When it comes to spray drying, I often get questions when a spray dryer gets changed from a product for which it was originally designed to a new product. Usually the question goes something like, “I used to get X pounds per hour of capacity on the old product, but now I only get 75% of the original capacity. What’s happened?”
Spray drying is a thermodynamic process. The difference between dryer inlet temperature and dryer outlet temperature is the main driver in capacity. Dryer inlet temperature is limited by two main factors: a) the maximum temperature that the product can withstand without product degradation or a safety issue and b) the maximum absolute moisture in the dryer outlet air. The dryer outlet temperature is also firmly tied to the nature of the product and the humidity at which non-sticky powder particles are produced. Changing the product leads to changing the parameters at which the product can be dried and therefore the capacity.
But there are several other factors that also need to be considered, predominantly having to do with product make-up. This is especially true if the original or new product is a complex mixture of proteins, carbohydrates and fats, like dairy powders or nutritional formulas.
And on a very serious note, changing products also requires a dryer safety assessment. Powders are the fuel for possible fires and explosions in your spray dryer. Each powder should be tested for its likelihood to burn or conflagrate, and the speed at which it burns. Your spray dryer was likely designed for a specific product, and a change in product may take the equipment outside of the safety parameters for which it was designed. You may not have enough overpressure venting panels, or your explosion suppression system may not be large enough to handle a stronger explosion. This is important for both equipment and personnel safety.
Caloris can help with all these complex questions about your spray dryer and potential product changes. We can answer the same for your evaporator and membrane filtration systems as well. Learn more about Caloris spray drying here or give us a call.
This blog post was written by Caloris Business Development Manager and Spray Dryer Expert Jim Kent. You can contact Jim via email for more information or call Caloris at 410-822-6900.