Page 126 - Sustainability in the Process Industry Integration and Optimization

P r o c e s s I n t e g r a t i o n f o r I m p r ov i n g E n e r g y E f f i c i e n c y 103

Natural Gas

Coal Fuel Oil
Current: 250.0 Current: 55.4
[50.0; 250.0] [40.0; 180.0] GT
HRSG 18 MW
Boiler 1 Boiler 2 Air
Current: 208.4 Current: 28
[115.0; 335.0]
Current: 105.0
VHP (101 bar abs.)
[60.0; 165.0]
Current: 15.0 T4 Current: 59.5 T6 20.0
[15.0; 75.0] [15.0; 65.0] 0.0
HP (41 bar abs.)
Current: 90.0 Current: 40.9
T5 54.5
[30.0; 9.0] [30.0; 70.0] 0.0
MP (15 bar abs.)
0.0
Current: 20.0 Current: 108.0 55.9
[20.0; 20.0] T7 [60.0; 150.0] 0.0
LP (3 bar abs.)
LP Vent
CW
0.073 bar abs. Current: 75.0 128.0
[40.0; 75.0]
All flowrates are in [t/h]. The lower and upper bounds are shown in the format [min;max].
FIGURE 4.69 Optimized utility system.

FIGURE 4.70 Marginal
steam prices for the 8 HP Steam MP Steam
utility system shown in 7
Figure 4.69. 6
Marginal Price, $/t 5

4
3
2
1
0
0 10 20 30 40 50 60 70
Steam Savings, t/h

Figure 4.69 is shown in Figure 4.70. The plot indicates that the most
potential for improvements is in the HP steam using processes,
followed by MP users; the potential for LP steam savings is evidently
quite modest.