Page 320 - Distillation theory

P1: JPJ/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH
0521820928c08 CB644-Petlyuk-v1 June 11, 2004 20:20

294 Synthesis of Separation Flowsheets

2 2
a) b)
42135 42135
42153 42153 42135
42153
42513 42513
24
45213 45213 42153
24153
1 4 1 15 5
24153
24135
24135
35
3 3
2 3
c) d)
42135
42135
35
42153 24135
24153
42513 42513
42153
45213 45213
24 15 15 42153
1 5 1 5

24153

4 4
i, j,k j j
(4) t(4) t(4)
Figure 8.14. Component-order Reg on four-
ord and tear-off regions Reg r and Reg s
i i
component hyperfaces of the water(1)-methanol(2)-acetic acid(3)-acetone(4)-pyridine(5) con-
centration pentahedron (hatched for the overhead product and shaded for the bottom product):
5 4 3 2
t(4)
t(4)
t(4)
t(4)
(a) Reg r , (b) Reg s , (c) Reg r , (d) Reg s .
1,2,3,4 1,2,3,5 1,2,4,5 1,3,4,5
t(3)
corresponding to these segments trajectory tear-off regions Reg e in two-
t(4)
dimensional faces and Reg e three-dimensional hyperfaces, respectively. Fig-
ure 8.15 shows the direction of residue curves at edges of the pentahedron. It
is seen in Fig. 8.15 that all vertexes of the pentahedron are saddles (i.e., cannot
be product points in a simple column). As one can see in Fig. 8.12, segments
t(2)
Reg r,s of trajectory tear-off from the edges of the pentahedron inside it are
1,3,5
t
available only at edge 2-4 − Reg (in any point of this edge, the absent com-
r
2,4 2,4,5
t
ponents [1,3,5] are the heaviest ones), at edge 1-3 − Reg (at segment [1, α 15 ] the
s
1,3
components absent at the edge [2,4,5] are the lightest ones), and at edge 3-5 −
1,2,4
t
Reg (in any point of this edge, the absent components [1,2,4] are the lightest ones).
s
3,5