Adiabatic dryers obtain their heat from the hot air, which enters them and uses the sensitive heat to vaporize the moisture from the process solids. The heating air enters a dryer at some high temperature and leaves at an outlet temperature which is low at the beginning of a batch drying cycle and rises as the solids heat up and dry. In continuous adiabatic fluidized bed dryers the average moisture content of the solids in the bed is almost the same as the moisture content of the product. The latter is a combination of temperature difference between the product and the surroundings and the moisture content of the dryer atmosphere. Empirical runs can be made to establish dryness of a product with given feed and dryer characteristics so that operating curves can be developed. The term “atmospheric dryer” designates a batch dryer that operates at close to atmospheric pressure and obtains the heat for drying from the hot air supply.