Deep Water Mitigation of Gas Hydrate Formation Using Alium Cepa Skin Extract (ACSE)

Abstract

Abstract The formation of Gas Hydrates is a major flow assurance challenge affecting the Oil and Gas Industry. Hydrates are ice-like, non-stoichiometric crystalline compounds formed at high pressures, and low temperatures usually in the presence of water as the ‘host’, and gases as the ‘guest’. When hydrates form, they tend to clog or plug the flowlines thereby, leading to flow restrictions. This study evaluates the performance of Allium Cepa Skin Extract (ACSE) in gas hydrate formation mitigation. Experiments were carried out using a locally fabricated High Pressure Magnetic Stirrer Autoclave equipment to compare the performance of ACSE to a conventional Kinetic Hydrate Inhibitor (PVP), and to ascertain the inhibitory capacity of the ACSE. For this experiment, Hydrate formation was detected by an increase in the temperature of the Reactor Cell and a drastic decrease in Pressure. The different weight percentages used were 0.01 wt%, 0.02 wt%, and 0.03 wt% respectively. Plots of Pressure, Temperature, and Time of the both inhibitors were made and results obtained were analysed. For the various concentrations (0.01-0.03 wt%) of ACSE, 0.02 wt%, and 0.03 wt% showed a higher inhibitory capacity compared to the PVP. For experiments with 0.01 wt% at the end of 120 minutes for PVP and ACSE, the final pressure drops were 12.3 bar, and 11.2 bar respectively. This shows that PVP was a better inhibitor than ACSE at that weight percentage. 0.02 wt% ASCE proved to be the most effective concentration in preventing gas hydrate formation because at this weight percent, the highest inhibitory capacity was obtained showing that increasing the dosage beyond this concentration would be uneconomical. Although for 0.01wt% which is the lowest concentration, PVP (pressure of 12.3 bar at the end of 120 minutes) performed better than ACSE (11.2 bar), the ACSE solves the challenge of environmental unfriendliness, toxicity, non-biodegradability, and availability. ACSE is eco-friendly, biodegradable, and locally available. Hence, it is recommended that it should be developed as an alternative to the toxic, and hydrate inhibitors used in the Oil and Gas Industry. Since the results of the experimental runs indicated that ACSE had a good performance, it therefore, implies that it may effectively inhibit hydrate when used for field trial.