Bioconversion of different wastes for ENERGY options

Transcription

1 Bioconversion of different wastes for ENERGY options Himali Mehta Principal Scientist Sardar Patel Renewable Energy Research Institute Vallabh Vidyanagar

2 Indian Energy Scenario Coal dominates the energy mix in India - 55% of the total primary energy production Oil - 36 % of total energy consumption India - one of the top ten oil-guzzling nations in the world and will soon overtake Korea as the third largest consumer of oil in Asia after China and Japan Natural gas per cent of energy consumption in the country Nuclear Power per cent of electricity generated Hydropower - steadily decreased and it presently stands at 25% of total power generated

3 Sector-wise Energy Consumption in India

4 India s Reserves, MToE Resource Reserve Production in Extractable coal Extractable lignite R:P Oil Gas Source: Respective ministries

5 The basic aim of energy security for a nation is to reduce its dependence on the imported energy sources for its economic growth. Year-wise Increase in Oil Import Year Quantity (MMT) Value (Rs. In Crore) , , , , , , , , ,30,000

6 Hence, in nutshell, the issue is: India has world s 17% population and only 4% of primary energy It is a growing economy and economic growth generates energy demand Present pattern is predominantly fossil fuel based-87% of commercial energy and 64% of total Fossil fuel reserves are limited

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8 Traditionally, biomass meant wood and other woody materials which were combusted as a direct source of heat an energy form. Commercially also it was an important energy source till the development of coal based economy towards the end of eighteenth century. Even today, traditional biomass accounts for 7% of global energy demand. Primary sources of biomass could be agricultural crops, wood or aquatic biomass where as secondary sources could be crop residues and organic wastes from households, agricultural operations and industries.

9 There are a variety of conversion technologies for conversion of biomass to various forms of energy power, heat and fuels for potential usages in different sectors. Biomass conversion routes for bioenergy

10 The definition of biomass extends well beyond wood and woody type of material. There is another category of organic matter which is high in moisture and low in lignin. Leaf and other leafy biomass, animal and human wastes, crop residues, wastes from certain industrial operations and municipal solid waste falls in this group. The potential of these materials could be extracted through microbial conversion pathways of either digestion or fermentation.

11 Fundamentals of Anaerobic Digestion

12 Cattle Dung based Biogas Plants

13 Alternative Feedstocks Banana stems Water hyacinth Eucalyptus leaves Composite agricultural Composite agricultural wastes Kitchen waste

14 Utilization of Kitchen Waste through Biomethanation Kitchen Kitchen Waste Disposal Cooking Pollution Biogas Biogas plant Digested slurry Fertilizer

15 Performance of Kitchen Waste Biogas Plant Kitchen waste fed, kg/day 140 Biogas generated, cu. m./day 14 LPG saved, kg/day 7

16 Kitchen waste biogas plant at air force, Agra Capacity: 5 cu m Year of installation: 2001 Kitchen waste biogas plant at Bayer ABS Ltd., Nandesari Capacity: 20 cu m Year of installation: 2000

17 Biogas from Jatropha Deoiled Cake Around 320 litres of biogas with 66% methane can be produced from one kg of jatropha deoiled cake

18 Fruit and Vegetable Waste Towns and cities : 4,000 Waste generation : 50,000 tpd Installed capacity of fruits and vegetables processing industry : 2.1 million tpd

19 Schematic Diagram of Biphasic Biomethanation

20 Biomethanation system (10 T/d) at Jain Irrigation Systems Pvt. Ltd, Jalgaon

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22 Anaerobic filter at Vidya Dairy, Anand

23 Comparative Economics of Aerobic and Anaerobic System Parameter Aerobic system Anaerobic system Quantity of effluent, (l/d) 2,50,000 2,50,000 Influent COD, (mg/l) Effluent COD, (mg/l) Electricity used, (kwh/d) Cost of Rs.5.5/kWh Chemicals used, (kg/d) 35 - Cost of Expected biogas production, (cu m/ d) Electricity equivalent of biogas, (kwh/d) Value of electricity produced, (Rs./ d)

24 Burnt wheat straw (Gujarat)

25 Cotton stalks on fire (Gujarat)

26 Uncontrolled burning of rice straw (Punjab)

27 The smoke screen (Punjab)

28 The charred field (Punjab)

29 Availability of Crop Residues SPRERI considered crop residues, which are burnt at present, as surplus; estimated 70 million tonnes per year; Punjab alone burns about 14 million tonnes of paddy straw during October month each year SPRERI conducted a study and developed a technology package for collection, transportation and storage of 1,000,000 tonnes of straw/yr

30 Crop residue to fuel gas and compost

31 Biomethanation of dry crop residues at thermophilic temperatures and of cattle dung at mesophilic temperatures l/kgts Cummulative biogas production, l/kgts l/kgts 143 l/kgts Thermophilic fermentation (Rice straw) Thermophilic fermentation (S ugarcane trash) Mesophilic fermentation (Cattle dung) 218 l/kgts Incubation period, days

32 Energy & Compost Output of an Anaerobic Plant Converting 1 t rice straw / hr RICE STRAW 1T (DM) / HR BIOGAS > 55 % CH m 3 / HR 77 LOE / HR SEMI-DECOMPOSED SOLID RESIDUE 0.7 T (DM) / HR ENRICHED COMPOST BOILER ENGINE TURBINE 0.63 T (DM) / HR 450 kw ANNUAL OUTPUTS ENERGY GROSS 3,400,000 UNITS NET 2,890,000 UNITS COMPOST 6,350 T (25 % MC)

33 Outputs of Bioconversion of Rice Straw Capacity Biogas (m3) per day per yr Oil equivalent per yr (T) Electrical energy (kwh) per yr Compost (T of d m) per yr 1 T / day x x 10 4 (20 kw) * T / hr 7, x , x 10 6 (500 kw)* 2, T / hr 72, x ,800 3,56 x 10 7 (5 MW)* 28,800 * 24 hr/day operation

34 Extensive research is also underway for converting biomass into various transport fuels such as ethanol and butanol through the process of hydrolysis, saccharification and subsequent fermentation of these sugars. Technology using molasses and maize as substrate has been established though there are only a few pilot installations as the process is not yet economically viable for commercialization. However, throughout the world efforts are on to use various agro-residues as substrate, produce low cost enzymes, develop genetically modified microorganisms to give better yield in order to improve the economics of the whole process.

35 Comparison of Potential of Ethanol and Enriched Biogas Production Rice straw (1 ton) Cellulose/hemicellulose Biogas (275 m3) (600 kg) Methane (151 m 3 ) equivalent to Petrol 125 kg or 168 l) Sugars (300 kg) Alcohol (133 kg or 168 l) Fuel CV (MJ/kg) SG equivalent to Petrol (88 kg or 118 l) Ethanol Sugar Petrol

36 Hydrogen Synthesis A little lesser explored aspect of the digestion process is hydrogen synthesis by suppressing methane production and then power generation through fuel cell route. Certain technological interventions like heat treatment, use of inhibitors, maintenance of low ph etc. are being explored wherein hydrogen formation becomes a preferred pathway for the microorganisms involved thereby curbing methane formation.

37 Direct Extraction of Oils A variety of non-edible oilseeds are available in nature; most widely adopted among them for fuel-oil are jatropha, neem and karanj. These raw oils could be directly used for cooking or in enginegenerator for power production. By dewaxing, degumming and transesterification of these oils, biodiesel could be produced which has diverse application than the raw oil. Apart from the use in engine-generator for power production, biodiesel could also be used as transport fuel.

38 Algae Potential Fuel for Future A certain varieties of aquatic biomass also have a huge potential to develop as energy source for future. Algae, a photosynthetic, aquatic organism having a very high biomass production rate (more than perhaps 100 dry tons/hectare/year) contains varying amount of lipids (2-40% by weight), carbohydrates and proteins. According to an NREL (National Renewable Energy Laboratory) report, based on the photosynthetic efficiency and growth, annual algal oil production could be more than 30,000 litres per hectare. This algal oil could be used to produce biodiesel.

39 Once lipids/oils have been extracted, the left-over cake is primarily composed of carbohydrates and proteins which could be put through anaerobic digestion to produce biogas. Alternatively, carbohydrates could be microbiologically converted into sugars for further fermentation to ethanol. Thus, algae give rise to the interesting possibility of producing both biodiesel and ethanol or biodiesel and biogas.

40 Biogas applications Biogas could be used for: direct thermal applications as transport fuel after purification Power production through an enginegenerator The technologies for these options are well established

41 Future Actions?

42 Thank you for your patient hearing!!