Enviro - Model ESE-LASER-500 -SO2 Gas Analyzer

• Flue gas continuous emission monitoring ( CEMS ) for the power plants
• DeSOx process monitoring (analyze SO2 and O2)
• Waste incineration flue gas continuous emission monitoring (analyze SO2, NO, NO2 and O2)
• Sulfur recovery process gas analysis (analyze SO2 and H2S)
• On-line air monitoring (analyze SO2,NO2 and O3)

Ultraviolet differential optical absorption spectroscopy (DOAS)

Due to the same gas has different absorption in different spectral band, the absorption of different gases in the same spectral band has superposition effect. Through the analysis of continuous spectrum, a variety of gas can be measured at the same time. The holographic grating is used for light splitting of light absorbed by gas to be measured, sensor array are used to convert the spectral optical signals into electrical signals, after obtaining the continuous absorption spectra of medium, and a variety of gas can be measured at the same time.

Unique algorithms of differential optical absorption spectrum

Gas concentration can be obtained by processing the continuous spectrum data. Light beam through the measured gas environment of which the length is L, due to the gas absorption of light, the light energy will decay. Gas absorption of light intensity in wavelengths, can be accurately expressed by Beer – Lambert relation.

In formula:

• Relative intensity of the incident light in wavelength;
• Relative intensity of the emergent light in wavelength;
• Optical path length;
• The concentration of the ith gas;
• The absorption coefficient of the ith gas;
• The extinction coefficient led by particle scattering and other factors.

Ordinary algorithm can’t distinguish whether the light attenuation is caused by the gas absorption or particle scattering, etc. which is not absorption. The differential absorption method is that the gas absorption is decomposed into two parts: ,  is a part of fast change with wavelength.  is a part of slow change with wavelength. Extinction effect that led by the factors such as particle scattering changes slowly with the wavelength. Obviously, the part of the absorption that varies fast with wavelength is only related to gas absorption. Concentration of gas can be obtained by carrying on the corresponding numerical values. Analyzer optical principle is shown in the diagram (Fig. 1-1) below.