Pressure swing adsorption (PSA), also known as carbon molecular sieves, is the second most commonly used biogas upgrading technology in Europe.
The upgrading takes place over 4 phases: pressure build-up, adsorption, depressurization and regeneration. The pressure buildup is achieved by equilibrating pressure with a vessel that is at depressurization stage. Final pressure build up occurs by injecting raw biogas. During adsorption, CO2 and/or N2 and/or O2 are adsorbed by the media and the gas exits as CH4.
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