The document discusses different thermodynamic cycles used in steam power plants, including Rankine, reheat, and regeneration cycles. It provides diagrams and equations to analyze each cycle. The Rankine cycle involves boiling water to steam, expanding the steam in a turbine, condensing it back to water, and pumping the water to high pressure. Both the reheat and regeneration cycles improve the Rankine cycle efficiency by adding additional heat transfer processes. The reheat cycle reheats steam after the high-pressure turbine, while regeneration uses feedwater heating to preheat water before boiling.

1. Prepared By:- Nisarg Amin
Topic : Engineering Applications
Of
Thermodynamics

2. Basic component of steam power
cycle:
1.Steam boiler : convert water in to steam
2.Steam turbine : convert kinetic energy of
steam in to mechanical energy
3.Condenser : heat transfer device
4.Feed pump : increase the preasure of
condansate steam.

3. Rankine cyclcle:
Process 2-3 in boiler : heat supplied (Qi)=(h3-h2)
(since work done is zero)
Process 3-4 in turbine: turbine work (Wr)=(h3-h4)
(since heat transfer is zero)
Process 4-1 in condenser : heat rejected to cooling
water,(Qr)=(h4-h1) (since work done is zero)
Process 1-2 in feed pump:pump work (Wp)=(h2-h1)
(since heat transfer is zero)

4. Flow diagram of rankine cycle

5. P-V ,T-S ,and h-s diagram of rankine
cycle

6. Thermal efficiency of rankine cycle
Efficiency(ή)=shaft work/heat supplied
=[(h3-h4)-(h2-h1)]/(h3-h2)
=[(h3-h4)-(h2-h1)]/[(h3-h1)-(h2-h1)]
if pump work is neglected than,
Efficiency(ή)=(h3-h4)/(h3-h4)
Steam rate(S.R):=3600/shaft speed

7. Flow diagram of reheat cycle

8. T-s and h-s diagram of reheat cycle

9. Analysis of reheat cycle
The thermal efficiency of reheat cycle is given by,
Efficiency(ή)=shaft work/heat supplied eqn-1……….
shaft speed (Ws)=(Wt for L.P. +Wt for H.P.)-Wp
=(h3-h4)+(h5-h6)-(h2-h1)
Heat supplied(Qi)=heat supplied in boiler +heat supplied in
reheater
=(h3-h2)+(h5-h4)
put the value of Ws and Qi in eqn-1….than we
get
Efficiency(ή)=[(h3-h4)+(h5-h6)-(h2-h1)]/[(h3-h2)+(h5-h4) ]

10. Advantages of reheat cycle
Improves thermal efficiency the plant since the
additional heat is supplied at higher mean
temperature.
It increases the network output of the turbine.
It reduces the steam rate per KWh.
It improves the condition of the steam at exhaust
of the L.P. turbine so that tendency of blade erosion
caused by the liquid particles in the L.P. turbine is
reduced. The desirable maximum moisture is steam
is considered to be about 10 to 12%.

11. Disadvantages of reheat cycle
To increase the cost and size of plant due to
inclusion of reheater and its long piping.
Increase the size of condenser based on
unit mass flow of steam due to improved
quality of steam of exhaust from L.P. turbine.

12. Flow diagram of regenration cylce

13. T-s diagram analysis of regeneration
cycle
It is obvious that the
efficiency of regenerative
cycle will more than rankine
cycle because of the
increased mean effective
temperature during heat
addition process , while the
mean temperature of heat
rejection process remain
same,

14. Advantages of regeneration cycle
It increases the thermal efficiency of the
plant.
The temperature stresses in the boiler are
reduced due to decreased range of working
temperatures.

15. Disadvantages of regeneration cycle
Steam rate increases due to reduced work done
per kg of steam flow from boiler . Therefore ,for a
given capacity of the power plant output the boiler
size increases.
Though the heat rejected in the condenser
reduces for unit flow of steam , however , the size
of condenser almost remains the same for a given
capacity of power plant.
The cost of the plant increases.

16. Mollier diagrams