Hydrogen Separation from Syngas Utilizing Inconel as a Boudouard Catalyst
A process for separating hydrogen from syngas for use as a carbon-less energy carrier is reported. The overall process consists of a hydrogen separation step and a solids regeneration step in a lab-scale, fixed-bed reactor under atmospheric pressure. During the enrichment step, syngas and steam were passed through a bed of Inconel, which catalyzed the Boudouard reaction. The newly formed gaseous mixture of H2O, CO, CO2, and H2 continued through the reactor, while the deposited carbon remained at the Inconel bed or contributed to the water gas reaction. The produced gases then passed through a calcium oxide bed where the water gas shift and carbonation of CaO reactions occurred simultaneously to yield a stream of hydrogen. When the solids were spent, the syngas and steam feeds were then replaced by air to regenerate the solids, which released sequestration-ready carbon dioxide. The effects of moderate temperatures, steam concentrations, residence times, and solids ratio on hydrogen purity were studied. The information obtained was used to optimize of the process and achieve a 99 % hydrogen stream. Multiple cycles using the same solids were completed with a minimal loss in performance observed.