Maximizing surface-to-volume ratio: Rotating indirect-heat dryers
A rotating indirect-heat dryer reduces moisture levels in various materials during processing. The dryer vessel's configuration determines the available surface-to-volume ratio and predicts the degree of agitation and particle degradation that will occur in the drying cycle. After explaining how drying works, this article discusses the operation and application of three types of rotating indirect-heat dryers: batch, extended-surface batch, and continuous.
When a material exits a reaction or process at a higher moisture [or solvent] level than you desire, you can remove some of the moisture mechanically by simply pressing the material. But ensuring the material -- whether a raw material, a chemical intermediate, or a final product -- is dry enough for your specifications typically requires you to apply heat energy with a dryer.