Experimental research on enhanced the microfine oil droplets separation using hydrocyclone coupled with fiber coalescence

Abstract

The limitations of swirl separation in removing microfine oil droplets in water have driven the development of hydrocyclone technology coupled with multiphase or multifield techniques. To enhance microfine oil droplets separation, a novel hydrocyclone separation coupled with fiber coalescence (HCCFC) was designed. The interaction between fiber balls and oil droplets inside the hydrocyclone, including droplet coalescence and breakage, was investigated. The influence of different operating parameters on separation efficiency was discussed. The results showed that fiber balls promoted oil droplet coalescence when the inlet droplet size ($D_{43}$) was below 22.37 μm but caused droplet breakage above this threshold. The coalescence performance of HCCFC improved with increasing inlet oil content but declined beyond 450 mg·L⁻¹. Separation experiments confirmed that HCCFC outperformed conventional hydrocyclone, with separation efficiency increasing by 2.9% to 20.0%. As the fiber ball content and inlet flow rate increased, the separation efficiency showed a trend of first increasing and then decreasing. Additionally, HCCFC's separation efficiency varied with inlet oil droplet size distribution, showing the most significant enhancement when $D_{43}$ was 22.37 μm, where separation efficiency increased by 14.4%. These findings offer insights into the development and application of multiphase coupled with hydrocyclone technology.