Kinetic Modeling of Methane Hydrate Formation in the Presence of Low‐Dosage Water‐Soluble Ionic Liquids

Abstract

The kinetic and thermodynamic effects of three typical low‐dosage imidazolium‐based ionic liquids (ILs) on methane hydrate formation and dissociation were investigated, considering the anion nature and subcooling and/or overpressure driving forces. Isochoric hydrate formation and dissociation data were obtained by the modified slow step‐heating method. ILs proved to have a dual effect on both formation and dissociation of methane hydrate including thermodynamic and kinetic inhibition. Kinetic modeling of methane hydrate inhibition by low‐dosage ILs was performed. Kinetic analysis showed that IL inhibitors mainly cause a delay in the nucleation or hydrate growth step. The related inhibition mechanism was resolved regarding the ionic nature and electrostatic interactions of ILs with water molecules. Two binomial exponential kinetic relations were derived and used for simple methane hydrate formation in the presence of ILs as kinetic hydrate inhibitors. The proposed relations can serve for a quick estimation of the nature, extent, strength, and effectiveness of ILs on various gas hydrates.

An experimental study of the synergistic effects of BMIM-BF4, BMIM-DCA and TEACl aqueous solutions on methane hydrate formation

“…Kim et al (2011) investigated the impact of ILs with pyrrolidinium-based cations on methane hydrate formation, and they observed both thermodynamic and kinetic inhibition effects of ILs. Nazari et al (2013) studied thermodynamic and kinetic effects of three ILs with imidazolium-based cations on methane hydrate formation. They also presented kinetic modeling of methane hydrate inhibition on the basis of IL nature and electrostatic intermolecular interactions between water and ILs (Nazari et al 2013).…”

“…Nazari et al (2013) studied thermodynamic and kinetic effects of three ILs with imidazolium-based cations on methane hydrate formation. They also presented kinetic modeling of methane hydrate inhibition on the basis of IL nature and electrostatic intermolecular interactions between water and ILs (Nazari et al 2013). Kang et al (2013) applied a mixture of ILs and polymer inhibitors and observed a synergistic effect on methane hydrate inhibition.…”

Pre-Screening of Ionic Liquids as Gas Hydrate Inhibitor via Application of COSMO-RS for Methane Hydrate

“…Muhammad Saad Khan 1,2 properties of IL-hydrate system. Simulation of COSMO-RS in calculating fundamental properties paired with the correlation developed in this work could now serve as a prescreening tool of ILs inhibition ability.…”

“…Gas hydrates are icelike crystalline solid compounds that could form in the presence of water and gas under favorable thermodynamic temperature-pressure condition [1]. At low-temperature and high-pressure conditions, water molecules (host) will surround the gas molecules (guest) and encapsulate the gas in a hydrogenbonded solid lattice [2]. Depending on the gases trapped, different structures of gas hydrates can be formed.…”

“…The results showed that IL is not only able to shift the hydrate thermodynamic equilibrium curve, but it also retards the formation of the hydrate. Since then, numerous experimental works have been carried out to study the effect of ILs in inhibiting gas hydrates formation, mainly using imidazolium-and pyridinium-based ILs [2,3,25,32]. The targeted ILs of this context are ammonium-based ILs (AILs), which are cheaper and easier to synthesis, but not being studied intensively.…”