Page 250 - Distillation theory

P1: JPJ/FFX P2: JMT/FFX QC: FCH/FFX T1: FCH
0521820928c07 CB644-Petlyuk-v1 June 11, 2004 20:18

224 Trajectories of the Finite Columns and Their Design Calculation

2
+
(x F − S − N ) lin . The equation of this straight line can be found by means of solv-
s s
ing the system of equations describing the mentioned manifolds by coordinates
of the stationary points entering into them and of point x F . Then the coordinates
∞ sh
of points (x min sh and (x ) at this straight line are determined from Eq. (5.18).
)
f −1 lin f lin
)
The coordinates of points (x min sh and (x ∞ ) sh are determined in the same way
f lin f −1 lin
(Fig. 7.1c).
Possible composition segments at the first trays above and below the feed cross-
section in the real columns [x f −1 ] and [x f ] located at vicinity of curvilinear sepa-
2
2
1
1
+
ratrix manifolds Reg sh,R (S − S − N ) and Reg sh,R (S − S − N ), or inside the
+
sep,r r r r sep,s s s s
working trajectory bundles Reg R and Reg R , correspond to segments [x f −1 ] sh
w,r w,s lin
and [x f ] sh .
lin
1
2
+
At the direct split, S ≡ N and S ≡ N (Fig. 7.2a). Therefore, at the direct
−
r r s s
split, segment [x f −1 ] is located inside working trajectory bundle of the top section
x 2
D
x F a)
x
B
x ∞
min f−1
x
f−1
x D
min
x
1 f 4
∞
x ≡ N +
f s
3
2
b)
x min
f−1
∞ ∞ +
x x ≡ N
f f−1 r
x min
f
1 4
x
B
3
2,3,4
Figure 7.2. Section regions at given reflux Reg R w,r =
1 1,2,3 4 1
4
1
Reg , Reg sh,R and Reg R = Reg , Reg sh,R and
att sep,s w,s att sep,r
2,3,4 4 1,2,3
possible composition segments [x f −1 ] and [x f ] in feed
cross-section: (a) direct split, (b) indirect split. Separa-
trix sharp split section regions are shaded.