Method And Experimental Research On Performance Improvement Of Odor Gas Detection System

Odor pollution is a kind of special air pollution,which not only has a serious impact on the ecological environment,but also causes great harm to the health of the human body.The detection and treatment of malodors should become urgent.Existing laboratory malodor detection system in the performance there are still some problems,including high detection limits,poor stability and accuracy of the instrument.Therefore,the instrument needs to be improved and optimized to improve the performance of the instrument.In this paper,the principle and components of the on-line detection system based on gas chromatography are described in detail and we also emphatically introduce the chip column.After summarizing the current problems in the system,research and experiment of optimization method are carried out from Hardware and software.In view of the high detection limit of malodorous gas detection instruments developed by the project team,preconcentration methods and experimental studies were carried out,and the preconcentration device based on the principle of adsorption-desorption was developed.Different types of gases for different adsorbents were experimentally studied to determine the best experimental conditions,reducing the detection limit of the system;improve the sampling device,adjusting the gas part of the normal measurement,low concentration measurement Two kinds of measurement modes;improved the sealing method of the chip,improved the sealing of the chip and reduced the gas adsorption;finally,analyzed and designed the hardware circuit,realized the system integration,provided a stable Working conditions.According to the type of system noise,the filtering method of the median filter combined with the wavelet transform was determined,and the singular noise and Gaussian noise were removed;the starting point,the peak apex,and the termination point of the peak were determined by the amplitude method and the increasing slope method,and the chromatogram was realized.The search for peak feature points;for the qualitative and quantitative determination of substances,the absolute retention method and the external standard method are used.Through experiments,the detection and calibration of the chromatographic peaks were effectively achieved,and the accuracy of the system was improved.Finally,this paper completes the stability,repeatability,accuracy,linearity,and detection limit experiments.Observe baseline changes within a certain period of time.The standard deviation of the system is 0.38,and the stability is good.Repeatability and accuracy experiments are performed with dimethyl sulfide,benzene,and toluene mixtures.Repeatability errors and accuracy deviations are all less than 5%,to meet the instrument requirements;use of isobutylene gas linearity experiment,the correlation coefficient is 0.9980,compared with the existing chromatograph on the market,good linearity;the final test for the system detection limit,to achieve 25 ppb dimethyl sulfide detection.