Summer Special | Get 50% Off | Code #GET50
Spray Drying

Is Your Product a Candidate for Spray Drying?

Spray drying has become the preferred method for drying heat-sensitive materials. First developed in the late 19th century, it’s an efficient way to convert liquids to fine dried powders, and it has multiple advantages. For example, dried forms of a sample or product are usually stable and can be stored in inventory for longer periods. And since they weigh less, the cost to transport each unit is lower. Spray drying is used for food and dairy, pharmaceutical, agricultural, and industrial samples and products. Milk was first spray dried to a powder form about 70 years ago.

The spray drying process starts by pre-conditioning the liquid that will be dried to increase its solid content and reduce the amount of liquid that needs to be evaporated. This suspension is pumped into a drying chamber through a feed nozzle and mixed with a continuous flow of gas. The suspension undergoes atomization, which creates the optimal condition for evaporation. Fine droplets are produced by the atomization, and these contact or attach to the heated glass drying chamber. The flow of gas achieves a cyclone effect, which separates the dried particle from the gas and deposits the particle into a powder collection vessel.

The primary components of a spray dryer system are its pump, air compressor, heaters, nozzles with critical orifice, needle valves, drying chambers and collection flasks. For samples or suspensions with inorganic solvent content, nitrogen-inerting and solvent recovery systems are added to allow safe drying. The final product’s particle size, bulk density, crystallinity, organic impurities, and residual solvents are determined by the type of spray dryer, nozzles and specific cycle parameters that are used.

Will it work for you?

When considering spray drying as a process solution for your product or sample, think about the desired end point and final product. Here are some questions to consider:

  • What is the required particle size?

  • Is the sample hygroscopic (does it absorb moisture from the air)?

  • Is the sample water soluble? Oil soluble?

  • What temperature profile is required?

  • What is the viscosity of the liquid slurry?

  • How much solid content is in the feed?

  • Is the liquid feed material a solution or a dispersion?

  • Should the finished product be hydrophilic (easily wetted by water), flowable or tacky?

Specifying and selecting the correct spray dryer for your requirements is a relatively easy process. Once you have the answers to the above questions, the next step is to complete a spray dryer survey and submit it to the spray dryer manufacturer for review. Most often, the survey responses provide enough information to identify the proper spray dryer and accessories. If any questions remain about the process, some companies offer a sample test run at their facilities to finalize the process and equipment. There may be a modest fee for sample testing, but this service will mitigate risk. 

Go for quality and experience

To assure a spray drying process that maintains its efficiency and quality over time, look for a manufacturer with significant experience in the successful development and sale of spray drying equipment. A company that offers reliable options for various industries, price points, production capacities and product requirements will provide the best value and the best purchasing experience. Another major consideration is the quality of their service, which will help you maintain optimal performance over the life of your equipment. If spray drying is for you, Acumen Technology can connect you to such a provider.

Patience for the People