Cross-Flow Liquid-Liquid Extraction

number of cross-flow stages

2

Consider the separation of

p

-dioxane and water using benzene as a liquid-liquid extraction solvent. The distribution coefficient is constant equal to 1.2 and the following relationship holds:

E

Y

=1.2

R

X

, where

E

Y

is the ratio of the masses of

p

-dioxane and benzene and

R

X

is the ratio of the masses of

p

-dioxane and water. 10000 kg/hr of a 25-weight-percent solution of dioxane in water is contacted with 15000 kg/hr of solvent in

N

S

cross-flow stages with solvent split. The Demonstration plots the equilibrium straight line in red and step-off stages using the user-specified value of

N

S

. Finally, the percent recovery of

p

-dioxane is displayed in green. It is clear that the percent recovery increases if one increases the number of cross-flow stages,

N

S

.