Kinetic Analysis on Spontaneous Combustion of Pressurized Hydrogen in Tubes

Highly pressurized hydrogen storage is considered as one of the best methods currently due to its economic performance. However, the highly pressured storage technology is facing the threat of spontaneous combustion of high-pressure leakage, and there is still a lack of research on the kinetics of chemical reactions in the spontaneous combustion process, which greatly restricts the development of safe and efficient hydrogen-storage technology. Therefore, in this study, a three-dimensional simulation using the open-source packages OpenFOAM with a detailed kinetic model is proposed to analyze the hydrogen spontaneous combustion process in tubes. Subsequently, the effects and mechanisms of release pressures and tube geometry parameters are studied by means of kinetic simulation. The results show that the magnitude of the release pressure and tube diameter and length directly affects the spontaneous ignition and the location. In order to get more deep insights into the pressurized hydrogen release, reaction path analysis is performed. Three different hydrogen-consumed channels are found by reaction path analysis. The special performances found in spontaneous ignition with different release pressures and tube geometry parameters are caused by the competition between the chain-terminating channel and chain-branching channel. This work provides novel insights to understand the hydrogen spontaneous combustion process and enhances the theoretical basis for seeking safe hydrogen-storage means.