Study On Evaluation And Application Monitoring Methods Of Volatile Organic Compounds In Typical Solvent Using Industries

The compound air pollution mainly based on haze pollution and ozone has become the two most important environmental hazards that governments at all levels pay attention to,and its control measures are becoming more and more scientific.Volatile Organic Compounds(VOCs)are important precursors of PM2.5 and ozone,which has become one of the main pollutants that directly affect China’s composite air pollution.Their monitoring and control technologies need to be improved.Although China has begun to form a set of standard methods and systems for effective monitoring and evaluation for ambient air and exhaust from fixed pollution sources around VOCs,however due to the complex composition of VOCs and the large differences between different industries,by comparing different VOCs characterization indicators and monitoring methods,establishing an efficient VOCs monitoring method in the corresponding industry still has important guiding significance for the environmental supervision and control of VOCs in China.This paper evaluates the applicability of each VOCs monitoring method by combing the definitions of VOCs characterization indicators in different monitoring standards and the main VOCs pollutants in typical solvent using industries;through laboratory research and on-site testing methods,the actual performance of different VOCs monitoring methods was evaluated.Taking the study of VOCs pollution characteristics of related industries in Dezhou,Shandong as an example,the role of different VOCs monitoring indicators in the process is compared.At present,the main monitoring methods are non-methane total hydrocarbons(NMHC)and total volatile organic compounds(TVOC),then the monitoring methods for TVOC have not yet been unified.By comparing the main emission pollutants of the typical solvent using industry with the monitoring objects in the domestic VOCs monitoring standards,it was found that the the pollutant types monitored by Method HJ 759 and Method HJ 734 are more comprehensive;Method HJ 644 lacking the monitoring of aldehydes,ketones,esters and alcohols,meanwhile the main emission pollution of all typical solvent using industries in the three monitoring methods HJ 734,HJ 644 and HJ 759 did not cover every pollutants.By analyzing the TVOC concentration and NMHC concentration of the sample for typical solvent using industry,it is found that the TVOC concentration much lower than NMHC concentration,which may be due to the monitoring of TVOC does not cover all species.At the same time,the correlation between TVOC concentration and NMHC concentration was analyzed,and it was found that the correlation between TVOC concentration and NMHC concentration between HJ 759 and HJ 644 is similar,which both higher than HJ 734 monitoring method correlation.By studying the response of mixed gas for esters,alkanes,aromatic hydrocarbons and alcohols to NMHC and THC on a gas chromatograph,it can be seen that the THC can better respond to these four types of mixtures than NMHC.In addition,THC monitoring method is more efficient than NMHC.Therefore,in actual monitoring,THC can be used instead of NMHC to characterize the concentration of volatile organic compounds.Through monitoring the concentration of NMHC and TVOC(using HJ 734 method)in the four typical solvent using industries in Dezhou(automotive manufacturing,wooden furniture manufacturing,glass fiber plastics manufacturing,packaging and printing):It was found that the NMHC concentration of all samples is higher than that of TVOC.Through analysis of the sample monitoring results of the samples,it was found that the main emission species of the four typical industries in Dezhou are aromatic hydrocarbons and oxygenated VOCs,forming an emission factor library of VOCs components based on local emission characteristics.In view of the experiment,it has been found that THC has a better response to aromatic hydrocarbon compounds,alcohols and esters.In the future measurement,THC can be considered to replace NMHC to characterize the concentration of volatile organic compounds in typical solvent industries.