company news about Spray painting room tribenzene waste gas treatment technical scheme

(1) Process comparison and selection
There are many kinds of organic waste gas treatment methods with different characteristics, commonly used water spray method, condensation method, absorption method, combustion method, catalytic method, adsorption method and so on.
1, water spray method: water spray process in the air pollution treatment has a wide range of applications, in the spraying process has also been used, such as water curtain cabinet is an example, the principle is by spraying the water exhaust gas, the water-soluble or large particle components in the exhaust gas settlement down, to achieve the purpose of separating pollutants and clean gases. Its advantage is that water resources are easy to obtain, and can be reused after filtration and precipitation, reducing the waste of water resources. Water spray has a high efficiency in the treatment of large particle components, and is often used as a pre-treatment of waste gas treatment.
2. Condensation recovery method: the waste gas is directly condensed or condensed by adsorption, and the condensate is separated to recover valuable organic matter. This method is used for waste gas treatment with high concentration, low temperature and small air volume. However, this method has large investment, high energy consumption and large operating costs, so there is no special need, and this method is generally not used.
3. Absorption method: It can be divided into chemical absorption and physical absorption, but the chemical activity of "tribenzene" waste gas is low, and chemical absorption is generally not used. Physical absorption is the selection of a liquid absorber with small volatility, which has a high affinity with the absorbed components, and is re-used after absorption saturation by heating, analysis and cooling. The method is used for exhaust gas with large volume, low temperature and low concentration. The device is complicated, the investment is large, the selection of the absorption solution is difficult, and there is secondary pollution.
4. Direct combustion method: The use of gas or fuel and other auxiliary fuel combustion of the heat released by heating the mixed gas to a certain temperature (700-800 ° C), dwell for a certain time, so that flammable harmful gas combustion. The process is simple, the equipment investment is small, but the energy consumption is large and the operation cost is high.
5. Catalytic combustion method: the exhaust gas is heated to 200 ~ 300℃ and burned in the catalytic bed to achieve the purpose of purification. The method has the advantages of low energy consumption, high purification rate, no secondary pollution, simple process and convenient operation. It is suitable for the treatment of high temperature and high concentration organic waste gas, not for the treatment of low concentration and large air volume organic waste gas.
6. Adsorption method: (1) Direct adsorption method: organic gas directly through activated carbon, can reach 95% purification rate, simple equipment, small investment, easy operation, but the need to often replace the activated carbon, for low concentration, pollutants do not need to recover the occasion. (2) Adsorption recovery method: organic gas is adsorbed by activated carbon, activated carbon is saturated with hot air for desorption regeneration.
After comparison, according to the production characteristics and rules of the company, our company wants to use water spray pretreatment (mainly to deal with paint mist and paint powder), adsorption-desorption - catalytic combustion deep purification process to treat the organic waste gas of the company.
(2) Process flow
Spray booth tribenzene waste gas treatment process flow
(3) Design process description
According to the data provided by the owner, each of the 6 spray cabinets is equipped with a fan with 22,000 air volume. Taking into account the initial investment saving, a set of exhaust gas treatment system is designed. The spray gas first enters the water paint spray room through the pipeline for dust treatment, then passes through the preprocessor, and then goes to the activated carbon adsorption bed for adsorption and purification. The saturated activated carbon is desorbed by hot air - catalytic combustion, and the organic waste gas is generated into CO2 and H2O, and then discharged to the standard.
(4) Description of processing equipment
1, paint fog purification room
From the field exhaust pipe analysis, combined with the experience of our company in similar enterprises, the dust removal efficiency of the existing spray cabinet can not meet the requirements of the exhaust gas treatment system, so the design of a paint mist purification room to protect the subsequent exhaust gas treatment system. When the exhaust gas enters the spray painting room, due to the sharp increase of the cross section, the wind speed decreases, and the large dust particles (particles) settle under the action of gravity; The dust-containing gas is affected by the water droplets (fog) emitted from the nozzle during its journey. After the particles are covered by the droplets, they settle down, thus separating the particles from the gas. This process has a good efficiency for the separation of particles, reducing the impact of the dust-containing gas on the subsequent processing process and extending the service cycle of the follow-up equipment. At the same time, the wastewater of the spray painting room can be recycled after filtration, sedimentation, biochemical treatment and other processes.
2, preprocessor (paint fog filter)
In order to avoid secondary pollution and protect activated carbon, it is necessary to use dry filter materials with high purification efficiency and no secondary pollution to purify paint mist and water in exhaust gas. This kind of dry filter material is specially developed for paint mist purification characteristics of the material, made of multi-layer flame retardant glass fiber composite, the density gradually increases with the thickness, and then with a layer of different materials to play a supporting role, the multi-layer fiber to the paint fog particles interception, collision, diffusion, absorption and other effects of the paint fog particles contained in the material. The paint mist purification filter produced by our company adopts the special paint mist filter material imported from the United States, which has the advantages of high combined purification efficiency, large paint mist capacity (3kg-8kg/m2), easy cleaning, low operating cost, no secondary pollution and so on.
(1) The frame is made of metal mesh, and the filter material is inside. The filter is installed in the metal box and replaced regularly.
(2) The filter material is made of synthetic fiber non-woven fabric and aluminum composite, which has the characteristics of large ventilation, small resistance and large dust capacity.
3, activated carbon adsorption bed
It is a kind of industrial treatment method to adsorb organic waste gas by using the adsorption characteristics of activated carbon. The activated carbon adsorption bed adopts a new type of activated carbon, which has large specific surface area and porosity, strong adsorption capacity, good mechanical strength, chemical stability and thermal stability, and purification efficiency up to 95%. The organic waste gas is in contact with the activated carbon through the adsorption bed, and the organic pollutants in the waste gas are adsorbed on the surface of the activated carbon, so as to be separated from the air flow to achieve the purification effect. The air flow discharged from the activated carbon adsorption bed has reached the emission standard, and the air can be directly discharged.
4. Catalytic combustion bed
Before the organic waste gas is introduced into the catalytic combustion device, the waste gas is first preheated by the preheater, and then the electric heater in the catalytic combustion bed heats the waste gas to raise the temperature of the waste gas to about 2800C. Under the action of the catalyst, the thermal reaction generates harmless H2O and CO2, and no electric heating is required at this time. Dispose of high concentration organic waste gas by self-balancing. After combustion, a lot of heat is released, and heat exchangers can be used to recover the high-temperature exhaust gas to reduce the preheating energy consumption. The above process can be fully operated through the PLC system control cabinet.