1、 Overview of horizontal disc dryer
The horizontal disc dryer consists of a circular shell with a jacket, an upper cover, a hollow shaft with blades, end caps at both ends, a rotating joint with a medium, a metal hose, and a transmission mechanism including a sprocket.
The core of the horizontal disc dryer is a hollow shaft and hollow stirring disc blades welded to the shaft. A hollow disk with a circular shape that can be filled with a heating medium. In addition to its stirring function, it is also the heat transfer element of the equipment. When the material comes into contact with the disc, as the disc blades rotate, the material quickly slides away from the disc, constantly updating the heat transfer surface and enhancing heat transfer. There are push plates around the disc to scrape the material and prevent blind spots.
The arrangement of the disc and the dimensions of each part have certain requirements, and in addition to the disc, auxiliary mechanisms are also provided in the feeding area, drying area, and discharging area to ensure stable operation and uniform drying of the whole machine. In addition, the duration of stay can also be adjusted.
The heat transfer surface of the disc dryer consists of several parts such as blades, stirring shaft, and wall surface, and the heat transfer area of the blades accounts for a large part, so the equipment structure is compact and the heat transfer area per unit volume is large. In addition, stirring and mixing cause the material to vigorously flip, thereby achieving a high heat transfer coefficient, resulting in a small footprint and space, saving on factory construction costs. The drying process requires less gas and has a low flow rate, resulting in less dust being carried away by the gas. Therefore, the recovery of gas and dust after drying is convenient, and the recovery equipment has a small volume, which can save equipment investment. For the drying process that requires solvent recovery, the solvent concentration can be greatly increased. Due to the special structure of the disc, the material undergoes alternating compression and relaxation during the drying process, which enhances the drying process. The filling rate of materials in the drying room is very high, which can reach 80% -90%. The residence time of materials can be adjusted by adjusting parameters such as feeding speed, stirring shaft speed, and material filling degree, from a few minutes to several hours. In addition, the material in the dryer moves from the feeding port to the discharging port in a piston motion, with a narrow residence time distribution, resulting in a uniform moisture content of the product. The disc has a certain axial angle on the mixing shaft, allowing for continuous drying of the material.
2、 Working principle of horizontal disc dryer
The horizontal disc dryer is a type of horizontal stirring continuous drying equipment that mainly relies on heat conduction. Due to the circular shape of the stirring blades, it is called a disc dryer.
The material is fed into the dryer through the feeding port, and the working medium flows between the shell jacket (coil type) and the hollow shaft. Heat is transmitted through the jacket, hollow shaft, and hollow disk welded on the shaft. The material is indirectly heated and dried, and the generated water vapor accumulates at the top of the dryer and is carried out of the dryer by supplementary air. The hollow disc is completely perpendicular to the shaft and does not cut the material. The material is pushed and stirred by the edge of the disc/agitator, continuously updating the drying surface to achieve the purpose of drying.
3、 Application of horizontal disc dryer:
Horizontal disc dryer is a large-scale indirect drying equipment that has been widely used in sludge (municipal, chemical, papermaking, electroplating, printing and dyeing, etc.)
4、 Characteristics of horizontal disc dryer equipment
1. The surface of the heat transfer disk is smooth, not easy to scale, not easy to wear, and has good heat transfer performance.
2. The blades inside the dryer are buried in the material, and the heat transfer area can be fully utilized.
3. The rotating disc is equipped with a scraper, which can clean the material on the surface of the disc and adjust the residence time of the material in the dryer
4. Closed operation of drying engineering is suitable for situations where wet gases are harmful and have odors. Low environmental pollution, minimal air carrying capacity, and minimal dust and material entrainment.
5. The equipment runs smoothly and is easy to operate and maintain; It can be operated continuously or intermittently.
6. The heat transfer medium can be steam, thermal oil, and hot water
7. Low energy consumption of the dryer: Due to indirect heating, the mixing is uniform, the thermal efficiency is high, the material is not contaminated, the drying effect is good, and there is no large amount of air carrying away heat. The outer wall of the dryer is also equipped with an insulation layer, so the heat loss is very small.
8. Low cost of dryer system: With a huge heat transfer surface per unit effective volume, the processing time is shortened, the equipment size is reduced, and the footprint is reduced.
9. Wide range of material processing: Using different heat media, it can handle both thermosensitive materials and materials that require high-temperature treatment. The disc shaft has low rotation speed and does not damage the shape and properties of the product.
10. Stable operation: Due to the special compression expansion stirring effect of the disc, the material particles are fully in contact with the heat transfer area. In the axial range, the temperature, humidity, mixing temperature, and gradient of the material are very small, thereby ensuring the stability of the process.
11. Can be designed for production lines and used in conjunction with other upstream and downstream processes
