Ensemble process for producing high-purity H2 via simultaneous in situ H2 extraction and CO2 capture

Abstract

To produce fuel-cell-grade hydrogen (H-2) via fossil fuel reforming processes, an efficient H-2 purification method with a carbon capture unit is necessary. In this study, a sorption-enhanced water-gas shift membrane reactor (SE-WGS-MR) system combining a state-of-the-art MgO-based catalyst, carbon dioxide sorbent, and Pd/Ta membrane is developed to simultaneously capture carbon dioxide and purify H-2. With the optimal sorption-enhanced configuration (SEWGS), the carbon monoxide conversion is significantly enhanced to 86.6%, compared with 68.5% using the commercial catalyst only. Coupling of the Pd/Ta membrane with the WGS catalyst (WGS-MR) enable over 95% H-2 recovery, with the production of high-purity H-2. Eventually, the ensemble of the three processes (SE-WGS-MR) afford 99.99% of carbon monoxide conversion and the extraction of high-purity H-2 with 99.5% recovery. This study demonstrates the potential of the single process integrating the catalytic reaction, adsorptive separation, and membrane purification for the production of H-2 with ultra-high purity and recovery.