Experimental Research On Separating Ultra Fine Particles From Oils By Mini-hydrocyclone

Ultra fine particles, like coke powder, catalyst, entrained in oils, has always been a difficult challenge restricting the long-term continuum steady operation of industrial plant at low cost. Three new-type mini-hydrocyclone fit for separating ultrafine particles, with 10 mm, 25 mm,50 mm cylindrical diameters respectively, was designed according to the research findings of scholars and the experience of engineering practice. The performances for separating coke powder from tap water and gas oil were tested by experiments, and inner two-phase flow field was simulated by computational fluid dynamics under the optimum experimental conditions. Primary conclusions are as follows.(1) When feed concentration is 200 mg/L, flow ratio of 10 mm,25 mm,50 mm mini-hydrocyclone is 17%,8%,8% respectively, the temperature of coke powder/tap water system and coke powder/gas oil system is respectively 45℃,60℃, the relationship model between Eu and Re of designed hydrocyclone geometry, the empirical model for predicting cut size and corresponding scale-up model were obtained, which could guide the separation system and scale-up design.(2) Under high efficiency work conditions, the efficiency of separating coke powder from tap water by 10 mm mini-hydr～cyclone is 80%～85%, cut size 4.6μm, and the efficiency of separating from gas oil is 58%-60%, cut size 7μm. we can choose these hydrocyclones according to separating demands in industrial application.(3) Simulate the optimum work conditions by RSM and DPM model, and simulated grade efficiency curves were obtained. The predicted cut size accorded with the experimental data, and the error of predicted separation efficiency is within 10%. The model can be used to predict separating performance and guide optimum design.