Numerical Simulation for a CFB Boiler’s Cyclone Separator with Structure Optimizations

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In the circulating fluidized bed (CFB) boilers, the cyclone separator is a critical component of the external solid recycle loop. It is used to separate solid particles from flue gas efficiently. In this paper, numerical simulations are conducted to study the dependence of cyclone separation efficiency on the configurations of separator entrance and central cylinder. The RSM turbulence model is adopted to describe the gas phase, and the particle stochastic trajectory model is used to describe the solid phase. The results show that the separation efficiency of the cyclone can be improved at a certain entrance section angle. When the inclination α = 10°, the separation efficiency of the cyclone is highest. When the entryway has the ladder configuration, the streamlines in the cyclone separator tend to bend downward after passing through the ladder, which is conducive to improve the particles’ separation efficiency. A proper cutting angle at the bottom of the central cylinder can improve the internal gas flow and increase the separation efficiency of the cyclone separators.