| VOCs have an important impact on human health and the atmospheric environment.As the most important emission source of VOCs,industrial plants not only have a large quantity but also with a large growth trend.Effective measurement of emission fluxes will enables adopt effective air pollution control policies and evaluated the influence to the surrounding atmospheric environment.Therefore,there is an significant research value and practical meaning for the effective observation of the emission of the industrial park.The onboard solar occultation flux system can realize fast and effective emission source flux measurement and concentration monitoring at multiple points near the emission source in a short period of time,providing convenient and accurate technical methods for performing emission source localization and source strength analysis.Thence,key technologies of onboard solar occultation flux system are studied.A mobile automatic sun tracking system that combines photoelectric tracking system and solar trajectory tracking system is built.Considering the high tracking performance of photoelectric tracking,A two-degree-of-freedom PID control algorithm for on-line self-adjustment of genetic algorithm-backward propagation neural network(GA-BPNN)algorithm is proposed.The experimental results show that the developed automatic sun tracking system achieves the optimal tracking performance and anti-jamming performance at the same time,and has a stable and fully automatic tracking performance.The daily accumulated tracking error for a hundred days is 1.225°,which is less than the 3.828° when switching to the photoelectric mode and meets the requirements.The tracking speed of the photoelectric tracking is less than 100ms,and the accuracy is less than 15mrad.The measured signal-to-noise ratio of the spectrum is greatly improved.The influence factors of the calculation results of the discharge flux were analyzed.The method of effective wind speed correction based on the vertical wind speed profile of the gas effective height for the calculation of emission flux was studied.a experiments with the filed measured vertical wind speed profile,logarithmic and composite ex-ponential vertical wind speed profile to calculate the flux is presented.Without the actual measured wind speed vertical profiles,A calculation model with composite ex-ponential vertical wind speed profile and the effective plume height is proposed.The source apportionment that combines with the Gaussian diffusion model and the onboard solar occultation flux system is studied.An emission source location method that regard correlation of concentration distribution as an evaluation function and a method of source strength inversion with genetic optimization algorithm are proposed.Besides,the main factors that cause calculation error are analyzed.At last,the source gas release experiment results were verified by the method.Based on the above research,the onboard solar occultation flux system was used for multiple key pollution emission sources and many field monitoring experiments were conducted,and the experimental results were analyzed.The large number of field experiments indicts that the system has a high stability and automation,providing effective monitoring means for multi-point sources,unorganized emission sources,etc.Providing strong data support for providing atmospheric control measures and assessing the impact of typical sources on the surrounding environment. |
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