Optimization of methanol steam reforming over a Au/CuO–CeO2 catalyst by statistically designed experiments

Abstract

The catalytic performance for steam reforming of methanol over 5wt.% Au/CuO–CeO2 catalysts prepared by deposition–precipitation was investigated using a statistical set of experiments in order to optimize the methanol conversion with minimal carbon monoxide (CO) selectivity. The operating temperature, steam to methanol (S/M) ratio, liquid feed rate and the catalyst weight to He flow rate (W/F) ratio, were evaluated with a full 24 factorial design experimental matrix with four central points. The liquid feed rate displayed a much greater influence on the response, masking the importance of the other factors. At a fixed low liquid feed rate, only the operating temperature had a significant influence on the methanol conversion, whilst this plus the S/M ratio and their interaction influenced the CO selectivity. A central composite rotatable design was then used to approximate the optimal conditions by simultaneously considering the methanol conversion and CO selectivity. The optimum theoretical conditions were found to lie within an operating temperature of ~295°C to ~307°C and an S/M ratio of ~1.82 to 2.00 (at a liquid feed rate of 1cm3h−1 and a W/F ratio of 0.17gscm−3), in close agreement with the experimental results.