139 / 2024-03-01 11:10:28

Effects of cushion gas and operating parameters on hydrogen storage capacity in lined rock caverns (LRC)

Underground hydrogen storage; Lined rock cavern; Thermodynamic state; Storage capacity; Operating parameters

Hydrogen storage in lined rock cavern (LRC) provides versatile site selection, along with safety and stability, making it a crucial choice. Therefore, a thermodynamic mathematical model was established to describe hydrogen storage in LRC. This model is founded on the principles of mass, momentum, and energy conservation, while accounting for the authentic compressibility of hydrogen. The thermodynamic fluctuations throughout the seasonal cycle in LRC were calculated using the COMSOL Multiphysics software. The results indicate that when the hydrogen storage reaches the operating pressure, the lower the cushion gas pressure, the greater the hydrogen injection amount, and the higher the utilization rate of storage capacity. With a cushion gas pressure of 3 MPa, the storage capacity utilization rate exceeds that at 15 MPa by 41%. The injection rate of 0.5 kg/s results in a temperature increase of 12 ℃ compared to 0.27 kg/s, indicating twice the temperature rise at the 0.27 kg/s injection rate. An increase in injection temperature corresponds to higher temperature within the hydrogen storage cavern upon completion of gas injection, thereby reducing the time needed for gas injection to reach maximum operating pressure. A lower initial temperature of cavern results in a longer time for hydrogen storage to reach maximum operating pressure.