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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 semiconductor laser absorption spectroscopy (TDLAS) has the advantages of high selectivity and high accuracy, which provides a reliable technical means for the on-line detection of ammonia slip. Firstly, the effect of temperature on the NH3 concentration was studied. The results showed that the concentration decreased with the increase of temperature at 25 ~ 300 ℃. Then NH3 at 10 ~ 100ppm was detected by TDLAS system at room temperature of 25 ℃ , Collected the second harmonic spectrum. The single-pass and multi-pass cell measurements were compared to obtain a single-pass sample cell with a minimum detection limit of 22.9 ppm and a multi-pass cell with a detection limit of 1.21 ppm. The multi-pass cell significantly enhanced detection Accuracy. The results show that the system can adapt to the field measurement environment.