Membranes – The Answer to Biogas Clean-Up

A micro-porous hollow-fibre membrane gas absorber has been applied for the removal of H2S and other impurities from biogas streams, generated at landfill sites and anaerobic digestion plants. Various methods are available for biogas clean-up, including water/chemical wall, chemical absorption, adsorption and cryogenics. These treatment processes face problems such as pollution, disposal/treatment costs, partial effectiveness, wetting of gas, use of expensive chemicals, high OPEX and CAPEX cost. HF membrane gas absorption overcomes these problems and achieves controllable removal at lower operating cost. All studies were conducted within single passage through the membrane at pH range 7 to 13. Non-wetted mode of operation was considered. A mathematical model describing the process of absorption of the contaminants present in biogas stream from LF and AD plants was developed. The experimental observations and model predictions were in good agreement with less than 1% error. Removal efficiencies of H2S up to 99.9%, were achieved.