Hydrogen production by hybrid SMR-PSA-SSF membrane system

Pressure swing adsorption (PSA) processes are commonly used to produce pure hydrogen from the steam-methane reformer (SMR) off-gas. The typical hydrogen recoveries for PSA processes producing 99.999 + % hydrogen are in the range 70-85%. The nanoporous selective surface flow (SSF) carbon membrane can be used to extract hydrogen from the low pressure waste gases of the PSA processes and the enriched hydrogen stream can be recycled as feed gas to the PSA process after recompression. The net result of this integration between the PSA process and the SSF membrane is increased hydrogen recovery from the SMR off-gas. The separation performance of the SSF membrane in producing a hydrogen-enriched gas from the PSA waste gas was experimentally evaluated and two different schemes to integrate the membrane with a specific PSA process for hydrogen purification were studied. The performance of the PSA process was simulated using a software package called SIMPAC. It is demonstrated that the integrated process can increase the net hydrogen recovery to 84-85% from a hydrogen recovery value of 77-78% by the base PSA process. (C) 1999 Published by Elsevier Science B.V. All rights reserved.