BOTTOM ASH HANDLING SYSTEM

The fly ash which is discharged from the bottom ash discharged from the bottom in a boiler furnace (clinker ash) is cooled, it’s picked out and the equipment from which this is conveyed to a storage place is called bottom ash handling system.

A submerged scraper conveyor system is used at Europe mainly.

There are little make-up water amount and power consumption, and this system is low in cost and is an economical way.

But there is a problem in the reliability and the maintenance because it’s mechanical.

A system suitable to lower the cost.

A Hydraulic Conveying System with a jet pump is popular by Japan and U.S..

This is because practical use including maintenance is easy and highly reliable compared with the submerged scraper conveyor system.

But, when using a jet pump, there is a lot of quantity of water and the power to use a high pressure water pump is big also a noise is about 110 dB of violence, so it isn’t desirable as the operational environment.

So we paid attention to an ash pump system for the purpose of canceling the fault of both systems and utilizing the merit.

And we advanced research and development and succeeded in commercializing.

This system is working at a lot of power plants because the quantity of water and the power are little, and equipment is compact and practical use is convenient.

	submerged scraper conveyor system	Hydraulic Conveying System	ash pump system
Diagram
Outline	Bottom ash falls in the installed submerged scraper conveyor under the boiler furnace, and mixes with water and is cooled. Ash is separated from water at the inclination part of a conveyor. This is broken by a clinker crusher and it’s stored in an ash bunker using Chen conveyor or a belt conveyor. This ash is carried at a track.	The ash discharged under the clinker hopper is crushed by a clinker crusher. That’s conveyed to dehydration tack by the waterpower using a jet pump. Dehydrated ash is carried at a track. After the ash handling water from dehydration tack made the SS density fall to less than 500 ppm by an ashy precipitator, it’s utilized in a cycle via a water tank.	The ash discharged under the clinker hopper is crushed by a clinker crusher. That’s conveyed to dehydration tack by the waterpower using a jet pump. Dehydrated ash is carried at a track. After the ash handling water from dehydration tack made the SS density fall to less than 500 ppm by an ashy precipitator, it’s utilized in a cycle via a water tank.
Feature	Operation — Continuous There is little utility amount of consumption. There are a lot of wear parts in equipment, and maintenance is complex. It’s running continuously, so it’s difficult to repair a running breakdown.	Operation — Intermittent The setting area under the furnace is small, but tanks and ponds is necessary. Power costs necessary for ash transportation are high. Because it is big, a noise level of the jet pump has a problem with work environment with 110db degree. The maintenance is relatively easy.	Operation — Intermittent The setting area under the furnace is largish. A noise level of the Ashe pump is 85db degree, and the work environment is good. Abrasion measures are necessary for the ash pump.
use	water — about 0.5t / ash 1t electric power —– about 10kWH / ash 1t	water — about 1t / ash 1t electric power —– about 24kWH / ash 1t	water — about 1t / ash 1t electric power —– about 18kWH / ash 1t