1. VARIABLE EFFECTING EFFICIENCY OF RANKINE,REHEAT,REGENERATIVE CYCLE

2. Rankine Vapor Cycle p v 1 6 5 4 3 2 p1 p2 S 4 6 1 2 3 T s 1 6 5 4 3 2

3. From the equation of the efficiency of rankine cycle, the factors affecting the efficiency of rankine cycle are:

4. 1. － Pressure of Steam, Turbine Inlet3 4 5 5’ 1’ 1 2 2’
－Unchange
Two Cycles: ①
② 3-4-5’-1’-2’-3

5. 3 4 5 5’ 1’ 1 2 2’
Disadvantages: 1.
decrease the turbine efficiency and
erodes the turbine blades.
Increase of requirements on pressure
vessels and equipment investment. 2.

6. 2. － Temperature of Steam, Turbine Inlet3 4 5 1 1’ 2’ 2 6
－Unchange
Two Cycles: ①
② ’-2’-3

7. Advantages: i ii Disadvantages: it decreases the moisture content3 4 5 1 1’ 2’ 2 6
Advantages: i ii
it decreases the moisture content
of the steam at the turbine exit.
Disadvantages:
Superheating temperature is limited
by metallurgical considerations.

8. 3. － Condenser Pressure, Turbine Exit4 5 1 3’ 2’ 2 6 4’
－Unchange
Two Cycles: ①
② 1-2’-3’-4’-5-6-1

9. i Disadvantages: ii i Condense pressure is limited3 4 5 1 3’ 2’ 2 6 4’ i
Disadvantages:
i Condense pressure is limited
by the sink temperature.
ii It increases the moisture
content which is highly
undesirable. ii

10. Reheat Cycle
Allows us to increase boiler pressure and temperature of the steam entering into the turbine without problems of low quality at turbine exit.
The erosion and corrosion difficulties due to the presence of water particles in the steam can be avoided by reheating of steam, because the steam becomes dry after reheating.
In reheating, whole steam is extracted from suitable point in the turbine and is reached with the help of the flue gases in the boiler furnace.

11. 3 c 2 a 1 5 4 6 b

12. Regeneration
Preheats steam entering boiler using a feedwater heater, improving efficiency
Also deaerates the fluid and reduces large volume flow rates at turbine exit.

13. Boiler
Turbine
Regenerator
Condenser
Mixing Chamber
Pump II
Pump I 1 2 7 3 4 5 6
3(4) 2 7 1 6 5
1kg
akg
(1-a)kg T s

14. A more complicated cycle…

15. THANK YOU