可调谐半导体激光吸收光谱技术(TDLAS)具有高选择性、高准确性的优点, 为逃逸氨的在线检测提供了可靠的技术手段。首先研究了温度对NH3浓度检测的影响, 表明在25-300℃之间, 浓度随温度的升高而降低；然后在室温为25℃时, 利用TDLAS系统对浓度为10-100ppm 的NH3进行检测, 采集得到其二次谐波光谱。比较了单光程和多光程样品池测量结果, 得到单光程样品池最低检出限为22.9ppm, 多光程样品池的检测限为1.21ppm, 多光程样品池能够明显地提高检测精度。结果表明, 该系统能够适应现场测量环境。

Tunable diode laser absorption spectroscopy (TDLAS) with the advantages of high selectivity and high accuracy provides a reliable means of on-line detection technology for escaping ammonia. The NH3 concentration detection is studied. Firstly, the influence of temperature is studied, and the experiments show that between 25-300℃, the NH3 concentration is decreased with the increase of temperature. Then, the concentrations of 10-100ppm NH3 are detected with the TDLAS system, and their second harmonic spectrum are collected in single optical path pool and multi-optical path pool at 25℃. The detection limit of the single optical path pool is 22.9ppm and the multi-optical path pool is 1.21ppm. The results show that the system can be adapted for the on-line monitoring of NH3 concentration in field.