I. Product Overview

Low Temperature Sludge Dryer

Sludge is the waste solid generated in the process of waste water treatment. With the development of domestic waste water treatment industry and the progressive improvement of total capacity of WWTP, the sludge capacity is also increased. The cost of infrastructural of normal scale WWTP accounts for 20%-50% total ones’.

Except a great quantity of organic and rich nutrients such as nitrogen and phosphorus, the sludge also contains such poisoned contents as hard metal, pathogen and parasites. The disposal of sludge plays a more important role in protecting sludge from causing second pollution and guaranteeing a normal operation and treatment effect of WWTP.

Low temperature drying system applies to dry the dewatered sludge cake after treatment of filter press break the cell way by spectrum technology, and then help the water eliminate outside from the creature cell successfully. Sludge cake dry the sludge by the circle movement of the heated and dried air that is injected into the system , meanwhile, the wet air is dried by the cooling system on the top of sludge holding tank, after condensation, the treated air will inject into drying room after secondary heating. Closed-loop drying system will not discharge the waste air.

Overview on drying technology
The injected low temperature air dry the sludge with a circle way. Through the sludge layer, the dried air (20% r.H) that is heated up to 50℃ generate wet air (30℃, 99%r.H) which condensate and remove the water on the dryer and then heat the air flow again on the condenser. The dried air moves circularly in the system,, and dried air flow moves in the closed-loop, and the wasted is removed during the water condensation, so the stench prevention device is no need.

II.  Process flow

1, Feeding: Dewatered sludge with a water rate of 80%-86% is convoyed to dryer’s feeding inlet by screw or belt conveyor.

2, Heating: To use steam or heat transfer oil as heat source, heat carrier (steam or heat transfer oil), whose temperature is 120-230℃, will evaporation desperate into two phases: constant evaporation rate and low evaporation rate.

3, Sludge drying: Heated metal cover contact the sludge uniformly to heat and evaporate sludge, and along the shaft of dryer, steam.

4, Waste steam treatment: Waste steam treatment applies spray tower and active oxygen waste gas purification equipment to make the exhausted steam achieve the effect of dust removing and deodorization and be qualified for the discharge standard.

III. Application in organic and inorganic sludge drying for such industry as printing and dyeing, thermal electricity,paper making, leather printed circuit board.