Temperature measurement of SO2 based on mid‐infrared laser absorption spectroscopy.

The temperature measurement of Sulfur dioxide (SO2) is a crucial parameter for accurately determining its concentration, particularly in high‐temperature environment. Herein, it is realized by using three different techniques, which are direct absorption spectroscopy, wavelength modulation spectroscopy and non‐calibration wavelength modulation spectroscopy based on the bispectral lines temperature measurement method. The bispectral lines of SO2 locates at 1396.844 and 1396.921 cm−1, respectively. The gas temperature in the absorption cell was also measured with K‐type thermocouple and compared with these three spectral measurements. The linearities corresponding to these three techniques are 99.71%, 99.8%, and 99.88%, respectively. Their average relative error between the spectral measurement results and the linear fitting value of the three techniques is 1.15%, 0.86%, and 0.57%, respectively. It is illustrated the feasibility of the bispectral lines method for high‐temperature measurement. These investigations provide methods for temperature measurement in high‐temperature coal‐fired boilers, potentially for investigating other sulfide gas molecules such as SO3 and H2S. [ABSTRACT FROM AUTHOR]