How does rotary paper sludge dryer treat sludge from paper mill?

In the production process of paper mills, a large amount of paper making sludge is generated every day. This type of sludge has a very high water content, high viscosity, is prone to agglomeration, occupies a large area, and needs to be properly disposed of. Whether it is landfill treatment or resource utilization, the first step is to reduce the moisture content of sludge. The traditional sludge dewatering process uses plate and frame filter presses or belt filter presses to reduce the moisture content of sludge through mechanical extrusion. However, the moisture content of the treated sludge is still relatively high (55-65%), and the subsequent transportation cost is expensive, so it is necessary to further reduce its moisture content. The most commonly used way to reduce the moisture content of sludge in paper mills is to use a rotary paper sludge dryer.

Unique structural design of rotary papermaking sludge dryer

Considering that papermaking sludge is different from ordinary grains or mineral powder, it has extremely strong viscosity. Therefore, the device has undergone special structural optimization:

Anti sticking design: The cylinder body is equipped with a special "rotary rake crushing" device. When large wet mud enters, the high-speed rotating rake plate will crush it into small particles, avoiding the formation of a "mud shell" on the cylinder wall and ensuring that hot air can penetrate the material layer.

Layout of material lifting plate: A spiral distribution of lifting plates is used to continuously lift and drop materials, forming a dense "material curtain" and maximizing the heating area.

Working principle and process of rotary papermaking sludge dryer

1. Feeding and preheating

Wet sludge enters the dryer through a belt conveyor. Due to its extremely high moisture content, the material appears as a slurry with poor fluidity.

2. High temperature evaporation (downstream section)

The material enters the high-temperature zone and comes into contact with the hot gas flow (usually>600 ℃). The water evaporates rapidly, expands in volume, and is thrown into the air by the lifting plate, forming a misty water curtain.

3. deep drying (counter current/reciprocating section)

After initial dehydration, the material enters the low-temperature zone. At this point, the high-temperature exhaust gas is used for secondary drying, and granulation is completed during this process to turn the sludge into loose particles.

4. Discharge and dust removal

Dry mud with a standard moisture content (10% -20%) is discharged from the other end. The exhaust gas is purified by a dust collector and discharged to achieve zero pollution.

Using a rotary dryer to dry papermaking sludge can achieve 24-hour fully automated continuous operation, with high thermal efficiency and good drying effect. The finished product is in granular form, which is convenient for transportation and subsequent deep processing. The rotary paper sludge dryer effectively solves the problem of sludge treatment in paper mills, not only protecting the environment but also promoting the reuse of resources.