Experimental Study On Performance Of De-watering Hydrocyclone In Light Oil Desalting Process

The light oil produced by atmospheric or vacuum distillation units in an oil refinery usually contains salts.In industry,these salts are dissolved by water and then separated from the light oil.A de-watering hydrocyclone is preferred to water-oil separation due to its simple structure,low cost and easy operation.However,the study about de-watering hydrocyclones is not enough.Little is known about the separation mechanism and the prediction of efficiency and pressure drop of de-watering hydrocyclones.In this paper,a 20 mm model of hydrocyclone is designed and fabricated.A test rig is designed and constructed to study the influence of geometrical and operational parameters on the separation performance.The test medium is mixture of white oil and clean water.The water content is 5% and the split ratio of underflow is 5%.The experimental data are analyzed by methods of single factor screening,orthogonal experiment and response surface respectively.The main conclusion are as follows:(1)The main structural factors which have great influence on the separation performance are the overflow tube diameter dof,vortex radius r,and underflow tube diameter duf.And the order of importance both for the efficiency and overflow pressure drop are dof,r and duf.The overflow tube diameter dof and vortex radius r has the greatest interaction on the separation efficiency of de-watering hydrocyclone.(2)Based on the response surface method,two mathematical formula about the separation efficiency and overflow pressure drop are deduced by regression of the experimental data.An optimized structure of de-watering hydrocyclone is also obtained,whose characteristic dimensions are dof =10mm,r=18 mm,duf =6mm,?=20°.(3)A proof test shows that when the capacity ranges from 0.5 to 2.5 m3/h,the separation efficiency of the optimized hydrocyclone is as high as 97.5%;the maximum overflow pressure drop is 0.23 MPa and the flow regulation ratio RQ is not less than 5.The error of the separation efficiency and overflow pressure drop between the experimental values and the predicted ones is only 0.4%.