The effect of the separation factor (alpha) on a separation process as seen in the

McCabe-Thiele diagram

As we can see from the figures below ¹, the separation factor affects the number of stages necessary to obtain a desired separation. This can be seen in the different McCabe-Thiele diagrams, which constitute of the operating line (solid line) and an equilibrium line (dotted line).

For this example, we wanted a product stream of 0.9 and a waste stream of 0.1.

Figure 1: McCabe-Thiele diagram for alpha = 3.75

N = 4.3

Figure 2: McCabe-Thiele diagram for alpha = 2.5

N = 5.8

Figure 3: McCabe-Thiele diagram for alpha = 1.25

N = 20.7

Figure 4: McCabe-Thiele diagram for alpha = 1.0

N = infinity (can not be separated this way)

1. These graphs were obtained using ex2353.mw.