Working principle of disc dryer

The wet material is continuously added to the first layer of drying disc on the upper part of the dryer by the feeder, and the rake arm with rake blades rotates to continuously flip the material. The material flows along an exponential spiral over the surface of the drying disc, and the material on the small drying disc is transferred to the outer edge, where it falls onto the outer edge of the large drying disc below. The material moves inward on the large drying disc and falls into the next layer of small drying disc from the middle feeding port. The drying plates of different sizes are arranged alternately up and down, allowing the material to flow continuously through the entire dryer. A hollow drying tray is filled with heating medium, which includes saturated steam, hot water, and thermal oil. The heating medium enters from one end of the drying tray and exits from the other end. The dried material falls from the second layer of the drying tray to the bottom of the shell, and is then transferred by the rake blades to the discharge port for discharge. Moisture escapes from the material and is discharged through the dehumidification port located on the top cover. The moisture in the vacuum disc dryer is extracted through the vacuum pump port located on the top cover. Dry materials discharged from the bottom layer can be directly packaged. By adding auxiliary equipment such as fin heaters, solvent recovery condensers, bag filters, dry material mixing mechanisms, and induced draft fans, the production capacity of drying can be improved. Drying paste like and heat sensitive materials can facilitate solvent recovery and enable pyrolysis and reaction operations.

  The main application areas of disc dryer

Drying, pyrolysis, calcination, cooling, reaction, sublimation
（1） Organic chemical products
Organic chemical raw materials and intermediates such as polyvinyl chloride resin, polytetrafluoroethylene resin, fumaric acid, anthraquinone, nitroanthraquinone, para aminophenol, melamine, cyanuric acid, para aminobenzenesulfonic acid, antioxidant 168, chromophenol As, stearate, aniline, nitroaniline, dipentaerythritol, chlorinated paraffin, calcium formate, triethylenediamine, sodium benzenesulfonate, isophthalic acid, sodium dimethyl pentasulfonate, thiourea, oil soluble aniline black dye, acid black dye, etc.
（2） Inorganic chemical products
Light calcium carbonate, active calcium carbonate, nano scale ultrafine calcium carbonate, magnesium carbonate, aluminum hydroxide, white gray black, strontium carbonate, barium carbonate, potassium carbonate, lithopone, insurance powder, barium sulfate, potassium sulfate, microsphere catalyst, magnesium hydroxide, copper sulfate, nickel sulfate, nickel amine, sodium molybdate, sodium chloride, cryolite, iron oxide red, lithium hydroxide, nickel hydroxide, zirconium hydroxide, calcium phosphate, sulfur, etc.

（3） Medicine and food
Amphotericin, Deng salt, L-phenylglycine and intermediates, cefotaxime, ceftriaxone, metamizole, cimetidine, vitamin B12, vitamin C, medicinal salts, medicinal aluminum hydroxide, medicinal magnesium silicate, caffeine, tea, flower extracts, ginkgo leaves, chocolate powder, starch, corn germ and other raw materials and pharmaceutical intermediates.
（4） Feed and fertilizer
Potassium carbonate, bio potassium fertilizer, protein feed, feed grade streptomycin, mycelium, bran, distiller's grains, grains, seeds, herbicides, cellulose, feed grade calcium hydrogen phosphate, etc.
  

  Characteristics of using disc dryer

（1） Easy regulation and strong applicability
1. Adjusting the thickness of the material layer, spindle speed, number of rake arms, rake blade type and size can achieve optimal drying process.
2. Each layer of the drying tray can be separately filled with hot or cold medium to heat or cool the material, and the temperature control of the material is accurate and easy.
3. The residence time of materials can be adjusted.
4. The material flow is single, with no backmixing phenomenon, uniform drying, stable quality, and no need for mixing.

（2） Simple and easy to operate
1. The operation of driving and parking the dryer is very simple.
2. After stopping the feeding, the rake blades that transport the material can quickly empty the material inside the dryer.
3. Through special large inspection doors and mirrors, the equipment can be carefully cleaned and observed inside.
（3） Low energy consumption
1. The material layer is very thin, the spindle speed is low, and the material conveying system requires less power and consumes less electricity.
2. Drying with conductive heat results in high thermal efficiency and low energy consumption.
（4） Good operating environment, recyclable solvents, and dust emissions meet requirements
1. Atmospheric pressure type: Due to the low air flow rate and low humidity distribution inside the equipment, it is difficult for dust to float to the top of the equipment. Therefore, the exhaust gas discharged from the top moisture outlet contains almost no dust.
2. Sealed type: equipped with a solvent recovery device, which can easily recover organic solvents from wet gas. The solvent recovery device is simple and has a high recovery rate. For flammable, explosive, toxic, and easily oxidizable materials, nitrogen can be used as a carrier gas for closed-loop circulation to ensure safe operation. Specially suitable for drying flammable, explosive, and toxic materials.
3. Vacuum type: A disc dryer operated in a vacuum state, particularly suitable for drying heat sensitive materials.
（5） Easy installation and small footprint
1. The dryer is shipped as a whole and only needs to be lifted into place for easy installation and positioning.
2. Due to the layered arrangement and vertical installation of the drying tray, even if the drying area is large, the footprint is also very small.

  Technical characteristics of disc dryer

（1） Drying dish
1. Design pressure: generally 0.4MPa, up to 1.6MPa.
2. High operating pressure: generally ≤ 0.4 MPa, up to 1.6 MPa.
3. Heating medium: steam, hot water, thermal oil. When the temperature of the drying disc is ≤ 100 ℃, hot water is used for heating. When the temperature is between 100 ℃ and 150 ℃, saturated steam or superheated steam with a pressure of ≤ 0.4 MPa is used for heating. When the temperature is between 150 ℃ and 320 ℃, thermal oil is used for heating. When the temperature is above 320 ℃, heating methods such as electricity, thermal oil, and molten salt can be used.
（2） Material conveying system
1. Spindle speed: 1-10 revolutions per minute, electromagnetic or variable frequency stepless speed regulation.
2. Rake arm: There are 2-8 rake arms fixed on the main shaft on each layer of the drying disc.
3. Rake blade: Twisted onto the rake arm, it can float up and down with the disc surface to maintain contact, and has various types.
4. Rolling: For materials that are prone to clumping and need to be crushed, adding rolling at appropriate positions can enhance heat transfer and drying processes.
（3） Shell
There are three types: atmospheric pressure, sealed, and vacuum
1. Atmospheric pressure type: Original cylinder or octagonal prism, with two types of structures: integral and split. The main pipeline for the inlet and outlet of the heating medium can be located inside or outside the shell.
2. Sealed type: A cylindrical shell that can withstand an internal pressure of 5KPa. The main inlet and outlet pipes for the heating medium can be located inside or outside the shell.
3. Vacuum type: cylindrical shell, designed for an external pressure of 0.1MPa, with the main inlet and outlet pipelines of the heating medium inside the shell.

  Technical specifications for disc dryer