A novel study of sulfur-resistance for CO2 separation through asymmetric ceramic-carbonate dual-phase membrane at high temperature

Abstract

Sulfur compounds present in high-temperature gases from various industrial sources have a negative influence on the permeability of different kinds of membranes. In this study, we present a general and efficient strategy to design and prepare two asymmetric membranes for CO2 separation that are resistant to H2S. The asymmetric membranes, mainly composed of one adsorbed layer for H2S consumption and one dense ceramic-carbonate layer for CO2 separation, show not only high CO2 permeation flux but also remarkably stable permeation behavior under an H2S-containing atmosphere. The sulfur-resistant stability times of the asymmetric membranes are approximately 10–12 times higher than the single ceramic-carbonate dual-phase membrane. The adsorbed layer of the asymmetric membranes can react with H2S to form Ce-O-S phases, gradually causing deactivation of the adsorbed layer. However, the adsorbed layer can be regenerated in the oxygen-containing gas stream above 850 °C, which can effectively remove the sulfur content from the adsorbed layer, making recycle of the membrane possible. Sulfur accumulated in the adsorbed layer of the membrane as a Ce2O2S phase, can be oxidized into SO2 under air stream and elemental sulfur (S) under a 2.5% O2/He gas stream. These asymmetric membranes thus possess high permeation stability in the H2S-containing atmosphere with good regenerability and also have potential in collection and removal of sulfur impurities from gas streams.