Two-Stage De-Oiling Testing for Qualification with MEG Presence

摘要

Chevron Energy Technology Company performed a flow loop qualification under realistic conditions for arntwo-stage de-oiling unit in order to test the performance and robustness, especially for subsea developments.rnThe objectives of this qualification were to investigate the effects of both high pressure and the presence ofrnmono-ethylene glycol (MEG), under as realistic conditions as possible, on the system performance usingrncrude oil and water. MEG is a gas hydrate inhibitor which will likely be injected in long subsea tie-backs.rnThe tested compact produced water treatment system consisted of a two-stage de-oiling arrangement inrnwhich the first stage was a bulk de-oiler hydrocyclone, and the second stage was a polishing hydrocyclone.rnEach stage consisted of a pressure vessel which was filled with multiple hydrocyclone liners. For thisrnqualification, Sulzer's MixedFlow De-Oiling Liquid-Liquid Hydrocyclone technology was used. Sulzerrnhydrocyclones utilize a design with multiple openings in the inlet as well as a swirl generation element,rnresulting in a stabilizing and coalescing effect on the oil-water flow. The system was tested at a high pressurerntest loop with crude and methane to provide the most realistic testing conditions. Tests were also performedrnwith MEG in the feed. MEG is required for gas hydrate inhibition, and under some operating conditionsrnMEG can influence de-oiling efficiency during produced water treatment. For this reason, test points withrnand without MEG present in the feed were included in the test matrix.