SCALE-UP OF SELECTIVE SURFACE FLOW MEMBRANE FOR GAS SEPARATION

The Selective Surface Flow (SSF) membrane, consisting of a nanoporous carbon layer supported on a macroporous alumina tube, can be used to e nrich hydrogen from a feed gas containing hydrogen and hydrocarbon mix tures. The membrane produces a hydrogen-enriched product stream at fee d gas pressure by selectively rejecting the hydrocarbons to the low pr essure side of the membrane. Bench-scale testing of the membrane showe d that very high rejections of C-2(+) hydrocarbons can be achieved fro m a feed gas containing low concentrations of hydrogen at moderate pre ssure. The membrane has been scaled-up in length and field-tested in m odular form using a real refinery waste gas under actual operating con ditions. It successfully tracked the performance of the bench-scale un it under field conditions. Both bench-scale and field-scale performanc e data are described. Six months of continuous operation in the field did not exhibit any degradation of membrane performance.