What are the methods of water-based paint exhaust treatment

Water-based paint in the manufacturing, construction, drying process to the air to release a large number of volatile organic compounds (VOC), is one of the main causes of acid fog, smog, ozone, the need for timely exhaust treatment, otherwise not only on human health hazards and threats, but also on the air pollution generated by the serious pollution, the following with the Everest blue editorial to see the exhaust treatment of waterborne paint what are the methods?

Water-based paint exhaust gas treatment methods are common mainly activated carbon adsorption methods, ion purification methods, combustion methods and so on.

Activated carbon adsorption method

The main principle of activated carbon adsorption method is to use porous solid adsorbent (activated carbon, silica gel, molecular sieve, etc.) to deal with organic waste gas, so that through the chemical bonding force or molecular gravity to fully adsorb the harmful components and adsorption on the surface of the adsorbent, so as to achieve the purpose of purification of organic waste gas. The adsorption method is mainly applied to the purification of organic waste gas with large air volume, low concentration (≤800mg/m3), no particles, no viscous matter, and low concentration of organic waste gas at room temperature.

Activated carbon purification rate is high (activated carbon adsorption can reach more than 95%), practical and widespread, simple operation, low investment. In the adsorption of saturation after the need to replace the new activated carbon, replacement of activated carbon needs to spend, replace the saturated activated carbon after the need to find professional staff to carry out hazardous waste treatment, the operation of the high cost.

Ion purification method

Ion purification method makes use of the characteristics of the ionomer internal generation rich in high chemical activity, the use of high-voltage discharge device in the discharge of high-energy electrons and ions, the separation of oxygen molecules in the air, oxygen molecules absorb the energy to produce the free state of the oxygen ions, organic waste gas pollutants and the reaction of the free oxygen group, the ultimate conversion into CO2 and H2O and other substances, so as to achieve the purpose of purifying waste gas.

This method has a wide range of application, high purification efficiency, small equipment footprint characteristics, suitable for other methods more difficult to deal with organic waste gas; but because of the use of high-voltage discharge device, in the water, dust, organic waste gas concentration of high concentration in the confined space is prone to explosion, there is a security risk, thus limiting the use of it.

Combustion method

The combustion method is only used when volatile organic compounds are completely burned under the premise of high temperature and sufficient air, and decomposed into CO2 and H2O. The combustion method is used for all kinds of organic waste gas, and can be divided into direct combustion method, thermal combustion method and catalytic combustion method.

Emission concentration greater than 5000mg/m3 of high concentration of waste gas is generally used in direct combustion method, the method will be VOCs exhaust gas as a fuel for combustion, combustion temperature is generally controlled at 1100 ℃, the processing efficiency is high, can reach 95% 99%.

Thermal combustion method is suitable for the treatment of exhaust gas concentration of 1000-5000 mg/m3, the use of thermal combustion method, the concentration of VOCs in the exhaust gas is lower, with the help of other fuels or combustion gases, thermal combustion requires a lower temperature than the direct combustion, about 540-820 ℃. The combustion method is highly efficient in treating VOCs exhaust gas, but if the VOCs exhaust gas contains elements such as S, N, etc., the exhaust gas generated after combustion is directly discharged, which will lead to secondary pollution.

Through the thermal combustion method or catalytic combustion method to deal with organic waste gas, its purification rate is relatively high, but its investment and operation costs are extremely high. It is difficult to achieve centralised collection because of the many and scattered points of exhaust gas emission. The combustion device needs many sets and requires a large area. Thermal combustion is more suitable for 24-hour continuous operation and higher concentration of waste gas conditions without chaos, not suitable for intermittent production line conditions. Catalytic combustion investment and operating costs are relatively low compared to thermal combustion, but the purification efficiency is also relatively low; but the precious metal catalyst is easily due to impurities in the exhaust gas (such as sulphide) and so on caused by poisoning failure, and replacement of the catalyst is very high; at the same time on the exhaust gas inlet prerequisites for the control of a very strict, otherwise it will result in the catalytic combustion chamber clogging and cause safety accidents.