Intrinsic kinetics of steam methane reforming on a thin, nanostructured and adherent Ni coating

The intrinsic kinetics of Steam Methane Reforming (SMR) on a non-conventional nanostructured and strongly adherent Ni coating on a metal substrate was experimentally studied using an integral packed bed reactor. The coating was characterized by means of SEM, N-2 adsorption/desorption, EDX, XRD and TPR. The reactor was designed and the operating conditions selected to guarantee negligible interfacial and intra-particle transport limitations, plug flow, isothermal operation and a sufficiently small pressure drop. Experiments were carried out at temperatures between 450 and 600 degrees C, space times between 0.033 and 0.1 mol/(g(cat).s) and steam-to-carbon ratios of 2.87 to 5.53. Discrimination between potential reaction mechanisms and rate determining steps and estimation of the rate parameters and their confidence intervals followed from regression and statistical and physicochemical testing. Measurements confirmed that the water gas shift reaction reached equilibrium for each condition. A comparison with reported intrinsic kinetics for a conventional SMR catalyst was made and optimal catalyst coating thickness, accounting for intra-catalyst diffusion limitations was evaluated.