Flow field analysis and performance evaluation of a hydrocyclone coalescer

Abstract

ABSTRACT Hydrocyclones are extensively applied in oil-water separation for fluid purification. However, it is difficult for a hydrocyclone to separate tiny oil droplets. Therefore, the coalescence of oil droplets plays an important role in enhancing the separation performance of hydrocyclone. In this study, an innovative hydrocyclone coalescer (HCC) was designed to enhance the separation of de-oiling hydrocyclone. The population balance model was carried out to simulate the distribution characteristic of oil droplet size in the HCC. High speed video was utilized to study the coalescence process qualitatively. Furthermore, an improved particle size analysis experimental system was designed to evaluate the coalescence performance quantitatively. The effects of inlet flow rate, oil concentration and water viscosity on the coalescence of oil droplets in HCC were analyzed. Results show that the optimum inlet flow is 3.9 m3/h, and the oil droplets with mean diameter 0–200 μm at the inlet of HCC can be enlarged to 502.54 μm at the outlet. When the viscosity of water increases from 1.03 mPa·s to 5.56 mPa·s, the mean diameter decreases from 502.5 μm to 382.4 μm. The HCC shows obvious coalescence performance under different operation and fluid parameters, which can contribute to enhancing the separation precision of hydrocyclones.