基于激光吸收光谱乙炔在线监测技术的研究

The Development of Acetylene On-Line Monitoring Technology Based on Laser Absorption Spectrum

中国科学院环境光学与技术重点实验室,安徽光学精密机械研究所,安徽合肥230031摘要乙炔作为有机化工产品原料,广泛应用于化学工业中,但易燃易爆,在储存和工业生产中有必要对其进行实时在线监测。可调谐半导体激光吸收光谱(TDLAS)技术具有高选择性、高灵敏、快速响应等特点,在痕量气体检测中得到了广泛的应用。文章研究了乙炔气体在近红外波段的吸收线分布特征,详细地讨论了基于近红外可调谐二极管激光吸收光谱技术的乙炔在线监测系统设计方案;建立了实验测量系统,研究了信号检测方法和浓度反演算法,对长度10cm的样品池和已知标准浓度乙炔气体配制的不同浓度乙炔气体进行检测,检测限可以达到1.46cm3.m-3;进行了动态检测实验,测量结果具有较好的稳定性和可靠性。分析表明系统设计方案可行,由此发展的乙炔在线监测系统可用于乙炔储存、运输和使用过程中泄漏报警。

As one of the materials in organic chemical industry, acetylene has been used in many aspects of chemical industry. But acetylene is a very dangerous inflammable and explosive gas, so it needs in-situ monitoring during industrial storage and production. Tunable diode laser absorption spectroscopy （TDLAS） technology has been widely used in atmospheric trace gases detection, because it has a lot of advantageous characteristics, such as high sensitivity, good selectivity, and rapid time response. The distribution characteristics of absorption lines of acetylene in near infrared band were studied, and then the system designing scheme of acetylene on line monitoring based on near infrared tunable diode laser absorption spectroscopy technology was discussed in detail. Moreover, the system of experiment measurement was set up and the method of signal detection and the algorithm of concentration inversion were studied. In addition, the sample cell with a path length of 10 cm, and the acetylene of different known concentrations were measured. As a result, the detection limit obtained reached 1.46 cm^3 · m^-3. Finally the dynamic detection experiment was carried out, and the measurement result is stable and reliable, so the design of the system is practicable through experiment analysis. On line acetylene leakage monitoring system was developed based on the experiment, and it is suitable for giving a leakage alarm of acetylene during its storage, transportation and use.