Hydrogen from coal using reaction swing approach

An innovative scheme to separate hydrogen from coal gasification products for end users such as clean energy production is presented. The main approach of this process is the use of catalysts (Me) in a fixed bed reactor that will increase hydrogen purity by CO disproportionation that yields in elemental carbon and carbon dioxide. The resulting carbon dioxide immediately reacts with specially modified calcium based component that acts as a carbon dioxide removal material (CDRM), thus producing carbon-based-gases-free hydrogen. The reverse flow of air is used to regenerate the carbon-loaded catalyst and the heat liberated via the exothermic reaction is utilized to regenerate carbon dioxide capture agent releasing carbon dioxide. Thus, the product of this system would result into hydrogen ready for use in fuel cells. Figure 1 shows the schematic of the process. Pure hydrogen stream was produced from different syngas mixtures. The effect of the process parameters such as temperature, steam content, syngas composition, syngas content in the feed stream, residence time etc., on conversion efficiency are presented. The response variables used for determining the optimal catalyst preparation conditions were the reactivity and extent with respect to CO disproportionation, hydrogen purity, catalyst deactivation, and will be related to the porosity, pore radii, dispersion on the support, and particle size. Experiments were also conducted to evaluate the effect of solids composition on the product gases. In the absence of any steam, some degree of methane formation was observed when the gas flow rate was high/short contact time. No significant loss in hydrogen yield was observed even when no steam was added.