Thermodynamic analysis of low-temperature and high-pressure (cryo-compressed) hydrogen storage processes cooled by mixed-refrigerants

Abstract

Cryo-compressed hydrogen (CcH2) is a promising hydrogen storage method with merits of high density with low power consumption. Thermodynamic analysis and comparison of several CcH2 processes are conducted in this paper, under hydrogen storage conditions of 10–100 MPa at 60–100 K. Mixed-refrigerant J-T (MRJT), nitrogen/neon reverse Brayton (RBC) and hydrogen expansion are employed for cooling hydrogen, respectively. Combined CcH2 processes such as MRJT + neon-RBC are proposed to reach higher CcH2 density at lower temperatures (<80 K). It was indicated that the specific power consumptions (SPC) of MRJT processes are obviously lower than those of nitrogen/neon-RBC or hydrogen expansion processes. For a typical storage condition of 50 MPa at 80 K, MRJT CcH2 process could achieve hydrogen density of 71.59 kg m−3, above liquid hydrogen. While its SPC of 6.42 kWh kg−1 is about 40% lower than current dual-pressure Claude hydrogen liquefaction processes (10.85 kWh kg−1).