Vacuum drying methods are integral to the chemical process industries (CPI), enabling the drying of sensitive materials without compromising critical properties. Heat-sensitive intermediates and pre-clinical active pharmaceutical ingredients (APIs) often necessitate such methods, as they are unsuitable for high-temperature convection processes.
Image Credit: Powder Systems
Highly valuable compounds must be gently dried; otherwise, they may degrade. Any loss of quality across drug pipelines can naturally lead to wasted resources and higher costs. Therefore, vacuum drying ovens are prevalent in pharmaceutical laboratories, pilot plants, and commercial-scale facilities.
This article will provide an overview of the working principles of vacuum drying processes, focusing on how vacuum tray dryers work.
The Basics of Vacuum Drying
Drying is a simple process. The temperature inside a drying chamber is increased to the solvent boiling point, providing heat to a moist feedstock until any liquid within vaporizes. Free moisture on the surface evaporates fairly quickly, while bound moisture in the product has to first escape the solid microstructure.
This form of heat transfer offers a challenge as the feedstock must be exposed to relatively high temperatures. Inducing vacuum conditions allows the same process but at lower temperatures, protecting sensitive compounds from heat damage.
As opposed to a convection oven, the feedstock in a vacuum tray dryer is not immersed in heated environments as vacuum technology pushes hot fluid through direct heating shelves. Instead, the feedstock temperature is increased through conduction.
The low-pressure environment heats the products, and reduces the solvent’s boiling point to aid with highly efficient, low-temperature drying that is completed at faster rates.
Image Credit: Powder Systems
Image Credit: Powder Systems
Important Considerations with Vacuum Tray Dryers
While several new methods have emerged, vacuum tray dryers continue to serve as a fundamental tool in CPI, renowned for their exceptional reliability and efficiency. However, selecting a drying system involves multiple considerations, as there is no one-size-fits-all solution.
- Batch size
- Moisture content
- Liquid properties
- Temperature uniformity
- The ratio of bound to free liquid
- Vapor pressure profile under use conditions
- Explosive Atmosphere (ATEX, NFPA)
These considerations should be resolved through rigorous testing and through discussions with a reputable systems integrator.
Looking for Vacuum Tray Dryers?
Powder Systems Ltd provides meticulously designed vacuum tray drying solutions that effectively address common challenges encountered in kilo to large-scale productions. For those seeking a comprehensive solution spanning lab, pilot, and commercial scales, the CakeStandTM vacuum tray dryer is an all-in-one option.
Beyond offering innovative technologies, Powder Systems Ltd is uniquely equipped to provide on-site servicing, installation, and ongoing support, ensuring that its vacuum tray dryers are ideally suited to each application.
This information has been sourced, reviewed and adapted from materials provided by Powder Systems.
For more information on this source, please visit Powder Systems.