Activated carbon kiln is a special equipment for producing activated carbon. It converts carbon-containing raw materials (such as wood, coconut shells, coal, etc.) into activated carbon with high adsorption performance through high-temperature pyrolysis and activation processes. The following is a detailed introduction to activated carbon kilns:
1. Types of activated carbon kilns
According to different processes and structures, activated carbon kilns are mainly divided into the following categories:
Slot Furnace
Using gas activation method (such as water vapor or carbon dioxide) to activate raw materials through high temperature (800-1000℃).
Divided into multiple heating zones, suitable for continuous production, low energy consumption.
Rotary Kiln
The raw materials are heated evenly through rotation, suitable for large-scale production, and can handle granular or powdered raw materials.
Commonly used for physical activation (introducing activation gas after high-temperature carbonization).
Vertical Furnace
Compact structure, suitable for small-scale or intermittent production, commonly used chemical activation method (such as phosphoric acid, zinc chloride, etc.).
Fluidized Bed Furnace
The raw materials are suspended in the air flow, and the activation efficiency is high, but the equipment is complex and suitable for high value-added products.
2. Production process
Raw material pretreatment
Raw materials are crushed and screened to the appropriate size (such as coconut shells need to be crushed to 3-10mm).
Carbonization
Heating (400-600℃) in an oxygen-deficient environment removes volatiles to form primary carbon.
Activation
Physical activation: water vapor/carbon dioxide is introduced, and part of the carbon is oxidized at high temperature (800-1000℃) to form a porous structure.
Chemical activation: impregnation with chemical reagents (such as phosphoric acid), heating to a lower temperature (400-700℃) for direct activation.
Cooling and post-processing
After cooling, the activated carbon is acid-washed, washed with water, dried, and screened to obtain the finished product.
3. Key parameter control
Temperature: The temperature in the activation stage directly affects the pore development (too high will destroy the structure, and too low will result in insufficient activation).
Activator flow rate: The flow rate of water vapor or gas needs to be precisely controlled to ensure uniform activation.
Time: Carbonization and activation time affect the yield and adsorption performance (usually activation time is 1-3 hours).
4. Application areas
Activated carbon products are widely used in:
Environmental protection: wastewater treatment, waste gas purification (VOCs adsorption).
Food industry: decolorization, deodorization (such as sugar refining).
Medicine: drug purification, poison adsorption.
Energy: supercapacitors, energy storage materials.
5. Environmental protection and energy saving considerations
Tail gas treatment: The waste gas generated during the activation process needs to be burned or washed to avoid pollution.
Waste heat recovery: Use the waste heat of flue gas to preheat the raw materials or dry them to reduce energy consumption.
Raw material sustainability: Give priority to renewable resources such as coconut shells and wood.
6. Common problems and solutions
Uneven activation: Optimize airflow distribution or adjust the particle size of the raw materials.
Low yield: Check whether the carbonization temperature is too high or the activation gas is excessive.
Poor mechanical strength: may be caused by improper raw material selection or excessive activation.
