Design, Analysis and Optimization of Refrigerant Cycle in Cryo-compressed Hydrogen Storage Process

Large-scale application of hydrogen requires safe, reliable and efficient storage technology. Compared with current hydrogen storage technologies, cryo-compressed hydrogen (CcH₂) has the advantages of high hydrogen storage density, lower energy consumption, no para-to-ortho hydrogen conversion, etc. In this article, several CcH₂ processes under different hydrogen storage parameters were simulated and compared, including mixed-refrigerant processes and reverse Brayton processes. The results indicated that the exergy efficiency of mixed-refrigerant processes is significantly higher than that of other processes. The mixed-refrigerant precooling and propane precooling were also compared, and the results showed that the mixed-refrigerant precooling can further reduce power consumption and improve efficiency. The specific power consumption and hydrogen storage density for the dual mixed-refrigerant process at 80 K and 50 MPa are 6.104 kWh/kg and 71.71 kg/m³, respectively. Under similar hydrogen storage density, the power consumption of dual-MRJT is about 43% lower than that of typical dual-pressure Claude hydrogen liquefaction process (10.85 kWh/kg).