Effect of liquid alkane on carbon dioxide hydrate formation

Abstract

Hydrophobic surface affects gas hydrate formation. It is an effective method to promote hydrate formation by adding hydrophobic materials into hydrate formation system. However, it is little known about the interaction between hydrate formation and macroalkane. n-Dodecane and n-tetradecane are selected as additives to investigate their effect on CO2 hydrate formation in this work. The addition of liquid alkanes effectively improves hydrate nucleation, shortens the induction time of CO2 hydrate formation, and improves the hydrate growth rate. In addition, the total CO2 uptake at the end of the experiments was increased in the presence of liquid alkanes. Compared with the addition of n-dodecane, n-tetradecane has a weaker effect on CO2 hydrate formation. Increasing the stirring rate can effectively reduce the induction time of hydrate formation and improve hydrate growth rate, but has little effect on gas storage capacity in hydrates. The experimental results also show that the increase of experimental pressure or the decrease of temperature is conducive to hydrate formation.