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 hydrog en recoveries for PSA processes producing 99.999 + % hydrogen are in the ra nge 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 p rocesses and the enriched hydrogen stream can be recycled as feed gas to th e PSA process after recompression. The net result of this integration betwe en 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-enri ched gas from the PSA waste gas was experimentally evaluated and two differ ent schemes to integrate the membrane with a specific PSA process for hydro gen purification were studied. The performance of the PSA process was simul ated using a software package called SIMPAC. It is demonstrated that the in tegrated process can increase the net hydrogen recovery to 84-85% from a hy drogen recovery value of 77-78% by the base PSA process. (C) 1999 Published by Elsevier Science B.V. All rights reserved.