Tài liệu Comparative casestudy of biogas utilization from livestock manure in Vietnam (focussing on CO2 balance)

TRƯƠNG THỊ KIM DUNG COMPARATIVE CASE STUDY OF BIOGAS UTILIZATION FROM LIVESTOCK MANURE IN VIETNAM (FOCUSSING ON CO2 BALANCE) Field: waste management and contaminated site treatment MASTER THESIS Supervisor: Dr.-Ing. Christoph Wünsch Dresden, September, 2011 ACKNOWLEDGEMENT Firstly I would like to thank to the Hanoi University of Science, Vietnam National University and Techniche Universtät Dresden, Institute of Waste Management and Contaminated Site Treatment, whose have established a good study program for us to learn a good new field of environment. I would like to thanks to Prof. Bernd Bilitewski, Prof. Nguyen Thi Diem Trang and Dr. Hoang Van Ha, whose always keep an eye on our study and help us so much. My sincerely thanks to my supervisor Dr. Christoph Wünsch, Dipl. Veit Grundmann , who guide and help me hold-heartedly during the time I did the thesis. And I also want to thanks to Dr. Catalin Stephan and Dipl.Hoang Mai. I still remember our discussion, small parties as well as your encouragements. It helps me more selfconfident in my ability. Finally I want to thanks so much to my family. You are my motivation to overcome difficulties in my life. ABSTRACT From 2003 Livestock Production Department under Ministry of Agriculture and Rural Development - MARD cooperates with Netherlands Development Organization – SNV to deploy of domestic biogas program for livestock production in rural area. The program not only solve environment problems in terms of pollution and improve rural life quality, it also contributes to greenhouse gas reduction considerably. At household scale, biogas is utilized mostly for cooking and such tons of greenhouse gas can be reduced from one household per year, mostly from correct livestock manure management and fossil fuel substitution. At farm scale, biogas can be utilized for electricity generation, thousands KWh of electricity can be produced and such thousand tons of greenhouse gas can be reduced per farm per year. It should be encouraged to apply this treatment method for all kinds of livestock of the country. The greenhouse gas emission reduction will be much more significantly, contribute to meet the aim of the Kyoto Protocol “to achieve stabilization of atmospheric concentration of greenhouse gases at a level that would prevent dangerous anthropogenic interference with the climate system” that Vietnam signed in. Contents INTRODUCTION ............................................................................................................ 6 I. BACKGROUND ....................................................................................................... 1 1.1. Greenhouse effects and climate change ............................................................. 1 1.1.1. Greenhouse effects .......................................................................................... 1 1.1.2. Climate change ............................................................................................ 3 1.2. Greenhouse gas emission situation in Vietnam.............................................. 7 1.3. Livestock growing situation in Vietnam .......................................................... 12 II. OVERVIEW ON BIOGAS ..................................................................................... 16 2.1. Scientific theory of anaerobic digestion (biogas formation) ....................... 16 2.2. Composition of biogas .................................................................................... 19 2.3. Substrates for anaerobic digestion ................................................................ 22 III. BIOGAS PROJECT IN VIETNAM .................................................................... 22 3.1. Project overview ................................................................................................. 22 3.2. Technology of anaerobic digester used in the project .................................... 23 3.2.1. Structure of the anaerobic digester ................................................................ 23 3.2.2. Operation of the biogas plant ........................................................................ 25 3.2.3. Treatment efficiency of biogas plants ........................................................... 26 3.3. Utilization of outputs from biogas plants ............................................................ 27 3.3.1. Utilization of biogas ...................................................................................... 27 3.3.2. Utilization of bio-slurry ................................................................................. 31 IV. CASE STUDY ......................................................................................................... 35 4.1. Project scenario .................................................................................................. 35 4.2. Methodology ....................................................................................................... 36 4.2.1. GHG reduction from manure management ................................................... 36 3.2.2. GHG reduction from the fossil fuel substitution in thermal application or electricity generation ............................................................................................... 42 3.2.3. GHG reduction from chemical fertilizer substitution by bio-slurry.............. 46 4.3. Calculation and results ...................................................................................... 48 4.3.1. GHG reduction at household scale ................................................................ 48 4.3.2. GHG reduction at farm scale ......................................................................... 64 4.4. Outlook ............................................................................................................... 67 IV. CONCLUSION .................................................................................................... 71 ABBREVIATION bn Billion e equivalent DM Dry matter (% Ho,n Calorific value (kWh/Nm3) Hu,n Calorific value (kWh/Nm3) IPCC Intergovernmental Panel on Climate Change GHG Greenhouse gas LFG Landfill gas MARD Ministry of agriculture and rural development MNVOC Non-methane volatile organic compounds SNV The Netherlands development organization VS Volatile solid UNFCCC United Nations framework Convention on Climate Change or g/l) LIST OF TABLES Table 1: National greenhouse gas emission inventory by sector of Vietnam in 2000 ..... 7 Table 2: greenhouse gas emission from agriculture sector .............................................. 8 Table 3: total primary energy consumption by type of energy ........................................ 9 Table 4: GHG emission from fuel combustion by type of fuel in 2000 ........................ 10 Table 5: GHG emission from fuel combustion by sub-sector ....................................... 10 Table 6: GHG emission from fuel combustion by type of gas ...................................... 11 Table 7: Livestock population growth (thousands)........................................................ 13 Table 8: livestock and milk production, million metric tons ......................................... 14 Table 9: total livestock waste (solid) generation in 2006 .............................................. 16 Table 10: Environmental requirements .......................................................................... 19 Table 11: Biogas composition ........................................................................................ 19 Table 12: Biogas composition compared with natural gas ............................................ 20 Table 13: General energy characteristics of biogas ....................................................... 21 Table 14: Treatment efficiency of biogas plants ............................................................ 26 Table 15: Limited parameters for surface water quality according to the National technical regulation 2008 ............................................................................................... 27 Table 16: comparative values of biogas and other fuels ................................................ 28 Table 17: consumption of biogas and kerosene fuel in lighting according to the experience of the Institute of Energy ............................................................................. 30 Table 18: Nutrient concentrations in the bio-slurry ....................................................... 32 Table 19: concentration of some heavy metals in bio-slurry ......................................... 33 Table 20: nutrient contents in compost fertilizer made from bio-slurry and agricultural waste ............................................................................................................................... 34 Table 21: benefits from application of bio-slurry in agriculture in some provinces ..... 35 Table 22: input parameters for methane emission calculation from the baseline scenario (unrecoverable anaerobic lagoon) .................................................................................. 49 Table 23 input parameters for indirect nitrogen oxide emission calculation from the baseline scenario (unrecoverable anaerobic lagoon) and project scenario (biogas plant) ........................................................................................................................................ 51 Table 24: result of GHG emission reduction from manure management ...................... 52 Table 25: combustion efficiencies of combustion equipments with different fuels ...... 53 Table 26: GHG emission factor of coal ......................................................................... 54 Table 27: input parameters for GHG emission reduction calculation from fuel substitution in thermal application for at household scale. ............................................ 54 Table 28: GHG reduction results for a household growing 6 pigs ................................ 56 Table 29: Emission factors for stationary combustion in the residential and agricultural/forestry/fishing/farms ................................................................................. 58 Table 30: Results of GHG reduction in case different fossil fuel used in absence of the project ............................................................................................................................. 59 Table 31: GHG emission reduction according to population of livestock (pig) ............ 61 Table 32: the utilized biogas yield according to population of livestock (pig) ............. 63 Table 33: GHG reduction for a farm growing 100 pigs with utilization of biogas for electricity generation ...................................................................................................... 66 Table 34: input parameters for GHG emission reduction calculation from biogas destruction in the outlook ............................................................................................... 67 Table 35: The result of GHG emission reduction from biogas destruction in the outlook ........................................................................................................................................ 68 Table 36: input parameters for GHG emission reduction calculation from nitrogen oxide emission reduction in the outlook ........................................................................ 68 Table 37: The result of GHG emission reduction from nitrogen emission reduction in the outlook ...................................................................................................................... 69 Table 38: The result of GHG emission reduction from manure management in the outlook ............................................................................................................................ 69 Table 39: input parameters for GHG emission reduction calculation fuel substitution in thermal application in the outlook.................................................................................. 70 Table 40: GHG emission reduction calculation fuel substitution in thermal application in the outlook.................................................................................................................. 70 Table 41: Total GHG emission reduction in the outlook ............................................... 71 LIST OF CHARTS Chart 1: GHG reduction for a household growing 6 pigs with utilization of biogas for cooking purpose ............................................................................................................. 57 Chart 2: GHG reduction in case different fossil fuel used in the absence of the project ........................................................................................................................................ 60 Chart 3: GHG emission reduction according to number of livestock ............................ 62 Chart 4: GHG reduction for a farm growing 100 pigs with utilization of biogas for electricity generation ...................................................................................................... 66 LIST OF FIGURES Figure 1: The greenhouse effect principle ....................................................................... 3 Figure 2: changes in temperature, sea level and Northern Hemisphere snow cover ....... 5 Figure 3: National greenhouse gas emission inventory by sector of Vietnam in 2000 .. 8 Figure 4: Growth rate of pork production ...................................................................... 15 Figure 5: the anaerobic digestion process ...................................................................... 18 Figure 6: Types of fixed dome biogas plant used in the project are KT1 and KT2 ...... 24 Figure 7: two limit stages of fixed dome plant .............................................................. 25 Figure 8: diagram of biogas burner ................................................................................ 27 Figure 9: Structure of biogas lamp ................................................................................. 29 Figure 10: A biogas water boiler device ........................................................................ 31 Figure 11: Project scenario............................................................................................. 35 Figure 12: baseline scenario boundary of GHG reduction source: biogas destruction . 38 Figure 13: project scenario boundary of GHG reduction source: biogas destruction ... 39 Figure 14: Baseline scenario boundary of GHG reduction source: fossil fuel substitution in thermal application ................................................................................. 43 Figure 15: project scenario boundary of GHG reduction source: fossil fuel substitution in thermal application ..................................................................................................... 43 Figure 16: Baseline scenario boundary of GHG reduction source: fossil fuel substitution in electricity generation .............................................................................. 44 Figure 17: Project scenario boundary of GHG reduction source: fossil fuel substitution in electricity generation .................................................................................................. 45 Figure 18: baseline scenario boundary of GHG reduction source: chemical fertilizer substitution ..................................................................................................................... 47 Figure 19: project scenario boundary of GHG reduction source: chemical fertilizer substitution ..................................................................................................................... 47 INTRODUCTION Above the environment pollution problems from the rapid growing in livestock production without livestock manure treatment, the situation of lack of energy, and the overuse of chemical fertilizer production for crop production. From 2003 Livestock Production Department under Ministry of Agriculture and Rural Development MARD cooperates with Netherlands Development Organization – SNV to deploy of domestic biogas program to solve the short term of environment problems and also have the long term objective of improving the livelihood and quality of life of rural farmers in Vietnam. Until now there are more than 106000 biogas systems constructed in over 50 provinces nationwide, millions tons of livestock manure are treated. There are also some evaluation reports on economical and social effects. But there isn’t any detail report evaluating on environmental effects, especially greenhouse gas reduction from that project. The aim of this research is the detail assessment of GHG emission balance from livestock manure treatment method by anaerobic digesters (biogas plants) in the project to provide the reference data about the benefits of that project in term of GHG emission balance. I. BACKGROUND 1.1. Greenhouse effects and climate change 1.1.1. Greenhouse effects “The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface, energy is transferred to the surface and the lower atmosphere. As a result, the temperature there 1 is higher than it would be if direct heating by solar radiation were the only warming mechanism” http://en.wikipedia.org/wiki/Greenhouse_effect From 1827, Joseph Fourier recognized the importance of the greenhouse effect for the Earth’s climate. He emphasized that the atmosphere is relatively transparent to solar radiation, but highly absorbent to thermal radiation and that this preferential trapping is responsible for raising the temperature of the Earth’s surface [Isaac M. Held, Brian J. Sodden, 2000]. “The natural greenhouse effect means the short-wave energy from the sun is absorbed at the earth’s surface and reradiated in the form of infrared Chart (long wave) radiation. The greenhouse gas (some of low concentrate gases in atmospheric notably CO2, CH4, NOx, CO, etc.) absorb and emit long wave radiation. The increase in the atmospheric concentration of GHG leads to an incremental absorption and emission of long-wave radiation. All of them would result in a warming of the lower atmosphere and the surface of earth. This effect is referred as “greenhouse effect”. Human beings and most other living creatures can not survive without Natural greenhouse effect. The greenhouse effect keeps the temperature of biosphere stable and filters some harmful radiations and hence protects the ecological system” [Jia Xiaodong, 2009] Because of influence from human activities, greenhouse gas is increased, leading to enhanced greenhouse effect and climate change. Expressions of the climate change include temperature change in global scale, sea level rise, precipitation change and the increase of extreme weather events [IPCC, 2008]. 2 Figure 1: The greenhouse effect principle Source: http://en.wikipedia.org/wiki/Greenhouse_effect 1.1.2. Climate change * Definitions of climate change The definitions of climate change are different of the Intergovernmental Panel on Climate Change (IPCC) and the United Nations Framework Convention on Climate Change (UNFCCC). According to IPCC, “the climate change refers to a change in the state of the climate that can be identified (e.g. using statistical tests) by changes in the mean and/or the variability of it property, and that persists for an extended period, typically decades or longer. It refers to any change in climate over time, whether due to natural variability or as a result of human activity”. 3 The climate change according to UNFCCC is a change of climate that is contributed directly or indirectly to human activity that alters the composition of the global atmosphere and that is in addition to natural climate variability observed over comparable time periods [IPCC, 2008] * Climate change over the world Global warming is now evident from increases of global air, ocean temperatures and widespread melting of ice and snow and rising global sea level. According to the instrument record of global surface temperature from 1850, the eleven years of the rank from 1995 to 2006 is the warmest years [IPCC, 2008]. The linear trend of the global average temperature in the same long period of 100 years from 1906 to 2005 is 0.74 [0.56 to 0.92], higher than the 100-year period from 1901 to 2000 that is 0.6 [0.4 to 0.8]. The linear warming trend over the 50 years from 1956 to 2005 (0.13 [0.10 to 0.16]°C per decade) is nearly twice higher than the period of 100 years from 1906 to 2005. [IPCC, 2008] 4 Figure 2: changes in temperature, sea level and Northern Hemisphere snow cover Source: [IPCC, 2008] The temperature increase has taken place at global scale. The increase rate of temperature in Acrtic is almost twice higher than the global average rate in the past 100 years. Land regions are warmed faster than the oceans. The increase of sea level is correlative with warming of the earth (figure 2). The sea level rose have been clearer in recent years. The global sea level rise rate from 1993 to 2003 is 3.1 [2.4 to 3.8] mm per year that is higher than the rate of 1.8 [1.3 to 2.3] of the period from 1961 to 2003 [IPCC, 2008]. That increase is contributed by the 5 thermal expansion of the oceans (57%), by the decreases in glaciers and ice caps (28%) and losses from polar ice sheets (15%) [IPCC, 2008]. The decreases of snow and ice are also relative with warming of the earth (figure 2). The annual average sea ice in Arctic has shrunken about 2.7 [2.1 to 3.3]% per decade, and this number is higher in summers of 7.4 [5.0 to 9.8]% per decade. Glaciers and snow in mountains in both hemispheres also have declined. The frozend ground extent in the Northern Hemisphere has decreased about 7% since 1900. From the 1980s up to now, the temperature at the top of the permafrost layer in Arctic increased by up 3°C [IPCC, 2008]. The precipitate also changed much in many regions. “Globally, the area affected by drought has likely increased since the 1970s”. [IPCC, 2008] The extreme changes of the weather have happened frequently over the last 50 years: “it is very likely that cold days, cold nights and frosts have become less frequent over most land areas, while hot days and hot nights have become more frequent. It is likely that heat waves have become more frequent over most land areas. It is likely that frequency of heavy precipitation events has increased over most areas. And it is likely that the incidence of extreme high sea level has increased at abroad range of sites worldwide since 1975”[IPCC, 2008]. The average temperature in the Northern Hemisphere during the second half of the 20th century is higher than any 50-year period in the last 500 years and is the highest in at least past 1300 years [IPCC, 2008]. * Climate change in Vietnam Vietnam is one of the countries that are suffered mostly of climate change. According to recent studies in Vietnam, the average temperature has increased about 0.1 10C per decade. The weather seems severer. The temperature of beginning months of the winter decreases but increases in months of the end of the winter. Seasonal rainfall decreases in July and August and increases in September, October and 6 November. The sea level has risen at average rate about 2.5 – 3 cm per decade. Storms, floods and droughts have taken more frequently recent years. Because of the climate change, the sea water level of Vietnam is forecasted to be raised by 33 cm in 2050 and 45 cm in 2070. And if the sea level increases up to 90 cm in 2100, a huge area in the Red River Delta, north central coastal area and Cuu Long delta area will be submerged under water [MARD, SNV, 2007]. 1.2. Greenhouse gas emission situation in Vietnam Vietnam has contributed around 151 million tons of CO2 equivalent in 2000 in which agriculture sector is the largest source (43.1%), then is from the energy sector (35.0 %) and at least from industrial sector (6.6 %) and from waste (5.3 %) as in the table 1 and figure 3. Table 1: National greenhouse gas emission inventory by sector of Vietnam in 2000 CO2 Sector CH4 N2 O (thousand (thousand (thousand CO2e (thousand Percentage (%) tons) tons) tons) tons) Energy 45,900.00 308.56 1.27 52,773.46 35.0 Industrial processes 10,005.72 0 0 10,005/72 6.6 0 2,383.75 48.49 65,090.65 43.1 11,860.19 140.33 0.96 15,104.72 10.0 Waste 0 331.48 3.11 7,925.18 5.3 Total 67,765.91 3,164.12 53.83 150,899.73 100 Agriculture Land use, land-use change and forestry 7 Source: [MONRE, 2010] Figure 3: National greenhouse gas emission inventory by sector of Vietnam in 2000 Source: [MONRE, 2010] In agriculture sector, sources of GHG emission are from rice cultivation, from livestock, agricultural soils and burning of agricultural residues as in the table 2. Table 2: greenhouse gas emission from agriculture sector Sector Enteric fermentation Manure management Rice cultivation Agricultural soils Burning of savannas Burning of agricultural residues Total CO2 CH4 N2 O CO2e Percentage (thousand (thousand (thousand (thousand (%) tons) tons) tons) tons) 368.12 7,730.52 11.9 164.16 3,447.36 5.3 1,782.37 37,429.70 57.5 45.87 14,219.70 21.8 9.97 1.23 4.46 590.67 0.9 59.13 1.39 50.28 1,672.63 2.6 2,383.75 48.49 54.74 65,090.65 100 Source: [MONRE, 2010] In energy sector, the table 3 shows the increasing primary energy consumption in recent years due to increasing energy demand. 8 Table 3: total primary energy consumption by type of energy: Unit: kilo tons of oil equivalent Year 2000 2001 2002 2003 2004 2005 2006 2007 Coal 4,372 5,024 5,517 6,562 7,344 8,376 9,045 9,736 7,917 8,415 9,616 10,490 12,082 12,270 12,184 14,234 Gas 1,441 1,566 2,151 2,776 4,255 4,908 5,239 5,976 Hydropower 4,314 5,573 5,569 4,422 4,141 3,835 4,619 5,179 Gasoline and Oil Noncommerical 14,191 14,297 14,399 14,694 14,734 14,794 14,860 14,870 energy Imported electricity Total 0 0 0 0 0 33 83 226 32,235 34,875 37,252 38,944 42,556 44,216 46,030 50,221 Source: [MONRE, 2010] Sources of GHG emission in energy sector are from fuel combustion, fugitive emission in course of extraction and transportation, in which mostly from fuel combustion that is 45.9 million tones of CO2, 68.4 thousand tones of CH4 and 1.27 thousand tones of N2O in 2000 as in the table 4, the table 5 and the table 6. 9