Thermal regeneration is the most widely used and the most mature method for the regeneration of activated carbon in industry. It is generally divided into three stages: drying, high temperature carbonization and activation.
In the drying stage, the volatile components on activated carbon are mainly removed. In the high temperature carbonization stage, part of the organic matter adsorbed on the activated carbon is boiled and vaporized, and part of the organic matter is decomposed, resulting in small molecular organic matter desorption, and the residual components remain in the pores of the activated carbon to become "fixed carbon". At this stage, the temperature will reach 800 ℃ and 900 ℃.
In order to avoid the oxidation of activated carbon, it is usually carried out in vacuum or inert atmosphere. In the next activation stage, CO2, CO, H2 or water vapor are injected into the reactor to clean up the micropores of activated carbon and restore its adsorption performance.The activation stage is the key of the whole regeneration process.