Power Plant Engineering

Chapter 4Chapter 4Chapter 4Chapter 4Chapter 4

Steam Power PlantSteam Power PlantSteam Power PlantSteam Power PlantSteam Power Plant

4.1 Introduction

Steam is an important medium of producing mechanical energy. Steam has the advantage that, it
can be raised from water which is available in abundance it does not react much with the materials of the
equipment of power plant and is stable at the temperature required in the plant. Steam is used to drive
steam engines, steam turbines etc. Steam power station is most suitable where coal is available in abun-
dance. Thermal electrical power generation is one of the major method. Out of total power developed in
India about 60% is thermal. For a thermal power plant the range of pressure may vary from 10 kg/cm^2 to
super critical pressures and the range of temperature may be from 250°C to 650°C.

The average all India Plant load factor (P.L.F.) of thermal power plants in 1987-88 has been
worked out to be 56.4% which is the highest P.L.F. recorded by thermal sector so far.

4.2 Essentials of Steam Power Plant Equipment

A steam power plant must have following equipments :

storageAsh handlingAsh

plant

handlingCool

plant

storageCoal

preheaterAir

Air Econo-miser

To Chimney

gasesFlue

Air

Flue gases

Feed water

Superheater

Mainvalve

gasesFlue Superheated steam

Steam

Boiler

High pressureheater

feed pumpBoiler

Low presserheater

water pumpCirculating

Condensateextraction

pump

Condens-er

Exhauststeam

Tu r b i n e

Cooling tower

River or Canal

Generator

3-phase supply

Fig. 4.1. Steam Power Plant.