Structure Design And Performance Study On An Oil-water Separation Magnetic Hydrocyclone

The traditional oil-water separation hydrocyclone mainly uses the different centrifugal force between oil and water,which causes the different direction of the radial movement of oil droplets and water droplets to achieve rapid separation.However,with the gradual expansion of Oilfield Polymer Flooding,ASP flooding technology and other oil displacement technologies,the viscosity of produced fluid is increasing,and the emulsification is serious.The separation effect is greatly affected.Therefore,the concept of magnetic field is introduced into hydrocyclone.High efficiency separation of hydrocyclone under the coupling of centrifugal force field and magnetic field could be achieved,and a kind of magnetic-core hydrocyclone is designed.It is mainly composed of a cyclone and a magnetic core that is arranged by a number of coils in this cyclone.A magnetic field is provided by the coils which are arranged in a certain order in the magnetic core.The radial magnetic force pointed the center of the cyclone is applied to the solid magnetic particles in the hydrocyclone.Before separation,the solid magnetic particles with the same density and particle size as oil were added into the oil-water mixture,which is a kind of complex formed by wrapping the magnetic material with lipophilic polymer.During the separation process,magnetic particles are subjected to centrifugal force and magnetic force simultaneously,so they could "carry" or“push”oil droplets towards the center of the hydrocyclone through the contact and collision between magnetic particles and oil droplets,and ultimately achieve the efficient separation of oil and water.The separation principle of magnetic hydrocyclone and the interaction between magnetic particles and oil droplets are theoretically analyzed,and the force model of magnetic particles and oil droplets with or without magnetic field is established.The feasibility of improving separation efficiency by means of magnetic particles carrying or pushing oil droplets is theoretically determined.The PIV velocimetry test was carried out with fluid velocity as the object of analysis.The results show that the simulation results of velocity cloud image,vector graph and velocity variation curve along Y axis are in good agreement with the test results.And by this way,the reliability of the simulation is verified to some extent.Then the numerical simulation of the coupling of centrifugal force and magnetic field is carried out on the basis of theoretical calculation.The simulation results show that whether the magnetic particles are affected by magnetic force and the magnitude of magnetic force have a significant impact on the separation performance of hydrocyclone,It is concluded that the magnetic force of the magnetic particles is 7.5×10^-8N when the hydrocyclone has the best separation performance.The initial efficiency was 75.1%,and the efficiency was increased to98.1%after adding magnetic particles,when the operating parameters of the hydrocyclone are optimized,it is found that the separation effect is better when the processing capacity is4m³×h^-15m³×h^-1;When the flow ratio F is about 0.3,the magnetic hydrocyclone with this structure has higher separation efficiency,in addition,at this time,the concentration of overflow oil phase is relatively high.Through the PIV velocimetry test and numerical simulation,it was found that the magnetic-core hydrocyclone can obviously improve the oil-water separation effect.It also provides a new idea for the separation method and structure design in oil-water hydrocyclone.