Research On VOCs Emission List And Control Strategy Of Typical Plastic Flexible Packaging Enterprises

The hazards of Volatile Organic Compounds(VOCs)are mainly in two aspects,one is directly harming human health,and the other is participating in the formation of pollutants such as ozone and secondary aerosol near the ground.At present,China's control of industrial source VOCs is at a critical stage,and the plastic flexible packaging production industry as a key VOCs emission control object still needs more detailed research on VOCs emissions and management countermeasures.Therefore,through the study of typical plastic flexible packaging enterprises,this paper proposes a set of practical and precise control strategies for VOCs of this type of enterprisesThe VOCs list of typical enterprises shows that for enterprises with an annual output of 260 million meters of plastic flexible packaging products,the total input of VOCs is 1950.09t,the main sources are organic solvents(73.68%),inks(21.53%)and adhesives(4.79%);The main production links of VOCs are the printing process and the compound process.The concentration of TVOCs in the two workshops is 70.77mg/m3 and 40.18mg/m3.The main components are ethyl acetate,n-propyl acetate,n-butyl acetate,isopropanol,ethanol,n-pentane,isopentane,acrolein,etc.The characteristic species of the printing workshop are methylcyclohexane,benzene,compound workshop.The characteristic species are acetone,tetrachloroethylene,cis&trans-2-pentene.The main emission links of corporate VOCs are exhaust pipes,which are organized emissions.The concentration of TVOCs is 7.79 mg/m3.The main species of VOCs are ethanol,ethyl acetate,isopropanol,acetone,carbon disulfide,ethylene,toluene,and propylene.The enterprise adopts the method of adsorption concentration+incineration to process VOCs,the efficiency can reach more than 99%,The annual VOCs of the company's organized emissions are 13.51t,and the unorganized volatiles are 184.73tThe VOCs reactivity list with ozone generation potential(OFP)as the reactive index shows that among the VOCs emitted by plastic flexible packaging enterprises,ethyl acetate,n-propyl acetate,ethanol,isopropanol,and n-butyl acetate are A large amount results in a high concentration,resulting in a large OFP contribution.Olefin and aromatic hydrocarbons in inks and adhesives are highly reactive and have high MIR values,which contributes to a relatively high OFP contributionAn analysis of the current status of the company's VOCs supervision found that there are strong consistency of VOCs emission standards in various regions of the country,and the monitoring index and the limit concentration are relatively loose,but for the monitoring index "TVOCs",different agencies have different monitoring standards based on their monitoring standards.The results are quite different.In the stage of total VOCs reduction,it is recommended that after establishing the relationship between the total non-methane total hydrocarbon concentration and the total VOCs concentration of the enterprise,the total non-methane total hydrocarbons should be used as a comprehensive indicator for monitoring and management.On the basis,based on emissions,ozone generation potential,secondary aerosol generation potential,etc.,the VOCs under key control are added as a single indicator for monitoring and management.Evaluate the emission reduction measures of VOCs in enterprises.In terms of source reduction,after all enterprises use low-VOCs raw and auxiliary materials,they can also reduce VOCs input by 228.68t.The enterprise collects VOCs by creating an overall negative pressure environment in the workshop,and uses zeolite rotor adsorption+regenerative catalytic oxidation devices to achieve the effects of 90.25%VOCs collection efficiency and 99%removal efficiency.At present,enterprises can strengthen the management of ink,adhesive preparation process,transportation transfer process and cleaning operations to improve the collection efficiency of VOCs.For new and renovated enterprises,the use of single-solvent gravure instead of mixed-solvent gravure is promoted.At this time,the use of concentration+solvent recovery after the exhaust gas is trapped can effectively reduce the cost of VOCs treatment and increase the recycling rate of resources.