(36b) Thermal Integration Issues in Micro Fuel Processor: Development of an Integrated Silicon Microreactor Based Methanol Steam Reformer as a Model

The processing of high density liquid hydrocarbon fuels appears to be the most promising method of supplying a hydrogen stream for feeding portable fuel cells. Because of size and portability, microreactor technology has shown promising results in the field of fuel processing to convert hydrocarbon fuels to hydrogen, for the production of electricity. Microreaction can facilitate highly compact power sources through integration of a fuel cell with all the unit operation components of a fuel processor along with microstructured sensors, actuators and other ?balance of plant? devices.

A number of crucial challenges exist for the realization of practical micro fuel processors. Considerable efforts are being made to develop such an integrated system; however there are major hurdles and several universal challenges exist. Based on the literature and research conducted by our group, several of the key issues are observed with fuel processing at small scale. Among these, the management of heat in a compact format is perhaps the most crucial challenge for micro scale fuel processors.

The fuel processor needs effective thermal coupling to allow transfer of energy from the heat producing combustor to the vaporizer and the endothermic steam reformer. Coupling endothermic and exothermic components of the fuel processor and minimizing losses can achieve high thermal efficiency. However, such coupling must be accomplished in a manner that permits the maintenance of specific temperatures in the various components and maintains the surface of the package near room temperature. We are developing various vacuum packaging schemes of microreactors that can provide an effective means of insulation.

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 issue. 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. This study is expected to significantly expand understanding of the critical limitations imposed by the steam reformer in an overall thermal integration of a micro fuel processor. Results of these experiments will be presented at the meeting.