13-02-2013, 12:45 PM
Bio Gas Report
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Introduction of biogas
The technology for the production of biogas, by anaerobic fermentation of organic materials which are abundant, low-cost and renewable in nature, is readily available. In fact, several thousand biogas plants are already in operation in many developing countries such as India, China, Thailand, Asian countries and others. However, further widespread generation and use of biogas depend largely on the availability of inexpensive and appropriate plant designs, which could be constructed with locally available materials and skills. Also, it is important that financial institutions and national governments consider liberal fiscal incentives to make this technology attractive at the level of individual families as well as communities.
The thesis explains the theory of biogas productions, factors affecting plant designs, and operation of plants. Details of several popular biogas plant designs, their construction, installation, operation and maintenance have been covered with appropriate illustrations. Designs of biogas utilization devices and their operational requirements for used in lighting and cooking and as fuel for prime movers have also been included. Further, the use of digested slurry as a source of organic fertilizer is discussed Technical problems faced in the construction and operation of biogas plants and appliances have been identified along with the causes and known solutions.
What is Bio Gas?
Biogas is gaseous mixture of methane, carbon dioxide, hydrogen sulphides and several other
gases, produced by anaerobic fermentation of organic material such as animal and human
manure, leaves, twigs grasses, industrial waste, etc. The presence of methane in biogas lends it the property of combustion which makes it suitable for cooking, lighting, and powering prime movers.
Mechanism of extraction
The fermentation process for formation of methane from cellulosic material through the agency of a group of organisms belonging to the family „Methanol bacteriaceae is a complex biological and chemical process involving two main stages.
Stage first:
bacteria break down complex organic materials, such as carbohydrates and chain molecules, fruit acid material, protein and fats. The disintegration produces acetic acid, lactic acid, propaonic acid, butanoic acid, methanol, ethanol and butanol, as well as carbon dioxide hydrogen H2S and other non organic materials, in this stage the chief micro-organisms are ones that break down polymers, fats, proteins and fruit acids, and the main action is the butanoic fermentation of polymers.
Stage second: the simple organic materials and carbon dioxides that have been produced are either oxidized or reduced to methane by micro-organisms of which there are many varieties.
Methane Production :
Airtight : Breakdown of organic materials in the presence of oxygen produces co2 and in the absence of it produces methane.
Temperature:
Temperature for fermentation will greatly affect biogas production. Depending upon prevailing conditions methane can be provide within a fairly organisms which take part in methane fermentation have the optimum activity at 35 deg C-40 deg C. The production of biogas is fastest during summer and it decreases at lower temperature during winter. Also methanogenic micro-organism are very sensitive to temperature changes, a sudden change exceeding 30C will affect production, therefore one must ensure relative stability of temperature.