Abstract: Slow rate of methanol oxidation and its crossover are two major challenges for direct methanol fuel cells(DMFC).The sluggish kinetics can be relieved by elevating cell temperature which, however, leads to other problems like membrane dehydration.To solve these problems, it is proposed that a methanol electrolytic reformer (MER) is combined with polymer electrolyte membrane fuel cell(PEMFC) system.Working at elevated temperature, the MER provides hydrogen for the PEMFC and is driven by power provided by the PEMFC.Essential components included in this system are described and flows of mass, enthalpy and exergy are presented.Thermodynamic analysis shows that exergy destructions occur in main components, i.e.,PEMFC and MER.The voltage of MER is an important parameter influencing the efficiency of the system. Rising temperature in MER,MER voltage required significantly decreases, but exergy losses caused by heat dissipation and heat transfer increase exponentially due to the intensified evaporation of methanol solution.To mitigate evaporation, low methanol concentration and high pressure could be necessary.When MER works at higher methanol concentration, higher pressure is required for efficient operation.The overall performance and efficiency of this system is much better than that of a DMFC.Without carbon monoxide in hydrogen generated, comparing with a competitive system in which a thermal methanol steam reformer is incorporated, this system has potentials to be built simplier.

Key words: methanol reforming, electrolysis, hydrogen production, fuel cell

摘要： 为解决直接甲醇燃料电池中甲醇氧化活性低及甲醇穿透问题,提出一种新型的电解重整式甲醇燃料电池系统。在系统中,高温电解重整器重整甲醇为常温燃料电池供氢,燃料电池的部分电能供给电解重整器使用。通过对系统的物料流、焓流、有效能流的分析,确定了系统中的不可逆因素。结果表明:电解重整器电压是影响系统效率的重要参数;升高重整器温度可以显著降低其电压,但必须采用合理的压力、甲醇溶液浓度以抑制甲醇溶液的蒸发,降低热量损失。与传统的直接甲醇燃料电池系统以及高温甲醇热重整联合质子交换膜燃料电池系统相比,该系统性能较高、结构紧凑。

关键词: 甲醇重整, 电解, 制氢, 燃料电池