Distillation - Principles of Chemical Separations with Environmental Applications - page 108

1

0.9

0.8

0.7

0.6

y A

0.5

0.4

0.3

0.2

0.1

0

0.9

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 1

x B = 0.12 x A x D

Figure 4.15 Stepping off stages for partial condenser, Example 4.4.

y

x 2 y 1

y 1

Steam
injection

x 1 y B

y B

Steam
S

~

x 1

x B

B , x B

x

Bx

x= Bx B x =

B

B-S ~

~

B

− S

Figure 4.16 Steam injection.

Steam injection

Steam distillation, as shown in Figure 4.16, uses steam injection instead of a reboiler
to provide heat. One advantage is a lower operating temperature. This approach is often
preferable for wastewater treatment (steam stripping) when the contaminant concentration
in the exit water stream must be very low. The operating line for the stripping section is
still valid:

L
V x m + 1 −

Bx B
V .

y m =