Hydrogen production through aqueous-phase reforming of ethylene glycol in a washcoated microchannel

Aqueous-phase reforming (APR) of biocarbohydrates is conducted in a catalytically stable washcoated microreactor where multiphase hydrogen removal enhances hydrogen efficiency. Single microchannel experiments are conducted following a simplified model based on the microreactor concept. A coating method to deposit a Pt-based catalyst on the microchannel walls is selected and optimized. APR reactivity tests are performed by using ethylene glycol as the model compound. Optimum results are achieved with a static washcoating technique; a highly uniform and well adhered 5 μm layer is deposited on the walls of a 320 μm internal diameter (ID) microchannel in one single step. During APR of ethylene glycol, the catalyst layer exhibits high stability over 10 days after limited initial deactivation. The microchannel presents higher conversion and selectivity to hydrogen than a fixed-bed reactor. The benefits of using a microreactor for APR can be further enhanced by utilizing increased Pt loadings, higher reaction temperatures, and larger carbohydrates (e.g., glucose). The use of microtechnology for aqueous-phase reforming will allow for a great reduction in the reformer size, thus rendering it promising for distributed hydrogen production. Left out to dry: Aqueous-phase reforming (APR) of biocarbohydrates is conducted for the first time in a catalytically stable washcoated microchannel in which multiphase hydrogen removal enhances the hydrogen efficiency. The microchannel presents higher conversion of ethylene glycol and higher selectivity to hydrogen than a fixed-bed reactor. The use of microreactor technology for APR allows for a great reduction in the reformer size, which is promising for distributed hydrogen production.