Page 306 - Design and Operation of Heat Exchangers and their Networks

292 Design and operation of heat exchangers and their networks

Example H4C4
This example was taken from He and Cui (2013), as is shown in Table 6.26,
which was originally used by Grossmann and Sargent (1978). Luo et al.
(2004) used this example for the optimal design of multistream heat
exchanger networks. In their calculations, they took the overall heat
2
transfer coefficient of 0.15kBtu/ft °F for all units. We find that their
final network will also become the best design of the two-stream heat
exchanger network even we use the problem data given in Table 6.26,
which yields TAC¼29,216$/yr after the revision. The corresponding
network is shown in Fig. 6.26, in which there are two independent
variables for stream splitting.

Table 6.26 Problem data for H4C4 (He and Cui, 2013).
2
_
Stream T in (°F) T out (°F) C (kBtu/h°F) α (kBtu/ft °F) Cost ($/kBtuyr)
H1 470 320 22.4 0.3
H2 450 240 17.5 0.3
H3 370 150 28.5 0.3
H4 310 200 20.1 0.3
C1 200 420 16.8 0.3
C2 150 400 23.2 0.3
C3 185 330 35.1 0.3
C4 140 300 17.25 0.3
HU 456 456 0.6 11.05
CU 100 180 0.3 5.31
0.6 2
Heat exchanger cost¼35A $/yr (A in ft )
Total annual cost ($/yr)
Solutions in the literature Reported Revised
Luo et al. (2004) for multistream HE – 29,216
Zhang et al. (2017) a 30,783 30,777
He and Cui (2013) a 30,793 30,794
Souto et al. (1992, Fig. 8) a,b – c 30,869
a
No stream split.
b
Using SI units.
c
After revision, H3CU and HUC3 are deleted.