Purpose of coal and ash handling unit :- To transport coal from coal storage to power plant. A large quantity of ash about 10 to 30 % produced in furnace, the removal of ash from boiler furnace is necessary for efficient combustion.
Different activities :-
1. Coal Handling Activity:-
Coal Delivery:- Coal from supply point (mines) is delivered to TPP by dumper or railway or in case of power plant, which are located near sea-shore are delivered by ship.
Coal unloading: It is done by machinery not manually. e.g. With the help of rotary car dumper or crane etc.
Coal Storage: It is desirable that sufficient quantity of coal should be store at generating station. Because large quantity of coal is required for generation. There are two types of storage:
1. Outdoor storage (Dead storage)
2. Indoor storage (live storage)
Preparation of coal: In the plant coal is crushed into small pieces with the help of crusher and breaker. The coal is crushed to 2.5 cm. or less.
Then it is cleaned by passing forced air to remove the dust contain.
Moisture is removed with the help of dryer. The moisture content must be less than 2% after drying operation.
This coal is passed through magnetic separator to separate the iron particles mixed in it.
Now, coal is passed to pulverizing mill.
Coal Weighing: Before sending pulverized coal to the furnace, its weight is taken.
2. Ash Handling Activity:- Handling of ash coming out from furnace is a problem because.
Ash is too hot.
It is dusty.
It contains some poisonous gases Hence before handling it is desirable to quench the ash due to following reasons.
It reduces temperature of ash.
It reduces dustiness.
Handling of ash includes:
Removal of ash from furnace.
Load on conveyer belt.
Deliver to the space where it can be disposed off.
Various methods of disposal of ash: