Development of a novel compact reformer for PEMFC.

摘要

A compact reformer to produce hydrogen for portable fuel cell applications is presented in this thesis. This reformer is a conventional single-path tubular reactor type that is packed with granular catalyst particles. The catalyst is used to induce catalytic partial oxidation reaction (CPOX) and steam reforming reaction (SR) in series using a mixture of methanol, water and oxygen as the feed. One of the important features of the reformer is the interlaced flow path for efficient heat transfer between the reactor sections where the endothermic SR reaction and the exothermic CPOX reaction may be taking place, respectively. Flow simulation has been conducted to determine various design features including the dimension of the reformer that can be used for a PEMFC with the energy production capacity of 10 Watt at 50% efficiency. Subsequently, a prototype reformer has been built to confirm the simulation results and to assess the efficacies of new design features.;Experiment with a commercial catalyst (CuO/ZnO/Al2O3 ) showed a methanol conversion of about 85% at the feed rate enough to generate energy production capacity of 10 Watt at 50% efficiency with an operating temperature of 250°C or below, and a hydrogen concentration of approximately 72--73% in the product gas when SR is the only hydrogen generation reaction. When oxygen is fed to the reformer as an additional reactant, CPOX reaction also takes place and the hydrogen concentration decreases slightly as a result. The current study showed a hydrogen concentration of approximately 67%--72% at 250ºC at various oxygen feed rates. These hydrogen concentrations in the product gas are in reasonable agreement with theoretical predictions and indicate that the CPOX reaction does indeed take place before the SR reaction. The experiments indicated that only 5 of the maximum 19 reformer channels filled with catalyst are not sufficient to complete both the CPOX and SR reactions under the conditions used in this study.;The experimental results support that the prototype reformer is capable of meeting the preset requirements to produce enough hydrogen for 10W PEMFC application. The results also suggest that proper insulation of the reformer is essential for self-sustainability.