Читать книгу Encyclopedia of Renewable Energy - James Speight G., James G. Speight - Страница 186

All coals contain biogenic gas, but only the higher rank coal (bituminous) contains thermogenic gas. Biogenic methane is formed in coal seams by naturally occurring bacteria that are associated with meteoric water recharge at outcrop or sub-crop. Biogenic methane is a term used to describe natural gas derived from the reduction of carbon dioxide via biogeochemical processes. The processes which contribute to the production are complex, poorly understood, but pervasive in nature and vary from site to site. Biological processes include methanogenesis and hydrogenogenesis, but there are also geochemical processes that have been identified. Methanogenic bacteria generate methane by several pathways, principally the fermentation of acetate and the reduction of carbon dioxide. In coal seams, methanogens may increase coalbed methane production.

See also: Biogas.