CFD Study for a Novel Multi-Stage Flotation Column
WEN Xin1, LIU Chun-Jiang2
(1School of Chemical Engineering and Technology，Tianjin University，Tianjin 300072，China；
2State Key Laboratory of Chemical Engineering(Tianjin University)，Tianjin 300072，China)
Abstract：
Novel multi-stage flotation column was developed independently in our lab and computational fluid dynamics software FLUENT6.3.26 was used for numerical simulation of gas-liquid two-phase flow. Euler-Euler multiphase flow model was used to simulate gas phase with single gas bubble size. A standard k-ε turbulence model was used to describe two phases in the simulations, considering the drag force for interphase momentum transfer only. The liquid velocities, axial liquid velocities and gas holdup distribution in the different radial positions were obtained through the simulations. It was shown that increasing the gas velocity would improve the gas holdup and liquid circulation rate, which means the more sufficiently gas and liquid were mixed, the better effect of flotation would be. It is significant for improving the separation efficiency in the column and the scale-up of the column. Performance of multi-stage loop packed flotation column at different conditions was tested with coal slurry in Qianjiaying Kailuan Mining Company. Under gas velocity of 1.25 m3/h and feed of 0.05 L/h, with residence time of 20 min，coal ash was 10.28%, tail ash of 43.39%, clean coal yield of 52.53%. It was close to coal ash of 10.58% in this company.
2014, Vol. 31 
