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E x a m p l e s a n d Ca s e S t u d i e s 249

10.5.2 Water Pinch Technology: Second Problem
Problem 9: Task Assignment
Using the stream data from Problem 8, suggest a design of a network
for maximum reuse of water. The limiting CC is shown in
Figure 10.32.
Problem 9: Solution
Cut off the pockets of the limiting CC. The minimum water requirement for
each pocket can then be defined for each region (Figure 10.33). This enables one
to propose the design strategy shown in Figure 10.34.
Following the design strategy, set up a design grid as shown in Figure 10.35.
Connect streams to water mains and merge operations that cross boundaries;
see Figure 10.36.
Remove intermediate water mains where this is appropriate (Figure 10.37).
Then connect operations directly, as shown in Figure 10.38. Finally, Figure 10.39
illustrates (in conventional flowsheet form) one of the possible resulting designs
of the water system.

800

C [ppm] 400

100

0
1 9 21 41
m [kg/h]
FIGURE 10.32 Limiting Composite Curve for Problem 9.