The production process of nut shell activated carbon is an efficient adsorption material made from coconut shell, walnut shell, apricot shell and other fruit shells through carbonization, activation and other core processes. The complete process and technical points are as follows:
I. Screening and pretreatment of raw materials
Raw material selection: high carbon content (such as coconut shell carbon content ≥70%), high porosity (such as walnut shell porosity of 0.8~1.2cm³/g), to ensure that the activated specific surface area of 800~1500㎡/g. Common raw materials include coconut shell, peach shell, apricot shell, jujube shell.
Preprocessing process:
Cleaning: remove sediment and impurities, two-stage countercurrent cleaning control ash ≤5% (for every 1% reduction in ash, activation energy consumption is reduced by 8%).
Crushing: Crushing to particle size 3~10mm, improve carbonation uniformity .
Drying: 80-105 ℃ air flow drying, final moisture ≤5%, to avoid subsequent process temperature fluctuations.
2.The core production process
Carbonization (anoxic pyrolysis)
When heated at 400 to 600 ° C in a hypoxic environment, volatiles escape and form a primary carbon structure (carbonizing material) .
Continuous treatment of carbonization furnaces improves efficiency and reduces losses.
Activation (critical for pore generation)
Physical activation:
Water vapor or carbon dioxide at 800 to 1000 ° C is introduced to ablate the carbon layer to form micropores (pore size 2 to 50nm).
The specific surface area can reach 500~1500㎡/g, suitable for food grade applications.
Chemical Activation Method:
Phosphoric acid, zinc chloride and other reagents soak (solid-liquid ratio 1:3), and then heat corrosion to create pores, the iodine value increased by 15 to 20%.
Subsequent cleaning is required to remove chemical residues.
3.Post-processing and quality control
Purification treatment:
Acid/water washing to remove activation residues, chemical methods need to be thoroughly cleaned.
Rinse and dry in hot air with moisture ≤5%.
Grading and Packaging :
Sieved pellets (e.g. 8-30 mesh), sealed and moistureproof packaging according to specifications .
Quality Inspection standard :
Key indicators: iodine value (adsorption capacity), specific surface area, wear resistance .
High quality fruit shell activated carbon iodine value ≥1000mg/g, ash ≤5%.
4. Product advantages and application fields
Performance Features:
High adsorption capacity, good mechanical strength (wear resistance), strong regeneration capacity.
Natural raw materials are more environmentally friendly and cost 40%316 less than coal-based activated carbon.
Main Application scenarios:
Water treatment: drinking water purification (removal of residual chlorine, heavy metals), industrial wastewater decolorization and dephenolization .
Gas purification: VOCs adsorption, flue gas desulfurization, air deodorization (household/industrial) .
Other fields: Food decolorization, pharmaceutical purification, catalyst support
5. Process optimization direction
Raw material efficiency: phosphoric acid modification increases iodine value, although the cost increases by 0.15 yuan /kg, but the price can increase by 0.8 yuan /kg.
Energy saving: Control ash and moisture content, reduce activation energy consumption .
Equipment maintenance: the 10,000-ton production line needs to pay attention to the maintenance of crushing and screening equipment (annual maintenance fee is about USD 1600) .
The nut shell activated carbon process can accurately control the carbonation temperature, activation medium and post-treatment, balance the adsorption performance and economy, and become the optimal scheme of environmentally friendly adsorption materials.
