Recent Developments in Reheat Rankine Cycle
BY
P M V Subbarao
Professor
Mechanical Engineering Department
I I T Delhi
New Efforts to Realize Isothermal Heat Addition…..
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
15.9
24.1
Th oC
260
316
454
482
538
566
566
565
538
Tr oC
--
--
--
--
538
538
566
565
538
FHW
--
2
3
4
6
6
7
8
8
5.1
4.5
3.4
3.7
3.7
4.4
5.4
5.1
~17
27.6
30.5
35.6
37.5
39.8
39.5
40
Pc,kPa 13.5
h,%
--
Reheating : A Means to implement High Live Steam
Pressure
Improvement in Efficiency, %
Supercritical
593/6210C
593/5930C
565/5930C
565/5650C
538/5650C
538/5380C
Modular Construction of Steam Turbine
Super Critical Cycle ~ 1990
Single-Reheat Ultrasupercritical Product Line
GE Power
Modular High-Temperature Gas-Cooled Reactor
Modular High-Temperature Gas-Cooled Reactor
with Supercritical Rankine Cycle
Model – 2 :MHTGR
Special Features
• SG for the Life Steam Supplier : For the selected turbine set, the
feedwater temperature is 283°C, while the SC steam parameters
at SG outlet are 25.4 MPa/571°C.
• For the helium side of SG, the inlet temperature is kept at
750°C to maintain 179°C temperature difference between the
helium and the SC steam for effective heat transfer.
• The outlet helium temperature should be increased from 250°C
for the standard MHTGR-250 design to 330°C to maintain
effective heat transfer between the helium and the feedwater.
• Although high steam pressure and temperature involves
modifications of the once-through SG and relevant pipes, no
additional difficulties in design and manufacture are expected.
• (Reheat Exchanger for Reheat Steam Supply
• For the selected turbine set, the steam parameters at the
inlet of the reheat exchanger are 4.38 MPa/311°C and
4.19 MPa/569°C at the outlet.
• For the helium side of reheat exchanger, the helium
temperature at both inlet and outlet should be 350°C/750°C.
Deployment mode of MHTGR SC plant with life
steam reheat cycle
Double Reheat Ultra Super Critical Cycle
8
Improvement in Efficiency, %
Super Critical Cycle of Year 2005
Double Reheat Super Critical Plants
Net efficiency on natural gas is expected to reach 49%.
Net efficiency on coal is expected to reach 47%.
Super Critical Cycle of year 2010
> 50 %
Double-Reheat Ultrasupercritical Product Line
GE Power