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| Coal Combustion Products (CCPs) are produced from the
combustion of coal, the principal fuel source for today’s electric energy
needs. The four basic types of coal are anthracite, bituminous, subbituminous
and lignite. Coal ash is produced in electric power plants by the burning of
coal in steam boiler furnaces. The furnace is equipped for continuous combustion
and the coal is injected into the furnace where combustion takes place. The coal
ash, or non-combustible portion of the coal, is collected from the bottom of the
boiler or exits the boiler in the flue gas stream to be captured using dust
collection devices. These residue products include fly ash, bottom ash, boiler
slag, and other clean-coal combustion materials. |
Fly ash has a powdery appearance and fine texture. It feels very much
like talcum powder |
Fly ash for use in portland cement concrete represents the
largest usage for CCPs. One of the first large-volume use of CCPs was by
the U.S. Army Corps of Engineers in construction of the Hungry Horse Dam
near Glacier National Park in Montana in the late 1940s. The Federal
Aviation Administration has created standards which provide for fly ash
use in concrete for airport runways and related facilities. The addition
of coal fly ash produces concrete with improved strength and durability. |
Fly ash concrete supported tower cranes on the grounds of the U.S.
Capitol building during bicentennial renovations. |
Other applications include road base, snow and ice
control, structural fill, waste stabilization, blasting grit, filler in
plastics, paints and metals, absorbing oil spills, roofing granules,
wallboard manufacture, and material for plant growth media. |
| Direct application of fly ash can aid in the
successful establishment of vegetation as part of a reclamation program.
Addition of fly ash to surface soils improves the physical
characteristics of the soil, with the fine material creating a better
graded soil texture. This change improves the water holding capacity of
the soil and better supports vegetation. Fly ash also provides nutrients
and neutralizes acidity. Fly ash typically is added at rates up to four
hundred tons per acre to mine spoils as part of revegetation
programs. |
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his hillside was denuded by emissions from a smelting
operation. CCPs were part of a successful reclamation plan to restore vegetative
growth.
For more information on coal combustion products, contact the
American Coal Ash Association.
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