MITIGATION OF METHANE HYDRATE BLOCKAGE IN SUBSEA PIPELINES USING IONIC LIQUID AS HYDRATE INHIBITOR

Abstract

Gas hydrates one of a major problem in the oil and gas industry. Formation of gas hydrates causes flow assurance issues as it can plug the pipeline. The use of chemical inhibitors; kinetic hydrate inhibitors and thermodynamic hydrate inhibitors is one of the most feasible ways to solve this problem. However, the problem with thermodynamic inhibitors is that it required in a large dosage and cause environmental issues. Thus, this study emphasises on the usage of ionic liquid as an effective kinetic hydrate inhibitor. The ionic liquid is a green chemical that can be fine-tuned explicitly as a hydrate inhibitor. The aim is to study the effectiveness of 1-Ethyl-3-Methylimidazolium Tetrafluoroborate (EMIMBF4), an ionic liquid as a kinetic hydrate inhibitor at various pressure and concentration. Micro Differential Scanning Calorimeter was used to measure the induction time of methane hydrate. The performance of ionic liquid was tested in different concentration and compared to the commercial kinetic hydrate inhibitor, Polyvinylpyrrolidone (PVP). From the experimental work, it was found that EMIMBF4 shows a dynamic inhibition effect as it can delay the induction time of hydrate. EMIMBF4 shows a higher induction time at a low concentration of 0.1wt%. At the pressure of 60 bar, the effectiveness of EMIMBF4 is comparable with PVP. However, PVP shows superior kinetic inhibition effect at the pressure of 40 bar. This study indicates that an effective, green hydrate inhibitor can be developed to counter hydrate formation problems in offshore subsea pipelines in a more cost-effective and environmentally friendly
 Keywords: Methane Hydrate; Hydrate Inhibitor; Ionic Liquid; EMIMBF4; Micro DSC; pipeline blockage