Page 210 - Distillation theory

P1: FCH/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH
0521820928c06 CB644-Petlyuk-v1 June 11, 2004 20:17

184 Distillation Trajectories in Infinite Complex Columns and Complexes

D x '
D

F −
1
N 2 2
F 2 x rev m x E ( V ) max (E D )=∞
t
L
B a) K =1 K =1
3
3
+ S m
N
m
S m
K =1
α 13 3 132
L
(E D ) = 1 ( V ) = 1
min
min
1 3 1
13 13 3
x D
N − m
2 2
x E
b) K 3 =1 K 3 =1
x t rev ( V )
L
min
S
N + m
m (E D ) = 1
max
K =1
α 13 3 132
( V ) = 1
L
S m max
1 3 1 3
13 13 (E D ) (E D ) min
x D
D x '
3
Figure 6.8. Evolution of the region (bundle) of intermediate (extractive) section Reg R w,e
1,3,2 3 1,3,2 1,2
R
(shaded) located in component order region Reg ord (Reg w,e ∈ Reg ord ) with a variation
1,2
of E/D and L/V for the acetone(1)-water(2)-methanol(3) azeotropic mixture: (a) K 3 > 1
at point S m ; (b) K 3 < 1 at point S m . Short solid lines with arrows, tie lines liquid–vapor;
double arrows, a movement of point S m with a variation of E/D and L/V; component 1, top
product; component 2, entrainer.

2
R
Therefore, working trajectory region of the intermediate section Reg w,int con-
+
−
tains the separatrixes N − S m and S m − N . 1,3
m m
We now use general regularities of the location of the intermediate section
3
trajectories to analyze the evolution of trajectory bundle Reg R for azeotropic
w,e
1,2
mixtures on the example of a mixture acetone(1)-water(2)-methanol(3) (the sep-
arated mixture, 1,3 with azeotrope 13; entrainer, 2) (Fig. 6.8).
We note that this mixture cannot be separated into the components in a col-
umn with one feed. It is interesting for sharp extractive distillation to examine the