入口收缩角度对旋风分离器分离性能的影响

Influence of inlet necking angle on separation performance of cyclone separator

入口收缩角度对旋风分离器内流场及分离性能有着重要影响,从而影响循环流化床(CFB)机组的运行性能。本文以临清三和280 t/h CFB锅炉的旋风分离器为例,采用数值模拟的方法对入口收缩角度α为14°、20°、25°、30°、34°这5种旋风分离器进行研究。结果表明:当烟气流量恒定时,入口收缩角度越大,切向速度越大,颗粒所受到的离心力也越大;轴向速度的下行流速度也越来越大而上行流速度越来越小;分离器的压降越来越高,而分离效率先逐渐升高后逐渐下降。进一步研究收缩角度和缩口速度对分离效率的影响,收缩角度和缩口速度都存在优化值,在本研究范围内,该型旋风分离器收缩角度和缩口速度的优化值分别为30°、20 m/s。

The inlet necking angle has an important influence on flow field and separation performance of cyclone separator,thus affecting the operation performance of circulating fluidized bed(CFB)units.By taking the cyclone separator equipment of Linqingsanhe 280 t/h full-scale CFB boiler as the example,the numerical simulation of five cyclone separators with inlet necking angle of 14°,20°,25°,30°and 34°is carried out.The results show that,with a constant flue gas flow and as the inlet necking angle is increased,the tangential velocity and the centrifugal force on the particles increase,the downstream velocity of axial velocity increases while the upstream velocity decreases,the pressure drop of the cyclone separator rises while the separation efficiency increases at first and then decreases.The effect of the necking angle and necking velocity on the separation efficiency is further studied,and it shows that there are optimum values for both necking angle and necking velocity.Within the scope of this study,the optimum values of the necking angle and necking velocity of the cyclone separator are 30°and 20 m/s,respectively.