Phase behavior of methane hydrate in the presence of imidazolium ionic liquids and their mixtures

• Published in: Fluid Phase Equilibria
• Main Authors: Long, Zhen, He, Yong, Zhou, Xuebing, Li, Dongliang, Liang, Deqing
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Phase Equilibria; Ionic Liquid; Synergetic Effect; Methane Hydrate; Inhibitor; Science & Technology; Physical Sciences; Technology; Thermodynamics; Chemistry; Engineering; DUAL FUNCTION INHIBITORS; AQUEOUS-SOLUTIONS; SODIUM-CHLORIDE; EQUILIBRIUM; DISSOCIATION; TEMPERATURE; PRESSURE; WATER; MORPHOLINIUM; SOLVENTS; Physical; Chemical; Methane hydrate
• Online Access: http://ir.giec.ac.cn/handle/344007/14098; https://doi.org/10.1016/j.fluid.2017.02.008

The phase equilibrium conditions of methane hydrate in single ionic liquid aqueous solutions containing low dosage 1-ethyl-3-methylimidazolium nitrate ([Emim][NO3]) at mass fractions of 0.01, 0.025, 0.05 are measured in a pressure range of 3.50-15.0 MPa via an isochoric step-heating pressure search method. The thermodynamic inhibition effect of mixed ionic liquids containing [Emim[NO3] in conjunction with 1-ethyl-3-methylimidazolium chloride ([Emim][CI]) at low and high concentrations on methane hydrate formation is also investigated for the possible presence of synergistic effects. It is observed that for all the inhibitor systems containing [Emim][NO3] or [Emim[Cl], the inhibition effect increases progressively with the increased concentration and pressure. In addition, the mixture of [Emim][NO3] and [Emim][Cl] does not always exhibit synergetic effect on the thermodynamic inhibition of methane hydrate at higher concentrations up to 0.2 mass fraction. The higher concentrations are, the positive interactions between [Emim][NO3] and [Emim][[CI] possibly happen at higher pressures. (C) 2017 Elsevier B.V. All rights reserved.