(96e) Addressing Critical Issues in Microscale Fuel Processing: Demonstration of an Integrated Silicon Microreactor Based Methanol Steam Reformer

As fuel cells gain attention as potential energy solution of the future, one of the most promising field of application is portable power, as a prominent alternative to batteries. In applications where the power requirements are low but weight and volume are critical, it is believed that miniature fuel cells will be preferred over conventional batteries. However, the success of fuel cell technology for portable power depends heavily on development of an efficient way of delivering fuel to the cell. Methanol reforming offers an attractive source of hydrogen for fuel cell systems for portable power. The greatest obstacle to realization of these systems is the extraction of hydrogen from the hydrocarbon fuel, i.e. the fuel processing part. Considerable efforts have been made to develop an integrated fuel processor/fuel cell system, however, several issues and challenges persist. Based on the literature and research conducted, several of the key issues are identified. Miniaturization of system components and thermal management in miniature systems are perhaps the most crucial challenges for microscale fuel processors. Through this work, we are trying to address these crucial system issues. Silicon microfabrication technology is explored to achieve miniaturization. Our research group is pursuing an effort to develop silicon microreactors for in-situ methanol reforming, as a critical component of fuel processor. In this study, a silicon microreactor-based catalytic methanol steam reforming reactor was designed and fabricated in the context of complete thermal integration to directly address the heat management issues. The design is made where vacuum packaging chips, thin film heater, and temperature sensors are directly embedded with the microreactor to simulate an integrated steam reformer in an overall fuel processing scheme. Detailed experiments are carried out to quantify heat losses through various pathways from the planar microreactor structure. The result provides fundamental insight in understanding of critical thermal transfer issues of an integrated microreactor system such as transfer of heat between reactor components, control of temperature, insulation, and heat losses. It is also expected to significantly expand understanding of the critical limitations imposed by the steam reformer in an overall thermal integration of a micro fuel processor.