Basic Study On Emission Standard Of Volatile Organic Compounds From Printing Industry Of Hubei Province

In order to formulate the VOCs emission standard of printing industry,this study takes the emission of VOCs in the printing industry in Hubei Province as the research object,the main production processes,industrial scale,pollution generation links,and VOCs emission levels in the printing industry in Hubei Province were obtained through field investigation and data collection.Then the methods of analogical analysis,on-site monitoring,and model calculation are adopted to determine the control factors and emission limits of VOCs,so as to put forward control measures for VOCs in the printing industry.This research provides technical support for the formulation of the "Emission Standards for Volatile Organic Compounds in the Printing Industry in Hubei Province".It is of great practical significance to for promoting the source control of VOCs in the printing industry and improving the overall governance of the industry.(1)By the end of 2016,the total number of printing enterprises in this province was 2,801(excluding copying,photocopying,and typing units),and there were more than 70,000 employees is these enterprises.The chemical raw materials include inks,fountain solutions,cleaning agents,varnish,adhesives,organic solvents,and so on.The generated VOCs contain benzene,toluene,xylene,ethyl acetate,butanol,acrylic acid,methanol,ethanol,isopropanol,butanol,propanol,acetone,butanone,butyl acetate,etc.In 2016,the total output value of printing industry in Hubei was about 42.699 billion yuan.(2)From the perspective of VOCs emissions,the province’s lithographic and flexographic publications printing companies have low levels of VOC emissions.They are between 10.01 and 46.14 t/a,and the corresponding raw material consumptions are between 68.8 and 345.66 t/a.Paper and plastic soft packaging printing companies is more serious,with production between 63.19 and 1119.33 t/a,corresponding raw material consumption between 109.32 and 1616.23 t/a.From the perspective of VOCs treatment,the printing enterprises taking pollution control measures,mainly large-scale enterprises,account for a minority,and the main technical measures are adsorption treatment and combustion equipment.VOCs of other enterprises are mostly discharged in an unorganized form.The management of VOCs in Hubei still needs to be improved.(3)The determining factors of VOCs pollution control is one of the keys linking in in standard formulation.Therefore,a comparative analysis of the emission of VOCs characteristic pollutants,toxicity,and contribution to O3 has been conducted in this research.From the view of emissions,Hubei province has a large usage of benzene-based solvents in printing industry.In addition,isopropyl alcohol,ethyl acetate,n-propyl acetate,and butyl acetate are also widely used.From the view of the toxicity of raw materials,benzene series is the most toxic,followed by isopropanol and ethyl acetate.From the contribution to O3,the MIR value of benzene series is the largest,followed by ethyl acetate and ethanol.At the same time,five typical enterprises’ monitoring data is used to assess health risk.The results show that the risk values of benzene in both companies exceed the maximum acceptable value(5.0×10-6);for toluene,the risk values of the three companies are close and relatively low;and there is an enterprise’s xylene exceeding the maximum acceptable value.To sum up,benzene,toluene,and xylene are single pollution control factors for VOCs,and non-methane hydrocarbons are comprehensive pollution control factors for VOCs.(4)In order to determine the emission limits for pollution control factors of VOCs,multi-media environmental target value is carried out.Using the threshold limit value and LD50 calculation methods,benzene,toluene,xylene AMEGAH calculation results are 0.038,0.535,0.460 mg/m3 respectively.And the results of DMEGAH are 1.6,188,193.5 mg/m3.These results provide a reference for the coming determination of the emission limits for VOCs pollution control factors.(5)According to the status survey of the printing industry in Hubei Province,typical enterprises’ monitoring data,the results of the multi-media environment target values and analogical results with related standards in other places,the emission limits for the VOCs in the printing industry in Hubei Province are determined.The results are as follows:Limits of printing ink VOCs content in offset printing ink is 3%for sheet/cold solid ink,10%for thermoset rotary ink,40%for iron ink,10%for water-based convex ink,and 30%for solvent-based printing ink,30%for water-based gravure ink,50%for solvent-based gravure ink.The Maximum allowable emission concentrations of organized exhaust are:0.5 mg/m3 for benzene,3 mg/m3 for toluene,10 mg/m3 for xylene,50 mg/m3 for non-methane total hydrocarbons,and the maximum permissible emission rates of exhaust are:0.1 kg/h for benzene,0.3 kg/h for toluene,0.5 kg/h for xylene,1.5 kg/h for non-methane total hydrocarbon.The maximum allowable emission concentrations of the unorganized emission monitoring sites are 0.1 mg/m3 for benzene,0.4 mg/m3 for toluene,xylene 0.2 mg/m3,and 2.0mg/m3 for non-methane total hydrocarbon.(6)The printing industry in Hubei should strengthen pollution control of VOCs from the source to process,end and integration to improve the overall governance of the industry.The implementation of the standard can effectively promote enterprises to gradually phase out the use of high-VOCs inks and other raw materials,which will greatly reduyce the emission concentration of VOCs,and indirectly promote the reduction of PM2.5 and O3 concentrations in the atmosphere.The implementation of the standard play a significant role in improving the quality of atmospheric environment in Hubei Province,and the ecological environment benefits are obvious.