High temperature PEMFC and the possible utilization of the excess heat for fuel processing

In this paper simple heat balances are calculated for systems with methanol and methane reformers in combination with a high temperature PEM fuel cell. In the methanol system at least 11.1% of the fuel energy can be saved by using the excess heat from the fuel cell for vaporization of water and methanol if the cell is operated at temperatures between 150 and 200∘C. Similarly, in the methane system, 9.6% can be saved under equivalent conditions. Integration of a high temperature PEM fuel cell with a metal hydride system based on NaAlH4 is considered briefly with respect to desorption heat. Dead-end operation is studied, and stable performance is seen for 100 min at 150∘C without purging. Finally, experiments are reported indicating that preheating of the air has no influence on the fuel cell performance at 150 or 200∘C under moderate load.