Résumé
A critical aspect of operating an oil well consists of separating oil from the water that is jointly produced. This paper describes modeling of a crossflow filtration hydrocyclone (CFFH), a device that combines desirable attributes of a crossflow filter and a vortex separator into one unit to separate oil from produced water. A porous media is incorporated around the crossflow outlet region of the cylindrical CFFH so as to achieve the desired separation efficiency. The main purpose of this work is to predict the fluid dynamic behavior of a particular CFFH design and its separation efficacy based on 3D computational fluid dynamics (CFD) simulations. The velocity field in the fluid phase is obtained using a Reynolds Stress Model (RSM) for closing the Reynolds Average Navier-Stokes (RANS) equation. The Lagrangian Discrete Phase Model (DPM) is used to investigate the trajectories of particles mimicking oil droplets and grade efficiency of the CFFH. The effect of the Reynolds and the Stokes numbers on the grade efficiency and particle residence time is studied. The effective length of the porous media and the vortex strength for different operating conditions is also investigated. Results indicate that the separation efficiency is significantly influenced by the porous media. Hydrocyclones with an aspect ratio greater than 4.0 exhibit lower grade efficiency due to a weaker swirl.