Be Frank on Reconciliation or Breakup …… Future Policy on Embedment of Reheat and Regeneration in Rankine Cycles P M V Subbarao Professor Mechanical Engineering Department Be Frank on Reconciliation or Breakup ……

Macro Differences in Cycle due to Reheat Vs Regeneration

Regeneration in Reheat Cycle

Regeneration in Reheat Cycle

Regeneration in Reheat Cycle

Regeneration in Reheat Cycle

The Breakup !!!!

Power Plant with an Auxiliary Turbine A substantial rise in the temperature of steam, especially reheated steam (to 720C), aggravates the problem of the difference between the bleed steam and the heated water temperatures in FWH. This is more serious issue with heaters fed with bleeds from the intermediate pressure turbine, which are situated right after the steam reheater. Passing the bleeds from the intermediate pressure part of the main turbine to a separate extraction backpressure turbine fed from the turbine high pressure turbine outlet before the first reheat will decrease overall irreversibility By keeping pressures in the bleeds at the same level, the temperature differences in the heaters fed from the auxiliary turbine are much lower.

900 MW Advanced ultra-supercritical power unit with single reheat 7.5MPa &720C 35MPa &700C 330C 0.005 MPa

900 MW Advanced ultra-supercritical power unit with single reheat with AT

Impact of AT on Single Reheat AUSC

900 MW Advanced ultra-supercritical power unit with Double reheat 13MPa &720C 3MPa &720C 37.5MPa &700C 332C 0.005 MPa

900 MW Advanced ultra-supercritical power unit with Double reheat & AT -1

900 MW Advanced ultra-supercritical power unit with Double reheat & AT-2

Impact of AT on Double Reheat AUSC

Basic indices of the 900 MW power unit in various configurations

Efficiency of Danish Coal-Fired Power Plants Continuous development resulted around the mid 80's in an average efficiency of 38% for all power stations, and best values of 43%. In the second half of the 1990’s, a Danish power plant set a world record at 47%.

Average efficiency, specific coal usage, CO2 emissions h Indian Coal Plants: Efficiency of modern coal power plant = 34-36% Efficiency of old power plant = 20-30%

Emission-Free Sources of Electricity Another compelling reason to consider building new nuclear plants is that nuclear energy helps keep our air clean. For example … in 2004, nuclear power plants prevented the emission of almost 700 million metric tons of carbon dioxide, the principal greenhouse gas. That is nearly three times the amount of carbon dioxide prevented by other forms of emission-free sources of electricity. Nuclear energy accounts for nearly three-quarters of all emission-free electric generating capacity in the United States and is best positioned for future large- scale growth. Recent studies by the Earth Institute at Columbia University and Princeton have identified the benefits of nuclear energy for our future air quality and to mitigate climate change.

Life Cycle of Nuclear Fuel Safe Disposal

Comparison of Life-Cycle Emissions Tons of Carbon Dioxide Equivalent per Gigawatt-Hour

Types of Reactors Pressurised water reactors (PWR, VVER) Boiling water reactors (BWR) Pressurised heavy water reactor (PHWR) Gas-cooled reactors (Magnox, AGR, UNGG)

Power reactors under construction

Power reactors under construction

Power reactors under construction