Hydrogen production by steam reforming of methanol in a micro-channel reactor coated with Cu/ZnO/ZrO_2/Al_2O_3 catalyst

摘要

Hydrogen production by steam reforming of methanol is studied over Cu/Zn-based catalysts (Cu/ZnO, Cu/ZnO/Al_2O_3, Cu/ZnO/ZrO_2/Al_2O_3). Cu/Zn-based catalysts are derived from hydrotalcite-like precursors prepared by a co-precipitation method. The catalysts are characterized by N_2O chemisorption, XRD, and BET surface area measurements. ZrO_2 added to the Cu/Zn-based catalyst enhances copper dispersion on the catalyst surface. Among the catalysts tested, Cu/ZnO/ZrO_2/Al_2O_3 exhibits the highest methanol conversion and the lowest CO concentration in the outlet gas. A micro-channel reactor coated with a Cu/ZnO/ZrO_2/Al_2O_3 catalyst in the presence of an undercoated Al_2O_3 buffer layer exhibits higher methanol conversion and lower CO concentration in the outlet gas than in the absence of an undercoated Al_2O_3 buffer layer. The micro-channel reactor with a undercoated Al_2O_3 buffer layer produces large amounts of hydrogen compared with one without a buffer layer. The undercoated Al_2O_3 buffer layer enhances the adhesion between catalysts and micro-channel walls, which leads to improvement in reactor performance.