1. Heat Integration Chapt. 10

2. Costs Heat Exchanger Purchase Cost – C P =K(Area) 0.6 Annual Cost –C A =i m [ΣC p,i + ΣC P,A,j ]+sF s +(cw)F cw i m =return on investment F s = Annual Flow of Steam, –$5.5/ston to $12.1/ston F cw =Annual Flow of Cold Water –$0.013/ston

3. Lost Work = Lost Money Transfer Heat from T 1 to T 2 ΔT approach Temp. for Heat Exchanger T o = Temperature of Environment Use 1 st and 2 nd laws of Thermodynamics LW=QT o ΔT/(T 1 T 2 ) T1T1 T2T2 Q

4. Minimize Utilities For 4 Streams

5. Simple HEN

6. Adjust Hot Stream Temperatures to Give ΔT min

7. Enthalpy Differences for Temperature Intervals

8. Interval Heat Loads

9. Pinch Analysis Minimum Utilities

10. Pinch Analysis

12. 4 Heat Exchanger HEN for Min. Utilities

13. Minimum Utilities HEN

14. Too Many Heat Exchangers Sometimes fewer Heat exchangers and increased utilities leads to a lower annual cost N Hx,min = N s + N U - N NW –No. streams –No. discrete Utilities –No. independent Networks (1 above the pinch, 1 below the pinch Solution to Too Many Heat Exchangers –Break Heat Exchanger Loops –Stream Splitting Attack small Heat Exchangers First

15. Break Heat Exchanger Loops

16. Example

17. Change ΔT min C P =K(Area) 0.6 Area=Q/(UF ΔT min )

18. Distillation Columns

19. Position a Distillation Column Between Composite Heating and Cooling Curves

20. Heat Integration

21. Multi-effect Distillation Adjust Pressure in C2 for ΔT min

22. Heat Pumps in Distillation