滴流床的压降和持液量

Pressure Drop and Liquid Holdup in Trickle Bed

以α-甲基苯乙烯加氢系统为对象,研究滴流床的流体力学特征,在冷态条件下测定了滴流床内压降和持液量,得到压降、动持液量与气速和液速的关系式。结果表明压降梯度受气速影响较液速大,动持液量受液速影响较气速大。气速增加,床层压降增大,动持液量减小;静持液量只与体系的物性、填料物性、装填方式等有关,与反应条件无关。另外,在零气速条件下,用KOH作为示踪剂,采用脉冲注入法,研究了滴流床的停留时间分布,得到床层的Peclet准数与液速的关系,Peclet准数随着液速的增加按指数级增加。

The hydrodynamics characteristics of trickle bed reactor was studied using α-methylstyrene hydrogenation system as mediums. The pressure drop and liquid holdup were observed and determined in cool condition. Subsequently, the equations of pressure drop and liquid holdup with the gas and liquid velocity were obtained. Gas velocity plays more important role than liquid velocity for pressure drop, but the dynamic liquid holdup is influenced by liquid velocity more remarkably. The pressure drop increases and dynamic liquid holdup decreases with increasing gas velocity. Static liquid holdup is only related to the physical properties such as system and packing, packing methods, and has nothing to do with the operating conditions. In addition, the residence time distribution of trickle bed was studied using water as liquid phase, KOH as tracer with a method of impulse input under no gas added condition. The relation of Peclet number and liquid velocity is obtained. Peclet number shows an exponential growth with the liquid velocity rising.