TECHNO-ECONOMIC ANALYSIS OF A MODEL BIOGAS PLANT FOR AGRICULTURAL APPLICATIONS; A CASE STUDY OF THE CONCORDIA FARMS LIMITED, NONWA, TAI, RIVERS STATE

TECHNO-ECONOMIC ANALYSIS OF A MODEL BIOGAS PLANT FOR AGRICULTURAL APPLICATIONS; A CASE STUDY OF THE CONCORDIA FARMS LIMITED, NONWA, TAI, RIVERS STATE BY TORBIRA MTAMABARI SIMEON (PG/M.ENG/06/41561) DEPARTMENT OF MECHANICAL ENGINEERING UNIVERSITY OF NIGERIA, NSUKKA NOVEMBER 2009 TECHNO-ECONOMIC ANALYSIS OF A MODEL BIOGAS PLANT FOR AGRICULTURAL APPLICATIONS; A CASE STUDY OF THE CONCORDIA FARMS LIMITED, NONWA, TAI, RIVERS STATE BY TORBIRA, MTAMABARI SIMEON PG/M.ENG/06/41561 OPTION: INDUSTRIAL ENGINEERING AND MANAGEMENT A PROJECT REPORT SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE AWARD OF THE DEGREE OF MASTER OF ENGINEERING (M.ENG) IN MECHANICAL ENGINEERING UNIVERSITY OF NIGERA, NSUKKA, NIGERIA NOVEMBER 2009 i TITLE PAGE “TECHNO-ECONOMIC ANALYSIS OF A MODEL BIOGAS PLANT FOR AGRICULTURAL APPLICATIONS; A CASE STUDY OF THE CONCORDIA FARMS LIMITED, NONWA, TAI, RIVERS STATE” ii CERTIFICATION This is to certify that TORBIRA, MTAMABARI S., a postgraduate student in the Department of Mechanical Engineering with registration number PG/M.Eng/06/41561 has satisfactorily completed the requirements for the course work and research for the award of Master’s degree in Mechanical Engineering (Industrial Engineering and Management) The work is original and has not been submitted either in part or full for the award of certificate of any other Institution or University ……………………………………… TORBIRA, Mtamabari Simeon (Student) ……………………………………… Engr Professor S.O Enibe (Supervisor) ……………………………………… Engr Professor S.O Onyegegbu (Head of Department) ……………………………………… External Examiner iii DEDICATION This work is dedicated to the educationally less privileged ones in the society especially those who have the academic potentials and vision but could not realize it iv ACKNOWLEDGEMENTS I would like to thank some of the people that have helped and supported me in accomplishing this study A special thanks goes to my supervisor, Engr Prof S.O Enibe for his critical but constructive comments, advice, inspiration, support and mentoring Also worthy of thanks is the Head, Department of Mechanical Engineering, Prof S.O Onyegegbu Thanks also to Njoku Howard who made meaningful contributions to an earlier version of this project report My gratitude also extends to the Manager, Mr Beema N and the entire management of Concordia Farms for giving me the permission to use their reputed farm as a case study for this research I am very grateful to my father, Mr Lenee T Nwiakoro, and Dr E.N Nwosu who gave me the needed financial and moral support to accomplish this work I appreciate also, the effort of Ogbonna, Eucharia I who took his time to type this work The Almighty God; His goodness, mercies, loving kindness and grace for me, is kindly acknowledged v TABLE OF CONTENTS Title Page - - - - - - - - - - i Certification - - - - - - - - - - ii Dedication - - - - - - - - - - iii Acknowledgement - - - - - - - - - iv Table of Contents - - - - - - - - v List of Tables - - - - - - - - - viii List of Figures - - - - - - - - - x Abstract - - - - - - - - - xiv CHAPTER ONE: INTRODUCTION - - - - - 1.1 - - - - - 1.1.1 Primary and secondary energy sources - - - - 1.1.2 Available non-renewable energy sources - - - - 1.1.3 Non-renewable energy and their advantages - - - 1.1.4 Non-renewable energy and their liabilities - - - - 1.2 - - - - - - Non-renewable energy sources Renewable energy resources - 1.2.1 Solar energy - - - - - - - - 1.2.2 Wind energy - - - - - - - - 1.2.3 Geothermal energy - - - - - - - 10 1.2.4 Hydropower - - - - - - - - - 10 1.2.5 Ocean energy - - - - - - - - 11 1.2.6 Wave energy - - - - - - - - 11 1.2.6.1 Tidal energy - - - - - - - - 11 1.2.6.2 Ocean thermal energy conversion - - - - - 12 1.2.7 Hydrogen energy - - - - - - - - 12 1.2.8 Biomass energy - - - - - - - - 13 1.2.9 Bio-fuels - - - - - - - - 19 1.2.9.1 Current Bio-fuels used as energy sources - - - - 20 1.3 - - - 23 Biogas - - - - - - - vi 1.3.1 Mechanisms of biogas production - - 25 1.3.2 Environmental requirements for anaerobic digestion - - - 28 1.4 Biogas plants in integrated farms - - - - - - - - 29 1.4.1 Biogas Application in integrated farms - - - - - 29 1.5 Solar heating biogas plant - - - - - - 35 1.6 Environmental impact - - - - - - - 36 1.7 Methodology - - - - - - - - 37 1.8 Update of Biogas technology in some countries- - - - 38 CHAPTER TWO: DESCRIPTION OF THE CASE STUDY FARM - - 40 2.1 - Description of the case study farms - - - - - 40 2.1.1 Accommodation/Offices - - - - - - - 40 2.1.2 Growth level of farms - - - - - - 40 2.1.3 Farm implements and facilities - - - - - - 41 2.1.4 Farm power - - - - - - 41 - - - - 43 - - - - 43 - - - 43 3.1.2 Analysis of organic waste generation of the farm - - - 45 3.1.3 Design of the proposed biogas plant - - - 47 3.1.4 Volume calculation of the digester and hydraulic Chamber - 56 3.1.5 - - - CHAPTER THREE: ANALYSIS OF A BIOGAS PLANT FOR THE CASE STUDY FARM - 3.1 Technical Analysis of the Biogas plant - 3.1.1 Analysis of the energy requirement of the Farm Thermal analysis - - - - - - - 59 3.1.6 Analysis of biogas generation prospects of the 3.2 Farm with its energy requirements - - - - - 62 Economic Feasibility - - - - - - - - 63 - - - - - - - - 63 3.2.2 Financial analysis - - - - - - - - 63 3.2.3 Project life - - - - - - - - - 64 3.2.4 Benefits and cost - - - - - - - - 65 3.2.1 Introduction - vii 3.2.5 Cash flow Analysis - - - - - - - 69 3.2.6 Time Value of Money and Discount Rate - - - - 70 3.2.7 Net present value (N P V) - - 70 - 71 - - - - 3.2.8 Internal Rate of Returns (I R R)- - - - 3.2.9 Benefit-Cost ratio - - - - - - - - 72 3.3 - - - - - - - 75 3.3.1 Economic valuation of firewood- - - - - 76 Economic Analysis 3.3.2 Economic valuation of Kerosene, PMS, and Diesel - - 76 3.3.3 Economic valuation of labor - - - - - - 76 3.3.4 Valuation of slurry - - - - - - - 77 3.3.5 Investment cost - - - - - - - 77 CHAPTER FOUR: RESULTS AND DISCUSSION - - - - 78 4.1 Parameters and Values used in the Analysis - - - 78 4.2 Energy Audit of the Farm - - - - 80 4.3 Volume calculation of digester and hydraulic chambers - - 81 - - - - 4.3.1 Volume of digester- - - - - - - 81 4.3.2 Hydraulic chamber - - - - - - - 81 4.3.3 Area and Dimension of digester - - - - - 81 - - 83 - - 85 - 86 4.3.4 Variation of volume of biogas with percentage total solid Concentration - - - - - - 4.3.5 Variation of digester volume with substrate at HRT of 40 days - - - - - - - 4.3.6 Variation of digester volume with HRT at substrate value of 13,625kg 4.4 - - - - - - - - Comparison of biogas generation prospects of the Farm with its Energy requirements - - - - - - - 88 4.5 Thermal Analysis - - - - - - - - 89 4.6 Financial Analysis - - - - - - - - 89 4.7 Cost distribution of 681.3 m3 biogas plant - - - - 91 CHAPTER FIVE: CONCLUSION - - - - - - 93 REFERENCES - - - - - - - 96 - - viii LIST OF TABLES Table 1.1: Summary of estimated non-renewable energy Reserves in Nigeria - - - - - - - Table 1.2: Summary of estimated non renewable energy reserves in the World - - - - - - - - - - - - 17 Table1.3: Available renewable energy resources in the World and Nigeria - - - - Table 1.4: Installed electricity generation plant in Nigeria and available capacities - - - - - - - 19 Table 1.5: Countries with Biogas producing units - - - - 39 Table 2.1: Farm implements and facilities - - - - 41 - - - - 42 Table 2.3: Types and number of livestock reared on the farm - - 42 Table 3.1: Heating value of some fuels - - - - - 43 Table 3.2: Energy audit of farm - - - - - - 45 - 46 - 50 - - 51 - Table 2.2: Monthly fuel consumption of the farm - Table 3.3: Discharge per day, Total solid value of fresh discharge and Water to be added to make favorable T.S condition Table 3.4: List of building materials and their costs for a 681 25cm3 active biogas plant for the case study farms - - Table 3.5 Discharge per day, Total solid value of fresh discharge and Water to be added to make favorable TS condition Table 4.1 Parameters and values used in analysis - - - - 78 Table 4.2: Results of energy of the farm - - - - - 81 Table 4.3: Areas and Dimensions of digester - - - - 82 - - 84 - - 85 - 87 Table 4.4: Relationship between percentage total solid Concentration and volume of biogas generated - - - Table 4.5 Variation of digester volume with substrate at HRT of 40 days - - - - - - - Table 4.6 Variation of digester volume with HRT at substrate value of 13,625kg - - - - - - - 97 18 March 2004 How Stuff Works, “How a Fuel Cell Works”, (www.howstuffworks.com/fuelcell.html).Retrieved on the 4/7/2007 Hubbert M.K [1985], “Techniques of prediction as applied to the production of oil and gas” In, S.I Gas (ed), Oil and Gas supply modeling, special publication 631, National Bureau of standards, Washington DC, p.16141 Igoni A.H, Abowei M.F.N, Ayotamuno, M.J and Eze C.L “Effect of Total Solids Concentration of Municipal Solid Waste on the Biogas produced in an Anaerobic Continuous Digester” Agricultural Engineering International: the CIGR EJournal Manuscript EE 07 010 Vol X P8 September, 2008 Iloele, O.C Power Plant Engineering, Lecture handbook, 2004 Intermediate Technology Development Group (ITDG), “Wind for Electricity Generation” (http://www.windpower.dk) Retrieved on the 4/7/2007 Jackson T., Stockholm Stovkholm, Environmental Institute (SEI) 177-184 Jo Lawbuary, “Install a Biogas Plant to eliminate drudgery of women” www.biogastechnologyinindia Retrieved on the 4/30/2007 Khadi and Village Industries Commission (KVIC), “Cost-Benefit Analyses of biogas production” (http://www.unu.edu/unupress/unupbooks/80434e/80434E0K.htm), Retrieved 4/30/2007 Licht, F.O.(2003), World Ethanol and Biofuel Report vol.1, No.19, 12 June 2003 M.M El-Halwagi London, Elsevier Applied Science Publishers: 661-664 Local Government Engineering Department (LGED), “Bio-gas project-LGED” (Available online) @ http://www.lgedrein.org/archive_filepublications_Design%20Biogas%20plant.pdf, Retrieved 4/30/2007 Mattock R (1984), “Understanding Biogas Generation”, Volunteers in Technical Assistance Available online @ http://www.pr-info@vita.org, Retrieved 5/15/2008 Monle Nagbi, Farm Chief Agriculturist, Interviwed on the 17th – 18th May 2007 98 Osakwe, E.N.C (2008),’’Biogas Plant Construction Project’’, A Proposal, Pope John Paul II Major Seminary, Awka,2008 Polprasert, Chongrak, “Organic waste recycling technology and management”, (1996) John Wiley and sons Ltd, Baffins Lane, Chichester west Sussex PO19 IUD, England Price, E.C., and Cheremisinoff, P.N (1981) Biogas Production and Utilization Ann Arbor Science, Ann Arbor Rady, H.M (1993), Renewable Energy in Rural Areas of Developing Countries Rubab, S and Kandpal T.C (1996) A Methodology for Financial Evaluation of Biogas Technology in India Using Cost Functions, in Biomass & Energy, Editors: J Coombs, D.O.Hall, R.P.Hall and W.H Smith, Vol.10, No1., ISSN 0961-9534 Elsevier Science Ltd, United Kingdom Rural Energy – Medium and large-scale biogas systems in the Asia-pacific Region (1995) ISSN 1011 – 6443 RAP Bulletin, 10th Anniversary RAPA, Bangkok, Thailand Rutamu Innocent, “Low cost biodigesters for zero grazing small-holder daily farmers in Tanzania”, Livestock research for Rural Development (II) 2, 1999 Singh et al (1995), Effect of Biogas Digested Slurry on Pea, Okra, Soybean and Maize Biogas forum Volume FV, N0 63 pp 4-7 Singh K.K, Thermal Analysis of Solar-assisted Biogas Community Plant Ph.D Thesis, L.N Mithilia University, Daibhanga India (1989) Tam, D.M and Thanh, N.C (1981) Biogas Technology in Developing Countries: An Overview of perspectives ENSIC Review 109 Environmental Sanitation Information Center, Asian Institute of Technology, Bangkok Technology of Biogas Production and Applications in Rural Area (1989) Report by World Energy Conference, London United Kingdom Tiwari G.N, Singh S.K, and Tharkur Kailash, [1999], “Design criteria for an active biogas plant”, Energy vol 17, No.10, pp.955-958, 1992 Tiwari G.N.,“Fundamentals, Design, Modeling and Applications, Solar Energy” (2006), Norosa publishing house, New Delhi Chennai Mumbai Kolkata – India 99 USMANI J.A.,TIWARI G.N., CHANDRA A [1995], Performance “characteristic of a greenhouse integrated biogas system”, Energy Conservation and management Center for energy studies, Indian Institute of Technology, Delhi India ViJay V.K, Prasad R.,Singh J.P and Sorayan V.P.S, [2000], “A case for Biogas energy application for rural industries in India” Center for Rural Development, IIT, New Delhi, India Williams P.T., (2005), “Waste treatment and disposal”, John Willey (Eds), Great Britain Wire Magazine, (2003) “How Hydrogen Power Can Save America” (www.wired.com/wired/archive/11.04/hydrogen.html) Retrieved on the 4/30/2009 Young J.C and McCarthy P.L, (1969) “Journal of Water Pollution Control Federation 41 (5), 160 100 APPENDIX-A VERBAL INTERVIEW (DRAFTED COPY) DATE: 14TH-18TH MAY 2007 Here is a copy of the verbal questionnaire that was used to extract relevant information about Concordia farms limited for the purpose of this research work (1) Please could you tell me a brief history of your farm? (2) How is the organizational pattern of Concordia farms? (3) How would you assess the growth level of the farm since its inception? (4) What is the size of your farm (in terms of land area)? (5) What types(s) of farming is being practice by Concordia farms? (6) Please give me a detail of the type and number of live stock/bird/fish reared on your farm? (7) What types of crop does your farm cultivate? (8) What does your farm uses the huge organic waste generated for? (9) Which is/are your source(s) of energy to the farm? (10) What quantity of fuels does your farm consume per mouth? (11) How much (cost in Naira or Dollar), does your farm spent on each types of fuel, say, in one month? (12) What farming operations your farm uses these fuels for? 101 (13) Please mention the farm equipments/implements and facilities available on your farm, stating their capacities, quantities and ratings? (14) What are the sources of farm power available to Concordia Farms? (15) Does Concordia farms uses electricity supplied from external source? (16) Does your farm buy chemical fertilizers for manure? (17) Have your farm built/own a biogas plant (past or present)? 102 APPENDIX- B Relevant Data on Biogas TABLE-B 1: THE TOTAL SOLID CONTENT OF COMMON FERMENTATION MATERIALS IN RURAL AREAS (APROXIMATELY) Materials Dry rice straw Dry wheat straw Corn stalks Green grass Human excrement Pigs excrement Cattle excrement Human urine Cattle urine Dry matter content (%) 83 82 80 24 20 18 17 0.4 0.4 0.6 Water content (%) 17 18 20 76 80 82 83 99.6 99.6 99.4 Source: Bio-gas project, LGED (2007) 103 TABLE-B2: BIOGAS-PRODUCING RATES OF SOME COMMON FERMENTATION MATERIALS AT DIFFERENT TEMPERATURES (M3/Kg TS) Materials Pig manure Cattle dung Human wastes Rice straw Wheat straw Green grass Medium temperature (35oC) 0.45 0.30 0.43 0.40 0.45 0/44 Water content (8o  25oC) 0.25 – 0.30 0.20 – 0.25 0.25 – 0.30 0.20 – 0.25 0.20 – 0.25 0.20 – 0.25 Experimental conditions: - The fermentation period of the excrement materials lasts 60 days and that of the stalk type lasts 90 days The fermentation material concentration (total solid content) is 6% Source: Bio-gas project, LGED (2007) 104 TABLE –B 3: BIOGAS PRODUCING RATES OF SOME FERMENTATION MATERIALS AND THEIR MAIN CHEMICAL COMPONENTS Materials and their Yield of Biogas m3/kg main components TS Animal barnyard manure Pig manure Horse droppings Green grass Flax straw Wheat straw Leaves Sludge Brewery liquid waste Carbohydrate Liquid Protein 0.260 – 0.280 0.561 0.200 – 0.300 0.630 0.359 0.432 0.210 – 0.294 0.640 0.300 – 0.600 0.750 1.440 0.980 Methane content (%) Source: Bio-gas project, LGED (2007) 50 – 60 70 59 58 50 58 49 72 50 105 TABLE -B 4: BIOGAS – PRODUCING RATES OF SEVERAL SUBSTANCES Material YpCMDV (m3/ m3d) YpKgM (m3/kg TS) Water 0.40 0.16 Amount of biogas produced in a period of time (as a % of the total yield) – 15(d) 83 hyacinth Alligator weed Water lettuce Cattle dung Pig manure Human waste Dry grass 0.38 0.40 0.20 0.30 0.53 0.20 0.20 0.20 0.12 0.22 0.31 0.21 23 23 11 19.6 45 13 15-45(d) 45-75(d) 75-13(d) 17 0 45 62 33.8 31.8 22 11 32 15 20.9 25.5 27.3 43 0 34.3 23.1 5.7 33 Note: - The fermenting temperature is 30oC It is batch-fed fermentation YpCMDV refers to the average yield of biogas per cubic meter of the digester volume during the period of normal fermentation (m3/kg TS) Source: Bio-gas project, LGED (2007) 106 TABLE – B 5: THE SPEED OF BIOGAS PRODUCTION WITH COMMON FERMENTATION MATERIALS Speed Amount of biogas produced in a period Biogas of time (expressed as a percentage of producing the total yield of biogas) 10 20 30 40 50 60 70 80 90 Time (d) Materials Human wastes rate (m3/kg TS) 40.7 81.5 94.1 98.2 98.7 100 0.478 Pig manure * * ** 46.0 78.1 93.9 97.5 99.1 100 0.405 Green grass - Cattle dung Wheat straw ** 34.4 74.6 86.2 92.7 97.3 100 8.8 30.8 53.7 78.3 88.7 93.2 96.7 98.9 * * - 100 * ** - 98.2 - 100 ** 0.410 0.300 0.435 ** * Biogas producing is at the highest speed ** Amount of biogas produced to more than 90% of the total yield of a fermentation period Experimental conditions: - Fermenting temperature 35oC, the total length of fermentation period being 60 days for the excrement material and 90 days for the stalk type, the materials concentration, total content of the fermentative fluid being 6% Source: Bio-gas project, LGED (2007) 107 TABLE –B 6: CARBON-NITROGEN RATIOS OF SOME COMMON FERMENTATION MATERIALS (APPROX.) Material Carbon content of Nitrogen content Carbon-nitrogen material (%) 46 42 40 41 41 14 11 of materials (%) 0.53 0.53 0.75 1.00 1.30 0.54 0.59 ratio (C/N) 87:1 67:1 53:1 41:1 32:1 27:1 19:1 leaves Fresh sheep 16 0.55 29:1 droppings Fresh cattle dung Fresh horse 7.3 10 0.29 0.42 25:1 24:1 droppings Fresh pig manure Fresh human 7.8 2.5 0.60 0.85 13:1 29:1 Dry wheat straw Dry rice straw Corn stalks Fallen leaves Soy bean stalks Wild grass Peanut stems and wastes Source: Bio-gas project, LGED (2007) 108 TABLE-B 7: AMOUNT OF HUMAN AND ANIMAL WASTES DISCHARGED PER DAY (APPROX.) Kinds Pig Body weight (kg) Daily amount of urine (kg) Daily amount of excrement discharge (kg) Annual amount of excrement discharged (kg) Annual amount of excrement collected (kg) Daily yield of biogas per capita (m3) 50 15 2190 1752 0.18 – 0.25 34 34 12410 9928 0.36 – 0,96 Ox Horse 500 10 15 3650 2920 Sheep 500 1.5 548 438.4 Chicken 15 0.10 36.80 29.44 0.0076 – 0.0112 Human 50 0.50 182.50 146.00 0.028 Note:- The annual amounts of excrement collected accounts for 80% of that discharge Source: Bio-gas project, LGED (2007) 109 APPENDIX-C COMPUTER PROGRAMME The Equation software, Engineering Equation Solver (EES), has been used for calculating the thermal efficiency, energy audit, volume & area of digester Also calculated were hydraulic chamber dimensions, biogas yield analysis, financial/cost analysis and parametric analysis of the biogas plant These were run to give results EES can solve many types of equations It can run under 32-bit Microsoft Windows operating systems i.e., Windows 95/98/2000/XP.It can be run in the Linux and on the Macintosh using emulation programmes Below is the programme Knowns” Q_yf=20000;P_f=6.40;Q_yk=4725;P_k=70.00;Q_yc=3500;P_c=2.50;Q_yd=8350;P_d=65 00;Q_yp=7350;P_p=70.00;H_f=12.00;H_k=46.25;H_c=9.00;H_d=46.00;H_p=46.80 Calculate” C_f= Q_yf*P_f C_k = Q_yk*P_k C_c = Q_yc*P_c C_d =Q_yd*P_d C_p= Q_yp*P_p E_f =Q_yf*H_f E_k = Q_yk*H_k E_c = Q_yc *H_c E_d = Q_yd *H_d E_p = Q_yp *H_p U_cf = C_f / E_f U_cc = C_c / E_c U_cd = C_d / E_d U_cp = C_p / E_p U_ck = C_k / E_k E_total = E_f + E_k + E_c + E_d+ E_p “Total energy utilized on farm” C_total =C_f+C_k+C_c+C_d +C_p “Total Cost of energy” Knowns” N_c=300;TS_vcd=0.16;C_dc=10 C_dtc=C_dc*N_c TS_c=C_dtc*TS_vcd q_c=(100*C_dc*N_c* TS_vcd )/8 L_dc=(100*C_dc*N_c* TS_vcd /8)-( C_dc*N_c ) Knowns” N_p=400;C_dp=6;TS_vpd=0.20 C_dtp= C_dp*N_p TS_p=C_dtp *TS_vpd q_p=(100*C_dp*N_p*TS_vpd )/8 L_dp=(100*C_dp* N_p*TS_vpd /8)-( C_dp*N_p) Knowns” N_b=3500;TS_vbd=0.20;C_db=0.10 “Influent from cattle” “Influent from pig” 110 C_dtb=C_db*N_b TS_b=C_dtb*TS_vbd q_b=(100*C_db*N_b*TS_vbd)/8 L_db= (100*C_db*N_b*TS_vbd /8)-( C_db*N_b ) Knowns” N_s=200;TS_vsd=0.20;C_ds=1.5 C_dts=C_ds*N_s TS_s= C_dts *TS_vsd q_s = (100*C_ds*N_s*TS_vsd)/8 L_ds= (100*C_ds*N_s*TS_vsd /8)-( C_ds*N_s) Q=q_c+q_b+q_s+q_p L_dt=L_ds+L_dp+L_dc+L_db TS” “Influent from poultry” “Influent from sheep” “Total Influent from livestock” “Total water to be added to make 8% Knowns” HRT=40;M_gsc=0.28;M_gsp=0.561;M_gsb=0.28;M_gss=0.28;a=1000;p=3.14;h_n=8.0; 0.80*V=Q*HRT/a “calculate digester volume” D= 1.3078*V^0.333 V_3= 0.3142*D^3 H= 4*0.3142*D/3.14 “digester height” F_1=D/5 F_2=D/8 R_1=0.725*D R_2=1.0625*D V_1=0.0827*D^3 R= D/2 “radius of digester” V_c=0.05*V V_gs=0.5*(TS_c*M_gsc)+(TS_p*M_gsp)+(TS_b*M_gsb)+(TS_s*M_gss) V_1=(V_gs+V_c)-(p*D^2*H_1)/4 h_n=h_3+F_1+H_1 V_gs=p*D_h^2*h_3/4 F_t=p*(R)^2+(F_1)^2 F_c=2*p*R*H F_b=p*(R^2+(F_2)^2) F = F_t+F_c +F_b “Total area of digester” Knowns” Y_c=0.36;Y_s =0.10;Y_p=0.25;Y_b=0.0112;H_b=20 Y_tc=Y_c*C_dtc;Y_ts=Y_s*C_dts;Y_tp=Y_p*C_dtp;Y_tb=Y_b*C_dtb Y_T=(Y_tc+ Y_ts + Y_tp + Y_tb) “Total biogas yield/day” E_b=H_b*Y_T “energy per day from biogas” Knowns” P_wages=300;R_r=18314175;D_d=100000;i=0.2;N=20;P_I=5954100;y=3.09 P_R = R_r*((1+i)^N-(1))/(i*(1+i)^N), P_Db= D_d*((1+i)^N-(1))/(i*(1+i)^N) P_T=(P_I+P_Db) NPV=(P_R)-( P_I+P_Db) -P_I+(R_r-D_d)*((1+e)^N-(1))/(e*(1+e)^N)=0 NI=P_R EX=(P_I+P_Db) B_c= P_R /(P_I+P_Db) Y_wages = (y*365/8)*P_wages “Net Present Value” “Benefit-Cost Ratio” "Cost of labour saved” Knowns” P_ce=696000;P_sch=1522500;P_rww=2573200; P_acc=7000;P_tran=100000;P_pfn=112000;P_lab=692000;P_ov=100000;P_solp=45140 0;P_to=6254100 111 q_ce= (P_ce*100)/P_to q_sch =(P_sch*100) /P_to q_rww= (P_rww*100)/P_to q_acc= (P_acc*100)/P_to q_tran=(P_tran*100)/P_to q_pfn=(P_pfn*100)/P_to q_lab=(P_lab*100)/ P_to q_ov=(P_ov*100)/ P_to q_solp= (P_solp*100)/ P_to knowns” A_c=8;A_h=165.7; A_t=384.5;A_to=108.8 C_f=4190;C_s=4180;h=20.00;h_1 =19.23;h_b=3.194;I=400;L =19.83;M_s=13625;m_f=4.0;N=4 T_a=28;t=17337;U_o=17.08;U_L=13.4;F^1=0.81;T_fi=40;T_fo=50;T_so=29;T_s=38;at= 0.8;T_f=44 Q_u=h*L*(T_f-T_s) Ft=m_f*C_f*(1-exp(-B))*(1-exp(-K))/(1-exp(-K-B)) K=(N*A_c*U_L*F^1)/(M_f*C_f) B=h*L/ (m_f*C_f) Z=A_t+A_to a=(Ft+1/((1/U_o*1/A_to)+(1/h_1*1/A_h))+h_b*Z)/(m_s*C_s) E_f=((1-exp(-a*t))/(a*t*N*A_c))*((Ft*a*t/U_L)-a*m_s*C_s*(T_so-T_a)/I) “Thermal efficiency” V_d=q*HRT/800;Vtc=0.2225*PTS^ 2.7717 ...2 TECHNO-ECONOMIC ANALYSIS OF A MODEL BIOGAS PLANT FOR AGRICULTURAL APPLICATIONS; A CASE STUDY OF THE CONCORDIA FARMS LIMITED, NONWA, TAI, RIVERS STATE BY TORBIRA, MTAMABARI SIMEON PG/M.ENG/06/41561... UNIVERSITY OF NIGERA, NSUKKA, NIGERIA NOVEMBER 2009 i TITLE PAGE ? ?TECHNO-ECONOMIC ANALYSIS OF A MODEL BIOGAS PLANT FOR AGRICULTURAL APPLICATIONS; A CASE STUDY OF THE CONCORDIA FARMS LIMITED, NONWA, TAI,. .. calculation of the digester and hydraulic Chamber - 56 3.1.5 - - - CHAPTER THREE: ANALYSIS OF A BIOGAS PLANT FOR THE CASE STUDY FARM - 3.1 Technical Analysis of the Biogas plant - 3.1.1 Analysis of the