High precision synchronous detection method for multi-gas using the least square fitting

Tingting Zhang; Jie Hu; Yubin Wei; Yanfang Li; Zhaowei Wang; Tongyu Liu

doi:10.1117/12.2579816

5 November 2020 High precision synchronous detection method for multi-gas using the least square fitting

Tingting Zhang, Jie Hu, Yubin Wei, Yanfang Li, Zhaowei Wang, Tongyu Liu

Proceedings Volume 11567, AOPC 2020: Optical Sensing and Imaging Technology; 115672B (2020) https://doi.org/10.1117/12.2579816
Event: Applied Optics and Photonics China (AOPC 2020), 2020, Beijing, China

Abstract

Tunable diode laser absorption spectroscopy (TDLAS) technique has been widely investigated for gas concentration measurement in both industry and laboratory. In order to detect different gases within the multi-gas mixture based on TDLAS, different types of schemes have been developed, such as wavelength division multiplexing, time division multiplexing and so on. However, there are many drawbacks of the above methods, and the sensitivity and accuracy of multi-gas detection have been greatly restricted, the effect of cross-talking interferences becomes a technical bottleneck for multi-gas detection. Therefore, a high accuracy synchronous detection technology for multi-gas detection using the least square fitting is reported. The wavenumber of 6380cm^-1 has been selected to detect CO and CH₄. Because the absorptivity of CH₄ and CO is less than 0.1, the least square fitting method can be used to calculate the concentrations of CH₄ and CO simultaneously. This novel method has been shown to improve the precision achieved in the detection of multi-gas by 18%, compared with the precision measured at another wavelength. The Allan variance results indicate that the optimal integration time has been improved from 50s to 100s, the minimum measurement precision of CH₄ and CO is ~0.45% and ~0.46 10-6 respectively. Meanwhile, the detection cost and response time can be reduced obviously.

Citation Download Citation

Tingting Zhang, Jie Hu, Yubin Wei, Yanfang Li, Zhaowei Wang, and Tongyu Liu "High precision synchronous detection method for multi-gas using the least square fitting", Proc. SPIE 11567, AOPC 2020: Optical Sensing and Imaging Technology, 115672B (5 November 2020); https://doi.org/10.1117/12.2579816

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