28 August 2009 Exhaust gas monitoring based on absorption spectroscopy in the process industry
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Proceedings Volume 7382, International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging; 738227 (2009) https://doi.org/10.1117/12.831320
Event: International Symposium on Photoelectronic Detection and Imaging 2009, 2009, Beijing, China
Abstract
This non-invasive gas monitor for exhaust gas monitoring must has high reliability and requires little maintenance. Monitor for in-situ measurements using tunable diode laser absorption spectroscopy (TDLAS) in the near infrared, can meet these requirements. TDLAS has evolved over the past decade from a laboratory especially to an accepted, robust and reliable technology for trace gas sensing. With the features of tunability and narrow linewidth of the distributed feedback (DFB) diode laser and by precisely tuning the laser output wavelength to a single isolated absorption line of the gas, TDLAS technique can be utilized to measure gas concentration with high sensitivity. Typical applications for monitoring of H2S, NH3, HC1 and HF are described here together by wavelength modulation spectroscopy with second-harmonic(WMS-2F) detection. This paper will illustrate the problems related to on-line applications, in particular, the overfall effects, automatic light intensity correction, temperature correction, which impacted on absorption coefficient and give details of how effect of automatic correction is necessary. The system mainly includes optics and electronics, optical system mainly composed of fiber, fiber coupler and beam expander, the electron part has been placed in safe analysis room not together with the optical part. Laser merely passes through one-meter-long pipes by the fiber coupling technology, so the system itself has anti-explosion. The results of the system are also presented in the end, the system's response time is only 0.5s, and can be achieved below 1×10−5 the detection limit at the volume fraction, it can entirely replace the traditional methods of detection exhaust gas in the process industry.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Shuai Zhang, Shuai Zhang, Wen-qing Liu, Wen-qing Liu, Yu-jun Zhang, Yu-jun Zhang, Xiao-wen Shu, Xiao-wen Shu, Rui-feng Kan, Rui-feng Kan, Yi-ben Cui, Yi-ben Cui, Ying He, Ying He, Zhen-yu Xu, Zhen-yu Xu, Hui Geng, Hui Geng, Jian-guo Liu, Jian-guo Liu, } "Exhaust gas monitoring based on absorption spectroscopy in the process industry", Proc. SPIE 7382, International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, 738227 (28 August 2009); doi: 10.1117/12.831320; https://doi.org/10.1117/12.831320
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