Bottom ash is produced as a result of burning coal in a dry bottom pulverized coal boiler. Unburned material from a dry bottom boiler consists of about 20 percent bottom ash Bottom ash is a porous, glassy, dark gray material with a grain size similar to that of sand or gravelly sand (Steam 1978). PRB Coal Properties. The Powder River Coal (PRB) is classified as sub-bituminous ranked coal. Unlike higher ranked bituminous and anthracite coals, which have tight pore structures that limit the amount of inherent moisture they could hold, low rank coals like PRB coal have this looser pore structure and additional moisture retention capacity.
Fly Ash. Fly Ash is a byproduct of coal-fired electric generating plants. The coal is pulverized and blown into burning chambers for immediate combustion. Heavier ash particles (bottom ash or slag) fall to the bottom of the burning chamber and the lighter ash particles (Fly Ash) fly out with the exhaust gas, thus the term Fly Ash. Bottom Ash Data. 1.4.1. Density. The bottom ash density is assumed to be 700 kg/m 3 for volume calculations and 1,400 kg/m 3 for structural calculations. 1.4.2. Size Distribution. The bottom ash grain size distribu tion downstream the MAC system is not constant and is dependent on t he secondary mill pulverization efficiency.
iii We Energies Coal Combustion Products Utilization Handbook Chapter 1 Background and History of We Energies Coal 1 Combustion Products (CCPs) Chapter 2 CCPs and Electric Power Generation 9 Electric Power Generation 9 CCPs Generation 10 Properties of Fly Ash 16 Properties of Bottom Ash 20 Properties of Boiler Slag 23. Cinders, Coal ash weighs 0.641 gram per cubic centimeter or 641 kilogram per cubic meter, i.e. density of cinders, Coal ash is equal to 641 kg/m³. In Imperial or US customary measurement system, the density is equal to 40 pound per cubic foot [lb/ft³], or 0.371 ounce per cubic inch [oz/inch³].