Development of a Combined Catalyst and Sorbent for Hydrogen Production
Karl O. Albrecht, Justinus A. Satrio, Brent H. Shanks, and Thomas D. Wheelock. Department of Chemical and Biological Engineering, Iowa State University, 2114 Sweeney Hall, Ames, IA 50014
The primary industrial process for the production of hydrogen converts methane via steam reforming (SMR) followed by the water-gas shift (WGS) reaction and a separation stage that removes the CO2 produced as a byproduct. Past studies have shown the advantage of introducing a solid sorbent for the selective, in situ removal of CO2 within the reaction system. This in situ removal of CO2 overcomes the thermodynamic barrier and allows the endothermic SMR and exothermic WGS reactions to be performed simultaneously in the same reactor over a Ni catalyst. A unique approach to this enhanced reaction/sorption process is the use of a combined catalyst and sorbent material. This material consists of a spherical pellet with a sorbent core for the selective removal of CO2 coupled with an outer shell, which acts both as a support for the Ni catalyst and as a strong, protective material for the friable and mechanically weak core. The viability of the core-in-shell concept has been demonstrated previously but improvements in the materials were required. Discussed will be work on enhancing the absorption capacity and cyclic stability of the core over multiple absorption and desorption cycles. Results will also be presented which show how the mechanical strength of the shell can be enhanced while maintaining a high surface area to assure good catalytic activity.