Investigation of promotion effect of ZIF-8 suspensions on hydrate formation

Abstract Porous adsorption materials have been used to promote hydrate formation in the development of hydrate-based technology. In this study, the effect of ZIF-8 suspensions on the formation kinetic of methane hydrate was investigated systematically. The experimental results show that the presence of ZIF-8 suspensions can effectively reduce the induction time of methane hydrate formation, and the higher the amount of addition, the shorter the induction time. We found the transition mechanism of inhibition-promotion effect of ZIF-8. At low pressure, gas adsorption and hydrate formation compete to capture the dissolved methane, limiting the further hydrate growth. At high pressure, the gas consumption rates are determined by the hydrate formation in bulk phase at the early stage. When the mass transfer resistance is large, conversion of adsorbed gas provides additional source for hydrate formation. The promotion effect of ZIF-8 on hydrate formation emerges at the initial pressure of 6.5MPa, and the methane gas consumption increases significantly with the increase of ZIF-8 addition.