H2S Removal from Biogas Using an Ionic Liquid as Physical Absorbent

Biogas is nowadays a valuable renewable energy carrier which can be used directly as a fuel or as a raw material for the production of synthesis gas and/or hydrogen. Methane (CH₄) and carbon dioxide (CO₂) are the main constituents, but biogases also contain significant quantities of undesirable compounds (contaminants), such as hydrogen sulfide (H₂S) and ammonia (NH₃). The existence and quantities of these contaminants depend on the biogas source (i.e., landfills, anaerobic fermentation of manure). Their presence constitutes a major problem because (1) they can adversaly affect any biogas thermal or thermocatalytic conversion device (e.g., corrosion, erosion, fouling); and (2) they produce harmful environmental emissions. It is therefore important to develop a reliable and efficient biogas purification process. This work is aimed at presenting an alternative removal approach for H₂S from biogas based on physical absorption using an ionic liquid as solvent.