Dry Slag Remover Bottom Ash Conveyor Achieving No - Water Discharge

Dry slag remover (Dry slag extractor)Its material is Stainless Steel 304 or 316:

Working Principle

Under normal boiler operation condition, the hot slag (about 850℃) fell from the bottom ash hopper will be discharged by the bottom ash discharge device to the belt of the steel band conveyor, and move slowing together with belt. Due to the negative pressure of boiler, the cold air will flow into the casing of the conveyor through the air vents to cool the hot bottom ash on the belt and make it re-burn gradually, achieving the heat exchange between the coal air and the hot bottom ash, and then the cold air will absorb the sensible heat of the ash and the heat released by the re-burning ash, and the air temperature will increase to 400-500℃ before entering the boiler furnace. The bottom ash will be conveyed and cooled down to less than 200℃ on the slag conveyor, and then delivered to the follow-up conveying device.

System Composition

Steel band conveyor is the kay equipment of the dry slag conveying system, installing at the outlet of the boiler bottom slag discharge device. The conveyor is made up of steel band, chain scraper (cleaning chain), and the casing. The steel band consists of high temperature resistant conveying belt, supporting roller, under roller, side limit roller, driving mechanism, and tension mechanism. The scraper cleaning chain consists of chain, scraper, under roller, driving mechanism, and tension mechanism. There are one adjustable air inlet at both side of the casing, and two air inlet holes at the top of the casing, which can adjust the air according to the generated slag quantity. There are one access doors at both ends of the conveyor used for short time maintenance of the steel band and cleaning chain. The hydraulic tension mode is used for the conveyor belt and the chain scraper, the pressure supply is shared with the hydraulic crusher, and the accumulator tank is available. The function of the steel band conveyor is to continuously receive and sent out high temperature boiler bottom ash, and make the ash have further burning and cooling during the conveying. The conveying speed can be adjusted in accordance with the bottom ash quantity.

System Advantages:

The steel band slag conveyor can make use of the negative pressure of the boiler to suck cold air to cool the slag during the conveying process, achieving no-water discharge, simplifying the slag discharge system, and avoiding the disadvantages of the hydraulic slag system as too many equipment and large occupied area.

The slag burns again during the cooling process, and the generated heat is be absorbed by the air which is 1% of the total air flow entering the furnace, making the temperature of the air increase by 400℃, which has improved the boiler efficiency.

The dry slag can be used in many ways such as pave a road and make bricks, which has made more economic benefits for the power plant.

The operation of the dry slag discharge and conveying system is simple and maintenance is convenient.