Experimental Study On Separation Performance And Flow Field Simulation Of New Dewatering Hydrocyclone

The salt contained in the light oil produced by atmospheric and vacuum refining will affect the quality of light oil products,cause corrosion,and damage the storage,transportation and process equipments.Adding the desalting water into light oil products and then using the dewatering hydrocyclone to separate water from oil can purify the light oil products.In the traditional dewatering hydrocyclone centrifugal force cause swirl to achieve phase separation,the difficulties,however,are incomplete separation due to close density for oil and water.In this paper,aiming to this problem,a cylinder is arranged under the underflow to improve separation performance of the hydrocyclone by increasing the settling time.After that,the mixture of white oil and water is used as the experimental medium to test the performance of the traditional hydrocyclone and the new one,as so to verify the rationality of the new structure.Numerical simulations are processed to investigate the internal flow field with different operating conditions and structural parameters of the new hydrocyclone.The dynamics of the flow for tradional and new hydrocyclone are evaluated to gain the reasons what the new one improved performance.The details are as follows:(1)The experimental results show that the separation efficiency of the new cyclone is better than that of the baseline one in low flow range,and the pressure drop is smaller.All of these are opposite in high flow range.(2)The simulation and experimental data of bottom flow pressure drop and overflow pressure drop are used to compare between the new cyclone and the reference one,which verifies the validity of the selected simulation method and turbulence model.The simulation results show that the tangential velocity,axial velocity,radial velocity,and turbulent kinetic energy evolution trend in the large cone,small cone,and straight tube sections of the new structure are agreed with the reference structure.Moreover,the flow field stability and uniformity is better.This indicates that the settling section of the new cyclone is more advantageous on separation.(3)With numerical simulation,the pressure distribution in the overflow,large cone,small cone,and straight pipe sections are studied.The results show that under the same conditions,the pressures at the overflow line,cone section and straight section of the new one are lower than those of the reference cyclone,indicating that the new structure causes more pressure drop.(4)By comparing the pressure gradient distribution cloud diagrams of the new and baseline cyclones at the same flow rate,it is found that the pressure gradient along the radial direction is basically the same.Both of them create a negative pressure zone in the swirl chamber near the end of the overflow tube.But the area is larger in the new cyclone,indicating it is more suitable to drive lighter mass to the overflow outlet.(5)The oil concentration distribution curves of the new type and the reference type are achieved for comparative study.It was found that the oil concentration in the bottom flow tube section of the new type is lower when the flow rate is small.