Fuel processor for hydrogen production via methanol steam reforming over copper-based catalysts

Abstract

The purpose of this work is to produce high purity hydrogen stream from methanol by an integration of steam reformer and preferential oxidation of CO unit. For methanol steam reformer (MSR), Catalytic activities of Ce-Mg promoted Cu/Al₂O₃ catalysts was investigated in terms of the methanol conversion level, carbon monoxide (CO) selectivity and hydrogen (H₂) yield. It was found that the Ce-Mg bi-promoter catalysts gave a higher performance due to magnesium penetration into the cerium structure causing oxygen vacancy defects on the ceria. A face-centered central composite design response surface model was then designed to optimize the condition at a 95% confidence interval revealed an optimal copper level of 46–50 wt%, Mg/(Ce+Mg) of 16.2–18.0%, temperature of 245–250 °C and S/C ratio of 1.74–1.80. In case of preferential oxidation of CO unit, catalytic activities of copper based catalysts over a series of modified ceria support was investigated in terms of the CO conversion level and carbon dioxide (CO₂) selectivity. The results revealed that the Ce-Mg support gave a higher performance due to magnesium promoted water-gas shift reaction and improved nanorods arrangement. Box-Behnken design response surface model was then designed to optimize the condition at a 95% confidence interval revealed an optimal CO level of 0.65-0.75%, O₂ level of 0.80-0.90% and temperature of 130–140 °C. When integrating both MSR and PROX unit, high purity hydrogen was yielded around 45-47% without CO detected at a rate of ~120 L d⁻¹ g.cat⁻¹.