20

2017

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05

Spraying VOCs waste gas and treatment methods, responding to the key points of the inspector (VI)

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Organic waste gas treatment in automobile manufacturing industry VOCs and other waste gas produced in the coating process of automobile manufacturing process need to be controlled in the field to prevent it from spreading into the atmosphere and causing further pollution. Usually, the exhaust gas generated in the automobile coating process can be treated by the following methods. Activated carbon adsorption method This method is the use of activated carbon as a physical adsorbent, the use of its capillary condensation and intermolecular gravity, the harmful substances adsorbed on the surface of activated carbon, so that the exhaust gas purification. The advantages of this method are: the solvent can be recovered, the low concentration, low temperature exhaust gas can be purified, without heating. Disadvantages are: the need for pretreatment to remove paint mist,

Organic waste gas treatment in automobile manufacturing industry

Exhaust gases such as VOCs produced in the coating process of automobile manufacturing need to be controlled in the field to prevent them from diffusing into the atmosphere and causing further pollution. Usually, the exhaust gas generated in the automobile coating process can be treated by the following methods.

activated carbon adsorption method

This method isUsing activated carbon as a physical adsorbent, Using its capillary condensation and intermolecular attraction,Adsorption of harmful substances on the surface of activated carbonThe exhaust gas is purified. The advantages of this method are: the solvent can be recovered, the low concentration, low temperature exhaust gas can be purified, without heating. Disadvantages are: the need for pretreatment to remove paint mist, dust, smoke, oil and other impurities, high temperature exhaust gas needs to be cooled.

catalyst combustion method

This method isThe gas containing organic solvent is heated to 200~400 ℃, at this time the gas through the catalyst layer, oxidation reaction, So that it can burn at a lower temperature and consume less heat energy. The advantages are: small device, low fuel cost, less NOx production. The disadvantages are: good pretreatment is required, and the catalyst and equipment are more expensive.

direct combustion method

The direct combustion method isThe gas containing the organic solvent is heated to 600 to 800 ° C. and is directly combusted to cause an oxidation reaction to decompose into carbon dioxide and water.The advantages are: simple operation, easy maintenance, no pretreatment, organic matter can be completely burned, which is conducive to the purification of high-concentration exhaust gas; combustion heat can be used as a heat source in the drying room for comprehensive utilization. The disadvantage is that when NOx exhaust increases, the combustion costs are greater when treated alone.

Environmental protection coating method

Use low VOC or no VOC environmentally friendly coatings (high solids coatings, water-based coatings, powder coatings, etc.) instead of organic solvent-based coatings.This method can more thoroughly solve the VOC (volatile organic compounds) pollution to the atmosphere, can be said to be a permanent measure. Low VOC or no VOC environmentally friendly coatings in the coating is not simply to reduce the amount of organic solvents, but to maintain the construction performance (such as construction viscosity) basically unchanged, redesign or adjust the formula, the use of new resin coatings, the use of water-based coatings and powder coatings to replace solvent-based coatings, so as to achieve the effect of reducing VOC.

improving efficiency method

Improve the coating efficiency, especially to improve the coating efficiency of spraying operations. The specific methods are as follows: ① realize low-voltage and electrostatic spraying by manual air spraying (replace the general air spraying gun with air electrostatic spraying gun); ② overcome human factors, such as the proficiency, responsibility and physical condition of the operators, and adopt automatic electrostatic spraying instead of manual spraying; ③ adopt robot automatic cup electrostatic spraying instead of reciprocating automatic cup electrostatic spraying, as well as rationalization of spraying conditions and intelligent control measures to reduce over-spraying and improve coating efficiency.