Hydrogen Production Performance of a Self-Heating Methanol Steam Reforming Microreactor

Abstract

The study of microchannel methanol steam reforming plays an important role in improving the efficiency of hydrogen production and promoting the development of clean energy. This thesis numerically simulates a circle-triangle microchannel—a reactor catalyst with a porous media structure—that works with internal methanol combustion for heat supply and external methanol-reforming for hydrogen production. The heat transfer performance inside the microchannel and the chemical reaction kinetic rate of methanol were analyzed; the effects of different conditions such as inlet velocity, water-to-alcohol ratio, and reaction temperature on the hydrogen production performance of the microchannel reactor were analyzed, and the reaction law and transport characteristics inside this microchannel were revealed. The results show that the overall temperature distribution of the microchannel reactor is relatively uniform; the reforming reaction mainly occurs at the outer side of the porous catalytic layer, the internal mass transfer resistance is large, and the reforming reaction needs to optimize the pore structure of the catalytic layer to reduce the mass transfer limitation; the velocity variation in the reforming channel is large, the hydrogen yield increases with the temperature increase, and the water-alcohol ratio and inlet velocity need to be controlled to achieve the best performance. This study focuses on the performance analysis of a microchannel methanol steam reforming reactor aimed at improving hydrogen production efficiency and promoting clean energy. Numerical simulations of the circular-triangular microchannel reactor revealed its heat transfer performance and chemical reaction kinetics. The temperature distribution of the reactor was relatively uniform, and the reforming reaction mainly occurred outside the catalyst layer. At the same time, the internal mass transfer resistance was significant, suggesting that the pore structure of the catalytic layer needed to be improved to enhance the catalyst utilization. Meanwhile, the flow rate in the reforming channel varied greatly, and the study showed that the inlet velocity and reaction time interacted with each other. Although the fast inlet velocity can improve the mass transfer efficiency, the length of the flow channel needs to be reasonably designed to ensure that the substance reacts adequately. This study provides a theoretical basis for the optimization of microchannel reactors and lays the foundation for the practical application of methanol steam reforming in hydrogen fuel cell vehicles, demonstrating the great potential for promoting clean energy and renewable resources.