What Type of Air Heater Do Flash Dryers Utilize?
As we mentioned last week, there are 4 main dryer systems that use process airs: rotary dryers, pneumatic/flash dryers, spray dryers, and fluidized bed dryers.
This week we will focus on Pneumatic/Flash Dryers (we will refer to them as flash dryers). Flash dryers make up some of the largest dryers in the world! These dryers are used in processes where the feed is susceptible to quick drying. Filter cakes, polymers, granules, and pastes are a few of the products dried using these dryers. The material is dried within seconds when it is mixed with heated air and conveyed through a duct at rapid speeds. As you can tell from the image below, the heated air is generated by a process air heater; typically, direct fired air heaters are used with flash dryers. After going through the drying column, the dried material is then separated using cyclones. A scrubber is also sometimes used in order to meet emission standards.
Check back next week when we discuss spray dryers!