Abstract:

To solve the problem of spatiotemporal mismatch of energy in liquid hydrogen energy storage and to preferentially match suitable application scenarios, the cold energy is recovered by the combined cascade storage of liquid neon, liquid nitrogen, carbon dioxide (CO₂), and other working substances, and then the pre-cooled bypass hydrogen is incorporated into the liquefier to compensate the cold capacity and reduce the power consumption. Aspen HYSYS software is used to establish the processes of cold storage, cold release, and cold energy compensation. While giving priority to recovering cold energy in the low temperature zone, optimization is carried out from aspects such as coupling the waste heat utilization cycle of transcritical CO₂ fuel cells. The results showed that the non-pressurized cold energy storage was better to directly compensate the liquefier, and the hydrogen outlet temperature reached 273.7 K, while exergy efficiency was 81.65%. After pressurization, it focused more on increasing output work, and expanders generated more cold energy at high-temperature zones. For example, under the condition of expansion at 130 K, the hydrogen outlet temperature was 299 K, while energy efficiency was 86.07% and exergy efficiency was 50.86%. The simulation of hydrogen liquefaction cycles of helium two-stage expansion Brayton cycle and hydrogen dual-pressure Claude cycle showed that compensating cold capacity could effectively reduce the energy consumption and increase the exergy efficiency.

Key words: hydrogen, liquefaction, cold energy recovery and utilization, phase change, carbon dioxide

摘要：

为了解决液氢储能中能量时空错配问题及优先匹配合适应用场景，采用液氖、液氮、二氧化碳等工质联合梯级蓄冷的方法回收冷能，而后预冷旁路氢气再并入液化器补偿冷量以减小耗功。使用Aspen HYSYS软件建立蓄冷、释冷、冷能补偿等流程，并在优先回收低温区冷能的同时，从耦合跨临界CO₂燃料电池余热利用循环等方面进行优化。结果表明，无增压蓄冷更有利于直接补偿液化器，氢气出口温度可达到273.7 K，㶲效率为81.65%。增压后蓄冷更侧重于增加输出功，且膨胀产生更多高温区冷能，如在130 K膨胀时氢气出口温度为299 K，能量效率为86.07%，㶲效率为50.86%。对氦布雷顿两级膨胀和氢双压克劳特两种氢液化循环模拟计算均表明，补偿冷量可以有效降低液化耗功且提高㶲效率。

关键词: 氢, 液化, 冷能回收利用, 相变, 二氧化碳