Research on strong swirl turbulent desorption technology of oily sludge

Abstract

Oily sludge is a solid waste generated in the process of oil exploitation, processing and gathering and transportation, and its effective treatment and utilization is one of the key problems to be solved in the field of petroleum and petrochemical. This study investigates a reduction pretreatment method for oily sludge based on intense turbulent detachment and liquid-liquid strong swirling separation technology, supplemented by laboratory-scale feasibility experiments. Numerical simulations of the single-phase flow field within the hydrocyclone were conducted using Fluent software. The results indicate that the shear effects in the swirling flow field provide a favorable environment for the detachment of oil from sludge. Through phase trajectory and particle behavior analysis, the motion state and detachment-separation process of oily sludge particles of different sizes were examined. It was found that particles undergo both viscous shear stress and Reynolds shear stress, with oil detachment achieved through mechanisms such as particle collision and friction. Laboratory experiments were conducted utilizing an axial-flow hydrocyclone to validate the process and determine the optimal structural and operational parameters for the single-tube cyclonic separator. Under the conditions of flow rate of 3.5–4m³/h, overflow ratio of 12 %, water mixing ratio of 1:10 and chemical concentration of 100 mg/L, the recovery rate of crude oil at the bottom of the treatment tank can reach 83.93 %, the pressure is reduced to 0.2 MPa, the residue content of the oil phase is less than 0.5 %, and the oil content of the oil sludge (water) after separation is < 5000 mg/, indicating that the turbulent action of the swirl field can realize the desorption of oily sludge and is expected to be applied to engineering practice.