A simplified submerged chain conveyor system for handling ash produced by large-scale coal fired boilers. The system incorporates an endless chain conveyor system moving a coal/ash aqueous mixture within a conveyor segment having a hydraulically closed duct. The system is adapted for retrofit applications of existing coal-fired boiler installations. In each embodiment the chain conveyor elevates the aqueous ash solution to dewater the ash. In several embodiments the boiler ash hopper is partially flooded with water and the system moves the ash mixture through a water column to the dewatering section. In one embodiment the ash mixture is not submersed but is subjected to water sprays before reaching the dewatering section. Great flexibility is provided in locating and positioning the conveyor system. One unit may be implemented to provide ash handling for multiple boilers. Embodiments are described operable in continuous or batch mode processes.

A remote submerged chain conveyor system separates particles from a coal ash/water slurry from remotely located boiler units. A tank forms an ash holding section, a dewatering section, and an ash settling section. The ash holding section receives the slurry with first and second opposite ends. The dewatering section dewaters the slurry. The settling zone is an elongated trough connected with the ash holding section at one end with a discharge drain trough at near an opposite end. The tank sections are in a generally linear arrangement. A drag chain moves along the ash settling conveying the particles settling from the slurry to the dewatering section opposite to a net flow of water. A flocculant supply line upstream of the ash settling section configured for adding a flocculant promoting an agglomeration of particles into flocs. The flocculant supply line is located in a mixing section with an agitator.

The present invention discloses a resource recovery method and a resource recovery system of desulfurized ash. The resource recovery method comprises: washing desulfurized ash with water, and performing solid-liquid separation to obtain solid residues rich in calcium sulfite and calcium sulfate and a solution rich in calcium hydroxide; preparing the solution into desulfurized slurry; and roasting the solid residues under the action of a reducing agent to obtain flue gas rich in sulfur dioxide and residues rich in calcium oxide. Therefore, the recovery of sulfur and calcium in the desulfurized ash is realized, and no solid waste, liquid waste, gas waste, etc. are produced in the process.

A simplified submerged chain conveyor system for handling ash produced by large-scale coal fired boilers. The system incorporates an endless chain conveyor system moving a coal/ash aqueous mixture within a conveyor segment having a hydraulically closed duct. The system is adapted for retrofit applications of existing coal-fired boiler installations. In each embodiment the chain conveyor elevates the aqueous ash solution to dewater the ash. In several embodiments the boiler ash hopper is partially flooded with water and the system moves the ash mixture through a water column to the dewatering section. In one embodiment the ash mixture is not submersed but is subjected to water sprays before reaching the dewatering section. Great flexibility is provided in locating and positioning the conveyor system. One unit may be implemented to provide ash handling for multiple boilers. Embodiments are described operable in continuous or batch mode processes.

Remote submerged scraper conveyor (SSC) consists of a conventional SSC modified to include a slurry processing system, which allows it to be located remotely from associated boilers at or slightly above grade level rather than directly under a boiler like a conventional SSC. The slurry processing system includes a pair of overflow troughs 34 and associated weirs located exterior to and along the top edge of each side of the horizontal section of the SSC and an underflow baffle, which extends from a position above the water line down into the horizontal section of the SSC below the water line. The slurry processing system allows the Remote SSC to receive a high volume wet ash slurry discharge via a slurry discharge pipe conventionally sent to an ash pond or a tall dewatering bin system.

A resource recovery method and a resource recovery system of desulfurized ash. The resource recovery method includes washing desulfurized ash with water, and performing solid-liquid separation to obtain solid residues rich in calcium sulfite and calcium sulfate and a solution rich in calcium hydroxide; preparing the solution into desulfurization slurry; and roasting the solid residues under the action of a reducing agent to obtain flue gas rich in sulfur dioxide and residues rich in calcium oxide. Therefore, the recovery of sulfur and calcium in the desulfurized ash is realized, and no solid waste, liquid waste, gas waste, etc. are produced in the process.