Study On Sulfur Dioxide Concentration Measurement Based On Fluorescence Method

Abstract Sulfur dioxide is one of the major pollutants in air. Its monitor is of great significance to environment protection. Presently what is most commonly applied to the measurement of sulfur dioxide is the chemical method, which requires complicated instruments and equipment, and complex operative process, but the result of which is apt to be interfered by certain substances. Hence, the physical method, which seems to be more effective and efficient, tends to take the place of the chemical measurement. And some reports on the physical measurement of the concentration of sulfur dioxide have already appeared in publication in some foreign countries. According to the reports, the UV (ultra violet) fluorescence method has already been greatly attended for its good selectivity and high sensitivity. As fluorescence is likely to be influenced by the light source fluctuation and the temperature of the sample, devices for light intensity remedy and temperature control are applied in the measuring instrument. This present thesis, based on monitoring data of sulfur dioxide in flue-gas, attempts to justify the linear relationship between the concentration of the sulfur dioxide and the intensity of fluorescence, which is valid within certain limits. And based on it, the author gives a new design of measuring the concentration of the sulfur dioxide. The abstraction of fluorescence signal and pair-channel-differential measurement is successful. The influence exercised to the measurement by the sample flow, the variation in temperature and light source is studied. And with an analysis on the differential method抯 restraint of the variation in temperature and the intensity of light source, the author proposed a new scheme in eliminating the effects.