SIMULATION OF COMBINED FLUIDIZED BED FOR PRODUCING TITANIUM TETRACHLORIDE
In this paper, a model is developed to describe the behavior of combined fluidized bed for producing titanium tetrachloride.The combined fluidized bed, which consists of a riser and a turbulent bed at least, is an innovative reactor and can be used as the reactor of gas-solid reaction to avoid agglomeration and enhance mass and heat transfer rate.In this model, a one-dimensional model with axial dispersion is used to describe turbulent bed, and particle size distribution is determined by a population balance model.It is found that coke can not burn to provide heat unless the temperature exceeds the autogenous ignition temperature (about 873 K).High-grade titania feedstock is mainly chloridized in the turbulent bed.Furthermore, a rise of the initial concentration of oxygen can increase the conversion of high-grade titania feedstock, but this increase tends to level off when the initial concentration of oxygen is higher than 3.0 mol·m -3 .There is an infeasible operating area where the heat balance of reactor can not be achieved between 973 K and 1373 K when the initial concentration of oxygen and chlorine is lower than a certain value.