The working principle is: the dewatered sludge enters the mixer from the sludge funnel, and the part of the dried sludge is fully mixed according to the proportion, so that the solid content of the dry and wet mixed sludge reaches 50-60%, and then The screw conveyor is transported to the three-channel drum dryer.

The hot air flow entering the drum and the same end is 1.2-1.3m/s and the temperature is about 700℃. The hot air is mixed and heated. After about 25min of treatment, the dried sludge is conveyed by a screw with a metering device. The machine is sent to the separator, where the hot and humid gas discharged from the dryer is collected for thermal recycling, and the polluted malodorous gas is sent to the biological filter for treatment and meets the environmental protection requirements. The dry gas discharged from the separator The particle size of the sludge can be controlled, and then the sludge particles that meet the requirements are sent to the storage bin for processing through the filter.

The dryness of the dried sludge is 92% or higher. The diameter of the dried sludge particles can be controlled within 1-4mm, which mainly considers the possibility of using dried sludge as fertilizer or landscaping. The fine dry sludge is sent to the mixer to mix with the wet sludge and sent to the drum dryer. The burner used to heat the drum dryer can use biogas, natural gas or hot oil as fuel.

The separator separates the dried sludge and water vapor. The water vapor carries almost all the heat consumed when the sludge is dried, and this part of the heat needs to be fully recycled. Therefore, the water vapor has to pass through the condenser. The condenser cooling water inlet temperature is 20°C, and the outlet water temperature is 55°C. The cooled gas is sent to the biofilter for treatment and discharged after it reaches the emission standard.

The characteristics of the drying system are: operating in an oxygen-free environment, no dust is generated, the dried sludge is granular, the particle size can be controlled, and the gas recycling design reduces the cost of exhaust gas treatment.