Determination of Gaseous Pollutants in Fixed Source Waste Gas by Fourier Transform Infrared Spectroscopy

This standard specifies the determination of fixed pollution source waste

Portable Fourier Transform Infrared Spectroscopy for Organic Pollutants (SO, NO, NO, CO, CO).

This standard is applicable to the determination of gaseous pollutants (SO, NO, NO, CO, CO:) in exhaust gases from fixed pollution sources.

The detection limit of SO, NO, and CO methods is 1mg/m, and the lower limit of determination is 4mg/m; The detection limit of NO method is 3mg/m, and the lower limit of determination is 12mg/m; The detection limit of CO method is 1g/m, and the lower limit of determination is 4g/m ².

Method Principle

When infrared light with continuous wavelengths shines on the molecules of the substance being measured, infrared light with the same natural vibration frequency as the molecules is absorbed, resulting in an infrared absorption spectrum with wave number as the horizontal axis and absorbance as the vertical axis: different substances absorb infrared light differently, manifested by different frequencies of characteristic absorption peaks. The Fourier transform infrared spectroscopy method converts the light emitted by an infrared light source into interference light through a Michelson interferometer, and then irradiates the gas sample with the interference light to obtain an infrared interference pattern. The computer system then processes the Fourier transform to obtain an infrared absorption spectrum. By comparing the infrared absorption spectra of gas samples with the infrared absorption spectra of standard substances in the standard spectrum library, qualitative analysis of the samples can be carried out: under certain conditions, the characteristic absorption intensity and concentration of the target compound in the infrared absorption spectrum follow the Lambert Beer law, and the target compound can be quantitatively analyzed based on the absorption peak intensity.

instruments and equipment

Fourier Transform Infrared Gas Analysis System

System Composition

The Fourier transform infrared gas analysis system generally consists of a sampling unit, preprocessing device, analyzer, and data processing unit

Among them, the sampling unit includes a sampling tube (including a particulate filter with heating and insulation functions), an air duct, an air pump, etc; The preprocessing device can choose a constant temperature heating device with a heating temperature of ≥ 180C: the analyzer consists of an infrared light source, interferometer, sample chamber, and detector. The data processing unit includes a computer, analysis software, and reference spectra