摘要 |
Sludge is dried in a dryer and burned in a furnace, the dryer being heated by heat from the furnace using a heat exchanger so that contaminants from furnace hot gas do not pass into the dryer. Gas given off from the dryer is in part mixed with fresh air and circulated back to the dryer, and is in part delivered to the furnace for combustion, being first cooled to reduce its moisture content. Gas from the furnace is also treated to remove solids, and is cooled. Water used as coolant is heated by the gases and used for anaerobic digestion of sludge, producing gas for combustion in the furnace. Dry sludge from the dryer is broken up and mixed with wet sludge entering the dryer to obtain desired sludge grain sizes.
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