Gobar Gas (Methane) is generated by the de- composition of organic cow dung. It consists of 55-65% methane, 30-35% carbon dioxide, with some hydrogen, nitrogen and other traces.
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Biogas is a gas whose primary elements are about 65% of methane (CH4) and about 35% of carbon dioxide (CO2). It is a product of the natural decomposition of any organic substance of animal or plant origin due to the activity of anaerobic (functioning in a non-oxygen environment) bacteria. Major sources of methane are all animal excrements, waste landfills, and any other organic material which is left untreated. The most common substrates, used to produce biogas are:
- green cuttings; maize- /grass- and whole-plant silage; corn; hay/ straw; slops; grain tailings; glycerin; pomace; dry poultry droppings; poultry/turkey manure; cattle and pig manure; food waste; floating sludge; rumen/stomach content; slaughter wastes and blood
The bacteria involved in the process are methanogenic bacteria, which are subdivided into psychrophilic, mesophilic and thermophilic strains according to their optimum temperature range. The optimum temperature for mesophilic bacteria lies in the range 38°C – 40°C, while the thermophilic group prefers 50°C – 60°C. The pH value of the fermentation substrate lies between weakly acidic (ca. pH 6) and weakly alkaline (ca. pH 8). Antibiotics, disinfectants and other chemicals present in the substrate can seriously inhibit or even stop completely the fermentation process.
The main product from this fermentation is biogas, an energy source for the generation of renewable energy. The components of biogas – methane and carbon dioxide - act as greenhouse gases that harm the environment if released unburned into the atmosphere. The production of biogas in biogas plants prevents uncontrolled emission of methane into the atmosphere and, by generating renewable energy in the form of biogas, reduces the use of fossil fuel.
What is a biogas plant?
Substrates in the form of organic material such as animal excrements, remnants of food processing, silage from plants, slaughterhouse leftovers and almost any other organic material are ground and fed into large (2.500 to 5.000 cubic metres) hermetically-closed containers known as digesters. In the digesters these substrates are heated to an optimal temperature and agitated so as to produce biogas, which bubbles to the top of the substrate and is collected in a biogas container. This biogas is fed into an electric generator which produces electricity and heat. The whole process is electronically monitored, the remaining substrate can be used as a high quality ecological fertilizer.
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Biogas typically refers to a gas produced by the breakdown of organic matter in the absence of oxygen. It is a renewable energy source. Furthermore, biogas can be produced from regionally available raw materials and recycled waste and is environmentally friendly and CO2 neutral. Biogas is produced by the anaerobic digestion or fermentation of biodegradable materials.Biogas comprises primarily methane and carbon dioxide nd may have small amounts of hydrogen sulphide, moisture and siloxanes. The gases methane, hydrogen, and carbon monoxide can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel. Biogas can be used as a fuel in any country for any heating purpose. It can also be used in anaerobic digesters where it is typically used in a gas engine to convert the energy in the gas into electricity and heat.Biogas can be compressed and used to power motor vehicles. Biogas is a renewable fuel so it qualifies for renewable energy subsidies in some parts of the world. Biogas can also be cleaned and upgraded to natural gas standards when it becomes bio methane.
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