Evaluation of chemical aspect of biogas upgradation (CBG production) techniques & their environmental impact
Biogas is a renewable source of energy derived from anaerobic digestion of biomass which mainly comprises of dairy waste widely available in form of cattle dung in the Indian villages. Its main constituent comprises of methane, carbon dioxide, hydrogensulphide with trace of nitrogen, water vapour, hydrogen, oxygen, organic silicon compounds and ammonia, however, their composition varies with the source. In modern world compressed biogas is the fuel of choice and necessity, not only in India but for the world. Biogas upgrading is a gas separation task, finally yielding a methane-rich product. In order to obtain methane rich gas, the biogas must pass through two processes, a cleaning process & an upgrading process. In the later calorific value and other parameters are adjusted to meet the specifications of it as fuel by the removal of carbon dioxide, sulphur & moisture etc. This upgraded gas can be compressed to CBG, which is a good alternative to CNG and can be used as vehicle fuel and for running power plants and also it has other important uses in different industries. The upgrading systems used could be organic physical scrubbing, water scrubbing, amine scrubbing, pressure swing adsorption, membrane separation, water scrubber, cryogenic separation and liquefaction. The suitability of technology is decided by various aspects including cost, size and quantity of biogas generation, quality of biogas and process economics. The clean and upgraded biogas can be introduced in to the natural gas grid since it is comprised of mostly CH4. The purified biogas can be bottled in CNG cylinders to obtain CBG and it can be used as an alternative to CNG. The paper intends to summarize the technologies available for biogas upgradation that can be carried out for production of effective compressed biogas. The cost of storing and transporting biomethane along with the assessment of environmental impact of these methods is also reported.
Richa Saxena. Evaluation of chemical aspect of biogas upgradation (CBG production) techniques & their environmental impact. International Journal of Ecology and Environmental Sciences, Volume 2, Issue 3, 2020, Pages 278-285