Special dryer for hollow paddle sludge

Feed. The dewatered sludge with solid content of 15%-30% is sent to the inlet of the dryer by screw conveyor, sometimes according to the nature of the sludge. Select whether to premix the screened fine dried sludge with the sludge to be dried.

Heat source generation. Hot steam or hot oil can be used as the heat source for heat exchange. The temperature of general hot fluid is 180 ℃ -200 ℃. The thermal medium is respectively introduced into the hollow dryer shell, rotating shaft blades and other heated metal surfaces that contact with the sludge for heat exchange.

Sludge drying. The heated metal surface is in uniform contact with the sludge. The heated sludge evaporates the water in the sludge. Along the axial length of the dryer, the steam generation will experience two stages: constant evaporation rate and low evaporation rate. The sludge drying will undergo four steps: plasticization, plastic breaking, blocking and particle. The temperature of the sludge is rising rapidly, stably and rapidly. Finally, the temperature of the outlet sludge is 100 ℃-

When the temperature is about 10 ℃, the solid content of the exported sludge reaches more than 90%.

Cooling screening. There are two cooling methods: direct cooling and indirect cooling. The two methods enter the fine grid for screening or reach the required dry sludge shape after passing through the molding machine.

Condensation recovery. The hot steam in the dryer is sent to the condenser for condensation treatment, the condensed solvent is recovered, the non condensable gas is sent to the boiler for heating into a heat source, and the condensed water is returned to the sewage treatment plant.