Each plant is fired with sub-bituminous coal from the powder river basin PRB see Table 9.3 for coal properties and sized to generate 750 MW of net power. The flue gas temperature exiting the air heaters of all four boilers is 121 C 250 F and the boiler efficiency is 87.2% HHV .
In plants that burn pulverized coal, silos feed coal to pulverizers coal mills that take the larger 5 cm pieces, grind them to the consistency of talcum powder, sort them, and mix them with primary combustion air, which transports the coal to the boiler furnace and preheats the coal in order to drive off excess moisture content.
To fuel the power plant boilers, chain conveyors must first bring coal from the bunkers. Feed belts distributors then transport the coal to the coal mill, where it is ground into dust and blown into the boiler.
This is all controlled by the coal mill or pulveriser, and its associated feeder equipment. Operation of the coal mill can affect the ramp rate of the power station and its ability to handle rapid changes in output. For coal-fired power plants, the response time of the coal mills is critical for the overall reaction time to changing demand.
2.Coal pulverizer/mill system One of the critical power plant components that is relied upon to convert the energy stored in coal into electricity is the coal pulverizer or mill. The coal flow is controlled by the feeder, allowing coal to flow into the pulverizer mill. The pulverized coal and air mixture is then transport to the boiler burner ...
This is the coal mill of thermal power plant.In this is section coal is feed by feeder.This is mainly ball type mill,coal is pulverized by the ball like powder 70%of 200 mesh which is used in ...
ABC OF THERMAL POWER PLANT: MILLS IN A THERMAL POWER. Coal from travelling belt of coal feeder drops in central feed pipe connection between Coal Feeder and Mill . After coal reaches Mill bowl grinding started and hot air also been given to make the pulverised fuel dried enough to classifier chamber.
Similar to the ring and ball mill, the vertical spindle roller mill uses large "tires" to crush the coal. These mills are usually found in utility plants. coal is gravity-fed through a central feed pipe to the grinding table where it flows outwardly by centrifugal action and is ground between the rollers and table.