Spin Flash Dryer

Overview

  The spin flash dryer is an innovative product independently developed and designed by our company through absorbing and boldly adopting advanced foreign technology and combining it with the actual conditions of domestic drying. Hot air enters the main tower of the spin flash dryer tangentially from the air inlet at the bottom of the main machine, forming a spiral upward high-speed rotating airflow inside the main tower. At the same time, the size of the annular gap at the bottom is adjusted according to different material properties to maintain the air velocity at an appropriate level. The material is fed directly into the spin flash drying tower through a screw feeder. Under the impact and entrainment of the high-speed airflow, it quickly disperses and rotates at high speed with the airflow. For relatively large and wet particle agglomerates, the high-speed airflow is insufficient to break them apart and make them rotate at high speed, so they gradually fall under gravity. When they reach the bottom of the main machine, they are forcibly crushed and micronized by the crushing device installed at the bottom, and then rotate upward together with the high-speed airflow to complete the drying process. In order to achieve extremely low final moisture content while preventing fluctuations in initial moisture content from affecting product quality, multiple layers of swirl plates are installed in the drying tower to form a relatively stable fluidized bed. At the same time, the swirl plates also ensure the necessary residence time for drying and provide a classification function, thereby achieving integrated high-efficiency drying and particle size classification.

Working Principle

  The working principle of the spin flash dryer is based on "flash" rapid drying. The core process is as follows: Hot air enters the drying chamber tangentially from the bottom and forms a powerful rotating airflow field under the action of a high-speed agitator. Meanwhile, paste-like or filter cake-like materials are fed into the bottom of the drying chamber by a screw feeder, where they are rapidly dispersed and crushed under the intense impact, friction, and shear action of the high-speed rotating stirring blades. These micronized materials come into full contact with the rotating hot air. The huge heat exchange area causes moisture to evaporate violently within an extremely short time (usually 1 to 5 seconds). The dried material rises with the hot airflow. When passing through the classification ring at the top, large particles are intercepted and fall back for further crushing and drying, while small particles that meet the fineness requirements are discharged with the airflow and recovered by collection devices such as a cyclone separator and bag filter.

Features

  Dual-duct tangential air inlet is adopted, avoiding the velocity non-uniformity of the rotating field in the radial flow field.
  2. Final moisture content and fineness are effectively controlled through the coordinated control of swirl plates and inlet air velocity.
  3. The rotating blades feature a unique arrangement, with characteristics such as low wear, wide contact area, and high cutting force.
  4. It is adept at handling heat-sensitive materials. The bottom of the main machine is a high-temperature zone, where the air velocity is high and a cooling water protection device is provided, avoiding the possibility of material coking and discoloration.
  5. The system has low resistance, high thermal efficiency, a good operating environment, and low labor intensity.
  6. The main machine adopts a new sealing structure, extending the service life of the main machine bearings, and the bearing housing is equipped with a water jacket circulating cooling device.

Applications

  Inorganic substances: borax, calcium carbonate, hydroxides, copper sulfate, iron oxide, barium carbonate, antimony trioxide, various metal hydroxides, various inorganic salts, synthetic cryolite, etc.
  Ceramics: kaolin, silicon dioxide, clay, etc.
  Food: soy protein, gelatinized starch, distiller's grains, wheat sugar, wheat starch, etc.
  Organic substances: atrazine (pesticide insecticide), cadmium laurate, benzoic acid, benzoic acid, fungicide, sodium oxalate, cellulose acetate, etc.
  Dyes: anthraquinone, black iron oxide, indigo pigment, butyric acid, titanium hydroxide, zinc sulfide, various azo dye intermediates.

Flow Diagram