Industrial SO2 emission monitoring through a portable multichannel gas analyzer with an optimized retrieval algorithm

摘要

SO variability over a large concentration range andinterferences from other gases have been major limitations in industrialSO emission monitoring. This study demonstrates accurate industrialSO emission monitoring through a portable multichannel gas analyzerwith an optimized retrieval algorithm. The proposed analyzer features alarge dynamic measurement range and correction of interferences from othercoexisting infrared absorbers such as NO, CO, CO, NO, CH,HC, NO, and HO. The multichannel gas analyzer measures 11different wavelength channels simultaneously to correct several majorproblems of an infrared gas analyzer including system drift, conflict ofsensitivity, interferences among different infrared absorbers, andlimitation of measurement range. The optimized algorithm uses a thirdpolynomial instead of a constant factor to quantify gas-to-gas interference.Measurement results show good performance in the linear and nonlinearranges, thereby solving the problem that the conventional interferencecorrection is restricted by the linearity of the intended and interferingchannels. The results imply that the measurement range of the developedmultichannel analyzer can be extended to the nonlinear absorption region.The measurement range and accuracy are evaluated through experimentallaboratory calibration. Excellent agreement was achieved, with a Pearsoncorrelation coefficient () of 0.99977 with a measurement range fromapproximately 5 to 10 000 ppmv and a measurement error of less than2 %. The instrument was also deployed for field measurement. Emissionsfrom three different factories were measured. The emissions of thesefactories have been characterized by different coexisting infraredabsorbers, covering a wide range of concentration levels. We compared ourmeasurements with commercial SO analyzers. Overall, good agreement wasachieved.