Automobile Paint Room Exhaust Gas Treatment Method

The harmful gases in the paint processing of automobile paint booths are mainly organic substances such as benzene series and non-methane total hydrocarbons. The chemical composition is complex, and the raw materials of the products are different, the composition and concentration are different, and the treatment methods are various and different in characteristics. Commonly used are adsorption water spray method, condensation recovery method, absorption method, combustion method, catalytic method, etc.

Adsorption method: (1) Direct adsorption method: organic gas directly passes through activated carbon granules or activated carbon filter cotton, which can achieve a purification rate of 95%. The equipment is simple, the investment is small, and the operation is convenient, but the activated carbon needs to be replaced frequently for low concentration and pollution. When the material does not need to be recycled. (2) Adsorption recovery method: the organic gas is adsorbed by activated carbon, and the activated carbon is saturated and then desorbed and regenerated with hot air.

Water spray method: The water spray process has a wide range of applications in air pollution treatment and is also used in the spraying process. For example, the water curtain cabinet is an example. The principle is to spray water to exhaust gas to make the water soluble in the exhaust gas or The large particle components settle down to achieve the purpose of separating the pollutants from the clean gas. The advantage is that the water resources are easily available, and can be reused after filtration and precipitation to minimize the waste of water resources. The water spray is used to treat large particle components. It has a very high efficiency and is often used as a pretreatment for waste gas treatment.

Condensation recovery method: The exhaust gas is directly condensed or adsorbed and concentrated, and then condensed. The condensate is separated and recovered with valuable organic matter. The method is applied to exhaust gas with high concentration, low temperature and small air volume. However, this method has large investment and high energy consumption. The operating cost is large, so there is no special need, and this method is generally not used.

Absorption method: It can be divided into chemical absorption and physical absorption, but "triphenyl" waste gas has low chemical activity and generally does not use chemical absorption. Physical absorption is the use of liquid absorbent with less volatility, which has High affinity, absorption saturation, re-use after heating and analysis. This method is used for exhaust gas with low atmospheric temperature, low temperature and low concentration. The device is complex and the investment is large. The selection of absorption liquid is difficult and there is secondary pollution.

Direct combustion method: use the heat released by the auxiliary fuel such as gas or fuel to heat the mixed gas to a certain temperature (700-800 ° C), and stay for a certain period of time to burn the combustible harmful gas. The process is simple and the equipment investment is low. , but high energy consumption and high operating costs.

Catalytic combustion method: the exhaust gas is heated to 200~300 °C and burned through the catalytic bed to achieve the purpose of purification. The method has low energy consumption, high purification rate, no secondary pollution, simple process and convenient operation. It is suitable for high temperature and high concentration organic waste gas treatment. It is not suitable for the treatment of organic waste gas with low concentration and high air volume.