A flash dryer is a type of machinery that is able to quickly dry materials without causing clumping or contamination. These machines are able to use a wide range of temperatures and drying gases to adjust to the chemical make up of whatever is being dried. They are used frequently to de-agglomerate materials. This means that moist materials such as those found in a slurry feed can be quickly dried in a way that allows the particles to separate rather than fuse. Since the temperature and type of gas used in this process can be easily adjusted sensitive particles are not damaged or changed while being dried.
How Flash Drying Works
The exact way that flash drying works depends on the type of dryer used. Usually these dryers are designed with a recirculating loop. The mechanism works by using a combination of temperature and air pressure. The process takes place in multiple steps. In the first step low pressure air, steam, or inert gas are used to de-agglomerate materials and move them through a drying circuit. A heated drying medium is then run through a chamber at high velocity to create a turbulent flow pattern. This movement causes particles to crash into one another. As they crash, they break apart. Every time a particle is broken the surface area increases, exposing more surface to the drying mechanism. This is one of the fastest ways to dry a particle because it improves the efficiency of heat transfer. While particles are colliding and heat is being transferred, a centrifugal force is used to separate dry particles that have reached the ideal size. Heavier particles that have not been fully separated or are still damp are kept in the drying chamber and the process continues. When the drying process is complete, a cyclone can be used to separate particles form the air stream.
Benefits of Flash Drying
Flash drying is not always necessary, but it can be extremely beneficial for the production of pure, finely ground particulates. This system works well because it can be adjusted to accommodate the exact material being used. It can dry heat-sensitive materials without degradation and improve purity while quickly sifting components into necessary particle sizes. Flash drying is most frequently used to dry things like: chemicals, polymers, pigments, ceramics, sludge, and minerals. Manufacturers of any of these products can benefit from using a flash dryer because doing so combines the process of drying and milling which eliminates a step in the particle production process. Flash drying also improves product purity and reduces contamination and product malfunction that can occur when mechanical drying and milling methods are used.