精馏塔板相界面积的粒数衡算模型

POPULATION BALANCE MODEL FOR PREDICTING INTERFACIAL AREA ON DISTILLATION TRAY

通过对气液湍流系统中气泡的动力学行为进行分析推导出气泡破碎速率与聚并速率的表达式 ,在此基础上建立了描述气泡分散特性的粒数衡算模型 .求解粒数衡算方程可以计算精馏塔板上气泡的粒度分布以及气液相界面积 ,模拟计算的结果与实验测量的数据相当一致 ,证明可以利用粒数衡算模型较准确地预测气液湍流系统的分散性质 .

The bubble dispersion behavior in the liquid on a sieve tray is studied on the basis of Kolmogoroff's isotropic turbulence theory. The bubble breakage rate model is derived from the mechanism of deformation of bubbles bombarded by the turbulent eddies and the probability of bubble breakup, and the bubble coalescence rate model is developed through comparison between the contact time of bubbles and the time required for bubble coalescence. The dynamic bubble population balance model is established on the basis of comprehensive analysis of the effect of breakage and coalescence on bubble size distribution in the bubbling liquid, and is solved numerically to give bubble population density which is analogous to the lognormal distribution function and is in agreement with the experimental results. The population balance model has been proved to be useful for predicting the gas-liquid interfacial area, which is important to the design of distillation tray and optimization of distillation operation. So it has good prospects for the accurate simulation of the dispersion characteristic of the multiphase turbulent system in processing engineering.