Wellinger and Lindberg [9] described two basic systems of gas scrubbing with
membranes: a high pressure gas separation with gas phases on the both sides of the
membrane and a low pressure gas liquid absorption on separation where a liquid absorbs
the molecule diffusing through the membrane. The high pressure gas separation
membranes can last up to 3 years which is comparable to the life time of membranes
used for natural gas purification—which last typically 2–5 years.
Rautenbach et al. [16] designed a pilot plant for the removal of CO2 from biogas using
membrane separation technique. He reported that monsanto and acetate cellulose
membranes are more permeable to CO2, O2 and H2S than CH4. The best separation
occurred at 25 8C temperature and 5.50 bar pressure.