Modeling and improving liquid hydrogen transfer processes
Albert Gil-Esmendia, Robert Flores, Jack Brouwer
Abstract
Hydrogen will play a pivotal role in reducing global carbon emissions. Cryogenic liquid hydrogen -LH 2 - is a promising storage and transportation solution. However, LH 2 transfer processes are complex, and the safe and efficient transfer operations of this fluid require deep and precise understanding. This study extends an existing physics-based model to simulate the dynamics of pressure difference-driven and pump-driven LH 2 transfer operations between a supply and receiving LH 2 storage tanks. A critical model output is the predicted LH 2 boil-off and venting, which is crucial for evaluating system design, safety, efficiency, and environmental impacts. Results show that LH 2 pressure-driven transfer processes evaporate up to 20 % of LH 2 to pressurize the supply tank and deliver warmer LH 2 . Switching to a pump-driven transfer process reduces venting to 0 % to 16 % of total hydrogen transferred, where venting is lowest for slow transfer rates and when receiving tank initial pressure is low. Maximum transferred LH 2 mass to a receiving tank can be increased by 6.5 % and 13 % versus flow rates that minimize transfer time or venting by manipulating flow rate and initial tank pressures. • A physical model is used to simulate pressure-driven and pump-driven LH 2 transfers. • Fast transfer flow rates increase boil-off venting from 0 to 15 % of transferred LH 2 . • Pressure-driven processes evaporate up to 20 % of LH 2 to pressurize the primary tank. • Pump-driven transfer processes reduce venting up to a 15 % of total transferred LH 2 . • Specific operating parameters can reduce or eliminate venting during LH 2 transfer. • Parameters can be tailored to optimize transfer time or LH 2 storage density.