Study the substitution of fossil fuels by RDF produced from municipal solid waste of hanoi m a thesis waste management and contaminated site treatment

VNU UNIVERSITY OF SCIENCE TECHNISCHE UNIVERSITÄT DRESDEN N g u y en Bich Ngoc S T U D Y T H E S U B S T I T U T I O N O F F O S SIL F U E L S BY R D F P R O D U C E D F R O M M U N I C IP A L S O L ID W A S T E O F H A N O I Major: W aste M a n a g e m e n t and C ontam inated Site T reatm ent C ode M A S T E R T H E S IS S U P E R V IS O R : PR O F DR N G U Y E N THI D IE M T R A N G ĐAI HỌC QUỐC GIA HÀ NƠI TRUNG TAM THĨNG TIN THƯ VIÊN H anoi - 2011 ACKNOWLEDGEMENT I own my deepest Thi Diem Trang believing, great gratitude to my supervisor Without I could her patiently not complete opportunities for this learning Prof support thesis new Nguyen She things and gave me as well as training myself I would like Bilitewski, National to express Technische University Service (DAAD) for my thankfulness Universität and The German organizing this to Prof Dresden, Vietnam Academic Exchange Master course It is also an honor for me to study with devoted professors and lecturers the within this course They knowledge but also a new vision, It is a pleasure possible Ms to thank only gave me a new way of thinking those who made this thesis Dang Ngoc Chau and my three friends Hop, Chuong I am also grateful for Ms of valuable her not comments and Tao, Tran Thi Nguyet because support during my thesis wri ting I would like to thank my many of my colleagues for their encouragement during this course and for the time we spent together The special thank goes to my parent and my I would like to show my gratitude to little sister for their love and endless support Last my but not least, amant Thank you for always standing helping me overcome difficult time by my side and 2.3.1 CO emission calculation 36 2.3.2 Nitrous oxide em ission 37 R e s u l t s a n d d i s c u s s i o n 38 3.1 RDF preparing process tro l 38 3.1.1 Stabilization tim e 38 3.1.2 Tem perature 39 3.1.3 Leachate volume 41 3.1.4 Water co n ten t 42 3.2 RDF q u ality 44 3.2.1 R D F com position 44 3.2.2 Heating va lu e 45 3.3 GHGs estimation 47 3.3.1 Pre-treatment ste p 3.3.2 RDF utilization ste p 48 3.3.3 Total GHGs em ission 49 C o n c l u s i o n 51 R e f e r e n c e s .5 M aster Thesis L ist o f figures/ tobies L ist o f f ig u r e s Figure 1: Global energy consumption from 1985 to 2010 (million tons o f oil equivalent) [1 ] Figure 2: Rotterdam product oil prices - US dollarsper barrel [ ] 10 Figure 3: Natural gas price (dollars/Btu) [ ] .11 Figure 4: Shares o f world primary energy [ 1] 12 Figure 5: Electricity consumption in Vietnam (kWh per cap ita ) 13 Figure : Share o f total primary energy supply in Vietnam in 200 14 Figure 7: Waste composition o f Hanoi [2 ] 15 Figure 8: Densified RDF (Saitama Prefectural Environmental Management Center, Ja p a n ) 20 Figure 9: Schematic Representation o f MBT Process [8 | 23 Figure 10: Herhof Stabilat method [11] 25 Figure 11: Schematic diagram o f MBT CD.08 [14] 28 Figure 12: Heat value o f RDF product - MBT CD.08method [ 14] 29 Figure 13: RDF composition for barrels 31 Figure 14: RDF sample preparing process 32 Figure 15: Waste barrel 33 Figure 16: Temperature in stabilization barrels 39 Figure 17: Composting temperature depending on C:N r a tio 40 Figure 18: Temperature differences in stabilization barrels 41 Figure 19: Leachate v o lu m e 42 Figure 20: Water co n te n t 43 Figure 21: Waste input composition (left) and estimated RDF output composition (right) - (a) sample 1, (b) sample 2, (c) sample 45 Figure 22: Gross heating value comparison with fossil fuel and RDF from different studies 47 Figure 23: GHGs emission from RDF sample compare with fossil fuel (kg C 2.Cq ,'MJ) [ ] .50 L ist o f figures/ tables M aster Thesis L i s t OF TABLES Table 1: Waste composition in Hanoi in 1995 and 2003 [20] 15 Table 2: MSW eeneration and collection rate in cities/towns in Vietnam 16 Table 3: Type o f refuse derived fuel 18 Fable 4: Typical RDF composition in some resions [8] 20 Table 5: Quality o f RDF from household and industrial sources [8] .21 Table : Quality o f RDF in some Europe Countries [17] 22 Table 7: Conversion rate for RDF production according to treatment process and country 26 Table 8: Annual RDF production from MSW in some countries [1] 27 Table 9: Waste input characteristics for RDF production (Đặng Ngọc Châu experiment) [6] 29 Table 10: Comparison RDF product quality [6, 14] 30 Table 11: Waste input com position .32 Table 12: Characteristics o f waste fraction (Vietnam based) [9 ] 35 Table 13: GW P according to IPCC [18] 36 Table 14: Stabilization tim e 38 Table 15: Reduction o f waste fraction after composting [1 6] 44 Tabic 16: Heating value 46 Table 17: C emission from combustion process (kg/kg R D F) 48 M a ster Thesis Introduction In t r o d u c t i o n Vietnam is one o f the most rapidly developing countries in last decades High density o f population and quickly growing o f living standard as well as consumerism give Vietnam more and more challenges One o f them is the growth o f energy demand in all sectors Prices of electricity and gasoline - two main energy sources in Vietnam - are constantly increasing in recent years Clean and renewable energy has become an interesting topic which draws much attention from the society as well as the scientific community Another side-effect o f development which is also brought by consumerism and high population is rapid increase o f solid waste generation However, an efficient solution for solid waste management especially municipal solid waste management is still a challenge in Vietnam One reason is that waste management in Vietnam lacks separation at source To cope with those problems, energy from waste is being studied and considered a solution There are several ways for converting waste into energy which have different requirement on technology and finance One o f them is RDF production by bio-stabilization method which is considered as a suitable way when investment is limited and there is not waste separation at source There are several researches on this topic in Vietnam which showed possibility o f implementation bio-stabilization as RDF production method in Vietnam Based on previous study, this research “Study the substitution of fossil fuels by RDF produced from municipal solid waste of Hanoi” was carried out with the following objectives: • Assessment of bio-stabilization process in RDF producing • Study the influence o f waste composition on RDF quality • Evaluation of Green House Gases (GHG) emission and other RDF quality parameter to assess the possibility o f substitution RDF for fossil fuel M aster Thesis Theoretical background T h e o r e t i c a l b a c k g r o u n d 1.1 Situation o f global energy consu m ption / / Global energy consumption In history, the world energy consumption is constantly increasing except some periods when it slightly reduced mainly due to economic problem In 2010, global energy consumption rebounded strongly, driven by economic recovery The growth in energy consumption was broad-based, with mature OECD economies joining non-OECD countries in growing at above-average rates All forms o f energy has grown strongly, with growth in fossil fuels in 2010 suggesting that global C emissions from energy use grew at the fastest rate since 1969 [1] W orld c o n su m p tio n Minor, tcmntt o» 130£K Cod RanawaMe* 1200C ■ Hytfroeiectriaty * f'iuctov energy ■ 1100C N a tu ral g a s ■ Ol 10003 900C 7000 eox 5000 aooc Figure 1: Global energy consumption from 1985 to 2010 (million tons of oil equivalent) [1] Figure shows the trend o f energy consumption in the world After falling for two consecutive years, global oil consumption grew by 2.7 million barrels per day (b/d), or 3.1%, to reach a record level o f 87.4 million b/d This was the largest percentage increase since 2004 but still the weakest global growth rate among fossil fuels World natural gas consumption grew by 7.4% - the most M aster Thesis Theoretical background rapid increase since 1984 On the other hand, coal consumption also grew by 7.6% in 2010 Coal now accounts for 29.6% o f global energy consumption, up from 25.6% 10 years ago Energy price developments were mixed Oil prices remained in the $70-80 range for much o f the year before rising in the fourth quarter With the OPEC production cuts implemented in 2008/09 still in place, average oil prices for the year as a whole were the second-highest on record (Figure 2) [1] H Gasoline ■ Gas oil ■ Heavy fu el Oil 160 150 140 130 120 ñ j 110 100 i J r k M r J * / H 93 94 9S / J V v J Ar 96 97 ,y k - s -s s 00 ot J\ J1 J / A ft / 90 J / J 70 w V 1 60 50 40 / / k - 80 30 20 10 02 03 04 os 06 07 OB 09 10 Figure 2: Rotterdam product oil prices - u s dollars per barrel [1] According to 2011 Beyond Petroleum (BP) report, natural gas prices in 2010 grew strongly in the UK and in markets indexed to oil prices (including much o f the world’s LNG); but prices remained weak in North America - where shale gas production continued to increase - and in continental Europe (partly due to a growing share o f spot-priced deliveries) (see Figure 3) Coal prices remained weak in Japan and North America, but rose strongly in Europe due to coal production grew robustly in the u s and Asia but fell in the European Union(EU) In recent years, people have witnessed a rapid growth o f non-fossil energy Global hydroelectric and nuclear output each saw the strongest increases since 2004 Hydroelectric output grew by 5.3%, with China accounting for more than 60% o f global growth due to a combination o f new capacity and wet weather 10 M a ste r Thesis Theoretical background Worldwide nuclear output grew by 2%, with three-quarters o f the increase coming from OECD countries French nuclear output rose by 4.4%, accounting for the largest volumetric increase in the world Other renewable energy sources continued to grow rapidly [ 1] Figure 3: Natural gas price (dollars/Btu) [1| Global biofuels production in 2010 grew by 13.8%, or 240,000 b/d, constituting one o f the largest sources of liquids production growth in the world Growth was driven by the US (+140,000 b/d, or 17%) and Brazil (+50,000 b/d, or 11.5%) Renewable energy used in power generation grew by 15.5%, driven by continued robust growth in wind energy (+22.7%) The increase in wind energy in turn was driven by China and the US, which together accounted for nearly 70% o f global growth These forms o f renewable energy accounted for 1.8% o f global energy consumption, up from 6% in 2000 [ 1] 1.1.2 Change in share o f world prim ary energy When looking at the share of world primary energy, oil, coal and natural gas are three main sources o f energy In the past 20 years, percentage o f oil in total primary energy consumption is reduced rapidly Energy crisis, high oil price and environmental problems are making people looking for new sources o f energy which is more sustainable Hydro and nuclear energy are popular non-fossil energy sources nowadays However, both o f them showed their disadvantages 11 M aster Thesis Theoretical background Especially after nuclear crisis in Japan, March 2011, people have to look for new clean and safe energy C ontributions to gro w th S hares o f w o rld p rim a ry en erg y 50% i| 2.5 9i ■ R enew ables* 40% 2m ■ Hydro H Nuclear 30% ■ Coal 20 % 1.0% ■ Gas 10% 0.59c Hydro M Oil 0 % 1970-1990- 20101990 2010 2030 Includes biofuets Figure 4: Shares of world primary energy |1] BP predicted that world primary energy consumption grew by 45% over the past 20 years, and is likely to grow by 39% over the next 20 years Global energy consumption growth averages 1.7% p.a from 2010 to 2030, with growth decelerating gently beyond 2020 Non-OECD energy consumption is 68% higher by 2030, averaging 2.6% p.a growth from 2010, and accounts for 93% o f global energy growth OECD energy consumption in 2030 is just 6% higher than today, with growth averaging 0.3% p.a to 2030 From 2020, OECD energy consumption per capita is on a declining trend (-0 % p.a.) The fuel mix changes relatively slowly, due to long asset lifetimes, but gas and non-fossil fuels gain share at the expense o f coal and oil The fastest growing fuels are renewables (including biofuels) which are expected to grow at 8.2% p.a 2010-30; among fossil fuels, gas grows the fastest (2.1% p.a.) [1] One o f renewables source o f energy is waste Waste to energy is a hot topic in many countries It not only provides a non-fossil energy source but also solves 12 M aster Thesis 3.1.2 R esu lts and discussion Temperature Temperature is an important parameter in RDF producing method Required temperature o f composting step is over 60°C to ensure sanitariness o f RDF product Furthermore, in high temperature condition, waste is dried faster which lead to shorten producing time As mentioned above, temperature was measured twice a week in all barrels The result is shown in Figure 16 Days Figure 16: Temperature in stabilization barrels As regards, temperature in all barrels is higher than atmosphere temperature However, there was not much difference in temperature between waste heaps The increase of temperature is clearly seen in the fourth week On the other hand, experiment was carried out in March when Hanoi's temperature raises (figure 16) Therefore temperature in barrels also increases during stabilization process In theory, temperature o f composting waste starts increasing from day 10 to day 20 or 30 and the highest temperature changes from 45°C to 70°C depending on C:N ratio (figure 17) This temperature curve is built while atmosphere temperature is considered unchanged However, in reality, atmosphere temperature range can be more than 20°C during stabilization process especially 39 M aster Thesis when the R esu lts and discussion season changes Therefore, differences between composting temperature and atmosphere temperature were evaluated in figure 18 Carbon:Nitrogen Ratio Effects on Composting Days of decomposition Figure 17: Composting temperature depending on C:N ratio Temperature curves from this study can be divided to phases as expected from theory Phase was when micro-organism developed Phase was when micro­ organism activities were strongest It also leaded to highest temperature difference And phase was when micro-organism reduced However, max temperature is expected to occur in the second week according to theory In this research, temperature differences reached maximum in the fourth week Other wise, maximum temperature in all barrels are lower than 35°C while the maximum temperature in theory is over 40°C and it can be 70°C in ideal condition This can be explained by following possibilities Firstly, due to research condition, waste amount was only 18 kg each barrel It is quite small in comparison with other studies; hence the surface-to-volume ratio o f our batch is much higher, leading to more heat loss Secondly, the equipment used in this study was quite simple, it could not ensure good aerobic condition during composting, thus microbial activity was ineffective Moreover, thickness and thermo-conduction o f barrel wall are also reasons for losing heat A hn’s research has proven that the wall conduction accounted to 62% o f the heat loss [3] 40 M aster Thesis R esu lts and discussion Figure 18: Temperature differences in stabilization barrels In practice, large amount o f compost waste is expected to give better result; however, further research in pilot scale is needed to prove it In addition, wall conduction is required to be considered when producing RDF by DSP Twolayer insulation wall is a suggestion which was used in Ha Nam 114) 3.1.3 Leachate volume In composting process, organic matter is broken down by micro-organism generating heat and leachate water In the boundary o f this study, only volume o f leachate was monitored twice a week (Figure 19) Once a week, waste was taken out to mix with air It resulted on micro-organism activities which can be observed by high amount o f leachate in the next days Figure 19 shows that leachate volume o f barrel was not change much after air mixing It can be explained by low bio-waste content in barrel therefore microorganism activities did not change much Barrel and contain higher percent o f bio-waste which result higher amount o f leachate 41 M aster Thesis R esults and discussion Figure 19: Leachate volume 3.1.4 Water content Sample was taken once every seven days except day 35 Figure 20 shows water content o f samples during composting step All o f them had more than 60% water content at the beginning During the first three weeks, percentage o f water in waste body showed almost no change It is because there are processes concomitantly occur The first is drying process in which heat from micro-organism is expected to dehydrate waste body Secondly, water was producing from degradation activity which added more moisture to waste body Water content dropped in the fourth week This result is well-matched with temperature result In the same period, higher temperature was observed which provided more heat for drying process In the last two week, water content in samples was stable at the range o f 35 to nearly 50% This is not good result when comparison w ith water content o f RDF product in Ha Nam and Germany ( 10 MJ/kg-RDF) Table 17: C emission from combustion process (kg/kg RDF) R1 R2 R3 C02 co C02 co C02 co C02 C02 C02 fossil bio total fossil bio total fossil bio total 48 M aster Thesis Bio­ R esu lts and discussion 0.044 0.266 0.310 0.021 0.130 0.152 0.033 0.203 0.236 Nylon 0.148 0.015 0.163 0.677 0.070 0.747 0.395 0.041 0.436 Paper 0.034 0.216 0.250 0.026 0.165 0.190 0.030 0.192 0.222 Textile 0.027 0.011 0.038 0.020 0.008 0.029 0.024 0.010 0.034 Total 0.252 0.509 0.761 0.744 0.374 1.118 0.482 0.446 0.928 waste C 2-eq emission by auxiliary consumption LHV o f all samples is higher than 10 MJ per kg fuel which is higher enough to ensure combustion without the necessity o f auxiliary firing The small amount o f fossil fuels for start-up and shut-down procedures are not taken in to account Therefore, CO2 emission in this part is considered zero N20 emission In the same way with N 20 emission in pre-treatment process N20 emission data in combustion was taken from references N 20 emission which was calculated for German waste is estimated 3.41kgC 02-eq./t-RDF (GW PN20 = 298) [9] 3.3.3 Total GHGs emission Total GHGs emission is sum o f GHGs emission in 3.3.1 and 3.3.2 then converted to kg C 2/MJ This unit is used to compare GHGs emission from RDF samples and fossil fuel (Figure 23) As mentioned above, emission of C bio is considered neutral and not count when estimating for global effect Therefore, when comparison, two terms are considered: • Total GHGs emission = C 2fossil emission + N 20 emission + C 2bio emission; • And emission factor (EF) = C 2fossil emission + N 20 emission From figure 23, it can be seen that total GHGs emission o f RDF sample is lower than emission from coal and higher than emission from oil and gas However, when comparing emission factor, all RDF samples have lower emission factor than fossil fuel Therefore, it is obvious that RDF is friendlier with environment than fossil fuel 49 M aster Thesis R esu lts a n d discussion 0.12 ■ C bio N20 emission 0.1 ■ C emission ■ C fossil 08 06 0.04 02 R1 R2 R3 Braun coal Hard coal Coke Oil Gas Figure 23: GHGs emission from RDF sample compare with fossil fuel (kg C 2.cq /MJ) |9| As regarding, when comparing between samples, R2 has highest emission factor R1 and R3 has similar emission factor however, R3 shows better result when considering total GHGs emission 50 M aster Thesis Conclusion C o n c l u sio n Within this study RDFs produced by DSP method from different input waste compositions were investigated; as a result several outcomes could be obtained: • Monitoring result show that waste amount plays an important role in drying process In this study, only small amount o f waste was used which leads to low efficiency Therefore, further study in larger scale is required to estimate correctly efficiency o f this method • Qualities of RDF samples were compared R3 sample which has medium ratio bio-waste to nylon waste (4:1) shows best result in all parameters: heating value, water content and emission factor R1 which has highest ratio bio-waste to nylon (14:1) show good result with water content and EF However, heating value o f R1 is lower than R2 and R3 Oppositely, R2 (bio-waste:nylon = 1.5:1) which has higher heating value shows not good water content and EF result • In spite of giving different heating value and EF results, all RDF samples have higher heating value than MSW and similar with fossil fuel More over, EF of all samples is lower than EF o f fossil fuel Therefore, possibility o f RDF substitution can be proven Based on those conclusions, some recommendations can be suggested for further studies: • Larger pilot researches should be carried out with enhancement in equipment capacity, ventilation and thermo-insulation • Additional experiments can be performed to investigate intensively the relationship between waste composition and final product's characteristics (e.g heating value and moisture) in Vietnam The resulted database could be used as a reference for estimating the RDF production possibility in different regions of Vietnam • The thesis focused only in some major emission gases (i.e NiO and COi) and they were not measured practically There is a need o f a full assessment o f gases that could affect the environment 51 M aster Thesis A ppendix R eferences English ] Statistical review o f world energy 2011, London England: BP, Inc World Development Indicators 2011 2011: World Bank Publications Ahn U.K., T.L Richard, and H.L Choi, Mass arid thermal balance during composting o f a poultry manure— Wood shavings mixture at different aeration rates Process Biochemistry, 2007 42(2): p 215-223 Alter, H., The history o f refuse-derived fuels Resources and Conservation 1987 15(4): p 251-275 ’ Bilitewski, B., G Hărdtle, and K Marek, Waste management 1997: Springer Châu Đ.N., Investigation the suitable parameters fur Refuse Derived Fuel production in Vietnam 2009, Hanoi University of Science Dezhen Chen, X.Z.a.G.Z Life Cycle Assessment o f RDF Production from aged M Sw and its utilization system, in International Conference on Sustainable Solid Waste Management 2007 Chennai, India Gendebien, A., et al., Refuse derived fuel current practice and perspectives 2003, European Commission Giang, N.T.H Potentials and Limitations o f Energy Recovery from Municipal Solid Waste (MSW) in Vietnam, in Institute o f Waste Management and Contaminated Site Treatment 2011, Dresden University of Technology: Dresden 10 Giang, S.S.B.B.N.T.H Characterisation and potential o f municipal solid waste in Hanoi for energy utilisation, in Waste to Energy in the City o f tomorrow 2010 Hanoi 11 Hamel, s., et al., Autothermal two-stage gasification o f low-density wastederived fuels Energy, 2007 32(2): p 95-107 12 Hernandez-Atonal, F.D., et al., Combustion o f refuse-derived fuel in a fluidised bed Chemical Engineering Science, 2007 62(1-2): p 627-635 13 Kawai, K., Accuracy o f municipal solid waste data in Vietnam, in The SthWorkshop on GHG Inventories in Asia (WGIA8) 2010: Lao PDR 14 N.T.D.Trang, N.B., N.G.Long “Municipal Solid Waste Treatment-Experiences getting from practice in Waste-to-Resources 2009, III International Symposium MBT and MRF 2009 Hanover, Germany 52 M aster Thesis A ppendix 15 Papageorgiou, A., J.R Barton, and A Karagiannidis, Assessment o f the greenhouse effect impact o f technologies used for energy recovery from municipal waste: A case for England Journal of Environmental Management, 2009 90(10): p 2999-3012 16 Rada, E.C Ragazzi M Panaitescu, V and Apostol, T MSW bio-drying and bio-stabilization: An experimental comparison, in /SIVA Conference- Towards Integrated Urban Solid Waste Management System Buenos Aires: International Solid Waste Association 17 Rotter V.S., et al., Material flow analysis o f RDF-production processes Waste Management, 2004 24(10): p 1005-1021 18 Solomon, s., I.p.o.c Change, and I.P.O.C.C.W.G I., Climate change 2007: the physical science basis : contribution o f Working Group to the Fourth Assessment Report o f the Intergovernmental Panel on Climate Change 2007: Cambridge University Press 19 Sven, s., Analyze of RDF production in Vietnam 2010, co-operation between TU Dresden, Germany and Hanoi University of Science Vietnamese 20 Bảo cáo môi trường quốc gia 2005 2006, Bộ Tài nguyên Môi trường (MONRE) 21 Báo cảo mỏi trường quốc gia 2010 2011 Bộ Tài nguyên Môi trường (MONRE) 22 Nghiên cứu, xác định hệ số phút thai (EF) cua lưới điện Việt Nam 2009, Trung tâm Bảo vệ tầng ơ-zơn, Cục Khí tượng Thuỷ văn Biến đổi khí hậu, Bộ Tài ngun Mơi trường: Hanoi 23 Tông điểu tra dân sổ nhà Việt Nam năm 2009 2009, Tổng cục thống kê (General Statistic Office) 24 Xây dựng mơ hình triển khui thí điểm việc phân loại, thu gom xử lý rác thải sinh hoạt cho khu đô thị 2008, Cục Bảo vệ môi trường (VEPA) 53 ... solid waste management is still a challenge in Vietnam One reason is that waste management in Vietnam lacks separation at source To cope with those problems, energy from waste is being studied and. .. is mainly used for small furnace in the same area Heating value o f RDF product from MBT.CD.08 method is similar with heating 28 M aster Thesis Theoretical background value o f charcoal and much... Once a week, waste was taken out to mix with air and then put back into the barrel At the same time, waste sample was taken to measure water content Waste had been kept in the barrel until water