Properties of rubbery polymers for the recovery of hydrogen sulfide from gasification gases

Polydimethyl siloxane (PDMS) and two polyether-polyamide copolymers (trade name Pebax) were evaluated for their ability to transport and separate gasification gases. Specifically, the permeabilities of hydrogen, carbon monoxide, carbon dioxide, and hydrogen sulfide were evaluated at temperatures up to 200degreesC. The permeabilities of all gases were approximately ten times faster through the PDMS than the Pebax materials. The permeabilities through all materials at all temperatures evaluated were H2S > CO2 > H-2 > CO. As the temperature increased, the permeabilities of all gases increased through the Pebax. Conversely, for PDMS, hydrogen and carbon monoxide permeabilites increased with temperature while those of H2S and CO2 decreased. The H2S/H-2 selectivities ranges from 1.2 (PDMS at 200degreesC) to 10.3 (Pebax 2533 at 35degreesC). The activation energies for permeation of these polymer/penetrant pairs are reported. (C) 2002 Wiley Periodicals, Inc.