Rectifying section operating line

One point is on the 45° line at Xr, and the slope is Ls/Vs, where S refers to the stripping section. Another point is the intersection of the rectifying section operating line with the q line. And still another point is on the Y axis at the location below the origin of -(B/Vs)(Xb). 

Equations for Stepwise Tray to Tray Calculations Rectifying Section Operating Line... 

Referring to Figure 9-98 for the graphical solution Rectifying section operating line slope = ... 

It is also known that D=V, and when this expression for D is substituted in the above equation, the result is Y=X= Kj. That is, the rectifying section operating line intersects the diagonal at the distillate composition. Similarly, it may be shown that the stripping section operating line intersects the diagonal at Y = X = Xf the bottoms composition. 

If the reflux ratio, or L,/D, and the distillate rate, D, are specified, the rectifying section operating line slope, L,/y, can be calculated. The feed composition and thermal conditions are also known, which allows the -line to be plotted and and V, to be calculated from Equations 5.16 and 5.17. Thus, the slopes of the two operating lines are known as well as the locus of their intersection points. 

If the reflux ratio is increased, the slope of the rectifying section operating line increases, the operating lines move farther away from the equilibrium curve, and... 

With a reflux ratio R = 4, the solvent-free L/V) slope of the rectifying section operating line is... 

The rectifying section operating line is drawn based on this slope and the dis-... 

The calculations could be carried one step further, utilizing the relationship between the rectifying section operating lines as develope< in Chapte 4 that is, L/D (or L/V) and establish a relationship between V/B (or L/V or V/L) and Xg. This refinement, however, introduces an extra element of trial and error. 

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