Carbonization should be heated and distilled under the condition of air isolation, but in actual production, due to the negative pressure in the carbonization furnace, the production system cannot be absolutely strict, which leads to the need for some air to be brought into the carbonization system, causing the combustion of the carbonized material in the furnace, and even the extraction of materials to block the equipment pipeline. According to experience, the negative pressure in the carbonization furnace should be controlled between 30~100Pa. The most important factors in the carbonization process are the final carbonization temperature and the carbonization heating rate. In the actual production process, the carbonization heating rate is generally 8℃/min for coarse particles with a particle size of 5.0~7.0mm; 10℃/min for medium materials with a particle size of 3.0~5.0mm; and 12℃/min for particles less than 3.0mm. Carbonization is one of the important processes in the production of activated carbon. The quality of carbonization directly affects the next step of activation and the quality of the final product. Carbonization of molding materials refers to the process of volatilization of low molecular weight substances in coal tar and thermal decomposition and solidification of coal and asphalt in materials under low temperature (below 600℃). As the molding materials move from low temperature when entering the carbonization furnace to high temperature when leaving the furnace, in addition to making the particles shorter and more uniform, more importantly, the volatile matter in the strip material is continuously released from the carbon particles as the temperature continues to rise, and the carbonized materials finally meet the specified requirements when they leave the furnace.
The activated carbon activation process is the most critical process in the activated carbon production process, which directly affects the performance, cost and quality of activated carbon products. Activation is carried out by an activation furnace, which is a furnace type that uses water vapor and flue gas as activators. Activation temperature is one of the main factors that determine the speed of formation of the pore structure of activated carbon. The main activation reaction is a reversible endothermic reaction. According to the law of thermodynamic reaction, increasing the reaction temperature is conducive to the positive reaction, which can increase the activation reaction rate. However, if the temperature is too high, the pore structure of activated carbon is prone to change, the micropores are reduced, the macropores are increased, the strength is reduced, and the yield is reduced. However, columnar activated carbon for water treatment has strict requirements on strength. Therefore, the selection of activation temperature should take into account the relationship between adsorption capacity and strength.
