Page 324 - Distillation theory

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

298 Synthesis of Separation Flowsheets

a) t 1 b) 1 c) x t 2− 3− 4 2
x 1− 2− 4 x B t
x 1− t 2− 5 x 1− 3− 4
24
15 15
4 5 4 5 4 x B 5
24 x B
x 1− t 3− 5

2 3 3
d) 2

1 3
4,5
(3)
Figure 8.18. Determination of possible bottom product region Reg B on three-component
1,2,3
face 1-2-3 of the water(1)-methanol(2)-acetic acid(3)-acetone(4)-pyridine(5) concentration
pentahedron. Segments of possible bottom product on the binary edges of face 1-2-3: (a)
4,5 4,5 4,5
(2) (2) (2)
Reg B (double thick segment), (b) Reg B = [1-3](whole double thick edge), (c) Reg B = 0
1,2 1,3 4,5 2,3
(absent), and (d) region of possible bottom product on the face 1-2-3 Reg (3) (shaded).
B
1,2,3
(2)
the segments of possible top product Reg bound,D at all the edges of this hyperface:
3 3
Reg D at edge 1-2 at distillation of mixture 1,2,3, Reg D at edge 1-4 at distillation of
1,2 1,4
3 3
mixture 1,3,4, Reg D at edge 1-5 at distillation of mixture 1,3,5, Reg D at edge 2-4
1,5 3 2,4
at distillation of mixture 2,3,4, Reg D at edge 2-5 at distillation of mixture 2,3,5,
2,5
3
and Reg at edge 4-5 at distillation of mixture 3,4,5. One can see in Fig. 8.16 that
D
4,5
any point of all these edges is a possible top product point. Therefore, we can
consider that the whole hyperface 1-2-4-5 is filled up with possible top product
3 (4)
points ({1-2-4-5} ≡ Reg D ∈ Reg ).
D
1,2,4,5
It follows from the analysis made that in a column with one feeding only two
splits without distributed components are feasible: (1) 2,4 : 1,3,5 and (2) 1,2,4 :
3,5.
Split 1,2,4,5 : 1,3 is the most interesting among splits with one distributed com-
ponent that is feasible at any feed composition because hyperface 1-2-4-5 and
(4)
edge 1-3 are entirely filled up with possible product points ({1-2-4-5}∈ Reg and
D
(2)
[1-3] ∈ Reg ).
B