| The technique of low-temperature plasma degradation that is efficient,low-cost and low-power has emerged as a widely recognized tool for treating the Volatile Organic Compounds(VOCs)with low concentration and high flow rate compared with other treatment technologies.However,in the study of VOCs degradation by low-temperature plasma,it is found that there are aerosol particles in the tail gas.The research on the particle size of aerosol particles is of great significance to clarify the products in the process of VOCs degradation by low-temperature plasma.In this paper,the dielectric barrier discharge(DBD)device was used to generate low-temperature plasma for the discharge degradation of toluene gas.A light scattering turbidimeter was built to measure the scattering phase function of the aerosol in the degradation tail gas,and the particle size information was obtained by inversion.The relationship between the particle size of the aerosol and the plasma degradation conditions was studied,so as to provide the corresponding experimental data for optimizing the degradation conditions.The main work and experimental conclusions are as follows:1.It is found that the size of the aerosol produced by gas discharge is generally less than 1 μ m.And the fine particles below 200 nm are the main part of aerosol,which is lower than the detection limit of commonly used aerosol particle size detection devices or methods.The light scattering law based on Mie scattering theory can meet this requirement.At present,there are few studies on measuring the scattering properties of aerosol produced by gas discharge and retrieving the particle size by light scattering method.It is innovative to build a light scattering turbidimeter based on Mie scattering principle to measure the scattering properties of aerosol produced by gas discharge and retrieve the particle size.2.The plasma degradation system of VOCs was set up to produce aerosols for toluene gas discharge degradation;A light scattering turbidimeter was designed and optimized to measure the scattering phase function of the aerosol produced by the discharge degradation of toluene;Nitrogen and DESH aerosol particles are used as standard particles to calibrate and verify the measurement range and accuracy of the whole light scattering turbidimeter,so that the turbidimeter can be used to study the scattering properties of aerosols produced by low-temperature plasma degradation of VOCs.3.By changing the discharge voltage,residence time of toluene gas and initial concentration of toluene,the aerosol with different particle size can be produced.The aerosol is put into the light scattering turbidimeter to measure the scattering characteristics and retrieve the particle size.It is found that the particle size of aerosol produced by toluene gas discharge is related to the above plasma degradation conditions.The particle size of aerosol produced by gas discharge can be reduced by increasing the discharge voltage,increasing the residence time of gas in the discharge device and reducing the initial concentration of toluene. |
