SO3 is one of the most important precursors of condensable particulate matter,and easily transferred into blue flue gas after emission,which causes adverse effects on the atmospheric environment.SO3 is also corrosive and hazardous gas.It is necessary to measure and monitor its concentration in flue gas.At present,the results and accuracy for methods monitoring SO3 in flue gas are difficult to judge and equipments need to be calibrated regularly.However,SO3 is reactive and difficult to store in the tank and must be generated on-site.The lack of ready-made standard gas is the major limiting factor for accurate measurement and monitoring of SO3.In this paper,a SO3 generator was developed based on the principle of catalytic oxidation.Its performance,stability,and influencing factors were evaluated.The conversion ratio was stable at 98.5%on the condition that injecting 1000 ppm(μmol/mol)SO2 at a flow rate of 0.1 L/min,loading 600 mg vanadium catalysts(40~60 mesi),and setting the conversion temperature at 430 ℃.By diluting the highly-concentrated SO3 with clean air of different flow rates,the generator linearly outputs SO3 standard gas in the range of 10 ppm to 1000 ppm,which can be used for calibration of measurement and monitoring of SO3.
stationary sourceSO3standard gas generatorcalibrationcondensable particulate matter