Know Your Thermal Powerplant.

70% of India's Power is generated by Coal based Thermal Power Plants and yet majority of the general public knows very little about them.

One of the comments that I got related to my previous post about Powerplant(Power Engineers) was how it helped a person know what goes on inside a powerplant. That got me thinking.I know of many people who have no idea of what a thermal powerplant does and how it does what it does.So here I am dedicating an entire post about a thermal powerplant.This is essentially for people who have zero idea about a thermal powerplant.

Q-What does a Thermal Powerplant do?
A-Generate electricity

Q-What is the fuel used?
A-Coal or Gas (This post is about a Coal based Thermal Power Plant)

Let me start with a few pictures.The plant that I will be talking about is a 250MW Unit.

This is a typical Thermal Power Station.What do you see? People who have no idea are, maybe wondering what those buildings house.Let us see, in different pictures some of the  parts.

That building houses the Boiler. A few questions now.

Q.What purpose does a boiler serve?
A.A boiler is where steam is generated.

Q.Why is steam required in a Thermal Power Limited?
A.Because steam is the main driving medium.It is the medium which drives a turbine.

Q.Why does a turbine needs to be driven?
A.Because turbine shaft drives or rotates a shaft inside the generator

Q.Why does a shaft needs to be driven inside a generator?
A.This has a long and a bit complicated answer but lets just get a basic idea.Just know that if you rotate a conductor inside a magnetic field,current begins to flow inside the conductor.So we have a magnetic field already created in a generator.Only thing we have to do is to rotate a conductor in that magnetic field.This is achieved by the generator shaft.This is how current is generated.(The turbine shaft and generator shaft are coupled.When turbine shaft rotates the generator shaft rotates.The turbine shaft is rotated by steam.Steam is produced by a boiler)

Q.How is water heated in boiler to produce steam?
A.By burning coal.

This is the turbine building.It houses the steam turbines and other equipment like pumps etc

These are the chimneys.Now a simple thing needs to be explained.When coal is burned in a boiler furnace,products of combustion are produced.These transfer the heat to water and then they have to be removed.These are sucked out by a set of fans known as Induced draft fans.They suck the gas and eject it out through the Chimneys.

There are other fans like forced draft fans which provide the air needed for combustion in furnace.

Now let me make this clear, coal is not burned as it is.It first crushed into a fine powder, as fine as the talcum powder used in our homes.And Primary Air fans are the fans which lift the coal powder and throw it in the furnace.

This is how coal is transferred to the boiler.From these conveyors coal(size is normal here) falls into the mills( also called crushers or pulverizers) where it is finely crushed.From here,as I mentioned before,Coal powder is lifted by primary air fans and then taken to the furnace where it burns.

Many people draw blank faces when this description comes up.This is nothing but the capacity of a plant.This 1000MW is actually the sum of 4 units of 250MW each. It is generally written as 4x250 MW Power Station. Let me explain what it really means.At any given point of time of the plant's running it produces 250MW of power.So it is not 250MW per hour or per month.
(MW is Mega Watt)

And these are Cooling Towers not chimneys. These are used to cool water.

I hope I have made at least a few things clear for the people who had no idea about a powerplant.If there are any questions I would love to answer them.