An ultra-low emission Cl2 monitoring optical system based on differential optical absorption spectroscopy has been set up. We have found through comparison experiments that UV reflection enhanced aluminum is damaged and the dielectric film mirror is intact under high concentration of Cl2. Then verify the performance characteristics of ultralow Cl2 emission online monitoring device. The maximum absorbance of 50ppm Cl2 exceeds 0.1, while the 30ppm Cl2 reaches 0.063, so the measurement range can be 0-95 mg/m3, which meets the maximum allowable emission concentration of Cl2 required by the new regulations for detection of 65mg/m3.
As a Class 2B carcinogen, C8H8 has great hidden danger to human health. Domestic research on the detection of styrene in the atmosphere is relatively lacking. Therefore, this article determined proper retrieval range of wavelength and a method to eliminate interference based on the absorption feature in the UV region. An open optical path detection system was set up based on the principle of ultraviolet differential absorption spectroscopy. The detection limit of C8H8 is 9.0μg/m3 when the optical path reaches 100m. The outdoor field measurement of C8H8 was carried out in Binjiang District of Hangzhou, indicating the daily average variation of styrene gas. The results showed that the maximum concentration of C8H8 is 60.6μg/m3, the minimum concentration is 38.2μg/m3 and the average concentration is 53.5μg/m3.
This paper describes a set of ultra-low smoke emission monitoring optical devices based on differential absorption spectroscopy (DOAS), which mainly includes a xenon lamp source, a sample cell, a spectrometer for light detection, and a Y-type optical fiber. The device utilizes a newly developed ultraviolet long path gas chamber, the energy of the ultraviolet spectrum is high, and the energy of the xenon lamp in the experiment is only enough to meet the application requirements. As well, based on DOAS optical device it has the advantages of high ultraviolet energy, small volume and high measurement accuracy. Therefore, the system solves the difficult problem of low concentration flue gas emission monitoring. The lower limit of detection of SO2, NO and NO2 concentration was 0.21 mg/m3, 0.13 mg/m3 and 0.61 mg/m3, respectively. Comparison of on-site field monitoring with high temperature FTIR (Fourier Transform Infrared Spectroscopy) flue gas emission monitor, the average concentrations of SO2, NO and NO2 measured by the two instruments were less than 14 mg/m3, 39 mg/m3 and 25 mg/m3 respectively, and the correlations were all above 0.995.