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Small Scale Biomass Gasification Technology in India

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Varshney etal./Journal of Engineering, Science and Management Education/Vol. 3, 2010/33-40 SMALL SCALE BIOMASS GASIFICATION TECHNOLOGY IN INDIA- AN OVERVIEW Rajiv Varshney*, J. L. Bhagoria**, C. R. Mehta*** Received: 5th Oct.2010 Revised:10th Nov..2010 Abstract The paper reviews the potential and status of biomass gasification technology used in India for thermal applications and power generation to meet the energy requirements. The gasifiers produced in India range from 5500 kW capacities for power generation. The Ministry of New and Renewable Energy (MNRE) has promoted the biomass gasification programme through subsidies. At present the cumulative installed capacity is 703 MW. The technoeconomic feasibility of gasification technology for thermal application has been favourable when compared with replacement of petroleum fuel. Mostly, the installed systems are dual fuel based and the fuel replacement varies from 5060 % at field level. A large amount of surplus crop residue is either burnt due to unavailability of space or remains underutilized due to various reasons. This crop residue can be utilized for power generation through gasification at a higher efficiency. Key Words: Biomass, gasification, gasifier INTRODUCTION The power produced from non renewable sources like coal and petroleum are not going to last for a long period due to their exhaustive nature. Further, the high price of petroleum products compels to search and develop renewable energy sources like solar, wind and biomass which are available in abundance in India. Nuclear energy production being a highly costly process, deter its use in daily activities. The installation of dams for hydel energy are not always possible. Tidal energy is a very localized energy source. Biomass is a clean and safe energy source. The energy from biomasss may be obtained either through biochemical reactions (biomethanation) or thermo- chemical reaction. Both the processes are practically feasible. The process for utilizing biomass to produce producer gas through thermo- chemical process is called gasification. This paper restricts presentation on biomass gasification. The term gasification, in its widest sense, covers the conversion of any carbonaceous fuel to a gaseous product with a useable heating value. This definition excludes combustion, because the product flue gas has no residual heating value. It does include the technologies of pyrolysis, partial oxidation, and hydrogenation. The dominant process is partial oxidation, which produces the fuel producer gas (otherwise known as synthesis gas or syngas) consisting of carbon monoxide and hydrogen in varying ratios, whereby the oxidant may be pure oxygen, air, and/or steam. Partial oxidation can be applied to solid, liquid, and gaseous Accepted: 20th Dec. 2010 feedstocks, such as coals, biomass, residual oils, and natural gas [13]. Figure 1 shows a schematic diagram of updraft and downdraft gasifiers alongwith the reactions occuring in each zone [14]. The process is usually carried out by using the heat from carbon oxidation to sustain the gasification reaction. The solid fuel is mixed with the oxidant (air or oxygen) to gasify the fuel. In some of the gasification reactions water or steam is added to control the reaction temperature. In actual practice, the details of this conversion are complicated, and multiple products besides CO and H2 are formed in the producer gas, such as CH4 and tars. Tars are complex mixtures of hydrocarbon materials that can condense on downstream side if not removed or further processed and utilized. Impurities in the solid feedstock (compounds of sulfur, nitrogen, chlorine, and others) will produce impurity species that need to be removed from the producer gas. Solid ash residue, the noncombustible material that is primarily the inorganic component of the fuel feedstock, must likewise be separated. The producer gas is usually cooled to allow impurity removal, providing sensible heat that can be used to raise steam for power generation, or chemical processes [12]. With gaseous and liquid hydrocarbons and alcohols as well as carbohydrate feedstock, there are many process options for producer gas and hydrogen production. They are steam reforming, partial oxidation, and autothermal reforming or oxidative steam reforming. With solid feedstock such as coal, petroleum coke, or biomass, there are various gasification processes that involve endothermic steam gasification and exothermic oxidation reaction to provide the heat in situ to sustain the reaction process [11]. Producer gas can be used to run reciprocating engines. However, due to the large size of gasifier it is primarily used for stationary engines or power generating system. Furthermore, it is being used successfully in gas turbines though there is still some scope of improvement in the technology. Among the various types of fuel cells available, solid oxide fuel cells have shown the most promising performance for efficient operation on producer gas. The availability of biomass in India is estimated to be about 1000 million tonnes per year covering residues from agriculture, forestry, and plantations. Major agricultural residues include rice husk, rice straw, bagasse, sugar cane tops and leaves, groundnut shells, cotton stalks, sunflower stalks, mustard stalks, piegeon pea stalks etc. It has been estimated that about 70-75% of these wastes are used as fodder, as fuel for domestic cooking and for other economic purposes *Research Scholar, Maulana Azad National Institute of Technology, Bhopal. E-mail : rajiv_varshney@rediff.com ** Associate Professor, Maulana Azad National Institute of Technology, Bhopal ***Principal Scientist, Central Institute of Agricultural Engineering, Bhopal 33

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Journal of Engineering, Science and Management Education leaving behind 120–150 million tonnes of agricultural residues per year which could be made available for power generation. Lot of Research and Development work has been carried in the country in the field of gasification to solve various operational problems like removal of tar, cooling of the gas to suit to work in IC engines, utilization of byproducts of gasification system, evaluation of IC engines on producer gas. Fig. 1 : Schematic diagram of (a) updraft and (b) downdraft gasifiers [14] BIOMASS BASED POWER PROSPECTS IN INDIA In developing countries like India, biomass is an important energy source for power generation (Table 1). By using these surplus agricultural residues, more than 16,000 MW of grid quality power can be generated with presently available technologies. In addition, about 5000 MW of power can be produced, if all the 550 sugar mills in the country switch over to modern techniques of co- generation. Thus, the estimated biomass power potential is about 21,000 MW. For the last 15 years, biomass power has become an industry attracting annual investment of over Rs.1000 crores, generating more than 9 billion units of electricity per year and creating employment opportunities in rural areas. Megawatt scale electricity generation through combustion and cogeneration routes are employed under the Biomass Power/Cogeneration Programme. The Government of India has introduced a host of measures to create awareness amongst stakeholders, demonstrate commercial viability and attract investments in this sector. This has resulted in significant capacity addition of biomass and bagasse cogeneration projects in sugar mills through private sector. Table 2 presents the different conversion technologies alongwith their primary product and applications. Table 3 presents the cumulative achievements under distributed renewable energy power as on 30.09.2006. Table 4 presents proposal for 11th Plan for Grid-interactive Renewable Power. Conservative estimates indicate than even with the present utilization pattern of these residues, and by using only the surplus biomass material, more than 17,000 MW of power could be generated and saved. 34 Compaction of Biomass Compaction of biomass is an important operation to reduce space for storage and increase thermal efficiency. Briquettes of agro- and forest-waste can provide renewable source of energy without addition of any binder. Briquettes have high specific density (1200kg/m3) and bulk density (800kg/m3) compared to 60–180 kg/m3 of loose biomass. It has high thermal value and low ash content compared to coal [5]. Surplus Biomass Available in the Country A lot of surplus biomass is available in different parts of the country (Table 5). The pine tree needles which cause forest fires in the Himachal Pradesh can be utilized directly as a fuel, briquetting or for gasification. This can lead to saving of immense forest wealth from fires [5]. Haryana being an agricultural state has a huge potential of biomass availability in the form of crop residue and saw dust. In the agricultural sector, a total 24.697 Mt y-1 of the residue is generated, of which 71 % is consumed in various domestic and commercial activities within the state. In agro based industrial sector a total of 646 kty-1 of sawdust is generated out of which only 6.65% is consumed in the state. Of the total generated biomass in the state, 45.51% is calculated as basic surplus, 37. 48% as productive surplus and 34.10% as net surplus. The power generation potential from all these three categories of surplus biomass is 1.499 GW, 1.227 GW and 1.120 GW respectively [7]. Madhya Pradesh Urja Vikas Nigam (MPUVN) Limited, Bhopal has carried out a number of biomass assessment studies in selected areas of Madhya Pradesh which reveals that there is a potential of generating at least 200 MW of power using rice husk, mustard crop residue, soy husk, ground nut shell, bagasse and cotton stalk among others. Further, MPUVN has identified certain locations in the various potential tehsils of the state for suitable installation of the biomass based power generation units [10]. Table 1. Aggregate Biomass Generation In India [2] Estimate of the quantity generated, in MT Agriculture/ agro- industrial, 439.43 excluding sugarcane derived materials Source of biomass Sugarcane based materials including tops and trash 84.01 Roadside growths 10.74 Forest residues 157.18 Growths on wastelands 27.12 Agro forestry waste 9.06 Dung live stock 267.76 Poultry droppings 4.86 Total 1000.17

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Journal of Engineering, Science and Management Education Table 2. Thermochemical Conversion Technologies, Primary Products And Applications [4] Technology Primary Products Pyrolysis Fast or Liquid Charcoal Gas flash pyrolysis Liquid tar Solid char Carbonization Slow pyrolysis Liquefaction Liquid Applications Table 3. Cumulative achievements under distributed renewable power as on 30.09.2006 [9] Distributed Renewable Power Liquid fuel substitution, chemicals Solid fuel or slurry fuel Fuel gas Liquid fuel substitution, chemicals Solid fuel or slurry fuel Biomass/ Cogen. (non- bagasse) 11.50 Biomass Gasifier 75.85 Energy recovery from waste 11.03 Total Oil or liquid fuel substitution Gasification Gas Synthesis gas or fuel gas Combustion Heat Heating Table 4. Proposal for 11th Plan for Grid-interactive Renewable Power [9] Programme Component Wind Power Physical Target for Proposed Outlay for th 11th Plan (in MW) 11 Plan (Rs. in crore) 10500 75 (for demo only) Small Hydro Power 1400 700 Biomass Power 1200 600 Co-generation 500 200 Urban Waste to Energy Industrial Waste to Energy Total 200 Installed capacity (MW) 98.3 Table 5. Surplus Biomass As A Percentage of Total Biomass In Different Zones Of The Country [3] S.No. Zone 1. East 75 14000 1800 BIOMASS GASIFIERS BASED DECENTRALIZED / DISTRIBUTED POWER PROJECTS Biomass gasifier based power plants using locally available biomass resources for distributed / stand-alone applications are economically viable option for rural areas. The Ministry of New and Renewable Energy provides support to set up distributed / stand-alone megawatt level biomass gasifier based grid connected power plants following a cluster approach particularly in those states which have biomass potential. Major beneficiaries include individual households and village community. In addition, cottage industries, smallscale industries, public utilities, etc. are also availing benefits from distributed power generated through biomass gasifiers. Table 6. shows the biomass and bagasse based power plants in India supported by MNRE during the year 2006- 2009. Hiremath et. al (2010) used goal-programming method in order to analyze the Decentralized Energy Planning (DEP) through bottom-up approach. This approach included planning from the lowest scale of Tumkur district in India. The scale of analysis included village level—Ungra, The Modal Value Of Surplus Biomass As A Percentage Of Total Biomass West Bengal, Orissa, Bihar (total of 15 talukas) 18-25 % 2. North Harayana, Punjab, Western U. P. (total of 18 talukas) 30-50 % 3. South Andhra Pradesh, Kerala, Tamil Nadu (total of 16 talukas) 20- 35 % 4. West Maharashtra, Gujarat 30- 45 % 150 200 States and Number of Talukas Covered panchayat level (local council) — Yedavani, block level—Kunigaland, district level—Tumkur. The approach adopted was bottom-up (village to district) to allow a detailed description of energy services and the resulting demand for energy forms and supply technologies. Different scenarios are considered at four decentralized scales for the year 2005 and are developed and analyzed for the year 2020. Decentralized bioenergy system for producing biogas and electricity, using local biomass resources, are shown to promote development compared to other renewables. This is because, apart from meeting energy needs, multiple goals could be achieved such as self-reliance, local employment, and land reclamation apart from CO2 emission reduction. They concluded that the biomass feedstock produced from plantations can meet all the electricity needs of the village. Thus the village can be selfreliant. The high electricity demand can be met by raising energy plantation with moderate and high productivity rates (6 and 8 t/ha/year) on the available wasteland. Biomass feedstock available from the energy plantation is adequate to provide electricity through the gasification route [6]. 35

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Journal of Engineering, Science and Management Education Table. 6. Biomass And Bagasse Based Power Plants In India Supported By Mnre During The Year 2006- 2009 [1, 8] S.No. 1. 36 Project Biomass energy and cogeneration (non- bagasse) projects, including captive power projects Use of producer gas Status No. of Units Capacity (MW) (a) To supplement power for various processes in paper mills and rice mills in Uttar Pradesh, Punjab. Completed 33 76 (b) To meet the full requirement of power and steam for M/s Vishal Paper Industries situated at Village - Khusropur, Patiala, Punjab. Completed 1 5.4 (c) Electrical applications in various industries. Completed 18 5.24 (d) Biomass gasifier system with 100% producer gas engines for electricity generation in Sanjiban Hospital & Research Centre in Fuleswar, Uluberia, Howrah, West Bengal Completed 1 1.44 (e) Biomass gasifier system coupled with 100% producer gas engines to provide offgrid power to 18 rural villages of West Champaran, Lakhisarai and Samastipur districts in Bihar. Completed 20 0.64 (f) For providing employment and power partnership for electricity supply, energy services and job creation in rural areas of district Araria, Bihar. It has been set up by The Decentralized Energy Systems India Pvt. Ltd. (DESI Power), Bihar and balance of systems are provided by Netpro Renewable Energy (India) Pvt. Ltd. Mini Rice Mill (7.5 kW), Aatta Chakki (7.5 kW), Chura Mill (3.5 kW), Battery Charging Station (2.0 kW), Mini Work Shop (10.0 kW), Irrigation Pumps (21.0 kW), Briquetting Machine (8.5 kW) are run with this electricity. Completed 7 50 (g) For the production of electricity by Samta Samriddhi Foundation at village Tamkuha, Dhanaha Block; village Madhubani, Rupahi Blocks; Bhitaha, Distt. West Champaran, Bihar. Project provides power to clusters of 500-700 households in rural areas within a radius of 1.5 kms at an affordable price for 5-8 hours everyday. Completed 1 0.032 (h) A project was implemented by Orissa Project & Marketing Development Centre (OPMDC), Cuttack and is used to meet the daily requirement of domestic lighting in 150 families, community hall and primary school lighting, street lighting and other entertainment activities of Kandhal village in Cuttack District of Orissa. The power generated is used for many other applications, such as, flour mill, chafe/fodder cutter machines and water pumps. Completed 2 204

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