What is bottom ash hopper?

General Information. As described, a wet bottom ash hopper is a water-filled steel tank with a protective lining used to collect bottom ash and slag from a steam-generating boiler that uses coal as its main source of fuel. The coal ash and slag fall into the water-filled ash hopper from the furnace above.

What can be done with bottom ash?

Bottom ash is used as construction and railroad fill material, abrasive blasting grit, granules on asphalt roofing shingles, aggregate for concrete and masonry blocks, substitute for sand for traction on icy roadways, and soil amendment to increase permeability.

Which method is used for the bottom ash collector?

Ash recycling Bottom ash can be extracted, cooled and conveyed using dry ash handling technology. When left dry the ash can be used to make concrete, bricks and other useful materials.

What is the difference between bottom ash and fly ash?

Fly ash particles are the lightest kind of coal ash—so light that they “fly” up into the exhaust stacks of the power plant. Bottom ash is the coarser component of coal ash, comprising about 10 percent of the waste. Rather than floating into the exhaust stacks, it settles to the bottom of the power plant’s boiler.

Why is bottom ash bad?

Broadly speaking, coal ash is a pollutant, and it contains acidic, toxic, and radioactive matter. The EPA found that significant exposure to bottom ash and other components of coal ash increases a person’s risk of developing cancer and other respiratory diseases.

Is there a difference between fly ash and bottom ash?

The fine particle ash that rises up with the flue gases is known as fly or flue ash while the heavier ash that does not rise is called bottom ash; collectively these are known as coal ash. Fly ash produces a strong, durable concrete that is resistant to harsh chemicals.

Is bottom ash toxic?

Bottom ash not quite as useful as fly ash, although power plant owners have tried to develop “beneficial use” options, such as structural fill and road-base material. This isn’t a good idea, because the bottom ash remains toxic when recycled.

How is fly ash disposed of?

Worldwide, more than 65% of fly ash produced from coal power stations is disposed of in landfills and ash ponds. Ash that is stored or deposited outdoors can eventually leach toxic compounds into underground water aquifers.

What kind of Ash goes into a wet bottom ash hopper?

Two types of ash fall into a wet bottom ash hopper: coal ash and slag. Coal ash is the residual product left after burning of the fuel and slag, which is the formation of molten, partially fused, or re-solidified deposits on the furnace walls inside the boiler.

How is bottom ash transferred to surface impoundments?

Water impounded bottom ash hoppers, located under the boiler throat are used to store the collected bottom ash and periodically (once or twice per 8 hour shift) the hoppers are discharged and Bottom Ash is hydraulically conveyed to surface impoundments (ash ponds). The ash is pumped utilizing either high pressure jet pumps or slurry pumps.

Where is bottom ash stored in a boiler?

What happens to the ash hopper in a boiler?

An ash hopper is a collection area for ash and slag, and does not contribute to a boiler’s efficiency or energy savings. However, ash-hopper failure requires a boiler to be shut down. A complete ash-hopper replacement (including the plate and lining material) can be expensive and time-consuming.

What is bottom ash hopper? General Information. As described, a wet bottom ash hopper is a water-filled steel tank with a protective lining used to collect bottom ash and slag from a steam-generating boiler that uses coal as its main source of fuel. The coal ash and slag fall into the water-filled ash hopper from…