Design Of Multi-angle Light Scattering Nephelometer System Applied To The Study Of DBD Degradation Exhaust Particles

Among the treatment technologies of volatile organic compounds,non-thermal plasma degradation technology has attracted much attention because of its wide application range,low energy consumption,high degradation efficiency,and low use cost.Due to the complex types of active particles in non-thermal plasma and many influencing factors,the study of the components and physicochemical properties of non-thermal plasma degradation of volatile organic compounds in the exhaust gas is of great significance for studying the mechanism of volatile organic compounds reaction and optimizing the reaction conditions.At present,the research on the degradation of VOCs tail gas by nonthermal plasma is mostly focused on gaseous by-products,and the research on aerosol particulate matter is less.In this paper,a device for degrading volatile organic compounds of dielectric barrier discharge is built,and a multi-angle light scattering nephelometer is developed.It laid the foundation for measuring the scattering phase function of aerosol in the exhaust gas of DBD degradation,inversion of physical parameters such as particle size distribution and refractive index of aerosol.The main work and conclusions are summarized as follows:(1)Based on the Mie scattering theory,the effects of particle size and refractive index on the light scattering distribution were simulated by using Matlab software.The results show that the intensity of the scattered light as a function of the scattering angle is very sensitive to the size and refractive index of individual particles.Therefore,for uniform spherical particles that satisfy the single scattering condition,as long as the change of the scattered light intensity of the particles with the scattering angle can be accurately obtained,the physical information such as the refractive index and particle size of the particles can be retrieved using the Mie scattering principle.(2)Designed and processed a wire barrel dielectric barrier discharge reactor.A low temperature plasma discharge degradation toluene experimental system was built.The experimental process and experimental analysis method of toluene degradation by dielectric barrier discharge were studied.It has created conditions for the study of lowtemperature plasma degradation of volatile organic compounds tail gas aerosols.(3)Based on the investigation of light scattering nephelometer meter solutions at home and abroad,a set of multi-angle light scattering nephelometer meter measurement system was designed and built.It can realize the measurement of the relative intensity of scattered light within the scattering angle range of 15°～165°.The angular resolution of this system reaches 0.7°.The polarized light source part,the scanning detection part and the nephelometer cavity part were studied and designed.The use of Labview platform to complete the motor control and photoelectric detection system software compilation.Secondly,the system debugging and calibration methods are studied,and using DEHS standard particles as an example to verify the accuracy of the system.The experimental results show that the measured values have a good correlation with the theoretical simulation results,The correlation coefficient reached 0.996.