Production of biogas refers to the process where the gas is produced by anaerobic digestion or fermentation of organic manure and biodegradable wastes. This type of natural gas helps the humans in the production of electricity.
Some of the processes patented are given below.
Patent no: 7,101,481 titled ‘System for the production of biogas and compost from organic materials and method of operating an organic treatment facility’ with the abstract: A system and method for continuous decomposition of organic material to produce biogas and compost in which successive reactor zones in a primary reactor are used in turn to receive organic material which is decomposed in situ anaerobically followed by aerobic decomposition and excavation of raw compost from the same reactor zone where it is received into the organic treatment facility. Organic rich liquor recovered during anaerobic decomposition is further decomposed in a secondary reactor from which spent liquor is returned to the primary reactor while biogas harnessed from both the primary and secondary reactors is treated, and optionally used to fuel the operation of the organic treatment facility or for sale as fuel or electricity.
Patent no: 6,454,944 titled ‘Process and apparatus for conversion of biodegradable organic materials into product gas’ with the abstract: A method and apparatus for efficiently generating biogas from feedstocks composed of 10 to 100 percent biodegradable solids including carbohydrates, starches and/or sugars, for a variety of uses including the creation of electricity. The apparatus includes a thermophilic digester and a mesophilic digester used in series, in communication with a feedstock supply system. The digesters may be established as a stand-alone system or made part of a wastewater treatment facility. By carefully metering the specialized feedstocks into and between the digesters, maximum production of biogas can be achieved. The biogas may then be burned as part of an electricity generating process, or stored for later use.
Patent no: 5,315,938 titled ‘Heat accumulator’ with the abstract: Liquid accumulators which substantially include several or at least one type of energy generation, such as heatable to almost the temperature of fresh air by solar irradiation with the thermal supply of circulation heat, by refuse combustion with the recovery of waste heat, by recovery of waste heat from exhaust gases in the case of heating boilers and generators, and also usable in a continuous process for the production of biogas from small refuse in the sewage.
Patent no: 4,565,552 titled ‘Method of producing biogas and compost’ with the abstract: In the mesophile production of biogas, the temperature of the liquid used during anaerobic, methanogenic, and fermentation is raised to the required temperature (about 35.degree. C.) by aerobically prefermenting solid substrate at substantially ambient temperature and of appropriate moisture content to raise its temperature to a temperature greater than that required for the anaerobic, methanogenic, fermentation. Thereafter flooding the fermenting solid substrate with the liquid at substantially ambient temperature to increase the temperature of the liquid by heat exchange, and then removing the liquid and storing it in a heat insulated environment to reduce the moisture content of the solid substrate to a suitable degree. The above steps of aerobic prefermenting and flooding are repeated until the liquid has reached the required temperature, and then leaving the liquid in situ to enable anaerobic methanogenic fermentation to take place. In so doing the supply of external heat for the initial warming up of the substrate may be dispensed with, thereby improving the efficiency of the method.