The prevention and control of common precursor VOCs pollution will become the key and focus of air pollution control, and the activated carbon adsorption method is a more commonly used method for industrial enterprises to control volatile organic compounds (VOCs).
Requirements for key parameters of activated carbon adsorption method
1. The structure of the activated carbon filter box is reasonably designed, and the unfiltered gas shall not be allowed to enter the subsequent process, and the particulate matter content in the filtered exhaust gas < 1mg/m³. The filter box should have a differential pressure gauge, which should be replaced and recorded in time when the pressure is too large.
2. The ratio of activated carbon filling volume to hourly exhaust gas volume should not be less than 1:5000, and the adsorption cross-sectional area of honeycomb activated carbon per 10,000 Nm³/h should not be less than 2.3 square meters, and the adsorption cross-sectional area of granular activated carbon should not be less than 4.6 square meters.
3. It is best to choose columnar activated carbon with a diameter of ≤5mm, a specific surface area of ≥ 1200 ㎡/g or an iodine value of ≥800mg/g, and the transverse strength of honeycomb activated carbon should not be less than 0.3MPa, the longitudinal strength should not be less than 0.8MPa, and the specific surface area should be ≥750 ㎡/g or iodine value ≥800mg/g.
4. The activated carbon adsorption equipment is equipped with loading and unloading carbon holes, built-in air sharing device, when using granular adsorbent, the gas velocity in the box should be less than 0.6m/s, when using fibrous adsorbent, the gas velocity in the box should be less than 0.15m/s, and when using honeycomb adsorbent, the gas velocity in the box should be less than 1.2m/s.
Activated carbon adsorption facility maintenance
1. If the pretreatment method of water curtain and spray tower is adopted, a water removal device should be set at the front end of the activated carbon to regularly check the water removal capacity.
2. The use time of activated carbon is generally not more than 500 hours (no more than 3 months in normal production).
Exhaust gas collection parameters and minimum activated carbon
Fill volume reference table
Method for identifying the properties of activated carbon
There should be no whitening or discoloration during the life cycle of activated carbon
Activated carbon should not have serious dust accumulation, grease on the surface, moisture, etc
There should be no whitening or discoloration during the life cycle of activated carbon
Serious dust accumulation will lead to the blockage of activated carbon voids, which will seriously affect the adsorption effect.
Processes involving plastic products, investment molding, high-temperature curing, and wax melting will produce tar substances, which are viscous and difficult to pretreat, and the void of the activated carbon adsorption device will be blocked after entering the device, resulting in the reduction of adsorption efficiency.
If the moisture content of the exhaust gas is greater than 50%, the adsorption efficiency of activated carbon will drop sharply, resulting in low treatment efficiency.
The inlet temperature of activated carbon equipment should not be higher than 40 °C, and enterprises should set up activated carbon inlet temperature control sensors to ensure that the adsorption temperature of activated carbon is below 40 °C.
Standardize the operation and maintenance of activated carbon treatment facilities
It not only helps enterprises to meet the emission standards
It helps to reduce production and operation risks
It is important for companies to regularly check the status of activated carbon
Replaced waste activated carbon is hazardous waste
It should be stored tightly closed
It shall be handed over to those with hazardous waste disposal qualifications
The enterprise shall dispose of it in accordance with the law