Effect of nitrogen crossover on purging strategy in PEM fuel cell systems
Effect of nitrogen crossover on purging strategy in PEM fuel cell systems
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DOI：
10.1016/j.apenergy.2013.06.057
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发表时间：
2013-11
期刊：
影响因子：
11.2
通讯作者：
A. Rabbani;M. Rokni
中科院分区：
文献类型：
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作者：
A. Rabbani;M. Rokni
对阳极再循环的质子交换膜燃料电池（PEMFC）系统中的氮窜现象进行了全面的研究，并讨论了相应的清除策略。当在汽车中使用时，这样的系统经受负载和外部操作条件的连续变化，使得在瞬态条件期间研究系统的动态性能变得重要。在这里开发的模型是能够预测氮交叉与堆栈的设计验证数据非常一致。结果表明，在纯再循环条件下，由于燃料电池中氮的累积，电压和系统效率下降。不同的吹扫技术进行了模拟，以解决氢气稀释的问题，在反应地点。发现3%的阳极渗出对于防止N2累积是限制的，并且将浓度水平保持在小于1%。采用氮气检测器模拟了自动启动阳极再循环吹扫的替代策略。据观察，吹扫间隔是电流密度和H2残留流量的直接函数。此外，在瞬时负载变化期间，与固定吹扫间隔策略相比，自动吹扫很好地满足了防止氮气水平上升的需要。该模型可作为汽车燃料电池系统阳极吹扫策略控制和开发的基础。
A comprehensive study on nitrogen crossover in polymer electrolyte membrane fuel cell (PEMFC) system with anode recirculation is conducted and associated purging strategies are discussed. Such systems when employed in automobiles are subjected to continuous changes in load and external operating conditions, making it important to investigate the dynamic performance of the system during transitory conditions. The model developed here is able to predict nitrogen crossover in excellent agreement with the design validation data of the stack. The results show that with pure recirculation, voltage and system efficiency decline due to nitrogen accumulation in fuel cell. Different purging techniques are simulated to address hydrogen dilution issue at reaction sites. Anode bleed out of 3% is found to be limit for prevention of N2buildup and retains the concentration levels to less than 1%. An alternate strategy for automatic initiation of anode recirculation purge was simulated by employing nitrogen detectors. It is observed that purge interval is a direct function of current density and H2residual flow rates. Moreover, during transient load changes, automatic purge catered well to prevent nitrogen levels from rising when compared to a fixed purge interval strategy. This model can be used as a base for control and development of anode purge strategies for automotive fuel cell systems.