Fluid Bed Processors: The Ultimate FAQ Guide

What is the Fluid Bed Process?

The fluid bed process involves the fluidization of different mixture components to improve compressibility and flowability using a fluid bed machine.

Fluidization process

What is Fluid Bed Granulation?

Fluid bed granulation is the process of forming granules or grains from solid or powdery substances using a fluid bed machine.

It is the agglomeration of finer particles into larger ones by adding binder liquids to the particles to form aggregate granules.

Apart from improving the material properties such as compressibility and flowability, granulation also avoids the segregation of the mixture components.

Fluid bed granulator

What is Fluid Bed Equipment?

Fluid bed equipment is the set of machines you can use to reduce the moisture content of pharmaceutical granules or powder.

Apart from that, you can use the fluid bed equipment in the granulation or coating processes of different particles.

This equipment depends on the fluidization principle of the particles to make the drying and granulation process a success.

What are Fluid Bed Processors Used for?

You can use a fluid processor for the following purposes:

• Mixing of particles
• Coating of particulate material
• The layering of particles such as drugs in the pharmaceutical industry
• Transformation of powder particles into granules
• Eliminating moisture from wet particles or granules
• Improving flowability and dispersibility of particles
• Increase the stability of the granules by making them moisture resistant.
• Pelletizing and Spheronizing of particles.

Which Industries Use Fluid Bed Processor?

• The pharmaceutical industry in the making of drugs in the form of tablets
• Food processing industry to improve flowability and dispersibility of food products
• Chemical industries to improve the storage or general handling time.
• The cosmetic industry for making different beauty products
• Petrochemical industry

What is Fluidization Technology?

Fluidization technology is the technical process where granular materials convert from static solid-like states to dynamic fluid-like states.

The process occurs when gasses or liquids pass up through granular materials at high pressure.

Fluidization process

When was Fluidization Technology Invented?

Fluidization technology was invented in the nineteenth century around 1922 by a German scientist by the name Fritz Winkler.

He came up with the first industrial application of the fluidization technology for a gasification process of coal.

SaintyCo Manufactures Which Fluid Bed Processors?

SaintyCo manufactures different types of fluid bed processors, such as:

• Mini DPL Lab Fluid Bed Granulator and Coater
• Mini FBG Lab Fluid Bed Dryer
• FBG Fluid Bed Granulator
• FG Fluid Bed Dryer
• DPL Multifunction Fluid Bed Granulator and Coater

What is a Fluidized Bed in Pharmaceutical Material Processing?

A fluidized bed refers to particles or material suspended by a stream of air.

Through fluidized bed, you can granulate, coat or dry particles.

Fluidized bed

What Fluidized Bed Types are there?

You can easily identify different types of fluidized bed types by their flow behavior.

The main types of fluidized bed include:

· Bubbling or Stationery Fluidized Bed

The fluid flows at low velocity to fluidize stationery solid particles.

· Circulating Fluidized Beds (CFB)

It is capable of fluidizing more particles at high pressure due to the rough and circulating bed.

It also has an external loopback that is capable of recirculating entrained particles back to the bed of the reactor.

The particle size also determines whether the classification of the particles using a cyclone separator.

· Vibratory Fluidized Beds

It is similar to a stationary fluidized bed except for the fact that it vibrates to add additional excitement to the particles.

The vibration of the machine increases the entrainment of the fluidized bed.

· Flash or Transport Reactor

The machine operates at velocities that are higher than the operating velocity of circulating fluidized beds.

The particles are fluidized at a velocity that approaches the velocity of the gas.

Slip velocity between solid and gas reduces significantly at the cost of minimal distribution of heat.

· Annular Fluidized Bed (AFB)

It consists of a large nozzle right at the center of a bubble bed that introduces gas at a very high velocity.

It can achieve a higher speed of mixing above the surrounding bed in comparison to that of the external loop.

· Mechanically Fluidized Reactor (MFR)

It has a mechanical stirrer that mobilizes particles to achieve properties similar to properties of a properly mixed fluidized bed.

This type of fluidized bed does not depend on a fluidized gas to perform its functions.

· Narrow Fluidized Beds (NFB)

The ratio between the grain diameter and the tube is less than or equal to 10.

It also has a strong confinement effect that differentiates its dynamics from the dynamics of other types of fluidized beds.

It is because it creates a strong confinement effect.

What’s more, it has granular plugs with more solid concentration alternating with areas of lower solid concentration.

What is Minimum Fluidization?

FigMinimum fluidization velocity – Photo courtesy: Science direct

Basically, minimum fluidization is fluidization at minimum velocity.

It is the velocity at which you can fully fluidize a bed of particle depending on your fluidization requirements.

Minimum fluidization velocity is the superficial speed of gas where the drag force of the gas and particle weight is equal.

Minimum fluidization is one of the major requirements that you have to include during the designing process of fluidized beds.

Fluidized beds have different minimum fluidization velocities depending on the applications.

Are Fluid Bed Processors Used in Wet Granulation?

Fluid bed granulator

Yes, fluidized bed processors are used in wet granulation.

You will need a fluid bed granulation machine that can perform wet granulation by adding a binder to the particles.

The materials that you want to granulate suspends within the fluid bed when you apply air at high velocity.

It sets up a fluidized bed of materials after which you will spray the binder on to the powder.

The result is binding of particles against each other hence the formation of aggregated granules.

As soon as the granulation process is complete, the granules go through a drying process to eliminate excess moisture.

What are the Benefits of Fluid Bed Processing?

You will experience the following benefits during the period of fluid bed processing:

• Fluid bed processing is a fast and homogenous process that guarantees great results through all the processes.
• The fluid bed processors are reliable machines that you can for different materials, including heat-sensitive materials.
• The fluid bed processors also ensure efficiency in all the processes.
• It is easy to handle the fluid bed processors as you will require very few people to assist you in the process.
• There is a wide range of fluidized bed processors in different sizes available for you to choose from.
• The final products from fluid bed processing are perfect with little to no hot spots.
• The process of fluidization is smooth and continuous with very little downtime; hence, very few requirements for maintenance.
• Fluid bed processing uses machines that are capable of handling different modes of fluid bed processing and granulation.

How Does Fluid Bed Processors Increase Efficiency in Material Processing?

To increase the productivity and efficiency of the fluid bed processors, you need to have a clear understanding of the technology.

Fluid bed processing involves a lot of stages which can also affect the efficiency of the whole process.

You can improve the efficiency of the fluidization process or material processing by understanding the following principles.

· Fluid Bed Dryer often depends on the Fluidization Principle

Almost all fluid bed processors depend on the fluidization principle to perform most of the tasks.

Having a clear grasp of the fluidization process allows you to increase the efficiency of fluid bed processors.

You can adjust a few parameters on the fluid bed processors to obtain optimal fluid bed processing results.

You can detect the efficiency in the fluidization process by looking at the following:

i. An increase in the rates of fluid bed processing such as drying of powders

ii. Improvement in thermal efficiency

iii. Better results on the fluidized process in a smaller area

iv. Precision in control such as controlling the rate of airflow, and temperature among others

v. A decrease in the cost of handling products, thus a higher ROI.

· Ability to Control the Process variables of Fluid Bed Granulation and Drying

To increase the efficiency of the process, you have to have to know how to control the quality of end product.

There are specific aspects that you need to look at as they will influence the quality of the final products.

First, you need to purchase a fluid bed processor which allows you to adjust it according to certain parameters.

Apart from that, you need to understand the transition of different solid states to avoid problems during the process.

The parameters that you need to consider include:

i. Apparatus parameters such as air distribution plate, nozzle height, size and shape of granulator bowl, and positive or negative pressure.

ii. Some variables of the process such as rate of inlet airflow, bedload, inlet humidity and air temperature

You should also include spray angle, nozzle type, droplet size, Atomization airflow and temperature, spraying regime and flow rate.

iii. Product parameters including binder type, binder quantity, binder solvent, and the concentration of the granulating solution

Apart from that, you should consider the granulating solution temperature, powder hydrophobicity and fluidization of the starting material.

You can increase the efficiency of the granulation process by monitoring and adjusting the above parameters accordingly from the control panel.

· Unique Designing that will Guarantees High Efficiency in Processing of Adverse Materials

You have the freedom of choosing the type of fluid bed granulators that suit your requirements.

It implies that you are free to have a pharmaceutical fluid bed processor that will increase the efficiency of the process.

A modern fluid bed processor has simple modifications that can accommodate different processes including drying, powder coating and granulating.

You may choose to have the spray at different points of the fluid bed processor such as:

• Tangential spray
• Top Spray
• Bottom spray.

The direction of flow, especially for the material you intend to process, can either be vertical or horizontal.

This allows you to adopt the parts in any material processing process, thus increasing the efficiency.

Fluid Bed Processors Use Which Types of Sprays?

Fluid bed processors use different types of sprays to perform different functions.

The classification of the types will depend on the position of the spray on the sprays, such as:

Types of sprays

i. Top Spray

You will find the spray nozzle right above the distributor, expansion chamber or product container

You will use top spraying for wet granulation, drying, and coating.

The machine sprays the coating liquid down onto the bed with the fluidized particles.

It is ideal for the coating of larger powders, pellets, and crystals.

ii. Tangential Spray

The position of the spray is adjustable, and you can move it and leave it at different heights.

In many cases, the nozzle is at the side of the expansion chamber or product container.

The working principle involves the spinning of a disk which will generate centrifugal force.

The air generates a lifting force as air passes through the adjustable disk gaps.

A gravitational pull will pull the particles allowing them to fall on the disk.

A combination of the forces leads to proper homogenous mixing, coating and drying of granules with uniform contents.

iii. Bottom Spray

In this case, the spray is at the bottom where particles move up first inside the partitions before coming down.

Repeating the up and down movement of the particles can lead to particle coating.

It is a common process in the pharmaceutical industry for coating and layering of drugs to control release of drugs.

As the hot air passes through the fluidized bed, it will lift the particles in a stream of air.

The stream or suspension of air comes from the bottom spray and is responsible for coating and granulation.

What are the Main Fluid Bed Processor Parts?

The main parts of a fluid bed processor are:

Parts of fluid bed processor

· Fluid bed Nozzle

The nozzles assist in providing the machine with the binder in droplets and control the distribution.

· Air Distribution Plate

It is responsible for the distribution of fluidizing air between the outer and inner partitions.

· Draft Tube or Plenum Chamber

Allows air to enter as it equalizes pressure for a fair distribution of air.

· Cylinder (PG)

It aids the machine is sucking the particles through the partition gaps.

· Filter Bags

It blocks foreign particles from entering the system for increased fluidization of the fluids.

· Expansion Chamber

The expansion chamber assists in the recurrence of the flow of the particles involved.

· Product Container

This is the main area where you will place the powder or products that you would like to fluidize.

· Control Panel

This system comes complete with a variety of control systems for controlling the working parameters of the machine.

· Exhaust Filter

The exhaust filter will block and allow free air into the fluid bed processors system.

· Solution Delivery

This is the main point of delivery where all the solutions you need for the fluidization process goes through.

· Exhaust Blower

The exhaust blower blows off any form of particulate matter that may adhere to the walls of the system.

How Can You Optimize Fluid Bed Processing Technology?

You can optimize fluid bed processing technology by:

· Using Machines Under the Right Working Conditions

You have to service your machine regularly and ensure that it is in proper working condition.

· Using the Right Equipment for the Right Purpose

When choosing the fluid processing equipment, you should go for the equipment that matches your production needs.

· Setting the Right Fluid Bed Processing Parameters

You need to have proper settings that match fluid bed processing requirements.

From the control panel, you can optimize the processes by tuning them to the right specifications.

You must also be able to time the fluid bed processing accordingly.

What is Fluid Bed Drying Technology?

Fluid bed dryer

Fluid drying technology is the process by which a fluid bed dryer eliminates excess moisture from wet granules or particles.

The technology depends on the fluidization process where hot air passes through the spaces between the particles.

The particles suspended in the air due to the equalization of air velocity and gravitational forces below the particles.

You might assume it to be a boiling bed of fluid as the particles suspended above the fluid bed.

The hot air which is in direct contact with material will remove excess moisture as it flows.

The end result is a particle that has the right moisture content according to your drying requirements.

How Do Fluid Bed Dryer Compare to Drying Oven?

Fluid bed driers are equipment that you can use to reduce the moisture content within different particles.

You can use a fluid bed dryer to dry materials in different industries such as:

• Chemical Industry
• Pharmaceutical Industry
• Food industry
• Metallurgical Industry
• Dyes and other process industries

Fluid bed driers depend on the fluidization principle where hot air passes and suspends the particles hence drying them.

Apart from drying, you can use the fluid bed dryer for other purposes such as:

• Mixing of powders to form homogenous mixtures
• Agglomeration or granulation of powder to form drugs and tablets in the pharmaceutical industry

Drying Ovens, on the other hand, are equipment that you can use to remove moisture from certain objects without cooking.

Pharmaceutical oven

Apart from that, you can use a drying oven for other purposes such as:

• Sterilizing of different objects such as laboratory equipment
• Dehydrating of foodstuffs including raisins to extend shelf life.

The drying process does not involve any form of air pressure flowing and suspending the particles.

High temperatures within the drying oven will eliminate the excess moisture from the wet material.

How Does Fluid Bed Dryer Work?

A fluid bed dryer depends on the fluidization principle to eliminate excess moisture from the particles.

First, you will place the particles that you need to dry in the product container.

After that, you will switch on the machine and allow the products to flow straight to the drying bed of the fluid bed dryer.

As that continues, you need to set the drying parameters from the control panel according to your drying specifications.

Power the machine one as soon as the right quantity of the wet powder is in place.

A stream of hot air will pass through the spaces under the bed and on to the particles.

It will blast the particles and suspend them in the air.

As the air velocity of the hot air increases, the upward forces acting on the particles also increase.

As soon as the upward force equals the gravitational pull below the particles, the particle will suspend uniformly in the air.

You can identify the suspension to be in a state of fluidization as it suspends in a boiling bed of liquid.

The particles are in direct contact with the hot air and it removes all the moisture from the particles.

As soon as the particles reach the right moisture content, the blasting stops allowing the dry particles to fall back.

You can now release the dry particles for further processing leaving space for more particles to dry up.

What is the Difference Between Fluid Bed Granulator and FBD?

Fluid bed granulator

Fluid bed granulation is the process of improving material compressibility and flowability to avoid the segregation of mixture components.

It involves a wet granulation process where the machine adds a binder liquid to aggregate and form granules.

Also, it depends on the process of fluidization to aggregate the particles to form granules.

A fluid bed dryer on the hand is a process of drying or eliminating excess moisture from solid particles.

It also depends on the fluidization principle to assist in the elimination of excess moisture.

In this case, the particles lose moisture whereas granulation involves the addition of fluids in the form of binders.

Apart from that, fluid bed drying does not involve the formation of granules which is the sole purpose of the granulation process.

Both processes uses the fluid bed processors to dry and granulate the powder particles.

What is Fluidization Velocity?

Fluidization involves the balance of drag, gravity and buoyant forces.

Fluidization velocity is the speed at which a fluid bed processor fluidizes powder particles.

The fluidization velocity determines the effectiveness of the fluidization process as it increases the surface area of the particles.

Which Fluid Bed Dryer Parameters Affect Quality of End Products?

The fluid bed dryers depend on certain factors that determine the quality of the end products.

The parameters that affect the quality of end products include:

Fluid bed drying system

· Apparatus Parameters such as:

i. Air distribution plate – You should evaluation air distribution plate position since it will determine flow of air in the entire system

ii. The shape of the body if the instrument where the annular base is the best in the formation of products.

iii. Nozzle height when you are considering a granulator and a coater.

The higher it is from reaching the ground, the more time it has to reach the bed surface.

iv. Negative and positive pressure operation

· Process Parameters

You should consider the following inlet air parameters in determining the quality of the end products.

i. Temperature

As the temperature of the inlet air increases, it speeds up the drying process, and vice versa.

Increasing the rate of drying cannot be relied upon as some of the substances are sensitive to high temperatures.

In some products, high temperature leads to blistering while low temperatures lead to the formation of soft spots.

ii. Humidity

You can achieve an effective drying process when inlet air has low humidity.

High humidity within the inlet air will decrease the drying process of the wet particles.

iii. Rate of Airflow

The speed of airflow should be under control to get the best use of the drying air.

When air flows too fast or slow, drying may not be efficient. Therefore set the system for an efficient flow of air.

Product Parameters

These include:

i. The initial moisture content of the materials

The initial moisture content should be as low as possible to reduce the drying time of the particles.

The higher the moisture content, the higher the time it will take to dry the particles.

ii. Batch size

The smaller the batch size, the higher the rate of drying in terms of feasibility.

Fluid Bed Dryers are suitable for which Materials?

Some granules or powders lose or degrade essential properties when you subject them to extreme temperatures or heat.

Such products are, therefore, not suitable for conventional drying using the fluid bed dryers.

Modern fluid bed dryers have sensitive systems that can monitor the essential parameters during the drying process.

You can use the fluid bed dryers on materials such as tablets, granules, fertilizers, powders, and plastics.

The material that you can dry using a fluid bed dryer has to have the following properties:

• It has to have considerable moisture content within the particles
• It has to be of particular uniform sizes and shapes
• It has to be non-volatile thus prompting you to check the flammability of the products.

How many Types of Fluid Bed Dryer are there?

There are different types of fluid bed dryers available in the industry.

The main types of fluid bed drying systems are:

· Batch Type Vertical Fluid Bed Dryers with Granulating Options

This type of fluid bed dryer includes:

i. Reverse Turning Bed Type

When you turn the dispersion plate of the gas to 90 degrees, it will discharge dried material. You can use a motor mechanism to achieve this.

ii. Rotating Discharge Type

Discharge materials after drying through the equipment discharge gate.

The perforated plate acts as the main dispersion plate where pressure pushes the dry materials out of the dryer.

The main characteristics of the batch type vertical fluid bed dryers include:

i. You can control the residence period. With this, you will definitely achieve uniform drying.

ii. It is the most suitable dryer for applications that require the accuracy of the drying period at a decreasing rate.

iii. It is suitable for crystalized or granular materials since small destructions of particles usually occur.

iv. It is automatic thus allowing a continuous flow of processes such as feeding, drying and discharging without human aid.

· Continuous Type Horizontal Vibrating Conveyor Fluid Bed Dryer

The residence time in this particular fluid bed dryer depends on:

i. Length of the drying zone

ii. Amplitude and frequency of vibration

iii. Use of dams with heat transfer units responsible for 60 to 80 % of heat within the equipment.

The main features of this type of fluid bed dryer include:

i. It can dry materials with relatively high moisture content

ii. It can achieve piston flowability by arranging numbers of partition plates at and after the second drying chamber.

iii. It also features perforated plates at the end thus ensuring faster and easy discharge.

iv. It is suitable for crystalline materials because it causes destruction to smaller materials.

v. Heating and cooling of particles often occur in the same chamber

What are the Advantages of Fluidized-Bed Dryer?

You will experience the following advantages when you are using the fluidized bed dryer:

 Fluid bed drying equipment

· Guarantees Homogenous and Fast Drying

It will guarantee homogenous, fast and uniform drying of the particles as long as you understand the mode of operation.

· Suitable for Products that are Sensitive to Heat

You can use it in drying products that are sensitive to heat without causing any damage on the products.

Modern fluid bed dryers have monitoring systems that will detect heat sensitive products and control the drying process parameters.

· Ensure Efficiency in Particle Drying

It increases the efficiency in the drying of materials as it dries all the particles individually.

During the process, the material will be in direct contact with hot air. Consequently, it will increase the efficiency of the drying process.

· Easy to Handle

You can easily handle the fluid bed dryer without involving many laborers in the process.
As long as you have a grasp on the operating principle, you will be able to handle it with minimal problems.

· Lower Cost of Maintenance

It has very few cases of downtime thus reducing the time and cost of maintenance.

Apart from that, it will increase the drying output as you will spend more time operating the machine.

· No Hot Spots on the Final Products

You will not experience hot spots on the final products as the machine is sensitive to different types of materials.

The material is not in direct contact with the drying surface thus reducing the chances of developing hot spots.

· Available in Different Shapes and Sizes

You can choose from the vast types of fluid bed dryers available in different sizes and shapes.

· You can use it in both Batch and Continuous Processing of Materials

It is flexible and can accommodate the continuous and batch drying of the wet granules without doing expensive adjustments.

Other advantages of the fluid bed driers include:

• Reduce dust pollution in the process of drying the granules
• High rates of removing moisture from the wet granules
• Minimal to no migration of soluble substances
• Small in size with very low capacity of production

Are there Limitations of FBD?

Yes, there are limitations that you will experience while using the fluid bed dryer.

Just like any other type of machine, a fluid bed dryer has its own share of disadvantages:

• Possibility of Product Loss

There is a very high possibility of product loss especially when it is in a fluidized state.

You can eliminate this problem by having precise control mechanisms in place.

• High Chances of Electrostatic Build-up

There are very high chances of electrostatic charge generation due to the vigorous movement of the particles.

This often occurs when you are drying organic powders.

You can eliminate this problem by using a fluid bed dryer with electrical earthing.

• Drying Sticky materials is not easy

The fluidization principle requires free particle movement, therefore, adhesive or sticky materials might not move freely.

This makes it quite impossible to use the equipment in such cases.

Other challenges include:

i. High possibility of pressure drop

ii. A decrease in the mechanisms of handling hot air or gas

iii. Product quality is not uniform

iv. Poor fluidization

How Does Tumble Dryer Compare to Fluid Bed Dryer?

Tumble dryers are large baskets that rotate to remove excess moisture from different materials such as Softgel capsules.

Tumble dryer

It has a simple design that facilitates simple and easy drying for the materials.

The machine has elements that produce heat under regulated conditions which assist in draining of excess moisture.

Apart from that, a tumble dryer has tray tunnels without perforations where you will place the material to dry.

It does not involve a suspension of solid material in the air during the drying process.

Tumble dryers may as well be the last drying process of materials but you may proceed to other drying processes.

Fluid bed dryers, on the other end, depending on the fluidization process to assist in the removal of excess moisture.

It blasts velocity of hot air through the particles and in turn suspends them into the air.

All the particles are in touch with the hot air and remove excess moisture from the particles.

The fluid bed dryer is always the last drying option for the particles prompting not need to dry particles further.

What’s more, you need to have solid particles with specific wetness range for an efficient drying process.

Can SaintyCo Customize Fluid Bed Dryer?

Yes, SaintyCo can customize fluid bed dryers to meet your specific design needs.

With the help of a team of engineers having enough experience, you can come up with a special design.

First, SaintyCo will analyze the workability of the design and then make the necessary design corrections.

After that, they will go ahead and produce the custom fluid bed dryer according to your design specifications.

Does SaintyCo Manufacture Multi-Function Fluid Bed Processor?

Multi-function fluid bed processor

Yes, SaintyCo can manufacture multi-function fluid bed processors.

These are fluid bed processors that can perform more than one function.

For instance, you may need a fluid bed processor that can granulate, coat and dry the particles at the same time.

In many cases, the fluid bed processors from SaintyCo are multi-function as you can use them for different purposes.

For instance, you can use a fluid bed processor for mixing, granulating and drying materials at the same time.

Sainty has the right personnel that will assess the design and manufactures the multi-function fluid bed processor.

What is the difference between Tray Drying and FDB?

 Drying trays

Tray drying involves spreading the materials on the tray before you place them in the oven to dry.

The particles will dry up through direct contact between the hot gasses in the oven and the particles.

As it dries off, hot air or drying gasses carries away the vaporized fluids.

The solid particle remains intact on the tray as there will be no suspension into the air.

The solids remain in the dense bed with the particles resting upon one another.

It can dry materials with different moisture contents.

The drying time is a bit long and may take a few hours to a whole day.

In the case of a fluid bed dryer, there is a suspension of particles in hot air streams.

Heat transfer occurs when the solid particles get in direct contact with the hot air.

The drying gases will carry away the vapor from the solids.

The solid material is in an expanded state and they receive more support from drag force in the gas phase.

During the drying process, the solids and gasses intermix and form a bed of floating and boiling the fluid.

Fluid bed dryers often require solid materials with a specific range of moisture content to effectively perform.

The drying time is short and may last between 30 to 90 minutes.

What is Fluid Bed Granulation?

 Fluid bed granulator

Fluid bed granulation is a wet granulation process involving the addition of a binder to independent particles to form aggregates.

Fluid bed granulation aims at improving solid material properties such as flowability and compressibility while avoiding segregation.

You can achieve fluid bed granulation by using a fluid bed granulator.

What are the Benefits of the Fluid Bed Granulator?

In the process of using a fluid bed granulator, you will experience the following advantages:

· Saves Time and Cost

Fluid bed granulators are a one-unit system that will automatically take care of all the granulation processes.

In the process, it will save you time and also an additional cost for hiring extra labor.

· Easy to Handle and Operate

Fluid bed granulators are simple machines with a simple operating system that allows you to operate it with ease.

Most of the functions are automatic thus leaving you with the job of controlling the operating parameters from the control panel.

· Increase in Efficiency and Output

Fluid bed granulators increase the efficiency of granulation hence maximum output.

Heat transfer within the fluid bed granulator is 2 to 6 times greater in comparison to other granulating machines.

· Prevents Mottling

Since both the granulation and drying technique in a fluidized bed processor is uniform, there will be no chances of mottling.

· Low Cost of Maintenance

Fluid bed granulators are durable and have very little downtime during the granulation process.

This reduces the time that you will have to spend doing maintenance.

Apart from that, it will save you a lot of money that you could otherwise spend in doing maintenance.

· Available in Different Varieties

Fluid bed granulators are available in different designs, sizes and capacities to meet your granulation requirements.

· Suitable for Products that are Sensitive to Heat

You can easily granulate products that are sensitive to heat.

Fluid bed granulators have sensors that will control the heat levels for different products thus avoiding damage.

How Does Top Spray Granulation Parameters Affect Material Processing?

Top spray granulation is the most common type of granulation that you can use in the fluid bed granulator.

It consists of three main components that affect the processing of materials.

Top spray system

These include:

· Air Handling System

This system has de-humidification and humidification controls at dew point.

It provides the hot air that blasts and suspends the particle in the air for expansion and granulation processes.

· Product Container and Expansion Chamber

This is the area that handles the products that you need to granulate.

The expansion chamber is the main unit where granulation of solid particles occurs.

· Exhaust System

This includes the processors and the filter housing that blocks any contaminations from entering the system.

It also gets rid of the excess moisture from the system thus allowing the process to continue smoothly.

Apart from that, there are other parameters that will affect the nature of top spray granulation processes,

These include:

· Temperature of Inlet Air

At times the size of granules may reduce as you increase the temperature of the inlet air.

· Volume of Fluidization Air

An increase in the fluidization volume leads to an increase in the particle size.

· Air Pressure for Atomization

An increase in the atomization pressure leads to a decrease in the size of the granules.

· Rate of Spraying Liquid or Binder

An increase in the spraying speed of the binder solution causes the formation of larger than usual granules that are less friable.

How Does Fluid Bed Granulator Compare to Fluid Bed Coating?

Fluid bed coater and granulator

Fluid bed coating is simply the spray coating using a fluidized bed system thus producing an optimal surface coating.

You can achieve this by evenly applying a film coating depending on the coating properties.

The process involves moving the particles around using hot air moving at very high velocities while spraying a liquid.

The organic or aqueous solution evaporates leaving the solid to form a coating layer.

On the other hand, fluid bed granulation is the process where different solid particles bind together to form granules.

The granulation process also involves the suspension of different solid particles by blasting hot gasses over the particles.

The particles will expand and also bombard with other particles thus forming a solid homogenous mixture.

As that continues, the machine will spray a binder to the particles leading to the formation of granules.

The two processes boast of similarities except for the fact that one granulates while the other just forms a coating.

What is the Difference between Rapid Mixer Granulator and Fluid Bed Granulator?

 Rapid mixer granulator

A rapid mixer granulator is a high-speed granulator that assists in blending powder and break granule products to uneven sizes.

You can use it for homogenous and uniform mixing of products to get mixtures of uniform particle size distribution.

It has an air purge sealing system for the granular shaft and the main stirrer drive.

It consists of three main sections including a flat bottom, conical top portion, and a cylindrical mid-portion.

Besides, it also has a counterbalance lid that assists in the efficient mixing operations of different solid particles.

Fluid bed granulators are machines that you can use in the uniform mixing and granulation of different solid particles.

It uses the principle of fluidization to mix and granulate particles to form aggregate granules.

Moreover, it involves the addition of a binder to the process thus facilitating the granulation process.

Apart from granulation, a fluid bed granulator can perform other functions such as eliminating excess moisture from the granules.

How Does Fluidized Bed Granulators Work?

A fluidized bed granulator is multipurpose processing equipment in the pharmaceutical industry for performing different activities.

Step One: Preparation Stage

Frist you need to prepare all the ingredients that you need to granulate and place them in the product tank.

After that, you need to prepare the machine and ensure that it is in a proper working condition.

At the same time, you should remember to set the granulation parameters according to your specifications.

As soon as the preparation stage is over, power the machine and let the granulation process begin.

Step Two: Mixing of the Ingredients

The ingredients will flow from the product tank at specific amounts and into the main expansion chamber.

As soon as the ingredients reach the expansion chamber, allow the hot air to blast through them at specific velocities.

The air will suspend the solid particles into the air and homogenously mix them according to your mixing specifications.

Step Three: Actual Granulation Process

As the hot air passes through the particles, the particles will suspend into the air.

The upward forces and the gravitational forces reach a point of equilibrium and the particles remain floating in the air.

It will form a floating layer that will look like a bed of boiling steam with particle suspensions.

The particles expand and increase in size thus creating enough room for the granulation to occur.

This is the point where you will add the binder which will mix with the particles and allow them to granulate.

Step Four: Drying the Granules

As soon as the granules are in shape, you will stop the spraying of the binder.

The hot air will remain in contact with the granules and eliminate excess moisture within the granules.

Are there Limitations of Fluid Bed Granulators?

Yes, there are limitations to the fluid bed granulators.

Some of the drawbacks of the fluid bed granulators include:

• Impossible to achieve densification

It is not easy to achieve certain degrees of densification in the batch mode of fluidized bed granulators.

• Longer Resident Time

Fluid bed granulators have long resident time that increases the time you spend in the granulation process.

• Use of high amounts of binders

There is a constant need of using higher amounts of granulating liquids in the granulation process.

You have to spray the binder continuously on to the particles as the granulation process continues thus wasting the binders.

• The initial cost of purchase and installation is high

You need to have a huge amount of money to purchase and install a fluid bed granulator.

• The tendency of Filter Clocking

There is a very high tendency of filter demising, clocking and formation of electrostatic charges.

This increases the chances of solvent explosion during the process fluidization.

• Production of low-density granules

The final product or granules from the fluid bed granulators have very low density.

Is Fluid Bed Granulation the Best for Wet Granulation?

Yes, fluid bed granulation is the best for wet granulation.

It increases the granule properties such as compressibility and flowability thus making it the best option.

Apart from that, it makes the final product stable thus preventing it from segregation.

Apart from Fluid Bed Granulators; Which Other Equipment is Suitable for Wet Granulation?

Yes, you can use the fluid bed processors or high shear granulator to assist you with the process of wet granulation.

All you need to do is introduce a spraying nozzle to the equipment and control parameters such as spraying time.

Why is Wet Granulation Important?

Wet Granulation is important because of the following reasons:

• Improves the flowability of the granules

As moisture content increases, the size of granules can easily increase.

This increases the flowability of the final granules such as increasing the flowability of microcrystalline cellulose.

• Improves material densification and compression properties

Wet granulation improves the ability to compress the granules to form certain substances such as tablets.

• Safe to Use

Wet granulation is safe to use as it reduces the emission of dust thus protecting the operator and the environment.

• Increases dispersibility

It improves the dispersibility of the final products as the granule remains more soluble.

• Eliminates Generation of Static Charges

The machine is more efficient and can eliminate the generation and accumulation of static charges.

• Reduces Cross-contamination

Wet granulation reduces the chances of cross-contamination allowing for better powder handling and does not compromise homogeneity.

• Obtaining Homogenous Mixture is Easy

It improves uniformity as it combines different ingredients together through uniform distribution of active ingredients or uniform spraying of actives.

Fluid Bed Granulator has Which Spray Nozzle Designs?

Fluid bed granulators have different spray nozzle designs such as:

Spraying nozzle – Photo courtesy: Research Gate

• Pressure Nozzle

It is capable of breaking up fluid under pressure through its inherent instability, atmospheric impact, and impact on the fixed plate.

• Rotating Nozzle

You can also identify it as a rotary atomizer and you can use it to spray drying applications.

• Airless Spray Nozzle

This nozzle separates the fluid into two streams which you can bring back at the nozzle orifice for impingement from drops.

• Gas Atomizing Nozzle

You can also identify it as the two-fluid nozzle being it the most common spraying nozzle.

It atomizes the binder solution through compressed air

What Affects Choice of Spray Nozzle in Fluid Bed Processor?

You can choose a spray nozzle for your applications by looking at the following considerations:

• Processing option
• Operation mode which can either be batch or continuous
• Application of the equipment
• Processing Principle of the Machine

What is Fluidized Bed Coating?

This is the process by which spray coating occurs in a fluidized bed to create a film coating around solid particles.

It involves moving around different shapes and sizes of particles to form a coating around the solid particles.

Fluid bed coating system

Can you Coat Pellets in Fluid Bed Coating Machine?

Yes, you can coat pellets in a fluid bed coating machine.

A fluid bed coating machine can coat different types of particles such as pellets and granules.

What are the Benefits of Coating using a Fluidized Bed Processor?

The advantages of coating using a fluidized bed processor include:

• Saves time and Cost

The machine is automatic and fast thus saving you time.

Apart from that, it has minimal downtime and you will save a lot on the cost of maintenance.

• Excellent heat exchange and Drying Time

The machine has perfect heat exchange properties that assist in heating the blasting air.

• Easy to clean and maintain

It is easy to clean and maintain the fluid bed coating machine at a very low cost.

• Easy to handle and operate

You can easily handle and operate the fluid bed coating machine since most of the operations are automatic.

What are the Fluidized Bed Coating Applications?

You can use fluidized bed coating in different applications such as:

• Providing a layer that protects the active ingredients from external influence thus increasing the shelf life.
• The shell coating also increases the storage ability of the particles of tablets in the pharmaceutical industry.
• It increases the function ability of the particles such as masking the odor or taste of nasty tasting tablets.

How Does Coating Process in Fluidized Bed Work?

The coating process of particles in the fluidized bed involves the following processes:

First, you need to prepare all the materials and particles by placing them inside the product tank.

The preparation also involves inspecting and setting the coating parameters from the control panel.

As soon as everything is ready, you can power the machine and the process begins.

The particles flow from the product tank into the main chamber where hot air will last the particles at high velocity.

The hot air suspends the particles in the air and maintains them at a particular height in a fluidized state.

At that point, you will spray the coating material straight to the particles depending on the spraying nozzle position.

The spraying material forms around the particles thus making a coat.

After a successful coating process, you will stop the sprayer from spraying the coating material.

The hot air will continue blowing through the particle with the coat and solidify the coat around the particles.

How does Batch and Continuous Fluid Bed Coating Compare?

Continuous fluid bed coating – Photo courtesy: Science Direct

Batch fluid bed coating – Photo courtesy: Science Direct

Batch and continuous fluid bed coating depend on the fluidization principle to assist in the coating process.

Batch coating involves the agglomeration, granulation and coating of particles according to different batch sizes.

It involves the introduction of particles that you need to coat into a cell before fluidizing by an air current.

During batch coating, the coat adheres to the particles and the particles also tend to agglomerate to each other.

Heating and cooling of the particles before coating often happens in different chambers.

Continuous fluid bed coating is suitable for materials with relatively high moisture content

It is able to achieve piston flowability by arranging numbers of partition plates after the second drying chamber.

You can use it in the coating of crystalline materials because it causes destruction to smaller materials.

Heating and cooling of the particles often occur in the same chamber before the coating of the materials occur.

After coating, you can quickly discharge the materials via perforated plates at the end.

What is Würster Coating?

This is the encapsulation of discrete particles in a fluid bed apparatus using varying airflow thus creating cyclic material movement.

It is a unique process because it has the spraying nozzle at the bottom of the fluid bed apparatus.

Why is Würster Coating Critical in Fluid Bed Processor?

The coating process is critical because it provides excellent, efficient, and uniform coating.

It ensures a proper and more uniform coating process leaving all the particles with the same type of coat.

What are the Important Parameters in Fluid Bed Coating Process?

You need to have a keen look at the following parameters during the fluid bed coating process.

These parameters include:

• Inlet temperature

The inlet temperature will depend on the temperature of the product.

You can maintain a constant value through proper volumes of air and the same conditions at dew point.

To avoid the weather effect preconditioning of ambient air to its dew point is important.

Apart from that, you can use very high inlet air temperatures.

• Size of Batch

You should look at the batch size according to the working volume and bulk density of processor.

It will determine whether you are using top spray, bottom spray or the tangential spray.

• Flow of Air

In case you need a satisfactory fluidization behavior, you need to maintain constant volumetric airflow.

You can scale it up based on the change in the area of the distributor plate.

Occlusion of the outlet product bowl or air filter causes resistance to the flow of air.

• Relative Humidity

You should also have a look at the relative humidity in the surrounding working environment.

This includes the relative humidity of wet and dry air leading to a difference in evaporation kinetics.

Residual water in the coating layers can also affect the process of film formation.

• Rate of Spray

You need to look at the size of the droplet or the size of the particles.

To get a similar fluidization level, you need to scale up the multiplier based on the volume of air.

You can as well look at the area of the distribution plate for similar levels of fluidization.

What are the Criteria for Choosing Fluid Bed Processor?

Whenever you are looking for a fluid bed processor, you should look at the following parameters:

 Fluid bed processor design

• Capacity Requirement

You need to look at the capacity of your operation as it will determine the type of fluid bed processor to choose.

For instance, you will go for a fluid bed processor with a top spray if you are operating ate very high capacities.

• Properties of the Raw Materials in Use

A product that has several ingredients with significant differences in bulk densities, you can choose a machine with tangential spray.

• Requirements of Finished Products

You can go for a machine with the bottom spray in case the finished product requirements are very high.

In case of a low budget, you can consider a machine with the top spray which is simpler.

• Process Time or productivity

The type of machine that you are using will determine the quality of the product and the time it will take.

For instance, top sprays are suitable for applications with more time.

For uniform products of high quality, you need to use the bottom spray.

• The versatility of your Application

You should go for a machine that can accommodate varying fluid bed processes.

The machine should be flexible and allow you to make adjustments according to your production requirements.

• Loading or Coating Level

In case you need substrate layered pellets, then you should go for a machine with a bottom sprayer.

The tangential spray is also worthy of high dose loading applications.

Fluid Bed Processors Are Made from Which Material?

The main material in almost all the fluid bed processors is stainless steel.

It is the best material for use on the machine because:

• It is resistant to corrosion.
• It does not contaminate the other materials
• It is easily and readily available.
• It can withstand very high pressure and temperatures from the fluid bed processes.

Why is Quality Standard Compliance Crucial in Fluid Bed Processors?

It is important to adhere to the right quality standards because of the following reasons;

• Quality standards protect the consumer from exploitation by unscrupulous manufacturers dealing in counterfeits.
• It also ensures that the product you are purchasing is safe for the operator and the environment.
• You will also get assurance that the product is durable and of high quality.