A down-exhaust cyclone separator

In this paper we report on the development of a down-exhaust cyclone separa tor suitable for use as a primary device for gas-particle separation in cir culating fluidized-bed (CFB) boilers. It consists of a cylindrical shell wh ich is joined by an inclined cone, a guide body, and a downward exhaust pip e. The principle of solids separation is similar to that in reverse flow cy clones, except that in this separator the gas leaves the separator axially at the bottom. It has been shown that this separator is capable of achievin g a separation efficiency of around 99% in handling high solids loadings su ch as those in CFB boilers, at a pressure drop of around 400 Pa. A model ba sed on the mechanism of radial solids mixing is proposed, which assumes tha t the slip between gas and particles in the tangential direction is negligi ble and that the particles are well-dispersed. This model enables predictio n of grade separation efficiency, total separation efficiency, and cut diam eter. It may be used in conjunction with a pressure drop model to optimize the design and operating parameters.