Abstract Ammonia is a promising energy carrier and carbon-free fuel for power generation using combined-cycle gas turbines. However, its use results in the generation of relatively large amounts of NOx in the combustor. To address this issue, we propose a combined-cycle configuration including exhaust gas recirculation (EGR), in which the gas turbine is operated under fuel-rich conditions and the uncombusted hydrogen is burned in the heat-recovery steam generator (HRSG). Thus, hydrogen in the flue gas of the gas turbine increases the output power and improves the thermal efficiency of the system. Furthermore, in the combined system with EGR, the exhaust gas does not contain O2 and the combustion temperature can be reduced without altering the equivalence ratio. The proposed system is evaluated by thermodynamic modeling, and we find that low NOx emissions can be achieved while maintaining high thermal efficiency. Cold EGR is likely to be required to maintain the turbine inlet temperature below a technically feasible level, and a tradeoff between thermal efficiency and the NOx concentration at the combustor outlet is observed. The ideal operating conditions for this process thus depend on the technically feasible turbine inlet temperature, EGR ratio, and the permissible NOx concentration in the exhaust gas.

中文翻译：

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在富燃料条件下运行的以氨为燃料的联合循环燃气轮机过程的热力学评估

摘要 氨是一种很有前途的能源载体和无碳燃料，可用于联合循环燃气轮机发电。然而，它的使用导致燃烧器中产生相对大量的NOx。为了解决这个问题，我们提出了一种包括废气再循环 (EGR) 的联合循环配置，其中燃气轮机在富含燃料的条件下运行，未燃烧的氢气在热回收蒸汽发生器 (HRSG) 中燃烧。因此，燃气轮机烟气中的氢气增加了输出功率并提高了系统的热效率。此外，在与 EGR 的组合系统中，废气中不含 O2，可以在不改变当量比的情况下降低燃烧温度。所提出的系统通过热力学模型进行评估，我们发现可以在保持高热效率的同时实现低 NOx 排放。可能需要冷 EGR 以将涡轮机入口温度保持在技术上可行的水平以下，并且观察到热效率和燃烧器出口处的 NOx 浓度之间的权衡。因此，该过程的理想运行条件取决于技术上可行的涡轮入口温度、EGR 比和废气中允许的 NOx 浓度。