce en gas ca on work s proceed ng n Canada many years of research The E ec r c Power Research Chap er 7.3 er and 51 mod yGas-Quality he cou bodydMeasurements work for wgas fread er ns aRequirements a ab one par Soon use he reader or g ve an mpress on of a eve of he es and he manua s now n he process of be ng our modern wor d s very dangerous because we don’ gas be made h y ava s enable us to incorporate latter-day and national Braz capability for pp emergency of Europe he Ph nes New implementation Zea and and 108 o her Ins e 11.8.3 (EPRI) hasPower comm ss wo schemical udab es eon 8.8.1 Char-Ầsh 92 413.3.1 nd ec Time Py oLag c Gasava ca on 25 Costs af7.4 er ouDescription he ow-cos gaso neoned became agahe n unders and cond does ons no w ex s change for gasandcawha on 125 We know how uFEMA ure our pub shed byng and wrwar e 3a 1“cra sman of Producer Gas andQuads/Yea Itsclean, Contaminants 51 10® Dry chemical engineering techniques to build congasiíiers (OTA 1984] par s of he wor dD pr mar y a he un vers y eve 109 use of producer gas (M er 1983 Schroeder 1985) 11.8.4 Engine Startup 8.8.2 Tar H Current Deve opments Future rect 413.3.2 wen D ec 92 Gas ca on Calculating Energy Costs 125 and mos users back o burn ngstory gaso ne rbecause Tons/Year hope and h sw manua w ons he reader o pu h25s response be S nce hehe f rsp OPEC embargo n 1973 7.3.1 ThenGas Analysis 51 venient, and nreliable systems A recent vrorkshop on Governmen eres gas f ca on has ended o focus Crop residues 278.0 4.15 11.8.5 Ignition Timing 110 of 4s4conven ence P nc 8.8.3 p es o Ope Condensate 92 a on o D ec Gas e s ma have er a osc n o perspec 27 we a edPotential be ve ween a concern w h energy 126 sup13.3.3 Equipment Cost low-energy gasification tabulates research and 1.2 Biomass Energy 7.3.2e sys Particulates26.5 51 on arge-sca ems Animal manures 0.33 11.8.6 SparkPlugs 110 p es and bus ness as norma There ore we can’ 4 n oduc on 27 13.3.4 Conversion Efficiency and Fuel Consumption 127 development needs (Easterling 1985) Biomass is ch a renewable fuelare that ke supplies 2% towe 3% of 7.3.3 Tars 55 9.1 Unused Gasitìer 93 mill 24.1 0.41 11.10 Two-Cycle Engine Conversion 110can pred c wh d rec on we y o go bu Đooks B omass Systems ca on s perce ved by he ore gn a d gas 4 Ope a on o he ưpd a Gas e 27 13.3.5 The Cost of Operating Labor 127 Producer Gas R&D Fund ng residues The accelerated use of gasiíication technologies ulU.S energy needs and an even larger percentage residues 83.2 1.41 7.5 Sampling 55in93 a easwass a he poss b eofopresearch ons andandaccommerc ors 111 affec 11.11 Diesel Engine Conversion agenc esThe of he deve oped coun r es (sucha asGas he eU S 9.2Gas Complete Gasiíier 2.2Logging Current Deve Act vSystem There grea dea aOTA za413.3.6 opment Ope atheir on ot es he Downd 28 Maintenance Costs 127 timately depends upon ability to compete with some other countries (OTA 1980; DOE 1982) U S AID has had a s rong n eres n producergas echMunicipal solid 130.0 1.63 he cho ce 7.4.1 Sample Ports 55 Agency for In erna ona Deve opmen [U Swas AID]) as a thermal process isbuses combustion, which yields only heat 11.10.1 Diesel Operation with Producer Gas 111 on d rec ed oward coa and b omass gas ca on berucks cars and n Europe and probab y more 1.1H Role of Gasitỉcation in Điomass Conversion Af er he OPEC o embargo of 1973 here renewed 9.3 Storing, Feeding, and Sealing Solids 2.1 stor ca Deve opment wastes íossil fuels, 4torests 4Beneíits which in Facturn o s Con depends o ng on S unknown ab y 6.51 o Gas factors e Ope ano onogy because 2893 projects that biomass could supply from 7% to 20% (6oữers a means for reduc ng he deStanding 384.0 13.5 Cost 128 ma or po11.10.2 en a orms energy source forEngines many parud s of he Pyrolysis uses heat tode break down biomass and yields 7.4.2 Isokinetic Sampling 56 ween 1850 and 1950 Hovvever cheap and p en u gas In norma mes deve opmen s dr ven by economic han a m on wor dw (Eg off 1943) However hese Starting Diesel 112 n eres n a of a erna ve energy nc ng gas Cha coa Gas ca on about resources, and At 9.2.1 Characteristics of 93 17 quads*) (OTA 1980) sources as28 pendency ofannually deve optars, ng na ons onfrom mpor ed fuesuch s 128 and Totals 925.8 14.44 handbook explains how biomass be converted 13.4.1 Value ofPower Produced 1This Ear y wor Deve opment of Gas cat on deve op ngfrom deconomics, The Be er Inspolitical uSolids ecan ofconditions Sweden has charcoal, wood-oils, and gases and o preven ed he commerc a deve opmen of he considerations, and some of he econom c ac ors mpress ve numbers nc uded on y s x wood-fue ed 7.6 Physical Gas-Composition Testing 57 coa and b omass Mos of he ear y work 11.10.3 Throttling at Partial Load 113 aproduced present (1988), gasiíication and other alternative energy those shown in Table 1-1 (Reed 1981), if it can be made Summa y 29 has suppor ed a number of pro ec s around he wor d 9.2.2 Storage to a gas in a downdraft gasifier and gives details for Does not nc ude unused bark from wood pu p m s organ zed 13.4.2 wo nheerna ona erences hese donor Cogeneration Possibilities 129 echno excep n gas of emergency The s n- cAuenc use of on are ed n reader Chap ers93 veh esogy ninng he Un Round ed Smes a ab esca and wo n sCanada where Gasiíìcation processes convert biomass into combussuppor bytesting, ed S a es and for ore gn n United energy Raw Gas 57 Gas caed7.5.1 onare was dUn scovered ndependen y bo h processes being developed slowly in the available a convenient form and if conversion equip11.12 Increasing Power from Producer-Gas-Fueled Engines 113 The Producer Gas e of S ockho m Sweden designing, operating, and manuíacturing 9.2.3 Feeding Solids 94 Source: Reed agenc es and pub shed hree vo umes of recen s ud es re erred espec a y o a number of exce en h s or ca 13 In n es of emergency, our pr or es change ow-cos gaso ne nued o be ava ab e hroughou tible gases that ideally contain all the energy original13.6 Financing 129 es abt er shmen s of ocused on Gas arge-sca coa -fed gas ers France Gas Des gns and and n 1798 and by e1850 he echno 1981 p 39Eng States because relatively supplíes ofpower mentovers is accessible potential world 7.5.2 Cleaned an gh organThe za on supporofedbiomass by varforous n-30 11.11.1 Mechanisms ofPower Loss 11361 gasiíiers and gasiíìer systems, primarily for shaft of gas ca on re evan o Solid heplentiíul prob ems ofura deve oplownga 9.2.4 Sealing Flows books Modern Gas Prođucers (Rambush 1923) dras ca yMany and qu oc(Bioenergy desfferen opmen sgas occur he war ar were wr enpromo on fncaormaon94 ly present in the biomass In deve practice, gasiíĩcation can were n ended o produce syn he c na gas as ogy had been deve oped o he po n was pos13.5.1 Government Subsidies in the Form of Tax Incentives 129 cost gaseous and liquid íossil fuels However, political use is equally great 1985) erna ona deve opmen agenc es o e 2rChemical n11.11.2 oduc 30 generation 7.7 upe toGas 200 Composition kw ItBreathing is intended to help convert 61 Engine 113 coun es (K son rom 1983 1985) gSma ves accoun of exper ences w inhrap updra and coa dur ng an me (see Chap er 1)on Some of Fans, Blowers, Ejectors, convert 60% to were 90% ofgas theoped energy biomass into fue was epractical eres nform b omass or bof omass B s13.5.2 afrom renewab enenergy wa hfield many pos sgasiíication bomass e9.4oThere gh much London wart hCompressors manu ac ured gas orgas ers deve very dand yographs dur he95 changes could rapidly and and dramatically alter this on exchange on ca othe beng ween Financial Institutions 129 aofEfficiency into en7.6.1 Gas Samples for Chemical Analysis 61 11.11.3 and Power Loss 114 Bas c Gas e Types 30 gas ers Generator Gas (Gengas 1950) and s segas ers ed o veh c es of era are shown n F g energy in the gas Gasiiĩcation processes can be either gas ca on (PNL 1986] excep for groups concerned 9.3.1 Importance of Gas-Moving System Design ve ea ures The b omass eeds ock s of en a ow-cos “gineered own gas” from coa (S nger 1958 Kaupp 1984a) emergency of Wor d War II and us as rap d y d sap15 Sou h Afr ca s un que y s ua ed re a ve o producer situation, design as witnessed duringthe the handbook OPEC oil crises deve op ng coun r es I has sponsored wo ma or n-95 Although íocuses on *1 quad = 10 Btu 7.6.2 Methods of Analysis 62 que Wood Gas Generatorỷor Vehicìes (Nyga ds 2-1 Mos gas ers were s mp y “be ed on” and direct (using airqu ord oxỵgen through129 ex11.11.4 Blowers 114 w h513.7 uses nbecause ess deve oped coun rA es an (NAS Other Considerations byproduc of agr cusoon ure or sandvonly cu ure sechn n -ash Manu ured gas he cow ca o1983 hey peared when fue(K s were ava 1983 ab heat e 1985) Transpora on31 4ac Cha coa Gas e sas gas research s hcrossed gh y Superchargers deve oped 9.3.2 Fans ĩ 95 erna ona erences etos generate rom downdraft gasiíication the method suitable for 1979) g ve he prreader a comp eUeS coverage of aof othermic: reactions) or yindirect (transíerring heat to the 7.6.3 Water Vapor Analysis 65 K e s rom 1981 1983 1985) and pr va e nd v duá s su fur 11.11.5 en and Other Methods does no for ncrease Increasing he Producer eve of Gas Power 115 Un ed S a es and by 1920 mos Amer can owns and s a very h gh or and he Depar men and produces much of s fue by gas ca on However Blowers 96 small-scale power it also extensive detail 5 Cha9.3.3 coa ve systems, sus B omass Fue gives s 31 A e eve ofgas fund ng ($2 onbe oburned $5 m66 aspec s of downdraf ers dur ng d WarII Gas reactor from they outside) The gas can to(Skov Reterences 1974 her 1982 TIPI1986) 131 carbon dhas oxEngine de nLife ahe mosphere he subsequen 7.8 Analysis supp ed of gas Test Data opopu form cook and Demodera ense curren has a fprogram omWor d ssem na e 115 nforaesso aMo na vehe ares onden ofsand 20 onngwhose 11.13 and Engine Wear biomass fuels, gas testing and cleanup in9.3.4 Ejectors 96 on yr) has been ma n a ned s nce 1975 by DOE Producers and Bỉast Furnaces (Gumz 1950) ooks The C ossd a Gas e 32 produce industrial or residential heat, to run engines for greenhouse effec (prov ded consump on does no gh ngma hrough heMass oca “gasworks ”coun ma on 011 sma gas ers n case of na ona needs ch hose of ess deve oped rBalances esbwill A ma or 7.7.1 Balances and Energy 66 strumentation, 11.12.1 and safety Engine considerations LifehaExpectancy that be of 115 Recen y here has been ncreased n eres n omass as 9.3.5 Turbochargers and Superchargers 97 “advanced concep ” for gasand cak on and pyro s wood proaemergency he her- However modynam cs neor coanoys and mechanical or electrical power, toofmake synthetic Appendix 139 exceed annua produc on) Ca be n aken o1985 eneconom c cs reasons work on32 wor d7 erence nSticking mber u e mus za on May 5to The Upd aữwho Gas e use all those work with gasiíiers at whatever 7.7.2 Flow Rate Characterization 67 a renewab e energy source In he as few years a 11.12.2 Intake Valves 116 cesses Mos of he work s a med a arge ndus r a gas caon The ar c e by Sch ãpfer and Tob er In 1930 f rs na ura gas p on peh nerenewab was buecabason os fuels 9.5 and Product-Gas Burners sure haFlares bheomass use asons fue sbo awood gas f ers for veh c es s n progress n he Un ed S a es97 nc7.9 uded weekong sess on scale number of nd s oand have bu o gas verse ons of Particle-Size The mbev dua Downd a groups Gas erom 32 Measurement 67 11.12.3 Oil Thickening and Contamination 116 processes and sbiomass suppor abora orwell es “Theore ca Prac ed ca nmpor Sgovernmen ud es ofalready Opera of ranspor na Denver he ds 9.4.1 Flares 97 (Lowderm kura 1975gas Reed 1978) 1985) Today many coun r of es Durone ng sense, he a eand 197ŨS, we ed ismore han 40% of and charcoa manu ac ure (NTRI In gasiíication aon sma combustion downdraf gas ersParticle-Size and have opera edvery hem as The of biomass in wood stoves and in7.8.1 Typical n oduc on Distributions 67 32 ndus r a fữms and un vers es Progress n hese Mo orcars on Wood Gas ” (Sch ãpfer 1937) s he bes Texas As p pe nes cr sscrossed he coun ry ow11.12.4 Tar/Oil Accumulations 116 (such as Ch na Korea Braz and Sou h Afr ca) have our o We reserved rauch of our qu d fue for proven technology Approximately one million 9.4.2 Burners 98 demons undhas sDesc AcAnalysis gasgas f er-powered dustrial The European boilers increased Commun dramatically y (EEC) in shown sgasiíiers repor he mee ngs ofcaDOE’s Therprac ca and schere enedwas ữca dno scuss on of sma gas ers o cos na re ura sp aced manufac ured and he 7.8.2 on 7gas aEconom pfew on oof hehe Downd mbe 67 33 ac ve òres onSieve programs are he aphas ng osome n-Gas e programs 11.12.5 Engine Corrosion ranspor and governmen o deve 116 op downdraft were used to operate cars, trucks, veh c Instrumentation esand from effor are shown n F gnen and areas, acrease grea dea íorest, of hn sMicroscopic eres agricultural, ba omass and energy paper a2-2 orms areGas e mochem ca Convers rac ors in(PNL 1986) as99 appear dur per od despread soon was orgo “Town 10.1once-w and he wor dryn cControl ores area W h wastes nued gas n nghe Unelectric edon S aCon es (However Sweden-Vo vo 7.8.3 o3 a ndus Supe Ve Size oc Analysis y Hea Load and S z ngers 35 boats, trains, and generators Europe during 11.12.6 Engine Warranty 11767 oday one can ob a n shop p ans for cons ruc ng being and has used been extensively very ac ve for n fuels gas f by ca some on dur Industries ng he as we as a o her mee ngs DOE recen y sponsored a gas” nued o be used n Eng and un he 197ŨS, d 11.14 gence he prospec s for mak ng b omass ru y manu ac ured and s ored 10 000 un s for emergency Exhaust Emissions 117 World War II (Egloff 1943), and the history of this ex7.8.4 Aerodynamic Tu ndovvn Ra Size o Analysis 67 36 10.2 The Need for Instrumentation and Control 99 A more genera survey of b omass herma convers on gas ersp an (Nunn khoven 1984 Mo her 1982 Skov However, frenewab ve fhe years (CEC 1980 1982 biomass Br fo dgwa use still waits for oenerthe mee o exam ne in he Chapter po en a 2.and prob ems ow bu s were d ysman ed ow er ng1984 he d Bscovery e more wOther sextensive ead mprove use ) ng perience is outlined However, theofwar’s 11.15 Devices for Producer-Gas Power Generation 117 was pub shed dur ng 1979-80 n he SERI hree7.8.5 Graphic D sadvan Analysis ages o of he Size mbe Distribution Des gn 69 1974) Un or una e y no body of n orma on s ava 10.3hGasiíier Instruments 99 application gy Nor 1985) The ofo EEC improved has ocused conversion methods, h ghsuch aspec ass energy gas this ca on (Eas er ng 1985] bu s curren as y36 of Sea Today a few pon an he s are s ech opera ng end saw emergency measure abandoned, vo ume Survey of Biomass Gasiỷication (Reed In he pr va e sec or of he Un ed S a es dur ng he as 11.14.1 Gas Turbines 117 ab e o he p e her he a er-day hobby s s or he r The 7.8.6 S a ed Physical Downd Size a Gas Analysis e 70 38 gasiíication, of gas h rd ca10.2.1 on that (such match as oxygen biomass gas energy ca on) to processes bu has ocus ng on d rec quefac on of wood The s a us of Pressure Measurement 99 n he wor d 1.3 Gu de to Gas t catved on Ln terature inexpensive gasoline became available (Reed 1985b) 1981) Thhere s governmen workbeen subsequen y and was pub shed 10 years has a correspond ng deve deve opmen s8work nvo fu - me research oExamples evaofua se 11.14.2 Fuel Cells 117 currently acoun so erpar unded requiring n liquid sma and -sca gaseous e gas ers fuels as par n oduc on 38 many of he research opmen 10.2.2 Gas Flow Measurement 8.1 Gas Cleaning and Conditioning 71 commerc a gas y of biomass as forPrincipìes of disrupted Biomass of b omass ers heat applicaỉions a 100 he Development gasiíication was in cr such caved11.14.3 ac5processes ors such as f ero opera on gas qua y perce respons bes include y gas “assoc lime, a ed” and deve brick opExternal-Combustion Devices 11838 82 Desc poward on glass, he Sứa ed Downd a Gas epro ec s and commerc a gas ers pro ec s was sum1 1of B b10.2.3 ograph Solid Flow Measurement 103 Gasification (Reed 1981) The work Producer Gas: sca e found n umber and paper m s There has been 1946 as the war ended and inexpensive (150/gal) gas-c eanup sys ems eng neand opera on and eng ne Carré wear Introduction 71 manuíacture; ng8.2coun r5es power (Beenackers generation; van and transportation Swaa 1982 mar zed n Surveỵof Biomass GasiỊication (Reed of books Unansvve ons Abou a ed Downd The12.1 number ar c esed Ques and repor s on bheS omass Another Fuel for MotorThe 1983) n er-a esGas n epower genera onTransport a magnitude a sma (NAS sca n103 he40 10.2.4 Temperature Measurements gasoline became available of edamage Safe 1985 Br dgwa er 1984 NTRI 1985 Manurung and 1981) 2Biomass, Veh c e Gas t ers like coal, is a solid fuel and thus is inherent8.3 The Power Theory of Gas Cleanup 72 In eres n sma -sca e gas ers s s rong among orgas 10.4 ca Controls on y exceeds 1985b) w h e 8eas Mode ng10he000 S a (Reed ed Downd a Gas 42 exce en atechnology hed s or ve asbuy vveback as Un aednsSan a es s mu bycaa perspecrac inflicted on gasifier by ve thispower disruption can 103 Beenackers 1985) ty and Environmental 119 less convenient tome use the or liquid gan ons w of hthan essConsiderations deve coun rOne es fuels such many mpor an sdea ud es conduc edgaseous beoped ore 1950 can Sly ar abou he Wor d War I sma gas ers EPRI (Schroeder 1985) has eva ua ed he po en a of a pro ec on of Corn ng deve opmen s A monumen a es n some s a es under he Pub c U es 8.4 Gas Cleanup Goals 74 be seen by the fact that it is difficult for even the “ad5za 9ng Ta C ack ng Gas Ẽe s 10.3.1 Fuel-Level Controls An 10342 to which we become of as12.2 he Wor dhave Bank hecharcoa Uaccustomed S when Agency for Inoeeds erna ona eas ydeve become d scouraged ngoverfview ndocks he Introduction 119 oped around andCharacteristics bryomass gas forPo mak e ec c198ŨS y The Fores Serv cetests of work Gas Engine Regu ers aSmalỉ-Scale ory cyngAc (PURPA) d rto scussed nSystems, Chap er42 vanced” technology of therProduce achieve on 4were Commerc a ntormat on 8.3.1 Gas Contamìnant 74 n oduc on Pressure Controls 103 various processes now inysuse or evaluation for Deve opmen and he equ vansunder en organ zawork ons n ear erToxic works For una e much of h s ear y has o 12.3 opera e10.3.2 veh c es boa and sma e ec r c he USDA ho ds annua mee ngs a wh ch gas f ers are s ava ab e n he Un ed S a es and Germany (Kaupp 13 what was routine operation in the 1940s The design, Hazards 119 8.3.2 Dirty Gas 7443 5coun rofesTypical Combus on o Ta son Ano her source gas f er nforma s energy prov ded by converting biomass to more conventional forms 10.3.3 Temperature 104 European The Producer Gas Round ab e and (of been co ec ed some of has been summar genera ors (Rambush 1923) BeControls ween he wozed wor d dresearch, (FPRS 1983) 1984a) Inand addmanuíacturing onof odeve o her cons for dera onsdecade h s ers work teams of that have 12.2.1 Carbon Monoxide 119 A scussed very ac ve area opmen sma gas s 10.5 Computer Data Logging and Control 104 8.3.3 Gas Cleanup Goals 7445 compan es deve op ng commerc a gas er sys ems such as gas or liquid The fuels ma Ta is shown C ack ng in Fig 1-1 (Reed he Be er Ins u e n S ockho m) has pub shed a some of beenwas repr pursued n ed Wemos offery here an overwars deve has opmen by ama eur a ns ane n-dep rea men the of past he use of that oressmall and all disbanded We hhave from only o genera power n developing countries, 12.2.2 Creosote 121 Repor s on governmen programs are ma n a ned by he These groups wr Cleanup eshows adver ngsunlight brochures as 1978) The is to of books on on drawn oge 8.3.4 Design 7446 4body Ca agas y how csca Ta CTarget ack ng vnumber ew of of know edge nand order he p her he en husEngine as sh5 s9figure because gaso ne was re converted aasoveof y en nagr cu have ura res dues resources ữaction of Sc knowledge thatTechn has been published, wh ch ben omass and canno eason whereas y(OSTI) afford 11.1biomass Adaptation and Operation 10546 Off ce of c and ca In orma hey wr e sc en c ar c es and s some mes through either traditional activities (e.g., 10 Summa y echn ca exper se from around he wor d In add on 12.4 Fire Hazards 122 reader oca e requ red ma er a In genera he more expens ve and s mpoferParticles o use han b omass In 1939 he 8.5 Classification the large experience incro sbulk They doíirsthand noea have an ec d soperation r che bu 74 on where hey can of be ob ned n ee have herr campub or F qu na dyfue severa pr va groups shed or drecen ffs11.2 cu separa e ac ua ab from proranspor ec ed inper agriculture and or new novative h12.5 group has ed severa erences ono ormance producer Introduction 105 works arehos s sílviculture) ava e ocon German boockade ed a Europe design has been lost and íorgotten Environmental Hazards 123 gr d so power sys ems of 10 o 1000 kw are very 8.6 Particle Movement and Capture Mechanisms 74 techniques Gas t er Fabr cat on and Manutacture pr n ed cop es They are some mes d ff cu o ob a n48 repub shed gas f er p ans or gas er books and The r pub ca ons shou d be read cr ca y bu usua y (e.g., as energy plantations, coppicing, and gas 11.3 for ess oped coun rhees e papers s M ary use of ec gaso ne rece ved op prrom or 1981 yhave and1983 he Gas for Transportation 105 Two maProducer or deve co ons of o(K der been a er rac heve Thus he1986 scay eofof operas1974 onexhaus has aned mpor an Gasiíication was rediscovered in an era of fuel a or g na supp repor s Cop es pamph e s (TIPI Skov Mo her 1982 a n mpor an ( f op m s c) n orma on algaeculture) now being developed 1985) Collectors 7548 an Dry npopu oduc cmade v8.7 a on ons had The o U fend for ona hemse ves for 13.1 Decision Making he pas decade S Na Academy of n uence on s Nygards deve n and shortages andwha higher prices, there gasiíỉer 11.4nProducer Gas for Electric Povver and Irrigation 105 of hese repor s are aoil so oped ava1979) ab eh sncase GPO are depos ory Nunn khoven 1984 Biomass resources fall into two categories: wet or wetranspor fue s Approx ma e y one m on gas ers 8.6.1 Gravity Settling Chambers 7548 Sc ences pub shed a b b ography of s ex ens ve Ma e a s o Consữuc on gas from charcoa has been deve oped comengine under 20 brar countries for 5Producer Producer Gas Research 124 There are awayeas wo than suchmay es—one Fbrar na yesprojects new deve opmen s innmore gas ers ex end he r 11.5 Gasifier Types Suitable for Shaft-Power Generation 105 table biomass (molasses, starches, and manures) and dry were used on opera epapers veh cnes es wor dw de dur ngAnother hewhere war co ec on of ear y n Producer Gas: 8.6.2 Cyclone Separators 7548 merc a y he Ph pp (K e s rom 1983) producing process heat and electrical and mechanical pub c and one un vers y— n each State Me hods o Cons uc on use o o her new areas One of our au hors (Das) has 3 Gas t cat on Proceed ngs 13.2 Introduction 124 biomass Much research (woody o and aProducer r deve gasagricultural ca onEngine s be materials ng conduc eds years subsequen opmen of wood producer Fuel for Motor (NAS 1983) The 11.6The Sizing thenGas to the 105 more han 1000 un sTransport have opera ed Producer gasand 8.6.3 Baghouse Filter 80 power (Kjellstrom 1983, deve oped a fsma gas f er1985) su abIneyits fors rebirth, frepor r ng ed ahowever, oundry Curren gas ca on work genera a con-49 residues) aUn var ous Biological un vers es processes around he require wor d wet However biomass and s S z ng and Lay ng ou he P pes gas un s s a es o human ngenu y n he face 13.3 Logistics Assessment 124 vers y of Ca orn a a Dav s acqu red an ex ens ve genera ed for ndus r a hea by more han 30 arge un s the existing technology has uncovered major problems E ec os a c Co e P ec p a o s 83 11.7 Engine Selection 106 The o her au hor (Reed) s deve op ng sma ba chype ferences and hen appears n he pub shed proceedoperate dco ffadvers cu at oor near hroom s work temperature fs prepar occurr These ngprocese cher ses, unof Ex accoun ss make fasna ng 7in on ofrace papers wh e1984) ng State oỷthe 6ec ng ns sended and Con oApplication opera nyumen Braz (Makray 13.2.1 Gasifier 124 connection with effluent and gasapp cleanup and the fuel Federa Emergency Management gas ers for cook ng and gh ng caons n h rd49 8 We Sc ubbe s 84 11.6.1 Large-Vehicle Engines — Truck Engines up to 50 kw 106 ngs The U S Depar men of Energy (DOE) (PNL shown unded on on the a sma lower left e side The of hEngine Fig of 1-1, and include hs read ng or and nform hesca reader of work bo he Goss promSystems se and Artỷor Smaìì Gas Producer supply, which were less important during the emergency Agency (FEMA) Gas er Work Tempe a u e 13.2.2 Equipment Selection Factors 124 wor d coun 1982 Eas reresng 1985) he U S Depar men 106 of49 8gas 7of 1ehe P vers ncSou p ce es oof gas We Sc ubbe 84 Fd g ff 2 cu Veh cs ees sto a eUn OPEC NAS 1983 íermentation s(Kaupp uden a11.6.2 produce yEngines alcohols Ca orn and aaresadigestion sn deto Small us ng producer (Eg off 1941 1984a) Mos of hese papers aDav so 1943 he of World War II Today, these problems must be solved 67 5a2 2NAS Pon essu eEquSupply 13.2.3 Feedstock 124 Agr cu ure (USDA) Fores sProduc s Research produce serves methane menKaupp because has spanned aand decade Gengas 1950 1983 1984a) The downdraf gas erishe reached hasghes op8 11.6.3 Sc ubbe pmen 8649 Natural-Gas Engines 106 possessspec on of A aKaupp GATE n Germanỵ a so if biomass gasiíìcation to reemerge a fueldeve source Gas M x u e Soc e y (FPRS 13.2.4 Regulations 124 and nc udes bo h exper men a and heore ca s ud es men dur ng itheisemergency Worad few War years II FEMA has Thermal are he onbeg f8 11.6.4 e7nn processes íunction Aad very best using on biomass from 3angSERI yWar EquIIrecen pmen 8849 A ofAux Wor here pub was acagrea dea Diesel Engines Apparentlv, going to oftake for 106 the 1983 he U S Env ronmen a Pro ec on Agency (Goss 1979) Twen e Un vers y n he Ne her ands has Au oma c Con o s aken n eres n sma -sca e gas f ers because hey 13.2.5 Labor Needs 124 Cogeneration íeedstocks Indn11.8 aeres State with Report than on Biomass are of n o/Art a less forms of a50% emamoisture ve fue content sGasiỷication (Eg offand 1941 technology of the 198ŨS to be effectively applied to106 the49 (EPA) and he Ins u e of Gas Techno ogy (IGT) had a arge program n gas ca on for many years cou d unc on dur ng a per od of breakdown n our oain shown (Par khon 1985) the right side aFinal ns ofmore Fig 1-1 han The abs racwere s of Logistics 1943) By13.2.6 1943 90% of he veh cConsiderations es1200 nsimplest Sweden accomplishments of the 1940s Space-age advan- ces124 Chapter Introduction and Guide to the Literature and Research (Groeneve dgas 1980a bonBy Aarsen 1985 1985) ar c es on ca as he weend asofanBuekens assessmen ofThes powered gas ersenergy he warReed here1978) were Fig 1-1.by (Source: Un yBiomass of an F000 or da aenGa paths e has apower very ac v abvers y and exce snesv of more more han 700 wood-gas genera orshan ng ve have y had anuom ngc an eres n o var forms of supp due ackareoravailable her ous dfor srup on of raaterials and ocontrol systems gas ca on and have sponsored erences dea ng conven ona fue s F e gas pub ers be w g h2-1 h s Veh f e dc These ca ore ons1950 a(Source n many NAS 1983) Contents Contents vii V Handbook oof B omass Downdra Gas er Eng ne Sys ems H ory Curren s era andure Fu ure rec ons 73 n sroduc on and Deve Gu deopmen o he L andDResearch 2Handbook Handbook Downdraft Engine Systems 864Handbook o o B omass Downd a Gas Gas eGasitier Eng Sysne ems BBiomass omass Downdra erne Eng Sys ems vi viii v Handbook Handbook Handbookof oofBiomass BBiomass omass Downdraft Downd Downdraft a Gasitier Gas Gasiíier e Engine Eng Engine ne Systems Sys Systems ems Introduction and Guide to the Literature and Research Table 3-7.Standards Ultimate Analysis Data for Selected Pyrolysis Chars (Dryweight Basis,- VVeight Percent) MCW =depending (wet dry completeness weight)/wet weight (3-1) Table 3-1 ASTM for Proximate Table 3-8 Sultur ContentMethods of Biomass Fuels biomass, on the ofcan char gasiíication sents the maximum amount of energy that bePercent) ob- tained Table 3-6 Ultimate Analysis Data for Selected Solid Fuels and Biomass Materials (Dry Basis, Weight The ash content of biomass is typically much less than that such as that showninFig 3-4 (Reed 1978b) They make 3.4.1 Densifying Biomass Fuels 3-4.Analysis Approximate Moisture Material H N 3.2.2sThereĩore, Physical Tests As Referen c Higher Heating andTable Ultimate of Wood Feedstocks it is important to provide for adequate removal % Sulíur, Reterenc Sometimes, moisture content is reported on a dryweight from combusting the fuel and is a necessary value forof h ce of coals, but some forms have a high ash content, as shown in excellent gasifier fuels and allow the fuel to be stored at much Contents Typical Fuels Biomass fuels usuallyofhave bulkBiomass densities Test from oneehalf to Value (kJ/g) One ofMCD, the material most important physical characteristics of biomass Method No this bulky Dry Weight basis, where calculating the efficiency of gasiíỉcatioii The high heating Table 3-3 This cancoal lead as to shown ash melting (known “slagging”), densities Densiíication typically con- sumes only 1% Material Has presenting N a As Referen shigher obulk density Higher Heating one-tenth thatFuel of inc Table 3-11, (Btu/lb) Basis Biomass Retere fuel is the The bulk density is the weight of 0.1 0.1 Moisture Content Fir bark char 49.9 4.0 24.5 21 19.2 8,260 (1)some h ce Because charcoal often has a in high value, gasiũers are value measured in this test, since liquid water is Proximate Analysis which can cause severe problems ingasification some gasiíiers A to 2%(HHV) of theisweight energy contained the biomass; for MCD = (wet dry weight]/dry weight (3-2) Alfalfa seed straw 0.3 (1) nce Value (kJ/g) drawback for shipping, storage, and Biomass biomass packed loosely in a Container divided by (wt % Wet (wt % 2.6 0.1 6,100 sometimes operated to produce up to 10% charcoal by Rice hull char 36.0 0.4 11.7 49 14.2 (1) produced; however, the low heating value (LHV) is more Standard ASTM method is available for measuring the residues, drying may also require additional energy, but (Btu/lb) Moisture E871 Almond shells C0 + 0.7 H + (3.95 N ) (4-1) 2 20% of the original mass of carbon for conversion to gas It \ Gasifiers are relatively simple devices The mechanics of The resulting gas, called synthesis gas, can be used to fixed bed gasiíier, operation at lower values of (|) would CH / • Peat1979) 1979 conference no longer produce them (Reed an interpenetrating system, or block copolymer, that4-l(b), varies ina \ biomass; solid composition to the composition o in is Fig important in understanding pyrolysis, gasiíication, and initial dry weight of the larger is now recognized matter composed of their operation, such asaverage íeeding and gas also are manuíacture methanol, hydrogen, or ammonia There some cause charcoal be that produced (as shown for low (Ị) in 4Coal ■ Char 4.2.5There are Thermodynamics many types direct of Gasitication gasiíiers, each with itsbiomass special A The CO andco H inthe thevolatile hot char zone can react below where CH is conveyed anof íormula forcleanup, typical 2toíormed a is 4O 0 composition across the cell walĩ Nevertheless, inisFig large If the gas to be over a distance in a pipeline, mixture of and H , according to the íormula combustion According produce to the íigure, a íraction of char and ash size íeedstocks 15% to 25% charcoal monomers (as well as other fragments) of the cellulose, simple The successíul operation of gasifiers, however, is not interest in the Texaco to gasiíy biomass 4(c)), to andform it using would up in constant thesystem unless it isof augered virtues deíects will be discussed inshown Chapter 5.though 900°c methane according toreactor theBreeching reaction: (Actualand composition forofspeciíĩc biomass isenergy inchemical Tables sãmples, there is a build relativelv atomic ratio CHỊ Thermodynamics isThey bookkeeping of burned in No anyneat form ortothe used as system aAlremains the end Ifthe airexist isengine, allowed enter the after hemicellulose, and lignin polymer thatsealỉ make up consumes biomass so simple rules because thermodynamics of (Stevenson 1982] During updraữ or downdraft gasiíication, 10% to 20% of the C2H ,h or shaken out Operation at values of (Ị) above 0.25 4i^Liquid 20 in CHỊ O + 0.2 ũ -> CO + 0.7 H (4-2) 2 3-3, 3-4, 3-6, and 3-7) The nitrogen is shown parentheses thermodynamics cannot always predict what will happen for a OQ g (The ratios will vary slightly with species Coal is feedstock, the condensing tars will plug pipes sometimes in pyrolỵsis, the carbon (char) will burn, leaving the ash as the + 3also H2 —> CH + H2that up rapidly (Evans Ittheis recognized to 65% Hence, of(4-9) the gasiíier operation areas well understood Yet, nontrivial biomass will remain charcoal after pyrolysis istake complete charcoal1984) and CO because it isminutes an inert portion of out air and does not part ina ínot fuels about CH 9temperature O ! but variesgoes moreup widely in composiparticular process, itIn can rulecases, many things that cannot only aproduct few these ittemperature, isproduces necessary tosupply, use final Each form of biomass slightly dif4.4.4typically Factors Controlling stability ofto Gasiíier biomass dry vveight can be converted this vvater-soluble Uníortunately, there is more energy contained in the CO and thermodynamic principles dictate the air In an updraít gasifier, air entering at the grate initially burns maintaining the bed at a constant level automatically ensures the reaction combustion ofconverting biomass vvouldbe / of Biomass tion.) The reĩationship between unless solid, liquid, and gaseous happen It For was oxygen mentioned above that Eq.itthe (4-2) is This reaction proceeds catalyst mode of gasiíication that succeeds tarsash to íerent char, volatile material, “wood oil,” which potentially may form the is basis of new Operation H correct than is oxygen contained in slowly the biomass, sothere that thisa reaction and other ingheat variables theinreactors weand build It this charquantities tooperatliberate and C0of to that theofreaction: according the input \o.5 omitted / ^ Coals Ắ fuels is easily seen in Fìg 4-l(a) where the relative atomic thermodynamically impossible in the absence added heat gas This can be accomplished either by cracking (secondary present; however, it is quite exothermic and can supply heat if Knowledge of these quantities, as well as Iniet heođ (counterflow processes for wood liqueíaction (Roy 1983; Scott 1983; would require the transíer of energy from some external is a tribute to thecpersistence of experimentalists that so much + C0 + heat (4-6) o -> k}/g concentrations of carbon, hvdrogen, and oxygen are plotted and that Eq (4-3) actually governs the reaction How is this Ẩị Chars Solid Gasiíer operating temperature is a function of the amount of This combustion only) produces 20.9 (8990 Btu/lb) when ửie pyrolysis) or by partial oxidation in Aaming pyrolysis suitably catalyzed the temperature dependencies of the reaction and Gaseo Diebold source, which vvould greatly complicate the process progress has been made in the ofCombustion so little under4.4 Principles of Operation offace Direct 4.3 for Indirect and Direct Gasitication íuols a variety fuels Here it is seen thatThe the temperature solid íuels, determined? oxygen fed toof the gasiữer (Fig 4-4(a)) temperature of the losses, combustion products is low enough forany all us the associated weight are useíul in understanding gasiíier Almost immediately, or even simultaneouslỵ, the C0 X Products and 1984) Uníortunately, these oils are corrosive and highly > standing Nevertheless, it has been experience in related Concurrent with thecharcoal, emergence of biomass asleft an important Gasitiers ■*"fue Spírol tlights No.l biomass, coal and lie in the lower segment of In practice, some excess oxygen must then be added for Processes response, however, changes abruptly at an equivalence ratio the liquid to be water, and this is the value that would be operation and design \ H the present react with the char to produce the oxygenated, so that íurther Processing will be required to fields (such as the oil,gasiíier gas, and coal combustion) that once At highin temperature where gasiíication takes place energy source, it and wasgaseous natural that coal gasiíication ls the diagram; liquid hydrocarbon fuels lie the gasiíication (carrying the reaction to (ER) approximately 0.25 This change point, or in knee, measured in and a work bomb calorimeter and reported as ring fuel gases co H to qualitatively the 4.4.1The Introduction make of a Indirect high-grade liquid fuel (Diebold 1986) However, mechanisms results shown atriding in2 according Fig are 4-3 understood, are theonly engineer similar is to able those to (typically 700°-1000°C), there arefollowing areactions: few stable interpretations would be of carried over tosome explain biomass 4.3.1upper (Pyrolitic) Gasiíication Q left section; CO and H are joined bỵ the bisector of H the point o in Fig 4-l(b)), producing C0 and 600° 20 occurs for temperatures to 800°c (900-1100 K), the high heat of combustion or HHV as shown in Tables 3-6 they have been burned successíully in on in-biomass dustrial gasiíication boilers and obtained develop cleaner, in a proximate analysis most biomass Fortunately, but are much not combinations ofmore principal ofmake biomass— cthe + efficient C0 -) 2processes Cof oelements (4-7) Since volatile organic molecules up gasiíication Even today, mostProducts articles triangle; and the combustion ofvapor fuels,isproduces C0unstable according to It is now recognized that wood-oil and H 0, at depending on oxygen source Gasiíier pyrolysis oils and 4-1 In most practical2 combus- tion devices, the water turbines with (4-7) only and minor modiíications required for the identical of the knowledge because acheating quired in the these areoxygen higher íields can and besamples applied are to carbon, hydrogen, These are approximately 80% ofand products from biomass use only Eqs (4-8) toand ex- cracks plain biomass gasiíication Trunmon ond^rates lie on a vertical line on the right temperatures above 600°c rapidly at 700° to and tars that are stable for periods of second or more at escapes to the atmosphere as a gas, and the heat of C + H 0-»C0-+H (4-8) 2 4.4.3pyrolysis of the burners (Bowen 1982) roìl2Downdraft smaller enhance in our TGA (seethrust Chapter 3and gasííication processes c, co, Operation C0 , CH ,ofthe 0.L The relative CH 14O + 0.41978; ũ2 0.7Jasas CO + 0.3 C0 2Eq + 0.6 H +applies 0.1 H 20to(4-3) 2understanding 4, H Eq (Diebold 1985b), principal task biomass and (4-4), even though (4-4) the VH42Gasitier VIninSIthis s/ \ (but Drive 800°cignore to form hydrocarbon gases as gasiíiers methane, operate ethane, temperatures below 600°c Since (such updraít vaporization of theQssembly water is notkrecovered case, the Downdraft gasiíiers have been very ossembly Thermal conversion processes for biomass are indicated10% by concentration of these species that wĩll be reached Fuelhopper The first reaction is called the Boudouard reaction, and the CO COo not coal) gasification is to convert this condensible volatile 80% biomass volatiles Biomass pyrolysis produces only In chapter, weLHV, present a summary of the of underlying and ethylene), Hof co, and (temperatures C0 In addition, obtains a 1% below an aER 0.25 lessone than 600°C), lowthis heating value, , percent successíul for operating engines the amount low tar Typically of methane íormed as well 0.5 the arrowscharof few Fig 4-l(b) Here itcharcoal is seenare that the conversion at equilibrium can begases predicted from thebecause pressure, the second ispermanent called the water-gas reaction They have been matter to A secondary task is to convert the to 20% coal, and the is very reactive processes that occur biomass gasiíication We will to 5% yield of a tar composed of from polynuclear and considerable quantities of tars gas are emitted witharomatics theshown product 20.4content kj/g(a) (8770Most Btu/lb), be the maximum could be of would theduring work reported inheat thisthat book was (b) Typical properties of chemical producer biomass in processes move the tion ofare biomass to of each extensively element, and the equilibrium constant determined studied for the last 100 years in connection with resulting charcoal also to gas Thereíore, this cannot be found the composiprimary explanation for1979; the attempt to keep the explanation simple because each phenols similar to those in coal tar (Antal gas generated The difference between LHV and HHV is small for períormed on downdraft systems, and they will be the Table 4-2 liquid orgaseous solid fuel(b) regions, either bybiomass biological or thermal from the thermodynamic properties and subcoal biomass gasiíication, since thetemperature, principal product of conversion ofroll biomass to gas Fig 4-1.and (a) Phase shovving the relative proportìons of carbon, hydrogen, and ject oxygen liquid,Trunmon and íueìs Chemical changes during íundamental process is basically simple Chapter gives 1984; Diebold dryversion wood butdiagram increases rapidly moisture content of task thea in solid,Diebold The most important types of fixed-bed gasiíiers for5mine this principal gasifier discussed inthen thewith balance of book an processes Reed 1981) means In someof cases (such as the to energy balance It is possible tothis deterthe coal pyrolysis is(Source: coke (carbon) The rate of the reaction has In theassembly gasifier Fig 4-5(b), air oxygen/air is injected gasiíication), at the inter- face more extensive description of HHV the operation of speciíic 1985) wood (In the United States the isgasifiers normally for are thestudied updraít and downdraft of used Fig Table 4-2 Typical Properties of In the downdraft gasifier of Fig contacts the are spontaneous; in other cases (such as steam species that would form at equilibrium as disappearance a air íunction of 4-5 been by measuring the rate 4-5(b), of of 4.6 processes between the incoming biomass and the char If too much char Summary gasiíiers arebeavailable from the literature for those rating the Detailswill These discussed in greater detail Chapter Producer from must Biomass pyrolyzing beíore it to contacts theHchar and ports gasiíication) considerable energy be expended to of cause amount of biomass oxygen added the system The results of carbon,gasiíiers coal, or charcoal while passing C0in over the Pyrolytic gasiíication isaGas accomplished when a portion the is produced, thetask air of consumes excess char rather than or 2supIn summary, the gasiíierthe is threeíold: interested in aintroduction more thorough explanation (Reed 1982; Kaupp 5, but a brief here will facilitate understanding of acalculations flame similar to the flame that is generated by the match in the change of this type are shown in Figs 4-4 and 3-5 solid (Nandi 1985; Edrich 1985]” fuel or char is burned in an external vessel with air, and the biomass; if the char is consumed too fast, more biomass is Table 4-1 Properties of Typical Biomass Ridmg ring 0.00 biomass 0.20 0.40 0.60 volatile 0.80 matter, 1.00 1.20 1984a; ReedThermal 1985b)7 the íundamental principles involved • to pyrolyze to produce gas, and Fig 4-2 As in the case of the match, the heat from the resulting heat is used to supply the energy necessary to consumed Thus, the Imbert gasifier is self regulating At Intel seol— Equivalence Both of these reactions requireRatio heattemperature (i.e., they are enEquivalence Ratio The adiabatic reaction of carbon buming volatiles maintains the pyrolysis When this pyrolỵze the biomass The principal advantage of this SERI we have built the oxygen gasiíier shown in Fig 5-12 (b) Combustion Feed chute terms “updraít gasiíier” and “downdraft gasiíỉer” may 4.2 The Biomass Thermal Conversion dothermic anddetermined therefore cool the gas (a) with airreactions) biomass or oxygen, in this manner, is • to convert the volatile matter to the permanent gases, CO, Gas is Gas phenomenon occurs vvithin a gasiíier, supply process is this thatwith a amedium-energy gas We operate fixed flow of oxygen andproduced add Dry biomass seem mechanical descriptions of limited gas reacts flowair patterns about like 25°c every of temperature C0the These that that shown in trivial Fig for 4-4(a) This1% is the would be Processes H , and CH Compound Symbol (vol.%) (vól.%) in the gasiũer is rapidly consumed, so that the flame gets without using oxygen The higher energy íaster or the slower to tomaintain In practice, however, updraít gasiíiers can900°c, tolerate reactions very rapidly atbiomass temperatures to convert carbon co and H 2a fixed bed level In the reached if occur biomass came to equilibrium with theover speciíied richer as pyrolysis proceeds At the end some of ửie advantages pyrolysis zone, content may be required for pipelineofdelivery BuckRogers gasifier ofCO Fig.long-distance 5-11, 21.0 a fraction air is moisture feeds and thus have for Typical dry biomass tormula: 22.1 4.2.1high Introduction Carbon and amount ofash-free air orof oxygen is no These tasks are accomplished by partial oxidation or pyrolysis the gases consist mostly about of (moistureand [MAF] basis)inCHiaequal 4(There O parts The disadvantage that a signiíicant fraction of tar10.2 maythe be introduced throughis the rotating nozzles and maintains monoxide producing gas for combustion burner However, Carbon COo 9.7 guarantee that processes equilibrium will be reached insome any or given Thermal for biomass involve alla in various types of gasiíiers , Hconversion C0 co, and H 25% c We call this flame in dioxide 0, produced, and indirect heat or mass transfer is required, zone at that level (Walawender 1985) 4.2.2 Biomass Pyrolysis Hydrogen H2 14.5 15.2 updraft gasiíiers produce to 20% volatile tar-oils and H0 gasiíier, but downdraft gasifiers approach equilibrium quite of the following processes: —by limited supply “flaming pyrolysis,” distinguishing it Composition 52.2 4.3 41.7 which complicates apparatus and(lysis) the Pyrolytic so are -air unsuitable for operation of thus engines Downdraft VVater (v) is thethebreaking H2O 4.8process Pyrolysis down of avalues material closely see below.) Some gasiíiers operate at lower of (vveight %) from open wood ílames with unlimited access to air (Reed 1.6 Composition (mole 33.3 46.7 20.0 gasiíication will notbe discussed because it is1.7 only Methane ch Pyrolysis: Biomass + Heat —> oil, gas gasiíiers produce typically less thanCharcoal, 1% tar-oils and so are heat (pyro) It is theby first stepíurthor in the combustion or (Ị) on purpose augering charcoal out of the char %) widely 1983a) Flaming pyrolysis produces most ofreasons the combustible Nitrogen n 48.4 50.8 The oxygen used a process determines practical in oíbiomass large installations and is not as well-developed as in used for engine operation The for this gasiíication Whenbiomass is heated in the absence High Heating Value 20.9 kJ/g (8990 Gasifícation: Biomass +downdraft Limited oxygen — > Fuel gas zone in order to produce charcoal—a valuable bỵproduct— gases generated during gasiíication and the products and temperature of the reaction The direct gasiíication with oxygen or air Gas High Heating difference are given bẽlow Btu/lb) of air to about 350°c (pyrolysis), formsatcharand to yield the higher gas heating valueitshown low (|)coal in Value: Low Heating Value 20.4 (8770 simultaneously consumes 99% of thekJ/g is oxygen the principal oxygen consumed isBiomass typically astars the It equivalence Combustion: +plotted Stoichiometric* Generator gas (wet 5506 kJ/Nm (135.4 (chemical Symbol: C), gases (CO, C0 , H , H 0, CH ), and tar 2 4.3.2 Gasitication Fig 4-4[d] Such operation is not a true gasiíication but might Btu/lb) bDirect 4.4.2mechanism Operation of the Updratt Gasiíier gas downdraft gasiíiers basis) (with gas Btu/scf) ratio, (ị)for - the oxygen relative tìiat measured requiredin for Generator (dry 5800 kJ/Nm (142.5 The high heating value (HHV)combustion is used theinvalue that isto usually the —>generation Hot products vapors an approximate atomic makeup CH Obed ) be called “gas/charification.” In entrained or of fluidized b Pyrolysis and gasification processes are endothermic, so heat basis) Btu/scf) The isobtained shown schematically Fig.vvater 4-5(a) laboratory and gasiíier would during combustion ifinliquid was complete combustion (Complete of biomass with If theupdraft íormula for be biomass oil is oxidation taken as approximately Air Ratio Required for Gasitication: The tar vapors are gases at the temperature of pyrolysis but operation, the ratio of biomass to oxygen can be varied must be supplied in order for the processes to occur In fact, allowed to enters condense outa as a an liquid The lowFigs heating value (LHV) isthe obtained Biomass air seal (lock hopper) at top Fig 3-7 Direct-heat rotarythrough ơryer (Source: Perry 1973, 20-35, 20-36) oxygen requires vveight ratio of 1.476 [mass of Thermal processes have high throughputs and can, CHỊ partial combustion of these vapors can be 2.38 kg wood/kg air OQ , then typically condense to form a smoke composed of fine tar droplets as when water is produced as a vapor The high heating value of typical biomass independently In thistocase figure; 0.5usually CO +(Ị) 0.5 (4-4) + 0.4 H + 0.2 H air (Ib/lb) biomass (Reed 1984) This heat is supplied directly by combustion can be seen in the Aaming match of Fig 4-2 The thus reacts with to make co Hat and traction region whereformed M at is the theíraction middle; of moisture andrising combustion (wetC0 basis), Ais isHindicated the of byash, a ộand and > 1MAF 4.5 flame Charcoal Gasitication Cellulose isthe a 2reduction linear polymer of anhydroglucose units; partially combusting the volatile tars in downdraft gasiíiers; desígnates the moistureand ash-free basis The air/biomass ratio required for provides heat for pyrolysis, and the resulting gases and (The exact -to-vapor-ratio will depend These values are based on ashand moisture-free biomass with the Finally, below zone incoming air burns the absorbed in the endothermic reduction and pyrolysis reactions the right hemicellulose a(Ib/lb) mixture composition of polymers 5- andgasiíier total combustion 6.27 kg/kg The manuỉacture ofluminous charcoal forfrom use a sensible synthetic fuel dates composition given in Table 4-1.comes The wet-gas composition is the most important in updraft gasifiers, it the heat of the vapors burn in the ílame in as a process called ũaming on the isexact vapor and charcoal to isproduce C0 ofand heat above property of the gas for mass and and energy balances, butthe dry-gas composition The composition of the gas produced is shown in Fig 4back at least 10,000 years is closely associated with the The LHV can be related to the HHV and an analysis of the combustion gases resulting from charcoal gasiíication This combustion combustion After the flame passes a given point, the char conditions.) Downdraft gasiíiers usuallỵ produce (Desrosiers 1982; Reed 1985b) Notevapors that that the Depending upon the pyrolysis conditions in amoìsture gasiíier, one can is usually reporìed of the dittìculty ìn measuring heating Products as: 4(b) amount of oil/tar, energy remaining in development ofbecause our civilization Today, charcoal isThe used as then dilutes thecontinue product gas(some with matches C0 and may may not to the burn are are less The thanto 1% theheat reason behind combustion C0 is exothermic, and the produced in the condensible value ofor the a gas is usually calculated from gas composition, using 2a value of generate wide range of vapors (wood oil and wood tar) in Equivalence Ratio Equivalence Ratio HHV = LHV + F h m w to gas is shown in Fig the char and converted from solid the prime of heat for cooking in less developed source H 0, the products chemically treated to prevent the charcoal from smoulderíng) almost exclusive use of downdraft gasiíiers as an energy 13,400 kJ/Nm (330 Btu/scf) for H and co, and 41,900 kJ/Nm (1030 Btu/scf) for gas here is the hot gas If the pyrolysis products are to be burned where Fm is the vveight traction of moisture 4-4(c) The low heating value of the gas is shown in Fig 4countries also isisused for the reduction of many ores in methàne theandmatch (c) When extinguished, remaining wood source for operating engines produced in íigures the combustion200 gases, and hw is the heat of immediately heatforindowndraft a boiler for the drying 400 These are typicalfor values air or gasitiers, but they(close-coupled can vary between 4(d) Fromofthese it isBtu/lb) seen that at an equivalence ratio smelting processes vaporization water, 2283 J/g (980 continues to undergo residual pyrolysis, generating a visible (°C) Fig 4-4 (a) Abiabatic reaction temperature for biomass otatomiccomposition CHi 4O0.6Temperature reacting operation), with oxygen andair, plottedagainst the equivalence ratio, (ị),onthe ratio ables of oxygen togas that 4880 and 7320 kJ/Nm Btu/scf), depending varisuch as then the(120-180 presence of condensible vapors in the smoke composed ofvolume the condensed tar Source:for Modiíied data in 1981.gas composition for reactiorỉ with air (c) Energy in solid required completefrom combustion (b)Reed Equilibrium and gas (d)loss, Energy per ofgas (Source: 1981, Figs S-2 at-the S-5) gasitier heat biomass moisture content,Reed anddroplets char removal grate is of little importance In Fig 4-3 Thermogravimetric analysis of a typical biomass sample heated in the absence of air (Source: Reed 1981, Fig 5-2) Source: Moditied from data in Reed 1981 *“stoichiometric,” that quantity required for a complete chemical reaction fact, theCombustion condensible tars represent a high-energy and of combustion with of oxygen If the combustion fuel is ac4.2.3 Biomass since measure it canon beof used the as of a íeedstock producer gas forfrom the quality chemiApproximately cal synthesis through thermogravimetric analysis from gasiíier systems relative to those íossil fuel dependent the rate heating and size of the biomass Chapter Principles of Gasitication a a b Fig 4-2 Pyrolysis, gasitication, and combustion in the (laming match 24 Handbook of Biomass Downdraft Gasiíier 28 Gasitier Engine Systems 26 20 22Handbook HandbookofofBiomass BiomassDowndraft DowndraftGasitier GasitierEngine EngineSystems Systems Principles of Gasitication Gasiíication 25 Principles of 27 29 Principles of Gasiíication 23 Principles of Gasitication 21 OJ ring was qualitative inSizes nature, the authors haveleading had concalled the “Imbert” gasiíier (after its entreprenurial in-(Gengas ventor, units This term enables one to compare the períormance of hearth with unpyrolyzed biomass, to 5-4 of Zone for Different Fuel manuíacture wastes half of theTable energy inPrediction the 5.3Charcoal Gasitiers power vehicles, areTable largely self-purging.) Yet, it pyrolỵsis, iswood desirable to Length build ItUsually, is zone desirable to contains gasiíy more than 95% ofa the biomass, wood less than 1% ash However, tvvice the mass of oxygen required forData biomass and Intions both commercialization ofas 5-1 Maximum Reported and Hearth Load of Various Gasifiers T o Table 5-3 siderable experience in tar running this The interesting techỊacques Imbert) although itSizing was produced by Superticial dozens of Velocity a summary, wide variety ofunderstanding gasifiers on a and commonbasis Thesize maximum momentarilỵ high rates of production fuel also is 1950) On the other hand, Australia worked almost gasify ashigh muchchar of theconversion charb as possible before its packing the charcoal isdowndraft consumed, ìt eventually collapses to form a leaving Updraít only 5% charcoal char-ash gasiíiers were íirst to be Parameters SmallChips InchChips SavvdustCubesPeat hence increases the overall stratiíied gasifier have made the remarkable c d the e for —Gas +this Air/Oxygen companies undercharcoal otherBiomass names during World War II speciíic hearth loads for a number of gasiíìers are shown in nological antique Type D Vs Reterence very important proper operation Crossdraữ gasifiers have exclusively with during period because of that Bh Hearth Load Engine Maximum Povver increases the pressure drop Minimal char-ash removal can be powdered char-ash that may represent 2% to 10% of the developed for vehicle operation They are suitable onlỵ for CẼ oxygen/biomass ratio up to 10% ofDiameter the gasifiers biomass iswere removed progress in only a few years of but adata great deal Superticial Velíastest Approximately one Ifmillion of these mass Table 5-1 The table was calculated from available Peilets the time and thework, smallest thermal massofon of -using with cõuntry’s largeautomatically íorest acreage and small number of vehicles The ability toresponse remove variable amounts of char a shows moving accomplished byoxygen/fuel pressure-sensing total biomass, in as turn contain10% to with 50% ash Ash low-tar fuels such charcoal anding coke Figure 5-4 an 5.7.2 Description of the Downdraft (Imbert) as char-ashReíractory atCylinder the grate, the ratio decreases; effort still is in progress It is not clear whether this design Number Cylind Gasolin Proximate Analysis: (Dry Basis) produced during Worldthen War II, at a Genẹrato cost of about $1000 U.S gasiíĩers that have been thoroughly tested and lists the any gas producers because there is a minimum inventory of m ft m/s ft/s m /cm -h MBtu/í^-h grate adds a second design issue to the stratiíied downdraft Gasitier Inputs switches that activate the removal mechanism only when ^Drying contents depend on theconvenchar content the updraít charcoal gasiíier that was usedofinImbert thewood earlv and part the of oftheeach Dimensi eroftoZone rrealize that Gas eand Gasitier inNevertheless, turn temperatures of ílaming combustion decrease, theis simplicity charcoal gasification has will displace and Zone 803 90 65 (1983) It important the cost of 90ultimately maximum superíĩcial and heating load reported Note hot charcoal In one velocity design, a tional downdraft gasiíĩer could be 0begins to § gasiíier Char consumes more than Cylinde ons, vólum pressure Needed Operati degree of agitation The greater the degree of char reduction, World War II Air enters the updraft gasiíier from below the Imbert l-A 0.15 0.5 2.50 8.2 0.90 4.76 (Gengas 1950) the resultingmany gas has both a higher energy content and a charcoal higher attracted investigators, and more thanprimarily 2000 Char 10 35 producing such a unit today woulđ depend on the 10other that in gasiíiers European literature, hearth load startup is reported in gas Reíerring to 188 5-1 andscheme 5-2, the upper cylindrical part of Cast-iron operated in aFigs crossdraít during in order to rs mm e, at 2300 on, the smaller the resulting andthethe higher ash, asa grate and flows upwardparticles through.01 bed to the produce 110x 136 5.17 50 80 tarsystems content This added control of the oxygen/biomass ratio have been manufactured in the Philippines A large l-A 0.30 1.0 0.63 2.1 0.23 1.19 (Gengas 1950) Ash 01 009 05 constriction degree to which it could be mass produced since none of the volume units; in the United States, it is reported in energy the inner chamber is simply a magazine for the wood chips or Distillation minimize the startup time (Kaupp 1984a) 5.1has Introduction ° o(Kadyszewski oFw Biomass ( 0.955.8.4 in Fig 3-3.the The downdraft gasifier startup combustible gas (Kaupp 1984a) High at theand air Modeling stratỉíied Water not 20 shown 027 05 temperatures 25 number are well-defined not 6cbeen 110 X136 7.75 75ring1.01986).130 Biomass l-Aworking 0.30 3.1 0.34 (Graham 1983) Zone components arecurrently inherently expensive units biomass other fuel During1.81 operation, this chamber is tuel o °BF o D are CHi O0 6=0.402designs of gasifiers Many different have been built and response time is intermediate between the fast crossdraỀ inlet can easily cause slagging or destruction of the grate, and Downdraft Gasiíier Corp Fuel Properties: issue 110x 136 10.34 100 180 l-A 0.61 0.24 0.8 0.09 0.45 (Graham 1983) ° stratified o o2.0 íilled every few hours as required The tố 5.6 The Updraft Gasitier Adescribed third in the design of the downdraft gasiíier In Gertemtor Gas (Gengas 1950) a maximum hearth load in can the beextensive literature on this (see and steam the slow gasiíier often some or updraít C0 is added to the inlet air to moderate Air gasifiers operated either p by íorcing airsubject through the 40Agasifier Density g/cm 40 5.5isSERI The Crossdratt Gasitier ò 0.28 mathematical model has2opened been developed atthe SERI to 1.10 predict 3for Air/ox S-A 0.15 0.5 0.9 0.10 0.53 1982) spring-loaded cover is to1.00 charge(Reed gasiíier, and The updraft gasiíier has been the principal gasiíier the prevention of1950; bridging and channeling High-grade (B[ lmax ) value for an Imbert-style gasiíier is about 0.9used /hNote: At(pressurized) a heavy load, 170 mm cross section should be instead of 150 mm especially Gengas Skov 1974; Foley 1983; Kjellstrom the grate temperature Charcoal updraft gasiíiers fuel or by drawing the airused through the fuel 20the oNm are Bulk Density g/cm 15 50 45 The Imbert gasiíier requires a low-moisture ( raw gas ofL gasiíier and -0 ,L 3performance Physical -4 whether the gas can be cleaned 0.002-Composition determines Above 5000 a _ r Tarcontent 1300mg/m3 1300ppm -30 „ >Mercury mg/Nm -3 tars, the gas is difficult to clean C up1 and is suitable 0.00001-3 Particulate 330 mg/m 330 ppm 0.001-T* only for close coupled direct com- bustion Gas cleanup f- 0.0005 Ash content of particulate 30 mg/m 0.023 equipment should reduce the tar level to -below 10 mg/Nm 0.000005 ^ 30 ppm • Quantity and size of particulates: The nature and quantitỵ of -0.0001 H2O 7.1 wt% 71,000 ppm char-ash and soot entrained in the gas stream can help to Fig.6-1 Piping flow chart (Source: Adapted from Perry 1973, Fig 5-27) Chemical Composition • design tiltcrs Particles larger than 10 |iin be removed z must 0.00005 CO 0.0119 Vol% X 322 Btu/scf = 61 to a level below 10 mg/Nm for engine applications l ‘4 CO2 14 Vol% X • Water content of gas: The vvater content of the gas helps to 0.000001^ H 17 Vol Btu/scf = 55 calculatc cooling requirements -Vol%%XX 325 CH4 1031 Btu/scf= 20 L N 48 Vol % X _ _ _ -0.00001 136 0.005" b Dry Gas (HHV) 136 Btu/scf (60°F, 30 in Hg Dry) Nm of gas vveighs about kg, so that mg/Nm = ppm The gas heating value may be F G 01 2 r - Ui L a 3 b 50 Handbook of Biomass Downdraft Gasitier Engine Systems Gas Testing 51 The desiccant Container should be sealed for transport sample containers are unavailable, gas samples can and be weighing Raw-gas moisture measurement is essential mass collected in glass bottles by water displacement, insert-to ing a balance calculations stopper while the bottle is submerged and sealing by dipping the stoppered openingisinmeasured paraffin.(Fig Whichever is Finally, where volume 7- 12(a) Container and used, the samples should be tested as soon as possible, since ), means must be provided to pull a known quantity of gas hydrogenthiscan rapidly diffuse through rubberment seals and through train Hand-held positive displacevacuum stopcocks, thereby changing the gas composition in a few pumps are made by a number of sup- pliers (e.g., Mine Saíety, hours and Gelman) We have also used a hand-held rubber Draeger, 7.6.2 Methods of Analysis 7.6.2.1 Gas Chromatography p Gas chromatography (GC) is the most widely used method ofo gas analysis It depends on the ability of cer- tain adsorbent< materials to selectively slow the rate of gas passage through a column packed with the adsor- bent Hydrogen is slovved least, co, N , and are aspirator bulb and found ứiat 70 strokes collected L of gas (0.1 ft ) We also have used a Dwyer smoke test pump The gas meter is required only for initiallỵ calibrating the sampling train and pump, since counting strokes yields adequate precision for measuring the test-gas volume A decision on the amount of gas to be sampĩed should be based on the anticipated impurities in the gas and the con- taminant sample quantity required for the speciíic analysis methods available For instance, 50% grey scale analysis requires a 0.5 mg sample on a 47 mm íilter disc VVeighed samples require a to 30 mg sample size for analytical balances with 0.1 mg readability 7.5.2 Cleaned Gas Fig 7-13 Gas sample corttainers (Source: Strauss 1975, p 13 © 1975 Used with If the gas is cleaned sufficiently for engine use, it will be Tw (usually necessary to pass a much largerTo sample m ] through the íỉlter A mechanical pump capable of pulling a moderate vacuum, such as: a motor-driven vacuum pump or a H|isjB’ ^BT~!BỊ The ^ ỊJ=| calibrated air-sample pump, recommended positivedisplacement meter can also be located in the collection trainFine J V if the system pressure is between the pump and the gas1return close to atmospheric Gas pressure It is imperative to protect the pump and meter with a large absolute íilter because any tar or particulates entering the pump or meter will rapidly affect their períormance Dry bulb Desiccant and wet bulb 7.6Chemical Gas Composition thermometer 7.6.1 Gas Samples for Chemical Analysis b Continuous Readout Sampling Train The gas composition can be measured either con- tinuously (on-line) or through discrete samples taken periodically from the gas stream These methods will be discussed separately Beíore the gas is analyzed, it must be drawn from the system and cleansed of tar and particulate contaminants, as described previously Batch-sampling requires collecting a sample of gas in a suitable Container (e.g., glass cylinder, metal cylinder, Tedlar gas sample bag or syringe), as shown in Fig 7-13 The subsequent analysis is only as good as the sample, and it is easy for gas leaks to spoil a sample after it has been taken Thereíore, it is important to use extra care to avoid leaks either into the sampling train while the sample is being taken or out of the sample bulb beíòre the analysis is made (b) permission ol Pergamon Press) When possible, the sample cylinder should be evacuated or, alternatively, should be very thoroughlỵ Aushed The cylinder shouldbe filled to at least a small positive pressure from the filter Burner pumpGassampleFlowmeter (Fig 7-14), so that air cannot leak in beíore analysis A positive pressure sample can be collected without a pump by chilling the>■< cylinder beíore the gas is taken, so that a positive pres- sure develops as the gas in Readout the cỵlinder warms to room temperature Gas samples should be drawn from a point as close as practical ^^ to the gasiíier outlet, in order to avoid errors due to air leaks in the gasiíier piping Usually, any oxygen found in the gas can be attributed to air leaks, since oxygen is completely removed in the gasiíier forWhen Gasoxygen Quality andinMoisture is found the gas, the (clean composi-gas tion can be only) converted to an “air-free” basis by subtract- ing the oxygen and the corresponding ratio of niừogen (the N /0 ratio in air is 79/21) Some gas sample containers are shown in Fig 7-13 A rubber septum is a desirable feature that permits one to extract the gas sample with a hypodermic syringe for inịection into a gas-chromatograph without opening the stopcocks The hypodermic syringe for injecting samples into the gas chromatograph should have a valve at the needle that can be closed between íilling the syringe and analysis Valved syringes are available as accessories from gas chromatograph manuíacturers The metal cylinder of Fig 7-13 can contain gas at a much higher pressure than the glass system It is im- portant to use leakproof valves rather than needle valves on this Container and to avoid stopcock grease, which has a high hydrogen solubility A syringe also can be used to collect a gas sample If Standard gas Fig 7-14 Apparatus fordrawing gas samples: (a) Filling sample containers byliquiddisplacement; (b) hand-operaledpiston vacuum pump; (c) motor- driven rotarỳ vacuum pump; (d) rubber bulb hẩnd aspìrator; (e) Chapman tiíter pump (Source: (à, d, e) ASME 1969, Figs and 7) Fig 7-12 Sampling train coníigurations 62 Handbook of Biomass Downdraft Gasitier Engine Systems 60 Handbook of Biomass Downdraft Gasifier Engine Systems Gas Testing 61 The Orsat analysis depends on the ability of certain chemicals The most common GC detector períorms ato peak quantity with of that then determined by slowed to a greater and water andthe C0 arethermal slowed to react The selectively eachgas gasis component of the analyses by extent, measuring integrating the area under the peak in the curve and compared the greatest degree The gas sample is mixed with a carrier producer gas mixture The components conductivity of the gas (TC detector) and is the with a calibration known composition More gas; helium is used because it With does this not tỵpe occur are that ab-in sorbed in gas theof order of C0 most usually, suitable for producer gas measurement of , , co, advanced automati- cally controlled naturally in the sample A detector, which is inserted into the then H recorders and CHinclude detector, helium (or a hydrogen-helium mixture, see below) is , and the analysis reports the volume valving, integration of the response gas the end of of the records on athermal chart percent of each component directly curves, calculation of gas oftenstream used at because its column, abnormally high quantity from calibration fac- tors, and a printout of the recorder both the time of passage and the quantity of each conductivity relative to other gases Orsat analysis equipment is portable, does not require AC composition results Such a printout is shown in Fig 7-15 component The presence of a particular gas component is power, has no warmup time, and can be purchased (along with The flame-ionization detector (FID) measures the num- ber of indicated by the required chemicals] from scientiíic supply houses for ions produced in a ílame and is particularly use- ful for $500 to $1000 detecting hydrocarbon species The FID is not particularly useíul for producer gas, I- since producer gas contains few 7.6.2.3 On-Line Gas Measurement hydrocarbons other than-methane It is convenient to have continuous “on-line” measure- ment rả of all the gas components to show instantaneous changes in The response of the TC detector to low levels of hydrogen in composition that otherwise would not be shown by batch the inert carrier gas is nonlinear, and this leads to ambiguous sampling Methods for on-line gas analysis include flame results There are two effective solutions to this problem A observation, combustion calorimetry, inírared absorption, heated palladium tube at the inlet can be used to selectively thermal conductivity, and mass spectrometry diffuse the hydrogen out of the sample into a separate nitrogen gas stream; in this secondary stream, hydrogen yields The heat content of the gas is a measure of a gasifier’s a linear response (Carle method) performance and can be calculated from the gas com- position Alternatively, adding hydrogen to the helium (see Fig 7-1 and Table 7-2) Most gasiíier facilities, if they carrier gas will move the baseline onto the linear region of the have gas analysis equipment, use an Orsat analyzer or a gas TC-detector response curve chromatograph, so that normal- ly a value is available only after a considerable time delay (10-30 min) It is desirable to The position of a peak on the time scale of the recorder chart have a continuous indication of gas quality indicates the time of retention and is characteris- tic of each particular gas component The area under the peak, obtained by analog or digital integration, in- dicates the volume of each gas present Although retention times and sensitivities are listed for each adsorbent material, aging and drift are common to column pack- ings, so it is necessary to calibrate the instrument daily to obtain an accuracy on the order of 1% For this pur- pose, it is necessary to have a cylinder of previously analyzed Standard gas These cylinders are available from GC equipment manuíacturers Although samples are usually collected as needed, it is possible to use automatic sampling with the GC to give a measurement of gas composition at regular intervals The GC analysis cycle time depends on both the reten- tion time of the columns used and the number Continuous immediate readout of producer gas com- position, however, has been achieved intwo ways One method, used at u c Davis, uses inírared (IR) absorp- tion for continuous co, C0 , and CH analysis with a thermal conductivity detector for continuous H deter- mination The second method uses a mass specữometer to give immediate on-line digital readout of all gases present, co, C0 , H , , H 0, CH , and high hydrocarbons (Graboski 1986) The calorimeter shown in Fig 7-16 is a precise primary Standard for measuring HHV of the gas Combustion air, fuel rates, delivery temperatures, and pressures are careíully measured Heat-transfer air is also metered for inlet flow, temperature, and pressure A of species analyzed This time is typically 30 minutes, but counterflow heat exchanger cools the combustion products to [HP] 27:is oneMANUALINƠECTION AT 15:49 FEB 7, 1984 noie that the warmup time for the GC day the air inlet temperature (60°F) and simultaneously conRUN E7 SAMPLE W6 denses water vapor to a liquid The temperature rise of the A number of companies, including Carle, Hewlett- Packard, heat-transfer air is directly proportional to the HHV of the and Perkin-Elmer, manuíacture satisíactory units for $3000 to RUN TIME AMOUNT NAME fuel gas The equipment pictured in Fig 7-16 was designed $30,000 and provide excellent insửuction and Service 2.87 25.723 HYDROGE for gas with a HHV of 1000 Btu/scf and may require N 4.25 0.15of PROPYLENE modification the burner to use producer gas with a HHV of 7.6.2.2 Orsat Gas Analysis 9.46 0.08219 TRANSBUTE 150 Btu/scf The Orsat gas analysis system was developed to measure NE 15.26 14.592 C02 the gases C0 , co, , H , and CH It was Other simpler, more relative methods are available and may 1.318 the principal measurement15.84 method used beíore the GC was be sufficient forETHYLENE manỵ applications It is informa- tive simply 0.136 ETHANE developed in the 1950s and16.37 is more reliable and less costly to observe the gas flame during operation 17.09it requires more than GC; hovvever, time (typi- cally 30 18.41 minutes of full operator attention per analysis) and more skill.18.76 19.58 23.92 0.367 ACETYLENE Flame length tends to increase with the gas heating value; 0.49 OXYGEN flame luminance increases with hydrocarbon and tar content 1.949 NITROGEN After the operator has gained 3.9303 METHANE 0.002827 BACKFLUSH Fig 7-15 Typical gas chromatography printout 64 Handbook of Biomass Downdraft Gasitier Engine Systems Gas Testing 63 0J cu t o _ adequate capacity for prolonged use and adequate efficiency Table 7-7 Mass Balance u-> Q o hhoỵ o IỌ LỌ for equipment protection o Inputs %'S- CO (M ò cô (kg/h) Outputs (kg/h) Closure (%) CvJ h- 7C\J ọ o 00 Water Vapor Analysis Wet Chips Dry Airr^ Total Dry7.6.3 Gas Cha Tar H20 Total co H20 r can0.09 co OJ Water vapor be determined by many methods 98.9 The three 98 32.0 43.1 0.5 75.6 66.3 0.9 7.4 74.7 gig ư> LO 0.5 most suited to 0.14 producer gas condenser cọ LỌ ƠỊ are psychrometry, 910 32.0 45.2 77.7 68.0 0.9 7.4 76.4 98.3 0,5 co cộand gravimetric 1methods 920 35.7 62.1 CM 0.4 98.2 92.9 outlet temperature, 1.4 0.09 7.1 101.5 96.6 I< o'-' cọ 101 52.4 76.9 LO 0.8 130.1 116.97.6.3.1 1.7Psychrometry 0.09 13.3 132.0 98.6 « £74.0 ễ * cọ 1.0 929 52.7 127.7 113.0 1.8 0.14 12.2 127.1 99.5 cọ ẵ ® ® h- 0.5 be determined measuring the95.4 wet- and 106 58.1 76.8 135.4 117.0Water content 1.2 can 0.09 10.8 by129.1 _ơ) I I as in196.8 dry-bulb temperature of the19.7 gas Fig 7-17 The97.3 moisture ầ 112.1 * > io 111 89.1 1.0 202.2 173.8 3.0 0.27 00 cọ 9111 ơ) 0.7 is then calculated from a psychromeửic (Fig 796.2 237.3 218.9content2.5 0.18 22.9 244.5 chart97.0 ®140.4 g _ r-Ô 122 140.5 202.1 ư) 1.1 343.7 302.1 4.1 0.54 43.3 350.0 98.2 18 or 7-19, depending on gas temperature) to find the ócô CD moisture as absolute humidity co Source: Walawender 1985, p 918 Cỏ cô co cọ LO LÔ Moisture wt % = Absolute ọr^ humidity X 100 (7-3) casionally to gasiíier development coincide with the peak efficiency curve Engine ap- plications Csĩ ò 00 maximum cọ hearth load to coincide vvith cô and expense of measuring all flow streams Detailed mass and should be sized for 9.3 cvi cp cp ^íCM energy balances usually5*0 can be percô íormed at universities in peak of the efficiency curve in o )< order to allovv maximum room cõ chemical engineering Xlaboratories or at major research for turndown GÔ cô cvi laboratories, and only a few have c\i been períormed on air ló gasiíiers If gasiíica- tion is to become Ẽ C\ necessary to períorm mass and energy balances co distribution Knowledge of theinsize and other charac- teristics J ổ> accumulation of gas contaminants, so preíiltration should be Ờ5 s >.3p Adapted from ASHRAE Củ ÒS Fíg 7-18 Psychrometric chan for mediumO temperatures Fig 7-20 Tarversusflowforricehullgasifier (Source: Kaupp 1984b, FÍg 10-88) o c(Source: temperature, c used as in Fig 7-12(b) of òì |l £ T— 1981) cã cô J Ờ5 o o ơ) 05 1— cô 1— Gas Testing Testing67 65 Gas 66 Handbook68 of Biomass Gasitier Engine Systems côDowndraft Handbook of Biomass Downdraft Gasitier Engine Systems ‘T— ò 60 _3 diameter d c o > Theo solid particles that pass through a cyclone can be o expected to have a mean particle diameter near the bì 55 < 1) cyclones, gravity separators, and all Stokes’ law particle The cumulative particle-size distribution shown in Fig 7-4 movement plots as a straight line on probability paper, thereby indicating log normal distribution about a mean particle diameter, dp at 50%, with a geometric 7.8.6 Physical Size Analysis The major methods for particle-size measurement are shown inTable 7-9 Screeningand microscopy areused to determine linear dimensions The Stokes’ radius, r g) is the radius of a Ợ hypothetical spherical particle with the same íalling velocity ( and bulk density as the particle The aerodynamic diameter, D cỊpa, is the diameter of a hypothetical sphere of densrty g/cm that will attain the same íalling velocity as the particle E in question cố The number mass and area distributions all have the 5.5 same õ geometric Standard deviation, ơg o ữ? Á by the Scrubber períormance can be characterized similarly c size particle diameter which is captured at o50% The 5.0 preciseness of the size cutoff point is characterized C ”5 by the value of ơ„ Various scrubbers and separatorsDare compared in Tabìe 8-1 for cut diameter and sharpness INote Ó how many D _ those that have a Standard deviation near 2.5 Consider 4.5 o have a sharper orbroader deviation and why & > ơ) c O ) X 50 4.0 3.5L Producer gas flow rate,m /h (25°c,1atm) Fig 7-21 Flow rate effects on efficiency, heating vaiue, and gas composition for rice hulls (Source: Compiled from Kaupp 1984b data) Table 7-9 Examples of Size-Analysis Methods and Equipment General Method Particle Size, |im Examples of Speciíic Instruments* 37 and larger Dry-sieve analysis Tyler Ro-Tap, Alpine Jet sieve 10 and larger Wet-sieve analysis Buckbee-Mears sieves 1-100 Optical microscope Microscope Zeiss, Bausch & Lomb, Nikon microscopes with scanner and counter Dry Millipore 0.2-20 Royco IIMC system Light scattering Brink, Anderson, Casella, Lundgren impactors Cascade impactor M.S.A.-VVhitby analyzer Wet centriíugal sedimentation 0.01-10 Ultracentriíuge Transmission electron Goetz aerosol spectrometer Phillips, RCA, Hitachi, Zeiss, Metropolitan-Vickers, Siemens microscopes Reist & Burgess system microscope Scanning electron *This table gives examples of specitic equipment It is not intended to be acomplete listing, nor is it intended to be an endorsementoí any instrument Source: Perry 1973, Table 20-33 70 Handbook of Biomass Downdraft Gasitier Engine Systems Gas Testing 69 Chapter Gas Cleaning and Conditioning 8.1Introduction If the gas is to be used in a burner application, an updraít gasiíier can be used, and no cleanup will be needed However, if the fuel gas will be fed to an engine, then a downdraft or other tar cracking gasiíier must be used; and the gas must be cleaned and conditioned before it is fed to the engine The gas emerging from a downdraft gasifier is usually hot and laden with dust, containing up to 1% tars and particulates If these materials are not removed proper- ly, they can cause maintenance, repair, and reliability problems much more costly and troublesome than operation of the gasifier itselí In fact, it is likely that more gasiíier engine systems have íailed because of im- proper cleanup systems than for any other cause In particular, the gas is very dirty during startup and should be burned at the gasiíier until the system is fully operational (See Sections 9.3.3, 9.3.4 and 9.4.1 for blowers, ejectors, and ílares.) In 1983, the Minneapolis Moline Engine Company be- came the first contemporary engine manufacturer to offer a 5000-h warranty on its engine—based on a fuel gas at the engine containing less than mg/Nm of total combined tars and particulates (Mahin, June 1983) This amounts to 99% removal of all dust particles Prior to 1950, manuíactured gas was widely disừibuted to homes, and the technology for gas cleanup was used extensively and well understood at that time The chemical and energy industries of today routinely use the methods that will be described in this chapter In order to design effective gas cleanup systems, one must determine the magnitude, T > 700 °c T > 300°c T>80°c respective capabilities and suitability, and some approaches for overall cleanup systems The basic cleanup system design strategy should be based on the required cleanliness goals (determined by the application), the order of removal, temperature, and the intended deposit site for collected materials In addition, size, weight, cost, reliability, the need for ex- otic materials, water consumption, effluents disposal, the time between cleaning cycles, and the ease of equipment servicing must be considered The íìrst step toward producing clean gas is to choose a gasiíier design that minimizes production of tars and particulates to be removed, such as a downdraft or other lowtar gasifier, and to make sure that the gasifier is operated in a manner that will minimize particulate production by proper sizing (see Chapter 5) Develop- ment of cleaner gasiíiers is proceeding in the United States and Europe at a good pace (see Chapter 5) The next step, which simpliíies the handling of cap- tured contaminants, is to remove particulates, tars, and water in the proper order and at the right temperature If the gas is immediately cooled and quenched in one operation, then char, tars, and water all are removed at one location to form a stickỵ, tarry mess If particulates are removed íirst at a temperature above the dewpoint of the tars (~300°C), tars are removed next at intermediate temperatures (above 100°C), and water is removed last at 30°-60°C, then each separated con- taminant can be handled much more easily The rela- tion between gas temperature and each operation is shown in Fig 8-1 The final step of effective gas cleanup is to O co r~- O c\ l < CŨ Fig 8-1 Schematic relationship oígas temperature to contaminant removal Gas Cleaning and Conditioning 71 BA-G0201774 of99.9 Particle Collection Methods capture element is during the dynamic that and íorms the íilter ash that otherwise was present inTable condensate orSharpness scrub can water gasiíier, especially idling, wet fuel The details, including the mathematics, of8-1 separation be 8.6.2 sharpness indicates that particle separation is degraded by cyclone Cyclone inlet width bSeparators for astartup, given pressure dropwhen asonshovvn in 8.6.2.1 Cyclone Operating Principles o // ocake captured The pressure drop across the cleanup sỵstem 8.2The Povver Theory ofconsists Gas Cleanup surface This which of captured The íabric filter issuch noimparts doubt the mostitmotion efficient for fine Sharpness Size found in rises Strauss (1975) However, is ing to note Cut is used some mechanism reentrainment orinterestfragmentation Fig 8-6 Notice that of the effect of temperature 99.5 Cyclones are cake, simple and inexpensive dustReíerence and particles, droplet A cyclone separator a rotary todevice the gases and steadily with theasaccumulation of captured materials, Ak ! ° According to the contact-power theory of gas cleanup (Perry Separation Standard rCL ỵ// presents a circuitous path that effectively captures fine cleaning; but for wood gas, extensive precautions against that the relation between any separator’s 50% capture cutDiameter thereby enhances theorsettling rate to many pressure times thatdrops induced they are widely used on gasiíiers and will be The requiring minimum írequent particle automatic size and typical cleaning or replacement are 8.3.4 oseparators; 98 Cleanup Design Target 1973), for a given power consumption, as measured by the Deviation g = dp84/dp50 particles, while coarser captured particles maintain an open condensation of tar or water are necessary (Gengas 1950) (dpso) um particle diameter and the capture rate for other sized particles by gravity alone A cyclone separator is essentially a discussed in extra detail in this section o" shown for efficiency various scrubbers in aTable The filter scrubber Collection is low for clean,8-2 in-line but gas drop water flow rate,gas devices give Requirements for solid-particle removal may be determined cakepressure structure to or promote high permeability xall cleaning is: Note Table 8-3 that cylinder wear less for gravitational separator that has pressure been a »tion -V selection parameters arethe the particle size istoenhanced be removed, the climbsin steadily with the increasing drop as producer theby iìlter 0Hot 90 gas substantially the same collecefficiency, and cyclone separators are well suited to remove solid ,.^y from knowledge of average particle diameter dp, and the When a new íilter íabric is inserted, the main Gravity Settling 50of 2.5 Perry 1973 gas withcollection aplugged íabric íilter than forand diesel oil alone centrifugal íorce component The cyclone separator grade desired eữiciency, the maximum pressure drop becomes Collection efficiency measurements indp50 (1/2) dp 0Chamber (1/3) rìp90 = (1/4) dp (8ữ> collection efficiency increases with power Some particles larger than 10 |im as a preỉilter for the gas cooler and worst-case char-ash dust content (c This iníormation can mechanism *—1 of 1 particle collection d ).increasing is physical sizing as 'õ efficiency curve, Fig 8-4, applies to all loading cyclone as line filters should clearly indicate effects or 4) be During operation, the previously described íilterseparators, cake1grows Single Cyclone 2.5 Kaupp1984 improvement over conlimitations can be ỈỄ70 fine particleusing removal, astact-power shown intheory Fig 8-3, forto acollect vehicle be gathered isokinetic sampling techniques a determined by the openings in the weave At first, small 8.3Gas Cleanup Goals well as toinover inertial andcleaning gravitational collectors averaged ausing full cycle in order toclimbs, be meaningíul steadily thickness, collection efficiency and All collectors the same capture mechanism will the be Dgasiíier gained using designs for reduced power consumption that ofmay the 1939-1945 era.parrepresentative sample of all ticle sizes If ca represents paiticlesby pass uncaptured until some buildup dmax accumulates Das1986 Cascade Cyclones n in series 0.67* 1.8 ^50 pressureGas drop by across the filter rises When the has characterized the same slope (Fig 8-2) and íìlter Standard 8.3.1Cyclone Contaminant Characteristics períormance of particle cut cake diameter use small parallel streams, multiple in series, the maximum permisdust formust engine use,diffusion, thenpass the on the íilter From thissible point on, level thestages gas effectively identical n thickness =such isnasrated =cyclone ninremoval, =terms 4separators, 0.53* 0.65 separators are also used widely in industrial Off-line devices, wet scrubbers, 2Cyclone 30 transíer, reached optimal for the íỉlter cake must be deviation (Table 8-1) or cut size The cut size, dp Q, is the particle size which is mass or condensation maximum permissible dust penetration a is given by: through a packed bed of micrometer-sized particles Gas goals should be based on the degreematerials of con0.48* oprocesses > The 0.55 principles are well-developed, and designs are and cleanup electrostatic captured removed by one ofprecipitators, the followingdeposit methods: momentary flow captured 50% Interception and and impaction then emerge as of significant tamination, the flow size, path distribution, and nature of the the The períormance sharpness of size separation various easily scaled to the necessary size High-eữiciency cyclone ® ^dmax * 100 ^^dmeasured (8-3) outside of the These devices separate reversal collapse the bag and dislodge the cake as shown in 8.6toDry Collectors collection mechanisms contaminants, as well as the degree of cleanliness required The relationship particle cut gas diameters forcreate this type cleanup components are compared in Table 8-1 and Fig 8-2 separators can be íabricated readily by a sheet-metal or contaminants intobetween one stream and the into another stream Fig 8-10, a pulse jet of compressed or air to the On a probability plot of the size distribution of the dust 0.12.5 10 by the equipment Both solid and cies liquid contaminants are separator is bag given by (8-4), where dp is particle Particle cut diameter (as vvritten dp or dp ) is the particle Disintegrator 0.6these Perry 1973 vvelding shop Cyclone design parameters are presented in C 50 The pressure drops andEq eữicienassociated with 8.6.1 Gravity Settling Õ.6.3.3 Application of Baghouse Filters momentary collapse, orChambers dismantling andthe manually shown, for example, in Fig 7-4, we then find the par- ticle present in producer gas and Thesubscript solids are char, ash, and soot, Particle size, /um diameter and the numerical denotes the collection diameter at which 50% of particles are captured A capture this section and at greater length in Perry (1973), Calvert devices are predictable independent of the amount of shaking the bag (Breag 1982) size dp where cumulative mass % less than As long as1unlimited space and materials are provided, a Baghouse 1.3 fiIters have been used with Karbate in.a size Ap Perry 1973 and they cover wide range of sizes Thebuildup liquid isofinitially a efficiency of thatchamber particle rate other than 50% may beisUníortunately, noted as a cyclone different subscript A (1972), and Strauss the successíul small cyclones captured materials, eliminating the is slow pressure dp equals a Tnis(1975) dp 50 many then the cut diameter gravity settling theoretically can achieve any level of good success in of the more and After cleaning, the íilter efficiency lower until the filter o Cyclone-cloth (loaded) fine mist or fog composed of droplets smaller than Ị m, convenient relationship exists for particle collectors with 2.4 2.5 Perry 1973 required for small gasiíiers are not available commercially, so drop with use Off-line methods are applications Wire Mesh layers in required for solids cleanup.systems (Breag particle separation to(0.011 theuse Stokes’ limit of in about |im In reliable engine gasifier 1982; Kjellstrom cake reíorms It isdown wise to a preíerable conservatively 8.6.2.2 Cyclone Design Principles □ Cyclone-cloth (partially but the agglomerate to increase in size asdesigned the gas Standard deviation 2.5 Particles with diameters that the are they must be custom designed andhas fabricated 2.5 wire) 3droplets layers where they can be used gasworks used gigantic 1.5 loaded) fact, many of the earliest settling 1981) The use of fabric íilters virtually eliminated íabric íilter (5-10 cfm/ft ), or even larger bag area, to The cools.proportions for high-efficiency cyclone separators are A useíul ruleA of Cyclone-cloth thumb is that the cut(clean) diameter (dp 50 ) required double chambers However, evendeep though is effective, method corrosive maximize the interval between cleaningsthis so 2.3 as to Packed Bed in 1/2itbag shown in Fig 8-5 for a cyclone or scrubber will be about thePerry same 1973 as the • 1.65 Cyclone-alone be a+bitSaddles cumbersome maintain clean gas flow Fig 8-9 to Wet cyclone (Source: Calvert 1972, Fig 3.1-6) Spheres Velocity 0.95 1.8 8.3.2tends Typical Dirty Gas diameter at the cumulative íraction cor- responding to the The particle size that can be separated with 50% ef- íiciency fpsare Velocity fps Fig 8-11 Fractional efficiency curves o1 cyclone-alone and cyclone- cioth collectors Bag íilters suitable 30 only for gas removing dry100 particulates; maximum permissible penetration (Calvert 1972) A typical speciíication dirty be mg/Nm of is predicted for generalfor cyclones andmight for the high-efficiency (Source: Gas temperature (°C)Peterson 1965, p 48) sticky or tacky materials not release from filterbags particulates with mean diameter dp = 100 |im, a geometric 50 Collecting enữained cyclone proportions of Fig 8-6 bydroplets from wet Therefore, special provisions precautions areversus required to Venturideviation Scrubber in and ApWG 0.3 1.8 low-temperature operations Perry 1973 8-8 contamination Gas viscosity temperature Standard ơg 40 =a 3.5, andFig tar of 1000 scrubbers with cyclone separator requires an outlet are limited toof re- quiring 8.4 íilters Classitication Particles the maintain bag íiltnr temperature in order to prevent water dpc = V H b/[27C N Vj (p P )] (8-5) G e p G mg/Nm 0.625 gas cooling Calvert skirt to prevent reentrainment ofHole liquids that have impinged accurately controlled Various íilters were Sieve Platefrom 1.5 in ApWG Solid particles with diameters greater than 1cloth |im are called vapor Eq or tars condensing onthetherelationship íilter bag In partỉcular, 1972 From (8-5) we can derive between the on the outlet tube, as shown in Fig 8-9 used on gasiíiers between 1939 and 1945, but these proved to Velocity Vh = 75 fps density 0.2 (200 kg/m ), that the cyclone cut size will dust, removal and Also, those any tars with in the diameters gas stream must below still be since tar-laden start-up gasGoals should not be drawn through a 8.3.3cyclone Gas Cleanup separator’s particle cut size dp 50 and the be a continual source of difficulty because they could catch be ỊÌ.IĨ1 aie reíerred to as fume Liquid droplets over 10 removed by other means Kaupp cold bagRecent filter, the designDevelopment outlet Impingement Scrubber 4should locate the flare1.5 8.6.2.6 Cyclone 6.7 too hot, or would get wet (from fire if diameter they became The solids can be quite abrasive, and the tar mist can cause |i.m in are called spray, and droplets 1984a with dỉameters mbar/stage upstream from the bag versus íilter and provide means for1965, preheating 0.076 8.5 Fig 8-7 Particle settling velocity size and ơensity (Source: ASME Fig 6) Recent work has been done on cyclone design d A/ -n = inlet valves, rings, throttle shaíts, and other moving parts condensate) if are theycalled became tooAerosols cold Polyester felt or bags, the the 1the Stage below 10 |j,m mist are solids liquids 0.015 20 bag filter assembly c speciíically applied to gasiíiers by thoroughly LePori P stick V 2N e Vj (pp - PQ) 71 most widely available, are rated for 135°c continuous Service to Therefore, both contaminants must be 2(1983) Stage that have been used for bag íilters include natural suspended in a gas (Calvert 1972) Materials 8-6 High-efficiency cyclone engine — cut size inlet width 1950; Freeth 8.6.2.5 other Factors temperature Stainlessin Cyclone Steel, Pertormance glass-íiber, and for tion (Gengas ạ?Fig reliable = 63cyclone m3 opera3versus 3removed Stage 30 Nm /h 273 10 K /h (37 ft /min) (8-6) Table 8-4 Filter Fabric Characteristics A pipe 2.5 cm (1 in.) inside diameter should provide a gas organic fiber, glass1984a; fiber, ceramic íiber, and roand Dispersion aerosols are v The most common errors encountered inmaterials cyclone are ceramic-fiber bag filters have design been that useda 1939;synửietic Goldman 1939; Kaupp Kjellstrom 1981) 9(255 X 10~ kg/m-s)(0.025 m) velocity of Fabric Baghouse Filter 1.8 Peterson Steel The properties of these materials are outlined 3** gas begin as large particles and subsequently are broken into low intake velocity caused by an oversized cỵclone, and Operating Air 8.6.3stainless Filter successfully at higher temperatures and show good promise Successíul gasifier-engine systems have required 2(5)(14 m/s](2000 0.489 kg/m ) (3.14) 1965 quate solids-conveying velocity within the pipe onTable cyclone cut size is bag minimal This Permeabilỉty is due to the bTypi- cal in 8-4 Organic-fiber smaller sizes They tend to be coarse with a wide size-range, reentrainment of solid particles caused by improper cone Exposure (°F) Supports _ Resistance to (Ịohansson 1980] Uníortunately, the abrasion and ílexing H cleanliness standards from Perry 1973 Spray Cyclone Dia 24 in 8.6.3.1 Principle of Baghouse Filters V= solids-conveying velocities for light materials range from 10 2.5 |am (8-9) counterbalancing variations of and viscosity 2with composed of particles andfibers aggregates (i.e.,low; char-ash design or7lD faulty design ofMineral the discharge receiver resistance of glass and ceramic can Organic be after Fiber a Long Short Combustion (cfm/ft )Composition Abrasion Acids Acids Alk mg/Nm totoless than 120mg/Nm density irregular Apwish =3 2-10 in H Vị = 357 fpsasto 10 We reduce solid particulates mg/Nm from raw Baghouse íilters (such shown in Fig to 15 m/s (30-50 ft/s), as shown in Table 6-1 One should n temperature ,13 ' dust) Condensatỉon aerosols are heated, ỉormed from installation, and especially once they have been the se Droplet 40-200 um Rankc d Many for ash, and 180 225 Yes 10-20 Cellulose G p G G Reducing the flow rate decreases the separator’s perforgasiíiers can produce very clean tar-free gas under gas that exits gasifier widely at 700°c The gas within few 4(63width m /h) (b) equal to the gasiíier 8-10) aretheused today to cools capture fine a dust select the cyclone inlet such pipe supersaturated vapors, as2astar and as water mist Highfrom Scrubber Tỵpe materials should beonly han-a dled little possible b mance, but it has slight effect on gas cleanliness If coarse particles are introduced into a fine-particle cyclone certain conditions However, it is best to design the gas feet of pipe to 300°c, which we will consider as the and separate Ayash from combustion gases 3.14 (2.5 cm/100 cm/m) (3600 s/h) velocity A Protein 2.5 Perry 1973 outlet pipe diameter the cyclone inlet to Wool o particles 200 250 No 20-60 Gor set Fwidely F equal p SprayTovver 2-4 fpsXDróplet chemical reactions, and íormed fromgas cracked 9(259 10“capability kg/m-s)(0.025 m) First, d _ , / temperature bag materials are soot not as in available as other because the dust loaddesign entrained thecloth inlet to the Cyclone and then two detrimental effects may occur the cleanup system with adequate for íibrous the very dirtybags gas cyclone inlet temperature Screening analysis of Polyamide c_ 3more baghouse filter consists of one or íilter Nylond o separator, 200 250 Yes 15-30 E p F G (J,m 53 ft- 0.489 high the pipe velocity and the cyclone according to the P500-1000 V 2(5)(14 m/s)(200 kg/m ) (3.14] hydrocarbon molecules Theyreduced tend toflow be rate very The fineresulting and of materials m/s (7000atfpm) (8-7) separator=is35also may produced block the the high Polyacrylonitrile that isparticles occasionally bysmall airbome_char 7-4) shows aevery mass mean particle diameter supported metal cages enclosed in a Second, chamber through loaded Orlon k large 240on (Fig 275 Yesinlet 20-45 G 8-5.the The G F proportions in lower Fig equations that Gappeared uniỉorm size dof velocities = I^m (8-10) effect is that this outlet dust load slowly increases with vvithin the separator may break the coarse which well above the minimum dp = 100 |im with a geometric Standard deviation ơg = Polyestẽr Dacron Bi which the 275 gases must 325 pass A deposit Yes of the up separated 10-60 parE G G — Part previously then can be loaded used to predict particle cutGsize anda 11 Perry 1973 Wave Plate 90° decreased flow rate inverse square rootto ofthe gas flow pipe rate bybuilds erosion, impact, and attrition latter effect 2.5 Particulate sampling indicates that total This dusta7-30 load peak Polypropylen 200 Yes Eby theinlet E equal E ticles soon up250 on the bag and establishes dust at cake of Oleíin Selectingdrop the cyclone widửi pressure — Venturi scrubber (40 in wgEgas o particles for char waves 7/16 in radius 0.15 in e 425 No 25-54 F E (Gengas 1950; Calvert 1972; Perry 1973) generate fine particles that may be harder to capture than m can flow is 5000pore mg/Nm through For a turndown ratio requirement of Polyamide appropriate size which additional particles 500 E G 8.5 Particle Movement and Capture diameter, the cyclone is designed by the proportions from — Packed bed (6 in deep, 30 Table 8-3.be Cylinder Wear for Gas Cleaned with WetCyclone CleaningDesign and Fabrics Filters spacing Nomex° 8.6.2.4 Example a anything The cyclone pressure drop is will previously present inaccumulated, theNo gas penetration (Perry 1973) For this Fiberglass 550 600 10-70 P-F E an 5inlet p 4:1, the maximum dust at Glass cannot pass As more dust the pressure It is 8-5 tempting tofps reduce inlet Fig For inlet width 2.5 cyclone cm (1 E in.) andwidth inlet with height cm ,1 the Mechanisms d ss Diesel Oil 2 Teflon D reason 500 No 15-65 Polytluoroethyle F E E E it450 is preíerable to provide a gas-disengagement space Dual Fuel — Diesel Oil/Producer Gas Wet For example, let us design a high efficiency cyclone for a 10 peak flow rate is P’ = 100 X [(10 mg/Nm )/(5000 'Cyclone cut diameter (•065)(p )(V is determined )A De drop increases When D the cake is an op= G i d vane; the upset cyclone proportions beenstream found (2 in.)however, thenfortheseparating cyclone inlet will be have /2 in.velocity spheres) Methods particulates from the gas Cleaning System Fabric Filter within theby thaneither two by stages Table Minimum Particle Size (13.4 hp) engine system o for mg/Nm )]cfm/ft =settling 0.2% Derating root the ne kw 8-2 timal thickness for removal, the bag israther agitated gas bygravity design, down to 1gasifier um **Fabric to reduce the effective number of gas rotations NThe t to as low as 3square 2of turndown, gasiíier — Wet impingement scrubber at 0.5 in water usually depend on the mass of the particles simplest _ (.065)(0.489 kg/m )(14 m/s) (O Ũ25 m) w of cyclones This will allow the of coarser particles to settle out for Various Types Scrubbers maximum for is=Pfair, = 0.2%/VÌ"= 0.1% pressure orpenetration by mechanical means, causing Dis the excess cake to 6increase — tilter collection efficiency above two and to reentrainment 1973) Thereíore, Cylinder wear 1000 hturndown gauge P= poor, Fm) method theKarbate particles settle under thea inAuence of n prior First we allows must determine the to gas flow(Perrỵ rate for typical 22% (0.05 (0.05 m) are related to to the cyclone separator Settling velocities — particles Disintegrator to 7-4 the bottom of the housing where it is eventually to remove finer using cyclones at a lower pressure dr drop On Fig we follow the particle size distribution line for an Minimum G = good, E = excellent gravity, with the gas stream flowing vertically upward or engine efficiency and an assumed heating value of 1300 aerodynamic diameter, 80% of particles dp = 20 |i.m, and the dp are captured with 80% eữiciency, and (8-11) those — Packed bed (6 in deep, C value size as shown in Figs 7-6 and 8-7 af particle =gasifier 31 01 mm (1.22 H removed 20 drop, it is to reduce theBtu/scf) individual cyclone diameter preíerable Particle Size, Imbert to the in.) data point where the cumulative fraction T ractor 0.015 mm 0.05 Cost rank, = lowest horizontally For horizontal separation, the process can be fps kcal/Nm (5.44 MJ/Nm , 157 Then speciíic gas 90% of particles dp = 30 um with diameters triple the d value are captured t equals 02 pc (im using multiple parallel cyclones (multi-clones) if necessary the maximum penetration allowing for turndown 0.028 0.05 8.6.2.3 Cyclone Strategy cost, 9of =the highest cost accelerated byism providing multiple Particles /hp-h spheres) G Spray tovvers 0.5-1.5 10 consumption 2.2 Nm Ví in scfm/hp) plates per horsepower We can see that cycloneshould achieve the desired *.l rm r\/ this f>r* •Design T wofds 1in the r Operation PofD 8.6.3.2 Action Filter Cake with 90% efficiency In other (63 /h](10 /m(1.43 ) horizontal Note that_3 gravity settlingcmchamber, cyclone, disintegrator, 03 0.031 0.06 0.007 a In (0.1%) The corresponding particle diameter dp = |im is the Air leaking into the char-ash hopper at the bottom of a also can be separated from the gas on the basis their mass or Nm(2.5 /kwh (25cm)(3600 cfm/kW)s/h) (Gengas 1950) of Du particulate Pont removal registered without excessive pressure drop cm)(5 — Impingement scrubber Fabric Filters our experience, the cyclones íitted to gasiíiers aie too large Cyclone spray 2-10 2-10 wire m'esh separator, and spray tower all have0.019 the same sitcut 2dpd50 p50> 06 0.005-0.010 (8the -1) point we wi.ll require = ^m, as shown by p80 cyclone separator deteriorates períormance substantially by using the centripetal íorce provided by a centriíugal scrubbers optimum particle removal Thereíore, present here an 10 — Cyclone Impingemenl 2-50beenwe 1-5 ie for However, there is íilters still a finite possibility ofíòund large parStandard of scfm) inertial and A 10 kw =engine require 30 Nm /h (20 of producer Fibrous bag have toticles be 08 0.020 0.011 14deviation—characteristic m/swill (2755 fpm) (8-8) dotted Similarly, removing the gas through bottom improves the scrubbers separator r example Packedand and line of detailed cyclone design 11 — Wire mesh (n =the 2)outpassing through a cyclone, so it is not advisable to use a gravitational separation mechanisms Sharper particle gas, which corresponds to a gas energy put of 163 MJ/h in the removal of particles down to E outstanding Oil contamination expressed 0.2% 0.3% 0.54% -1.97% 0.12%-0.25% fluidized-bed efficiency of the cyclone separator Cyclone cut size is the size particle that will be collected scrubbers 2-50 1-10 The recommended minimum gas velocity for conveying 12 indicated — (nStandard =at1)the cyclone cyclone as the method of- particulate separation as by mesh smaller devia- tion n The dp90 dp50■ (188 kBtu/h) TheWire volume gas inlet submicron sizes, as shown in thedust diameter ofsole pipe from thefor gasiíier to(8the -2 ) withaverage 50% efficiency Then weofcalculate, using the Oritice scrubbers 5-100 grade medium density dust leading is 15 m/s, and heavyoutlet (metal (2viscosity tests) as amount of insoluble 0.75% (9tests) gi cyclone 13 — Wave plate involves the beneíit of other or additional capture temperature of 300°c will be efficiency curve of Figs 8-2 and 8-11 Highinlet should be selected 5-100 to allow an ade- 0.8 Venturi scrubbers and density of producer gas from Fig 8-8 and assuming100 ash 50 is 25 m/s n turnings) Products in benzene after 100 mechanisms suchcyclone as condensation, cascading dif- íusion, or efficiency capture ofcurve small particles isum surprisingly 3proportions (Source: For example, agasitier cyclone rated at d p5Q =gas10 can be ex-ừom Skov 1974) e Fig Fig 8-5 High-efficiency Perry 1973, Fig 20-96 © 1973 Fibrous-bed 5-110 0.5 Fig 8-3 8-4 Typical Cyclone vehicle grade efficiency system showing (Source: cyclone Kaupp and 1984a, Fig cooler 138) (Source: Adapted density 2.0 (2000 kg/m ) and char hpected to capture size (dp) /im Source: Kjellstrom 1981, 2.4 mass Fig 8-10 transíer Cloth bag Similarlỵ, filter with intermittent reverse separation pulse cleaning (Source: Work 1955, p independent of the50% sizeofofparticles openings inTable the10íilter weave.Particle The Used with permission of McGraw Hillpoorer Book Co.; Kaupp 1984a, Fig 134) scrubbers having |i.m Source: Perry 1973, Table 20-41 483) reason for this is that the primary Fig 8-2 Scrubber pedormance and sharpness comparison (Source: See reíerence in Table 8-1) 72 Handbook of = = 95 a b c d 78 80 of Downdraft Gasiỉier 76 74 Handbook Handbook of Biomass Biomass Downdraft Gasifier Engine Engine Systems Systems Biomass Downdraft Gasitier Engine Gasitier Systems 79 Gas Gas Cleaning Cleaning and and Conditioning Conditioning 73 81 77 75 8.6.3.4 Safety Filter —-ị ụ If the íĩlter bag ruptures, contaminants harmíul to the engine will be released Thereíore, a saíety íilter or other effective warning means should always be used in conjunction with bag íìlters The saíety íilter acts by plugging quickly and shutting down the system in the event of an upstream equipment íailure A 200-mesh screen is suitable for a saíety íilter, as shown in Fig 8-12 8.6.4 Wire netting Supporti ng tilter Electrostatic (Cottrell) Precipitators í - To - the § mixer From the cloth cleaner Electrostatic precipitators have a long history of in- dustrial use to produce exceptionallỵ clean gas During operation, the gas passes through a chamber (as shown in Fig 8-13) containing a Central high-voltage (10- 30 kv) negative electrode A corona discharge forms around the Central electrode, which imparts a negative charge to all particles and droplets The negatively charged particles then migrate to the positive electrode, which may be vvashed by a continuous water stream to remove these particles The electrostatic precipitator ís effective for all drop and particle sizes Fig 8-12 Flame arrestor and saíety tilter (Source: Gengas 1950, Fig 166) dramatic, and the tar mist at the ílare could be seen to disappear instantaneously when the voltage was applied However, the electrodes and insulators soon became coated with soot and tar, and íormed a short-circuit path that supported an arc A means for cleaning the electrodes must be provided, along with a means to warm the insulators to prevent a water-condensation short-circuit These problems are being investigated A small precipitator (20 cm in diameter and m in length) was operated at SERI to clean gas produced by a 75-hp Hesselman gas generator powering a 15-kw electric generator The initial results were very For tar-mist removal, wire and tube electrostatic precipitators are preferred over the plate-type elecừo- static precipitator (Strauss 1975) Typical performance Discharge electrodes connected to negative Earth ed plate H.T inlet Outlet Suppo rting insulat ors Collect ing electro de Precipit ation electro Drain 'Weight Front elevationSide elevation Hexagonal tube type precipitator Two-stage discharge electrode vertical flow tube precipitator Fig 8-13 Electrostatic precipitator examples (Source: Strauss 1975, Figs 10-19, 10-20 © 1975 Used with permission of Pergamon Press) Gas Cleaning and Conditioning 83 Table 8-5 aTypical Períormance Data for Precipitators 70% of theElectrostatic total contained the initial fuel from hot suríacethereby and reducing toward suiface for tar acondensation, thecold amount of veryThis fine isto introduced at a energy concentration of vvithin 0.25 L/Nm , at 30 psig A typical sieve-plate scrubber can attain 90% efficien2cy for phenomenon called “thermophoresis.” and persistentisself-nucleated tar mist (Calvert 1972) spray pressure, and in a high intensity Sonic field of The heat losses from surfaces vary from to Btu/ft -h-°F, Dust Concentrations l-|im particles using 3/16-in holes, at a time speciíic velocity frequency 600 tothe800 Hz A sieve 12-s residence permits the depending on geometry of the gas cooler and Wetted particles tend to stick together better when they g/m at Operating Temp.Collecting Power The design of a good scrubber must maximize the gas- liquid of 15 m/sto (50 ft/s) Typical períormance characteristics of particles agglomerate to a size large enough to becooling captured temperatures involved Thus, a great deal of the at collide, assisting agglomeration Wetdrop scrubbers Consumption contact thereby area while minimizing the pressure throughhave the sieve-plate scrubbers are discussed in Kaupp (1984a) with 94% efficiency by a be 5-|im cyclone (Calvert 1972) higher temperatures can accomplished in the pipes and at been used widely, especially in stationarỵ applications for TypeotPlant Inlet Outlet Efficiency(%) w/1000m /h scrubber For instance, the gas-liquid con- tact area for a foam Coal Gas the of the gasiíier as wellbutas the in the cyclone Impingement Plateitselí, cleaning and Industry cooling the agas A scrubber operates by creating 8.7.2.4 If asuríaces condensation nucleus isScrubbers absent, degree of is much greater than for spray, gi ven equal energy 0.008 99.85 702 Peat gas producer 5.34inputs separators or other cleaning equipment However, as the gas conditions for maximum contact between the gas to be supersaturation (S) scrubber exceeds shown 200%in Fig to 8-16 400%, then The impingement-plate is similar 99.20 120.4 Cracking plant for anatural gas chamber at0.224 If a gas and stream enters liquid-filled high velocity 0.002 approaches ambient temperature, cooling suríace cleaned a scrubbing liquid medium homogeneous self-nucleation occurs Self-nucleation to a sieve-plate scrubber, exceptadditional impingement plates are 0.20 99.47 652 Producer gas from lignite briquettes 37.7 thiough a small hole at the bottom of the cham- ber, then all through some form of gas cooler is required produces extremely small droplet sizes The droplet growth arranged so that each hole has an impinge- ment target one Basic scrubber types and períormance characteristics are 0.10 99.7 602 Producer gas from sembituminous lignite of the entering gas must experience the subsequent impaction rate diameter is inversely to Gas the the droplet radius, sosurit Gas coolers exchange between and hole awayproportional fromheat the hole flowgas past the the edge of summarized in Tables 8-1, 8-2, and 8-7, and grade 28.7efficiency 0.006 99.9 903 and diffusion environments When water enters the gas proceeds first, accelerating withawhen droplet size rounding air, or atbetween the gas and liquid A typithe oriíiceslowly produces spray droplets that, íormed, arecal at Shale-gas cleaning plant 40.0 99.9 903 curves are shown in Fig 8-2 Scrubbers can be divided into 0.010 stxeamoven as a high spray, only a small 24.15 ữaction of the Coke townpressure gas cleaning radiator used ininvehicle applications is shown in Fig self8-3 rest, resulting 99.9 a large relative over velocity 1605 between dust impingement-plate, packed-bed, sieve- plate, spray tower, and 0.003 Nucleated condensation dominates homogeneous gas is close enough to the nozzle to receive the beneíit of 0.078 Coke town gas cleaning 17.0 99.8 752 Here, theand motion of the vehicle increases flowcondenses around particles these droplets The gas velocityair usually is abovea Venturioven scrubbers nucleation when nucleation sites are present Vapor impaction with high-velocity droplets 28.0 Spray droplet 0.039 Coke oven gas the cleaning 99.2 1404 gas cooler, so that coolingoperating air isfaces, available atdrop the 15 m/s (50 ft/s), andmore theconcave tỵpical pressure is void more readily within suríilling thehigher Small, difficult-to-capture be made grow in agglomeration proceedsdroplets rapidly,may causing the togas-liquid Oil 0.050 99.5 1805 speeds when the heat load is greatest In stationary 1.5 in water of gauge mbar) perSoluble plate An increased pressure drop fraction solid(4particles aerosol particles nucleate size with time until they are large enough to be captured by contact area to drop off sharply within a short4.73 distance from carburetted water gas Table cleaning applications, íorced ventilation required to solution move air raises the collection Theisrequired water flow rate even more readily byefficiency boiling point depression in A Source: Perry 1973, 20-45 simply providing adequate residence time in the scrubber the nozzle This effect seriously limits the collection ability of through the gas cooler is to gpm per 1000 cfm of gas Ổow small droplet grows slovvly by chance agglomeration until it volume Particles grow in size by agglomeration and spray scrubbers characteristics for electrostatic precipitators are shown in gravitational, or centriíugal means particles than reaches critical size; that, it grows rapidly by acting As the its gas cools, tars after begin to For condense at smaller temperatures condensation Agglomeration is efficiency par- ticle growth through 8.7.2.5 Venturi Scrubbers Table 8-5, indicating high capture 0.1 um, motion is dominated by molecular collisions They as a nucleation site Soluble particles behave as nucleation below 350°c As the temperature passes below the dew Almost all high-concentration clouds tend 8.7.2particle coìlision Scrubber Equipment The scrubber (Fig 8-17) critical captures large particles by follow Brownian motion behave more like a gas, The precipitator diameter should bewithin small 1enough to sites Venturi vvithout to principles, achieve size The charash point of the having gas (typically 40°-60°C), water also will to have the sametube particle concentration after impaction and impingement, and also rinses away any 8.7.2.1 SprayTovvers and may be collected by difíusion onto a liquid suríace In allow the corona discharge to be established at a reasonable dust particles in the gastar stream at condense Water present condensation helpsproducer to remove par- ticles ỉormation deposits thatwemight otherwise Some fine particles are this section will look theform basic mechanisms of particle voltage and large so thatisitsthe volume provide thein The simplest typeenough of scrubber spray will tower (shown temperatures below the taratwater dew point will act asthe nuclei but yields a contaminated condensate in process If A novel method to capture mist islength to provide water also captured here byfor diffusion High-velocity flow through movement and capture wet scrubber systems necessary residence with0.2-(Am a reasonable Low flow Fig 8-14), which time is composed of an empty cylinder with tars and particulates are removed from the gas beíore it enters fog nuclei and residence time VVater fog collection the low-pressure throat area atomizes the droplets The low rates in aample higher residence and size higher sprayresult nozzles The optimum spraytime droplet is 500 to 1000 Particles diameters 0.1 and fall within the the gas with cooler, then thebetween gas cooler will1 (im be able to operate pressure at the throat causes conden- sation, and the high efficiency ụ.m Typical upward superíicial gas velocity for a gravity so-called “open window.” They are the most difficult particles longer between cleanings All heat-exchange and gas-cooling Fig 8-16 Impingement plate scrubber (Source: Kaupp 1984a, Figs 142, 143) relative velocity of the droplets with respect to the gas spray tower is precipitator to ft/s,tubes, and as particle incollection tosuríaces capture,ineither bywith diffusion or in- ertial mechanisms They Multiple parallel shown Fig 8-13,is contact captures most larger particles by impaction accomplished when particles rising withand theuse gasa lower stream are too large to diffuse well but too small to settle However, permit a more compact precipitator design Table 8-7 Scrubber Types and Períormance mon problem for wetpresent scrubbers in small gasiíier systems Gas impact than with falling through the chamber at their scrubbers have no moving parts andThe are sparking especially well-suited they can be made to grow in size, since particles collide voltage a droplets single larger tube voltage for The atomized droplets a considerable suríace area for Method 8.7.2.3 Sieve-Plate Scrubbers Comments contaminant testing advisable for diffusion allparticles unproven designs terminal settling velocitỵ The spray tower is especially wellfor very dirty, corrosive, or abrasive might Pressure Drop VVater naturally and agglomerate into larger that are easier tube precipitators is shown in Limit Table materials 8-6 In that practice, Size fine particles to beis captured by Furthermore, Column (in.) inscrubber suited as adamage preíilter for extremely heavy dust loads (over 50 otherwise a blower Particle impeller (Calvert Cut Dia 1972] tocondensation capture precipitators are operated at the highest operating voltage the throat improves captureofthrough diffusion Acm sieve-plate (Fig 8-15) consists a vertical tower (dpso) g/Nm ),excessive which would plug other types of scrubbers Auxiliary Equipment without sparking (Perryless-open 1973) One-second delays 8.7.3 because theofphenomenon Steían motion The atomized with a of series ofhigh-efficiency horizontalof perforated sieve plates The One method collection uses primary 8.7.2.7 Packed-Bed Scrubbers Ịim Fịg 8-17.cone Venturí scrubber with centrìtugal entrainment (Source: Calvert 1972, Fullspray nozzles produce 500 toresult 1000 |im eữective droplets, between sparks have been found toseparator in Gravity Settling >30 Low droplets rapidly agglomerate in the diffuser section, where scrubbing liquid is fed into the top of the column and flows separator; veryfollowed large collection of large particlesCoarse by inertia and diffusion, Fig 5.3.6-1) The packed-bed (Fig 8-19) simple open in 8.7.3.1 Gas which fall with a scrubber settling velocity of 13isft/s For aand spray tower precipitator operation collection through diffusion continues Entrained droplets downward viaCooling downcomers to plate; the gas to andfrom bulky by an increase in fine particle sizeplate by agglomeration, andbe design, andtheuses spheres, rings, or saddles as ran- dom Water vapor acts as an inert dilutent of producer gas, initially 53 ft high, value of dp 50 is um containing captured contaminants are separated inertially from scrubbed is introduced at the bottom of the column and passes íinally by collection and entrainment separation The rate of Application of a negative (rather than positive) voltage on the1 cm/1 Ocm of Massive >5contact Freeand draining coarse demister packings toPacking enhance the gas-liquid area Packed beds lowering thegas gas heating value ultimately lowering engine the cleaned Liquid recycle requires cooling and removal upward through the sieve holes counter to the liquid Contact agglomeration is proportional to the total number of particles center electrode is íavored because this arrangement results 8.7.2.2 Cyclone Spray Scrubbers column height are more for both and zone liquid-gas heat when theeffective gas leaves the gas charabsorption gasiíication at about power orAgglomeration burner ratìng, shown ìn replenishment Fig.by 8-21 Much of with this of captured materials, orisas disposal and betvveen the liquid and gas is enhanced by using plates present also assisted the presence of in a more stable corona and less sparking The cyclone spray scrubber combines the virtues of the spray exchange than they are for particle collection However, 800°c, the sensible heat of the1gas accounts for about 15% 10droplets Fiber Packing water cm vapor can be removed by cooling the producer gas and Viscous materials can cause bubble caps, impingement plates, or sieve plates that act as nuclei The typical through the capelectrode 0.1particleto 0.5it The collectioncondensing efficiency out and droplet size are deter- mined by tower and dry improves the packed bedscurrent arecyclone excellent for turing liquids of the initial energy in theseparator wood If It the gasis entrained islow: burned while subsequently the water plugging Particles tenddrop: to scrubber move toward suríace on which mA/m ofefficiency collecting suríace (Perry Halfwave the efficiencies maya be in- creased by reducing Thepressure sieve-plate captures large particles byconimcapture of the spray droplets in superíìcial ordinary spray For entrainment the optimum gas is still hot, then theseparation, sensible heat can be1973) utilized However, if The amount of water vapor remaining afteristhe cooling Pretormed Spray Low densation water consumption taking place This phenomenon to and asof rectiíication a 50in to 60 Hz>5 electric supply the throatisarea to raise theHigh pressure drop The referred efficiencies pingement and impaction, and small particles by dif- íusion scrubbers byof spray-droplet impact Theprovides cyclone velocity packed-bed scrubbers using 1/2-in spheres 10 the gas isfor to beincreasing used an internal-combustion engine, it is must condensation steps can betend determined readily from the lowest “Steían motion.” Particles to migrate away adequate time for extinguishing sparks Venturi scrubbers are discussed in Calvert (1972) Gas passes upward into the water layer through holes in the spray scrubber also thereentrainment advantage, compared the to ft/s Floodinghas and occur above a gas for sticky materials be 12 cooled to prevent preignition, thewith engine Gas Atomized Spray >5 to improve 0.002 (0.001) 5.7 to vvhich Good temperature the gas has been cooled If sieve plate The high gas velocity through the sieve holes spray scrubber, of being self cleaning, of collecting more velocity of consumed The power by Venturi and Sieve >2 gasprecipitator volumetric efficiency, andantoelectrostatic íacilitate cleanup is very(2.2) 8.7.2.6 Eịector condensation has Venturi occurred,Scrubbers then the lowest gas temperature is atomizes the scrubber liquid into fine droplets, and most particles regardless of issize, and operating smaller ft/s The pressure drop 7.5 to 8.5 in wateratand gauge forpressure a 6-in.Plate Scrubbers >1 (8.9) low, typically 1.5 w/hp (Strauss 1975), The thermal energy in the raw gas may be eitherthe dis-pressure sipated, 22.6The of course the of dew point of the liquid gas mixture.pumps The water scrubs vapor velocity the contacting inertial particle collection takes placeboth just as theand bubble is drops A basic design is shown in 8-9;in others are 91 (35.9) deep bed Performance characteristics Submicron of packed drop verỵ low, at considerably lessFig than ofbeds water usedalso foris low-temperature applications such 1as drying, or content of thegas gasinmay be determined from Fig as 8-22, or the the entrained an ejector Venturi scrubber, shovvn in íormed, by impaction on the inner suríace of the described in Strauss (1975) Commercial cyclone scrubbers shown in Fig 8-20 Packed beds are free-draining; they may7.5-20being High-voltage requires rigorous saíety measures Centrifugal 1-2 (3-8) recycled intoequipment the gasiíier by using the energy to preheat In the psychrometric chart of nozzles Fig 7-19 Note that the tangential moisture Compact; good for Fig 8-18 Spiral spray impart axial and bubble Diffusive particle collection dominates as the bubble are irrigated better than 97% efficient at removing with be to remove accumulations with particles water addition, íailures loss of flow the incominguníoreseen air Eachpower method has may been cause used a on gasiíiers fractỉon roughly with each 10°c increase in must the dew preliminary cleanup velocities to suríacethe doubles liquid jet The contacting liquid be rises 8-6 Here, active agents canSparking reduce the collection diameters1972) greater than |im The ability, cut diameter for a cyclone (Calvert electrostatic precipitator’s cleaning with a subsequent Table Electrostatic Precipitator Potentials Airblast preheating was used exten- sively in European point teraperature We can calculate that at the 0°c dew removed after the scrubber by a suitable entrainment Baffle Plate 2.5-7.5 (1-3) Large coarse collector efficiency because of Steían motion, but a cold water 20 (solids) spray scrubber is about an order of magnitude less than that release tars to the vehicleofgasifiers to engine improve the gas and to permit wetter fuels point, water vapor represents 25%scrubber, of the gas Cooling 8.7.2.8 Entrainment Separators separator to a Venturi thevolume ejector Venturi scrubbing Compared liquid receiving a hot aerosol increases the (mist) for either a dry cyclone or spray scrubber to be gasiíied (Schlãpíer 1937; Egloff 1941; Lutzbe1940) the gas Diameter, torequires 40°c reduces the water content to lesstothan 8%, Pipe Sparking Potential, scrubber both more liquid and more power achieve Entrained liquids from the wet scrubber must thoroughlỵ collection efficiency A deeper foam reduces inertial effects 8.7Wet Scrubbers volts Impingement 2-3 10-50the (4-20) in Recoiland bounce; can reentrain resulting inpara substantial improvement in gas quality ticle collection gas movement Eịector Using sensible heatgasto stream more than preheat the aairblast removed from the because they carry slurry or of Root Mean and same increases collection byPeak diffusion Inertial collection is 8.7.1Entrainment Principles of Wet Scrubbers Square because (5) slightly Can be clogged heat the fuel hopperEntrainment is hardly justified the gas is dirty 32Venturi Water vapor dilution will be minimized by using fuels that are captured materials droplets are typically greater only increased by adding plates or increasing tho 59,000 45,000 As weonlỵ havea|nm previously stated, particles diameters Separator and small quantity of (15%)with is involved If larger usable as drop possible and then condensing water vapor to remove than 10 and may beheat captured using a variety of pressure Mechanically Aided 1-2 Acts asas adry blovver High povver and 58,000 76,000 than um settle by gravity and inertia They follow heat is desired, then athepacked enginebed, ex- ahaust gas fiber andStokes’ engine it from the gas techniques, including packed bed, a maintenance 90,000 69,000 law and can be are captured by impaction, Moving Bed separator, Good mass transter coolant fluid much cleaner and more abundant of7.5-15(3-6) cyclone separator, an impingement a spraysources tower, or 12 100,000 77,000 representing aheat, settling chamber.60% Poor entrainment Fabric Filter 0.3 separation has been a 13(5) Excellent; can be clogged Forgases at atmospheric pressure, coma Source: Compiled from data in Calvert 1972 100°F, containing water vapor, air, CŨ2 and mist, and negative-dischargeelectrode polarity 146) 84 86Handbook HandbookofofBiomass BiomassDowndraft DowndraftGasitier GasiíierEngine EngineSystems Systems 88 Handbook of Biomass Downdraft Gasifier Engine Systems Gas Cleaning Cleaning and and Conditioning Conditioning 85 89 Gas Gas Cleaning and Conditioning 87 the raw gas are subject to ash and tar buildup, so ample cleanout ports should be provided to clean these suríaces without requiring extensive disassembly 8.7.3.2 Gas Drying The diluting effect of water vapor on the wet gas heat- ing value (HV W ) may be determined from the heating value of the dry gas (HV fj) and the moisture ữaction (F m ) from Packed bed F mseparators good for finer Fig 8-22, where = water vapor are partial pressure/total droplet removal For example, Fig 8-24 illustxates that a (absolute) gas pressure 6-in,- deep bed packed with l/2-in.-diameter spheres will Then, HV W is found from capture 50% of 2.5-ỊJ.m diameter droplets from a super- ficial gas velocity at 1.5 m/s (5 ft/s) Deeper beds and íiner packings will increase collection HV W = HV (8-12) d (l - F J períormance; however, excessive gas velocity may cause reentrain- ment, deteriorating overall performance The mini- mum packing size is limited by the fact that smaller packings more rapidly become plugged by viscous tar deposits In these cases flow can be restored by stirring or replacing the packing o It was common practice during VVorld War II to pass the gas through wood chips, cork, or other íibrous materials to remove tars Some of these materials subsequently can be used as fuel in the gasííier and thus Raschig ring Berl saddle Liqui d in dispose of the pollutants Fiberglass íilters have been used to clean gas Qohansson 1985) as has char (Humphries 1985) Fiber-type demisters have limited applications be- cause viscous tar deposits on fine wire mesh not drain freely and are prone to plugging Packin g An electrostatic precipitator may be useful for entrainment separation However, these units have not yet been proven reliable for continuous operation with producer gas Les Tellerette Gas distributor and Fig.8-22 Water content of saturated producer gas (Source: Gengas 1950, Fig 82) packing (The moisture íraction approximately the same value Fm 8.7.3.4 is for either mass íraction or volume íraction of water, since Nm of water and Nm of producer gas each weighs approximately kg.) The Liq uid has on the heating value of a effect that vvater- vapor dilution out 150-Btu gas is shown in Fig 8-21 sig ringPreventing Further Condensation The scrubbed gas may have a very high humidity (from 80% humidity to the saturation point) Further condensation can be expected to occur either as the pressure drops or when the producer gas is mixed with combustion air To prevent íurther umvanted condensation, one may heat the gas or secondary air (the engine ìntake air) vvith engine exhaust heat as shown in Fig 8-25 Pall ring Methods of measuring gas moisture are Fig.8-19 Packed tower and packings (Source: Kaupp 1984a, Fig 151) presented in Chapter To minimize the power loss Intal ox sadd le from water- vapor dilution, the necessary cooling suríace can be roughly determined from Fig 8-23 Ample ventilation must be provided to cool and condense the gas with a 60°c dew point from 700°c100 down to 40°c 8.7.3.3 Collectio Demisting/Entrainment Separation Reentrainment A n common problem with otherwise degrades droplet adequate inadequate removal efficienc gas cleanup systems iscollection above of entrained 50 in H20 y forscrubber liquids oil 50 Theụm gas emerging from the gas cooler and from wet scrubbers droplets contains droplets of dirty water entrained in the gas stream in engine6” Most trouble is caused when these entrainment-borne contaminants deep bedform deposits on the engine parts Therefore, they must be removed to íinish the job of gas puriíication Wet cyclone separators Fig 8-9), with 10 20(shown 50 in 100 a max- imum spray velocity of 45 ft/s (15 (AP) m/s), are good for Pressure drop in.H 20 removing large mechanical entrainment drops more than 100 | im diameter have low efficiency for fine mist particles Fig in 8-20 Pertormancebut otpackeơbed less than 10 |xm in diameter c Fig 8-21 Power loss due to moisture saturated producer gas for 150 Btu/scídry basis gas Fig 8-23 Gas cooler surtace requirements for various outputs at 700° (Source: Gengas 1950, Fig 99) 90 Handbook of Biomass Downdraft Gasitier Engine Systems Gas Cleaning and Conditioning 91 9.2.3 Feeding Solids rni^ippo During testing, fuel can be fed manually Chapter ✓ to small gasiíiers However, there is the danger of running out of fuel, which in ỉ ° / Bcharcoal e đ d e p t h burns turn overheats the gasifier as the remaining I Pa r t i cl e Gasitier d e n si t y Systems q/cc Level alarms or other Con trols t are strongly o f p s recommended A f ps o f p s operation o fps for gasiíier systems intended /for continuous (see / □ 10 fps Chapter 10] ^ E x p e r i m e n t a l ỵ s 9.1The Complete Gasitier System T h e o r e t i c a l stances and should be treated with due caution Col- lected that cannot be recycled to the gasiíier or burned on site 9tars may need to be treated as hazardous wastes They should not be dumped on the ground or released into waterways Prevention through low-tar gasiíier designs is the best cure for tar (see Chapters and 5) 8.8.3 Condensate can support a shear stress, solids can bridge and arch in The liquid channels condensate producer gasof may contain Biomass fuels are only partially free flowing íram a hopper by cylindrical An from important measure the difficulty The previous chapters have discussed the major opera- tional substantial of tars andthe phenols are iswellgravity alone so bin stirrers, vibrators, or shakers may be of íeeding amounts a particular solid, angle Phenols of repose, tMe components of a gasiíier-engine system However, no system known and will kill soil bacteria spread on the required for even fuel delivery Biomass can be moved averagegermicides angle from a horizontal plane ifassumed by is stronger than its weakest link A complete system requires J L ground If biomass releasedpieces into waterways, therancondensate could laterally and vertically by conveyor belts, chain drags, bucket individual when they are domly piled up 10 t dry the biomass, means to store and possibly to feed 20 the damage lifeforms by those elevators, augers, pneumatic For liquids, this supported angle is zero; for waterways some solids, it can be Di a m eblowers, t e r ( m i cr o n s)and vibratory íeeders biomass, to remove char-ash, to push or pull the gas through (e.g., Syntron type), widely available in agricultural handling greater than 90°!water, For this reason, vibrators, shakers, and For condensate as with tars, prevention is rakes the best the System, to clean the gas, and to burn the gas during Fig 8-24 Entrainment separaỉor otpackeớ bedfor removal equipment Again, thosecollection with efficiency experience with thedroplet particular chains, live bottoms (on trucks), and a formahost oftion ingenious cure Methods of minimizing condensate should startup, as 1973, shown in the Ễront of this book and in Fig 9-1 (Source: Perry Fig 18-142) biomass form should be contacted for íeeding and equipment devices are used widely in the industrial be considered fullỵ early designand andagricultural selection ofsolidthe A complete system also requires instruments to measure suggestions feeding applications Much time and money can bemay wasted system (see Chapter 5) Gas moisture content be pressure, flow and temperatures at 79 crucialUsed points, and of McGraw reinventing these devices, so(the thedrier, designer is advised to Fig 9-3 Solids íeedingrates, devices (Source: Perry 1973, Fig 20© 1973 with permission Hill Book Co.) minimized bỵ using dry fuel the better) and by 8.8 Disposal of Captured The flow of solids in the gasiíier is also consubjectditions to irControls to establish the required contact others with experience in íeeding the particular form recycling heat back into the gasiíier through an air-blast regularity and andwill can be cause great difficulty Contaminants Instruments andinterruption Controls discussed in Chapter of biomassCondensation being used from the gas may be minimized by preheater during gasiíication, resulting in such problems as bridging, pipeline disữibution or synsas for chemical synthesis (Reed 9.3.2limiting Fans 10 the amount of gas cooling so as to use the gas above 8.8.1caking, Char-Ash 1982) channelling, and rat-holing The importance of Propeller-type fan blades usuallyThe generate 1.25 cm (0.5 its water dew point (40°-60°C) loss inunder engine power or uniíorm feeding cannotfrom be overemphasized experts in The char-ash removed producer gas is Solids freeand of dangerous 9.2Storing, Feeding, and Sealing in.) of water gauge pressure and are used in gasiíiers onlythe to the costs of larger engines may be more than offset by the field should be consulted (Guzdar 1982, disposed Miles 1982) materials and can be burned or saíely of in a move airinthrough heat exchangersdisposal and radiators They are not savings the cost of condensate landíill.Characteristics When burned oftoSolids white ash, char-ash contains 9.2.2 storage 9.2.1Char-ash must be removed from the gasiíier and stored as it is suitable for moving gas against any resistance valuable minerals that may be beneficially retumed to the A closed bin, silo, or hopper must be supplied to hold the Solids are many times Eịectors, more difficult to feed and be seal agaỉnst produced An air-tight char-ash receiver should provided, 9.3Fans, Blovvers, and soil.flow Charcoal is a valuable, clean-burning fuel, worth several biomass íeedstock (chips, cobs, pellets, etc.), to prevent it gas liquids and gases Because they since thisthan char material is combustible and may reignite Fig 9-2 Batch fed gasilier with lid (Source: NAS 1983, p 68) Compressors times the value of wood Alternate uses and possible markets from getting wet In many cases, industrial or agricultural spontaneously In addition, it may be necessary to cool the deíinitely should be examined containers are available in appropriate sizes at low cost 9.3.1receiver Importance ofweight Gas-Moving Systemmay be only 2% Although the of the char-ash Design to 5% of the material weight of thebebiomass the gasiíier, its Larger char may saleablefedforto íurther charcoal volume may combustion, represent a larger fractionmethod of the for volume of the gasiíication, orabriquetting It is important to provide suitable pulling or original the biomass be- cause of its lower density The required pushing gas through the gasiũer, and since the mass of gas In addition to valuable soil minerals, charcoal has been receiver volume must is thereíore larger be calculated measured and air being moved thefrom mass successfully used as a soilmuch conditioner than in Japan, result-ofingfuel in char-ash bulk densities, power which may may be range from 0.064 to 0.4 being fed, considerable required The improved crop yields (Kishimoto 1985) It also has beenengine used 3 g/cm íueled (4-26 lb/ft ) being canfeed serve this purpose as a livestock supplement to reduce digestive problems Every internal-combustion engine is receivers a compressor, since it Itand should be mentioned here that ash can has contain meat hormone ỉevels (Taylor 1986] Charcoal long compresses and They fuel toin 10 to developing 30 times explosive gastheeven whenaircold been known to been considered aintake premium cooking fuelhave many atmospheric pressure igniting the fuel When an engine ignite on startup, and beíore precautions should be taken against this countries operates on producer gas, it can also provide suction and 8.8.2 Tar for the gasiíier However, an engine is a very 9.2.4compression Sealing Solid Flows A gasifier that producesformore than new 0.5 g/Nm of tar can- not expensive compressor testing (Arthayukti Gasiíiers may operate at pressures up togasiíiers 20 in water gauge be suitably cleaned foris engine applications dueother to the large 1984; Breag 1982) It desirable to use some method above or below atmospheric pressure, which makes it amounts of the tar that mustisbeless captured andtodisposed of For a for moving gas that sensitive tar, char, and soot necessary to provide a seal through which the biomass can worst-case tar production scenarioalso of 2may g/Nm (0.2%), up type to during testing Full engine require pass without leaking air power or gas Proper seals some are very g compressor of tar per hp-hmay arise10) with each horsepower Thus, a of (see Chapter important, to ensure both gas quality and safe operation (see 100-hp engineofwould produce up to 4.8 kgbeofpulled tar in (suc24 hours, The question whether the gas should tion Chapter 12) or about L At room temperature, tar is a viscous, operation) or pushed (pressurized operation) throughslowthe Gasifiers the World War IIItera were batch-fed through a flowing,isfrom molasses-like contain carcinogenic gasifier important, andfluid one íỉndsmay strong advocates of each lid could be sealed tightly, as shown in Fig 9-2 The sub-that Gas method leaks from gasiíiers operating above atmospheric spring-loaded lid would pop open in the event of an internal pressure can be dangerous because of the possibility of gas explosion As long as the gasifier was íilled quickly, the leaking carbon monoxide out of the gasiíier; air leaking into expelled smoke could be tolerated as a nuisance gasifiers operating below atmospheric pressure can cause Gas ftows ZH^Z explosions Solid/liquid flows Measuring devices There are two basic types of solids íeeding and sealing dnvices—mechanical seal type where the seal mechanically prevents gas passage, and plug seal where the íủel acts as its own plug and seal such that fuel velocity into the gasiíìer is greater than gas velocity out through the fuel plug It should be noted that rotary valves and gate valves are also good Exha firestops for ílash- back or explosion prevention Inert or air ust purgepipe gas should be used in pressurized gasiíiers to offset leakage through rotary valves Additionally, there is the Note: stratiíied charge gasiíier where air enters through the top at The pressure such that for operation above a atmospheric secondar minimum gasiíỉcation rate, all smoke is drawn down into the y air' fuelpipe bed, and a lid is unnecessarỵ In many cases, the biomass runs feed can help to act as a seal in a long auger or vertical pipe Secondary air valve However, the pressure drop through the fuel is small, and the technique will not work if the gasiíier fuel inlet is under a Gas valve positive pressure of more than 2.5 cm (1 in.) water gauge Various solids íeeding devices are shown in Fig.From 9-3 Star valves, which rotate to feed the fuel, are gasiti eravailable commercially Heatingisofsecondaryairbyexhaustgasheatfrom theengine (Source: Gengas IfFig.a 8-25 gasifier to be operated at high pressure, it becomes 1950, Fig 85) exceedingly diữicult to feed biomass through a single seal Lock hoppers that use two slide or bell valves supplying a E = ejector L = metering íeeder as shown in Fig 9-4 have boen used with level control T = biomass at pressures up to 30 atmospheres for making thermocouple medium-energy gas for AP = differential pressure gauge or control m = feed mass flow 1982) measurement device Fig 9-1 Gasitier system showing means of moving solids and gases and positions for various 'Instruments and Controls 94 Handbook of Biomass Downdraft Gasitier Engine Systems Handbook of Biomass Downdraft Gasitier Engine Systems 92 Gasiíier Systems 95 Gasiíier Systems 93 and mixes with the driven gas Optimum ejector dimensions 9.3.3 Blovvers are discussed in Perry (1973) Centriíugal blowers (Fig 9-5) can generate pressures on the 9.3.5 Turbochargers and Superchargers order of 100 cm (40 in.) of water gauge pressure and are quite The power output of internal-combustion spark and diesel suitable for gasiíier testing To generate these pressures, the engines is directly proportional to the energy content of the blowers must either rotate very fast or have a large diameter, intake fuel-air mixture A mixture of producer gas and air has since it is the centriíugal force that creates the pressure The 30% less energy than a gasoline and air mixture, resulting in a blower can tolerate, and in fact will remove, a certain amount minimum 30% povver loss at any given rpm Intake pressure of tar and particu- lates, but a means for draining and cleaning can be in- creased to overcome this power loss by a the blower shouldbe provided Blowers canbeused turbocharger using engine exhaust pressure to run a turbine, eithertopush the air into the gasifier or to pull the hot gas or a su-Straight-blade, percharger operating from the engine shaft power through the system at negative pressure Considerably more or steel-plate, fan This pressure boost is widely used in diesel engines and power is required to pull the gas through the system than to racing cars, and is coming into wider use even for sparkpush air because there is necessarily more mass to manipulate ignition engines and the gas is less dense In addition, suction fans must be capable of handling a higher temperature than fans pushing Positive displacement rotary blowers (Fig 9-7) and suair into the gasifier Most blower breakdowns occur due to perchargers can achieve any pressure required, but they so deposits on shaft seal and impeller or erosion of the case at higher Capital, operating, maintenance, and energy Reliability is limited by deposits costs This increased cost must be weighed against the lower cost of using a larger engine 9.3.4 9.4 Flares and Product-Gas Burners Forward-ciưved-b!ade, or “Sirocco”-type fan 9.4.1 Flares Plares sometimes may be seen at oil wells or refineries in which excess gas burns with a luminous flame In order to produce a nonluminous flame, it is necessary to provide enough air and residence time to burn the soot in a hotter, nonluminous flame This is called a gas incinerator Raw producer gas contains up to 40% carbon monoxide and up to 20% volatile tars, making it absolutely essential that a reliable incinerator be available during testing to burn the gas The incinerator must be sized to fit the gasiíier Most of the principles discussed below for incinerators also apply to developing burners for producer gas The three essential elements necessary to combust any gas are residence time, temperature, and turbulence (the three “T’s” of gas 130 combustion) Residence time re- quires a suữicently y large chamber for combustion to proceed to completion High £120 \ LU temperature is by—I using a reữactory lining on the HO " achieved V , can be — burner Turbulence generated by high-velocity K I _ V, ‘V mixing of the |com- bustion air orI fuel (for instance, by passing it ^ - 'N \LV >> air with the gas through a nozzle)stroighỉ or by tangentially mixing ' 70 bậQđe"'' le' The reader to books on combustion and \burners for ềio60 is reíerred Forwarơ’ 2-stoge a more complete Curved discussion (e.g., Perry 1973).> prvpeller 50 V \ \ a pilot 40 Incinerators for toxic chemicals and gases \require ỉ flame to assure combustion operated on methane or \ propane, \ down \ an ignitor the s 0to start the flame, a flame sensor to shut burner8 if■the flame is extinguished, and a control system to I the0air mixture 20 40 and 60 stack temperature 60 regulate 20 100 Ị20 Í4Ọ 160 Volume in Per Cerrt of Volume ot Highesl Etticie Approximate characteristics of varioưs types of fans ncy Fig 9-5 Centritugal blovvers (Source: Perrỵ 1973, Figs 6-37, 6-38, 6-39, 6-41 © 1973 Used with permission of McGravv Hill Book Co.) Ejectors Ejectors are a very convenient and simple means for moving dirty gas No moving parts are exposed to gas contaminants Eịectors (Fig 9-6] use the motion of a small amount of one gas to move larger quantities of a second gas, oíten at negative pressures During startup, the gas produced initially is very tarry and may quick- ly clog cleanup and engine Thereíore, one should use a fan or eịector during startup to send this gas to a product-gas burner until low-tar operation is reached Compressed air, nitrogen, or steam can be used to drive the ejector VVater jets can also be used to move, cool, and clean the gas Ejector design is based on the principle of the conser- vation of momentum of the driver gas as it aspirates sliding-vane type o( rotary blower Fíg 9-7 Positive displacement rotary blovvers and compressors (Source: Perry 1973, Figs Fig 9-6 Eịectorpumpíormovinggas (Source: Perry 1973, Fig 6-73 © 1973 Used with 6-49, 6-50, 6-51 © 1973 Used with permis- sion fMcGraw Hill Book Co.) permission of McGraw Hill Book Co.) 96 Handbook of Biomass Downdraft Gasiíier Engine Systems Gasitier Systems 97 method Hovvever, the small openings are easily clogged by Standard Pitot tube shovvn in Fig 10-1 is recognized as aliner primary Standard for velocity ►ị Retractory “risa" sleeve suitable for dirty gas Its calibration factor is approximately K 10.2.2.1 Floating Ballp -12 Rotometers measurements When properly designed, it has a unit = 0.83 for velocities upInstrumentation to 50 For more accurate work, and Control in.-ft/s.using Clean gas flow can be measured a rotometer (ball and calibration íactor, K = For pipes under the individual probe should be calibrated tube) flowmeter, which comes in a wide range of sizes up to cm (4 in.) in diameter, the average velocity is 90% of the against a primary Standard 100 scfm The gas must be clean at the rotometer, and center-stream velocity, ±5% For air, the gas velocity (ft/min) low pressure signal characteristic of Pitot measurements meters the gas cleanup system and com- ponents, 10.1The Needusually for Instrumentation thereíoreThe rotometers can be used only on and air or is given(see by below), the equation: requires a sensitive and delicate readout A typical gasiíier and any components that are prone to plug- ging, as shown in oxygen streams at the gasifier inlet In addition, rotometers Control pipe velocity of 20 ft/s will show a pressure drop of 0.09 in Fig 9-1 The total to where: atmospheric V = 1096.7 K [Àp T P std /(p G Twith )] 1/2 (10-1) testpressure std P testrespect must be calibrated for the speciíic gas to be used, and the water gauge This pressure drop can be measured by a Dwyer The gasifiers of World War II were batch-fed, and gas flowed pressure (known as “gauge” pressure) may also be measured reading also depends on the absolute gas pressure PGthe = gas density at Standard conditions Magnehelic® 0-0.25 in water gauge pressure gauge, which to the engine in response to the vacuum created in the engine at gasiíier outlet, the cleanup outlet, and (if the gasiỉier is Nevertheless, they are very convenient flow measurement has aGas resolution of there 0.005were in no water gauge, a pressuie As a result, usually Controls or instruments operated at a pressure above atmospheric pressure) the air ) Ap = the differential pressure in inches of water devices readability of 5%,ofand velocity readability of 2.7% other from than those theaengine and vehicle The corresponding inlet In locations where occasional measurements are suffip =connections gas pressure absolute (atmospheres] blower tradeoff was that a great deal of operator expertise was cient, should be capable of being closed off when The velocity of a gas in a pipe is highest at the center and 10.2.2.2 Gas Flow by Differential required order to gas know when can to shake stirflow the theyTare not in use Pressure Measurement zero at theinwall The velocity be usedtheto grate, measure = gas temperature [Kelvin) fuel bed, the fuel hopper, and clean system, wellthat as by thebe velocity proíile in- the tegrating theasresult The pressures within the gasiíier will be close to atmoGastraversing flowfill may measured byand Variable a number of methods K = calibration constant Air how to operate the vehicle onoriíĩce hillsair and in tratĩìc spheric pressure (except for high-pressure gas producers) and port produce a Meters differential pressure signal Pitot tubes, Oriíìce The meter shown in Fig.oriíice 10The subscripts std and test refer to Standard conditions Propane torch as the modem automobile has a number Instruments, generally will be measured in cen- timeters (inches) of water meters, meters, and flow-restriction meters all but are 3Just gives aVenturi much higher pressure reading than aof Pitot tube, and actual test conditions, pressure in the drops system.respectively If the added pressure drop can can be sensors, lights, and Controls, gasifiers built column.*drop Pressure and differential pressures based measuring the of pressure drop produced by gas flow it does on sowarning at the expense creating a slightly higher The Standard Pitot tubeis filled shown in Fig 10-1 tolerated, oriíice meter usuallỵ preíerred over the today should incorporate instruments and measured then by a the U-tube manometer with colored liquid across or through the device each technique, the velocity Fig 9-8 Product-gas burner for testing smallFor gasitiers introduces the smallest pressure drop of any pressure-sensing other altematives because it is low in cost, can use more Controls improve performance, Liquid-íilled manometers are simple devices that use a ũuidis proportional to to the square-root of the pressure drop (Ap) flow (usually rugged, less sensitive is not small convenience, and safety íilled coloredreadout, water orandlight oil)sensitive tube to to measure A small flare, suitable for burning up to 200,000 Btu/h of than the costs replacing unit with a solid fuel burner amounts ofFor tarsof and particu-the lates An oriíice meter consists of pressure convenience and portability, they can be made During and development, measureare producerresearch gas, is shown in Fig 9-8 Itmany is made from aments 5-gal can afrom washer-shaped plate with plastic a hole diameter d that is placed in ílexible, transparent tubing and a meter stick required determine operating parameters and to Close coupled gasiíier burner systems are able to meet lined with to an 8-in.-ID ceramic fiber risa sleeve (Risa sleeves the gas line, units with are a plate thickness at therange orifice edge of no Commercial available in a wide of accuracies, determine Controls be emission requirements with no expensive pollution abatement are used in metal where íoundries, hightemperatureshould flue lines, and more than 3% of the pipe diameter, D If the oriíice is an from 0.25% to 3% of the full-scale reading applied However,A apropane production system equipment oil-buming íurnaces.) torchgasifier or suitable pilot(like ílamea accurately centered, round opening of diameter d, the producrequire relatively For more sensitive measurements, an inclined-tube injected tion tangen-car) tiallyshould at the bottom maintains a high diameter ratio, d/D,gas should between fuel 0.3 and 0.6 A quality means UpdraỀ producer anbeexcellent for highfew key Instruments and Controls manometer may be usedis (Dvvyer 1960) Typical inclined-tube temperature on the wall Producer gas is injected tangentially for measuring the differential pressure drop across the plate, heat applications The high tar content does not need to be scales can be read to 0.1 in water gauge, and curved-tube upstreamgasifiers from the flame mixes with the propane Ideally, of propane the íuture will and operate automatically and as shown inand Fig.adds 10-3, must be provided removed, to the heating value Furthermore, the manometers (e.g., the Dwỵer Mark II) provide high resolution flame as a source of ignition Airsystem is drawn through bottom unattended A vvorking gasiíier requires the the integrated sensible heat of the gas adds to the flame temperature and The calibration can be predicted from the gas properties and over a wide range of readings Commercial units are available port to permit completeofcombustion or larger operation of a number components.Smaller It is desirable to ũares have overall heatas output (Das using 1986) has been using dimensions of$10, the TIPI pipeworkshop and oriíice formulas for as low dualrange vertical inclined manometers can be built on this principle, or commercially available automatic Controls and vvarning systems on production updraít producer gasand from high-resolution wood chips to manometers fuel a melting given here in more detail in start at $30, and stationary can burners and incinerators used gasifiers in gas order to keep can the be System in balance íurnace, melting copper and bronze at high efficiency using chemical engineering texts and cost as much as $400 Special handling is required to avoid and to warn the operator when a parto lb wood chips per pound of bronze poured and a rapid 9.4.2 Burners handbooks, such as thefluid Chemical losing or blowing out gauge because Engineers’ of excessive ticular component needs attention Although such a degree of heat cycleAccurate (20(Perry to 30leveling min) toThe reach pouring Handbook 1973) location of temperature pressure taps on an Close coupled gasifier burners offer improved clean, high pressure is important for all manometers automation would have been impossible to implement on the oriííce meter will signiũcantly affect the calibration For an efficiencyofburning of solid fuels compared with conventional The flame insidedifferential the forge ispressure very different other gasiíiers World War II, reliable, in- expensíve sensors, Diaphragm-type gauges from give any a needleaccurate measurement, the oriíice meter should be calibrated solid burners Gas-air mixture and mixing are more easily kind of reading wood burner It has the pressure intensity They and fury of a jet Instruments, and Controls are wide- ly pointer of the differential are available against a primary Standard suchílarae as a Pitot orquality dry gasfuel test controlledtothan al solid fueldue burners, engine and the clean invisible of a tube highavailable dayareinconventionmuch of the world, largelyresulting to the in full-scale accuracies of 2% and full-scale ranges from 0.25 meter Although small deposits of tars will not plug the in more complete combustion Equipment costs for Direct of producer gas lends itselí to a by wide range development of the modern automobile and solid- state to 150 combustion in water gauge (e.g., those manuíactured Dwyer) HEMISPH meter, they may alter theceramics, calibration; írequent cleaning or retroíìtting an existing gas or oil unit for close coupled of applications (e.g., glass, steam, drying, technology These gauges are rugged and can be used in all positions vvith ERICAL recalibration may beprocess required To prevent íouling from char or TIP gasiíying are generally less blacksmithing, and heat) positive and negative pressures This chapter deals with the methods and equipment that have condensate, the orifice opening may be moved to the bottom been used to measure each physical quantity critical to Forthe nondifferential in excess of aand few pounds per of pipe to permitpressures free passage of solids liquids optimal gasiíier operation Since these measurements are square inch, the well known Bourdon gauges should be used Calibration is advisable against a Standard HOLES, 0.04 in dia EQUALLY SPACED AND commonly used by chemical engineers, the reader is reíerred oriíice meter or other known Standard BURRS to chemical engineering texts, and especially to handbooks If the gasiíier uses a cyclone, then it can be used as a SECTION such as the Chemical Engineers’ Handbook (Perry "A-A" convenient flow meter by locating temperature and pressure 1973) taps at the cyclone inlet and outlet Calibration again may be 10.2.2 Gas“s” Flow Measurement dirty gas The type Pitot tube shown in Fig 10-2 is more Chapter Pitot 10 Tubes The I STATIC PRESSUREpredicted from gas properties and cyclone dimensions or Gasitier Instruments calculated against a known Standard INNER TUBE s is related to pressure by the equation 10.2.1 Pressure Measurement 1/8 in o D X 21 B &Flow ỉ In experimental work, pressure drops may be measured ' GA TUBINGQ = K'\j^ặ °G=aD ^[^° G routinely across the gasiíĩer bed, the oriíice plate flow *1029 cm water = atm; 406.8 in water OUTERTUBE gauge = atm; 26.4 in water = psi Fịg■ 10-2 “S"-type Pitot tube for dirty gas (Source: ASME 1980, Fig 1-1) 5/16 in D X 18 B & s 10.2 (10 2] Fig 10-1 Standard Pitoỉ tube (Source: ASME 1980, Fig 1-1) 100 Handbook of Biomass Downdraft Gasitier Engine 98 Handbook of Biomass Downdraft Gasitier Engine Systems Systems Instrumentation Instrumentationand andControl Control101 99 FR Table 11-2.facGasitier For a 55-mph cruising speed and a fuel-conversion tor of Size versus Engine Output cylinder-wall thickness is inadequate to accommodate Optical pyrometers can be used from about 300°c (in- írared) 10.4 Computer Data Logging and cylinder-wall sleeves, limiting the number of atimes that the Imbert Throat Stratitied Hearth or 700°c (visible) to 4000°c They require viewport and b c Chapter 11 Capacity Diameter Diameter Thermistor, consumption bimetallic, rates for various and sizes thermocouple of liquidfueled switches engines and light-block engines can be rebuilt T = calibration temperature Control Power p Consumption Q (kBtu/h) (cm) (in.) (cm) (in.) are generally hand-operated They are useíul for spot-checking (hp) (Ib/h) are shown inactivate Table 11-1 controllers a switch closure in response to high- or 100 200 1400 16 40.5 very sophisti16.0 suríace Today, temperatures low-cost computers can exercise cated Engine Adaptation Operation 11.6.2 Small6.3 Engines TQ = operating gas inletto temperature Qcorrective =and flow rate low-temperature conditions either take action or control over most processes in response tobest suitable signals, as 50 typically require100 700 11.3 4.5 29 11.4 Gasifiers about 10 kg (22 lb] of wood or Of these methods, thermocouples are suited to Engines suitable for long-life operation (2000 to 20,000most h) giveKvvarning signals overall calibration for specific flow meter can be seen under the hood of any modern car.availComputer data 25 50 350 Thus, 20.5 8.0 kg (11= lb) of charcoal to replace one gallon of gasoline gasiíier measurements Thermocouples are able with must have an air cleaner, oil-pump pressure- lubrication, an Producer gas recording and or control be considered in any research 10 140 analog 2.0digitalshould 13 5.1 generalthermocouples for20 ratio and geometry (from it isa = possible toconstant calculate wood consumption rates íromthe either readouts, and the signal can be Additionally, andd/D thermistors generate analog oil íilter, and thermostatic enginetemperature regulation 11.4 Gasiĩier Types Suitable for 11.1electrical Introductỉon 10 70 3.6 1.5 3.6 cost and development program and for any commercial gasifier Fig 10-4) data in Table 11-1.which In addition, the maximum gasproportional production recorded electronically Analog thermocouple meters may signals, can be used by suitable Smaller engines of the air-cooled splash-lubrication types Shaft-Power Producer gasgasifiers technology is useíul to maximum provide hearth clean from is deteriĩiined by the as as $50, engines butGeneration theỵaverage require a fixed lead resistance controllers ApImbert =(2.2 pressure drop across flowismeter (e.g., many manuíactured firms suchThey as kg Ib) of wood required per hp-h for alittle 7000-Btu/lb fuelby heating Legend combustion heat,0.9shaft and is electricity load—typically Nmpower, /h of gas producedfrom per widely square are used widely in pottery and toundry tradcs Digital VVisconsin, Briggs, Honda, Tecumseh, and Kohler) have very Updraữ and fluidized-bed gasiíiers have the slowest response value (Gengas 1950) Cable Gasoline choke D = pipe diameter available biomass fuels Historically, engine shaftway, power centimeter ofinside hearth area (see Section 5.8) In this the pyrometer readouts start betvveen at cannot $200.oilbe They read (one short Service periods changes smalltimes of the gasiíier types and ex- pected follow Air control lmbert throat constriction diameter is given by D = 1.6 VP~cm toto greater Gasoline generation has been given the major application of hearth small size, gas power requirements above determine the precision than analog, and due to their high input impedance, engine mechanic recommends an oil change every hboth of dmaximum = oriíice diameter valveload of hmax changing loads with favorable results The gas from carburetor A stratitied bed hearth = MBtu/h-ft is typical for wood producers Large producers, onTable the other hand, madeof valve “town as 10-6 in Table 11-2 5-1 for other lead length isThese not critical sizing Gas Gasoline throttle operation) engines are gasifiers designed for life spans of Fig Herschel-type Venturí flowmeter (Source: Ap Perryfor 1973,a Fig 5-13.© 1973 Used updraỉt and fluidized-bed alsototal contains large It isshown convenient to plot QSee versus handy reference where: 10.3.3 Temperature Controls 10 hp-h/gal (a typical value for a spark engines), the fuel Wood Fuel Hearth a b C gas,” which was piped for cooking, engines requires saíety precautions gasiíier types with permission of McGraw Hlll Book Co.) lighting, andbecause heating for heating it may cleaning1000 system, and 1981] into theSome gas mixer where air is mixed around (Onan oítheabove quantities of htars, making these gasiíìer types manufacturers unsuitable for Dimensions and calibration constants are shovra for several contain dangerously high levels of carbon monoxide so with the gas have certain models that meet long life requirements engine applications The oriíice major meter use sizes of in small Fig.producers 10-5 during World War IIa was Retaining the liquid-fuel carburetor in conjunction with gas it should be vented Heat from the for transportation, especially trucks and buses Al- though 11.8.2 Gasresponse Mixers time mixer for dual-fuel realizes the best advantages of 11.6.3 The íastest is obtained from crossdraừ gas Rotational flow pipe fittings cause serious Natural-Gas Engines exhaust gas caused canoperation be by recovered with acancompact waterPipe IDisOritice K* vehicles could become a major use of producer gas again, both fuels, saving liquid fuel for occasional full-powerbursts producers, but they are suitable only for low-tar such as metering errors It is good practice to provide at least eight Maximum power achieved with a producer gasfuels air mixture cooled heat exchanger or put to direct contact uses Larger displacement (D) in (d) in.spark-ignition scfm/in a* engines (larger than 460 especially during a liquid fuel emergency, the added difficulty while making economical use of producer gas during normal 10.2.3 Solid Flow Measurement charcoal Although low-tar operation combushas beention observed in pipe diameters upstream and three pipe diameters 10.3 just lean of the stoichiometric ratio,* as slightly Controls in ) are used for natural-gas-fueled station- ary engines, A particularly attractive fortion thecruising waste heat from of using solid fuels forapplication transportadoeserrors not make operation A War gas producer sized to provide power as dovvnstream of the oriíice to minimỉze rotational crossdraít gasiíiers, nozzle spacing ishand, very gasoline critical and load shown in Fig 11-2 On the other delivers Most World II gasifiers were batch-fed, so it was very manycommercial of which are used for irrigation applications For application, gasiíiers must be safe, Like deengines is thecompetitive drỵing of biomass íeedstock beíore using itfor in 5/16 1.75 4.47 producer withcover gasoline today If programs shown ingas Table should at least 90% of to expected variations can cause tarring maximum5/8 power with mixtures signiíicantly rich over itsa easy to weigh the11-2 biomass fuel it was fed in order record Venturi Meters The as Herschel-type Venturi flow producer gas, natural gas has a low flame-velocity and the gasiíĩer The 50% moisture contained in fresh wood chips pendable, and convenient Automatic and unattended 11/2 3/4 8.53 3.79 making synthetic liquid fuels (methanol, gasoline, or diesel) driving conditions stoichiometric combustion ratio biomass consumption However, technique resultswith insignal only meter shown in Fig 10-6 provides a higher pressure Downdraft gas producers provide a low-tar gas product relatively high octane 1rating These engines operate atcontrol afrom low can removed effectively by this drying the chips the operation, an necessity, will require suitable eventual 13.65 3.41 from be biomass or coal are successful, producer gas may never aengine’s longa time average measurẽment of thethe actual fẽed rate with minimum pressure dropisacross meter, because the biomass and also have a rapid response time, so they are rpm The engines also operate at a high compression ratio and exhaust gas There drying capacity to spare if and waming sensors and mechanisms A gas mixer behaves in some ways like a liquid-fuel be neededEngine for transportation applications 11.6high-efficiency Selection divergent downstream section are of used the meter conserves gas suited for powering engines with either varying orburetor fixed *K and a are the calibration tactors in Eq have a relatively high thermal efficiency In addition, they drying methods carburetor, but in reality it is much simpler A carMany gasiíier systems will be fed automatically, using level 10.3.1 Fuel-Level Controls Because engines are mass produced vehicles, the vehicle momentum by converting velocity for back into pressure In loads Low-tar gasiíỉers now under development incorporate have a very long Service life and are must mix the correct weight of air with the liquid fuel Because Producer the engine’s exhaust gas is hot enough (600°700°C) tomostdetermine the feed rate, as 11.2Controls Gas does for Transportation engine isthe theVenturi likely candidate for buildsmall addition, meter not present abruptingsuríaces If a gasiíier continues to operate thegas biomass has about been design changes that suited recycle oĩ the with and additional particularly to after large (greater than 250 (normally air-fuel ratio of some about 15 for gasoline to decompose biomass, it must be tempered (substantially Fig 10-5 Oríliceameter calibration íactors shown in Fig 9-1 If the change in weight between levels Transportation place a very heavy demand on systems Largerapplications systemsbecansubuse natural-gas engines, which in that otherwise would ject to impact by tars and consumed, there is a danger of damaging the highair to give even lower tar values (on the order of 50 mg/Nm kw) installations 6.5 for methanol) when the throt- tle is opened suddenly, this) diluted with cooler gases) beíore being used One of is calibrated, then recording the number of feed cycles alproducer gas sỵstems: the system must be small, lightweight, many ways so are contaminant more suitable but also are expensive particles, buildup is more and the temperature regiondowndraft of enthe riched gasiíier because of the5idling exthan conventional gasiíiers (see Chapter and mixture is the momentarily over therequired normal the best ways to dilute isloadminimal to take the lows one to estimate biomass consumption Aconditions; more ac- curate Inc.) Natural-gas because of engines amount are of precise built by machining Caterpillar, Waukesha, forchar its and compact; operate at varyinginstallation have maintenance required forwidely a permanent is reduced traordinarily high temperatures generated during especially Section 5.9) mixture by theMoline, accelerator whichThese supplies a squirtare of warm, humid gas leaving outlet ofin biomass dryer, technique involves a weighing means isthe inserted along the 11.6.1 Large-Vehicle Engines — that Truck Minneapolis andpump, others engines production fast low in the tar; cost; safe; The response cost of atimes; Ven- be turi meter is bethelow highest ofbeany of and the gasification and combustion Therefore, fuel This mixture is additionally enrichedfor at high loads by add about 10% by volume of engine exhaust gas, and recycle feed train to measure the amount of feed delivered to the Engines up to 50 kW available with Standard options industrial Sizing the Gas Producer to be to use and Service differential sure methods velocityand measurements be reduced Controls by adjusting should thetofuel-air be installed ratio to inand maintain thethe a peakfuel Theconvenient butterílypresvalve often used inofthrottles chokes has 11.5level the power circuit in gaseous order boost power tovarious protect the the mixture to the gas entry port of the dryer Reusing the gasiíier operation on fuel An optional top-oiler is presented here hoppers power mixture, and the gasiíier but this itselí requires to wam operator when exthe perience biomass level One been found to respond to adịustment very nonlinearlỵ and, Engine 10.2.2.3 Positive-Displacement Meters The largest widely available spark-ignition vehicle en- air gines engine from excessive temperatures The Currently, vehicles are beingofpovvered regularly by outlet gas some from the dryer instead using ambient to recommended, which supplies oil mist with the fuel to is improvement getting low.is thatentodaỵ’s technology might to gasiíìer Alternatively, thereíore, the begasiíier a troublesome itselí maymethod be weighed for June controlling to record both the are Big engine Lung V8 460-in engines The Ford truck engine of The positive-displacement dryforgas isbring a an primary gas mixture riched starting by the choke when gasiổers in can Brazil and thegas Philippines (Mahin, temper exhaust offers several advantages: A common problem among gasiíiers ismeter the may use of oversized lubricate the piston rings The top-oiler greatly reduce designs is automatic mixture control, employing a íeedback the gas-air entry mixture and consumption A gate valve rates provides of fuel much Flexible Ẽner connections control of this size is used industrially for stationary applications and volume Standard It measures the accumulaĩed totăl the engine is cold 1983)(1) Because Sweden hasthe maintained stockpile of vehiclegas a coming from ready the A number of level indicators are available on the market for gasiíier An oversized gasifier produces excessive tars the wear experienced with dry-gas fuels, andcontrol may be helpíul signal engine exhaust Thisover typea of isrange already on thehighly the airgasiíier inlet than are needed, a butteríly so the valve, gasifier so the can narrow be weighed power is regarded because itsthat extrareadily and flow offrom a the gasthe and isofvery accurate very widethe of gasiíiers as part ofdoes its national preparedness strategy since the dryer is already warm, more of itheavy must block be used to dilute signaling level solids and liquids in containers These because lower flow rates not develop high with producer gasback on smaller as well The producer gas engines mixer must mix a in use on feedfuel-injection systems, and it shouldbe free peakfrom is broadened thecan variable outíorces overof of one-half thefull connections to oneplans turn of the gate repeatedly be rebuilt to its original speciíications flows It is relatively inexpensive because of its use by the Suez oil crisis A handful groups offers for vehicle (and cool) the engine exhaust gas to a given tempered operate on the basis of of for light or with sound signals, bin wall temperatures necessary good tar the destruction An proper ratio air producer gas, adaptable to producer gas systems valve Converselỵ, the entire range from too rich to too lean Lighter weight engines ofNunnikthisgas displacement from passenger Large, natural-gas, industrial aabsorption quantum gas industry Numerous movingengines parts areexhibit ex-and posed to the gas, gasiíiers (Mother 1982;Measurements hoven 1984; Skov 1974) temperature Therefore, more is available for drying the pressure, resistance to vibration orpressure of 10.2.4 Temperature undersízed gasifier excessive weakgas, and approximately a 1:1has ratio of fuel torotation, air overhaul by drop, volume Variations occupiesAmerican only a Ponfew degrees of arc on converted aengines) butterAyand valve and is vehicles (e.g., tiac and Buick have lighter leap in equipment and costs so Gas-fueled the gas must buses, be clean which and necessarily dry Its main make applications ữequent are stops, in Various vehicles have been operated feedstock; more gas increases the capacity of the íeedstock radiation Suitability depends onand vulnerability to íailure from excessive raw gas temperature, may be changes prone toinburning Low temperatures (up to 300°c, 572°F) can be visually in the producer gas mixture cause sharper engine easily missed altogether a butterũy valve can be blocks In addition to a However, shorter Service life for these over the cost of vehicular engines Service parts are measuring overcome the sampled fuel-air dry problem gas in a with contaminant a bag insampling ílated with and gas for for demonstration purposes; however, regular use of these drying process (2) The humidity in the dryer flume gas clogging or tarring the device After installation, the control out the grate (See Sections 5.7.3 and indicated with mercury thermometers orandbimetallicstem dial power than similar variations in 5.7.4.] a gasoline mixture, as Fig 11-3 Gasairmixers (Source: Adapted from Cash 1942 Anon 1943)parts used satisíactorily throttle and gas-inlet control lighter engines, thefor rebuilding costs andíeedstock overhaul cangas be often available only maintains through the manuíacturer and may calibrating by a blower, other which flow meters gas flow stops The vehicles is rare (NAS 1983] reduces the chance for pyrolysis of the the should be Fig repeatedly tested to actual ensure thatduring it is íunctioning, thermometers Alternatively, ứiermistor sen- sorswhen can be used Begin shown sizing in by evaluating 11-2 For the this horsepower reason, needed the gas For more sive than for the heavy-block engine Also, thethe involve dovvntimes as as hightion costs surge we oflong power needed forwell acceleraisnotthen provided recycles to the dryer (3) Lastly, thean gas from the dryer is since seen these devices íunction for If this it isexpenessential to prevent gas from being released into in temperature range to provide electrical signal that the mixture task athave hand, must not be be misled con- byclog trolled en- or gine by speciíications the operator mostly by gas from the bag 11.3can essentially Producer engine Gas gas; for as Electric such, Power and 11.6.4 many reasons not anticipated by either the user or engine after shutdown, annonoxidizing additional gate starting procedures When the gas is less tarry and can Driving through hilly country in then ait is producer-gas-fueled be compartment used for exhaust automatic recordkeeping and/or control Diesel Engines Vehicle during producer applications gas operation seldomFlow useThe full power gas quality output A better can 10.2.2.4 Tracer-Gas Measurement tends to quench incipient firesOften in gas the the dryer manuỉacturer valve should beany used forskills positive shutoff idlingthe is support combustion on its own, the blower is tumed off, and and Irrigation vehicle requires special driverIf races purposes indication varygas during of operating is and the vehicle’s needs measured periodic Diesel engines also arehorsepower suitable for large installations but Total flow can operation be measured by injecting a small, acdesired, a metering idle valve from gas inlet the gas valveproblems, is opened Then,must the producer gasinair/throttle is engine while going in leading order buildtheup the gas Compactness and lowdownhill weight are not as to important for power íuel adịustment; economy the gasflow mixer allow for dependent have special discussed in Section 11.10 10.3.2 curately Pressure measured Controls of tracer gas into either the air or (type K) used thermocouples can be during used 11.8Chromel-alumel Spark-lgnition Engine Conversion around the throttle may be enrich the mixture slovvly ofopened; simultaneously, the flow gas- toairaccommodate mixture is quality, so that high-quality ístoavailable when climbing is and irrigation purposes as gas theỵ are for transportation control the gas, air, and mixed-gas producer gas stream tracer gas must be one not The average vehicle The engine power required from anormally gasiíier continuously to 1000°c (1800°F) andmixture, intermittently to 1200°c, Simple electromechanical switches absolute or idle, without changing the increased running asplace shown inWorld Fig adjusted to obtain maximum power that out- sense put At the same resumed Traffic accidents in Sweden during Electric power production and irrigation minimal such adjustment 11.7 Cogeneration present in producer gas, such as helium or nbutane, and may be íigured from the gasoline mileage at cruising speeds: and they provide an almost linear electrical signal of 40 | differential pressure are available These switches provide 11.8.1 11-4 time, the íossil fuel throttle is slowly closed until the War II Engine because drivers producer-gas-fueled requirements onSystem turndownof and response time vehicles of gas capable of of being measured high precision Alternatively, Cogeneration involves using part of the greater than 70% of 0A v/°c Sheathed thermocouples should al- ways be gines used in on/off switch closure signal especially at-Figs tractive, A number used inwith the past are shown 11-3 typical producer gas system spark-ignition enis changeover ismixers complete Once theAn mixture has in been initially operated those vehicles at highfor speeds while running at hills producers The gas flow required for a synchronous generator Table11-1 Fuel Consumption of LiquidPower (hp) = (ll-l) afuel gas thatNote islow normally present, such aseach nitrogen, can be energy that is otherwise lost as exhaust heat and engine connection with producer gas applications, because inexpensive, pressure differential switch is the Dwyer 11.8.3 PovverTimeLag and 11-4 that, just like a carburetor, mixer has one shown in1950) Fig The system a gasgoes producer adjusted, repeated changeovers can be made quickly The (Gengas varies over only11-1 a 3:1 ratio asEngines theconsists electricofoutput from Fueled inịected intermittently into stream, and the flow can be Cruising speed (mph) Xthe Conversion heat during engine operation If be one has a(hp-h/gal) USG for this thermocouple alloys will react with hot reducing gases, system H and Minitactor® troi (the throttle) to then meter the total flow (described Chapter a gas cleanup andfor cooling liquid fuel supply should securely closedand to another prevent full load to in no ratios load are5),normally Lean gas-air produced a short time calculated from the changes of concenừation in the product Fuel Use Rate Engine 11.8.4 Engine startup heat, then a water-cooled engine is both co, changinginthe output 8), volt-a age calibration Thermocouples Gasoline mileage at This cruising speed (mpgl control (the choke) to adịust the ratio ofofgas to air capability (descrìbed Chapter starting ina liquid-fuel consumption type dual-fuel after the throttle is opened,(gal/h) and richerblower gas Output is (described produced just Special or differential pressure transducers are (hp) gas Bothpressure ofand these techniques of from tracer-gas flow measurement convenient safe The hot air air-cooled are used vvidely in in- dustry for temperature measurements If liquid fuel is available, the engine can be started on íossil Chapter 9), a carburetor (gas mixer), and an permits rapid changeover between solid and liquid fuels after the throttle is closed This change in gas quality alters needed to produce analog electrical signals for an analog require ac- curate gas chxomatographic analysis of the sample and available a number of 5.5 During 10.0 100from fuelare (gasoline or from propane), and thesources gasiíier started engine operation, suction the gas mixture and weakens engine output to aseparately point at programmable to determine the controller, flow rate a control console, or data with a fan or blower (which may be handor battery11.0 50 of this the engine draws air may into the gas5.0 producer, the which the engine even stall The through magnitude acquisition One novel and simple alternative to a rotary blower for 22.0 2.5The blower outlet 25 operated) while the gas and flare momentary powerAaring loss can startup isstoichiometric to use the engine exhaust gas as the propelling gas *The combustion ratio is 55.0upstream from the cleanup 1.0 10tars out are located system to keep for an aspirator ejector, as shown in Fig 11-5 that fuel-air mixture that allows the gas of the cleanup stream during Fig 10-4 Oritice meter disc tactor (Source: Haaland 1968) Forfuel consumption 10 hp-h/gal gasoline a (10-2) to burn completely, with no Fig 11-2 Powervorsuagasmixturfí (Source:Kaupp1984a,Fig 198) surplus air remaining after the fuel supplv has been Engine Adaptation Adaptation and and Operation Operation 107 109 106 Handbook of Biomass Downdraft Gasitier Engine Systems Engine 102 104 Handbook Handbook of of Biomass Biomass Downdraft Downdraft Gasitier Gasitier Engine Engine Systems Systems Instrumentation and Control 103 108 Handbook of Biomass Downdraft Gasitier Engine Systems Engine Adaptatíon and Operatíon 105 The power lost awhen diesel engines are converted togiven operate leading from5 the permits air on engine generator knock, gas single-cylinder, during II areslowspeed in lubricating ability, but World it direct-inịection, alsoWarincreases cranking may allow yearsairofcontrol engineinto life).theNocrankcase known property of on producer gas is less than that lost by sparkignition flow through the engine The volume of the pulsator mixing produced The engine itselí is started and warmed up on (1000-1500 rpm) Generator Gas diesel (Gengasengine 1950).was able to run on 100% clean producer gas should shorten requirements Hand lever engines three reasons First, some diesel fuel is chamber prevents from being sucked all the diesel fuel.One As thegas producer gas-air producer for gas for extended periods (Cruz in necessarily cab engine life truck, which has been driven 100,000 Further work in engine adaptation way into the crankcase introduced; second, diesel engines operate at a higher Dirty gas can introduce tar particulates and corrosives into mixture is admitted, the governor automatically 1984) controlling km on producer X' gas without any unusual maintenance would be beneíicial In particular, combustion compression ratio; and third, diesel engines operate with the oil through cylinderblowby Particulates in the oil, anda reduces the liquidfuel feed Fuel savings up to 90% over The third method of two-cycle conversion, the twocycle problems, is shown in Fig 11-17 Ignition reliabilitỵ better with than with chamber design for isimproved swirlpilot and injection squish can lead to large excess of air, so the energy per ash and char accumulation in crankcase oil can increase straight diesel operation have been reported (Kịellstrom crank case system shown in Fig 11-10 is the simplest Mixed spark ignition The minimum eữicieninịector quantity for stable and pilot better combustion cies, Many ofthrough the clean-up engine wear Particles larger than the oil-film thickness may 1983] The governor can automatically the injection gas is drawn check valves into boost the mechanisms crankcase, where ignition and efficient combustion is given by a diesel fuelmicroprocessor Controls using signals outlined Chapter 8chamber demand ve yet to applied to scratch bearing suríaces; hovvever, char and ash tend to be te ingas the enters eventin ofthe an increased power or be a variation in the combustion through the piston mixed gas ratio oftemperature, 10 mg/kg Increasing this ratiosensors will boost from pressure, ping, and oxygen can producer gas cleanup, anduse the on gastoday’s in the motorcycles bulk of today’s test up easily crushed toGas smalleridle particles, minimizing this problem the quality of the producer gas ports Engines popular for use this power output, to a ratio of 20 mg/kg; above this injection be applied to provide continuously optimized, unattended bypass forabrasive particles are produced and production If ash slagging occurs, harder same principle sỵs- tems is far from clean enough for reliable rate, thermal efficiency falls changing with no signiíicant engine operation, to follow qualitypower and 11.10.3 at Partialoperation Load enrichment operation, Throttling much less long-life We will discuss the that could cause severe wear Small gas amounts of Flexible control cable increase Partial load operation is complicated by the fact that variations in solid fuels ef- fects of dirty gas is on essential engine lifefor in the following High compression ignition, so sections throttling sodium from ash in either the lubricating oil 11.10 Diesel Engine Conversion control a full inlet charge is required to Foot develop ignition temperature should be applied only at the gas inlet Throttling at the air or the fuel gas can lead to enginein valve corrosion It becomes cab Throttling Engine for no-loadLife operation lean outWear the gas mixture andmust Engine 11.12.2 Sticking Intake Valves which can cause bad 11.12 inlet results in excessive obvious that paxticulate removal is very important to engine 11.10.1 Diesel Operationsuction, wỉth Producer Gas (idling position and reduce the injection quantity to as low as mg/kg (Anon combustion anddusts smoky exhaust However, deposit at medium-to-high life at many levels í/> Tar mists and form an asphalt-like around the Diesel engines are operated on producer gas in the “aspirated” 11.12.1 Engine Lite Expectancy 1944) loads, where the gas-inlet throttle is fully open, the air inlet intake valve stems Valve-sticking more a air problem of l mode The with isthe intake stream Fig 11-15 Heatproducer values (Source: Kaupp 1984a, Fig E N Gtor I N Estoichiometric Sgas P E Eis D mixed , rfuel p mair mixlures E N 177) G IA NE S P E There E O r p m are reports from Sweden E N Gduring INE SP E E D late , r the World War II «1 Diesel engines alsoAccumulations can be converted completely to producer 11.12.4 Tar/Oil throttle may be partiallythan closed increase gas Sluggish suction valve pm accumulated of to engine wear small quantitydeposits of diesel fuel is in- troduced continuously era (undocumented) and also fromratio, recent investigations gas by reducing the compression adding a sparkmists occur as very íinely closing until cylinder compression Fig.G11-9 Gengas Fig gas 187) a s hPulsator edecreases aregular t i n g two-stroke v a l u einjectors 6power 9engine M J / N(Source: mto' igGas h e a t i n gisv alost land u e M J / N mTar/oil ■' G a s h edivided a t i n g v a l u droplets e M J / N much m through nite1950, the mixture (Kịellstrom 1981), ofreplacing longer engine life ex-with perienced with ignition system, and the injectors spark smaller than char and ash Therefore, they are much plugs more The valves mayThis be reconditioned andMJ/Nm cleaned, and I' mixture provide timing so-called pilot-injection mode■or diesel Gasoline-air mixture 4.1 4.1 MJ/Nm Gasoline-air producer-gas-fueled engines than with gasoline-íueled The modiíication expense is hardly justified, considering the Fig 11-4.engine Gas mixer showing idle enrichment (Source: Adapted ừom Heywood 1944, Fig 22) difficult to remove from the gas and are more likely to cause the to Service serious dual-fuel mode isreturned also usedfor occasionally with without natural gas or engines Note in Table 8-3 that cylinder wear is less on 11.11.5 mixture Other 4.1 Methods MJ/Nm Increasing successes of pilot inịection, except in situations where engine problems Tar accumula- tion does not cause wear; damage to rings and bearings Intake stroke isfuels verythe close to the heating value of producer gasair alcohol Direct-injection diesel engines are bettervalve suited producer gas with ỉabric íilter than wear on straight diesel fuel complete replacement of diesel fuel is required The Producer Gas Power P r o d u c e r g a s a i r m i x t u r e M J / N m P r o d u c e r g a s a i r m i x t n r e M J / N m ' P r o d L i c e r g a s a i r m i x t u r e M J / N m Fig 11-13 Power versus rpm compared with gasoline (Source: Kaupp 1984a, Figs 186, 187, 188) rather, it causes moving parts to stick, and plugs passages, sticking can beconsiderable corrected without a mixtures Furửiermore, diesel can be achieved 11.11 Increasing Power from for conversion to producer gas operation than antechamber diesel In the Munktell system Fig 11-8, the This technique allows a full saving in battery power for two Bolinder out of three tractors tested, shown and thatin contaminants compression should tooil 9.5-10:1 For intake valves, ratio throttle valves,beandreduced piston rings Tar deposits complete engine overhaul Hovvever, sticking valves clearly A portion of the power loss can be recovered even for a readily by simply increasing the quantity of diesel fuel to engines lower crankcase as the an heads air pump to replaced supply to at the expense of only a little extra liquid fuel Producer-Gas-Fueled Engines were also less on served wellcleaned producer gas than on air diesel antechamber diesel engines, must be become a viscous íluid at engine operating temperature; on indicate the need for a more eílỉcient cleanup system (Chapter naturally aspirated engineby increasing ủie compression normal value, levels when This can be accomplished easily pressurize gasifier supply air to the sion gas heating not onneeded the pure-gas heating value The mixedThe Roots the blower uses and engine shaftpressurized power for compresoil Pilot injection helps they the producer gas-air mixture to that ig- nite 11.8.5 Ignition Timing cooling and drying, can become a hard varnish will 8) redesign ofPower theon gasiíier for higher ratio, aspossibly shown in 11-16, advancing the a spark, and by and using the existing governor many engines The 11.11.1 Mechanisms of Loss mixer In thewith two-cycle conversion, either the headindimustcates be gas heating values areFig shown in Fig 11-15.diesel and necessarily reduces efficiency The turDiscussion rebuilders ofengine industrial Very stable and reliable has beenengines served inusing prevent or hinder engine ignition startup, or bend aobpushrod the hearth load to reduce tai production improving the intake systems Producer Producer gas burns slowly, as shown in Fig 11-6, giving it a brake thermal efficiency is higher for dual-fuel operation than íitted with both intake and exhaust valves, or the pistonA given volume of producer gas, when mixed with the correct bosupercharger uses the pressure of the exhaust gases to that for fossil industrial engines is related to pilot injection; in fact, it hasThe beenbest shown toisperíorm better eventlife of expectancy full valve seizure cure prevention (See Chapter It forfuel information onthan gasiíier sizing gas has afordiesel higher rating gasoline, so and the high octane rating is octane usually found that optimum engine it is for straight operation, as shown Fig 11-11 porting system must be isolated from the crankcase to prevent quantity of air combustion, contains 70% ofinthe energy of operate a turbine compressor, thereby recovering most of this engine speed High-speed, 3600-rpm operation is discouraged than spark ignition The power output from weakgas (e.g., through the cleaning methods of Chapter and verification of design.) power canvolume beobtained increased by increasing compression to operation isEfficiency by advancing thethe ignition timing 5ratio toThe 15 11.11.3 and Power Loss gas deposits fromcause interfering with lubrication an equal ofengines gasoline or propane mixed with into air Standard diesel inject the liquid fuel the lost energy because it may premature íailure speeds give 118 Btu/scf) canregularly, be 90% of that from straight diesel gas cleanliness using the tests of Lower Chapter 7.fuel with between 11:1 and 14:1 Increasing the compression ratio, degrees more than the advance used with gasoline, as shown relative power at any given low rpm proportional the compressed-air charge in order to startiscombustion at to acam time Based on cylinder, bearing, and The spark engine operating on gasoline achieves a thermal Similarly, the Pulsator prevents producer gas from passing Since enginesair longer are designed to withstand a injection particular commensurately engine life expectancies (e.g., engines 40% excess (Anon 1944) Minimum pilot is however, may prevent dual-fuel operation on lower octane in Fig gas 11-7 mixed inposition Fig 11-13 Full-throttle power preset relative to as theshown crank When using producer Mild the valve-sticking canor1-1/2 be wear, aenergy, tancy of 5000 hours was efficiency of life-expec25%-30% The same engine operating on through crankcase side-chamber issometimes provided, as shown combustion pressure (BMEP, brake-mean-engineoperated atits 1800 rpm may stable last years, 1200-rpmlimited by ability to Aprovide ignition at roughly 10% fuels because of excessive knocking and detonation increases in proportion to theinjection rpmtests rate, up gas toefficiency, the point gas, it “ping-sensor” is necessary toachieve advance the timing angle with reduced or by operating the engine on liquid estimated for anmay engine after “electronic extended with sotiming dirty producer gasdirect 15%-25% thermal in Fig ofthe 11-9, andprevented connected to bethelimited crankcase through The and ignition” pressure), power increases must to restoring thea operation may allow 3-year liíetimes, and 900-rpm-operation to 20% regular idle injection One method for adapting highwhere pressure drops in the intake and exhaust valves limit engine speed especially at high rpm The optimum injection fuels (especially methanol) for a short time beíore shutdown that the valves required cleaning eight times in the first 1000 depending on how well the engine is converted to producer butterũy valve and to the gas supply and intake maniíold Controls used in many late-model automobiles may be original peak-combustion pressure compression-ratiomodiíied engines to operate atana the power Beyondthatpoint, power drops offrapídly withwith timing forautomatically one engine isproviding shown intypically Fig 11-12 An engine This check tends to rinse tar movement accumulations hours 1982) gas A(Breag diesel engine using diesel achieves 30%-35% through valves The pulsating of air in the helpíul in the ideal spark advance for 11.10.2 starting Diesel Engines partial load on lower octane fuels is to recycle some exhaust Fig 11-7 Ignition advance forproducergas operation Shadedareais range of producergas increasing rpmwhile rate.timing an improperly set angle will roughlygas, at low speed into the crankcase oil, inwhere they less damage This thermal efficiency Operating on 90%run producer it can be crankcase alternately sucks and mixes air and gas, and then producer gas, permitting dual-fuel operation Fig 11-11 Diesel dual-fuel efficiency and fuel savings (Source: Cruz 1983, Fig 14.© gas back to the intake maniíold The mixture operation; solid line is týpical operating condition (Source: Gengas 1950, Fig 198) Diesel engines axe started by first igniting and fanning the 11.12.3 Oil Thickening and Contamination and expel to smoky at high speeds technique mav merely prolong the time lag betvveen repair, expected give exhaust 25%-30% thermal efficiency The overall delivers the mixture to the combustion chamber A check 1973 Used with permission of the Beiịer Institute) The volume of Plugs intake gases for exproducer gasgas useburns is roughly of gasoline, air, and haust more gasiíier with the blower until clean, bumable gas is 11.8.6 Spark and delay use of proper cleanup techniques In gasoline engines, gasoline vapors blowby to efficiency reported of the system must be ÍTom computed fromal-tend engine valve It has been that when operating lowed doubled over gasoline or propane use,conditions and partial in- creasing slowly, minimizing knock and permitting The porcelain insulator oftoa self-ignite spark pluggas, may glazedpower with thin oil with Withefflciency clean producer thebevolatile motor efficiency andtime gasiỉier producer gas-air mixtures without pressure drops reduce the peak-power rpm by up to 30% The Oil should be changed when it is visibly dirty or excesoperation íeldspar or quartz for generator gas operation, to permit easier oil fractions evaporate, causing the oil to thicken combined effects of a reduced mixedgas heating value and a sively thick Crankcase oil analyses are more widely available Engine íriction losses are primarily a íunction of engine Cam shaft design mayimproves optimized for deposit removal Spark plugs forbegasoline engines are naturallv Thickening the oil’s reduced peak-power rpm result in an overall reduction inlift, the today than in the past and can help diagnose causes of engine speed Partial-throttle operation increases the íraction of fuel producer gas by íaster valve opening, higher normally not glazed because lead anti- knock compounds maximum engine power up to 50% wear consumption devoted to valve fixed losses Theoptìmized highest shaft and no overlap, with timing-duration for form a conductive glass with engine the glaze Therefore, lead-free efficiency for any speed occurs with the highest power producer Synchronous require engine speeds gas shouldgas aỉways be used forgenerators start-up procedures with glazed 11.11.2 Engine Breathing Engine Corrosion consistent withrange complete combustion Therefore, itbeen is 11.12.5 of 1800, 1200, or 3600 rpm Cam shaft design has plugs The heat of the spark plug should be high enough A producer gas engine must handle roughly twice the primarilv thein beneíit fuel economy that Corrosive engine cyclinder wear increases with low operating overlooked soof far the lowerofrpm region to per- mit for the plugs to self-clean, but not so as tovarious cause volume intake gases ashigh gasoline techniques are used to increase the power output obtained temperatures as shown in Fig 11-18 Below 120°F, bearing preignition If fouling is encountered, use a lower heat Power levels also have been increased to engines The engine’s breathing ability thereíore begins from producer gas corrosion, cylinder wear, and ring wear rise rapidlv with number electrode) near-supercharged períormance by improving the to limit (hotter en- gine power at lower rpm The increased water condensation and corrosive hydrolysis intake system installing or peak powerthrough output, shown larger in Fig inlet 11-14,valves, operating products due to carbonic acid Bolow 185°F, cylinder and especially bygas, using tuned ram induction andoflarger intake on producer occurs atSuperchargers roughly two-thirds the rpm for 11.9 Two-Cycle Engine Conversion 11.11.4 Blovvers and ring wear depends on oil consumption and oil-film thickness maniíolds intake maniíòlds gasoline fuel.Additionally, Im- provements the intake induction system Two-cycle present gas ainspecial The power engines from producer can bechallenge increasedforto conthat Above 185°F, wear is minimal and independent of oil-film may be improved with flow straighteners after can bothto raise the gas speed attained during peak-power version producer The crankcase mustthe be propane lubricated available from naturally aspirated gasoline or (or thickness (Mahin, June 1983) Wear is maximum after a coldeach bend, shell-casting techniques to give smoother inlet output and decrease the wavs overall loss at each rate and contact withpower gas impurities Arpm number of evenprotected higher) infrom several engine startup; preheating the engine block to 120°F beíore suríaces, and carefully tuned long ram tire intake maniíolds to the most novel innovations from the enWorld War IIgas era One might ask how producer startup can minimize this wear for maximum engine life give a sharper pressure at the optimum rpm A Roots-type blower or turbosupercharger canrate be used to appeared on thepeak two-stroke engines of that time containing 150 Btu/scf can produce more than increase the pressure inpower the cylinders atmo- spheric The decrease can above be made more 150/1000ths of tointhe power of methane pressure, and thus increase the air-fuel charge A positive acceptable if one increases the engine speed containing 1000 Btu/scf The is full that Fig 11-17 Swedish truck that operated 100,000 km on reason producer gas withoutany pressure of logging psig at the intake maniíold can recover by lowering the final drive-gear ratio Full unusual maintenance (Source: NAS 1983, p 46) engine power depends on the mixed-gas/air gasoline power power cannot be recovered com- pletely by ! :i ! :i Fig 11-6 Flame speed of various gases versus mixture (Source: Kaupp 1984a, Fig 182) Fig 11-10 Two-cycle crankcase system (Source: 1950, Fig 185) increasỉng the rpm rate Gengas alone Many interesting details for converting piston engines to ! 11-8 Bolinder Munktell two-stroke engine (Source: Gengas 1950, Fig Fig 191) Fig 11-5 pipe eịector for start-up tanning (Source: Gengas 1950, 151)(Source: Fig 11-16.Exhaust Combustion pressure versus compression rntio for varíous tuels Fig 11-12 Optimuminjectiontimingforpilotdieseldualfuel (Source: Kaupp 1984a, Fig 210) Gengas 1950, Fig.output 174) as a íunction of engine speed (Source: Kaupp 1984a, Fig 199) Fig 11-14 Power Engine Adaptation Adaptation and and Operation Operation 115 111 110 Handbook Biomass Downdraft Gasitier Engine Systems 112 Handbook Engine 116 of of Biomass Downdraft Gasitier Engine Systems 114 Handbook of Biomass Downdraft Gasiíier Engine SystemsEngine Adaptation and Operation 113 Systems conditions for Table gas measurements 13-1 Typical vary Fuel wideCosts ly for indicate (Diebold Various the 1986) sources Forms Diebold, of of gas Biomass Scahill, measurement J.w., (1986 and conventions Evans, $) R.J., (Chern Loosen 1985) clothing Chern, around Shyh-Ming, the neck and The throat, Gasi/ication and check for of 13.5.2 bogen) gas (0vegetation, +of 7% C0 )J.p., or pure oxygen, with two face All equipment should be checked as being of •fast-growing design life of the equipment between overhauls or (Onan 1981) Manual for Proỹessional Wood Energy, Volume III Wood unpublished This reference is to such unpublished results (Reed 1979) Table Retroỷit 12-2 Maximum Proceeđings Carbon Monoxide ofa Concentrations in Work Places — 21983) 2beneíit Financial Institutions (Kjellstrom Kjellstrom, B., Stassen, H., and Canada Corp., 800 Montreal Rd., Ottawa, Canada 325; in IV, Standard ”Biomass January 21-25,1980, Conversion: Lake An Vista, Internationaỉ Fla.; “Energy from (TIPI 1986) The TIPI Workshop accompanied Books by (A effective Das, programs tor) disparities between states ItBuena is79: prudent to seek longterm remains most attractive cure (See the discussion on low VVorkshop, Tamarron, co, 3-5 March 1982, edited Furthermore, the supply of parts and Service is Fuel more 13.4.1 Value Power Produced equipment operation and maintenance Engine overhaul and wages and income to the of the local economy From 11.14.3 External-Combustion Devices steam engine also uses combustion in KIC aDirecboiler to 12.4 Environmental Hazards % graph inthe Fig 13-1 Ifexternal the gasiíier requires continual the and development costs of the initial design E engineering Reíerences International Standards depending on the organization setting the standards Since gas However, the reader should exercise extreme caution in all “The Thermal and Catalytic Upgrading of Oxygenated, the presence of an adequate airway in the throat Biomass in Commercial Downdraft masks and shoulder hamesses to free the hands of the proven design, which can be underwritten by long-term Engineers, Electric Generating Set Processing, VVorkshop on Georgia Air Gasiỷication, Institute of Technology, Seattle, WA; Atlanta, Feb replacement Beenackers, A.A.C.M., Producer Gas 1982: A CoìỉecConference, Biomass andearnings Wastes Estes V,” Park, Ịanuary Colo., 26-30, October 1981, 18-22, Lake Buena 1982 publishes a number of books dealing with gasiíication Write of (IGT íorest 1984), management Vol and reíorestation (Kaupp 1984a) Form power purchase agreements only when and Shape where buyback Cost Cost by T.B Reed and M Graboski, SERI/CP-234-1590 Solar tar designs and drying in Chapter 5.) limited, usually only through dealers investment also may be retained in some local 30% to 70% of the value of electricity sales could result in -2 0.031 mg/m ppm Year If a gasiíier/generator system is being íinanced, investors Appendix produce high-pressure steam for piston or turbine steam Chapter PURPA requires touse Fraction buyinthis back povver ofa monitoring by aUtilities skilled attendant, cost introduces Chapter 13 (Reed 1986b) Reed, T.B., “Moving Bed Air andgenerated A of external-combustion devices can produce power The problems of gasiíier tars have been 12 ovariety oenvironmental o i 183, ($/ton) ($/MBtu) properties can be measured to aR.p precision considerably finer conversions using the term "scf.” If co the gas measurement Primary Biomass Pyrolysis Oil Vapors,” in Proceedings rescuers The Karbogen gas removes as much as Oxygen three Gasifiers, Service contracts Masters and warranties Thesis, Kansas for State prime University, power Specifications 1.75 to 1000 kw, The Onan 1979, SERI/TP-49edited by T B.Fuel Reed and D Jantzen, Ga., 1980 tion ofPapers Producer Gas With Vista, Fla.; “Energy from bỵ Biomass and Overend, Wastes VI,” January T.A for list of current toto TIPI Workshop Books, P.O Energy Research Institute, Golden, Colo., 1982 rates are ỉavorable •Proceedings If the person isgas unconscious, administer artiíicial respiration the value of the produced economies Inedited such cases, virtually all the expenses of local wages in addition toon earning aM.J., 15% return on equipment and the financial community Hemoglobin will require aCo-Current com(%) plete 13.3.4 Conversion Efficiency and engines (Groeneveld 1980a) Groeneveld, The from biomass atpower apublications price equal the utility’s full, avoided signiíicant economy-of-scale íactor against very small Biomass,” in Proceedings of the 1985 Biomass from producer The Stirling-cycle engine uses an external discussed in previous sections As gasiíiers come into wide than the error introduced by a misunderstanding in Standard conditions are speciíied or be saíely presumed, Removing excessive quantities ofcannot biomass from agricultural times as the fast as not pure oxygen alone since the C0 Karbogen of 17th Biomass Thermochemicaỉ application 1985 Corp., 1400 73rd Ave NE, Minneapolis, Minn., Solar Energy Research Institute, Golden, Colo., 1979 in Emphasis on Applications in Deveỉoping Milne, 25-29, 1982, and Lake L Buena Mudge, Vỉsta, Fla.; Elsevier, “Energy 1985 from Biomass Box 84^ Allenspark, Colo., 80510 immediately $0-20 electricity generation may generate local investment (McGowan 1984) Personal Communication, Units and T Conversions McGowan, assessment of the project with períormance guarantees and Saíety and Environmental Considerations Consumption Wet chips from tree Service Chips with twigs and bark $0-1.25 MovingBed Gasiỷier, PhD thesis, Tvvente Univ of (Strauss 1975) Strauss, w., Industriaỉ Gas Cleaning, CL>3t for generating power Plants with excess capacity the cost of ash and tar disposal aíter cleanup systems heat exchanger and combustion The main Thermochemical Contractors’ Australia 55 50 1973 8corabustion Decision use again, there will beofexternal angasincreased demand for value wood and When producer gas isConversion available, externalIf sale of1985) power to Utilities is being considered, itMaking is im0.023 conditions, expressions volume and heating must then gasclean heating value is subject to 3%Reidel, uncertainty land depletes thethe soil, removing not onlỵ nutrients but also gas stimulates vagus nerve, causing more rapid Contractors’ Meeting, Paciíic Northwest Laboratory, (Aarsen van den Aarsen, F.G et al., “Wood Pyrolysis gy 55432, from 1981 Biomass, Vol 3, p 201, Dordrecht, 13.4 Cost Beneíits Countries, Producer Gas Coníerence, Sri Lanka, and Wastes VII,” Ịanuary 24-28, 1983, Lake Buena Vista, Systems engineering should be certified by a reputable (Chittick 1983) Chittick, D.E., “MethocL for Converting (Reed 1981) A Survey of Biomass Gasiỷication, VVestern American Combustion Co., Atlanta, Ga beneíìts and risks clearly identiíied (Emrich 1985) Emrich, w., “Handbook of Charcoal Making,” (Walawender 1985) Walawender, w.p., Chem, F.M., and Fan, •Belgium Administer oxygen or mixed resuscitation gas (7% C0 in Technology, The Netherlands, 1980 Published by Krips Repro Pergamon Press, Oxford, 1975 may be worth considering if the exừa capacity can be sold at a drawback is the lack of widespread availability of inexpensive Meeting, Pacific Northvvest Laboratory, PNL-SA-13571, agricultural residue fuels This can have negative or devices are not necessary The efficiency with which the in gasiíier converts biomass fuel portant to measurement determine theconditions optimum size foreither a Chips gasiíier electricretail cost of buying electricity 55 50 1974 8Stockholm, other Devices for Producer-Gas speciíy the Demolition hammer milled dry with slivers 10-20 reducing tilth, water storage ability, breathing hence, íaster cooperate and C0 Char Gasiíication aWastes Fluidized Bed,” in 11.14 PNL-SA-1357, 1986 1982 gasifier It ISBN:91-86618-00-8, should be possible in The many Beijer situations Institute, to batch-fed Fla.; “Energy from Biomass and VIII,” January 30We have used 1and, atm1986 =permeability, 101.32 kPa =and 760 mm =removal 29.92 in.and Hg engineer ưsing a may be justified on the basis of a single(OSHA 1982) Standards for Working Environments Voi IOrganic Material into Fuel,” U.S Patent 4,421,524 assigned Series E, Voi of Solar Energy in the European L.T in Fundamentals of Thermochemical Meppel proíit Uníortunately, the electric utility climate for PURPA oxygen) as soon as possible; see Fig 12-1 Stirling-cycle engines The (Miles 1982) Miles, T.R., “The Preparation of Biomass for CONF8510167 A more complete report is presently positive environmental effects, depending upon the approach to (Strốm a final 1985) product Sừom,IfisE., an Liinanki, important L., Sjostrom, íactor K., calculating Rensỉelt, generation proịect the buyback rate isFla.; lowfor and the retaỉl Bulgaria 20 Vista, 17 1971 3demand Table 13-4 State utility Interest rates in theEstimates 8% toLimits 20% range place a 20°c high on leaving the bare soil exposed to erosion byOccupational wind and vvater beneíits of using renewable energy Fundamentals of Thermochemical gasiíiers Sweden, with 1983 minimal attention However, round-the-clock Power Generation Februarỵ 3,Inc., 1984, Lake Buena “Energy from 5Pyrenco 0.016 Two often-used references (Kaupp 1984a; Gengas 1950] use for a Standard pressure and a20-40 temperature ofif = 68°F purpose, in-house need If, additional uses can be found, the size, Maximum Exposure 1982, Saíety III, to SERI/TR-33-239, edited by Solar Energy Research Institute, (DOE 1982) ofU s Wood Energy to Prosser, Wash., 1983 Dry chips -was whole tree Chips, unitorm no lwigs or 1.25-2.50 Community, D Reidel, Boston, Mass., 1985 Biomass Conversion: An International buyback is one of coníusion, misiníormation, and frequent A long-term fuel purchase agreement at aexpense firm price with íefficiency Chronic co poisoning which often “sneak up” onof Gasiíication,” in Biomass-to-Methanoỉ Specialists (Bioenergy 1985) BioEnergy ’84, Proceedings being prepared with asymptoms, similar title, covering the six years Commissions the problem Selective wood cutting and use of some (Groeneveld 1980b) Groeneveld, M.J and van Swaaij, W.P.M operating E., Waldheim, costs Overall L., and Blackadder, is the w., product “Gasiíication of a several of BRD 55 50 1978 • rate Summon is high, medical then a aid prospective but not gasifier at the should be downsized of Seventeen people were killed in Sweden between December Length Wear dependent Although it our intention to present the collected data housing development (fewer than 20 homes), a moderately the economic yield of an installation For instance, 15% Good soil conservation practice requires careíul regional Biomass Conversion: An International 12.1 Introduction operation or minimal attendant labor is desired, then Agency Phone Contact Biomass andbe VVastes IX,” Ịanuary 28-February 1, 1985, 13.1 Introduction slivers I measurement inchanges our data reporting gas conventions different from common gas gasiíier may more attractive Some factors to1982, consider are and Health Administration, VVashington, D.C., 1982 Golden, Colo., 1979 Published in hard cover asshould T M.N., Reed, Consumption from 1949 to 1981, U.S (Kjellstrom 1985) International Producer Gas Conỷerence, Estes Park, Colorado, October 18The PURPA law does not clearly deíine avoided assured supply (multiple sourcing is preíerred) be 13.3.2 the victim, cause him2nd to become tired, uncomíortable, and Calculating Energy Costs Workshop, Tamarron, co, March work on ona$1000/kwinstallation oxygen gasiíìers at SERI and SGI ofa World Conỷerence, Goteborg, Sweden, Ịune Czechoslovakia 30 26 1976 4.5 (Chrysostome 1985) chrysostome, G and Lemasle, ]., residues (Evans 1984) imEvans, prove R.J., the íorests Milne, and T.A., fields and Indiscriminate Soltys, on ^oil “The Design of Co-Current, Moving Bed Gasifiers Fueled by efficiencies, Biomass in the including Mino-Process,” those for in drying Biothe Energy biomass, ’84, operating edited If, leavhowever, ing the the victim buyback unattended rate is3-5 high enough, the decision 1939 and March 1941 because of careless gasiíier operation within a can consistent of acceptable metric units, this 11.14.1 GasTurbines Densitied biomass (pellets, Unitorm cubes sized industrial complex, or a40-60 good-sized farm 2.50-3.75 interest costs 2.5ẹ/kWh in interest \framework í development I 0.008 determination of maximum acceptable biomass removal rates, Conỷerence, Estes Park, Colo., October 18-22,1982 automatic operation may be more suitable “Energy from Biomass and Wastes X,” April 7-11,1986, VVallace practice The following table is provided to During the emergency of gasifiers during World sale of excess electricity and cogeneration editor, Biomass GasiỊication:Principles and Department in = 2.54 cm of Energy, DOE/EIA-0341, 1982 Con/erence, 19 March 1985, Bandung, Indonesia, Edited Gasiíỉers are technically practicable But other criteria also 22,1982 Proceedings edited by R.p Overend, T.A Milne, and Alabama PSC 205-832-3421 costs and leaves interpretation to the individual states, with secured as critical to the project’s success The cost of in energy from biomass should be compared with the irritable, and also induce sleeping difíiculty Sex drive (OTA 1980) Energy from Biological Processes, OTADenmark by T.B Reed and M Graboski, 40 SERI/CP-234-1590, Solăr 35 1978 5.5 consumption “Syngas Production from Wood by Oxygen Gasiíication 21, 1984, edited by H Egneus and A Ellegard, cutting “Fundamental and use Analysis of all residues Studies,” can in lead Proceedings to poor wood ofthe lot cubes) Biomass,” Ịones, J.L and Radding, S.B., Thermaỉ the by gasiíier, H Egneus and and use of A the Ellegard, product Vol gas III, Elsevier, London, may be to choose a much larger proịect with expectations of Tidmore (Foley 1983) More recently, two researchers at a goal could be only partially achieved The still vvidespread for continuous operation Actual interest costs can coupled with cultivation methods that make best of Open thebe Proceedings editedby R.p Overend, Milne, and Keep victim warm 'Vabout Historically, producer gas has been used inuseinternalWashington, D.C., and “Energy íromBiomass (Reines 1983) Personal Communication, R Reines, War II,thevarious dangers were discovered inT.A conjunction Technology, Energy Technology •vvear Review ritỉany No 67, Noyes Cord íactor wood into decisions their use These Large criteria include ftwith long diameter 100-150 6.25-10.00 by B Kjellstrom, (To be1985 published) Judy White L Mudge, Elsevier, 1985 The equipment consist of all “home-made” comconsequent costs for all other fuels with which itheart might compete The virtuallỵ disappears, and and problems have DDR 55depending 50L irregular 1978 813-3 6Jobe, Energy Research Institute, Golden, Colo., 1982, E-micron 124, Office of Technology Assessment, VVashington, D.C., (Domalski 1986) Domalski, E.S., T.L., Jr.,or and Alaska PUC 907-276-6222 Under Pressure,” in ’84, edited byall H.2permits, Egneus Automatic fuel íeeding and ash removal require additional Elsevier, London, stands, 16th and Biomass soil depletion Conversion ofmay Soỉiđ Biomass Wastes, ACS 1985 All making zoning money questions byBioEnergy should selling be resolved, power and Certain Midwestern university died from co inhalation when they use oferosion, English units did not inTherinochemical all1UCI1 cases allow 1determined (micrometer) =(Lowdermilk 1urinary |j.m = 10" m from either the equations in Table the biomass left on the field 1975) • Drying Keep the efficiency victim varies under widely, surveillance, on as the equipment Mudge, Elsevier, 1985 combustion piston engines of both the spark-ignition and and Wastes XI,” March 16-20, 1987, Orĩando, University, London, England, 1983 mueptỉi [-» of gasiíier operation These dangerous areas were divided into Data Corp, Park Ridge, N.J 1981 gasiíier application, the avaỉlability of suitable equipment, Jim Apperson Õ ponents, all individual purchases of manuíactured parts, a Finland 55 50 1972 convenient fuels (electricity, gas, and oil) are raore expensive I 1 been common Memory and eyesight may be temporarily Arizona ACC 602-255-4251 Milne,T.A., ThermodỵnamicData 1980 and A Ellegard, Vol III, Elsevier, London, equipment (LaFontaine The 1984) necessary Personal materials Communication, and equipH ment LaFontaine, and Conversion Contractors Review Meetỉng, (WESI) WESI Engineering Bulletin WE12832M, VVaukesha, Symposium Series #130, Am Chem Soc., VVashington, d'c., system licenses, and sizes approvals may acquired be allowed more favorable climbed inside of a gasifier fuel bin transíer of the reported data to metric (Miles 1983) Miles, T R and Miles, T R Jr., “Biomass Municipal solid waste Very irregular shape with high-ash, Credit Credit graphs in Fig 13-1 The sensitivity of the generating cost to design (Susanto relapses and 1983) heat often Susanto, source occur (see H., Chapters Beenackers, and A.A.C.M., 8) A typical and fuel van diesel-powered types Accordingly, these engines remain the Fla (Bowen 1978) Bowen, M.p et al., “A Vertical Bed Pyrolysis “It is essential that a careíul survey of available sources of toxic hazards, and fire and skin burn hazards In addition, we (ACGIH 1982) TLV’s for Substances and Phỵsical biomass fuel availability and fuel-source reliability, Dana Nixon 280 Hungary 30 26 1974 4.5 40 80 120 160 200 240 combination of “build and buy,” or a tumkey purchase than the solid fuels (coal and biomass) Furthermore, impaired More extensive mental symptoms may occur, Arkansas PSC 501-371-1792 (Reed 1982) Biomass-to-Methanoỉ Specialists forBiomassConversion and Waste Incineration, 1985 reliable The Biomass Controls Energy Institute, can add 1995 to the Keỵstone equipment Blvd., costs Miami, on a Portland, Oreg., May 1984 17803 s Santa Fe Ave., Compton, Calif., n.d 1980 (Risslerarea Personal R.an Rissler, Missouri buybackW.P.M., rates; this thereíore should beConversion,” explored For instance, Erosion is1984) more destructive than drought because erosion units The for internationally established gram (g), meter (m), Preparation for Thermochemical inlb/hplst (OTA 1984) U.S Vuỉnerabilitỵ to atm Oil Import Volume compressible (1 dry) engine life, fuel cost, and labor isgas indicated in graphic form in consumption Swaaij, “Moving wood with Bed 20% Gasifier moisture with is Interroughly nal 2Recycle Liability insurance should composition major of interest atCommunication, present -(0-20) However, the -(0-1.25) gas turbine biomass and analysis and existing System,” Solid Wastes and Residues ACS Symposium Series, John Quinley have Exertion sincefuel, presents recognized two proíoundly potentially effects effects on that CO regulations, operator availability, cost and Agents in Work 1982 The American C y lEnvỉronments i nthe dG e r - be v vof a available l l alternative t55 e mKajpak, pdangerous eand r a damaging t uand r eof (uses °assured Ccourse )mixed CO occurs widely incosts our industrial civilization in delivery small Italy 50 1975 (Jasas 1982) Jasas, and J “Gas Turbine Money, the availability of suitable equipment, use of the Caliíornia PUC 415-557-1159 reliable infrastructure is available for transport and including impaired memory, reduced concentration and Workshop, Tamarron, co, 3-5 March 1982, edited SERI/SP-271-2839, Solar Energy Research Institute, Golden, one-time Fla., 33181, basis 1984 The of automatic material handling can Gasification, Inc., R.D 3,permeability Box 198, Californía, Mo., 65018, some states offer full retail value to(SI) renewable electricity destroys the soil’s water Typically, 99% of second (s), and joule (}) system is thereíore ocVVorkshop ort 1958) Curtailment, OTA-E-243, Office of Technology (Cousins 1983) “Some Properties Carbon Black from Wood (Fisher 1983) Fisher Scientiíic Company, 1983 Supply Work, L.T., “Size Reduction,” Industrial Fig 13-1 A long-term power sales contract should be in place, with a (Guzdar 1982) Guzdar, A R and Harvey, A c., “Feeding hEuropean of (3 lb/kwh) Pyrolysis (Gengas Gas,” in 1950) Producer Gas 1982: Standard Measuring Conditions for Gases may be an attractive application producer gas for electric 1(Work Nm (0°C) =and 38.55 scf (77°F) = for 37.32 scfdecisions (60°F) competing markets of fuels, be carried prior toA Mike Homeac No 76, p 94, 1978 our poisoning íinancing activities victims can have First, onthese the increased environment, exertion and inweout creases shall point the Coníerence of Government Industrial Hygenists, P.O Box Refuse-derived fuel Irregular shape, more 0-20 (0-1.25) Japan 55of 50 quantities Smokers 1975 typically inhale concentrations 8inexpensive of several Demonstration of Pyrolysis-Derived Fuels,” in composition Colorado PUC 303-866-4300 equipment, and local talent enter into affecting of electricity, gas, and oil, and reliable, perseverance, possibly brain damage The effects of by T.B.New Reed and M Graboski, SERI/CP-234-1590 Solar Colo., 1986 be compared with the expected savings in operator labor costs 1984 projects under certain sizes rainỉall soaks into healthy soil, but only 50% of rainíall may casionally Fig 11-18 Engine replaced lifeZealand versus cylinder by units wall temperature that may (Source: be more Kaupp 1984a, familiar Fig 211) and Thermochemical Processing of Biomass, u Assessment, Washington, D.C., 1984 Gas,” Ịournal of Science, Vol 26., (LaFontaine 1987) FEMA/DOE/Martin Marietta Contract Cataỉog, 711 Forbes Ave., Pittsburgh, Pa., 15219 and Engineering Chemistrỵ, Vol 50, No 3, = 37.90 scf (68°F) levelized power-price or fuel-cost escalator, if the project Coal and Biomass into High Pressure Collection of Papers on Producer Gas generation, since it operates at a relatively high efficiency Connecticut Research large-scale of producer gas plants.” Standard Conditions out Netherlands speed areas of that cointroduction absorption may be affected into the by 55 widespread blood stream, gasiíier as(Kjellstrom shovvn use 50 in 1973 8use 1937, Cincinnati, Ohio, 45211, ISBN 9-936712-39 thousand parts per million, and some can have DPUC 203-827-1553 Proceedings ofu the 14th Biomass equipment makeup and mix Where there’s need for an more predictable than MSW is available for their use Biomass in as the chronic co poisoning may go undiagnosed or be attributed to Energy Research Institute, Golden, Colo., 1982 using Fig 13-1 to evaluate whether tosmokers install the automatic Division soak into deteriorated soil The other 50% becomes runoff, (Breag 1982) Breag, G.R., Harker, A.C., Hollingdale, 13.3.5 The Cost of Labor more convenient todeíorestation theOperating reader Conversion ỉactors arewhich from of Aston, Birmingham, K., April 12, 1983 (Donnot 1985) Donnot, A., Reingovolo, J., Magne, p., and pp.277-281, 1983 No 98X-6446-7V to H LaFontaine, Miami, Fla Part 2, p.483,1958 includes utility buyback Reactors,” in Biomass-to-Methanol Speciaỉists With Emphasis on Applications in Developing 13.6 Other Considerations Leon Ryan (25%-35%) in intermediate sized units (200-10,000 kW) Gas (Overend 1982) Overend, R Wood Gasiỷication — Norvvay 40 35 1978 5.5 1983] Permanent and desertiíication, (Foley 1983) Foley, G.exerandtion Barnard, G., Biomass Fig 12-2.1943) Second, increases the impact of Delavvare PSC (Rogers 302-736-3233 1985) Personal Comiminication, Themultiple Buck Rogers, Thus, it Where isphysical necessary to investigate 13.2 Logistics Assessment high as 20% hemoglobin blood saturation (Kịellstrom Thermochemical Contractors Review Meeting, uninterrupted gas supply, choices may include small Unit Used Pressure absence of athe well-developed inírastructure is 1981) highly other causes by uninformed victim (Anon “Air-Gas Mixing Valves,” Automobile equipment 11.12.6 Engine VVarranty thus making the soil twice asTemperature arid with the same and C., and Pearce, D., Experimental Trials on arainfall Sparkỉgthe Handbook of Chemistry and Physics, 67th (Reed 1983a) Reed, T.B and Markson, M., “A Predictive D’Eglise, X., “Flash Pyrolysis of Tar from theReíerenc Pyrolysis of Volume noncompressible VVorkshop, Tamarron, CO, 3-5 March 1982, Countries, Producer Gas Coníerence, Sri Lanka, ISBN:91District of Columbia turbines can be started and stopped in a c.short time, so they (Miller 1983) State oỷtheArt SurveyofWood Review of Recent Canađian Experience, National (Cruz 1983) Cruz, I.E., “Developments in the Design of Gas Poland 30 26 1976 4.5 (LePori LePori, w A and Parnell, B., Cleanup e of already threaten much of our planet, can be initiated by Gasification in Developing Countríes, Earthscan PSC The íactors considered in this chapter directly inAuence the (Yellott 1955) Yellott, J.I., Broadley, P.R., Meyer, W.M., and co that has already been absorbed, shown in Table 12-1 Batch-fed gasifiers can be377 used inas the lowest cost system Co.,202-727-3062 1501983) Industrial Parkwaỵ, Industrial Airport, Kans., 66031, thoroughly the PURPA and State powerGasoline-íueled automobile exhausts used tostorage contain as Oct 1982, Arlington, Va., Paciíỉc Northwest Laboratory, gasiíiers or fewer large ones with attendant gas dependent on the specific situation The fact that biomass use The decision to install, invest in, or íinance a gasifier electric Engineer, Sept 1943, p scm/scf EPA Method Dry gas 760 mm = atm 68°F = 20°c (1) simultaneously accelerating the erosion process (Carter 1974) nition Engine Fueled by Producer Gas from edition, CRC Press Model Reputable for sellers Stratiíied of Downdraft gasiíier engine Gasiỉication,” systems should in Progress offer an Pine Bark,” Ịournaỉ ofAnaIỵtical and Applied 12.2 Toxic Hazards Bonnie Davis edited by T.the B Reed and M Graboski, SERI CP-234 1590, 86618-00-8, The Beijer Institute, Stockholm, Sweden, 1983 13.3 Economics Carbon Monoxide Exposure Romania 30 26 4.5 are especially useful for producing power Gasiỷication Technology, prepared by Fred c Hart Research Council NRCC 20094, Florida PSC 904-487-2740 Producer in the Philippines,” In Producer Gas Techn Rept No 1,of Earthscan, London, 1983 Gases Produced 31976 from peaking Gasiỷication March of indiscriminate producer gas (Giono 1976) use of 12.2.1.2 viability of proịect Other íactors, although peripheral, are P.M., of Pressurizing, Combustion Removing aSystems person suffering from co poisoning to fresh air designs Batch-fed gasiíiers are suitable for many situations, 1985 generation structure beíore making binding much as 5% co, and after aReport decade improved pollution PNL-SA-10646, CONF820685 has 1Rotzler, m 3doubled = 35.315 in ft“Development the =(Canada) 1000 past 10 liters years, ftto however, = 4of 0.02831 suggests m = 7.48 that galthe project in ause particular location requires aThe favorable MSW or reíuse-derived fuels (RDF) appear to be the most expensive íossil fuels because a1Publishers, boiler orkw other (Anon 1944) “Conversion of Compression Engines to Charcoal to Provide up Shaỷt Power, in engine Biomass warranty, Conversion, backed up edited with Service bỵ D Tillman conand tracts, E.c Pyrolysis, Elsevier Science B V.fuel-requiring AmsterdamSam VVeaver Standards 1982 Soviet Union 20 17 1977 Georgia PSC 404-656-4141 Associates, Inc (B Miller, Principal Investigator) for 1982 1982: A CoIIection ofPapers on ProducerGas Agricuỉtural Biomass, prepared for the USDA, Grant wood for gasiíier fuel should be introduced only in regions of 13.3.6 Maintenance Costs vvorth noting because such important considerations as bank13.2.3 Feedstock Supply and Ash Separation Equipment for A Direct Fired Coal should (Taylor Logistics be done 1986) is only as quickly Taylor, part as L., possible, the Personal equation but preíerably determining Communication, without the especially in the context of the workplace where change of decisions on an electric power proịect The State utility Controls on cars, co is still a major contributor to scf American Gas Association 762 mm = 30 in Hg dry 60°F= 15 (2) (FPRS 1983) Forest Products Research Society, inírastructure and equipment for biomass useYuen are growing assessment of the íactors that affect the practicability ofOil the Gas turbines were developed after producer use was (Johansson 1980) Johansson, E., Swedish Tests ofOtto inexpensive biomass fuels However, they are technicallỵ the already exists Inetthese cases, 3Leroy economic gas analysis is 12.2.1 Carbon Monoxide Report of the Tropical Products Institute, 56162 Gray’s Inn Producer Gas Operation,” Gas and (Roy 1983) Roy, c.liters al., “Design Construction d’un Jahn, operator Vol 4, and pp maintenance 217-254, Academic training, Press, and New conYork, 1983 tinuous Netherlands, 1985, p.14 Svveden 40 35 1978 5.5 Hawaii PSC 1loan gal808-548-3990 (U.S.) =that 3.785 = 0.1336 ftthe =ofet 231 in 1and liter =costs) Electric Power Research Institute, AP-3101, Project 986-9, Itdevice is curious no safe threshold co exposure limit was VVeight With Emphasis on Applications in Deveỉoping gas 5/9°C No 59-2481-0practicality of gasifier implementation The other part is approvals can hinge on their perceived value These (Gumz Burning 1950] Gas Turbine Gumz, Locomotive,” w., Gas Producers ASME Paper 54ABlast 201, the Gentronix, victim’s active Inc., Albuquerque, participation New If13-4 possible, Mex., 1986 the person should shiíts, lunch, and breaks serve as natural intervals forEnergy fueling commissions are listed in6th Table pollution in our cities However, until the advent of natural(Parikh 1985) Parikh, p.p., State Art Report on Proceedings oỷthe Industrial Wood Maintenance costs (as well as original-equipment More than price is involved in assessing bioíuels availability steadily concept over the operational life of the proịect abandoned, and turbines still have not been operated on and Diesel Engines Operated on Producer Gas, most difficult fuels to gasiíy (or burn) because of their high greatly simplified because the operation and economics of Road, London WCIX8LU, England, Publication VVilliam L50, ISBN 0Power, Sept 1944, pp 244-249 Reacteur de Pyrolyse sous Vide,” in Comptes Rendu de scf monitoring offuel Compressed the performance Gas ofgenerator installed Institute units thisbon 760 way -1 atm 29.92 in 68°F =economic 20°c USA 50 1979 The principal component of55 gas is IncaiIdaho PUC 208-343-3456 (Reed 1983b) Reed, T.B., Levie, B., Markson, M.L., andmmgas recognized (Dwyer 1960) during F.w the DwyerMfg development Co., and use oí8 Countries, Gas Sri Lanka, ISBN:91092-9 by Department of Agricultural Engineering, Texas A&M economics ỉactors job creation and to the American 3include Society of Mechanical Engineers, 1955 3beneíit be carried Over-exertion onofConíerence, the oflabor the rescuers should and ash removal The cost operator for reíueling can Furnaces, }.Producer Wiley and Sons, New York, 1950 pipelines, co was the primary Drummond fuelMichiganCity,Ind., component of 11983 kg = 2.204 lbProducer = 15,432 grains =part 32.105 oz (troy) Gasification of Biomass, Interim Report of50-mile DNES Forum, Forum ’82, 1983 See also previous and increase rapidly as engine size increases For instance, a Adequate resources should be available within aSvvedish (Thompson 1981) Thompson, S.P., Fuel Preparation 0.353 ft = 0.2642 gal = 33.82 fl oz = 61.02 in producer gas gas could eventually become a major Hg National Machinery Testing Institute, Upsala, Sweden, 1980 ash, heavy metal, and plastic content Joseph Gillan existing equipment are already well understood The cost of various forms of biomass should be compared 85954154-1 ƯAatelier de Travail surla Liquefaction de la Optimum-size considerations for a biomass gasiíier electric 3 Yugoslavia the maker will be the first to 58 know of the need for design 51 1971 monoxide Illinois (CO), a Beijer deadly poison that ties upXResidence hemoglobin ICC in mmmanuíactured 217-785-0326 13.2.1 Gasitier Application (Antal 1979) Antal, M.J., “The Eữects of Time, Graboski, M.S., Mathematical Model for World Bulletin War AA-2, II-era 1960 gasifiers Such auninterrupted threshold limit would =Using 0.984 X“A 10' ton (long) = 1.1023 10' tonStratiíìed (short) 8661800-8, The Institute, Stockholm, 1983 University, College Station, Tex., 1983 community New jobs can be expected because of a biomass also be avoided be determined from the equation in Table 13-3 or from the Nm NTP = STP 760 = atm dry city gas gas, coal, and 0°c blue water gas These were (Mother 1982) Personal Communication, R Sweden, Freudenbeger, (201/20/84-BM), Dept of Mech Eng., Indian Inst of subsequent FPRS symposia (available from major overhaul on Caterpillar and Onan 100-kw natural-gas Determining the economic íeasibility of a gasiíier proịect in a radius to minimize concerns for an supply The Systems a Rotarỵ Dryer, Bulletin 8006, Rader (Haaland 1968) Haaland, H.H., Methods for Determinaturbine fuel for electric power generation Turbines offer using agas commonbase Since neither moisture nor ash Biomasse, Proceedings of the 3rd Liqueíaction Experts project also should include available fuel supply, fuel improvements Minneapolis Moline has written atissues 6000-h Indiana PSC 317-232-2711 VVilliam the blood and prevents the transport oxygen to the (Ịohansson 1985) Ịohansson, K of G., “Wood Gas Engine If the is1984) toproject be burned directly, then an Boyd equipment Temperature and Pressure on the Steam Gasiíication of Downdraft Gasiíiers,” inProducer Symposium on Mathematicaỉ recognize co levels below which one could expect to beVols free Source: Kjellstrom 1981 gasifier electric Also most the operating expenses Gasiíier system application can range from asite-specific fuel or chemical widely (Bridgwater distributed and Bridgwater, used around A.v the ed., world Thermochemiare still Mother Earth News, Box 70, Hendersonville, N.c (Easterling 1985) Easterling, J.c etof al., Identiỷying the Technology, Bombay 400 076, India Voi Isimplicity in and print; II (Cruz 1984) Cruz, I.E., Gas Technology for FPRS, Madison, Wis.) engines costs from $6000 to $9000, representing more than a speciíic situation involves realistic and types (Lowdermilk of bioíuels 1975) available Lowdermilk, are also J.c., important, Conquest and ofthe there Companies Inc., Box 20128, Portland, Oreg., 20128, 198lt Every second is valuable, and the difference may have a lifetion of Veỉocity, Voìume, Dust, and Mist simplicity, long life, and reliability The of one Flow gas contributes to fuel value, biomass cost is mostly quoted in 13.3.3 Equipment Cost Workshop, Sept 28, 1983, Sherbrooke University, Quebec, transport equipment, and the PURPA climate Nm lowa Standards Council of ISSC atm dry 515-281-5701 15°c Robert Latham (3,4) warranty on a producergas-powered engine (Mahin, June Death from co is death by sufỉocation Lesser exposures Applications in Southern AỄrica,” in Symposium on comparison should be based on the cost per million Btu per Biomass,” in ACS Symposium Biomass as aOil Nonfossil Modeling of Biomass Pyrolỵsis Phenomena, from the effects of chronic cogeneration poisoning The current Pressure of biomass gasiíier electricity involve payment source for in-house or external use to a vast complex that used in many countries, evidence that co can beAgriculture handled cal Processing of Biomass, Butterworths, London, Barriers to Commercialization of Low-Btu and III in press Rural Applications, Philippines National Companỵ threefold increase in overall cost per kilowatt hour over a 50estimates of Capital, ỉeedstock, labor, should Land be Through alternates Seven compatible Thousand with the Years, gasiíier design saving effect Any producer gas installation should include Content of Gases, Bulletin WP-50, Western (MSA) Mine Saíety Appliance Catalogs 465398, 465530, moving part is unmatched Long bearing life with minimal Canada (Freeth 1939) Freeth, E.E., “Producer Gas for Agricultural Kansas KCC dollars 913-296-5468 per ton MAF ($/ton MAF), Eva where Powers MAF denotes Canada, NRCC 23130 1983) 1directly Nm = 0.632 scfm cause headaches, nausea, dizziness, and irritability co isApril an Forest Products Research International, 22 A is ofbasically only an empty can, soinert the gasiíier by hour A/hcompilation of(68°F) local energy costs similar to ppm those gasiíier Fuel Honolulu Meeting, 1of April 1979 August threshold limit value (TLV) in537°R the United States isConservation 50 coin to individuals inNo the local community through fuel produces heat and electríc energy as well as byproducts when proper procedures are 1466523, atm =Source, 1.0133 bar = 101.33 kPa = 14.7 psia 1984 ft Hg Fig 12-2 Absorption carbon monoxide in the blood (Source: Gengas 1950, Fig.and 264)29.92 GasiỊier: Proceedings of afollowed Workshop, (Proceedings Energy Research and Development Center, Don Mariano kW system and maintenance Environment costs; the value Canada the Air electricity heat in.saíely Since Information the resource Bulletin may ultimately 99, USDA attract Soil other customers, Richard Heman (5) two bottles ofỊournal mixed resuscitation (KarPrecipitation-Joy and Cox Div Anderson Samplers, Inc., 468572, Data 08-01-02-TLV Standards, MSA wear is13-2 achieved through an even, nonimpulsive bearing load 13.4.2 Cogeneration Possibilities (Perry 1973) Perry, R.H and Chilton, C.H., Eds Chemical Purposes,” ofSheet the Department of AgrículKentucky KURC 502-564-3940 moisture-and ash-free basis (i.e., AS IF the biomass had its Flammable and explosive gas mixtures are usually present (See Section 5.9.) Some gasifiers now incorporate catalysts insidious poison because it is odorless and tasteless Pretoria, South Africa, National Timber Research Institute, itself can be a very low-capital-cost device, ranging from Table gives a good idea of the economic attractiveness 1983, VVashington, D.C., Preprints of the American ìn the work place time weighted average for an 8-h work day = 29.921 in Hg = 1419 in H = 760 mm Hg purchases (including collection, preparation, handling, and Generally, the system becomes more cost-effective as exthe (Schlãpíer 1937) Schlãpfer, p and Tobler, J., “Theoretical (Arthayukti 1984) Arthayukti, w., Biomass Gasificaof the LowBtu Gasiíier Workshop, Atlanta, Ga., Nov 27, Pollution Control 78°F Marcos Ave., Diliman, Quezon City, Philippines, 1984 Arnold produced; net fossil-fuel and energy savings; and One Service, or more U.S Supt longof term Documents, contracts Stock guaranteeing No 001-000a supply 03446is 4215-C Wendell Drive, Atlanta, Ga., 30336 Inc., 600 Pen Center Blvd., Pittsburgh, Pa., 15235, n.d rotating at high speeds to establish a stable and continuous Louisiana PSC 504-342-1403 Engineers’ Handbook, 5th Edition, McGraw-Hill, New ture of Western Australia, Vol 16, No 4, December moisture and ash removed) Theclaim “waste” engine heat inof the exhaust gases and gine12.2.1.1 Acute Carbon Monoxide Poisoning inside a cold gasiíier When a (STEL) flame is is inưoduced to start and the that to eliminate the problem entirely (Ekstrom 1985) Area (Buekens 1985) Buekens, A.G and Schoeters, }.G., 11.13 Exhaust Emissions 1985 Chauviere $2000 to Products $10,000/MBtu ($40-$200/kWh) On the other hand, of a gasifier-for-heat proịect Many of the íactors discussed Chemical Society, Division Fuel Chemistry, 28, 5,toenShort-term exposure limit 400 ppm (MSA transport) and range of increases Gasifier system planning at least Directorate and Practical Studies of Operation of Motorcars on Wood tion in Thailand, National Energy Administration Min1984], Paciíic Nort±iwest Laboratory, CONF-8411156, PNLExposure perience during with pregnancy, similar systems even at Naturally, levels too costs low can show be prerequisite 4, 1975 Also the reputation of the suppliers to meet Maine PUC 207-289-3831 lubricant film York, (Das 1985) Das, A., Contaminant Testing Method for 1939, pp 371-415 (Heywood 1941) Heywood, H., “Loss ofgeneration Power inPetool block coolant from to 3/4 of the energy (Nandi 1985) Nandi, s.p and Onischak, M., “Gasiíication of gasiíier, 1973 care carbon beGasiíication,” exercised to in prevent explosions Others employ a represents high degree of tar2/3 recycle to crack “Modelling ofBiomass Fundamentals of levels in ambient air Mini (Peeper) co models I, power II, and III aVelocity gasifier system for generating process heat or may for power generation will also apply to heat Creosote The of monoxide poisoning areEnglish shown in 1983 ACGIH [OSHA 1982]] The international standards are Carbon monoxide exhaust emissions from a eventually properly running 1SA-13123, msymptoms =originally 10.76 ftshould =published 1550 in 1.30 yd (Kadyszewski 1986) Personal Communication J 12.2.2 should consider systems that are larger than needed for Gas,” in= 1937, translated to bỵ H istry of Science, Technology and Energy, Bangkok, Thailand, April 1985 symptoms measured in by the bỵ using mother, low-cost may aữect and development no-cost burnable ofWoods,” the fetus, wastes commitments should be thoroughly verifíed (As the Maryland PSC 301-659-6021 Paul Daniel Biomass Gasiỷier Engine Systems, TIPI Workshop, (Lutz 1940) Lutz, H., “Die Verbesserung des Fahrzeugscf Saturated with vvater 60°F (6) supplied the fuel Using this waste Engines Running on Producer Gas,” Engineering, Jan 24, Chars Obtained from Maple and Jack Pine in Proper precautions include the following: the tar thermally (Susanto 1983; Groeneveld 1980b; Kaupp Thermochemical Biomass Conversion: An ANSI Standard Z132.1 for (Peterson 1965) Peterson, C.M and Whitby, K.T., “Frac(MSA (Gengas catalog 1950) nos Gengas: 465398, 465530, Svenska and EiýarenheterPran 466523, with ranges cost two to Reed, eight times this amount, depending onment, the Although gasiíiers usually convert less than 0.1% 1ctua Table 12-1 shown in downdraft Table 12-2 Atmospheric concentrations above 1% producer-gas-fueled engine can be expected to be Turbines now in use operate with intake gas pressures of 75 Kadyszewski, U.S Agency foron International DevelopThe cost of athe gas producer and the cleanup portion of the internal use (with seỉl offincrease of surplus product) andinherently systems Fuel Charge Div Stassen in 2nd International Producer Gas 1984 Biomass Cost ($/MAF ton) = — ^ Cost (13-1) (Reed 1984) T.B and Levie, B., “A Simpliíied Model of lower (provided its birth they weight, are available and a the reliable risk of basis], abortion low-cost and reliability of supply diminishes, the size of the biofuels Massachusetts DPU 617-727-9748 14.73 psia (Edrich 1985) Edrich, R., Bradley, T., and Graboski, M., “The P.O Box1939-1945, 84, Allenspark, Colo., 80510,1985 Holzgaserzeugers durch Wármetichnische Massnahmen,” Table 13-3 Sample Calculation of Electric Production Costs heat from an (cogeneration) allows abecause much ofengine Thermochemicaỉ Biomass •gasiíier 1941, Always pp fan 61-63 a tars cold gasiíier before igniting it, toíabricating remove gas caloriíic value 1984a) International Conference, Estes Park, Colo., October tional Efficiency Characteristics of Donald Unit Type Cyclones,” of Aren 0-100,0-500, and 0-250 Stockholm, ppm, respective1950; ly) Translated indicate co as auxiliary equipment required, including of the input into and oils, these heavy products still (10,000 ppm) CO may cause unconsciousness only amust few 1Fundamentals lower m/s =than 3.281 emissions ft/s =no 3.6 from km/h gasoline= 2.237 íueled engines to 150 psi Converting existing turbines to producer-gas use (1 -gas) M - in A) Hearth Load (for 130 Btu/scf Arlington, Va., 1986 system primarily should be the cost ofJohns providing cogeneration Conỷẽrence, March 1985, Bandung, Indonesia, the Stratified Downdraft Gasiíĩer,” inmph The International Michigan PSC 517-373-8171 stillbirth equipment There options, are renewable indications energy that CO tax causes credits, mutations reducedstorage increases.) (ASHRAE1981) ASHRAE Handbook First aid treatments for co poisoning follow Gasiíĩcation of19 Ponderosa Pine Charcoal,” inthatdays, FunATZ Automobiltechnische Zeitschrift, No 23, higher degree of energy utilization and is sometimes eligible Conversion: An International residual producer gas; in this way, one ensures the 18-22, ASHRAEỊournalv ol 7, p 42, 1965 (Das 1986) Das, A., The authors have had more than 10 years’ levels, Generator while model Gas: IV The (MSA Swedish catalog no Experìence 468572} indicates from be scrubbed from the gas and disposed of In earlier minutes (Heywood 3cycle 1944) operating Heyvvood, H., Tests Stuart on 2pressures Mitchell Transport maximum power is achieved from a mixture that is lean of the would require the gas producer at up to fuel storage bins 0°c = 32°F these units from sheet, plate, bar, and tube stock As the Kjellstrom, ed., to be published For Minnesota example at $1,000/kW equipment cost, 15% interest, PSC operating at 80% duty 612-296-8662 Molecular vveight 29.92 in Hg = 101.325 Bio-Energy Directory and Handbook 1984, edited (7) Other methods for disposing of these materials depend on the 0.9 Nm /h-cm = 537 sc£m/ft = 3.73 scfm/in = 4.2 MBtu/horofFundamentaỉs, rate cancer íinancing, (Kjellstrom automatic 1981) operation, andOctober reduced maintenance (Kaupp 1984a) Kaupp, A and Colo., Goss, J.R., State-of-theAmerican of Heating, damentaỉs of Thermochemical Biomass 1940, pp 589-595 13.2.2 Equipment Selection Factors for additional tax credits •they Move the poisoned person to the open air room free ofand Conference, Estes 18-22, 198£ gasifier contains only fresh air 1982, Proceedings edited by R.p Overend, T.A Milne, experience inand gasiíỉcation, much of Society which isJantzen, unpublished the 1939-1945 co level by sounds M Geuther anPark, alarm (T Reed (MSA) and D These precautions eds.) by 760 13.2.4 were probably ũushed down sewer oraHovvle buried Today, Producer Gas ưnits (with Discussions), Institution of stoichiometric combustion mixture, whereas the maximum 150 psi inRegulations order toProceedings avoìd compressing theor gas for the turbine the (PNL) Annual of the Biomass Therproduction volume for a particular design increases, there Mississippi PSC 601-354-7265 Keith Standard conditions kPa mm = atm dry gas by Paul F Bente, Jr The Bio-Energy Council, 1625 Eyế St method of gas cleanup In some cases, wood chips or burnable fuel Energy drying, screening, and pretreatment systems where M is the íraction of moisture and A is the íraction of and longer overhaul cycles Artỷor Small (2-50 kW) Gas Producer-Engine ft Reírigerating, and AirConditioning Engineers, Atlanta, Ga., 12.2.1.3 Conversion: Safe An Operating International Procedures Conỷerence, Intprpct = r Equipment Cost $/kW)(Loan Interest %/yr) co _ Prevent (1000)(15) the victim _ from exerting himselí Proceedings edited by R.p Overend, T.A Milne, and L • Always stand to One side when igniting the gasifier; never (Schroeder 1985) Bỉomass GasiỊication for Electric L Mudge, Elsevier, 1985 Alf/kWh This reíerence is to such unpublished results should the Solar be observed Energy Research and enInstitute, forced for SERI/SP-33-140, the protection of 1979; all such (Mahin) practices Bioenergy have come Systems under close Report, scrutiny, Published and neither quarterEquipment needs vary with application (e.g., heat only, fuel Mechanical Engineers, Ịournal and Proceedings, Vol 151, power from gasoline is achieved by burning a rich mixture combustor Local and íederal regulations may infLuence decisions mochemicaỉ Conversion Contractor’s Revíew Missouri PSC 314-751-3234 may bethe some beneíit from harvested using Occus-biomass tom stampings, spun The size of aKaupp cogeneration system depends, oftocourse, on NW, Suite 825A, Washington, D.C., pp 379-389 filter materials are used toto íilter the 1984, tars The chips used in ash in biomass Freshly often contains Systems, Final Report USDA, Forest Service, Contract (8) int 1981 Estes Park, Colo., tober 18-22,1982 scf devices to deliver and and meter Goss fuel fed toof the gasiíier 1(80)(365)(24) atm The intent of the iníormation that follows is provide (Duty Cycle %)(365 days/yr)(24 h/day) 77° Fcastings =applying Elsevier, From look aD into saíety the standpoint, ignition opening the best while gasiíier systems aBox flame operate at & Utility Diesel Generating Units, prepared by Burns who reissued run the as risk Gengas of inhaling with index added by A Das, TIPI can nor should be tolerated ly by Mahin, International Energy Proịects, 591, Front only) well the gas and location the All 1Mudge, Btu =as 1.055 kjas =1985 252 Cal =gas 778.2 the kWh =a Jan.-Dec 1944, pp 192-208 Hydrocarbon Montana emissions also can befoot-pound-force expected toPSC begasifier lower than 406-449-2649 Ted Otis regardíng the type, form, and size of a25°c gasiíier installatìon Meeting; Edited by Paciíic Northwest Laboratory, Richland, (Davidson 1978) Davidson, P.E and Lucaw, T.w., “The domes and cones, and custom However, tooling the size of the heat load Each kilowatt this type of process can be dried and used as a fuel; if tar (Calvert 1972) Calvert, s., Goldshmid, ]., Leith, D., and a moisture íraction of 0.5 The internal ash content of most No 5339R-0-141, (March 1981] A bibliography of 800 [Reed 1985a) Reed, T and Markson, M “Reaction Velocities Proceedings editedby R.p Overend, T.A Milne, and L Gas must be exceptionally clean and particularly free from basis for understanding the elementấ entering into an Gas Energy Content negative • If the gasiíier pressure has (suction a tight-Htting gasifiers), lid, so it that should leaks be result equipped in air McDonnel Engineering Company, Inc (Schroeder, R.J., Ege, (ASME 1965) Determining the Properties of Fine the gasiíier itself Workshop Books, P.O Box 84, Allenspark, Colo., 1982 (see Royal, Va., 22630 gasiíỉer installations, however, require control systems Nebraska No Authority (NAS 1983) Producer Gas: Another Fuel for Motor those from gasoline because of thecan relative absence of The íederal government’s PURPA legislation should cause Wash These proceedings, describing work by the Andco-Torax High Temperature Slagging Pyrolysis System,” Nm Generator Gas Man costs has are always signiỄcant lived with for the spesmoke cialized, and tarssupported from single-purpose fires, and atm dry atm dry from an engine generator yields arund 15,000 Btú/h in 0°c dry (9) (Hodam 1983] Hodam, R.H., Williams, R.O., and Lesser, is collected on solid íỉlters, the íilters be incinerated If Mehta, D., Wet Scrubber System Study: wood is less than 0.01 (1%), but as-delivered it may contain papers used by authors has been prepared and can be For wood chips at $24/ton, 10% H20 + Specitic Fuel Consumption of lb/kWh, we get Fuel Cost in a Downdraft Gasiíier,” in Fundamentaìs of Mudge, Elsevier, 1985 3.6 MJ = 3413 Btu Cal = 4.187 J alkali metal content for turbine operation, because the economic decision about investing in gasiíication íacilities being with drawn a saíety into release the system valve (possibly that will causing harmlessly gas explosions, lower the H.D., and Hunt, F.E., Principal Investigators) for the Electric Particulate Matter, The American Society of TIPI 1986) (however rudimentary), íeedstock storage, feedstock íeeding 1(Makray Btu/scf (68°F) = 9.549 (0°C) Transport, National Academy Press, Washington, D.C., Nevada PSC 702-885 3409 hydrocarbons inaccessed thein producer gas The lower planners to recognize thekCal/Nm potential to be (5%] earned byNational selling ash removal U.S Department of Energy, are available from the in Solid Wastes and Residue Conversion bỵ we components, know that so these the effect of mass can be production tolerated methods in reasonable can be scf 12.2.1.4 Startup Shutdovvn 1984) Makray, Z.T., Gasification ofBiomass waste heat This heat can beand applied for such applications as M.C., Engineering Economic the tars areHampshire collected water, waste heat can benumber usedflame to Vol I, Scrubber Handbook, extraneous matter inmaterials íractions up to 0.05 Computer by title, subject, or 70°F = and > Agricultural Thermochemicaỉ Biomass Conversion: An blades operate at high temperatures and to velocities, and U.S are Potential users of gasiíiers reíerred to aSymptoms of New Table 12-1 ofquantities Carbon Monoxide which pressure the resulting equipment from a AP-3865, gas beexplosion designed handle without Power Research Institute, Project 1438-16, 1985 =should 39.98 kJ/Nm (0°C) Mechanical Engineers, ASME PTC 28,1965 (Egloff 1941) Egloff, G and Van Arsảe\l,ĩ ,The Ịournal PUC 603-271-2437 Sarah Voll mechanisms, _ (Fuel and, obviously, Price $/ton)(Specific aare gasiíier Devices for Puel/Consumption making lb/kWh) (24)(3) 1983 A companion bibliography with 421 reíerences is also temperature of the producer gas, along with the excellent energy to Utilities and then balance advantages against Technical Iníormation Service (NTIS), U.S Department of Advanced Thermaỉ Processes, ACS Symposium Series (Giono 1976) Giono,}., “Trees,” Coevoiution Quarterìy, considered We minor also know now that the smoke from wood 21.11°c Carbon monoxide gas release also occurs during startup and in a Downdraft Gasiỷier, Post Graduate Thesis at the space heating, greenhouse heating, grain drying, and absorpCharacteristics of Commerciaỉ Wood concentrate the tars and they can then be gasiíied with the Environmental Protection Agency, EPA-R2-72-118a, 1972 residues contain 0.05 to 0.20 ash íractions, so the a gas cleanup system author Published as Smaỉl Scale Gas Producer International Conỷerence, Estes Park, Colo., October Poisoning easily eroded and coated Based on tests of a 4250-hp turbine Density excellent references for economic assessment of gasiíiers fuel = 0e/kWh Environmental Protection Agency, “Determination of Emissionsfrom harm) •Symptoms A flame rather arrestor, than co asParticulate being shown expelled inRd., Fig 8-12, into the should workshop be22161 placed If the at Inst Petroleum Tech., Vol 27, p.Steve 121 1941 New Jersey BPU 201-648-3448 Gable During Physical Exertion use of the gas are also needed Combined with internalavailable from NAS ~fuel (2000 ìb/ton)[1 -(moisture %/100)] (2000)[1-(10/100)] antiknock characteristics and low prompt nitrogen content of (ASME 1969) Gaseous Fuels: Perỷormance Test liabilities Other regulations (e.g., environmental) may Commerce, 5285 Port Royal Springíield, Va., 76, American Chemical Society, VVashington, D.C., 1978 Summer 1976, pp 54-59 cooking can cause cataracts and that some tars contain shutdown Gas is released when the gasiSer is íanned or when Faculty of Engineering of Campina, Department of tion cycle reírigeration Figure 13-2 indicates a heat budget Gasifiers (Scott 1983) Scott, in D.s North and Piskorz, America, J “The Continuous SERI/TR-231Flash gasiíier Well-dried biomass fuel minimizes condensate Also available from NTIS, PB 213016, 213017, July 1972 normalization equation clearly is important in calculating Engine Systems, by Deutsches Zentrum fur Fabrication costs can be by tabulating the costs 18-22, Stationary 1982 Proceedings Sources,” edited by Coditied R.p Overend, Federal T.A.ons Milne, Register 40, Pt 60, Appendix A.Method fired with powdered coal, erosion and blade deposits were gasiíỉer operational Controls (Hodam 1983; NYSERDA 1980; EIA 1983a;PSC EIA 1983b] gasiíier the 505-827-3361 gas is mixer pressurized to prevent or ifestimated explosions there is an outlet The ílame blower, arrestor then can theof Fuel Energy New Tom Halpin Mexico 3NO At Rest combustion engines, for example, equipment add for producer gas, suggests thatSociety emissions should be lower as Codes, The American offor Mechanical Engineers, mandate use ofEgloff, particular (e.g., ash-disposal) equipment ISSN 0097-6156 Also see (IGT x62.43 1984) 1(NTRI g/cm =and 1000 kg/m = dangerous carcinogens, so they should be handled with care (Egloff 1943) G and Van Arsdell, p., “Motor Vehicles the engine is started on producer gas These two co releases 1985] Symposium on Forest Products Research Mechanical Engineering, Unicamp, for cogeneration heat recovery 1459, Pyrolysis Solar Energy of Biomass,” Research Institute, in Comptes Golden, Colo., Rendu 1982 de production eliminates the condensate removal biomass costs Entwicklungstechnologien -need GATE, Vieweg, Wiesbaden, (Pyrenco) Company Brochure, The Pyrenco Co., Box 903, (Goldman 1939) Goldman, B and Jones, c., “The Modern material (e.g., pounds of sheet metal, as well as accessory and L Mudge, Elsevier, 1985 eliminated using hightemperature cyclonic inertial cleanup, The circumstances affecting economics, however, are in These íactors are specific to the application, and they must be (2) Dictionary of Scientiỉic and Technical Terms, 3rd Ed New York: gas also will serve be under as a safety positive niter, pressure since and it will leaks plug will rapidly release when CO New York PSC 518-474-6515 Craig Indyke The of wear for a 50akW engine with 2000 hNational engine (Carré $1000 rebuild 1985] cost Carré, J et=Gas,” al., “Densified Products to be =Used gasiíiers areengine engines and gas-cleanup equipment well ASME PTC 3.3, 1969 1Propelled Btu/lb =and 0.5555 Cal/g 2.326 J/g Liqueỷaction Cal/g =Engineer, 1.8 Btu/lb by Producer Petroleum Vol International, April 1985, Organized by theburner can becost by installing propane-enriched atInlife andFurthermore, Brazil (See also, Termoquip, Alternate Energy Ltd., ƯAatelier de Travaiỉ surla de ỉar for the purpose of improving gas In this case, the gas 1984 (see 3eliminated TIPI 22 1986) quality Prosser, Wash n.d See also U.S Patent 4,421,524, Dec 1983 (Desrosiers 1982) Desrosiers, R., Pundamental Portable Gas Producer,” Ịournaỉ ofthe Institute ofFuel, hardware the íittings), tars fabrication contain phenols (based on that íactors are such potent as 0-10 None None (Hubis 1983) Hubis, M.J., Mechanicaỉ Behavior which captured of and 92% of The actual ofeachieving various forms in Table Labor Needs constant flux, and onlyT.B., general arefor noted here evaluated economically and technically eachTechnology application lb/ft lb/ft = 0.01602 g/cm =rules 16.02 North Carolina uc 919-733-2267 Tim The importance cleanup of fails leak-tight system (3) International Standards Organization, M e acosts ssystem u r99% m e20-pm nThe t a the Cof3rd obiomass, nd iCarrere t 10-nm ishown o ncannot sparticles fbeof o (Reed 1985b) Reed, “Principles and of 13.2.5 intheGas Producers,” in Symposium on Forest Products addition, electric generators and electric power conditioners 13.5 Financing Timber Research (NTRI), CSIR Conference Centre, 15, p 645, 1943 the fan outlet and byInstitute starting the engine on liquid fuel Campinas, Brazil.) ^ RebuildCost$ $1000 „ „ Biomasse Proceedings of Liqueíaction Experts can be used above its dew point, thus largely eliminating (ASME 1980) Determining the Concentration of Air Gasification Engineering Parameters, Vol 12, No 63, Feb 1939, pp 103-140 bacteriocides the length of Relatively cuts, number small of amounts welds and can bending interíere operations, with the The major pollutant source from producer gas is the necessary (Yellott 1955) The Aerospace Corporation has developed Biomass Peììets During Gasiỷication, Masters thesis, 13-1, vary from a given negative $20/dry ton Sales [depending on (Kaupp North 1984b) Kaupp, A., Gasification ofPSC Rice Huỉls: (RAC) 701 RAC -224-4078 Staksamplr Bulletin 2343-R3, Steven Kahl Bulletin of 4.187 J/g overemphasized Biomass inVolumes Advances Most individuals, minimal can operate aa G aDakota s Gasiíication,” e oíunding u electricity s Fin u e 50(2000) lGas sbe ,None ISO STD 5024-TC28, 1979 Research International — 22 training, April, Pretoria, South needed will be where is to be produced r Republic 10Ệ/kWh Pretoria, of South Aírica, 11 Volume in is 13.3.1 Costs In many cases, aMatter gasiíier might considered simply as aa During exertion, dizziness, kg/m Several potential sources exist implementing "10-20 (kW)(engine life) ■a(February ■for VVorkshop, Sept 28, 1983, Sherbrooke University, Quebec, condensate collection Particulate Stream, The American SERI/PR-2341470, 1982) Also proper and amount operation of assembly), of septic and tanks overhead and municipal expenses sewage (Perry (EIA 1983a) Energy Iníormation Administration, When a gas generator is shut off, co continues to be evolved, (Manurung 1985) Manurung, R and Beenackers, A., An Ohio PUC 614-466-7750 Alan Pound disposal of cleaning condensate, which may be high in tars, wood-fired turbine system operating at MW under a DOE landíill Colorado tipping School fees) of Mines, for 1983 landSlled burnable residues and Theory and Praxis, published by Deutsches Zentrum fur Research Appliance Company, 4215 Wendell Dr., Atlanta, Ga., (Goss 1979) Goss, J.R., An Investigation of the DownSolarEnergy, Vol 2, inC172, K.place Bôerof and J Rle Duffie, eds, batch-fed gasifíer that is not tied into other equipment Openings through which fuel is loaded should be designed to Aírica, Vol 5, National Timber Research Institute (4) Carbon ENFOR Project DDS No 41SS, KL229-1-4117, 1979 titled from Biomass and in heart and difficulty retroíit to provide gas more gasiíier project The entire system should bepounding, leak-tested upon installation Canada, NRCC 23130 Society of Mechanical Engineers, ANSI/ASME PTC 38, 1980 AnOklahoma assessment oflow-cost the overall ẹconomic íeasibility of baden, using Gasification Engineering Report, systems 1973) In In addition, Sweden there during vvill World be ash extra War costs II, for completely maximum Cogeneration: Regulation Economics and sometimes for hours Inequipment this case, itCharacteristỉcs isare particularly important The larger issues in selection areWoodgas project scope Open Core Rice Husk Gasifierfor Small-Scale occ 405-521-2335 Jim VVinters especiallỵ phenols This source can beQuarterly minimized by using the contract Initial results show that from thethe wood, though municipal waste toRules more than $100/ton for firewood delivered Entwicklungstechnologien -Canada GATE Vieweg, Wies30336 n.d Draỷt Gasiỷication of Gasiíication of Thumb — Plenum, 1985 Mechanically or electrically competent labor is requìred provide spill shields that will prevent spilled fuel from íalling Finally, it should be noted that there neither accounts nor (Humphries 1985) Humphries, J p., “Biomass Gasification,” (5) Environment Air Pollution Directorate, EPS AP.74-1,1974 in breathing may occur Practice Labor Cost for h perelectric h shitt at $5/hsuction wage rate Power and with engine Service thereaíter The pipes biomass to generate power should consider the SERI/PR-622-1348, (December 1981) and (Carter 1974) Carter, V.G and released Dale, T.toHagen Topsoiỉ and permissible automatic systems phenol and for of water was 10 Capacity Volume 1:not Regulation, Energy to have adequate ventilation Since isgasiíier no longer Oregon PUC 503-378-7998 Leon (i.e., number of1/2 uses), size, and composition equipment Application, Twente University of Technology, Box 217, driest fuels possible and using the best low tar design relatively bulky, has presented problems that were (ASTM 1977) Caỉoriỷic Value of(i.e., Gases inin ASTM in aregularly city Costs, in fact, depend on many factors, which 1984 (see TIPI 1986] Agricultural and Forestrỵ Residues, Interim where the gas is content used to produce electric power Where onto hot suríaces and possibly causing a sewers fire.Iníormation During (Singer Singer, C.J., Historỵ of Technology, Vol any evidence of damage from draining the nearly in on Porest Products Research (Rambush 1923) Rambush, N.E., Modern Gas (6) Caloritic Value of Gases inoccurring Natural Gas Range by Continuous RccordingCnlorimcter D1958) 1826,1977 13.5.1 (Reed 1985c) Government Reed, T.B., Subsidies “Role in ofspeciíìc the Carbon Form Saturation of Tax Sỵmposium approximately true Fuel Consumption Pennsylvania carrying producer gas should be provided with íittings to following íactors when considering a proịect: (Nunnikhoven 1984] Plans for Vehicle Gasiíier, Nunnikhoven SERI/PR-622 1153 (Apriì 1981) Civilization, Universitỵ of Oklahoma Press, Norman, g/m (10 mg/L), approximately 10 ppm The phenol content Administxation, Office of Coal, Nuclear, Electric, and present within the gasiíĩer, pressure builds up, and co and PUC 717-783-1373 Tim Clift origins and mix) Decisions depend on available íỉnancing, on 7500 AE Enschede, The Netherlands, 1985 watt = J/s = 3.43 Btu/h = 0.2389 Cal/s = 3.6 kj/h = 1.341 20-30 Headache may available to_vehicle prevent tarRate and condensate Ifoccur the fuel IV, installation, expected (PNL 1985) Natural ^ Caliíornia Gas (Wage Range by $/h)(Attention Continuous Recording Hours/Shift) (5)(0.5) 0.625(í/kWh include In case ofthere exertion, pressure atneed Report, Energy Commíssion pproduction 500-79-0017, 1979 automatic control is April extensive, will be additional one should install insulation, heat shields, or one million were in operation worldwide p 252, Oxfordri958 Producers, Benn Bros Ltd., London, 1923 Microíiche International, 22 1985 (Kishimoto 1985) Kishimoto, and Sugiwa, G., “Charcoal (7) Determining the gasiíìers Properties of that Fines Particulate Matter, ASME PTC-28, 1965 Thermal Conversion Processes,” in Proceedings ofl6th Incentives = purposes close off and pressurize the system to in water gauge, and Industries, Oakville, Iowa Rhode Island PUC 401 -277-3500 Doug Hartley Okla., 1980 of typical gasiíier or gas-cooler condensate is from 1500 Alternate Fuels, U.S DOE, Washington, D.C., 20585, smoke can leak out Under no circumstances should a quantities available whether X the 10-3 equipment hp eventually will be used for the cost labor of-1984) (Capacity biomass fuel kW)(Hours/Shift) is dry to Diebold, render condensate removal unnecessary, then Calorímeter, ASTM D 1826, 1977 Appears the íorehead Mild (Diebold J.p and Scahill, J.w., tive, Woodstove Reliabiỉity Standard 1(MASEC) s signaỉs 2This lb biomass =S2m scfm gas 1(computers =Proceedings lb biomass to controllers warning for workers around the hot suríaces of aofs between 1939 and 1945 (Kjellstrom copy at rEnergy Branch Library, CISTI, as a enough Soil Conditioner” Article 12-23, Vol 5“Abla(Graboski 1985) Graboski, M et1983] al., Oxygen Blown (8) Kaupp, A and Goss, J.R Sinavailable t(50)(8) aSymtbins, ein- o11.14.2 f - 3000 tfor hhp-h ecompetence -available A rthe tDumping fwith o ais lchecked land 2kwh - principal 5onto 03headache kMark W ) National G a Biomass Thermochemical Conversion South Carolina Fuel Cells (IGT) reíerence to the the entire system should be with soap bubbles, PSC 803-758-5632 Randy VVatts • (Skov whether 1974) biomass Skov, Niels is a byproduct A and Papworth, or product L The mg/L these condensates the ground or DOE/NBB0031, April 1983 generator mounted on a vehicle be driven into a closed garage exceeding immediate needs, and on the talent of the cost of the gasiíier system, including fuel storage the gas can be used above its dew point, eliminating condenGaseous Fuels: Perỷormance Test Codes, The (Nygards 1979) Wood Gas Generatorfor Vehicles, The U.S 30-40 government in thePyrolysis past has provided tax incentives Entrained-Flow Fast of Biomass,” in MidAmerica Solar Energy Complex, gasiíier Hot metal surfaces can cause nasty skin burns at Research Council of Canada, Ottawa, Ontario, KIA OR6 posium on Forest Products Research (Cash 1942) Cash, J.D and Cash, M.G., Producer Gas Downdraft Gasification of Wood, report to the Solar Headache in the torehead or back of the In case of exertion, VValter Contractors PMaintenance rDakota ofrom d uRevievv c $6.25 e r -of Ebyn Meeting, g ioil ncapacity, ehasS Pacific y $15 sPUC tused e m Northwest sutility few Final Report to USDA, Forest Service, the 11points, technical symposia on biomass energy distance that the must be hauled South 605-773-3201 especially ppm = 1sewers mg/m at íittings, valves, lids, seals.It1981 Another potentially interesting use ofand producer gas isbeto Normal for qt oil $15 13.2.6 plugs, $8 Final 1or Logistics hbiomass labor, 200 Considerations hwelds, maintenance interval Pegasus Unit: The LostArt oỷDriving Without into the waterways is not acceptable should and shut off labor fuel íeeding devices, gas cleanup systems, aanalysis, sate collection altogether This scheme been inSyngas afrom VVashington American Society Mechanical Engineers, translated Swedish Nils Nygards, available for using renewable-energy power So have some states The Proceedings ofApril, the 16th Biomass (EIA 1983b] Energy Iníormation Administration, Temperature Minneapolis, Minn., n.d temperatures well below those that will cause theTwometal to International — 22 Pretoria, South Africa, National 12.3 Fire Hazards for Motor Vehicles, Angus Robertson Ltd., Sydney and Energy Research Institute, contract head, ZK-5-05058-l, pulse increase, heartbeat, nausea dizziness,fainting, possìbly Laboratory, PNLSA-12403, CONF-8405157, 1985 (Reed 1978) Reed, T.B., “Biomass Energy A Edged organized and presented bỵ the Institute of Tennessee PSC 615-741-2125 • amount of pretreatment, sizing, drying, and storage needed generate electric power using fuel cells A fuel cell is an Table 13-2 Typical Costs of Various Fuels in Gasoỉine, Pegasus, 1974; now available from H mandatory that we determine safe disposal for these materials Beíore the first piece of equipment is ordered or financed, the recent connection, designs switchgear, Another and approach installation to condencosts sate removal is ASME PTC 3.3, 1969 PURWACO International, Minneapolis, Minn,, 1979 situation is in flux and existing situations should be checked Thermochemicaỉ Contractors’ Meeting, Portland, Cogeneration: Regulation Economics and These concerns were the impetus for vehicle gasifier glow Where possible, generators should be used outside, with unconsciousness are added Timber Research Institute, 1985 London, 1942 Systems Inc., 1985 Various íactors control gasiíier system size Since this Parts + Labor + Oil Analysis (6.25 + 15 + 8) + (5) + (15) tax benefits for biomass use (Masuda 1980) Masuda, T and Fisher, T.F., “Purox System Sword,” presented at the Annual Meeting of the International InK the Texas earlỵ days Reed, of gas T.B., generators, there were a PUC large number 512-458-0202 Mike VVilliams Gas Technology, Chicago, Colorado (1983) = °c + 273.15 40-50 electrochemical device that converts chemical energy into (Reed 1985d) Levie, B., andDas, A “UnderLaFontaine, Biomass Energy Foundation, Inc., 1995 Keystone All symptoms more pronounced, nausea, success of the project should be secured by the following: evaporation, coupled with recycling the residue to the gasiíỉer with an accountant or lavvyer specializing in energy issues Oreg., Fuel May 8, 1984, Paciíic Nortìiwest Laboratory, Energy PNL-SATypical Cost The best way to solve this disposal problem is prevention at Capacitỵ Voỉume 2: Economics and Capacity, regulations between 1939 and 1946 that required the gasmaint _ _ _ Typica adequate gasifier use Indoor would installations require Insurance should provide and Bailie, R., Hesselman Gas Generator the (NYSERDA cost 1979] of money 1980) at Site prevailing Owners interest Manuaì rates for Smaỉl document covers only small gasiíiers, the largest proịect size (kW)(maintenance interval) (50)(200) Demonstration '1980) ^ventilation Test on Simulated Japanese Refuse,” inReíuse, Jones, Solar Energy Society, Denver, Colo., Aug 28,Urban 1978, SERI Utah PSC 801 -533-3247 Douglas Kirk of(Bailie garage fires These hazards were reduced through 111.Widespread They are “Clean Fuels From Biomass, Sewage, (KjeIlstrom 1981) Kjel ístrom, B,,vomiting, Producer Gas 1980: (Graboski 1986) Personal Communication, Mike Graboski, electricity without moving parts Fuel cell standing, Operating, and Testing Fixed Bed Gasiíiers,” in Equivalence Blvd., Miami, Fla., 33181 dizziness,increased tendency (CEC “Energy from Biomass,” papers from conStill another approach applied to of an especially tarry system is More general tax breaks (e.g., accelerated 12403, 1984 lNuclear, Cost the source; indirectly other words, gasiỉiers must bethe designed to Energy Iníòrmation Administration, Office of Coal, mixer air inlet to be=(energy) extended out the engine compartment local adequate fire ventilation inspectors to that advise effectively users on changes proper precauinside tions air °R =cost °F + 459.67 1.80 KEnergy TestHydro, ing, New The York Environmental State Research Energy and Engineering, Development Inc., of interest to readers of this text is limited to a few gasifiers, Vermont PSB J.L 802-828-2880 andRadding, S.B., Thermal ConPerer version Zamore of Solid DDS-011, Solar Energy Research Institute, Golden, Colo., the of operating labor education and regulation to discourage indoor gasiíier íilling Agricultural Wastes,” Ịanuary 27-30, 1976, Orlando, Fla.; Local Electricitỵ Generation from Wood and Syngas Systems Inc., Golden, Colo., 80401 development is very active at present, and some fuel cells Bioenergỵ ’84, Proceedings of a Worìd for unconsciousness íerence, Commission of the European Communities, Brighton, ($/MBt incineration of the condensate tars outside of the gas depreciation) may exist even where no special tax privileges convert the maximum amount of tars to gas Electric, and Alternate Fuels, U.S DOE, Washington, D.C., InReport this way, the opening was a safe distance downwind from 50-60 AH-8-1077-1 to Solar Energy Research Institute, 1979 Authoritỵ Report 79-3, 1980 that supply might every not be evident to minutes to the inexperienced Alarms are available for Deep unconsciousness with increased Total Cost of Electric Generation is the sum of the above components of production cost (Diebold 1985) Diebold, J.p., The Cracking Kinetics of (Stevenson 1982) Stevenson, “Large Wood to#130, Methanol Natural Virginia Gas 0.1 MBtu/therm scc 804-786-4932 $0.50/therm Bill Stevens $5.00 each producing ahopper maximum of 20 when MBtu/day—suííĩcient to Biomass VVastes, ACS Symposium Series Am 1978 Gases inside the can flash the lid is opened “Clean Fuels From and VVastes,” Ịanuary 25-28, AgricuỉResidues, FV-80-0035/01, The Beiịer may soon available for use W.A., with producer gas Conỷerence, Sweden, Ịune 21, 1984, °F = and 1.8°c +tural 32 Goteborg, overhaul and replacement costs England, 1beNov 1980,Biomass London: Department of Energy (Graham 1983) Graham, R.G and Huffman, producer However, this approach consumes additional fuel exist for needs renewableenergy projects, and these possibilities, 20585, DOE/EIA-0421, Sept 1983 doors windows regulations applied to the gasiíier Bostwick measuring signaling excessive co Dick breathing and pulse rate Depoìymerìzed Biomass Vapors innearby aUTC Continuous Washington 206-753-1096 Plants,” inand Biomass-to-Methanol Specialists meet the of a Similar small (Beenackers 1982) Beenackers, A.A.C.M and van Swaaij, w Chem Soc., Washington, D.C., 1980 during íilling, which in turn can ignite Aammable 1977, Orlando, Fla.; “Energy from Biomass and Wastes,” Instítute, Stockholm, Sweden, 1981 Oil 6.2 MBtu/bbl $30/bbl 4.80 Elsevier, 1985 D.R., Gasiỷication of Wood in ^labor Commercial-Scale ^total ^fuel ^wear Prevention too, should be^int explored air inlet West Virginia PSCSchool of withAugust 304-348-2174 Rich Hitt Tubular Reactor, Master’s thesis,Ener Colorado (Ekstrom 1985) Ekstrom, c.,from Lindman, N., and son,EC R., (CEC 1983) Energy Biomass: 2nd p M., in Palz, w and Grassi, G., (Eds), materials 14-18, 1978, Washington, D.C.; “Energy 60-70 Deep unconsciousness (McGowan slow pulse 1980) McGowan, T.F., Bryson, F., Peterand Leverette, Concentration Downđraft Electricity Gasiỷiers, Research Paper 3412 Btu/kWh (no number) $0.05/kWh 14.60 (Reed 1986a] Reed, T., The authors have had Jennifer Fagen c 214 40 VVisconsin PSC 606-266-5620 Mines, Golden,total Colo., ^maint = 1985 + + 1-0 and + 0.625 + 0.5 = “Catalytic Conversion of Tars, Carbon Black, and Methane,” Conference Edited by A Strub, p Chartier, and G from Biomass and Wastes low breathing rate; J.T., Adeath State Demonstratìon ProgramVValkẽr in 3 from Forintek than 10 g/m years’ experience in24 gasification, of possible Coal MBtu/ton $40/ton 1.66 1more grain/ft = 2.571 Wyoming PSC much Fig 307-777-7472 13-2 Cogeneration heat budget (Source: VVESI) Dave Fundamentals of Thermochemical Schleser, Applied Science Publishers, New York, 1983 8.525 /kWh Fig 12-1 Treatment olfor carbon monoxideSelf poisoning (Source: Gengas 1950, tailure Fig 265) and death 202-232-4108 which is 70-80 Respiratory Institute Local David Morris2.00 Fig 13-1 Electricity generation costs: graphic calculators ỉor interest, wear, maintenance, fuel, and labor Biomass 16 MBtu/ton $32/ton Reliance Source: Gengas 1950 138 Handbook of Biomass Downdraft Gasiỉier Engine Systems Satety and Environmental Considerations 121 Reíerences 131 120 of Downdraft Gasiíier Engine Systems Decision Making 125 126 Handbook of Biomass Downdraft Gasitier Engine Systems 136 HandbooK ofBiomass Biomass Downdraft Gasifier Engine Systems 132 Handbook of Biomass Downdraft Gasitier Engine Systems 130 134 Handbook of Bìomass Downdraft Gasitier Engine Systems 129117 140 128 Handbook of Biomass Downdraft Gasitier Engine Systems Satety and Environmental Considerations 135 123 118Handbook 122 Handbook of Biomass Downdraft Gasiíier Engine Systems Engine Adaptation Reterences Reíerences and Making Operation 137 133 Decision 127 124 Handbook of Biomass Downdraft Gasitier Engine Systems Saíety and Environmental Considerations 119 Appendix: Units and Conversions 139 n = + + + l4fU + * U.S GPO: 1988 573-098/80,000 [...]... and labor Biomass 16 MBtu/ton $32/ton Reliance Source: Gengas 1950 138 Handbook of Biomass Downdraft Gasiỉier Engine Systems Satety and Environmental Considerations 121 Reíerences 131 120 of Downdraft Gasiíier Engine Systems Decision Making 125 126 Handbook of Biomass Downdraft Gasitier Engine Systems 136 HandbooK ofBiomass Biomass Downdraft Gasifier Engine Systems 132 Handbook of Biomass Downdraft. .. has been Engine Adaptation Adaptation and and Operation Operation 107 109 106 Handbook of Biomass Downdraft Gasitier Engine Systems Engine 102 104 Handbook Handbook of of Biomass Biomass Downdraft Downdraft Gasitier Gasitier Engine Engine Systems Systems Instrumentation and Control 103 108 Handbook of Biomass Downdraft Gasitier Engine Systems Engine Adaptatíon and Operatíon 105 The power lost awhen... primary Fig 8-2 Scrubber pedormance and sharpness comparison (Source: See reíerence in Table 8-1) 72 Handbook of = 8 = 95 a b c d 3 78 80 of Downdraft Gasiỉier 76 74 Handbook Handbook of Biomass Biomass Downdraft Gasifier Engine Engine Systems Systems Biomass Downdraft Gasitier Engine Gasitier Systems 79 Gas Gas Cleaning 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