Aqueous phase reforming of biofeeds in a membrane microreactor

In this study aqueous phase reforming (APR) of biocarbohydrates is conducted in a catalytically stable washcoated microreactor where multiphase hydrogen removal enhances hydrogen efficiency. APR experiments were performed in a capillary microchannel with a thin washcoated catalyst layer on the wall, containing Pt as active component. During aqueous phase reforming of ethylene glycol and sorbitol, the catalyst layer showed a highly stable performance. Kinetic experiments showed that the hydrogen produced has a negative effect on the reaction. Firstly, a negative reaction order in hydrogen on the aqueous phase reforming reaction was observed. Secondly, hydrogen was being consumed in a competing hydrogenation of the feed components, producing alkanes and alcohols. In comparing the performance of the coated capillary microreactor with a conventional packed bed, the microchannel presented both a higher conversion and selectivity to hydrogen than the fixed bed reactor, which could be attributed to improved mass transfer characteristics. Hydrogen removal by means of stripping with nitrogen proved to be highly beneficial for both the conversion and the selectivity towards hydrogen. Currently experiments are ongoing in which hydrogen is removed by means of a membrane rather than by a more expensive and complex stripping process. In this paper we will be presenting a kinetic study on the effect of hydrogen on APR, as well as experiments in which the effect of hydrogen removal is demonstrated in both a membrane reactor as well as in a microreactor by means of stripping with an inert gas. These experiments will be supported by modeling using the kinetics.