Common Treatment Methods The main pollutants produced by spray painting are organic solvents and organic gases generated by the volatilization of thinners. Common methods for handling such organisms are:
1. Direct combustion method: using oil or natural gas as an auxiliary fuel to burn and heat the mixture to a certain temperature (700°C-800 °C), the use of heating and high temperature methods, the direct treatment of organic waste gas to achieve the purpose of exhaust gas purification;
The method is simple in technology, low in equipment investment, but high in energy consumption and high in running cost.
2. Water spray method: Spray paint exhaust water treatment water spray technology is widely used in air pollution control, and has been applied in the spraying process. For example, the water curtain cabinet is used as an example. The principle is to spray water in the exhaust, water-soluble or large particles. Settlement to achieve the purpose of separation of pollutants. After sedimentation and filtration at the same time, the water can be reused to reduce the waste of water resources. The water spray has a very high efficiency in the treatment of large particles and is usually used in the pretreatment of exhaust gas treatment.
3. Activated Carbon Adsorption: Activated carbon is used as an adsorbent because of its large adsorption surface area and strong adsorption capacity. When exhaust gas passes through an adsorbent, harmful substances in the exhaust gas are adsorbed and the exhaust gas is purified; the organic gas is directly adsorbed, and the equipment It is simple, small in investment and convenient in operation, but it requires frequent replacement of activated carbon and subsequent treatment of activated carbon that is replaced after use.
4. Photo-Oxygen Catalytic Degradation: The mercury lines in the UV tube are excited to produce characteristic lines of mercury, and ozone is generated by ionized air. Ozone is a strong oxidant, which has the functions of sterilization and deodorization; meanwhile, when photo-oxygen catalysis, Its nano-wavelength light energy can effectively cut, break chain, burn, crack the molecular chain of exhaust gas, change the molecular structure of exhaust gas, and then through strong oxidization, combine the destroyed exhaust gas molecules or atoms with O3, organic or inorganic polymer The odorous compound molecular chains are converted into low-molecular compounds such as C02, H2O, etc. during the catalytic oxidation process. UV photo-catalysis can be regarded as a kind of cold combustion. The catalyst uses a honeycomb metal mesh as a carrier, catalyzes the reaction under full-scale contact with a light source, and amplifies the effect of a light source of 10-30 times, making it fully react with the exhaust gas. Shorten the contact time between the exhaust gas and the light source, thereby improving the efficiency of exhaust gas purification and deodorization.
5. Plasma reaction method: The exhaust gas molecules are decomposed using a plasma containing a high-energy reactive group to generate carbon dioxide and water, thereby achieving the purpose of purifying the exhaust gas. However, this method is not suitable for use in the treatment of flammable and explosive paint organic exhaust gas. It has potential safety hazards and the maintenance of the equipment is complicated.
(6) Condensation method: Spray paint treatment Direct condensation or adsorption Concentration condensation After recovery, the condensate is recovered by separating organics of value. This method is used for high concentration, low temperature, and small volume of exhaust gas treatment. However, large investment, high energy consumption, high operating costs. This method is generally not used to purify paint exhaust gas.
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