Spray Drying Basics

The Basics of Spray Drying

This section is designed to give people new to the field of spray drying basics; a basic understanding of how they work.

A spray dryer is a piece of equipment for rapidly removing moisture from a liquid which can be a soluble solid dissolved in a liquid (a solution), or an insoluble solid suspended in a liquid (a slurry) and producing the solid in a powder form.

In their basic form, Spray Dryers undertake the complete process from accepting liquid feed at one end and packing into sacks or other containers at the other end ready for shipping.

Often on larger plants various processes are added both up and down stream to moderate the processing costs as much as possible. A typical example would be for products such as milk where it’s often economically prudent to put evaporation technologies into the feed system to raise the feed solids as much as possible.

Frequently falling film evaporators are employed to fulfil this duty but there are a wide number of technologies that could be employed dependant upon budget and product. Similarly, fluidised bed technology is often employed downstream allowing material to exit the spray dryer at a higher moisture level for final drying within the more economical fluid bed.

Spray Drying plant comes in many different shapes and sizes and they can look very dissimilar but they all work in basically the same way. Spray Drying is an evaporation process and the most common method of producing powder especially for heat sensitive materials.