The control of VOCs in the printing and packaging industry can be started from three aspects: source reduction, process management, and end management.
Source control aims to promote the use of raw and auxiliary materials such as low-VOCs or no VOCs, such as environmentally friendly inks, adhesives, and cleaning agents, that is, to reduce the VOCs content of raw and auxiliary materials from the beginning of the process, so as to achieve the goal of reducing VOCs.
Process management includes the specification and optimization of the process. Drying is an indispensable process in the packaging and printing process, and it is also one of the links where VOCs are generated and discharged. By promoting the drying device to optimize the control system and implement the curing process, the purpose of VOCs pollution control can be achieved.
In terms of terminal treatment, the organic waste gas treatment technologies commonly used in the packaging and printing industry in China are mainly divided into two categories: one is the solvent recovery technology that separates and recovers VOCs, mainly including adsorption condensation recovery method, absorption dissolution method, suitable for organic solvents And packaging and printing processes that use a large amount of ink and high VOCs concentration; the other is the destruction technology that decomposes VOCs, mainly including thermal oxidation (catalytic combustion, regenerative oxidation), plasma oxidation decomposition method, suitable for flow Large, low-concentration organic pollutant waste gas.
What are the principles and characteristics of VOCs removal by adsorption?
The principle of the adsorption method to remove VOCs: When the gaseous mixture containing VOCs is in contact with the porous solid adsorbent, the unbalanced molecular attraction or chemical bonding force on the solid surface is used to adsorb the VOCs components in the mixed gas on the solid surface to make It is separated from the exhaust gas, so that the gas is purified. The main treatment processes include fixed bed, moving bed and fluidized bed adsorber.
The adsorption method is generally used to treat medium and low concentrations of gaseous pollutants. The adsorption effect depends on the nature of the adsorbent, the types of gas phase pollutants, and the operating temperature, humidity, and pressure of the adsorption system. Activated carbon is a commonly used type of adsorbent, which has a huge specific surface area, adsorption surface structure characteristics, strong selective adsorption capacity, good catalytic performance and surface chemical performance, in the treatment of gaseous pollutants, especially in the VOCs Governance plays an important role. In general, the adsorption method has simple equipment, flexible operation and high removal efficiency. It is one of the effective and economical recovery technologies. However, the operating cost is relatively high and secondary pollution occurs.
What are the end control technologies of industrial VOCs?
End treatment technologies can be divided into two categories: recovery and destruction. For high-concentration VOCs exhaust gas, the VOCs in the exhaust gas can be recycled and reused by condensation, absorption, adsorption and other technologies first, and other treatment technologies can be supplemented to achieve standard emissions. For medium-concentration VOCs exhaust gas, adsorption technology can be used to recover organic solvents, or catalytic combustion and thermal incineration technology can be used to purify and meet emission standards. For low-concentration VOCs exhaust gas, adsorption concentration combustion technology, biotechnology or plasma technology can be used to purify and meet the emission standards.
