Strengthened oil-water separation by swirl vane hydrocyclone based on short-circuit flow regulation

Abstract

Hydrocyclones make it possible to separate oil/water efficiently. Short-circuit flow (SCF), which is a local secondary vortex in hydrocyclones, significantly restricts efficient separation. This study proposes a novel swirl vane hydrocyclone to regulate the trajectory of the SCF to reduce the SCF rate. The separation process in the hydrocyclone field is calculated using computational fluid dynamics coupled with the population balance modeling. The strengthened separation mechanism by the swirl vane is revealed, and the response of structural parameters, such as the angle, numbers, and width of the swirl vane, to the SCF rate and separation efficiency is investigated using the response surface optimization method. The results show that the swirl vane structure prevents the direct generation of SCF, strengthens the outward migration of the heavy-phase droplets, and reduces the probability of droplet breakage. The optimal structural parameters of the swirl vane are a swirl vane angle of 31°, vane number of 6 pcs, and vane width of 2 mm, which has the lowest SCF rate of 1.62 %. The separation efficiency increases by 21.53 %, and the SCF rate decreases by 85.33 % compared with a conventional hydrocyclone. This study provides theoretical guidance and data support for SCF regulation and the development of oil-water separation hydrocyclone.