Combine Cycle Power Plant

1. Combine Cycle Power Plant Presented By Ashvin G. Patel Asst. Prof. (E.E.) GPERI, Mehsana

2. Combine Cycle Power Plant: • In combined cycle power plant (CCPP), the Brayton cycle & Rankinecycles are combined.

3. Cont… • The exhaust of gas turbine which is at a high temperature is supplied to steam generator as a input. • The heat energy of exhaust gas is absorbed by water. This water converts in to high pressure steam which is supplied to the steam turbine and additional electricity is generated. • Steam is taken from the turbine condense in steam condenser. • This combine cycle power plant gives approximately 45% efficiency. • Recent CCPP are designed to give efficiency as high as 58 %.

4. Advantages: • High overall plant efficiency • Low investment cost • Reliability of supply • Small amount of cooling water required • Saving of Fuel • Flexibility of operation • Simplicity of operation

5. Disadvantages: • While the designing of combined cycle power plant, choise of voltage, economic load transfer, system stability should be studied.

6. CCPP in India:

7. TPS in India:

8. Hydro Power Plants in India:

9. Cont…

10. Pressurized Water Reactor (PWR) :

11. Cont… • Enriched Uranium as Fuel • Water is used as coolant & moderator • The water in the primary circuit gets heated by absorbing the fission energy in the reactor core & same energy is given in the heat exchanger to generate the steam. • The water coming out of the heat exchanger is circulated by the pump to maintain the pressure in the circuit in the range of 100 to 130 atm. • The water becomes radioactive when passing through the reactor ; therefore entire primary circuit including heat exchanger must be shielded to protect the operating persons. • The electrical generator coupled with steam turbine generates electrical power.

12. Advantages: • The water which is used as coolant, moderator and reflector is cheap & easily available. • Requirement of control rods are less. • Secondary circuit is not affected by radiation, so normal turbine maintenance technique can be used. • Operation is safe & stable. Disadvantages: • High primary circuit pressure requires strong pressure vessel. • High capital cost. • Corrosion problem.

13. Boiling Water Reactor(BWR) : • Enriched Uranium is used as fuel and water is used as coolant. • In this type of reactor steam is generated in reactor core itself & this steam is expanded in turbine. • After expansion steam iscondensed in condenser. Feed pump is used to circulate water back into reactor core.

14. Advantages: • The pressure inside the reactor vessel is considerably smaller than P.W.R. • The metal surface temperature is lower than P.W.R. • The boiling water reactor (B.W.R.) is more stable than any other type of reactor. • The thermal efficiency of this reactor is 30 %. Disadvantages: • The steam leaving the reactor is slightly radioactive therefore, light shielding of turbine and piping is necessary. • More safety precautions needed which are costly.

15. CANDU Reactor: • The long form of CANDU is Canadian Deuterium Uranium. • Natural Uranium is used as fuel and heavy water as moderator.

16. Advantages: • No control rods are required, so control is much easier. • Enriched fuel is not required. • A short time is needed to construct the reactor compared with P.W.R. and B.W.R. • Heavy water being good moderator. Disadvantages: • The cost of heavy water is extremely high. • The leakage is major problem. • Very high standard of design, manufacture, inspection and maintenance are required