The document discusses the importance of coal handling plants in providing a continuous supply of coal to power stations. It describes how coal is transported from mines via rail, road or conveyor belt and then handled and stored at power stations. Coal handling plants unload coal, stack it for storage, and reclaim and feed it to boilers. They maintain a minimum 45-day ground stock of coal to ensure uninterrupted coal supply in case of transportation failures. The document also classifies different types of coal and their properties and consumption rates at power stations.
2. Introduction
• Coal is the primary fuel for production of
electricity in our country. The importance and
magnitude of the business of coal handling is
emphasized by the fact that more than 60% of
India’s total installed generating capacity
consists of coal fired stations.
3. Transportation of coal
• Coal is transported from the collieries by the
various methods viz. , by rail, road, aerial rope
way or conveyor belt. After transporting the
coal from coal mines to power station, coal is
required to be fed to the boilers or to be
stored in the storage yard and this is
accomplished with the help of a system of
equipments called coal handling plant.
4. Stock Yard
• When coal transportation system fails it is
essential that coal should be made available
to boilers continuously so that three may not
be stoppage of power. To meet such situation
it is necessary that sufficient stock of coal is
made at the power station so that there may
not be interruption in coal supply to the
boilers.
5. Two main functions
• It is expected to keep a minimum ground stock
of coal to cater to the requirement of the
station for the period of 45 days. Thus besides
unloading the coal received by various mode
of transportation, coal handling plant has to
perform two main functions (i) Stacking and
reclaiming of coal to feed the boilers in case
direct supply from mines fails (ii) To feed the
boilers with the coal directly received from
mines
6. Classification of coal
• Coal is the main fuel of a thermal power
station. Coal is classified as :
• Peat.
• Light
• Bituminous
• Anthracite
7. Peat
• It is the first stage in progress of
transformation of buried vegetation into coal.
It contains high percentage of moisture and
small percentage of volatile matter and
carbon.
8. Lignite
• It is the next stage in the development of
coal. It also contains high percentage of
moisture (30%), but can be dried just by
exposing to air (6%). It can be used as fuel in
pulverized form. Neyveli Power station in
Tamil Nadu is the first power plant in the
country which used lignite as fuel.
9. Bituminous Coal
• It is the most popular form of coal used for all
purpose. It has low moisture content. Sub-
bituminous coal is similar to lignite. It contains
50% less moisture than lignite It also contain
less ash than lignite but is has no caking
power.
10. Semi-bituminous coal
• Semi-bituminous coal is intermediate between
anthracite, and bituminous coal. It has low
percentage of moisture, ash Sulphar and
volatile matter and high percentage of
available hydrogen. It contains 10 to 20 %
volatile matter and 2 to 4 % oxygen.
11. Anthracite
• It is the last stage in the process of
transformation or buried vegetation into coal
and it contains highest percentage of carbon
and low percentage of V.M. (below 8 %). It
burns only at high temperature. The
pulverization of anthracite is very difficult and
costly.
12. Consumption of coal
• A 200 MW unit consumes about 2500 tones of
cal everyday
• Average amount of Bituminous coal required
generally varies fro m 0.5 to 0.6 MT/MWH/hr
A 500 MW unit consumes about 280 Tones of
coal every hour.
