Silicon dioxide (silica) is an oxide of silicon with the chemical formula SiO₂, most known in nature as quartz. It is one of the most abundant minerals present on earth and makes up more than 10% of the earth’s crust. Silica is the major constituent of sand in many parts of the world. It is used in structural materials, microelectronics as an electrical insulator, and in the food, pharmaceutical, and construction industries. Some of the most used applications for synthetic silica are toothpaste and car tires.

However, synthetic silica is used in a wide variety of industries and is formulated in numerous ways for both industrial and consumer applications.

In this article, we’ll talk about:

Types of Silica and Their Usage

1. Precipitated Amorphous Silica

Precipitated amorphous silicas are widely used in a variety of synthetic rubber applications including tires, footwear, technical rubber and silicone rubber. They are effective in rubber formulations to add tear strength, abrasion resistance, and aging resistance.

2. Amorphous Silica

Amorphous silicas are used as a matting agent for wood coatings, roofing, ceiling, and siding of your home.

3. Colloidal Silica

Colloidal silicas are ideal inorganic binders and strengtheners and are used to create gloss on the topcoat of a range of ink types including water-based dyes and pigmented, solvent-based, eco-solvent, and oil-based inks. These silicas can also be applied as a clear surface treatment on paper and linerboard products, resulting in a surface that has improved antiskid and anti-slip properties.

4. Micronized Silica

Micronized silicas are used for refining and processing of edible oils and fats to help improve quality and stability, and to also reduce neutral oil losses. They remove naturally contained and process-induced contaminants such as soaps, phospholipids, and trace metals to ensure food safety. Micronized silicas are also used within the cosmetic industry. Micronized silica particles act as anti-caking and free-flowing agents which help to prevent clumping and caking during processing and storage.

5. Hydrogel Silica

Hydrogel silica is an amorphous, non-crystalline, high-quality gel that is used as a beer stabilizer. This is a highly pure and consistent protein adsorbent that was developed specifically for the brewing process to extend the shelf life of beer without impacting foam and flavor stability.

What special properties does silica have for drying?

Generally, silicas have very small particles that are easy to dry. Their particles do not adhere or bind to each other easily. Silicas can be engineered to have very specific properties, thus making them useful for a variety of applications within many industries.

Advanced Drying Technologies for Silica by Dedert

Dedert provides three innovative drying solutions tailored for silica:

1. Roto-Flash Dryer: An agitated flash dryer, adept at transforming wet feed material into fine powder within seconds, making it economically efficient.
2. Spray Dryer: Primarily used in the food and chemical domains, this dryer turns liquid feed into fine powder, with a particular emphasis on drying silica.
3. Ring Dryer: A versatile industrial dryer that stands out due to its "manifold classifier." It's ideal for drying a wide range of materials, especially silica, and offers additional milling benefits in the airstream.

What is Dedert’s Roto-Flash Dryer and What Does It Dry?

Dedert’s Roto-Flash dryer is an agitated flash dryer. The drying takes place in a cylindrical vertically mounted drying chamber. The rotor-beater assembly provides sufficient force to disperse and break down the wet feed material for drying. The process results in a very fine powder directly from the wet feed material, without the need to pre-mix with already dried product.

The air residence time is only a few seconds, making the Roto-Flash dryer cost effective both in terms of capital expenditure and operating costs.

Dedert’s Roto-Flash feeds cakes/pastes, producing a fine powder with a uniform moisture content and consistent particle size distribution. This dryer typically dries inorganic chemicals such as silica.

What is The Advantage of The Roto-Flash Dryer as It Relates To Particle Size, Bulk Density, etc.?

The Roto-Flash dryer is a high heat transfer system that can do effective drying with a small footprint. One of the main advantages of the Roto-Flash dryer is that it offers milling. The Roto-Flash can break down agglomerates and create very fine particles. As the product dries, it recirculates through the beaters and can break down into small, uniform particles. This is beneficial for the use of silica to produce a fine particle size distribution used in coatings.

The Roto-Flash can also dry thicker and pastier materials like wet cakes and slurries. Bulk density is typically higher than what would be obtained by spray drying.

What is a Spray Dryer and What Does It Dry?

The single-stage spray dryer is the most common and most flexible solution for drying a full range of products for the food and chemical industries. The liquid feed is dried to a fine powder in the drying chamber and discharged from the cone bottom or conveyed with the exhaust air to a primary separator, either cyclones or a dust filter.

When drying silica, the most frequently used type of spray dryer is the single-stage co-current dryer with the rotary atomizer or nozzle atomizer.

What is a Ring Dryer and What Does It Dry?

Ring dryers, also known as pneumatic dryers, are a type of industrial drying equipment that dries a variety of materials. They have a unique feature that sets them apart from typical flash dryers: a “manifold classifier” positioned in the drying system. They are most used within the food, chemical, and pharmaceutical industries to remove moisture from wet materials by applying heat, causing the moisture to evaporate.

When drying silica, it is most common to use the full-ring dryer. The full-ring dryer features a unique manifold design that offers two functions: solids recycle through the hot duct to the air-swept disintegrator; and extended residence time, if necessary, within the manifold to achieve sufficient dryness. This dryer type is particularly useful for challenging drying applications that require extra milling in the airstream.

How Does The Spray Dryer Compare to The Roto-Flash and Ring Dryer?

Spray dried powders are typically larger than what is obtained by the Roto-Flash or ring dryer. Thus, spray dried powders will feature a free-flowing powder due to the particle size, which can be several times larger than what is obtained in the Roto-Flash dryer. The spray dryer feed material must be pumpable and be able to atomize, a requirement not needed for the Roto-Flash nor the ring dryer.

Therefore, operating costs (OPEX) for the spray dryer are higher as more water in the feed is required to make the feed material both pumpable and able to atomize. The spray dryer also produces powders that are less dusty, which is important for reducing potential health risks associated with excess dust post-drying.

Are There Specific End Uses Which Determine The Dryer Type For Silica?

Not necessarily, but Dedert can supply whichever technology our customers want for their specific drying needs. In most cases, the customer will determine which technology they want to purchase with the help of Dedert’s experienced engineers’ suggestions and the use of our testing facility.

Typically, pigment-based silica used in paint products needs small particles which are spheres that result in high gloss coverage paint. Dedert offers multiple technologies to suit this need, including the spray dryer and the Roto-Flash dryer which both produce fine powders with small, uniform particles. Dedert’s Roto-Flash dryer has been used to produce silica that is formulated into toothpaste, where it acts as an abrasive.

What are The Differences Between The Spray Dryer, Roto-Flash Dryer, and Ring Dryer When Drying Silica?

Strengths

Spray Dryer	Ring Dryer	Roto-Flash Dryer
Makes a free-flowing powder	More hygienic than Roto-Flash	More compact system
Most hygienic	Can be configured in many ways (different ring dryers depending on application)	Can accept higher temperatures
Produces bigger particles	Adaptable for milling and non-milling applications	Most economical way to dry silica
		Post-milling is not required
		Produces very fine powders

Challenges

Spray Dryer	Ring Dryer	Roto-Flash Dryer
Must be pumpable and able to atomize, hence lower solids content in the feed is possible	More capital costs- requires more equipment & taller building	Less hygienic- difficult to inspect, clean, etc.
Only use if market requires granule particle size	Requires back mixing of dried material
Limitation on temperature- must use more energy (Lower drying profile is typically possible)
More capital costs- requires more equipment & taller building
More expensive technology
More maintenance

How will the particle requirements determine the type of technology to use?

If the customer’s objective is to dry any type of product size, then Dedert’s Roto-Flash dryer or ring dryer could be used. Once the product is dried, the use of post-milling might be needed to create a much finer powder. For many inorganic products featuring little inter-particle strength, the Roto-Flash dryer will produce a powder with the same primary particle size as is seen in the feed material.

Conclusion

Silica, with its wide range of applications and unique properties, remains indispensable in multiple industries. Dedert, through its cutting-edge drying technologies, caters to these requirements, ensuring optimal results tailored to specific industry needs.

From pharmaceuticals to food processing, fluid bed dryers are revolutionizing drying methods. In numerous industries, the efficient drying of strong materials is crucial for maintaining great product, decreasing manufacturing expenses, and ensuring the highest quality method manipulation. Among the huge range of drying strategies to be had, fluid bed dryers have gained massive popularity due to their versatility, power performance, and advanced drying performance. This complete manual targets to:

• offer an in-depth understanding of fluid bed dryers,
• their operating principle,
• applications,
• advantages,
• and key concerns

What is a Fluid Bed Dryer?

Most dryers use hot air as a drying medium. Dryer designs differ in how the hot air and wet material to be dried interact in the drying equipment. In a fluid bed dryer, the solid particles are suspended in a current of air that is fast enough to make the particles float in the air. A fluid bed dryer is usually some form of metal box with a horizontal perforated plate mounted in it.

Operating Principles of Fluid Bed Dryers

In the world of industrial drying, fluid bed dryers have emerged as highly efficient and versatile systems. Their working principle based on fluidization allows for smooth and uniform drying of solids. In order to optimize drying processes across industries, it is important to understand the basic principles behind them. So, this section of our article will delve into the operating principle of fluid bed dryers, highlighting the key stages and mechanisms involved.

Fluidization: The Foundation

In the core of the fluidized bed dryer lies the concept of fluidization. Fluidization happens when a gas, usually air, passes through a bed of solid particles from below. As the air current gets faster the particles are lifted into the air stream so that there is a mixture of separate particles suspended in the air stream this causes the bed of particles to expand and act like a fluid. There is a range of velocities over which the particles will fluidise. This is called the fluidising velocity.

Generating the Hot Air

The fluid bed drying process begins with a heating step. The drying air is heated to the desired temperature using a heater or heat exchanger. The hot gas is then fed into the lower plenum of the dryer by a set of branched ducting fitted with dampers. These can adjust the amount of air which feeds into each part of the dryer inlet air plenum.

Fluidization of the Bed

A horizontal perforated plate is mounted above the lower air plenum, this distributes the air across the bed of material. The powder which is above the bedplate mixes with the air and this mixture acts like a fluid. Wet powder is fed in at one end of the bed and the height of the fluidized material is maintained by a discharge weir at the other end of the bed where the dried product spills over to the next process.

Heat Transfer and Moisture Removal

In the fluidized state, the particles in the bed are surrounded by hot drying air. This mixture provides greater contact between the heated gas and the wet material, facilitating effective heat transfer and evaporation. The gas transfers its heat energy to the solid particles, evaporating the moisture from the material into the air. to be carried out of the dryer in the exhaust.

Drying in Multiple Stages

The lower plenum can be divided into separate sections each with a different drying inlet temperature or fluidising velocity. This allows for higher temperatures to be used at the feed end of the bed where the product is wetter and lower temperatures in subsequent stages as the surface of the particles becomes dryer. If the product has a high moisture content at the feed end of the bed and much lower product moisture then the fluidising velocity will change as the material progresses down the bed. In this case less airflow would be required as the material passes from one stage to the next.

Cooling Stage

Once the drying process is complete, a controlled flow of cool air may be introduced into a final stage after the drying sections to cool the dried material. This ensures that the product is stable for storage and packaging.

Exhaust Gas Cleaning and Fines Management

During fluidization, finer particles will be blown off the bulk of the product which is fluidized. The upper canopy of the fluid bed is flared to lower the gas velocity and allow some of the fine particles to fall back into the fluidized material. Some fines are always carried out with the exhaust air to the gas cleaning system. In some processes it is desirable to use the fluid bed to separate fines from the bulk of the material by carrying them away in the exhaust. This is called termed elutriation.

Types of Fluid Bed Dryers

Fluid bed dryers can be classified into different types based on their design and operating principles. However, it’s important to note that fluid bed dryers can have modifications and hybrid designs that are suited to certain applications and requirements. The most appropriate kind is determined by considerations such as the material to be dried, required drying qualities, energy efficiency, and process control requirements.

With that said, the main types of fluid bed dryers include:

Conventional Fluid Bed Dryers

Conventional fluid bed dryers have a straightforward design and are frequently used in a variety of industries. They are made out of a perforated bed or plate that holds the material to be dried. The particles fluidize as heated air is supplied from the bed's bottom. After that, the fluidized particles undergo effective heat and mass transmission, resulting in moisture evaporation and drying. Conventional fluid bed dryers are flexible and may be used in various applications.

Vibrating Fluid Bed Dryers

Vibrating fluid bed dryers use extra vibrating mechanisms to improve fluidization. Vibrations are used in these dryers to promote movement of larger particles or sticky wet agglomerates which cannot be fluidized by the air alone. The vibration can also be used to minimize the fluidizing velocity for materials with a wide particle size distribution so that the larger particles are agitated by the vibration and the finer material by the fluidizing air. This will minimize the loss of fines to the exhaust air. In Dedert’s VFBs, vibration is achieved using out of balance vibratory motors and the fluid bed units are mounted on air springs to isolate them from the support structure.

Agitated Fluid Bed Dryers

Agitated fluid bed dryers boost drying efficiency by combining fluidization with mechanical agitation. Within the bed, agitators or stirrers continually agitate the particles. This agitation improves heat and mass transport, resulting in faster drying. Agitated fluid bed dryers are ideal for drying materials with poor fluidization qualities or high moisture content and for uniformly drying cohesive materials.

Use of Exhaust Gas Recycle to Reduce Energy

The principal energy loss from a dryer is generally in the exhaust. One way of improving the energy efficiency is to recycle exhaust gas back to the dryer inlet. This has a few effects:

1. The oxygen content inside the dryer is reduced. This reduces the possibility of explosions or fires.
2. The humidity of the exhaust air is increased. This makes the dryer exhaust suitable for energy recovery by condensing the evaporated water in an evaporator or scrubber.

The energy input to the dryer is reduced.

Applications of Fluid Bed Dryers

Fluid bed dryers have gained increasing popularity in various industries due to their versatility, efficiency, and drying capacity. These dryers have many applications in agriculture, from pharmaceuticals to food processing and minerals. Let's explore the many applications of fluid bed dryers.

Pharmaceutical

Fluid bed dryers play an important role in the pharmaceutical industry, where accurate drying of pharmaceutical powders, granules, and tablets is important. In fact, it is by far the most widely used dryer in the pharmaceutical industry. The main applications are:

Drying of Active Pharmaceutical Ingredients (APIs)	FBD ensures uniform slow drying of APIs, maintaining consistent strength and quality.
Granulation Drying	After the wet granulation process, an FBD is used to dry the granules. This ensures proper particle size distribution and moisture content.
Tablet Drying	FBDs have the capability to effectively remove moisture from tablets without compromising their structural integrity after tablet coating or moisture-sensitive processes.

Chemical

As with the pharmaceutical industry, fluid bed dryers find great utility in the chemical industry for drying various chemical compounds. Some common uses are:

Drying of Chemical Powders	FBDs efficiently dry a wide range of chemical powders, including dyes,pigments,catalysts,and specialty chemicals.
Polymer Drying	The polymer processing industry uses FBDs to remove moisture and solvents from polymer pellets, ensuring consistent quality and performance.
Chemical Reaction Drying	In some chemical reactions, FBDs are used to remove water or other by-products, which helps in the completion of the reaction.

Food Processing Industry

Proper drying of food products is essential for quality and shelf life. This is where fluid bed dryers find their usage in the food processing industry.

Drying Grains and Cereals	FBDs are used to remove moisture from grains, cereals, and seeds to improve product stability and prevent spoilage.
Drying Coffee Beans	During processing, coffee beans need a gentle and uniform drying to preserve their flavor and aroma. FBDs can be configured to do just that.
Drying of Fruits and Vegetable	FBDs are used to remove moisture from fruits and vegetables before further processing or packaging, thus extending the shelf life.

Mineral and Aggregates

Fluid bed dryers find application in the mineral aggregate industry too, for drying and de-agglomerating materials. Key applications include:

Drying Minerals and Ores	FBDs can effectively remove moisture from minerals and aggregates, enhancing their processing and processing properties.
De-agglomeration	In industries where aggregate particles need to be crushed, fluidized bed dryers can provide effective de-aggregation through gentle drying and controlled airflow.

Other Industries

Fluid bed dryers also have applications in many other industries:

Drying Biomass	Moisture removal is crucial for efficient combustion in biomass fuel. FBDs are used in their production.
Recycling and Waste Management	FBDs help to dry and process various waste materials, which enables their conversion into usable products or fuel sources.

Advantages of Fluid Bed Dryers

Fluid bed dryers offer many advantages over other drying methods, making them desirable in many industries. Some key advantages include:

Rapid and Uniform Drying	The fluidization process ensures excellent heat and mass transfer between the gas and the particles. This results in efficient moisture removal and consistent drying throughout the bed.
Gentle Handling	The fluid-like behavior of particles minimizes the risk of material degradation or damage. The gentle handling capability is particularly important for delicate or sensitive materials, such as pharmaceutical powders or fragile food ingredients.
Energy Efficiency	Compared to other drying methods, they consume less energy due to shorter drying times and efficient heat transfer. The direct contact between the drying gas and the particles enables quick moisture evaporation.
Easy Scale-up	These dryers are easily scalable from laboratory-scale to large industrial units. This allows for seamless process optimization and adaptation to changing production requirements. It also facilitates technology transfer from R&D to commercial production.
Versatility	FBDs can handle a wide range of materials with different particle sizes, shapes, and properties. By adjusting the fluidization parameters, such as airflow rate and temperature, FBDs can accommodate various materials, making them versatile for different applications and industries.
Enhanced Product Quality	The controlled drying conditions help maintain the integrity, color, flavor, and other quality attributes of the dried products. The uniform and efficient drying process ensures consistent product quality and reduces the risk of over-drying or under-drying.

Key Considerations When You Opt for a Fluid Bed Dryer

Choosing the right fluid bed dryer is important for optimal drying processes and achieving the desired results in various industries. With so many options available, it is important to consider various factors to ensure that the dryer selected will meet specific requirements.

1.  Material Characteristics

• Particle Size and Shape

Particle size and shape affect the fluidization behavior and drying kinetics. To guarantee efficient fluidization and drying, the dryer must be capable of accepting specified particle properties.

• Moisture Content

The initial moisture content influences drying time and drying factors. It is critical to select a fluid bed dryer that can successfully remove the necessary moisture content in the timeframe specified.

• Heat Sensitivity

Some materials are susceptible to high heat and must be dried at lower temperature to avoid deterioration. In such instances, it is critical to pick a fluid bed drier with accurate temperature control.

2.  Capacity and Throughput

• Drying Capacity

Determine the necessary drying capacity in terms of material weight or volume processed per unit of time. Ensure that the dryer you choose can satisfy your production needs without sacrificing drying efficiency.

• Residence Time

The time necessary for full drying varies according to the material. Choose a fluid bed dryer with enough residence time to enable proper moisture removal without the risk of over or under-drying.

3.  Heating Method

• Energy Efficiency

Assess the heating method's energy efficiency and compatibility with the available energy sources. Choose a heating method that strikes a balance between energy usage and drying efficiency.

• Temperature Control

Assess the heating method's capacity for accurate temperature control. Temperature regulation is crucial for preserving product quality and avoiding overheating or underheating.

4.  Process Control and Automation

• Control System

Analyze the capabilities of the control system to monitor and alter drying parameters such as temperature, airflow rate, and humidity. Look for extensive control options as well as easy-to-use interfaces.

• Automation Capabilities

Consider possibilities for automation, such as programmed recipes, data logging, and remote monitoring. Automation improves process control, decreases human mistakes, and simplifies processes.

5.  Equipment Design and Cleanability

• Construction Materials

Make sure that the materials used in the dryer's construction are appropriate for the purpose, such as stainless steel for the pharmaceutical or food processing sectors.

• Accessibility and Maintenance

Take a look at the ease of access for cleaning and maintenance. Look for features that make cleaning easier and faster, such as detachable parts and easy-to-clean surfaces.

• Air Handling System

To ensure product quality and limit contamination concerns, consider the design of the air handling system, including filtering and exhaust systems.

6.  Safety and Compliance

• Ensure that the selected fluid bed dryer meets relevant safety standards and regulatory requirements. Consider aspects such as explosion-proof design, proper grounding, and compliance with industry-specific regulations.

7.  After-Sales Support and Service

• It is critical to work with a respected manufacturer or supplier who provides complete after-sales support and service. Think about things like warranty, technical assistance, replacement parts availability, and maintenance services.
• This is where Dedert comes in. We are industry veterans in drying technology, and most of our clients are repeat customers. That should give you an idea of our capabilities. A strong focus on customer satisfaction as well as innovation and reliability makes us a trusted partner in the industrial drying industry.

Conclusion

Fluid bed dryers have become incredibly popular across industries for their versatility, energy efficiency, and superior drying performance. Their versatility, energy efficiency, and ability to maintain product quality make them a valuable choice for various industries. But remember, choosing the right equipment is only half the battle. If you know the proper operating and maintenance procedures of these behemoths, they will keep running like new for years to come. Dedert’s decades of expertise can provide you with invaluable assistance in this regard.

A spray dryer is a type of industrial machinery used to turn liquids into powders or granules. This whole thing is done in a single step. The liquid is atomized into tiny droplets, and the moisture is subsequently removed by drying the droplets in a hot air stream. The end result is a fluid powder that is simple to carry and package. In comparison to other drying techniques, spray drying is a common process in the food, pharmaceutical, and chemical sectors because of its high efficiency, adaptability, and consistent product quality.

In this article, we’ll take a look at:

• The history and working principle of spray dryers
• The types of spray dryers and their application
• Advantages, disadvantages of spray drying, and how you can workaround the disadvantages

So, let’s start right at the beginning: a brief history of spray dryers!

History of Spray Drying

A French engineer by the name of Alexis Millardet first employed spray drying in the 19th century to create dried wine yeast for the wine business. But the procedure wasn't commonly used until the middle of the 20th century. In the 1930s, the first spray dryer for use in the industry was created.

Nozzle atomizers were employed in the earliest known spray dryers before rotary atomizers were developed decades later. Very little commercial use of the technology was realized until the 1920s because of the relatively straightforward designs of the first spray dryers and the practical challenges of operating them continually. But since then, this technology has advanced and changed throughout time to fit a wide variety of industries.

How Spray Dryers Work

Now, let’s discuss the working principle of a spray dryer. The most common spray dryers consist of several key components:

• a spray system
• a drying chamber,
• a hot air stream,

and a collection system.

Here’s how they work in harmony:

Feed Preparation	To create the liquid feed, the components are combined, the viscosity is changed, and the mixture is homogenized.
Atomization	First, the liquid to be dried is pumped into the spray nozzle or a spinning disk, where it is atomized into fine droplets.
Dehydrating	The droplets are then introduced into the drying chamber, where they are rapidly dried by the hot air stream. To achieve the correct particle size, morphology, and residual moisture content, the hot air's temperature and flow rate are carefully regulated.
Collection System	The dried powder is then collected by the collection system (typically using centrifugal forces with a cyclone or a bag filter) and may be packaged or further processed.

So, as you can see, the key to the spray drying process is the rapid evaporation of the liquid droplets in the hot air stream. 

The drying rate is influenced by several factors, including:

• size of the droplets,
• temperature,
• velocity of the air, and
• moisture content of the product.

You can choose to control these factors to produce a consistent, high-quality product.

What Are The Types of Spray Dryers?

There are several types of spray dryers available. The type of spray dryer used will depend on the properties of the liquid feed, the desired final product, and the production capacity required.

1. Rotary or Centrifugal Atomization

The rotary atomizer atomizes the liquid supply into droplets using a spinning wheel. This style of spray dryer can produce a large amount of product and is the most flexible atomization system applicable to a wide range of feed materials and can be used on very high viscosity applications. Rotary atomizers can be designed to handle abrasive slurries by use of wheels with ceramic inserts.

2. Pressure Nozzle Atomization

This kind of drier atomizes the liquid into droplets using a high-pressure pump (up to 300 bar) to create a consistent, homogenous powder. Pressure nozzle systems can produce powder with a consistent and narrow particle size which is often required to give good flow properties and consistent bulk density. The food and dairy sectors are the ones that use these dryers the most frequently.

3. Two-fluid Nozzle Atomization

Two fluid nozzles use a gas under pressure (4 to 10 bar) to atomize the liquid. The most frequently used gases are compressed air or steam. The two fluids Gas and liquid feed meet in a small chamber where the high velocity gas breaks up the liquid into fine droplets. This type of nozzle is often used for pilot dryers.

4. Combination of Spray Dryers and Fluidized Beds

Spray dryers are often combined with fluidized beds. The fluid beds can be integrated into the bottom of the spray drying cone with the fluidising air exhausting together with the spray chamber air. Also external fluid bed processors can follow the spray chamber to remove small quantities of moisture and or cool the product. The external fluid beds are often vibrated to help with fluidisation of the product.  These 2 stage and 3 stage drying systems are most often used to produce agglomerated material and eliminate dust.

5. Closed Cycle

These dryers are intended for uses where the product is susceptible to oxidation or the solvent is not water but an organic liquid which has a flammable vapour. The drying procedure is carried out in a closed loop, using nitrogen as the drying medium instead of air to exclude oxygen from the drying process. A cooler/condenser is used in the closed loop to recover the sovent.

What Are The Advantages of Spray Drying?

One of the main advantages of spray drying is its ability to produce a free-flowing powder that is easy to handle and transport in one processing stage. Spray drying itself is not the lowest cost method of production but it can produce a powder directly from a liquid in one step. Most other methods would use multiple steps (ie dewatering and fluid bed or flash drying) For this reason when operating small production plants or pilot systems a spray dryer usually means less capital cost even though the operating cost may be higher.

However, there are many other advantages to using a spray drying method.

1. Flexibility

One of the most significant benefits of spray drying is its ability to produce a powder from a liquid feed. Spray drying is thus a cost-effective way for creating a wide range of products such as food ingredients, pharmaceuticals, chemicals, and cosmetics.

Because the approach is so widely used, you can choose high-quality, dependable components for optimal service life and availability. Often spray drying is used when developing new products as it can be applied with a relatively short development programme.

2. Superior Product Quality

Particles produced by spray drying are distinguished by their uniform particle size and stability. This higher level of product quality is crucial in a variety of industries, including food, medicines, and cosmetics. The homogeneous particle size of spray-dried powders makes them excellent for use in the manufacture of these products, as they are easier to process and have better flow properties.

End-to-end traceability in accordance with current food standards and laws is also enabled via automated process control.

3. Preservation of Active Ingredients

The potency and efficacy of active compounds must be preserved in industries such as pharmaceuticals and biotechnology. Spray drying preserves these active components, making it a suitable method for manufacturing high-quality pharmaceuticals and biopharmaceuticals.

4. Versatility

Another benefit of spray drying is its customization. This procedure is suitable for a wide range of liquids and suspensions, making it an excellent way for drying a wide range of items. Spray drying's adaptability enables the creation of a diverse spectrum of powders, including food additives, pharmaceuticals, chemicals, and cosmetics.

5. Reduction of Contaminants

Spray drying can also help to reduce contaminants like bacteria and other microbes. This is especially critical in industries such as food and pharmaceuticals, where the presence of contaminants can lead to the degradation of product quality. Spray dryers most often supplied with CIP (Clean In Place) systems and designed with smooth interior surfaces for easy cleaning.

What Are The Industrial Applications of Spray Dryers?

The advantages of spray drying should already tell you how versatile the solution is for a wide range of industries. So, let’s take a look at the industries that use them.

1. Food

The food business is one of the largest purchasers of spray drying technology. It is often used to make instant coffee, tea, milk powders, egg products, infant formula, flavours and other food ingredients. Spray drying preserves the flavour, aroma, and color of the food while minimizing bacteria and other contaminants. The process's great speed and efficiency result in a cost-effective technique for generating huge amounts of food ingredients.

2. Pharmaceutical

As we mentioned earlier, the pharmaceutical industry is also a large consumer of spray drying technology. These industries use it to create powders, granules, and tablets, as well as to encapsulate active substances. The consistent particle size and stability of spray-dried powders make them excellent for use in the production of medicinal products. 

Furthermore, the technique preserves the strength and usefulness of the active components, making it a suitable method for producing high-quality pharmaceutical goods.

3. Chemical

Spray drying technology is also widely used in the chemical industry. This method is used to create catalysts, pigments, detergents, and other chemical products. Spray drying is also used in the drying of solvents and other chemical solutions in this business. Spray-dried powders are suited for usage as catalysts, pigments, and other chemical products due to their uniform particle size and stability.

4. Agricultural

The agricultural industry benefits a lot from spray drying tech. This method is used to make animal feed, fertilizer, and pesticides. Because of the high speed and effectiveness of spray drying, it is a cost-effective approach for creating large numbers of these items. Furthermore, the consistent particle size and stability of spray-dried powders make them perfect for usage as animal feed, fertilizer, and pesticide products.

5. Biotechnology

The biotechnology industry is another large consumer of spray drying technology. Creating recombinant proteins, vaccines, and other biopharmaceuticals became much easier once we introduced spray drying in this industry. The potency and efficacy of active chemicals must be preserved in this industry, and spray drying enables for the manufacturing of high-quality biopharmaceuticals.

6. Environmental

The environmental industry uses spray drying technology by processing the treatment of wastewater, solid waste, and air pollution. The efficiency and versatility of spray drying make it an ideal method for treating these types of waste products.

7. Cosmetic

You may have already guessed that the cosmetic industry also uses spray drying technology since many products in this industry involves particles. Thus, this type of process is used for the production of cosmetic powders and other personal care products. However, rather than spray drying, we use a spray cooling process because the products used for skincare are usually fats and melt at a low temperature. In this case, the materials are melted to form a liquid and then fed to the atomization system as a molten liquid. The spray is discharged into a cold air stream and solidifies into solid droplets forming a dry powder which is easy to handle.

8. Materials for Lithium Ion Batteries

A growing market for spray drying is the production of powder for the production of cathode and anode materials for EV battery production. This is a new field requiring new forms of atomization and drying to produce materials with a high surface area to give the best battery performance.

What Are The Disadvantages of Spray Drying?

No tech is without disadvantages. Spray drying technology is no exception. Here are some disadvantages associated with spray drying:

Limited feed viscosity	Typically, only feedstocks with a viscosity lower than 500 centipoises can be dried using spray technology. This means that it is necessary to dry at relatively low solids in the feed material. Sometimes the feed must be diluted to achieve the correct viscosity. Other methods of drying can handle much higher solids concentrations and so reduce the size of the dryer.
High Capital Cost	It’s an expensive tech to purchase and operate because of the high evaporation rate in relation to other systems.
High energy consumption	The heating of the air stream and atomization of the feed during spray drying consumes a lot of energy. Especially for large-scale operations, spray drying may be expensive due to its high energy usage.
Operational Safety	Many of the materials produced as dry powders are explosive and or flammable. Spray dryer systems are provided with explosion protection systems and fire safety systems design to safely eliminate any danger of deflagration. These are some of the most important parts of the equipment design.

You’ve read about the disadvantages of spray dryers. But despite these limitations, the return on investment in spray drying tech is way too profitable to pass on. Plus, in some cases, there’s little to no other alternative to this tech. Adding to this is the fact that since spray drying is so widely available, it is developing at a very fast rate where most of these disadvantages are mitigated by newer innovations in this field to a large enough level.

How to Make Spray Drying Viable for Your Business?

To continue with our above argument, if you buy your equipment from the right sources, your installations will have the unparalleled cost-benefit that spray dryers are famous for.

Have a look at Dedert’s innovative spray drying technology. The revolutionary, patented high-speed rotary atomizer serves as the foundation for Dedert's new line of spray dryers. The innovative rotary design, which is based on magnetic bearing technology, offers unmatched flexibility for the most demanding applications by doing away with the requirement for high-maintenance gear drives, bearings, shafts, oil lubrication, and cooling systems.

What’s more, is that they are immediately compatible with existing installations on top of being easy to maintain and service. So this is where you can recoup a large portion of your investment quite efficiently.

Conclusion

In conclusion, spray drying is now a ‘household’ name in many industries. It has various benefits over other drying techniques. It may have its complexity and high level of technical skill requirement, but the benefits far outweigh its quirks. However, as with any industry, you may need to thoroughly weigh the advantages over the disadvantages of spray drying and see if it suits your application.

FAQs