Effect of ZIF-8 on Methane Hydrate Growth Kinetics in Oil-Water Systems

The rate of hydrate generation is the key to the implementation of solid-state gas storage and transportation technology by the hydrate method. ZIF-8, a hydrothermally stable metal-organic framework (MOF) material, has been shown to significantly contribute to hydrate nucleation and growth. However, the growth kinetics of hydrates in ZIF-8 promoter systems are not yet clear. Therefore, in this paper, the growth kinetics of methane hydrate experiments were investigated in oil-water systems containing a ZIF-8 promoter in a high-pressure visible reactor to systematically investigate the effect of ZIF-8 concentration on the growth pattern of methane hydrates. The results of the experiments showed that the induction time of hydrate decreased from 1.33 to a minimum of 0.74 h with decreasing water-oil ratio at 0.05 mg/mL and the induction period of hydrate decreased from 5.75 to 0.05 h with increasing ZIF-8 content from 0 to 0.05 mg/mL at a water-oil ratio of 550:50, with a maximum reduction of 99.1%. The addition of ZIF-8 in the oil phase promoted the gas-liquid mass transfer process, provided nucleation sites for methane hydrate, increased the chance of hydrate formation, significantly promoted the nucleation process, and reduced the induction time of methane hydrate formation.