Study on Dissociation Characteristics of Type II Hydrogen Hydrate with ECP, CP, THF and 1, 3-DIOX Promoter

Solidified Hydrogen Storage is the cleanest hydrogen storage method, which has a unique advantage from other traditional hydrogen storage methods, and is a relatively ideal and promising hydrogen storage technology. Among them, the use of sII type hydrogen hydrate to store hydrogen is the focus of current research, but its dissociation process and stability law are still unclear. In order to reveal the stability rule of hydrogen hydrate under low pressure, low pressure dissociation experiments were conducted on four types of sIIhydrogen hydrate, THF, 1, 3-DIOX, ECP and CP. The dissociation rule of four types of sII hydrogen hydrate under different temperatures was studied mainly by direct depressurization method. The results show that when the temperature is 248K, the dissociation ratio of hydrogen hydrate is as follows: CP-H2 > 1,3-DIOX-H2 > ECP-H2 > THF-H2; when the temperature is 253K, the dissociation ratio of hydrogen hydrate is as follows:CP-H2 > ECP-H2 > 1,3-DIOX-H2 > THF-H2; when the temperature is 258K, the dissociation ratio of hydrogen hydrate is as follows: 1, 3-DIOX-H2 > CP-H2 > ECP-H2 > THF-H2; when the temperature is 264K, the dissociation ratio of hydrogen hydrate is as follows: THF-H2 > 1,3-DIOX-H2 > ECP-H2 > CP-H2;when the temperature is 268K, the dissociation ratio of hydrogen hydrate is as follows: CP-H2 > 1, 3-DIOX-H2 > ECP-H2 > THF-H2; when the temperature is 273K, the dissociation ratio of hydrogen hydrate is as follows: 1,3-DIOX-H2 > THF- H2 > ECP-H2 > CP-H2. It is also found that the abnormal dissociation temperature range of the four hydrogen hydrates is 248K-273K, and the dissociation ratio of 1,3-DIOX-H2 hydrate is the lowest at 258K, which is 49.23%. The lowest dissociation ratio of THF-H2 hydrate is 46.38% at 268K. At 273K, the decomposition rates of ECP-H2 and CP-H2 hydrate are the lowest, which are 42.3% and 40.45%, respectively. Hydrogen hydrate must be stored below 273K, but the lower temperature is not the better. The research results provide a theoretical basis for the stable storage and transportation of Solidified Hydrogen Storage under low pressure. Stable storage of hydrogen hydrate under low pressure without dissociation is feasible in principle. It is recommended that further systematic experiments be conducted to explore stable preservation at lower pressures.