Study The Formation Mechanism And Influence Factor Of Organic By-products Resulting From Decomposition Of Toluene By DBD—Development And Application Of DBD Device And Trace Organics Detection Device

Plasma technology has broad application prospects for treatment of low concentration organic waste gas, has been the subject of interest in the research institutions of all countries. At present, the removal rate of organic waste gas was the main research direction, focused attention on the extent to which organic waste gas was degraded into other substances, however, there were no systematic study report on the composition, concentration, formation mechanism and influencing factors of toxic byproducts in the tail gas. This paper study on the formation mechanism of organic by-products in the process of toluene degradation by plasma, on the base of the design of non-thermal plasma generator and PTR-TOF-MS for detecting trace volatile organic compounds. The main research contents of this paper were:(1)The development of the non-thermal plasma generator. Design and manufacture of coaxial dielectric barrier discharge device, Optimization of structural parameters and electrical parameters of non-thermal plasma generator by studying the influence of dielectric layer number, dielectric material, air gap, excitation voltage amplitude and frequency on the discharge characteristics. The developed DBD device can produce stable non-thermal plasma for the degradation of toluene.(2) Design of the key structure and test the performance of the PTR-TOF-MS. Due to the composition of organic byproduct was complex and its concentration was low, the high sensitivity PTR-TOF-MS was used to detect the organic by-products that produced by degradation of toluene in this paper. The drift tube and the transmission device were simulated by the ion optics simulation program SIMION, according to the result of simulation to guide the design and debugging of the instrument, and a real time on-line monitoring device for VOCs was developed whose detection limit was ppt order in one second. The performance of PTR-TOF-MS was tested, for example the ion transmission rate, resolution, sensitivity, detection limit and quantitative accuracy. PTR-TOF-MS was used to detect the composition and concentration of the organic byproducts that produced by degradation of toluene.(3)Study on degradation of toluene by plasma. Degradation of toluene by means of the non-thermal plasma generator, Real time on-line monitoring of tail gas that comes from the degradation of toluene with high sensitivity PTR-TOF-MS, qualitative and quantitative analysis of organic by-products; the plasma parameters affecting the formation of organic by-products were systematically studied, to explore the key factors that inhibit the formation of organic by-products; according to the concentration of organic by-product in the tail gas and VOCs emission limits recommended by the National Institute for occupational safety and health to complete the risk assessment of two organic by-products.