Types of FBD
Mainly there are two types of Fluidized Bed Dryer
- Horizontal Fluidized Bed Dryer
- Vertical Fluidized Bed Dryer
Horizontal Fluidized Bed Dryer
This type of Fluidized-Bed Dryer is also called the Continuous type of Fluidized-Bed Dryer because in this dryer the drying process is continuously in progress.
This dryer consists of a moving bed which is loaded by the trays containing the material to be dried. The base of the trays is perforated and hot air can easily cross them. These trays pass through different chambers within a planet. Each chamber has an air inlet in the base and an air outlet at the top. All the outlets open in the pipe which exhausts the air. Each chamber gets the air supply but in each chamber, the temperature of the entering hot air gradually rises. The first chamber is for the simple air, the second is for the slight hot air, the third is for more hot air, and the last one is for the hottest air. Firstly, the air passes through the perforation and the material is pushed up behaving like a fluid. Then in the next chamber, the air is vaporized and filtered but the granular air is left behind as dried at last.
Vertical Fluidized Bed Dryer
This type of Fluidized-Bed Dryer is also called as Batch Type Of
Fluidized Bed Dryer. As the name indicate here a complete batch of product is dried.
In this dryer, the air stream is introduced by a fan which is present in the upper part of the apparatus. This air is heated in an air heater and flows upward through the material present in the drying chambers. It is fitted with a wire mesh support at the bottom. A bag collector fitter is provided at the top of the chamber so all the material is lifted and only air passes through it.
Other segregation of Fluid Bed Dryers
Conventional Fluidized Bed Dryers
- Batch fluidized bed dryers
- Continuous fluidized dryers
- Semi-continuous fluidized bed dryers
- Well-mixed, continuous fluidized dryers
- Plug flow fluidized bed dryer
Modified Fluidized Bed Dryers
- Hybrid fluidized bed dryers
- Pulsating fluidized bed dryers
- Fluidized bed dryer with immersed heat exchange
- Mechanically assisted fluidized bed dryer
- Vibrated fluidized bed dryer
- Agitated fluidized bed dryer/swirl fluidizers
- Fluidized bed dryers of inert particles
- Spouted bed dryer
- Recirculating fluidized bed dryer
- Jetting fluidized bed dryer
- Superheated steam fluidized bed dryer
- Fluidized bed freeze dryer
- Heat pump fluidized dryers
Static Bed Dryer
Fluidized Bed Dryer Applications in Different Industries
Pharmaceutical and Nutraceutical Industry
A fluid Bed Dryer is one of the key and soul parts of the pharmaceutical industry because different dosages of tablets, powders, and granules are processed by this equipment. When tablets are processed they withstand environmental conditions and can be transported without melting. In a pharmaceutical in a slight coating, it is used.
Chemical and Dyes Industry
In the chemical industry, this equipment is used for drying different chemical particles. Some particles should be available to the final consumer in a dry state, so this machine helps in drying them to the required conditions. It is also used for the conversion of liquid into molds that are dust-free.
Food Preparation Industry
Food is the most consumable item in the world. So the safety of food is guaranteed by this equipment. With this equipment food item’s shelf life can be increased. For longer shelf life we have to make our product dry by this machine. Some important steps of food preparation using this machine include drying, heating, sterilization, roasting, and eventual cooling. In food industries, the FBD is used as a coloring agent for different food products.
Fertilizer and Pesticide Industries
For the production of large-scale inorganic fertilizer such as magnesium, potassium, calcium, nitrate, etc. we use FBD. The function of FBD is the same in fertilizer industries as it is in chemical industries.
Dairy Industries
The fluidized bed dryer is used in drying milk for instant milk powder. In this way crystallization of powdered milk is also possible. Different dairy products are processed by this machine.
Other Application Industries
- Sugar Industries
- Sand Industries
- Salt Industries
- Detergent powder Industries
- Metallurgical Industries
Safety Features for Fluidized Bed Dryer
Emergency STOP
This is an emergency stopping system or button which stops all the machinery movement at once. This should be present in an easily accessible and easily approachable position, which should be pressed in an emergency to stop the machinery.
Alarm and Warning
The system should inform the operator in case of any emergency and should shut off the whole system automatically in critical condition. The operator should give a quick response to the Warning alarm and should reset it after the second operation.
Explosion Relief
There should be a specific built-in system for explosion relief. All the areas and surroundings should be explosion-free. All parts and drives should be covered and protected. The noise should be at a minimum. The electric wires should be labeled and each should be on a specific color.
Advantages of Fluidized Bed Dryer
- In a fluidized bed dryer, the batch of the tablet can be dried within
- 20-30 minutes because of its efficient heating
- The temperature of the fluidized bed dryer is easily controllable
- The Same Temperature Continuously remains
- The fluidized bed dryer manufactures free-flowing products
- The handling of this planet is very simple and labor cost is also reduced
- The horizontal fluidized bed dryer is unlimited for the operation because it can work continuously
- There is no lumps formation
- Material is dried from particle to particle
- Temperature control is good
- In Fluidized Bed Dryer there is a high mass and high heat transfer phenomenon between the particles and gas
Disadvantages of Fluidized Bed Dryer
- The particle usually breaks down in the Fluid Bed Dryer.
- In Fluidized Bed Dryer only a limited range of material is dried.
- In a Fluidized Bed Dryer, the size of particles is relatively large.
- Difficult in the processing of needle or platelet shape particles.
- Due to the collision of a particle with pipe and vessel walls erosion occurs.
- It is difficult to predict the bubbling bed if fine particles and are less efficient.
- It is difficult to predict a non-uniform flow pattern.
- Due to the complex structure and other complexity,
- it is difficult to do fluidization process on the low scale rather than industrial scale.
Common Problems in Fluidized Bed Dryer and its Solutions
If Material is degraded?
if the material is degraded in FBD the possible cause may be very high temperature.
So the solution is slow down the temperature and distributes the whole particle.
If Drying Time is High?
If the material is taking too much time to dry, so the possible cause is material is containing high moisture content.
So the solution, it is preferred to do twice drying process.
Reduced Particle Size?
If the particle size is reduced, then the possible cause is high residence time.
So the solution for this problem is to reduce residence time.
High Moisture level in dry solids?
If the material is containing a high moisture level in the dry solid-state then the cause may be internal diffusion of the particle.
So the solution for this problem is to reduce residence time.
Material is not fluidizing?
If the material is not fluidizing, then the possible cause may be that the powder has developed an electrostatic charge.
The solution for this problem is to use efficient electrical earthling of the drying chamber.
Surface shrinkage?
If the surface is shrunk. Then the possible cause may be high temperature.
The solution for this problem is to optimize the temperature.