Phase Equilibria of CO2 Hydrate in the Aqueous Solutions of N-Butyl-N-methylpyrrolidinium Bromide

Abstract

This work aims at reporting the dissociation pressures of carbon dioxide simple hydrates in the aqueous solution of N-butyl-N-methylpyrrolidinium bromide at four different mass fractions (0.01, 0.05, 0.10, and 0.20) in the pressure range of (2.34 to 3.13) MPa and in the temperature range of (276.63 to 280.63) K, respectively. The experiment was carried out by employing an isochoric pressure-search method. The obtained CO2 hydrate equilibrium data in pure water were compared with those from literatures, and the good agreement demonstrated the good reliability and accuracy of our experimental apparatus and method. The equilibrium data measured with the addition of N-butyl-N-methylpyrrolidinium bromide showed that it acted as a thermodynamic inhibitor to change the hydrate stable region to lower temperature or higher pressures. Also, with the mass fraction increasing, the inhibition effect became stronger. However, it was a weak thermodynamic inhibitor compared with some conventional ones.