Separation Performance Study Of Built-in Diversion Cylinder Cyclone Clarifier

With the acceleration and deepening of coal mining,new features such as high suspended solids content,fine particle size and light specific gravityhas has gradually exhibited in mine wastewater which increased the equipment load during the treatment process and operating costs.For such problems,the paper proposes a new technology of mine water treatment by means of "static mixer plus built-in diversion cylinder cyclone clarifier".In the treatment process,the heavy medium(fine sand)is used to enhance the specific gravity and strength of the flocs,aiming to promote the rapid sedimentation and separation of mud from clear water under the action of the centrifugal force field and gravity field inside the built-in diversion cylinder cyclone clarifier.By using theoretical analysis and numerical simulation methods,the paper investigates the interaction rule between the flow field characteristics and particle motion,By carrying out settlement separation experiments,the paper explores the influence of operating parameters and structural parameters on the separation performance.The research can improve the cyclone separation theory and guide the industrial application of built-in diversion cylinder cyclone clarifier.Based on the coagulation kinetics theory,cyclone separation theory and other theories,the calculation method of the structural parameters of the built-in diversion cylinder device is deduced.The equation of fluid motion in the spiral flow clarifier is established.The compound force fields acting on the fine sand flocs are analyzed and the particle size distribution law in the flocculation zone is obtained.The software of Fluent is used to numerically simulate the flow field inside the clarifier.The influence law of inlet velocity,outer diameter of built-in diversion cylinder,insertion depth of built-in diversion cylinder and inclination angle of built-in diversion cylinder on the fluid velocity,turbulent kinetic energy and turbulent kinetic energy dissipation rate in the flow field are comprehensively analyzed.The results show that increasing the inlet velocity can increase the initial shear strength,which is conducive to flocculation.Appropriately increasing the insertion depth can extend the hydraulic distance,which is beneficial to floc growth.Appropriately reducing the inclination angle can increase the speed gradient difference and avoid the breaking of large flocs.Properly increasing the outer diameter can increase the initial velocity gradient,which is conducive to flocculation.The optimal parameter combination after comprehensive analysis is that:The inlet speed is 0.93m/s,the insertion depth is 50mm,the inclination angle is 2°,and the outer diameter is 180mm.The separation performance of the Built-in diversion tube cyclone clarifier was studied through the experiment,and the comparative test was conducted on the presence and absence of the built-in diversion cylinder in the cyclone clarifier.The effects of different operating parameters and structural parameters on separation performance were analyzed by single factor experiment,and the optimal parameter combination was obtained by orthogonal experiment on the more important parameters.The test results show that the treatment performance of the Built-in diversion tube cyclone clarifier is obviously improved compared with that of the common cyclone clarifier.The SS(Suspended matter)is stable below 50mg/L,and the removal rate of suspended solids is stable above 95%.Increasing the inlet speed properly is conducive to improving the effluent quality,but the excessive inlet speed will damage the flocs.With the increase of inclination angle,outer diameter and insertion depth,the quality of overflow effluent shows a trend of decreasing first and then increasing.With the increase of cylinder height,the quality of overflow effluent tends to decrease first and then stabilize.Through the orthogonal test,when the inlet speed is 0.93 M/s,the outer diameter is 180 mm,the insertion depth is 50 mm,and the inclination angle is 2°,SS(Suspended matter)can be reduced to 36.2 mg/L,turbidity can be reduced to 7.7 NTU,and the number of overflow particles is 12010/ml.The primary and secondary order affecting the separation performance of clarifier is:inlet speed>outer diameter>inclination angle>insertion depth.On the basis of theory and experimental research,an industrial experimental study is conducted for the waste water with its yield up to 1000mg/L in a mine in Ningxia.The clarification system is expected to treat 5m3/h.The operation results show that the effluent SS(Suspended matter)is stablely below 10mg/L and the underflow concentration exceeds 10%,achieving the goal of efficient treatment of mine wastewater and rapid recovery of sediment,which can also provides a design basis for the design and analog amplification of the efficient mine water treatment system.