Numerical Simulation Of Structural Parameters Optimization Of Cyclone Separator

Cyclone separator is a core equipment of circulating fluidized bed boiler.Its separation efficiency has a direct impact on the operation of circulating fluidized bed unit.Taking cyclone separator equipment of Linqingsanhe 280t/h full-scale circulating fluidized bed boilers as examples,the effects of the flow field and separation performance of cyclone separator inlet structure parameters,exhaust pipe structure parameters,cylinder-cone structure parameters and exhaust dust structure parameters were researched by using fluid simulation software.Finally,the effects of inlet structural parameters,exhaust pipe structural parameters,cone structural parameters and dust exhaust structural parameters on the velocity field,pressure field,pressure drop and separation efficiency of cyclone separator were explained and the optimum values of the parameters were obtained.The main results were as follows:(1)The effect of inlet structure parameters(including inlet necking angle and inlet height-width ratio)on the flow field and separation performance of cyclone separator were studied.The results shown that: the tangential velocity and the pressure drop of separator were raised while the separation efficiency was increased first and then decreased by increasing inlet necking angle gradually.Similarly,the tangential velocity and the pressure drop were raised when the inlet height-width ratio increased gradually.However,the separation efficiency did not be enhanced with the increase of the inlet aspect ratio.Within the scope of this study,the optimum inlet necking angle and inlet height-widthratio of the cyclone separator were 30° and 2:1,respectively.(2)The influence of structure parameters of exhaust pipe(including the diameter of exhaust pipe and the insertion depth of exhaust pipe)on the flow field and separation performance of cyclone separator were studied.The results shown that: when the diameter of exhaust pipe increased gradually,the tangential velocity and the pressure drop were descended while the separation efficiency was first increased and then decreased.Similarly,when the insertion depth of exhaust pipe raised gradually,the tangential velocity was dropped.Both pressure drop and separation efficiency were increased first and then decreased.Within the scope of this study,the optimum diameter of exhaust pipe and insertion depth of exhaust pipe were 0.35 D and 0.5a,respectively.(3)The influence of structural parameters of the cone(including the the height of cylinder and cone and the diameter of the cone tip)on the flow field and separation performance of cyclone separator were studied.The results shown that: the tangential velocity and pressure drop of cyclone separator were reduced by increasing the height of cylinder and cone,but the separation efficiency was not always increased or decreased with the rise of cylinder height or cone height.There was an appropriate range for the ratio of cylinder height to cone height.The pressure drop was decreased while the separation efficiency was increased first and then decreased when the diameter of cone tip enhance,Within the scope of this study,the optimum cone tip diameter was 1De.(4)The influence of structure parameters of exhaust dust(including four kinds of exhaust dust structure and straight pipe length)on the flow field and separation performance of cyclone separator were studied.The results shown that: increasing the straight pipe and ash hopper had a significant effect on improving the separation efficiency of cyclone separator.When the length of straight pipe increased,the tangential and the pressure drop were dropped slightly,while the separation efficiency was increased first and then decreased.Within the scope of this study,the optimum length of straight pipe was 2D.