Cold Model And Numeric Simulation Study On The Spouted-fluidized Characteristics Of Particles Of Cement Raw Material

The technique of the fluidization calcinations of clinker has been investigated for decades, yet there has not been any industrialized application until now. The latest successfully research is reached by Japanese scientists, and the pilot-plant has been experimented . On the other hand , there is not enough research on the pre-balling-fluidization calcinations of clinker presently, and valuable references on this subject available are very few, so it's worthy of further study on this subject.Years of study on fluidization calcinations of clinker with particle diameter above 5mm in traditional fluidized beds has been made by our research team. In this paper we continue the work by some experiment and numeric simulation on another fluidization operation system-spouted beds.Experiments indicate that for both quadrate bed and cylinder-conical bed with the ratio between the inlet diameter and the contactor bottom diameter Di/D0 =1.0 the spouting of the particles will strictly experience five stages while increasing air velocity from zero to several time of minimum spouting velocity : fixed bed, upper shift of the whole packing material, inner fluidization, steady spouting and jet spouting; inner spouting will appear right after the steady spouting while decreasing the air velocity and the pressure drop and its fluctuation is much lower than those in the steady stage. Inner spouting can have at the same time the merits of moving bed and spouted bed and therefore is worthy of further studying for prohibit application in industry.It is hard to achieve steady spouting for the particles of dp=8.27mm undercurrent conditions: with small stagnated bed height, spouting pressure will drop with the increasing of air velocity right after the formation of spouting and the particles are in the transition stage towards jet-spouting; the steady spouting can be formed while the stagnated bed height is higher than 14.0cm.For all the bed parameters, the maximum pressure drop(Pm) and minimum spouting velocity( U m ) in quadrate spouted beds are much higher comparing with the cylinder-conical beds. Pm in the quadrate spouted beds is 962Pa higher than that incylinder-conical beds with the same stagnated bed height, while spouting pressures are basically equivalent. Empirical formula for Pm in the quadrate spouted beds was fitted from experiment datum. Residual analysis shows the formula is better than the one formed by Muthur when calculating Pm in the quadrate spouted beds.CFD-DPM two way coupling method was introduced to simulate the spouting of particles in cylindrical beds and cylinder-conical beds. Simulation results show that DPM method has high reliability when simulating particles' movement in spouted beds. Porosity distribution, spout diameter and velocity profile in spout calculated are accordance with experimental results gained by San. Jose M J. The result of gas phase is not so satisfying because of the simplification of computational mesh and gas-solid coupling, so there is much work to do to perfect the CFD-DPM two way coupling method.