1. Pinch technology series
Heat Integration
An Introduction to
Heat Exchanger Network (HEN) Design
By:
Anwaruddin Hisyam
Pinch technology series

2. Pinch technology series
In this lecture we will learn how to set energy recovery targets for a process.
Pinch technology series

3. Pinch technology series
Pinch identification
Pinch technology series

4. Pinch technology series
Base case
Reactor
50 C
160 C
270 C
210 C
220 C
180 C
60 C
130 C
149 C
1620
2640
1980
1220
178 C
880
Pinch technology series

5. Pinch technology series
Data Extraction
178 C
880
1620
160 C
180 C
60 C
2640
130 C
210 C
Reactor
270 C
160 C
210 C
149 C
1220
1980
50 C
220 C
Pinch technology series

6. Pinch technology series
…..from data extraction
Reactor
50 C
160 C
270 C
210 C
220 C
60 C
130 C
Pinch technology series

7. Stream Data (Problem Table)No
T source, C
T target, C
Heat duty, kW CP
Type 1
220 60
3520 22
Hot 2
270
160
1980 18 3 50
210
3200 20
Cold 4
2500
CP = Heat duty/ABS(T source – T target)
Pinch technology series

8. Pinch technology series
Composite Curve
DT min
Pinch technology series

9. Pinch technology series
Set DTmin = 20 C
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10. Pinch technology series
Shifted Stream Data Hot - ½DTmin; Cold + ½DTmin No
T source, C
T target, C
Heat duty, kW CP
Type 1
210 50
3520 22
Hot 2
260
150
1980 18 3 60
220
3200 20
Cold 4
170
2500
Pinch technology series

11. Shifted Composite Curve50
100
150
200
250
300
1000
2000
3000
4000
5000
6000
7000
Heat Duty (kW)
Temp interval (K)
Pinch technology series

12. Pinch technology series
Cascade Diagram
Cold-Hot
Stream population
Cold
Hot
260
220
210
170
150 60 50
720
-720
SURPLUS
700
180
520
DEFICIT
2800
1600
1200
400
800
-400
1800
1980
-180
220
-220 18 20 50 22
Pinch technology series

13. Heat balance in the interval
Hot utility
Heat flow
260
220
210
170
150 60 50
720
200
- 1000
- 600
- 420
- 200
-720
520
1200
-400
-180
-220
Cold utility
Pinch technology series

14. The heat flow must NOT be negative
Pinch technology series

15. Pinch technology series
Normalization
260
220
210
170
150 60 50
720
200
- 1000
- 600
- 420
- 200
Hot utility
-720
520
1200
-400
-180
-220
Cold utility
Need additional heat
Pinch technology series

16. Original Grand Composite Curve
Unfeasible region
Feasible region
Pinch technology series

17. Pinch technology series
…finding pinch
260
220
210
170
150 60 50
1000
1720
1200
400
580
800
Hot utility
-720
520
-400
-180
-220
Cold utility
No heat flow at this point
Eureka....!
This is the PINCH
Pinch technology series

18. Pinch technology series
Grand Composite Curve
Qh min
Qc min
Pinch technology series

19. Pinch technology series
finally…. The PINCH POINT = 170 C which means that Hot stream PINCH = 170+½DTmin = Cold stream PINCH = 170-½DTmin = 160
Pinch technology series

20. Pinch technology series
Heat source and sink
Heat source  this part releases heat
Heat sink  this part requires heat
PINCH
Heat Source
Heat Sink
Pinch technology series

21. and, how can we design HEN based on the pinch?
Pinch technology series

22. Base case….the existing network
220 60
270
160
210 50 H C
2640
1620
880
1980
1220
Heat recovery = = 2860 kW
Cold utility = 2640 kW
Hot utility = = 2840 kW
Pinch technology series

23. Let’s start from the pinch
Pinch technology series

24. Pinch technology series
220 60
270
160
210 50
180
2200
AT 170
PINCH
360
2640
1000
2500
1640
880 20 18 22 CP
BELOW
ABOVE
Pinch technology series

25. Pinch technology series
Rules….
CP in ≤ CP out
Start finding partners for streams OUT (with streams IN, away from pinch, or utility)
N stream IN ≤ N stream out
If Ns IN > Ns OUT, split stream(s) OUT
If CP in > CP out (no match), try to split stream(s) IN
Set maximum heat recovery
The remaining heat duty is covered by heater or cooler
Pinch technology series

26. Pinch technology series
Step 1: Below the PINCH
Connect S1(22) and S3(20)
CP in < CP out
220 60
270
160
210 50 1
180
2200 √
Pinch technology series

27. Pinch technology series
Step 2: Above the PINCH
Connect S2(18) and S4(50)
CP in < CP out
220 60
270
160
210 50 1
180
2200 √ 2
1620
Pinch technology series

28. Pinch technology series
Step 3: Above the PINCH
Connect S1(22) and S4(50)
CP in < CP out
220 60
270
160
210 50 1
180
2200 √ 2
1620 3
880
2500
Pinch technology series

29. Pinch technology series
Step 4: Above the PINCH
Install Heater at S3(20)
220 60
270
160
210 50 1
180
2200 √ 2
1620 3
880
2500 H
1000
Pinch technology series

30. √ √ √ √ √ √ √ All heat requirements have been met !!!
Step 5: Below the PINCH
Install Cooler at S1(22) and S2(18)
440
880 √
180 √
2640 60 C 1 3
220
880
360
1620 √
180 √
360 C
160 2
270
1620
1000 √
160 √ H
2200 50 1
210
1000
2200
160 √ 3 2
160
210
2500
All heat requirements have been met !!!
Pinch technology series

31. …finally… Heat Exchanger Network (HEN)
220 60
270
160
210 50 H
2200
440
1000
1620
880 C
360
Maximum Energy Recovery (MER) = = 4700 kW
Minimum cooling heat duty (Qc min) = = 800 kW
Minimum heating heat duty (Qh min) = 1000 kW
Pinch technology series

32. Then draw the flowsheet…
Reactor
50 C
160 C
270 C
210 C
220 C
60 C
130 C
880
1620
2200
440
360
1000
177.6 C
180 C
80 C
Pinch technology series

33. Possible modifications
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34. Pinch technology series
Grand Composite Curve
MP steam
Heat generation
Cooling water
Pinch technology series

35. Pinch technology series
Thank you
Pinch technology series

36. Pinch technology series
Working Session
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37. Pinch technology series
How will the HEN be….?
Feed 2
Feed 1
H= 27 MW
H=32 MW
H= MW
H=-30 MW
140 C
250 C
230 C
40 C
180 C
20 C
200 C
80 C
Product 2
Product 1
Reactor 1
Reactor 2
Pinch technology series