Optimization On The Key Processes Of Methanol Autothermal Reforming System For PEMFC

Exergy analysis of a practical hydrogen generating system for PEMFC was performed in this paper, with the aim of providing some ways to decrease the cost and to keep the capacity of hydrogen generation to the desired extent. Results demonstrated that the most dominant destruction of exergy within the system was found to occur in the reformer and the catalytic combustion heat exchanger (CCHE).Their ratios of exergy loss accounted for 25.03% and 24.95%, respectively, of the whole system. So, the reformer and CCHE are two key subsystems of methanol autothermal reforming system, which needed to be optimized.To optimize the reforming process, a complete thermodynamic analysis of autothermal methanol reforming over a wide range of A/M (molar air to methanol) and W/M (molar water to methanol) was described. The optimal W/M is around 1.5–2.0 and A/M is around 1.5. Under these conditions, moles of generated hydrogen per mole methanol are 1.93–2.04, and there will be no deposition of solid carbon, while the carbon monoxide concentration is low. Based on the equilibrium composition analysis, some process improvements were presented to minimize the exergetic destruction in the reforming process. In addition, a novel method was proposed to avoid the complexity of equilibrium composition analysis.As the other key subsystem with remarkable exergetic destruction, CCHE is...