Design with Transformed Triangles

Notice that in both configurations that they are very closely related to simple columns. For the side stripper, for instance, the simple column has a feed of flowrate F and quality q, a bottoms product of flowrate B and composition x. One can show by mass balance that CS2 produces a distillate product, or a pseudo distillate, of flowrate A2 = V2 — L2 and composition Xa2. Thus, for all practical purposes the CS above and below the feed is just a simple column with one feed and two products. One can in a similar way deduce that the CS2 in the side rectifier acts as a conventional product producing stripping section with a flowrate of — A2 =L2 — V2 (since product flowrates have to be positive) and bottoms composition of X.  

Recall that the X placement for both configuration display linear properties. Thus, it makes sense that X 2 can be viewed as a product since it displays the same mass balance properties as any normal product. Thus, the CPM parameters extend 

FIGURE 633 Column section breakdown across the feed stage for (a) a side strippo and (b) a ade rectifier. 

Since the CSs above and below the feed stream merely reduce to a pseudo simple column, it follows that we should be able to find the minimum reflux for it, just as we would do for a conventional simple column. The reflux in the CS below the feed (a stripping CS) can, exactly like simple columns (refer to Section 5.3.2), also be related to the reflux in a CS above the feed through  

If we only concern ourselves with sharp splits and constant relative volatilities, we can solve this problem by the TT approach. It is worthwhile noting that is also a sharp split product if we choose all products to be sharp (i.e., each product stream be completely depleted of at least one componoit) due to mass balance restrictions (see figure 6.29). Thus, following the same approach used for simple columns in 

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