Hydrogen production from partial oxidation of methane in a membrane reactor

Partial oxidation of methane was performed in a packed-bed reactor (PBR), packed-bed membrane reactor with a porous membrane distributor (PBMR#1), packed-bed membrane reactor with a Pd membrane separator (PBMR#2) and a dual membrane reactor equipped with membrane distributor and separator (DMR). Product with H2/CO = 6 was obtained from the PBR operating within flammable region with a feed mixture of CH4/O2 = 1. Safer operation was obtained using the PBMR#1 by partitioning and adding the oxygen reactant through the membrane distributor. Continuous and selective permeation of H2 by Pd membrane in the PBMR#2 allow the production of 97% pure H2 stream, while simultaneously suppressing CO production. Carbon monoxide was absent in both the retentate and permeate streams of the PBMR#2. However, the Pd membrane in the PBMR#2 suffered from severe coking leading to membrane failure. The DMR showed that partitioning oxygen through the membrane distributor could ameliorate coking on the Pd membrane and improve hydrogen selectivity (i.e., PBR = 45%, PBMR#1 = 60%, PBMR#2 = 60% and DMR = 75%). A 100-h monitoring showed that a stable hydrogen permeance rate and purity could be obtained from the DMR.