Tunnel dryer features:
Our drum dryer has high production capacity and can operate continuously; it features a simple structure, few malfunctions, easy operation, and low maintenance costs, with stable performance. Its wide application range allows for drying powdery, granular, strip, and blocky materials, offering great operational flexibility and allowing for significant fluctuations in output without affecting product quality.
The application scope of the drum dryer:
[Sulfuric Acid Industry]: Ammonium sulfate, sodium sulfide, Angelite powder, urea, oxalic acid, polyvinyl chloride, calcium magnesium phosphate fertilizer, compound fertilizer.
[Food Industry]: Salt, Sugar, Malted Milk Powder, Granulated Sugar
【Minerals】Talc Powder, Bentonite, Titanium Ore, Coal, Manganese Ore, Pyrite, Limestone, Peat
[Other]: Iron powder, flat soybeans, scrap abrasive, matchsticks, wood chips, distiller's grains
Tunnel dryer technical specifications:

Tumble Dryer Overview
Tumble Dryer Mechanical Structure and Working Principle
The direct-heat rotary drum dryer is mainly composed of a heat source, a feeding machine, an inlet machine, a rotating drum, an outlet machine, a blower, a discharge unit, and a power distribution cabinet. After the wet material is dehydrated, it enters the dryer where it is evenly distributed and tumbled by the scraper blades inside the drum, allowing for uniform dispersion of the material and thorough contact with hot air, thereby accelerating the heat and mass transfer in the drying process. During the drying process, under the action of the inclined scraper blades and the hot gas, the material is discharged as finished product at the opposite end of the dryer. It is suitable for the drying of talc powder.
Main Features of the Drum Drying Machine
The drum dryer has a high degree of mechanization, with a large production capacity and can operate continuously.
2. Well-structured, simple design; materials run smoothly through the cylinder with minimal resistance, and operation is user-friendly.
3. Fewer malfunctions, low maintenance costs, and low power consumption.
Wide application range and excellent uniformity in product drying.
High drying temperature, strong drying intensity, low cost of use

Rotary Drum Dryer (Tunnel Dryer) Working Principle:
Dry wet material is conveyed to the hopper by a belt conveyor or a bucket elevator, then it is fed into the charging end through the charging pipeline by the hopper's feeder. The slope of the charging pipeline must be greater than the natural angle of repose of the material to ensure smooth flow into the dryer. The dryer drum is a rotating drum slightly inclined from the horizontal line. Material is added from the higher end, while the heat carrier enters from the lower end, contacting the material in a countercurrent manner; there is also a situation where the heat carrier and material flow together into the drum. As the drum rotates, the material moves under gravity to the lower end. During the forward movement of the wet material within the drum, it is directly or indirectly heated by the heat carrier, allowing the material to dry. Then, it is discharged at the outlet end via a belt conveyor or a screw conveyor. The drum dryer is equipped with scrapers on the inner wall of the drum, which function to lift and scatter the material, increasing the contact surface with the airflow to enhance the drying rate and promote material movement. The heat carrier is typically hot air, flue gas, etc. After passing through the dryer, the heat carrier in the drum dryer usually requires a cyclone separator to collect the material carried in the gas. To further reduce the dust content in the exhaust gas, it should pass through a bag filter or a wet scrubber before being emitted.
Selection of heat carrier for drum dryer:
The heat carrier and the high temperature of the drum dryer are determined by the properties of the solid material being processed, as well as factors such as whether it allows contamination.
If the solid material to be processed is not afraid of high temperatures and is not a finished product, and can be slightly contaminated during the processing, flue gas can be used as a heat carrier, resulting in a higher volume evaporation rate and thermal efficiency. For example, in the drying of imported materials with high moisture content, when the gas inlet temperature is 300 degrees, the volume evaporation rate of the dryer is 5kg/M3/h, with a thermal efficiency of 30%; if the gas inlet temperature is 500 degrees, the volume evaporation rate is 35kg/M3/h, and the thermal efficiency is 70%. Therefore, drum dryers for processing materials such as ore, sand, gravel, coal, and calcium sulfate dihydrate can be equipped with a combustion furnace that directly produces flue gas. The gas fuel can be natural gas, oil gas, etc.
If the material being processed cannot be contaminated, hot air is used as the heat carrier. The hot air is heated by an air preheater, and the heating medium can be a steam heater, an electric heater, or heat the air through a flue gas preheater. It can also be heated using other industrial waste heat gases, or indirectly heated, where the heat is transferred from the metal wall to the material being dried, such as in an externally heated drum dryer.
If the dried object is not to be contaminated and must not be diluted by air, heat should be transferred through the drum wall. In this case, the drum is loaded into the brick chamber, with flue gas passing through the exterior. It can also be equipped with a central pipeline or a series of pipes inside the drum, or surface heat exchangers such as jacketed tubes, utilizing heat transfer through metal walls. The heat carrier can be flue gas, steam, or electrically heated. In the drying process, only clean gas is used to carry away the evaporated moisture.
In summary, the choice of heat carrier should be based on material requirements and local natural advantages; otherwise, it may affect production efficiency and economic benefits.