Coal-fired power plants are classified into 2 boiler types, depending on the fuel used. One is Pulverized Coal Boiler, PC boiler using coal particles, the size of which is 200 Mesh. And the other is Circulating Fluidized Bed Coal Boiler or CFBC boiler utilizing a wide range of fuels, including high sulfur, low sulfur, bituminous/anthracitic coals. In coal-fired power plant, they crush coal with the pulverizing mill into less than 200 Mesh and inject the crushed coal into the furnace at a high speed together with hot air.  The floating powder is instantly burned over the temperature range of 1500 ± 200 which is above the melting point of the most minerals contained in the coal. The remaining material after the combustion is called coal ash. In case of anthracite, 26-50% of the coal remains, and as for bituminous coal, about 8-15%. The ashes are divided into bottom ash and fly ash, depending on the place they are gathered at. The ashes that are found at the lower part of CFBC Boiler Hopper are called Bed Ash.. Recently, lignocellulosic biomass-fired boiler is actively reviewed as a new type of thermal boiler in addition to coal-fired boiler.

It is reused as artificial lightweight aggregate, which means it is utilized as construction material for lightweight concrete,, soundproof, and thermal insulation, etc..

If 20 ~ 30% Fly Ash is put into cement paste, the workability of the cement paste is improved and the hardening crack is ameliorated. In addition, long-term strength and water tightness are promoted.

Slag and Bed Material falling after staying in the furnace go through Cooler and are cooled, after which they are stored in Storage Silo and then are reused.

Economizer is a device that preheats water supplied to boiler by utilizing the remaining heat of the combustion gas from boiler. The combustion gas flowing here exchanges heat with boiler water supply device and the larger particles of the ash are automatically collected. The finer particles flow to Air Preheater through Duct. The ash gathered in Main Hopper is discharged and is temporarily stored in the Aux. Hopper, and is discharged cyclically to be transported to Fly Ash Silo by Ejector or Pressure Vessel

Fly Ash collected by electrical dust precipitator is temporarily stored in Hopper and then is transported to Fly Ash Silo by low pressure or high pressure transport method using Blower or Air Compressor.

It is a device to send back Fly Ash stored in Fly Ash Silo into the furnace by using head-air apparatus of Blower and utilizing Ejector, in order to improve the efficiency of the boiler.