The copper smelting process generates dust – gases released into the environment, exhaust gas streams withhigh temperature,metal dust, gases including CO2, SO2, CO, NOx, fluorine compound gas,…. If these issues are not thoroughly handled, they will cause serious impacts on the environment and especially human health.
Dust flow characteristics
Dust has a relatively high temperature, about 500 – 700ºC.
Due to cooking at high temperatures, the smoke and dust are also mixed with some copper oxide dust.
In addition, dust also contains a small part of CO, NO2,SO2 and metals such as Mg, Pb, Si…, due to combustion reactionformation and input copper material composition. The copper smelting exhaust gas composition parameters are shown in the table below.
Concentration table of components in dust and smoke generated in copper furnaces
Through the data table given, it can be easily seen that the concentrations of emissions in the dust cooking exhaust gas component all exceed QCVN 19:2009/BTNMT: National technical regulation on industrial emissions for dust and substances. Inorganic.
With the above emissions, it will have a very serious direct impact onthe people working and operating in the factory, factory and will affect everyone around the production area at the same time. to the surrounding ecosystem.
Therefore, it is necessary to build a copper cooking exhaust gas treatment system before releasing it into the environment.
After studying the characteristics and properties of the copper smelting exhaust source, the following technological principles for treating copper smelting exhaust gas are proposed as follows:
To thoroughly treat pollutants in copper cooking exhaust gas, combined technology is applied. Compared with other methods, the absorption buffer tower has the following outstanding advantages:
The device is compact, lightweight, and easy to manufacture.
High processing efficiency.
Simple operation and maintenance.
Low operating costs.
General introduction to buffer towers in copper smelting waste gas treatment
The absorption mattress tower consists of a hollow tower body filled with mattresses made from different materials (plastic wood, metal, gum, etc.) with different shapes (pillars, bridges, plates, saddles, springs, etc.) , mattress support mesh, air and liquid inlet and outlet pipes.
Image of exhaust gas absorption buffer tower
To evenly distribute the liquid onto the buffer block contained in the tower, people use a distributor in the form of: distribution grid (liquid goes in the tube – gas outside the tube; liquid and gas in the same tube); distribution membrane, shower nozzle (cylindrical, hemispherical, slit…); rotating wheel (tube with hole, rotating spray, bearing…)
The spacer elements are characterized by diameter d, height h, thickness δ. The spacer block is characterized by the following dimensions: specific surface a, free volume, equivalent diameter, free cross-section S.
When choosing a mattress, keep in mind: good liquid absorption; small resistance, large free volume and cross-section; Can work with large loads of liquid and gas, small density; evenly distributes the liquid; has high corrosion resistance; cheap; easy to find…
Principle of operation
The liquid flows in the tower along the buffer in the form of a trough, so the phase contact surface is the wetting surface of the buffer.
Advantages and disadvantages
Advantages: simple structure; Gas-phase resistance (operating in membrane/transient mode) is small.
Disadvantages: less stable operation, low performance; easy to choke; difficult to separate heat, difficult to wet.
Used in cases of low productivity: gas absorption tower, distillation tower,…
Used in small resistance systems (such as vacuum systems,…)
Explanation of exhaust gas flow
Exhaust gases generated in the copper smelting furnace and related processes will be thoroughly recovered by dust extraction hoods. Dust is guided through pipes to a buffer absorption tower.
Here the exhaust gas is cooled, the pollution parameters are retained in the absorption solution and absorption buffer, and follow the water flow out. The gas leaving the top of the tower is sucked into the chimney by a fan and discharged into the environment.
The released gas meets column B of QCVN 19: 2009/BTNMT on industrial emissions for dust and inorganic substances, applicable to factories and facilities in operation.
Some features to note when designing the system
Design opening and closing valves at branches to optimize the smoke extraction process. Dust when cooking copper as well as when maintenance is needed.
The operating capacity of the system is adjusted up or down corresponding to the operating capacity of the system tominimize operating costs.
Treating dust from copper smelting exhaust
Image of dust treatment of the Cyclon copper cooking process
The exhaust gas stream is collected by the exhaust fan and sent to the Cyclon dust separator. Dust follows the duct into the door to the area near the top of the device.
Then, the airflow containing dust enters the body of the Cyclon in a tangential direction to the body of the Cyclon. At the top, then spiral down and gradually meet the funnel-shaped tube. The exhaust fan helps dust move in a spiral direction.
Dust, under the effect of centrifugal force, is thrown into the Cyclon wall. The dust gradually lost its velocity and fell to the bottom of the Cyclon. The air flow after dust is removed follows the pipeline. Go up to the absorption tower to treat gas components in the gas stream after separating dust.
Treatment of gases in copper cooking exhaust gas
Image of model of copper smelting exhaust gas treatment technology
Exhaust gas goes from the bottom to the top of the tower, water containing the absorbent NaOH is pumped and evenly distributed to the surface of the buffer layer divided into two floors in the treatment tower, absorbing toxic substances in the exhaust gas. The copper cooking waste gas treatment process goes through 4 stages
Stages of copper smelting waste gas treatment
Dust containing copper, copper compounds and a number of other toxic substances generated during copper smelting and related processes will be recovered by dust collection hoods.
Gas carrying dust and smoke from the suction hoods will be collected into the cushion-type absorption tower thanks to the exhaust fan placed behind the tower to avoid high-temperature air flow damaging the exhaust fan.
Here, gas is brought in from the bottom of the tower. The absorbent solution is sprayedfrom top to bottom. The exhaust gas comes into contact with the absorption solution, and the absorption pad in the tower. The substance to be treated is retained, and the exhaust gas temperature is reduced.
The absorption solution containing waste is collected through the drain at the bottom of the tower, the clean gas reaches column B of QCVN 19: 2009/BTNMT on industrial emissions of dust and inorganic substances, exiting the chimney into the environment. .
Thus, the smelting of alloys in general and copper in particular releases many toxic substances into the environment with concentrations exceeding the allowable threshold.
Therefore, it is necessary toapply and build an exhaust gas treatment system to ensure that the concentration of pollutants reach the threshold permit, avoid affecting the surrounding environment and human health.
If you are interested and want to learn more about exhaust gas treatment, please contact us immediately at 0972221608 or website https://xulymoitruong360.com/ HASY ENVIRONMENT is ready to advise and answer.
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