A Remote Sensor System Based on TDLAS Technique for Ammonia Leakage Monitoring

• Published in: Sensors (Basel, Switzerland) Vol. 21; no. 7; p. 2448
• Main Authors: Lu, Hongbin, Zheng, Chuantao, Zhang, Lei, Liu, Zhiwei, Song, Fang, Li, Xiuying, Zhang, Yu, Wang, Yiding
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 02.04.2021; MDPI
• Subjects: 2f/1f signal processing technique; Agricultural production; Ammonia; Environmental protection; Industrial production; Lasers; Leak detection; Luminous intensity; Remote sensing; remote sensor; Remote sensors; Semiconductor lasers; Sensors; Signal processing; Spectrum analysis; Stability analysis; tunable diode laser absorption spectroscopy; Tunable lasers; Water vapor; Wavelength modulation; wavelength modulation spectroscopy; wavelength-locked; wavelength-locked; wavelength modulation spectroscopy; remote sensor; tunable diode laser absorption spectroscopy; 2f/1f signal processing technique
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s21072448

The development of an efficient, portable, real-time, and high-precision ammonia (NH ) remote sensor system is of great significance for environmental protection and citizens' health. We developed a NH remote sensor system based on tunable diode laser absorption spectroscopy (TDLAS) technique to measure the NH leakage. In order to eliminate the interference of water vapor on NH detection, the wavelength-locked wavelength modulation spectroscopy technique was adopted to stabilize the output wavelength of the laser at 6612.7 cm , which significantly increased the sampling frequency of the sensor system. To solve the problem in that the light intensity received by the detector keeps changing, the signal processing technique was adopted. The practical application results proved that the signal processing technique had a satisfactory suppression effect on the signal fluctuation caused by distance changing. Using Allan deviation analysis, we determined the stability and limit of detection (LoD). The system could reach a LoD of 16.6 ppm·m at an average time of 2.8 s, and a LoD of 0.5 ppm·m at an optimum averaging time of 778.4 s. Finally, the measurement result of simulated ammonia leakage verified that the ammonia remote sensor system could meet the need for ammonia leakage detection in the industrial production process.