Pulverized coal fired (PCF) boilers system in the world

Pulverized coal fired (PCF) boilers system in the world

We all know that coal is an important fossil type for the world energy industry, and the coal combustion technology has already needs an improvement for the environment protecting. Now, it is possible with the latest coal fired boiler technology.

Coal-fired water tube boiler systems generate approximately 38% of the electric power generation worldwide and will continue to be major contributors in the future. Pulverized coal fired boilers, which are the most popular utility boilers today, have a high efficiency but a costly SOx and NOx control. Almost any kind of coal can be reduced to powder and burned like a gas in a PCF-boiler.
The PCF technology has enabled the increase of boiler unit size from 100 MW in the 1950's to far
over 1000 MW. New pulverized coal-fired boiler systems routinely installed today generate power at net thermal cycle efficiencies ranging from 34 to 37% (higher heating value) while removing up to 97% of the combined, uncontrolled air pollution emissions (SOx and NOx).

Coal is a heterogeneous substance in terms of its organic and inorganic content. Since only organic particles can be combusted, the inorganic particles remain as ash and slag and increase the need for particle filters of the flue gas and the tear and wear of furnace tubes.
Pulverizing coal before feeding it to the furnace has the benefit that the inorganic particles can be separated from the organic before the furnace. Still, coal contains a lot of ash, part of which can be collected in the furnace.

Burners and layout
Another benefit from pulverizing coal before combustion is that the coal air mixture can be fed to the boiler through jet burners, as in oil and gas boilers. A finer particle is faster combusted and thus the combustion is more complete the finer the coal is pulverized and formation of soot and carbon monoxides in the flue gas is also reduced. The size of a coal grain after the coal grinder is less than 150 mm.
Two broadly different boiler layouts...

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