Page 301 - Distillation theory

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

8.2 Zeotropic Mixtures 275

pseudocomponents: C 3 H 8 ,(i-C 4 H 10 + 1-C 4 H 8 ), n-C 4 H 10 , i-C 8 H 18 ,C 9 H 20 (here
[i-C 4 H 10 + 1-C 4 H 8 ] − one pseudocomponent) with molar composition (0.05; 0.70;
0.10; 0.10; 0.05). In this case, as earlier, the flowsheet of direct separation is the
best one in total expenditures and in summary vapor flow rate V.
Besides sequences of simple columns, some types of distillation complexes, each
of which can replace two adjacent simple columns, were examined in work (Glinos
& Malone, 1988). The following complex columns and distillation complexes were
examined: column with side output above the feed cross-section, column with
side rectifier, column with side stripping; flowsheet with prefractionator, Petlyuk
column; top and side flows from the first column into the second one (Fig. 8.3a),

1

a) 1,2 b)
1

2
1,2 1,2,3

2,3
1,2,3
2

2,3
3

3
c) d)
1 1 1

2
1,2
1,2,3

2,3
1,2,3
2

3 3 3
Figure 8.3. Some complex columns for the ternary mixtures: (a) indirect
with overhead product and sidestream of first column between columns,
(b) direct with bottom product and sidestream of first column between
columns, (c) indirect with sidestream of first column between columns,
and (d) direct with sidestream of first column between columns.