Research On Key Technologies For Continuous Rapid Capture And Enrichment Of Volatile Organic Compounds In Atmosphere

Atmospheric VOCs is an important precursor for forming fine particles(PM2.5)and ozone,and the proportion of atmospheric VOCs in PM2.5 is about 20% to 40%,and some PM2.5 is converted from atmospheric VOCs.Atmospheric VOCs not only has a great impact on the environment,but also has different degrees of damage to the human nerves and viscera.With the continuous development and progress of society,the contribution of industrial pollution and traffic pollution to atmospheric VOCs generation is increasing.Due to the danger of atmospheric VOCs,it is necessary to take some measures to protect human beings from being harmed.Therefore,it is also urgent to explore an efficient and rapid capture of atmospheric VOCs equipment in the ambient air,and to monitor it in real time,and also facilitate access to the current pollution situation and respond by some electronic means.In this paper,the standard gas of a certain concentration is taken as the research object,and the capture effect of the instrument on certain concentration standard gas is studied by changing the reaction conditions.The main research contents include cryogenic condensation capture technology and adsorption trapping technology.The cryogenic condensation trap technology is to capture,enrich and enrich the atmospheric VOCs under ultra-low temperature.The technology of adsorption trapping is to capture atmospheric VOCs by adsorbent with large surface area,porous structure and strong adsorption capacity.In the study of cryogenic condensation capture technology,the factors that may affect the capture performance include 08 chiller temperature,04 refrigerator temperature,sampling mode difference,standard gas wetting,and monitoring standard gas.The experimental results show that when the temperature of the 08 refrigerator is set to(-65 C--35 C),the super difference(that is,the measured concentration range is not more than 2.8-5.2ppb)is far less than 30%;when the temperature of the 04 refrigerator is set to(-30 C--20 C),the super difference is far less than 30%;the standard gas is humidified,and the acetone and methyl tert butyl ether can be obtained.The enhancement of capture performance of such oxygenated compounds has a certain effect.And the sampling method did not improve the trapping performance before and after changing the type of standard gas,but the trapping performance was in good condition.Adsorption trapping technology at the time of the study,the main consideration is the effect of adsorption on the mesh.In the test of first order adsorption and two stage adsorption,it is found that the relative deviation between the results and the initial concentration is always near 30%,and the related techniques need to be further studied.