Cryogenic supercritical hydrogen, as a physical hydrogen storage method, is used to increase the volume and weight of hydrogen storage density without phase change by means of a combination of cooling and pressurization. In this study, a cryogenic supercritical hydrogen storage system coupled with mixed refrigerant and gas expansion cycle is proposed for the cryogenic supercritical hydrogen cooling thermodynamic process. The cryogenic supercritical hydrogen storage system proposed in this paper can compress and cool hydrogen at ambient temperature and pressure to 70 K and 30 MPa, and the hydrogen storage density at this state point is 72.53 kg/m3. Aspen HYSYS software is used to simulate and analyze the system process, and 29 key variables in the system are optimized by genetic algorithm with specific energy consumption (SEC) as the objective function. The system performance is analyzed by varying the expansion refrigeration cycle work gases, and helium, hydrogen and neon are selected for horizontal comparison, and the energy, exergy and heat transfer performance of the three gases are analyzed in detail at the end of the optimization. The results show that neon has the best performance as the expansion cycle working medium, with the SEC of5.87 kWh/kgH2.The theoretical minimum SEC is 2.92 kWh/kgH2 and the exergy efficiency (EXE) is 49.74 %.

中文翻译：

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低温超临界储氢系统耦合混合制冷剂与气体膨胀循环的设计与优化


低温超临界氢作为一种物理储氢方法，用于通过冷却和加压相结合的方式在不发生相变的情况下增加储氢密度的体积和重量。本研究提出了一种低温超临界储氢系统，采用制冷剂和气体混合膨胀循环，实现低温超临界氢气冷却热力学过程。本文提出的低温超临界储氢系统可以在环境温度和压力下将氢气压缩和冷却至 70 K 和 30 MPa，在该状态点的储氢密度为 72.53 kg/m3。采用 Aspen HYSYS 软件对系统过程进行仿真分析，以比能耗 （SEC） 为目标函数，通过遗传算法优化系统中的 29 个关键变量。通过改变膨胀制冷循环工作气体来分析系统性能，选择氦、氢和氖进行水平比较，优化结束时详细分析三种气体的能量、用能和传热性能。结果表明，氖作为膨胀循环工作介质的性能最好，其性能曲线为5.87 kWh/kgH2，理论最小性能曲线为2.92 kWh/kgH2，用能效率（EXE）为49.74 %。