Effect of ionic liquid on CH4 hydrate formation thermodynamics

Abstract

In this work, experiment results of CH₄ hydrate formation pressure in four imidazole ionic liquid solutions have been determined. Hydrogen bond interaction between ionic liquids and water molecules has been simulated by conductor like screening model for real solvents model (COSMO-RS). Hydrogen bond energy has been calculated. Variation of hydrogen bond energy between ionic liquid and water molecules was obtained by COSMO-RS simulation. The inhibition effect of four ionic liquids on water activity was listed from strong to weak in order: [BMIm]Br > [BMIm]BF₄ > [BMIm]PF₆ > [OMIm]BF₄. Compared with experimental results of CH₄ hydrate formation pressure in ionic liquid aqueous solution, hydrogen bond interaction between ionic liquid and water molecules obtained by COSMO-RS is basically consistent with experimental results of hydrate formation pressure in ionic liquid. The study could provide better theoretical basis for ionic liquid selection on gas hydrate study. The simulation would be better as one method to chose admirable ionic liquid in the area of hydrate additives usage.