Activization Plant for Activated Carbon Production

Coconut husk, apricot kernel shell, walnut shell, hawthorn kernel
shell, peach kernel shell, coal, palm kernel shell and charcoal are
common raw materials of activated charcoal products available on the
market. Regional resource superiority is dominant in material selection.
The plant is integrated with an automatic control system. Main structure
of the activation furnace consists of a material bin, an elevator, a feeder,
a furnace stack, refractories, a rotator, a temperature detector, an
activator, a cooler, a settling chamber, a boiler, a fan, a deduster, and an
automatic PLC system.

Raw materials are carbonized and screened to eliminate particles
under 2mm. Moisture content shall be controlled at a level below 15%.
Then, materials are filled into the elevator bin, and conveyed to the feeder
on top. From the feeder bin, materials are fed into the furnace evenly by a
variable-frequency feeder, and heated by an ignitor. Temperature inside
the furnace shall be above 800°C before feeding. A calculated amount
of oxygen and vapor is delivered into the furnace through the fan for
activation. 4 tons of vapor are required for one ton of finished activated
carbon products, and penetrating vapor shall be used instead of spreading
vapor for restraining ignition loss and improving efficiency. Materials are
conveyed into the pre-heating section following rotating movement of
the furnace, and then into the activation section after their temperature
reaches 800°C. Temperature of the material will climb dramatically to
900-1050°C after contact with vapor. Duration of the contact between
material and vapor is known as Activation Time, which is variable within
the range of 30-40 minutes, given the specific temperature and oxygen
amount. To meet the duration required, materials in the furnace shall
be moved forward at a rate of 6m/h. Temperature of materials shall be
500-600°C in the discharge tube of cooling section, and around 200°C as
they leave the tube for a water-cooling device separated with the furnace,
where the activated materials shall be cooled to a room temperature
between 30-40°C after approximately 3 minutes of anaerobic cooling
before they slide into prepared jumbo bags (0.5 ton of capacity each)
out of gravity, or convey to the next bin for grinding via the pneumatic
conveyor. Filled jumbo bags may be moved by manual forklifts. The
settling chamber in the end of the furnace is designed for 4 purposes,
which are preheating the waste heat boiler, dust settling, keeping vapor
infusion to avoid frozen pipelines in cold regions, and combusting
incomplete combusted fume to reduce black smoke and efficiently use
energy generated by fume combustion. The waste heat boiler connected
to the settling chamber is designed for generating vapor for activating
material by high-temperature (around 800°C) end gas. The induced draft
fan connected to the boiler is designed for pumping the high-temperature
end gas into the waste heat boiler, and then into the pouch- style pulse
dust collector for subsequent end-gas treatment, such as sprinkling, to
meet emission standard. Output of the plant varies with specific material
type and quality requirements. Desulfurization and denitrification devices
are required for coal carbon production. See the table below for outputs.

The entire process is controlled by a PLC system which offers
much lower labor intensity, controllable quality, safety, much less manual
work, comparing to traditional operation mode. Moreover, the plant is
capable of prolonged continuous operation without blowing out, thanks
for a maintenance ratio significantly lower than that of products of other
manufacturers'.