Inhibition effect of ionic liquids and their mixtures with poly(N-vinylcaprolactam) on methane hydrate formation

• Ionic liquids prepared in this study acted as both thermodynamic and kinetic hydrate inhibitors.
• Excessive dosage of ionic liquids (10 wt%) inhibited CH4 hydrate formation thermodynamically.
• Ionic liquids of pyrrolidinium and imidazolium cations with BF4− show the remarkable kinetic inhibition effect.
• Ionic liquids having alkyl chain with Br− show the weak kinetic inhibition performance.
• Several mixtures of ionic liquid and PVCap exhibited enhanced kinetic inhibition effectiveness.

Various ionic liquids (ILs) were tested as CH4 hydrate inhibitors with/without polymeric hydrate inhibitor, PVCap. Equilibrium dissociation conditions for CH4 hydrate were measured by the isochoric method in the presence of 10 wt% of ILs and they moved towards inhibition region as much as 1.4–1.8 K. Induction times of CH4 hydrate formation were also measured in the presence of the individual ILs at various concentrations, and of the mixtures of PVCap and ILs. Some ILs showed better CH4 hydrate inhibition behaviour than did PVCap. The mixtures of PVCap and several ILs exhibited enhanced kinetic inhibition effects for CH4 hydrate formation.

Figure optionsDownload as PowerPoint slide