Experimental Study on the Formation of CO2-TBAB Hydrate with Low-Concentration Small-Molecule Alcohols

The effects of small-molecule alcohols at low concentrations on the formation of the CO2-TBAB hydrate are investigated in this study. The results indicate that the low-concentration small-molecule alcohols can promote kinetics of CO2-TBAB hydrate formation with a negligible effect on the phase equilibrium conditions by taking methanol as a representative. The induction time first decreases and then increases with increasing methanol concentration due to the amphiphilicity of the methanol, where the methanol at 0.10 wt % exhibits the best promoting effect as the induction time is reduced by 80.5% compared to that without methanol at 1.0 MPa. As the pressure increases, the promoting effect of the methanol is gradually weakened, and the methanol exhibits a dual effect on the hydrate kinetics at 1.6 MPa, that is, transforming from the kinetic promoter to the inhibitor with the increase of concentration.