Study On Effect Of Solid Particles On Oil-water Separation Performance Of Hydrocyclone

Nowadays,the water content of the produced fluid produced in the later stage of oil field is more and more high,and the oil displacement methods such as tertiary oil recovery are more and more widely used.It is more and more difficult to separate the produced fluid with the existing hydrocyclone only relying on centrifugal force.Based on the hydrocyclone separation method,a multi-phase coupling separation method is proposed,in which a third-phase medium is added to the oil-water mixture.During the movement of solid particles in the hydrocyclone,part of the oil drops are pushed to increase the radial and axial forces on the oil drops,so as to promote the oil-water separation and improve the separation performance of the hydrocyclone.Based on the Eulerian-Eulerian method,the discrete phase model(DPM)model is used to simulate the distribution of solid particles,the volume distribution of oil phase,the pressure loss,the velocity field,the characteristics of operation trajectory and the separation efficiency in the hydrocyclone under the conditions of different physical parameters of solid particles and operating parameters of hydrocyclone.The flow field in the hydrocyclone under the condition of multiphase coupling separation and conventional centrifugal separation was simulated and compared.The results show that the solid particles can carry or push the oil droplets in the separation process,improve the oil-water separation efficiency,and maximize the separation efficiency of the hydrocyclone2.88%.Under the condition of different physical parameters of solid particles,the single variable method is used to analyze the distribution and migration path of solid particles,the residence time of solid particles,axial,tangential and radial velocity,oil phase distribution,pressure loss and separation efficiency in hydrocyclone.The best physical parameters of solid particles are obtained as follows:the injection quantity of inlet surface is 2000,and the density of solid particles is 770 kg/m~3,solid particle size 0.3 mm,at this time,the coupling effect of solid particles and oil drops is better,which has the greatest promoting effect on oil-water separation,and the oil-water separation efficiency is 96.05%.By comparing the effects of the changes of the physical parameters of different solid particles on the separation performance of multiphase coupling,the following rules are obtained:under the changes of the physical parameters of different solid particles,the separation efficiency of multiphase coupling presents the trend of increasing first and then decreasing,and the injection amount and particle size continue to increase,the separation efficiency of multiphase coupling tends to be gentle,while the increase of the density of solid particles leads to the obvious separation efficiency of multiphase coupling down.The numerical simulation of the hydrocyclone is carried out under the condition of multi-phase coupling.Taking the operating parameters as the optimization object,the optimal operating parameters range of the hydrocyclone is selected by analyzing the distribution and migration path of solid particles,the distribution of oil phase,the distribution of velocity,the pressure loss and the separation efficiency.The optimal range of operation parameters is:processing capacity 4.25 m~3/h?5.25 m~3/h,overflow diversion ratio 0.25?0.35,oil content at the inlet 0.01?0.04,droplet size 0.2 mm?0.3 mm.By analyzing the influence of different operation parameters on the efficiency of multiphase coupling separation,it is found that the change of multiphase coupling separation efficiency is positively related to the treatment capacity,split ratio and oil droplet size,and negatively related to the volume fraction of oil.The oil droplet size has the greatest impact on the multiphase coupling separation,and the range of separation efficiency change reaches to 29.43%.