Medium Temperature Shift Reaction Over Copper-Ceria catalyst in Fixed-Bed and Microchannel Reactors

One of the effective catalysts for the hydrogen purification and production via medium temperature shift reaction, is Cu-Ce solid solution. Cu0.1Ce0,9O1.9 was produced using the co-precipitation method and then was utilized as support for the 5Cu/Ce0.9Cu0.1O1.9 catalyst which was synthesized employing the wet impregnation method. The X-ray diffraction (XRD) analysis showed that the crystalline sizes of Ce0.9Cu0.1O1.9 and 5Cu/Cu0.1Ce0,9O1.9 were 9.22 and 18.33 nm respectively. The Catalysts were evaluated in medium temperature shift reaction at 300-390 °C and at the gas hourly space velocities (GHSV) of 12000 and 30000 h^-1, in a fixed bed reactor. Due to the higher concentration of Cu and the positive synergic effects of both the active metal and support, the 5Cu/Cu0.1Ce0,9O1.9 catalyst showed a better performance. It was also concluded that, because of the short residence time at high levels of GHSV, increasing GHSV would lead to a decrease in the CO conversion. Then 5Cu/Cu0.1Ce0,9O1.9 was evaluated in a microchennel reactor in 2 GHSVs of 12000 and 30000 h^-1 and results were compared with thoes of the fixed-bed reactor. It can be concluded that the microchannel reactor is better in higher GHSVs (shorter residence time of the gas flow). A microchannel reactor provides a high surface-to-volume ratio and gases pass over the thin layer of catalysts on the coated plates. Hence, due to the better access to the catalytic bed, the reactants react even in a short time, which improves the performance of the microchannel compared to that of the fixed bed reactor.