The basic principle of spray drying hinges on water removal but how you remove that water can make a significant difference on the product quality.
Spray Drying Factors
Many spray drying factors must be considered when selecting the best method to produce your dry powder. A primary start would be determine product moisture and particle size requirement as this can impact atomizer choice. For example, an atomizer wheel will give you a wider distribution of particle size while a nozzle will give you narrower distribution. Selecting the right atomizer can also impact your product color as particle size and color are intertwined. Furthermore, if a nozzle is chosen, is the nozzle being used as part of a co-current flow or counter-current flow is another variable to consider as residence time in the dryer and particle size of the powder are impacted.
Another factor to consider is the type of dryer you are using. If the dryer is a tall form dryer than you have more surface area for drying which will help with achieving product specs. Does the dryer have a cylindrical or conical bottom? Depending on this configuration, drying can be impacted due to surface area considerations. Aside from surface area creating an impact, the dryer configuration can also impact product yield and cleaning time resulting in cost considerations.
Upstream Processing in Spray Drying
Upstream processing is as crucial to the spray drying process as is the actual spray drying. Order of addition of raw materials can impact the viability of the emulsion or solution to be spray dried. Slurry temperature can also impact the viscosity of the material to be pumped. Too fast or two slow a pump rate can also impact how well the product dries in the spray dryer. If the emulsion is homogenized, the size of the micelle can also impact spray drying along with shelf life in the future.
These are just some of the basic variables to look at when evaluating spray drying as a means to produce your powder. Learn more about spray Drying in our Spray Drying Webinar.