Page 156 - Distillation theory

P1: JPJ/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH
0521820928c05 CB644-Petlyuk-v1 June 11, 2004 20:15

130 Distillation Trajectories and Conditions of Mixture Separability

x D
2 2
a) b)
+
N (2)
x F
α α
x B 23 23
S
S
132
x x
D D
123
1 3 1 + 3
+ α α
− N (1) 23 − N (1) 23
N N
2 2
c) d)
+
N
α α
23 23

x x
D D
1 1 3
α S 3 α
− 23 − 23
N N
2,3
1
Figure 5.13. The evolution of trajectory bundles of the rectifying section (Reg R ≡ Reg )
att
w,r
1
(shaded) for an mixture with K 1 > K 2 > K 3 and α 23 line (component 1 is the product): (a)
1
1
L/V > K > K , (b) L/V > K 2 at point α 23 on side 1-2, (c) L/V > K 2 at point α 23 on side 1-3,
2 3
(d) arrow-ended lines show the progressive change of the separatrix position as L/V increases.
of the parameter L/V, the points S and N move away from point x t (Fig. 5.14b)
+
rev
until L/V = 1, when point S reaches vertex 2, and point N reaches vertex 3.
+
The section trajectory, the calculation direction taken into consideration, may be
presented in the following brief form (the calculation direction and characteristic
points given in the upper line [product components number in product points and
overall component number in other points in the upper index in parentheses], the
regions [including 0-dimensional] to which the points belong given in the lower
(2) (2) +(3)
line): x .
D → S r t → N r
Reg Reg Reg sh,R
D r sep,r
Let’s note that the top product point cannot be located at sides 2-3 and 1-3
because Eq. (5.15) is not valid for these sides (i.e., x D /∈ [2-3] and x D /∈ [1-3]).
Let’salsonotethattheseparatrixsharpsplitregionofsectiontrajectoriesbundle
3
S → N ≡ Reg sh,R at n = 3 and k = 2 is one-dimensional (i.e., at each value of
+
sep,r
1,2