Generation of electricity in
a coal-fired steam station is similar to a nuclear station. The difference is
the source of heat. The burning of coal replaces fissioning,
or splitting , of uranium atoms as the
source of heat. The heat turns water to steam in steam generators. The steam is
then used to drive turbine generators.
1. Firebox
Before the coal is burned, it
is pulverized to the fineness of talcum powder. It is then mixed with hot air
and blown into the firebox of the boiler. Burning in suspension, the coal-air
mixture provides the most complete combustion and maximum heat possible.
2. Boiler
Highly purified water, pumped
through pipes inside the boiler, is turned into steam by the heat. At
temperatures of up to 1,000 degrees Fahrenheit and under pressures up to 3,500
pounds per square inch, the steam is piped to the turbine.
3. Turbine|Generator
The enormous pressure of the
steam pushing against a series of giant turbine blades turns the turbine shaft.
The turbine shaft is connected to the shaft of the generator, where magnets
spin within wire coils to produce electricity.
4. Condenser
After doing its work in the
turbine, the steam is drawn into a condenser, a large chamber in the basement
of the power plant. The condenser is an important part of a steam-electric
unit, whether nuclear or coal-fired. This device condenses the steam leaving
the turbines back into water so that it can be used over and over again in the
plant. This essential cooling process requires large quantities of water; thus,
most steam-electric stations are located on lakes or rivers.
5. Condenser Cooling Water
Millions of gallons of cool
lake water are pumped through a network of tubes that runs through the
condenser. The water in the tubes cools the steam and converts it back into
water. After the steam is condensed, it is pumped to the boiler again to repeat
the cycle.
Coal Fired Power Plant Schematic Diagram: