Study On The Influence Of Spiral Structure Of Decanter Centrifuge On Oil Sand Separation Performance

The main particle size of sand in some oil fields is less than 100μm,which requires the development of sand removal devices for small particle size separation.Through literature research and field application analysis,decanter centrifuge has the ability to separate small particle size in the convection body,and the separation efficiency is high,and the sand removal condition is stable.At present,most studies on decanter centrifuge focus on the external rotating drum of centrifuge,while studies on the internal spiral of centrifuge are not systematic enough,and only single factor analysis is carried out.In this paper,the optimization of the spiral structure of decanter centrifuge used for oil sand separation is systematically studied,and the optimization structure model is selected.In this paper,the centrifugal force field,fluid flow law and solid phase deposition method in decanter centrifuge are studied by theoretical research.By establishing the three-dimensional model of decanter centrifuge,the flow field and solid phase deposition law of decanter centrifuge were analyzed by numerical simulation method,and the influence law of feed chamber and pitch on the separation efficiency of decanter centrifuge was analyzed,and the optimal design of spiral structure was carried out based on this law.In addition,the application conditions of the optimized decanter centrifuge are also explored,which provides scientific basis for the design and optimization of solid-liquid separation device.The main conclusions of this paper are as follows:(1)The distribution law of velocity field and solid phase deposition in decanter centrifuge was studied by numerical simulation method,as well as the basic principle of using spiral for separation and solid phase pushing,and the main factors affecting the separation efficiency of spiral structure were identified as pitch and outlet width of feed chamber.(2)Different pitch and outlet width of the feed chamber were selected for numerical simulation.By changing a single variable,it was found that the separation efficiency increased first and then decreased with the increase of pitch,and the separation efficiency also increased first and then decreased with the increase of outlet width of the feed chamber.(3)Response surface analysis was used to design experiments on the interaction between the two factors on the separation efficiency.The width and pitch of the inlet cavity were taken as constraints,and the separation efficiency was taken as the objective function for numerical simulation experiments.Through the analysis of the results of 13 groups of experiments,when the pitch parameter is 112mm and the inlet cavity outlet width is 102mm,the separation efficiency is increased by about 9%on the basis of the initial model.(4)By changing the operating parameters,the adaptability of the selected optimized structure was analyzed,and the influence of the inlet solid volume fraction and processing capacity on the separation efficiency was studied by using the control variable method.The results show that the separation efficiency gradually decreases with the increase of the imported solid phase volume fraction,and rises first and then decreases with the increase of the treatment volume.Better results can be achieved when the treatment volume is less than 22m~3/h and the imported solid phase volume fraction is less than 37%.