Product Description

Hazardous Waste Activated Carbon Regeneration Plant
 
Saturated activated carbons with no more capability of absorption are wastes
which have been specified as Hazardous Wastes by the national environmental
conservation authority, and must be recycled by competent recycling companies
for reuse to reduce secondary purchase cost of related business.
 
The company currently manufactures furnace with a diameter of 1 .9m,
2.2m, 2.4m or 2.6m, and a length between *2m to *7m. The plant is completely
controlled by PLC negative-pressure system which offers higher efficiency, safety
and more controllable quality comparing to the old-fashioned controlling method.
1t mainly consists of a lifter, a material bin, an activation furnace stack, a feeder,
an actuator, refractories, an activator, a waste heat boiler, a pressure sensor, a
fan, a cooling discharger, a dust collector, a waste gas recycler, a PLC cabinet, an
auxiliary preheater, an end-gas dryer for pretreatment, a drying furnace stack, an
air- tight conveyor, an end-gas combustor, a waste heat recycler, a quencher, a
desulfurizer, a denitrator, a dioxin separator, and a deduster.
 
I. Waste carbons shall be collected in jumbo bags, and regenerated when a
certain quantity is reached. For regeneration, waste carbons are filled into the lifter
bin (approx. 6m3), lifted into preheating bin (waste heat furnace and combustion
furnace shall be heated before starting rotary furnace), and fed into furnace by
the variable-frequency feeder for drying with heat from waste gas in lifter blade.
Dried materials are conveyed forward in the regeneration furnace for preheating
gradually till desorption temperature (******0°C) is reached. Temperature and
vapor control at this point is critical for the quality of regeneration. The proper
temperature shall be *******0°C during the ****5 minutes of activation period
with a vapor consumption of **3 ton/hour.
 
II. Proper vapor supply and pressure are keys to secure an effective activation,
and prevent a temperature drop. Vapor supply shall be started gradually  when
temperature in the furnace reaches a constant level, meanwhile, heat supplied by
preheater  shall be limited to facilitate generation of water gas through combination
reactions of vapor and carbon. An appropriate amount of oxygen is required for
the penetrating activation by vapor to achieve the optimal result. Materials are
discharged and cooled down to ******0°C through the rotary cooling tube of the
rotary furnace, and then conveyed into the cooling furnace again following rotation
of the furnace stack. Regenerated activated carbons are obtained after 3 minutes of
water cooling at an anaerobic state in furnace, and collected into material bin
through air-tight gas flow conveyor. At this point, materials and oxygen are flowing
to opposite directions in the furnace, which is known as the reverse flow method,
being different from the forward flow method in which materials and oxygen
supply flow in the same direction (the latter is applicable for producing brand-new
activated carbon only). The heater mentioned below refers to auxiliary heating
by natural gas or combustor for reaching the temperature required for activation
when volatiles from materials are insufficient. When end gas of *******0°C is
induced into secondary combustion furnace by the feeding fan, and the end gas of
*********0°C from high-temperature combustion is induced into waste heat boiler
again, the waste gas of *******0°C at this point is induced into pouch*-style pulse
deduster by the fan on waste heat boiler through jet ammonium hydroxide pump,
alkaline liquor spray tower, gas*-water separator (condenser), quicklime jet tower,
active carbon jet tower, cyclone collector and secondary alkaline liquor spray in
sequence, and then conveyed into the active carbon absorption tank for waste gas
collection before discharging to an elevation of *5 meters. The above regeneration
cycle takes about 2 hours, and subject to negative*-pressure sensory control.
 
III. Particularity of material. Waste carbons may had absorbed all kinds
of organic or inorganic substances, quantity and components of waste gas
generated therefore would never be constant. The complicity has been duly
considered by designers of the plant. Output is determined by moisture content
and absorbed volatile content. When moisture content of material is dried to
a level below 1 5%，capacity is ****0 ton (raw material), and quantity of fume
mixture is *0,*****5 ,**0/hour. Therefore, auxiliary device for end gas treatment
is required. All devices used in the process are resistant to high-temperature
and corrosion.
 
IV. According to requirements of environmental impact assessment,
negative-pressure venting systems shall be used for material storage, gas shall
be delivered into combustion furnace, and end gas from material drying shall be
combusted in combustion furnace.
Note: size of furnace stack, boiler, combustion furnace, tubes and fans shall
match specific output of regenerated products.