Methods and Systems For Dewatering Bottom Ash Using A Remote Submerged Scraper Conveyor

A bottom ash dewatering system for a boiler comprising:

• a submerged scraper conveyor located remotely from the boiler, the submerged scraper conveyor comprising a horizontal section comprising first and second side walls and first and second ends, a dewatering incline section adjacent a first end of the horizontal section, and a conveyor running through the horizontal and dewatering incline sections;
• an ash hopper located under the boiler;
• a slurry discharge pipe adapted to deliver a wet ash slurry from the ash hopper into the horizontal section of the submerged scraper conveyor;
• and
• an overflow trough system comprising a first trough section adjacent the first wall of the horizontal section, a second trough section adjacent the second wall of the horizontal section opposite the first trough section and one or more trough connecting sections between the first trough section and the second trough section;
• wherein the horizontal section of the submerged scraper conveyor has a water line defining a level above which water in the horizontal section will overflow into the overflow trough system;
• and
• wherein the conveyor runs through the horizontal section at a level below the water line.

A method of conveying bottom ash generated from combustion in a furnace, the method comprising:

• combining the ash with water to form a slurry;
• pumping the slurry to a submerged scraper conveyor located remotely from the furnace, the submerged scraper conveyor comprising:
• a horizontal section;
• a dewatering incline section;
• a conveyor running through the horizontal and dewatering incline sections;
• an overflow trough system;
• and
• a weir system located between the horizontal section of the submerged scraper conveyor and the overflow trough system;
• wherein the horizontal section contains water and has a water line defining a level above which water in the horizontal section will flow through the weir system and into the overflow trough system, wherein the conveyor runs through the horizontal section at a level below the water line and wherein the slurry is pumped into the horizontal section of the submerged scraper conveyor;
• and
• conveying the slurry from the horizontal section up the incline section to dewater the slurry;
• wherein the slurry is pumped from the furnace to the submerged scraper conveyor at a rate of 1,000 to 10,000 gallons per minute (227 to 2,271 m3/hour);
• and
• wherein the submerged scraper conveyor comprises at least 1 linear foot of weir for each 30 gallons per minute of slurry flow rate;