气体搅动的筛板萃取塔性能实验研究

Experimental study on performance of sieve plate extraction column with air-agitation

在筛板萃取塔中引入气体搅动,既能明显提高装置的传质效率,又能大幅提高装置处理能力。筛板塔的通量随气速的变化规律与填料塔有显著区别,其性能研究有重要意义。利用煤油(苯甲酸)-水-空气体系,考察了气体搅动和筛孔直径对萃取塔流体力学和传质性能的影响。结果表明,随着表观气速的增加,气含率、分散相含率、液泛速率和传质效率均明显增加。但过高的气速也会导致分散相的过于分散和乳化,传质性能下降,直至液泛。不同直径的筛孔相比,较小的筛孔使分散相停留时间延长,分散相含率和传质效率提高,但液泛速率和处理能力降低。

Both mass transfer efficiency and throughput capacity of sieve plate extraction columns can be greatly improved with air-agitation. Especially the effect of air-agitation on throughput capacity of sieve column is completely different from that of packing column, and the study on performance of sieve column with air-agitation is very important. The effects of air-agitation and holes diameter of sieve plates on hydrodynamics and mass transfer were investigated through experiments with air-kerosene （benzoic acid）-water system. It shows that air holdup, dispersed liquid phase holdup, flooding velocity and mass transfer coefficient increase significantly with the increasing of superficial air velocity. But over-velocity of air would result in over dispersion and emulsification of dispersed liquid phase, reduction of mass transfer performance and even flooding. Smaller holes would result in longer residual time and larger holdup for dispersed liquid phase, thus the mass transfer efficiency is higher but flooding velocity or throughput capacity is smaller for smaller holes.