Page 305 - Design and Operation of Heat Exchangers and their Networks

Optimal design of heat exchanger networks 291

Example H6C1—cont’d

Table 6.25 Problem data for H6C1 (Ciric and Floudas, 1991).
2
_
Stream T in (°F) T out (°F) C (kBtu/h°F) α (kBtu/ft °F) a Cost ($/kBtuyr)
H1 675 150 15 0.24
H2 590 450 11 0.118309859
H3 540 115 4.5 0.092307692
H4 430 345 60 0.118309859
H5 400 100 12 0.06
H6 300 230 125 0.080981595
C1 60 710 47 0.171428571
HU 800 800 51
CU 80 140 0.12 1.3582
2
Heat exchanger cost¼312.4A 0.6 $/yr (A in ft ), boiler cost¼135.9468Q 0.7
$/yr (Q in kBtu/h)
Total annual cost ($/yr)
Solutions in the literature Reported Revised
Ciric and Floudas (1991) 639,209 639,188
Papoulias and Grossmann (1983a) – 643,638
Floudas et al. (1986) a 647,050
Dolan et al. (1989) 644,480 644,817
a
Using SI units.
b
The original values are k H1C1 ¼0.1, k H2C1 ¼0.07, k H3C1 ¼0.06, k H4C1 ¼0.07, k H1C1 ¼0.055, and
2
k H1CU ¼0.08, k H5CU ¼0.04 (kBtu/ft °F).
3600
400 100
H5
(12)
3642. 124 1705. 908
675 150
(15)
1540 2527
590 450
H2
(11)
1912.5
540 115
H3
(4.5)
5100
430 345
H4
(60)
8750
300 230
H6
(125)
7899.5
710 60
(47) C1
(42.79313)
(26.21572) (10.82974)
Fig. 6.25 Optimal solution for Example H6C1, TAC¼639,188$/yr (Ciric and
Floudas, 1991).