In solid oxide fuel cell (SOFC) system with anode-exhaust gas recirculation (AEGR), a part of the depleted anode-exhaust gas is recirculated and mixed with fresh natural gas prior to entering the reformer, resulting in a high potential of direct current-efficiencies of up to 65%. However, for SOFC systems, it is of crucial importance to monitor relevant characteristic parameters and keep them within safe and durable operating limits. Such characteristic parameters are oxygen-to-carbon-ratio and fuel utilization, which must not exceed system-specific thresholds. Monitoring and control of these characteristic parameters is not trivial and a challenging task due to the enhanced system complexity. The authors present an approach and studies for determination and controlling characteristic parameters in an SOFC system with AEGR based on oxygen sensors. Therefore, the oxygen sensors, being a mature and easily available technology, are aimed to be in the fuel gas path at anode inlet and outlet of an SOFC-stack. Analytical correlations of the output value of oxygen sensors to characteristic parameters and simulative studies on the basis of a reference natural gas composition are shown. Additionally, first results of experimental studies of oxygen sensors in representative gas compositions for the anode inlet and outlet of an SOFC system with AEGR are presented.

中文翻译：

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通过氧传感器在线表征具有阳极废气再循环的 SOFC 系统中的运行参数

在具有阳极废气再循环（AEGR）的固体氧化物燃料电池（SOFC）系统中，一部分耗尽的阳极废气在进入重整器之前再循环并与新鲜天然气混合，导致直流电的高电位- 效率高达 65%。然而，对于 SOFC 系统而言，监控相关特性参数并将其保持在安全和持久的运行范围内至关重要。这些特征参数是氧碳比和燃料利用率，它们不得超过系统特定的阈值。由于系统复杂性的增加，对这些特征参数的监测和控制并非微不足道且具有挑战性的任务。作者提出了一种方法和研究，用于确定和控制基于氧传感器的具有 AEGR 的 SOFC 系统中的特征参数。因此，氧传感器作为一种成熟且易于获得的技术，旨在用于SOFC电堆阳极入口和出口的燃料气路径中。显示了氧传感器输出值与特征参数的分析相关性以及基于参考天然气成分的模拟研究。此外，还介绍了具有 AEGR 的 SOFC 系统阳极入口和出口的代表性气体成分中氧传感器的实验研究的初步结果。