Spray drying is an indispensable technology in many fields, including food, pharmaceuticals, and chemicals. It provides consistent powder quality and higher production efficiency. However, this technology was not perfect from the very beginning. Tracing the history of spray drying and understanding how the technology has overcome challenges can help you choose the spray dryer that best suits your production line.
What Is Spray Drying?
Spray drying is a method of converting liquid materials into dry powders. The main steps of the spray drying process involve atomizing the liquid material into fine droplets and exposing them to hot air, causing the water or solvent to evaporate rapidly. This produces a dry final product in the form of powder, granules, or hollow spheres.
Because the drying time is short and the evaporation process itself produces a cooling effect, spray drying is an excellent choice for processing heat-sensitive materials. Furthermore, the process is simple and requires little manual intervention, making it highly suitable for large-scale, continuous industrial production.
The Origins of Spray Drying Technology
In 1865, Charles A. La Mont first applied spray drying to the processing of egg liquid. This is the earliest recorded practical application of this technology. In 1872, American inventor Samuel Percy formally filed a patent application for spray drying technology. Percy studied the drying of solutions of dextrin, starch, and gelatin, and claimed that the method could produce powdered products while minimizing chemical changes and reducing moisture content.
In 1888, spray drying technology was used in the production of powdered milk and glucose. This marked its first commercial application.
The Rise of Industrial Spray Drying
Are you concerned that highly viscous materials might clog the nozzle? This was precisely the challenge people faced in the past. Early spray dryers used nozzle atomizers. When processing high-viscosity materials or suspensions containing fine particles, the nozzles were prone to clogging. This led to frequent production line shutdowns for maintenance, severely reducing production efficiency.
It wasn’t until 1924 that Johan Ernst Nyrop invented the rotary atomizer (also known as a disc atomizer). It features a rotating disc that can spin at speeds of 10,000–30,000 RPM. It uses the centrifugal force generated by rotation to fling the liquid into extremely fine droplets. This method completely overcomes the physical limitations of tiny spray holes and reduces the risk of clogging.
Today, rotary atomizers are still widely used. If you need to process high-viscosity, high-solids, or crystallizing materials, this type of atomizer is a good choice.
Expansion of Spray Drying into New Industries
In the 1860s- 1880s, spray drying in pharmaceutical industry faced new challenges. With the development of the technology, many materials needed to be dissolved in organic solvents. However, traditional open systems used air as a drying medium, which made them prone to organic solvent explosions. The direct release of organic solvents also caused severe pollution and costly waste of raw materials.
To address this challenge, the closed-cycle (also called inert loop) system was developed. This system uses an inert gas, such as nitrogen, to replace air for drying. This eliminates the conditions for deflagration. The system maintains a slight positive pressure internally and is equipped with a condenser, which recovers and reuses solvents and nitrogen. This protects the environment while also reducing production costs.
If your material contains organic solvent, just choose a spray dryer with a closed-cycle system. Today’s closed-cycle systems can achieve product yields and solvent recovery rates exceeding 98% and 99%.
Advanced Spray Drying Technology Today
With advances in technology, spray drying has now become a well-established process. This section will introduce you to some advanced spray drying technologies, which you can use as a reference and select based on your specific production needs.
Low Temperature Vacuum Spray Drying
Vacuum spray dryers utilize a vacuum pump to reduce the system pressure inside the drying tower. The boiling point of water decreases under low pressure, enabling rapid evaporation of moisture at temperatures between 40°C and 80°C.
Vacuum spray drying technology effectively protects heat-sensitive active ingredients and improves product quality. It is particularly well-suited for processing products such as probiotic powders and vitamin powders.
Cutting-Edge Atomization Techniques
Ultrasonic Atomizer
This atomization method uses high-frequency ultrasound to produce uniform, fine droplets, making it particularly suitable for the production of micron- and nanoscale drugs. Ultrasonic atomizers can also be used for low-pressure spray drying, ensuring a fine product texture while helping to minimize thermal damage to the material.
Microfluidic Atomizer
The Microfluidic Atomizer limits crystal growth through an extremely rapid solvent evaporation rate, thereby producing extremely small sizes (< 30 μm or even smaller) with uniform particle size distribution. It also enables precise control over particle morphology, crystal form, and structure.
It is commonly used in the production of poorly soluble drugs, such as Fenofibrate and Clotrimazole, to increase their solubility. You can also use it in the production of inhaled medications like Budesonide.
Electrohydrodynamic Atomization / Electrospray
This atomizer uses electric field forces to disperse liquid into nano-sized charged droplets. Electric field technology has been proven to accelerate droplet evaporation, increase drying rates, and improve product quality. It requires only very low heat to evaporate moisture, making it suitable for the production of highly heat-sensitive biopharmaceuticals, gene vectors, and nano-drug delivery systems.
Programmable Logic Controller Systems
Today’s industrial spray dryers feature advanced PLC/HMI controls with closed-loop PID systems to maintain precise thermal stability and atomization accuracy.
Beyond automated recipe selection, real-time trend monitoring, and safety alarm interlocks, modern control architectures ensure strict batch repeatability. They support comprehensive data logging, audit trails, and FDA 21 CFR Part 11 / cGMP compliance to guarantee complete data integrity and full process traceability.
These intelligent units can also integrate into plant-wide SCADA or DCS networks for centralized industrial operational monitoring.
Heat Recovery Systems
Heat recovery systems significantly reduce energy consumption by recovering waste heat from exhaust gases to preheat incoming air. Typical industrial-grade heat recovery solutions use H-type elliptical finned tube heat exchangers or water-based heat exchangers to capture waste heat energy from exhaust gases. This not only helps you save on fuel costs but also reduces pollution caused by flue gas emissions.
Lab-Scale Spray Dryers
If your product is in the R&D phase, we highly recommend choosing lab-scale spray dryers. In fact, prototypes of cyclone-type laboratory spray dryers appeared as early as 1943. However, modern laboratory equipment enables researchers to validate process feasibility and optimize formulation parameters using smaller sample sizes, as little as a few grams.
This helps you avoid the high costs associated with trial and error, making it the ideal choice for the R&D of high-value active pharmaceutical ingredients and biopharmaceuticals.
FAQ
What Are the Main Types of Spray Drying Machines?
The main types of spray dryers vary depending on the classification criteria. Based on atomization mode, they are categorized into rotary, pressure nozzle, and two‑fluid nozzle types. Based on gas‑liquid flow direction, they are divided into co‑current, counter‑current, and mixed‑flow types. Based on the system circuit, there are the open‑loop type and the inert‑loop type dedicated to organic solvents. Based on operating pressure, they can also be classified into atmospheric‑pressure type and low‑temperature vacuum spray dryer type.
How Do I Accurately Scale Up Processing Parameters from a Lab-Scale Spray Dryer to a Pilot or Industrial Unit?
When scaling up spray‑drying processes, do not simply enlarge equipment volume and feed flow rate. The core requirement is to keep heating, evaporation, and flow conditions largely consistent with lab‑scale setups. Maintain a fixed droplet size and atomization energy intensity, and align the relative hot‑air‑droplet flow velocity within the tower with the drying rates, while preserving proportionality of the parameters. We recommend that you conduct pilot‑scale trials before investment, as they substantially mitigate risks when procuring full‑scale industrial spray‑drying units.
What Are the Advantages of Spray Drying Milk?
Compared to liquid milk, spray-dried milk can be stored for a longer period at room temperature. Because of its reduced volume and weight, spray-dried milk incurs lower logistics and storage costs. At the same time, the high degree of controllability in the spray drying process allows for precise adjustment of the milk powder’s particle size distribution, bulk density, and wettability. It also maximizes the retention of heat-sensitive nutrients, such as immunoglobulins, providing high-quality industrial raw materials for subsequent applications. Pilotech offers professional milk spray dryers. Click for more details.
How Can I Prevent the Degradation of Heat-Sensitive Active Ingredients during High-Temperature Spray Drying?
Activity can be protected in the following ways. First, by using a co-current design, high-moisture droplets come into contact with the highest inlet air temperature, and the cooling effect of wet-bulb evaporation protects the material. Second, optimize atomization to reduce particle size and increase the air flow rate. This helps shorten the residence time. You can also add coating materials such as maltodextrin for microencapsulation, or directly use low-temperature vacuum spray drying technology.
What Is Spray Drying Microencapsulation?
Spray drying microencapsulation is a process in which active ingredients (core material) are combined with a polymeric carrier (wall/matrix material) to form an emulsion or suspension. Then, through atomization and evaporation, the active ingredients are instantly encapsulated within solid microspheres. This technology effectively isolates the active ingredients from oxygen and light, masks undesirable flavors, and prevents the loss of volatile components. It also enables the controlled-rate release of active substances such as probiotics, oils, and APIs.
What Is the Difference between Spray Drying and Freeze Drying?
Spray drying uses hot air to instantly evaporate moisture. It offers extremely high production efficiency, lower costs, continuous operation, and easy control of particle size, making it suitable for large-scale production. Freeze drying requires the material to be frozen before sublimation. It causes no heat damage and maximizes the retention of three-dimensional structure and bioactivity. However, the equipment is expensive. The process also takes a very long time, and energy consumption is extremely high. For heat-sensitive materials, modern low-temperature spray drying has become a low-cost alternative to freeze drying.
How to Choose the Most Suitable Spray Dryer?
Equipment selection requires a comprehensive evaluation across four key dimensions. First is material characteristics. This includes heat sensitivity, viscosity, and whether the material contains organic solvents (which determines whether a nitrogen inert loop is required). Second is product requirements, such as particle size distribution (PSD), bulk density, and solubility. Third is production scale. Processing capacity must be matched to the specific scale, ranging from lab scale to industrial-scale production. Fourth is compliance and safety, such as explosion-proof standards (ATEX/NFPA) and cGMP clean-in-place (CIP) requirements.
Final Thoughts
Understanding the history of spray drying can help you optimize your existing technology and encourage you to embrace new technological trends actively. Pilotech is a professional manufacturer of spray dryers, and we offer a wide range of spray drying solutions. If you have any questions, please feel free to contact us at any time!