How to achieve effective treatment of exhaust gas in the coating industry?

Pollution in the chemical industry has always been a headache, and it has been repeatedly banned. According to the modern classification of chemical products, coating belongs to fine chemical products. Modern coatings are gradually becoming a class of multifunctional engineering materials, and they are an important industry in the chemical industry.
At present, my country’s coating industrysolvent-based coatings accounts for 52.1% of the total output, which is much higher than the average 30% of solvent-based coatings in developed countries level. Due to the large amount of organic solvents used in solvent-based coatings, the coating industry has become an important industrial pollution source for the generation and emission of atmospheric VOCs.
Coating industry organic waste gas emissions have the following characteristics: harmful substances are mainly toluene, xylene, butanol, etc. In addition, mixing and grinding processes will also generate a large amount of fine dust and harmful substances The content is low, the VOCs concentration is generally 100～600m∥m3, the dust concentration is 200～680m∥m3, and the flow rate is large, usually 5000～100000m3/ll, which is a typical high-volume, low-concentration waste gas.
In the production process of coatings, coating pollutants have complex composition and high pollutant content. The wastewater contains toxic organics such as phenol and benzene, and some paint wastewater also contains heavy metal ions such as chromium and lead and their compounds, which can be enriched in organisms.
Long-term inhalation by the human body will cause serious damage to health. Exhaust untreated exhaust gas into the atmosphere will also have a certain impact on the surrounding environment. Therefore, the process of energy saving and emission reduction, coating companies We must attach great importance to it. The following is the current way to control paint exhaust gas:
1. Development of new coating materials
Strengthen the guidance of government support funds, and promote the development of green coatings such as water-based coatings, energy-saving coatings, environmental-friendly coatings, special effect coatings, and high-performance coatings. Coatings, multifunctional coatings; focus on adjusting and optimizing the industrial structure to promote energy conservation and emission reduction. We must adhere to a new path of industrialization.
Accelerate the elimination of outdated production capacity, strengthen energy-saving, environmental protection and other indicator constraints, and curb the excessive growth of high-energy, high-emission coating companies. Reduce the ratio of solvent-based coatings and reduce the use of toxic raw materials, vigorously develop environmentally friendly coatings represented by water-based coatings, and reduce the emission of volatile organic compounds. Vigorously develop circular economy.
2. Centralized processing by coating companies
Experts in the industry said that paint coating itself is a composite of chemicals, and the toxic waste gas, waste residue, and waste water generated during the production of paint The pollution caused by the environment cannot be ignored. Relocating the coating company to the chemical park has become the best choice for centralized management of the “three wastes” generated.
3. Configure exhaust gas treatment equipment
There are many types of volatile organic waste gas with different characteristics, so the corresponding treatment technologies are also different. At present, organic waste gas treatment technologies mainly include condensation method, absorption method, regenerative oxidation method, catalytic method, adsorption method and adsorption, catalytic oxidation method, etc., as well as new technology photocatalysis, plasma, etc.
Based on the above analysis and the engineering practice of organic waste gas in the coating industry in recent years, the adsorption-catalytic combustion method has good technical and economic applicability and can adapt to the characteristics of large air volume and low concentration of organic waste gas in the coating industry.
Adsorption-catalytic combustion technology uses activated carbon adsorption hot air desorption, catalytic combustion technology waste heat utilization technical route, namely through desorption concentration to solve the problem of insufficient combustion heat due to low initial concentration, and through the hot air after the catalytic combustion bed purification through the supplement The cold air is used for desorption regeneration of honeycomb activated carbon after cooling to 90℃～120℃, and the waste heat is recovered and used, which reduces the operating cost. In recent years, this technical route has been widely used in the treatment of organic waste gas in the coating industry.
The treatment of dust in the organic waste gas of the coating industry is the key to the success or failure of the treatment project, and it is necessary to choose an appropriate treatment process.