Study On The Influence Of Gas Content Of Produced Liquid-solid On Hydrocyclone Separation

In the process of crude oil exploitation,not only the crude oil is flowing out with the produced fluid,but also a large amount of sand.The emergence of cyclone separator makes the sand phase can be separated out more easily and with higher efficiency.The liquid-solid hydrocyclone is extremely sensitive to the inclusion of gas in the operation process.Because the gas phase is special compared with liquid-solid phase,the influence of small gas content on the internal flow field of the hydrocyclone can not be ignored.The main research contents and conclusions of this paper are as follows:(1)The main diameter of the liquid-solid hydrocyclone was determined according to the treatment capacity,and other characteristic dimensions were further determined.After the size was determined,the model was established by Solid Works software,Mesh was divided by MESH software,and numerical simulation was conducted by Fluent software.(2)For liquid-solid swirling,the tangential velocity and the flow field have the greatest influence among the three velocity components.The tangential velocity and the flow field are distributed centrally and symmetrically inside the cyclone.The value is zero at the wall surface,and changes greatly near the wall surface,and is negative at the central axis,and changes greatly at sections of different heights.The static pressure value is larger than the dynamic pressure value,so the change trend of the total pressure is basically the same as the static pressure,and both of them are in a symmetrical distribution.The cross-section of different heights changes greatly.(3)In the three-phase simulation,compared with the two-phase simulation,the tangential velocity value increases somewhat,and the velocity value changes little at the same radial position and different height sections;The static pressure value increases more than that of the same radial position.The static pressure value of the section at different heights is basically the same.Near the axis,there appears an area with fixed pressure,which is the so-called negative pressure area.In terms of concentration,the gas phase is mainly concentrated near the axis,and the liquid-solid phase is more near the wall.(4)Under different gas holdup,the higher the gas content,the more the tangential velocity value increases,and the stronger the internal swirl effect;With the increase of gas content,the volume proportion of liquid concentration at the overflow outlet will decrease.The separation pressure drop of the cyclone decreases continuously with the increase of the gas content.(5)The influence of the gas holdup on the pressure drop of the cyclone was further explored,and the scatter diagram of the pressure drop variation under different gas holdup was drawn and fitted,and the prediction formula was obtained.The pressure drop could be predicted according to the gas holdup.The decrease of pressure drop will reduce the processing capacity,that is,the inlet speed will be reduced,and the further separation efficiency will also be reduced.The research content in this paper provides a great help for the further study of the internal flow field and separation characteristics of the liquid-solid cyclone with gas,and it can also provide some references for the on-site gas treatment process.