Activated carbon is currently one of the indispensable purification and adsorption products in the industrial and civil fields. Its products can effectively adsorb impurities and toxic substances in air and liquids. After adsorption saturation, the activated carbon can be recycled after deep processing, and the adsorption performance remains unchanged. The raw materials for producing activated carbon are common types of fruit shells (such as coconut shells, apricot shells, walnut shells, etc.), coal types such as anthracite and clean coal, and wood types are various logs. The following is Yanhe’s introduction to the basic equipment needed in the production of activated carbon.
1. Carbonization furnace, the appearance is a cylinder installed vertically on the ground, with a feed port and a discharge port.
2. Heating furnace, which is connected to the carbonization furnace through this furnace to get heating from the outside.
3. Liquefaction furnace, the gas in the liquefaction furnace comes from the gas discharged from the carbonization equipment, and is liquefied this time.
4. Activation furnace, the appearance is similar to the carbonization furnace, and the difference from the carbonization furnace is that it can heat the activated carbon to a higher temperature.
5. Mixer: The activated carbon is rotated and stirred at a specified speed by the stirring equipment, so that the activated carbon can be heated evenly during the carbonization and activation process.
Activated carbon carbonization process conditions: 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; 12℃/min for particles less than 3mm. 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 the material under low temperature (below 600℃). As the molding materials move from the low temperature of entering the carbonization furnace to the high temperature of 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 material finally meets the specified requirements when it leaves the furnace.
The activated carbon activation process is the most critical process in the production of activated carbon, 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 activated carbon pore structure. 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 the activated carbon is prone to change, the micropores will decrease, the macropores will increase, the strength will decrease, and the yield will decrease. 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. Table 7 shows the effect of activation temperature on the adsorption performance of activated carbon. In order to maintain the normal activation reaction temperature, secondary air must be added to different positions of the heating half of the activation furnace, and the combustion of the combustible gas in the mixed gas releases a large amount of heat. The main reactions are as follows: Since the heat released is sufficient to keep the activation reaction in a state of thermal equilibrium, the two halves of the furnace are operated alternately at regular intervals to stabilize the activation temperature, achieve good activation effect, and ensure uniform product quality and strong adsorption capacity.
