Selective Removal of H 2 S from Gas Streams with High CO 2 Concentration Using Hollow‐Fiber Membrane Contractors

Selective and simultaneous separation of H 2 S and CO 2 from CH 4 was accomplished in a hollow‐fiber membrane contactor (HFMC). The absorption of both H 2 S and CO 2 using an aqueous solution of methyldiethanolamine (MDEA) was almost complete and acid gases were totally removed. Despite the large difference between H 2 S and CO 2 concentrations, the rate of H 2 S absorption was not significantly influenced by CO 2 absorption. The independent effect and interactions of several process variables on the separation performance of H 2 S and CO 2 were investigated. The results indicated that the membrane contactor could be a highly efficient choice for removal of almost all H 2 S in the presence of a large CO 2 content even at high gas/liquid flow ratio. The selectivity of H 2 S was about three times higher compared to the conventional absorption packed towers.