Progress on the Selective Removal of H2S from Gasified Coal Using an Immobilized Liquid Membrane

A recent development in selective removal utilized aqueous carbonate solutions in the form of an immobilized liquid bicarbonate/carbonate ion membrane through which facilitated hydrogen sulfide transport took place. The relatively high permeability of the membrane to hydrogen sulfide at 90/sup 0/ to 130/sup 0/C and at 300 atm total feed-gas pressure appears promising for industrial application under similar operating conditions. In the study, a 30% potassium carbonate solution is immobilized by impregnating it in a microporous hydrophilic polymer membrane, and gas gaps are formed by interposing microporous Teflon pads between successive membranes. The immobilized membrane scrubbing system provides a selectivity for hydrogen sulfide/carbon dioxide mixtures that is superior to that of conventional hot carbonate scrubbers.