Steam Power Cycles

     Steam power plant is used to generate electricity by using steam as the working fluid. A simple power plant consists of a boiler, turbine, condenser and a pump or compressor. Heat is supplied to the boiler and then heats the water to generate steam. This steam is used to rotate the turbine which powers the generator. Electrical energy is generated when the generator windings rotate in a strong magnetic field. After it passes through the turbine, the steam is condensed in a condenser and become a liquid. The liquid is pressurized by the pump and going back to the boiler.

   Block diagram for steam power plant cycle.

Two major cycle is the Carnot cycle and Rankine cycle.

1) Carnot Cycles - For all heat engines, the most efficient cycle is the Carnot cycle. The Carnot cycle consist  two reversible isothermal and two reversible isentropic processes.

      

     

T-s diagram for Carnot Cycle.

Process in this cycle are:

4-1 (boiler)       : Evaporating process at constant pressure and  
                            constant temperature (isothermal process)

1-2 (turbine)     : Expanding process  isentropically from high           
                           pressure and temperature to low pressure  and  temperature

2-3(condenser):Condensation process at constant pressure  and   
                        constant temperature   (isothermal  process)

3-4 (compressor): Compression process  isentropically from low pressure and temperature to high  

                             pressure and temperature

2) Rankine Cycles

T-s diagram for rankine cycles



4-5-1 (boiler)     : Heating process at constant pressure 

1-2 (turbine)     : Isentropic expansion  from high pressure and temperature to low pressure  

                            and temperature

2-3 (condenser) : Cooling process at constant pressure 

3-4 (pump)        : Isentropic compression from low pressure and temperature to high pressure 

                             and temperature

So do you noticed the difference between these cycles? Alright, by the end of this page, hopely students will be able to explain the T-s diagram of these cycles.. Good Luck!!


REFERENCE:

1. NOTA TERMODINAMIK 2 POLITEKNIK

2.

Title	Power Plant Engineering
Authors	A. K. Raja, Amit Prakash Srivastava
Publisher	New Age International, 2007
ISBN	8122418317, 9788122418316

3.