Hydrogen Storage Performance in Hydrates under the Action of DIOX

Hydrate hydrogen storage technology is usually restricted by extreme phase equilibrium conditions and slow formation kinetics. Although 1,3-dioxolane (DIOX) has been identified as a bifunctional promoter, the coupling effects of various operating parameters on its hydrogen storage performance still need to be quantitatively evaluated. In this study, the formation characteristics of H2 hydrate were systematically studied by using a high-pressure visual reactor, aiming to evaluate the specific effects of DIOX concentration, stirring rate, initial pressure, and initial temperature. The experimental results quantitatively reveal that there is a clear trade-off between hydrogen storage capacity and formation rate. Under the specific conditions of a DIOX concentration of 5.56 mol % and a stirring rate of 100 rpm, the system reached a maximum hydrogen storage capacity of 0.21 mol. Kinetics and visualization analysis show that a low stirring rate can maintain a stable gas–liquid interface, promote the orderly dissolution of hydrogen molecules, and enter the hydrate cage structure. In addition, a secondary formation phenomenon was observed during the DIOX-promoted hydration process, which helped to improve the overall hydrogen storage rate. These quantitative results provide solid experimental data support for optimizing the process parameters of the hydrate hydrogen storage system.