Maldistribution, packings, liquid effect

Liquid and vapor are well distributed. Both liquid and vapor maldistribution have a major detrimental effect on packing efficiency. 

Liquid redistributors are installed at frequent intervals in a packed column to remix the liquid, thus counteracting the propagation of maldistribution effects and the natural tendency of liquid to migrate toward the wall. A common design practice is to redistribute the liquid every 20 ft (6-7 m). 

Effect of changes In local L/V ratio on packing efficiency. Example 9.1 illustrates a 40 percent reduction in efficiency resulting from a liquid maldistribution of the order of as little as 5 percent between two halves of a column. A similar analysis of an actual troublesome maldistribution case history (140a) also showed that it does not take much maldistribution to cause a major efficiency loss. Example 9.1 also Illustrates the following ... 

Zuiderweg, Kunesh et al. (131,136,150,150a) combined the effects of local L[V ratio, lateral mixing, and liquid spreed into a single model that describes the effect of liquid maldistribution on packing efficiency. The work leading up to this model was performed at Fractionation Research Inc. (FRI) and at Delft University in The Netherlands. The model is still undergoing development. 

Figure 0.7 Comparing the effects of "small-scale and large-scale" maldistribution on packing HETP. (a) Comparing the effect of a simulated continuous tUt (max/ min flow ratio = 125 ) to the simulated effect of blanking a chordal area equal ts 11 percent of the tower area, (b) Comparing the effects of simulated continuous tilts (max/min flow ratios 125 and 1.5) to the effects of a situation where one-half of the distributor passes 25 percent more liquid to the other hen. (c) Comparing the effects of random maldistribution to these of zonal maldistribution. (Ae-...

---