OF AIR POLLUTANTS FROM BIOMASS GASIFIER BASED SYSTEMS R. UMA DOCTOR OF PHILOSOPHY

Transcription

1 MEASUREMENT AND AS OF AIR POLLUTANTS FROM BIOMASS GASIFIER BASED SYSTEMS by R. UMA Centre for Energy Studies Thesis submitted in fulfillment of the requirements of the degree of DOCTOR OF PHILOSOPHY to the INDIAN INSTITUTE OF TECHNOLOGY, DELHI HAUZ KHAS, NEW DELHI (INDIA) DECEMBER, 2004

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3 CERTIFICATE It is hereby certified that the thesis entitled "Measurement and Assessment of Air Pollutants from Biomass Gasifier Based Systems", which is being submitted by Ms.R Uma is entirely the result of her own efforts. The work was carried out under our supervision and the results contained in it have not been submitted in part or full to any other university or institute for award of any degree/diploma. Dr. Tara Chandra Kandpal Professor Centre for Energy Studies Indian Institute of Technology Delhi Hauz Khas New Delhi (INDIA) Dr V V N Kishore Senior Fellow The Energy and Resources Institute Lodi Road New Delhi (INDIA)

4 ACKNOWLEDGEMENTS I express my sincere gratitude to my supervisors Prof. T.C. Kandpal and Dr. VVN Kishore for their inspiration, guidance and support. I would like to thank my colleagues Ms. Kusum Lata, Dr Sanjay Mande, Mr. Santosh Raghavan, Mr. Raman and Mr. Mohit for their assistance with the experiments, laboratory analysis and advice. I acknowledge the support of all field staff particularly Mr. Jacob George, Mr. Joseph, Mr. Vellai Kannu and Mr. Lal Babu. I would like to thank my fellow researchers at the Centre for Energy Studies, IIT Delhi Mr. Atul Chamola, Mr. Pallav Purohit and Mr. B. Chandrasekar for their help and advice. I wish to thank the support of Dr. R K Pachauri, Director General, TERI and Ms. Preety Bhandari, TERI. I thank Mr. Ritesh Kumar Jha for his secretarial assistance. I appreciate and acknowledge the support of my husband Mr. N. Rajarathnam, who always renders his support, help and encouragement. I appreciate my children Shreenandan and Shivanandan for their understanding and cooperation. I acknowledge the support of my mother who always stood firm behind me during my emotional needs and blessed me with her love. My thanks are also due to my brother Mr. Ashok Gautham and my nephew Mr. S. Dhanapal. d, (R LIMA) ii

5 ABSTRACT This thesis presents the results containing measurements of carbon dioxide (CO2), carbon monoxide (CO) hydrocarbons (HC), methane (CH4), sulphur dioxide (SO2), oxides of nitrogen (N0x) and particulate matter (PM) emissions from various biomass gasifier based systems. The systems tested in the study include small-decentralized power generation systems operating on diesel alone, dual fuel (diesel and producer gas mode) mode and producer gas alone mode; biomass gasifier based thermal systems for small and medium scale industries and biomass gasifier based cooking devices. Emission factors for major air pollutants have been estimated from the concentration of pollutants measured in this study. It has been found that use of producer gas for engine operation reduces SO2, NO and PM emissions, whereas the CO emissions increase with the use of producer gas. It was also observed that the emissions increase at low load conditions. The study highlights the need for developing suitable engines for operation with producer gas. The emission characteristics of thermal systems depend on the burner design and operational characteristics. Emissions of products of incomplete combustion are lower in closed combustion burners, which are used for high temperature applications than in case of combustion of producer gas in open burners. It has been observed that the gasifier based cooking devices have high overall thermal and nominal combustion efficiency with low emissions as in the case of clean gaseous fuels such as LPG and biogas. The study also presents the greenhouse gases (GHGs) emission mitigation potential of various biomass gasifier based systems. iii

6 TABLE OF CONTENTS Certificate Acknowledgements Abstract Table of Contents List of Figures List of Tables Nomenclature Chapter 1 Introduction Chapter Energy Consumption Pattern in India 1.2 Renewable Energy Scenario in India 1.3 Biomass Utilization and Conversion Technologies 1.4 Biomass Gasification Classification of biomass gasifiers Applications of biomass gasifiers 1.5 Environmental Aspects of Biomass Energy Use 1.6 Literature Survey 1.6.1Studies on biomass gasifier Studies on emissions from biomass combustion devices 1.7 Present Study Experimental Methodology, Measurement Techniques and Estimation Methods Experimental Details 2.1 iv

7 2.2 Flue or Exhaust Gas Sampling Mcthods Sampling from stack or exhaust pipe Sampling from unvented devices Measurement Techniques Particulate matter Measurement of gaseous pollutants Gasifier feedstock and producer gas consumption Diesel replacement rate Calorific value Electric power output Quality control in sampling and measurements Estimation of thermal performance and emission factors Thermal efficiency Estimation of emission factors 2.12 Chapter 3 Emission Characteristics of Biomass Gasifier Based Decentralized Electricity Generation Systems 3.1 Introduction Methodology System description Experimental details Results and Discussion Pollutant concentration Emission factors Specific energy consumption Diesel replacement rate 3.11

8 3.4 Concluding Remarks 3.12 Chapter 4 Emission Characteristics of Biomass Gasifier Based Thermal Systems for Industrial Applications 4.1 Introduction Methodology System description Experimental details Results and Discussion Pollutant concentration Emission factors Concluding Remarks 4.11 Chapter 5 Emissions From an Improved Household Cookstove and a Community Cooking Device 5.1 Introduction Methodology Description of the systems tested in the study Method of sampling and analysis Results and Discussion Emission ratio of product of incomplete combustion to 5.6 Carbon dioxide Emission factors Concluding Remarks 5.9 Chapter 6 Estimation of Greenhouse Gas Emission Mitigation Potential of Biomass Gasifier Based Systems 6.1 Introduction Methodology 6.2 vi

9 6.2.1 Power generation system Thermal system for industrial applications Domestic cooking Results and Discussion Power generation system Thermal system for industrial applications Biomass gasifier based improved cookstove for a 6.9 household 6.4 Concluding remarks 6.9 Chapter 7 Conclusion and Recommendation 7.0 References R-1 Aendix pp 1 Indian emission norms for diesel engines Appendix 2 A Schematic of tile manufacturing process where gasifier based A-2 thermal system (TS-2) is installed Appendix 3 Energy flows in a typical wood-fired cooking stove A-3 Appendix 4 Indoor concentrations of health damaging pollutants from a typical A-4 wood-fired cook stove Appendix 5 Greenhouse gas emissions from a typical biomass cookstove A-5 Appendix 6 Global warming potential (GWP) of major greenhouse gases A-6 A-1 vii