Investigation of velocity field and oil distribution in an oil–water hydrocyclone using a particle dynamics analyzer

Abstract

A non-intrusive particle dynamics analyzer (PDA) was used to investigate the distribution of velocity field and oil droplets in a 50 mm oil–water separation hydrocyclone. Axi-asymmetry distribution of the flow field was observed in the hydrocyclone, which was perhaps attributed to the use of single tangential inlet in the hydrocyclone. The average size of oil droplets decreased from 43–126 μm at Z = 0 mm (the top) to 19–21 μm at Z = 990 mm (the bottom) at an inlet flow rate of 2000 L/h and flow rejection ratio of 20%. The average size of oil droplets at Z = 990 mm decreased from approximately 40–20 μm with the increase of flow rate from 1300 to 2000 L/h, showing the important impacts of the inlet flow rate on the removal of small oil droplets by the hydrocyclone. The concentration distribution of oil droplets in the upper cylindrical sections was characterized by the existence of a “concentration valley” surrounding the oil core. The “concentration valley” disappeared from Z = 590 mm. Results show that PDA is a powerful instrument for the characterization of oil–water separation hydrocyclones because it can present the velocity field and the distribution of oil droplets in the hydrocyclone simultaneously.