Numerical and experimental study on enhanced oil–water separation performance using hydrocyclone coupled with particles

Oil is one of the world's most crucial energy sources. In recent years, the separation of hydrocyclones coupled with multiphase or multifield has emerged as a leading trend in oilfield-produced fluid pre-separation technology. The study of complex dynamics among particles is crucial in multiphase-coupled separation systems. In this paper, we explore a novel separation approach: hydrocyclone separation coupled with particles to enhance oil–water separation, based on the composite force field. The computational fluid dynamics-discrete element method is utilized to analyze the dynamic behavior of particles and oil droplets within the coupling field, as well as the interactions among particles, oil droplets, and the flow field. Furthermore, the effects of operating parameters on the hydrocyclone coupled with particles (HCCP) and the conventional hydrocyclone (CHC) are compared through separation performance experiments. Results show that within a swirling flow field, the introduction of particles significantly exerts a pronounced influence on both the flow characteristics of the continuous-phase and the motion behavior of oil droplets. The coupling effect between particle movement and hydrocyclone separation is most pronounced when the density ratio of particles to oil ranges from 0.94 to 1. The separation performance experiments show that compared to CHC, HCCP can improve by 2.12–8.22 percentage points, and HCCP not only enhances separation efficiency but also exhibits wider applicability than CHC at lower inlet flow rates and split ratios. The numerical simulation results closely matched the experimental findings. This study may provide a reference for developing and applying hydrocyclones coupled with multiphase.