By, N Venkata Srinath, 1 st Year MS Power Systems.

Bio-Gas Biogas typically refers to a gas produced by the biological breakdown of organic matter in the absence of oxygen. This is produced by anaerobic decomposition of bio- mass.

How Bio-gas is alternative/renewable The increased consumption of energy all over the world has led to a drastic increase to the rates of all carbon based fuels. A finite(Non renewable) sources that will not be able to meet the increasing fuel needs in the world. Fossil fuels emitting excessive carbon dioxide and other gases, they increase the global warming in the world……….

One of the alternative as well as renewable source of energy is Bio-Gas.

Evaluation 1630-Von Helmont first observed about an inflammable gas emanating from decaying organic matter. But, major exposure was from the World War II when people faced scarcity of fossil fuel.

Block diagram of Bio-gas Production Input Digester Methane(40-70)% Slurry CO2 (30-60), H2- 1 %, N2 -0.5%, CO- 1 %, O2- 1 %, H2S- 1 %

Input Bio-Mass Animal-wasteAgro-waste Night soil Dung Crop Residue Slaughterhouse Vegetable Waste Poultry-Casting Catering Waste Dead Bodies Food processing Waste

The above inputs either sole or in combination are mixed with water and fed into a digester. Digester: A biogas digester, also known as a methane digester, is an equipment which can turn organic waste into usable fuel. The biogas digester relies on bacterial decomposition of biomass.

Digester Types Fixed-dome plants Floating-drum plants Balloon plants Horizontal plants Earth-pit plants Ferro cement plants

Fixed-dome plants

Characteristics The costs of a fixed-dome biogas plant are relatively low. It is simple as no moving parts exist. Here are also no rusting steel parts and hence a long life of the plant (20 years or more) can be expected. The plant is constructed underground, protecting it from physical damage and saving space. There wont be much external temperature effect.

Floating-drum plants A floating-drum plant consists of a cylindrical or dome-shaped digester and a moving, floating gas-holder, or drum If biogas is produced, the drum moves up, if gas is consumed, the gas-holder sinks back.

Digestion Process Bio-Chemical process. Anaerobic decomposition.

Digestion Process Bio-Chemical process: Here, micro organisms are involved in the chemical reaction.

Digestion Process Bio-Chemical process: Here, micro organisms are involved in the chemical reaction. Anaerobic decomposition: A process in which organic matter is broke down into simple compounds in the absence of oxygen. Anaerobic decomposition AcidificationMethanogenesis

Acidification: In this, acidic bacteria dismantle the complex organic molecules into peptides, glycerol, alcohol and the simpler sugars. Methanogenesis: In this process, methane producing bacteria gets activated and produce methane gas by utilizing the products obtained from acidification.

Anaerobic digestion will occur best within a pH range of 6.8 to 8.0. and temperature range of C More acidic or basic mixtures will ferment at a lower speed. The introduction of raw material will often lower the pH (make the mixture more acidic). Digestion will stop or slow dramatically until the bacteria have absorbed the acids. A high pH(Basic in nature) will encourage the production of acidic carbon dioxide to neutralize the mixture again.

Output Methane(40-70)% CO 2 (30-60)% O % CO - 1% H 2 S -1% N % By- product: Slurry( N-1.4%,P-1%,K-0.8%.)

Applications Power Generation: Biogas can be used to operate a dual fuel engine and can replace up to 80% of diesel. Biogas can be used for cooking. Gas lamps can be fueled by biogas.

Advantages Eco friendly energy production. Smaller biogas production units can support lightning and cooking. Visible improvement in rural hygiene. Environmental benefits on a global scale: Biogas plants significantly lower the greenhouse effects on the earth's atmosphere. Protects the earth's natural resources. Conversion of natural organic waste into Bio-fertilizer.

Disadvantages The main disadvantage is the loss of the organic waste for compost or fertilizer. Very limited in the quantity of electricity it can produce on the global scale. There is little or no control on the rate of gas production, although the gas can, to some extent be stored and used as required.

Technical Details Size of plant Quantity of cattle dung required daily No. of cattle heads required Estimated cost 1 cubic meters25 kg2-3Rs.7,000/- 2 cubic meters*50 kg4-6Rs.9,000/- 3 cubic meters75 kg7-9Rs.10,500/- 4 cubic meters100 kg10-12Rs.12,500/- 6 cubic meters150 kg14-16Rs. 15,000/- * A biogas plant of 2 cum capacity is sufficient for providing cooking fuel to a family of 4 members.

Indian Scenario In India its experimentation started in The importance of energy was brought into sharp focus since the 1970’s oil shortage which escalated the prices of conventional energy. Since then attention has shifted to alternative sources of energy. The Central Sector Scheme on National Biogas Program, which mainly caters to setting up of family type biogas plants, has been under implementation since

The Municipal Corporation of Delhi is planning to install a 1-MW bio-gas power plant on a public-private partnership basis at the Ghogha Dairy complex in North Delhi Central Subsidy : Capacity of the Biogas plant (Cum) General (Rs.) SC/ST/Small farmers (Rs.) Additional for attaching toilet (Rs.) to