With the rapid development of the printing and packaging industry, the emissions of organic solvents (Volatile Organic Compounds for short, VOC) such as gravure printing machines, laminating machines, and coating machines are increasing.
Among organic solvents, toluene, xylene, etc. have carcinogenic effects, and other organic solvents such as benzenes, esters, and ketones pollute the environment to varying degrees, affecting human health and wasting resources. How to better deal with the organic solvents in the exhaust gas of printing, compounding, coating, paint, etc. has become an urgent problem to be solved in the printing and packaging industry.
At present, voc processing methods include adsorption condensation method, absorption dissolution method, plasma processing method and other methods combined method.
Adsorption includes activated carbon adsorption and molecular sieve adsorption.
Activated carbon adsorption condensation method has been tried in some domestic enterprises such as Henan Weihui Yinlida, but the one-time investment is large, the performance of activated carbon deteriorates with the use of longer time, the adsorption effect becomes worse, and the maintenance cost of replacing activated carbon is larger. The lower the adsorption temperature, the better the adsorption effect. Therefore, it is necessary to cool the high-temperature exhaust gas discharged from the gravure printing machine, laminating machine, coating machine, etc., and the desorbed high-concentration exhaust gas is condensed at a low temperature, thus cooling consumption The electric power is quite large, and it is difficult to handle the mixed solvent with moisture (when desorbed by steam), it is difficult to reuse, and there is the problem of secondary pollution of the water source. Some printing plants can only spend the last The adsorption production line built by millions is dismantled.
The voc adsorption condensation method is more suitable for low temperature occasions such as workshops, and the recovery of voc is worth considering.
Absorption and dissolution
The absorption and dissolution method is divided into aqueous solution absorption method and organic solvent absorption method. The equipment investment is not large, but there are problems such as secondary pollution to the absorption water source and the absorption rate is not too high.
Plasma purification technology
Plasma purification technology uses high-energy electron rays to activate, ionize, and crack the components in the exhaust gas. These high-energy electrons have strong oxidizing properties, so a series of complex oxidation occurs to achieve the purpose of removing voc.