State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
Sensors (Basel). 2021 Apr 2;21(7):2448. 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.
开发高效、便携、实时和高精度的氨（NH）远程传感器系统对于环境保护和公民健康具有重要意义。我们开发了一种基于可调谐二极管激光吸收光谱（TDLAS）技术的 NH 远程传感器系统，用于测量 NH 泄漏。为了消除水蒸气对 NH 检测的干扰，采用波长锁定波长调制光谱技术将激光的输出波长稳定在 6612.7cm，这显著提高了传感器系统的采样频率。为了解决探测器接收到的光强不断变化的问题，采用了信号处理技术。实际应用结果证明，该信号处理技术对距离变化引起的信号波动具有令人满意的抑制效果。通过 Allan 偏差分析确定了稳定性和检测限（LoD）。该系统在平均时间为 2.8s 时可达到 16.6ppm·m 的 LoD，在最佳平均时间为 778.4s 时可达到 0.5ppm·m 的 LoD。最后，模拟氨泄漏的测量结果验证了该氨远程传感器系统能够满足工业生产过程中氨泄漏检测的需求。
