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.