Considerations In Choosing A Rotary Dryer


There are a number of factors to consider when choosing […]

There are a number of factors to consider when choosing the best rotary dryer for your specific needs. Some of these include:

Direct or Indirect Heat?

There are two main designs for rotary dryers when it comes to the application of heat. Direct heat rotary dryers pass a stream of drying air through the drum. The drying air is directed in either a co-current flow (flowing the same direction as the material), or counter-current flow (moving in the opposite direction of the material).

Direct dryers are the most common choice for drying bulk solids, because they are so efficient. However, there may be cases where direct heat is not an option. If the material to be processed is eventually going to be used in creating consumer products, it may not be appropriate for those materials to come into contact with the combustion gases of a directly heated rotary dryer. There may also be cases where the material to be processed cannot come into contact with oxygen, or needs a completely inert environment. In cases such as these, an indirectly heated rotary dryer is the answer. This configuration transfers heat into the chamber via the shell of the rotary dryer itself. This method also avoids the risk of material becoming entrained in the drying air, which can be a challenge when working with fine materials.

Operational Surroundings

Another factor to consider in choosing a rotary dryer is the location of the operation. Things such as the surrounding atmosphere, air temperature, humidity, and elevation, can all affect the dryer’s performance. For example, an increase in elevation means a decrease in the amount of oxygen in the atmosphere, making the air less dense, and less combustible. At higher elevations, therefore, the dryer’s fan size may need to be increased to compensate.

Rotary dryers are useful in a variety of industrial applications and choosing the right dryer can enhance the efficiency of your entire materials processing system.

A Customized Drying Solution

It is important to keep in mind that a variety of factors will influence the success of the drying process. In addition to the processing environment, many material characteristics will affect how the material responds to drying, and subsequently, how the dryer will need to be designed in order to work around those characteristics to produce a product with the desired specifications. Characteristics such as bulk density, angle of repose, moisture content, and more, will all need to factor into the design of the rotary dryer itself. When choosing a rotary dryer that will meet your process and product goals, customized equipment will produce the best results.