Fluidized Bed Dryer Principle:
Fluidized Bed Dryer is used in many applications like: drying of powders, mixing of powders, agglomeration, chemical, pharmaceutical, dyestuff, foodstuff, dairy and various other process industries.Now we discussed about the Principles of Fluidized Bed Dryer. Usually with the spray dryers and granulation systems, we use Fluid bed dryers for effective drying, mixing, granulation, finishing and cooling of powdered substances.
Principles of Fluidized Bed Dryer:
At a certain velocity through a bed of material, when a stream of air is passed upwards the bed will first expand, then it is suspended and distressed by the air stream to form a fluidised bed. The development of many small bubble scan cause to you to see the appearance of a boiling liquid. This process is also called as "bubbling fluidisation".Large bubbles and plugs of material are formed when the velocities of air are going higher. The result of this function has created a more violent type of fluidisation which is known as slugging or sprouting. In the smooth bubbling we can prefer those materials which are uniform in size, may be more amenable to sprouting fluidisation. The Prime operating air velocity for bubbling fluidization is lying above the minimum fluidising velocity, but it lies below the swiftness of entertainment of the material.
Because of the heated air stream, if a bed of the wet material is fluidized, so in the laboratory batch dryer, the situations are ideal for drying. Due to the turbulence of the bed, the very efficient contact between air and solid particles resulting higher heat transfer rates causing rapid disappearance of moisture which is accepted by the exit air. Most of the heat input is used in vaporizing the moisture. It causes the high thermal efficiency in this process. When the exposure to air is near completion the exit air is rises in temperature.
The conditions of temperature and humidity content are uniform throughout the bed, in the result of very good mixing of particles in the fluidised state. By using this process, you can obtain a uniform product. The fluidisation causes very little abrasion and the temperature can be set to ensure no loss of properties for heat sensitive materials, so the product, which is formed through this way cannot be affected.
In the industrial fluidised bed dryers, both batch and continuous types at same Principal is used. Because of this the JMC laboratory fluid bed dryer is used to assess different kinds of materials for large scale fluid used dried.
Advantages of Fluidized Bed Dryer:
- In each hood there is a large service door.
- For cleaning the fin plates can be adjusted vertically by using gear motor.
- Service doors are equipped with gas spring elements for easy access.
- The bottom plate of the trough is accomplished with a special behavior in order to achieve a uniform and consistent drying result.
- The modules can be pre-wired and send it with the electrical fittings and local disconnect box.
- The dryer is equipped with two large cloistered tops of stainless steel.
- The fine adjustment of the process air velocity can be set up with the outside by special damper units.
- For cleaning work you can adjust flow straightener upward and downward.
- The process air distribution chamber is completely insulated and all inner parts are made with stainless steel.
- The design of the hood prevents over-dried tobacco accumulation along the side walls of the process areas and guarantees a perfect average of tobacco moisture.
- The vibrating trough is made of high-grade stainless steel.
- Under the roof fin, plates are situated in a specific order to achieve a uniform downstream air flow.
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