Methanol Steam Reformer on a Silicon Wafer

Abstract

A study of the reforming rates, heat transfer and flow through a methanol reforming catalytic microreactor fabricated on a silicon wafer are presented. Packed bed microchannel reactors were fabricated using silicon DRIE, followed by wafer bonding. The reactor bed was subsequently filled with catalyst particles. Thermal control is achieved through on-chip resistive heaters, whereby methanol steam reforming reactions were studied over a temperature range from 180-300 degrees C. Three simulations of varying complexity, including three-dimensional (3-D), quasi-3-D, and I-D models, were developed. Comparison of the models with experimental results shows good agreement over a range of operating conditions. We found that Amphlett's kinetics for methanol reforming provided accurate results, and that for our operating conditions the reforming reaction could be modeled without mass transport considerations. The I-D model provided a rapid analytical tool to assess the performance of the microreactor. Use of such computationally efficient design tools provides an effective means to analyze the performance of microreactor designs prior to fabrication and test. Hence, reformer geometry, catalyst loading, and operating parameters can be optimized to afford the desired hydrogen output and conversion. Concepts for insulating the reactor while maintaining small overall size are further analyzed.