Design And Implementation Of Portable Flue Gas Analyzer

China’s industry keeps growing in recent years,the problems caused by industrial production become increasingly serious.With the growth of investment in the CEMS(Continuous Emission Monitoring System),the need for instruments which are used to detect flue gas concentration of pollutants is increasing gradually.There are a lot of relevant instruments in the market currently;some of them detect the concentration of contaminant by electrochemical analysis,a few of these instruments detect by spectral analysis,but most of them detect the concentration by DOAS(Differential Optical Absorption).However,there are phenomenons of zero drift in the instruments which adopt the method of electrochemical analysis,thus the sensor of the instrument need to be replaced regularly because of its short working life,while it is difficult for the instruments detect concentration by DOAS to measure oxnitride precisely.This article compares the domestic and international mainstream flue gas analyzers.Combined with optical principles,a new measurement method is used to detect gas concentration of smoke.With this method,NO2 is catalyzed and reduced into NO in conversion furnace.Then the concentration of NO is detected before and after reaction.At last concentrations of other gases can be calculated according to the additively of absorbency.This method avoid the problem of interference of different nitrous oxides.This article describes the principle of flue gas analyzers in details and designed the flue gas analyzers based on catalytic reduction.The accuracy of the measurement result was verified by experiments and the error was confined within 3%.The related technical parameters of the analyzer meet the ‘JJG968-2002 flue gas analyzer verification regulation’,which was issued by Ministry of Environment Protection.In this project,the overall structure of the flue gas analyzer was optimized coordinated with the measurement methods and related functions described in the article and portable design and humanized interface was used.