Study on Performance Comparison of Two Hydrogen Liquefaction Processes Based on the Claude Cycle and the Brayton Refrigeration Cycle

Hydrogen liquefaction is an essential section for efficient storage and transportation of hydrogen energy. Both the Claude cycle and Brayton refrigeration cycle are available for large-scale hydrogen liquefaction systems. Two large-scale hydrogen liquefiers with the liquefaction capacity of 120 t/d based on the Brayton refrigeration cycle and the Claude cycle, respectively, are analyzed and compared in this study. Sensitivity analysis is used to optimize the parameters of two liquefaction systems in HYSYS. According to the results, the exergy loss and specific energy consumption of the Claude liquefier are 18.98 MW and 5.62 kWh/kg_LH, which are 6.6% and 4.4% less than those of the Brayton liquefier, respectively. Exergy analysis reveals the exergy loss of compression and expansion systems in the Claude liquefier is less than that of the Brayton liquefier, while the exergy loss of the throttle valve in the Claude liquefier is more notable. In addition, the molar flow rate of hydrogen used as refrigerant in the Claude liquefier is 10.6% less than that of refrigerant in the Brayton liquefier. Owing to the smaller size requirements of equipment and the lower specific energy consumption, the Claude cycle is more suitable for large-scale hydrogen liquefaction processes.