Based on NO_x emission reduction principle using deep air staging combustion technology

the center cylinder of a cyclone separator is changed into sleeve form

and the ‘top wind' is introduced into the top of the sleeve as supplemental air

which is to reduce the NO_x emission. The effect of the ‘top wind' on separation efficiency of the cyclone separator is investigated. The results show that

by introducing the ‘top wind'

the pressure drop of the cyclone increases. At the optimum speed of the ‘top wind'

the separation efficiency of the particles with size smaller than 1.5 μm can be increased by about 10%. When the insertion depth of the sleeve(vortex finder) is increased from 10 mm to 45 mm

the particle separation efficiency increases at first and then decreases

and the optimum top wind speed decreases from 30 m/s to 10/20 m/s. When the size of the sleeve(vortex finder) is reduced to 1 mm

the pressure drop between the inlet and the outlet decreases by about 57%

and the optimum speed of the top wind is still kept at 10～20 m/s.