Use of membranas for biogas purification: review

Abstract

Biogas is a clean organic fuel that is produced by the decomposition of organic matter under anaerobic conditions, composed of about 55-65% methane, 30-45% carbon dioxide, traces of hydrogen sulphide and fractions of water vapour. The presence of compounds other than methane, although occurring at very low concentrations, is a problem since they are detrimental to any processing equipment and restrict their use. Therefore, in order to achieve the standard biogas composition, it is important to include purification steps before using biogas. Traditional technologies for purification are essentially based on the use of physical and chemical methods, which also generate secondary pollutants, and are expensive. The current study is a review of different membrane-based biogas purification processes that are widely used worldwide, and the key technologies being developed or under research. Appropriate membrane materials, as well as an efficient module and process design, determine competitiveness with conventional separation technology.