Method for measuring low concentration SO2 based on gas difference absorption cross section characteristics

Abstract

The invention provides a method for measuring low concentration SO2 based on gas difference absorption cross section characteristics. The method comprises the following steps: firstly, primarily selecting a measuring spectrum scope of SO2 according to the SO2 ultraviolet absorption characteristics; secondly, calculating multiple difference absorption cross sections on the basis of multiple known SO2 concentrations according to a DOAS algorithm under the condition of unchanged temperature and pressure and gradually reducing the measuring spectrum scope according to the difference absorption cross section characteristics; thirdly, utilizing a statistic and standard deviation method to screen the spectrum sampling data point in a selected measuring spectrum scope and establishing an optimal sampling point data set, thereby acquiring an optimal difference absorption cross section data set; and lastly, utilizing the optimal difference absorption cross section data set and the DOAS algorithm to inverse the sulfur dioxide gas concentration. According to the method provided by the invention, the measurement principle is simple, the lower limit of the measurement is as low as 3ppm, the low-concentration gas can be accurately measured under a short optical path condition, the relative error can be controlled within + / -1.6% and the scale span error can be controlled within + / -1.2%.

Description

technical field [0001] The invention belongs to the technical field of ambient gas concentration detection and differential optics, and in particular relates to a method for measuring low-concentration SO2 based on gas differential absorption cross-section characteristics. 2 Methods. Background technique [0002] Thermal power plants are one of the main sources of electricity in my country. With the vigorous construction of coal-fired power plants, coal combustion treatment has become the focus of research. my country is a country with coal as the main energy source, and its coal output ranks first in the world, while the reserves of high-sulfur coal account for 20% to 25% of the total coal reserves; in the national coal consumption, 84% of the total coal is consumed It is used for direct combustion, and a large amount of sulfur dioxide SO will be emitted during the combustion process. 2 , coal-fired sulfur dioxide emissions accounted for more than 85% of the total sulfur d...

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Problems solved by technology

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method for measuring low-concentration SO2 based on gas differential absorption cross-section characteristics. 2 method, to solve SO 2 In the concentration measurement process, there are problems of long optical path, high detection concentration range and high measurement error; it has the following advantages, the lower limit of the measurement concentration can be as low as 3ppm, the short optical path, and the relative error can be controlled within ±1.6%. Range error can be controlled within ±1.2%

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