Ionic Liquid as Low Dosage Hydrate Inhibitor for Flow Assurance in Pipeline

1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM BF4) was explored in carbon dioxide (CO2) gas mixture for its potential application as gas hydrate inhibitors for CO2 hydrate (Type I). Induction time was the parameter obtained using High Pressure Kinetics Measurement (HPKM) for a bulk volume of 130 mL. The temperature for all the experiments was kept constant at 275.0 K (2°C) with the pressure varied at 25, 30 and 35 bar. The ionic liquid was tested as a kinetic inhibitor as well as thermodynamic inhibitor. In practice, kinetic inhibitors are typically used at concentrations of 1 wt.% or less, thus, the experiment was conducted for three different concentrations of the ionic liquid; 0.1, 0.5 and 1.0 wt.% at varying pressures. EMIM BF4 at a concentration of 10.0 wt.% was also tested but at 30 bar only to study the effectiveness of ionic liquid as thermodynamic inhibitors. It was found that the induction time for CO2 hydrate formation increases in the presence of more highly concentrated ionic liquid. However, at high concentration of 10.0 wt.%, EMIM BF4 does not show significant changes in the induction time as CO2 hydrate inhibitor.