CFD simulation for charge–discharge cycle of cryo-adsorptive hydrogen storage on activated carbon

Abstract

The hydrogen storage technology is one of the most difficult technical challenges for realizing the hydrogen power fuel cell vehicle scale application. In recent years, the activated carbon with high surface area reveals a good capability in hydrogen storage, and becomes the central issue of the hydrogen storage research. In addition, the activated carbon adsorption can be significantly enhanced at cryogenic temperatures. In this study, the charge–discharge cycle of hydrogen storage adsorption on activated carbon at cryogenic temperature is simulated. The computational fluid dynamics (CFD) model based on the mass, momentum and energy conservation equations of the hydrogen storage system, is applied to simulate the processes of charging, discharging and dormancies in the case of the liquid nitrogen. Dynamic thermal boundary condition is proposed for better description of moving liquid–gaseous interface of nitrogen. The linear driving force (LDF) model is successfully applied to describe kinetics of cryo-adsorption. The adsorbed phase hydrogen makes contribution to effective heat capacity of cryo-adsorption system. The computational fluid dynamics model is well validated by cryo-adsorption experiments. The comparisons show that the mass balance of hydrogen in gaseous and adsorbed phases is verified, the simulated pressure agree well with experimental, and there are identical trends between the simulated temperatures and experimental. The model is applicable for optimizing the cryo-adsorptive hydrogen storage system.