1. Cogeneration & Combined Cycles
Mechanical Engineering Department
ME332 Operation and Management of Power Plants
Cogeneration & Combined Cycles
Prof. Osama A El Masry

2. An Ideal Cogeneration Plant
(Fig. 9-21)
Prof. O. El Masry

3. Schematic and T-s Diagram for
Cogeneration Cycle
(Fig. 9-23)
Prof. O. El Masry

4. Combined Cycles
The overall thermal efficiency of a power plant can be increased by using binary cycles or combined cycles.
A binary cycle is composed of two separate cycles, one at high temperatures (topping cycle) and the other at relatively low temperatures.
The most common combined cycle is the gas-steam combined cycle where a gas-turbine cycle operates at the high-temperature range and a steam-turbine cycle at the low-temperature range.
Prof. O. El Masry

5. Mercury-Water Binary Vapor Cycle
(Fig. 9-24)
Prof. O. El Masry

6. Combined Cycles
The gas-steam combined cycle uses a gas-turbine cycle operating in a high-temperature range and a steam-turbine cycle in a low-temperature range.
Steam is heated by the high-temperature exhaust gases leaving the gas turbine.
Combined cycles have a higher thermal efficiency than the steam- or gas-turbine cycles operating alone.
Prof. O. El Masry

7. Combined Gas-Steam Power Plant
Prof. O. El Masry

8. (Heat Recovery Steam Generator)
HRSG
(Heat Recovery Steam Generator)

9. Types of HRSG 2 bar  20 bar 1 ton/h  10 ton/h up to 180 bar

10. Configurations of HRHG
Evaporator section

11. Superheater section :

12. Economizer section :
Economizer designs would normally follow along with the evaporator type that is being used and be similar in design to the superheater. The configurations would be similar to the ones shown above for the superheaters

13. Preparing a flow schematic for the HRSG :
Pinch point .
Approach point .

14. Single pressure :