The production of liquefied natural gas (LNG) is a high energy-consuming process. The study of ways to reduce energy consumption and consequently to reduce operational costs is imperative. Toward this purpose, this study proposes a hybrid system adopting a mixed refrigerant for the liquefaction of natural gas that is precooled with an ammonia/water absorption refrigeration (AR) cycle utilizing the exhaust heat of a molten carbonate fuel cell, 700°C and 2.74 bar, coupled with a gas turbine and a bottoming Brayton super-critical carbon dioxide cycle. The inauguration of the ammonia/water AR cycle to the LNG process increases the cooling load of the cycle by 10%, providing a 28.3-MW cooling load duty while having a 0.45 coefficient of performance. Employing the hybrid system reduces energy consumption, attaining 85% overall thermal efficiency, 53% electrical efficiency and 35% fuel cell efficiency. The hybrid system produces 6300 kg.mol.h⁻¹ of LNG and 146.55 MW of electrical power. Thereafter, exergy and sensitivity analyses are implemented and, accordingly, the fuel cell had an 83% share of the exergy destruction and the whole system obtained a 95% exergy efficiency.

中文翻译：

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一种结合熔融碳酸盐燃料电池的吸收式制冷新型混合液化天然气工艺

液化天然气（LNG）的生产是一个高能耗的过程。研究降低能耗从而降低运营成本的方法势在必行。为此，本研究提出了一种混合系统，采用混合制冷剂进行天然气液化，该系统通过氨/水吸收制冷 (AR) 循环进行预冷，利用熔融碳酸盐燃料电池的废热，700°C 和 2.74 bar，再加上一个燃气轮机和一个底部布雷顿超临界二氧化碳循环。将氨/水 AR 循环引入 LNG 工艺后，循环的冷却负荷增加了 10%，提供了 28.3 MW 的冷却负荷负荷，同时具有 0.45 的性能系数。采用混合动力系统降低能耗，整体热效率达到85%，53% 的电力效率和 35% 的燃料电池效率。混合动力系统产生 6300 kg.mol.h⁻¹ LNG 和 146.55 MW 电力。此后，实施火用和灵敏度分析，因此，燃料电池具有 83% 的火用破坏份额，整个系统获得了 95% 的火用效率。