Deconvolution For Improving The Measurement Spectral Resolution Of Flue Gas Absorption Spectra

In on-line measurement of gas absorption spectrum, the instrument function causes spectral distortion and low spectral resolution. As the measured spectrum is a convolution of the real spectrum and the instrument function, deconvolution is introduced to reconstruct the real spectrum.First, several deconvolution methods was introduced in detail, especially the nonlinear fitting deconvolution method. Secondly, the spectral resolution and its affecting factors were analyzed, and the mercury lamp spectrum was the instrument function of different spectral resolution, in different slit width but equal import and export slit. Thirdly, in practical measurement, it must have been satisfied that the monochromator was consisted with the reference spectrum, because of different resolution. In order to satisfy the consistency, the deconvolution was introduced to reconstruct the real spectrum as a standard reference spectrum. Then the spectrums reverted were convoluted with the instrument function of the monochromator to realize the consistency. The nonlinear fitting deconvolution method was used to reconstruct the real UV absorption spectrum of SO₂, and turned out to improve the measurement spectral resolution of gas absorption spectra. Finally, the influence of pressure and temperature on absorption cross-section was given further research, and the spectrum after deconvolution and the measured spectrum were compared; for improving the measurement spectral resolution of gas absorption spectrum, the errors in deconvolution were analyzed.It is shown in theoretical analysis and the results that the deconvolution has wide application prospects. The studying of this paper provided the theoretic and experimental bases of the deconvolution applied successfully in gas absorption spectrum, and provided the technical support to improve the measurement spectral resolution.