Hydrogen production using sorption-enhanced reaction

This study examined the sorption-enhanced production of H-2 via the steam-methane reforming process using a mixture of Ni-based commercial reforming catalyst and Ca-based sorbent obtained from commercial dolomite. The rates of the reforming, water-gas shift, and CO2 removal reactions are sufficiently fast that combined reaction equilibrium was closely approached, allowing for > 95 mol% H-2 (dry basis) to be produced in a single step. A dolomite pretreatment procedure was developed to remove sulfur, which was necessary to avoid poisoning of the reforming catalyst. The multicycle durability of the catalyst-sorbent mixture was studied as a function of regeneration temperature and gas composition using a laboratory-scale fixed-bed reactor. Twenty-five-cycle tests showed only moderate activity loss under most of the regeneration conditions studied. The primary loss in activity was associated with the inexpensive sorbent instead of the more expensive catalyst.