Characteristics And Control Technology Of Volatile Organic Compounds Emission From Solvent Use Sources

Volatile organic compounds（VOCs）are the key factors to curb the growth of ozone pollution in our country and further reduce PM_2.5,and the use of organic solvent is an important source of anthropogenic VOCs emissions.There are many kinds of organic solvent products in China,and the content of VOCs is unknown.However,there are few actual measurement studies related to organic solvents.In order to fill the gap in this field,we carry out the research on the characteristics and control technology of VOCs from solvents use soures.Based on a large number of sampling tests,the VOCs content and composition characteristics of coatings/inks were figured out,the removal efficiency of common VOCs control technology was obtained.Based on the above results,the industry emission coefficient system and the emission list of organic solvent use sources in China was established,and corresponding control suggestions were proposed.Among the tested organic solvents,solvent-based automotive original paint（60%）,solvent-based ink（59%）,solvent-based automotive repair paint（55%）and other solvent-based products have higher average content of VOCs.The average VOCs content of environmentally friendly products,such as waterborne automotive coatings,waterborne wood coatings,and waterborne container coatings,is in the range of 8%to 18%,while the VOCs content of waterborne architectural coatings,waterborne inks,and UV inks is generally less than 3%.The level of VOCs in solvent-based products is much higher than that of water-based products and UV products.The average value of the VOCs content of different types of samples can basically meet the current mandatory national standards,but there are a small number of samples that exceed the standard.The main components and OFP contributors of water-based coatings were alcohols and ethers,and for solvent-based coatings,they were benzene series and esters,while for UV coatings,they were esters,alcohols and ethers.In the use of most organic solvents,benzene series contribute the most to SOAFP.Among the 14 types of VOCs control technology tested,the high-efficiency treatment technologies are RTO（92%）,RCO（90%）,adsorption+catalytic combustion（90%）and other combustion technologies.The treatment effects of activated carbon adsorption（31%）,UV photolysis purification（44%）,low temperature plasma treatment（25%）and their combined technologies are not ideal.Various control technologies have different treatment capabilities for each species of VOCs.Among them,combustion technologies have strong treatment capabilities for various components,but it will produce new species with low concentrations during the treatment process.Based on the above results,the total emissions of VOCs from organic solvents in China was about 1.45 million tons in 2017,of which the furniture manufacturing industry had the largest emissions（54 million tons）,followed by the construction and decoration industry（400,000 tons）.End treatment can only reduce about 20%VOCs emissions.In the future,the government should deepen the implementation of national standards to limit the content of VOCs in organic solvent products,and strengthen the supervision and guidance of enterprises to improve the reduction of VOCs in end treatment.