Side draw columns

FKiURE 1.3 Examples of complex columns (a) distributed feed, (b) side draw columns, (c) thermally coupled side stripper, (d) reactive distillation column with reaction zone (R). 

FIGURE 3.2 CS breakdown for the (a) distributed feed column having five CSs and (b) side draw column with four CSs. 

SIDE-DRAW COLUMNS WITH LARGE SIDESTREAMS... 

It should be noted that many existing side-draw columns have neither composition controls nor ratio controls. In some cases the purge flows are so small that the loss of product in them is deemed negligible. In view of the rising cost of energy, however, many columns can make good use of steam/feed ratio controls. 

An Improved Approach to Composition Control of Side-Draw Columns 175... 

We will conclude this chapter with a brief discussion of some of the overrides that may be encountered on side-draw columns. We will choose, as an example, the column of Figure 9.19. This is a purification column in a solvent-recovery system. A small amount of low boilers must be removed overhead, and a small amount of high boilers must be removed as bottom produrt. Most of the feed is taken off as sidestream. Following are the most important overrides. ... 

Side-Draw Columns with Large Sidestreams 169... 

Side-Draw Columns with Small Sidestreams 170... 

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