Abstract: 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 873K).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 973K and 1373K when the initial concentration of oxygen and chlorine is lower than a certain value.

摘要： 组合式流化床是一种将提升管和湍床串联使用的新型反应器，适合于所需单程反应时间较长且需颗粒间、气固间作用力较大——防黏结、提高传质效率等的气固反应体系.通过数学模型模拟研究了提升管预热方式、氧气初始浓度、初始炭矿比对用于四氯化钛生产的组合式流化床的反应特征和反应性质的影响，其中颗粒沿轴向的粒径分布变化通过粒子数平衡模型进行描述.模拟指出：富钛料主要的转化在湍床中进行；焦炭颗粒的燃烧反应存在“着火”温度(约873K）；氧气初始浓度和富钛料初始含量的增加能够增大富钛料的转化量，但氧气初始浓度达到一定程度（3.0mol•m^-3）后已不能有效增加富钛料转化量；氧气和氯气初始浓度高于某一数值时，在合适的氯化温度范围内（973～1373K），湍床才存在稳定的操作温度点.