Recent Developments in Reheat Rankine Cycle

BY

P M V SubbaraoProfessor

Mechanical Engineering DepartmentI 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

Pc,kPa 13.5 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

Reheating : A Means to implement High Live Steam Pressure

Impr

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y, % 593/6210C

593/5930C565/5930C

565/5650C

538/5650C

538/5380C

Supercritical

Modular Construction of Steam Turbine

Super Critical Cycle ~ 1990

Single-Reheat Ultrasupercritical Product LineGE 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

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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 LineGE Power