Experimental Study on the Operation of Pressure Safety Valve in the Liquid Hydrogen Environment

In this study, a liquid hydrogen (LH2) safety valve evaluation device was developed to enable safe and stable performance testing of pressure safety valves (PSVs) under realistic cryogenic and high-pressure conditions. The device was designed for flexible use by mounting all components on a mobile frame equipped with wheels, and the pressurization rate inside the vessel was controlled through a boil-off gas (BOG) generator. Two experiments were conducted to investigate the effect of LH2 production rate on PSV operation. When the production of LH2 increased by about 2.4 times, the number of PSV operations rose from 15 to 20, and the operating pressure range shifted slightly upward from 10.68~12.53 bar to 10.68~13.2 bar, while remaining within the instrument’s error margin. These results indicate that repeated valve cycling and increased hydrogen production contribute to gradual changes in PSV operating characteristics. Additionally, the minimum temperature experienced by the PSV decreased with repeated operations, reaching approximately 77.9 K. The developed evaluation system provides an effective platform for analyzing PSV performance under realistic LH2 production and storage conditions.