Process for thermal treatment, especially drying

Abstract

The invention relates to the thermal treatment of flowable material using heated contact surfaces in a fluidized bed. Known processes use a gas, often air, to fluidize the bed. This imposes limits on the temperatures that can be allowed to be reached as higher temperatures can cause the material to be treated to burn. It also often produces sterilization of the material. Further there is the problem of disposal of the gases generated in the treatment process. In an attempt to alleviate these problems, the present invention proposes a process generally of the above kind but in which the fluidizing gas comprises gases generated in the bed itself. This is economical as it reduces the heat losses, environmentally desirable as it reduces the amount of gas discharge and more efficient as these gases are generally inert, thus enabling higher temperatures to be generated in the bed without risk of the material burning, thus also facilitating sterilization of the material.

Dependencies are inferred from the claim text.