An Investigation Into Fragmentation And Granulation Of Raw Balls In A Clinker Calcinations System With Fluidized Bed Of Coarse Particle

A kind of new equipment for clinker calcinations has been developed with fluidized bed of coarse particle to overcome some shortcomings in the traditional processes. It has been proved that the new method was basically successfully by pilot experiment, however, there were still a lot of problem not to be solved. So emphasis of this project was located on the investigation of fragmentation and granulation phenomenon of raw particles in the system so that more reasonable operation parameters can be acquired. Main results showed as follow:By testing relatively parameters of raw ball in different zone of system, fragmentation mechanism was analyzed as below: In the preheating zone of the system, three reasons result in raw ball fragmentation, i.e. thermal stress of resulted from temperature gradient in raw ball inner, water gas explosion of internal raw meal, and emit of internal water and gas product toward outer. In both spouted bed and fluidized bed, the fragmentation of particle is caused by friction among particles.From the viewpoint to prevent fragmentation of raw ball, appropriate operation parameters in above three zones are determined under different operating conditions. It is shown that the temperature in the preheating zone should not be over 420℃ and particles retention time should be control in the range from 200s to 300s. In the spouted bed, suitable granules diameter should be controlled in the range from 4mm to 7mm, with superficial gas velocity from 1.3¹.6u_ms and H₀/D<2.On the basis of theoretical analysis, the experiment research about cohesion phenomena among raw ball in high temperature was carried out. The result showed thatliquid bridge force among raw ball is critical factor which result in particle cohesion. The higher the temperature is, the more the liquid bridge is prone to formed. The neck length of liquid bridge between raw balls continuously increases with time as well as the cohesive force.From the experimental results, the optimum craft and operation parameter are provided for future hot model experiment. Through analyzing the influence of cohesion on the fluidized state of raw material in fluidized bed, the measure are brought forward to be used to release the cohesion phenomena happened in the high temperature fluidized bed and protect from dead bed of fluidized bed.From the experimental results, the optimum craft and operation parameters are provided for future hot model experiment.