Parts of FBD
In the Fluidized bed dryer construction, three systems are mainly functions.
- Inlet Air Handling Unit
- Main Stainless Steel Tower
- Exhaust System
- Control Panel
Inlet Air Handling Unit
The air handling unit is a rectangular container, from one side fresh air enter and the other end is linked to a fluid bed dryer. It has further components.
The primary filter is also known as the G4 class filter. G4 class filter removes those particles, which we can see with our naked eye. e.g. pollen grain of flower, the power of filtration of a primary filter is up to 10 µm particles.
It is the second filter after the G4 filter. It removes very fine dust particles ranging in size as small as 1µm.
There are two kinds of Dehumidifiers.
- Condenser Coil Dehumidifier.
The condenser coil dehumidifier is doing the function of cooling the surface.
- Wheel Type Dehumidifier Unit.
Wheel type dehumidifier is also named as Desiccant dehumidification Wheel. It consists of a wheel, and that wheel is made up of corrugated material. The wheel has desiccant material, which attracts water from the air. A desiccant wheel is used mainly in those cases when the air is of low humidity. Mostly silica gel is used as a desiccant material.
The Air Handling Unit contains two dehumidifiers. The condenser coil is positioned before the wheel dehumidifier unit.
Dehumidifier has further parts
It passes air from the surrounding but inside the air heating unit and passes it to the filters and into the heating chamber.
- Heating Pipes
As the process of filtration and dehumidifying is completed in the next step the heating of air starts. The air which is coming from the surrounding is usually cool, so this cool air absorbs heat from Heating Pipes.
The pipe may be heated in two ways either steam or electricity. Air Heating Unit comes with electric heating coils.
- HEPA Filter
As the air leaves AHU it undergoes the final filtration process. In this, we use a highly efficient HEPA filter, which can remove very small particles ranging in size as small as 0.3µm in diameter.
The mechanical filters contain fibers arranged randomly forming a dense mat it removes spores, pigments, tobacco smoke and bacteria, etc etc.
Main Stainless Steel Tower
It contains the following main parts.
The base part of the stainless steel tower is also called as Bowl/ Bottom Chamber. It is connected to the AHU through a stainless steel tube ferrying the clean, hot, and dry air. A butterfly valve is present on the air inlet tube if this valve is closed so the air intake is stopped.
Inlet air plenum is present in the bottom part. Inlet air plenum helps in the transfer of air up in the main tower. The bottom chamber and the product chamber are interlocked before the production starts.
As the name indicate this container contains wet materials that need drying. Those wet granules are produced by a high shear mixer. The product container moves with the help of a moveable trolley. Sometimes product container is removed from the fluidized bed dryer and moved to other process equipment such as Lifting Column. Another important feature of the product container is the bottom mesh or distributor plate. It is held in place using S.S clamps.
It is a metal screen with some perforation. its function is to stop airflow coming from the bottom chamber, so by this function, it distributes the air around the product container. The mesh also holds the product.
Some other important functions of the product are
- viewing glass port which helps the operator to do visual feedback.
- sampling port (it provides an easy collection of samples from the product container.
- product temperature sensor (it helps in analyzing product temperature.
It is located on the upper side of the product container. The product container and process chamber are designed to make it airtight with an inflatable gasket. It is the main area where fluidization takes place. Air is attracted from the bottom bowl and product chamber to the main tower.
Expansion Chamber and Filter Housing Chamber
The expansion chamber forms the center part of the tower. It is mixed in the filter housing chamber in which the double structure filter bag is held. The filter bag is a structure just like a sac suspended over the process chamber. As the air moves upward so it may carry some small particles with it. These small particles are known as fines. The filter bag controls these fines not to move outside from the system.
Two cylindrical pipes come out from the expansion of the fluidized bed dryer from each part of a filter bag. These two pipes are made in a vent that is connected to the blower. These are fixed by the actuators with the dampers. The actuator is a device that moves the damper so it is allowing the opening and closure of the vents. For the operation first, it must receive an electrical signal from the control system. There is a second filter unit present in Some fluidized bed dryers. The function of this filtering unit is the capture of fines that comes out from the filter bag system, so it provides a high filtering unit. In this way, the environment air is protected from exhaust particles.
Draught Fan/ Blower
In a fluid bed dryer, a centrifugal type blower is used. The main part of its being
- Drive mechanism
- Inlet and outlet duct
When it works, the impellers rotate so it compels the air molecule to rotate. So the centrifugal force on the air molecule is impacted by the impeller causing the air molecule to move radially out.
Externally, air receives positive pressure and kinetic energy and it is expelled from the system… Inside the blower, the displacement of air makes negative pressure. So more air enters the blower. Centrifugal pumps are most important for drawing air. The fluidized Bed Dryer industrial crystal has a steel construction that increases anti-vibration and calms it.
The inlet temperature can be controlled from the control panel by the operator. By the control bag, we set the filter bag shaking time. On and Off of the blower motor is done by the control panel.
lift and lowering of the product chamber is done by the control panel.
The control panel read the exhaust temperature. Apart from this control panel perform many important functions.
What Is Fluid Bed Dryer?
It is a unit operation in which liquid is separated from solid in a non-mechanical way. This process is completed by supplying heat and evaporation of liquid.
Main Purposes of Drying
- The drying process increases the shelf life of the product.
- The drying process helps in the preservation of the material
- Drying improves or sustains good properties of the material such as flowability, and compressibility.
- The drying process helps material in easy and more suitable for handling.
- The drying process helps in the reduction of the transportation cost of the material.
What types of feed are used for Drying Process?
- Wet Solids
In the Pharmaceutical industry, chemical industry, and food industry the drying process plays a vital role.
In the Fluidization process, the static solid-like state granular material is converted to a dynamic fluid-like state. Fluidization is a suspension of the solid particle in a stream of fast-moving air.
It is referring to a layer of suspended solid particles.
It is a piece of equipment where wet particles are converted into solid dried particles.
Definition of Fluidized Bed Dryer
A Fluidized Bed Dryer is a piece of industrial equipment that is extensively used for reducing moisture content in different products. It is mostly used in the pharmaceutical industry for reducing moisture content in the powders or granules for the manufacture of solid dosage drugs, in other industries it is used in plastics, fertilizer, and foodstuff industries.