1. Regenerative Rankine Cycle
P M V Subbarao
Professor
Mechanical Engineering Department
Carnotization of Practicable Cycles for PGS…..

2. Carnotization of Rankine Cyce
Supercritical Steam Generation
Liquid
Liquid +Vapour
Vapour
h mfuel s

3. Reassessment Thru Carnot Model

4. Diagnosis of Heat Addition Rankine Cycle

5. Diminishing Local Work Conversion

6. Diminishing Marginal Work Generation
wturbine

7. Diminishing Local Efficiency

8. What about a Non-Isentropic Expansion !!!4
A Macro Carnot Cycle !!!! 3 5 T 2 6 1 7 s

9. Ideal Regenerative Cycle4 5 6 7 3 2 1

10. Regenerative Turbine 4 7 T
Regenerative heat transfer. Change in kinetic and potential energies are negligible
Assuming a single fluid entering and leaving…

11. Analysis of Regeneration Cycle1 2 4 5 6 7 3

12. Regeneration Cycle with Bleeding Turbine & Mixer (Open Feed Water Heater)

13. Analysis of mixing in OFWH
Constant pressure mixing process
Constraint:
Maximum allowable value of h3 is p3
Conservation of energy:

14. Analysis of Regeneration through OFWH

15. Cost to Benefit Ratio for Regenerative Rankine Cycle

16. Performance of OFWH Cycle
~ 12MPa
hreg
pbleed, MPa

17. Clues for Optimal Location of FWH

18. Comparison of Performance of Bleed & Condensing Steams
hcond
hbleed
Pregen, MPa

19. Gross Work output of bleed Steam
~ 12MPa
wbleed
pregen, MPa

20. Workoutput of bleed Steam
Fractional specific output
Fraction of Bleed Steam

21. Workoutput of bleed Steam
wbleed

22. Progress in Rankine Cycle
Year
1907
1919
1938
1950
1958
1959
1966
1973
1975 MW 5 20 30 60
120
200
500
660
1300
p,MPa
1.3
1.4
4.1
6.2
10.3
16.2
15.9
24.1
Th oC
260
316
454
482
538
566
565
Tr oC --
FHW 2 3 4 6 7 8
Pc,kPa
13.5
5.1
4.5
3.4
3.7
4.4
5.4
h,%
~17
27.6
30.5
35.6
37.5
39.8
39.5 40

23. Thermodynamic Analysis of A Power Plant

25. Block Diagram of A Large Steam Turbine
Main Steam
Reheat Steam HP IP LP
Steam for
Reheating
OFWH 4
CFWH 3
CFWH 2
CFWH 6
CFWH 5
CFWH 1
Condenser