Researchondegradationefficiencyandaerosolsize Distributionoftypicalindustrialorganicgasesbynon-thermal Plasmatechnology

The degradation of VOCs by Non-Thermal Plasma technology has become a research hotpot in the field of environment in recent years due to its advantages of small occupation area,high degradation efficiency,low consumption and less by products.The effect of parameters(applied voltage,residence time and initial concentration of pollutants)on the degradation efficiency of toluene,acetone and their mixtures by NTP was studied in this paper The Aerosol size distribution was monitored by scanning electromobility particle size analyzer(SMPS).The study found:(1)In the process of degrading VOCs by NTP,the VOCs were degraded into gaseous by-products,then polymerized to form particulate matter,and finally converted into CO2.The higher applied voltage is beneficial to the improvement of decomposition efficiency of VOCs and the complete conversion of VOCs into gaseous products such as CO2.(2)Because of the difference in structure,toluene is the most easily polymerized to form particulate matter,and its degradation by-products are benzoquinone,benzaldehyde,benzoic acid,benzyl alcohol,phenol,etc.The byproducts of acetone degradation include ethynyl methanol,dimethyl ether,ethanol,Acetaldehyde and 3-butene-2-ol.Ethyl acetate degrades more to CO and CO2.(3)The mineralization of VOCs degradation rate increased with the residence time of organic compounds in discharge system,and the degradation rate of ethyl acetate and acetone reached the highest after a period of residence time,and the longer residence time could promote the degradation and transformation of toluene;When the voltage is more than 7.5 kV,the residence time has little effect on the removal of VOCs.(4)With the increase of the initial concentration,the VOCs removal rate and mineralization rate will decrease gradually,but when the VOCs concentration is too low relative to the energy of the discharge system,the VOCs removal rate will not be affected by the concentration increase.When the initial concentration increased from 200 PPM to 700 PPM,the removal rate of ethyl acetate decreased by 2.4%-3.6%,the removal rate of acetone decreased by 3.7%-10.7%The removal rate of toluene decreases by 6.2-36.9%with the increase of the initial concentration,and the resultant particulate matter also increases.Thus,diluting toluene and increasing the concentration of ethyl acetate and acetone during degradation can increase economic benefits.(5)The degradation rate of the mixed samples by NTP is generally higher than that of the single substance,and the particles produced by NTP degradation are much smaller than the sum of the particles produced by the three substances alone However,only 18-26%of the CO2 produced by the degradation of the three organic compounds was converted into CO2.In conclusion,both increasing the discharge voltage and decreasing the initial concentration of pollutants can avoid the formation of aerosols and gaseous by-products,and the influence of residence time on the formation of particles may be related to the types of pollutants.The combined degradation can not only improve the degradation rate but also avoid the production of particulate matter.In practical application,considering the external factors,it is necessary to set up a suitable degradation scheme according to the purpose of degradation...