基于QCL-TDLAS的NH3浓度测量仿真研究

Simulation study of NH3 concentration measurement based on QCL-TDLAS

可调谐半导体激光吸收光谱(tunable diode laser absorption spectroscopy,TDLAS)作为一种新型气体浓度测量技术被广泛应用于NH_3浓度测量领域。利用Matlab可视化建模仿真软件Simulink分别实现了以中远红外量子级联激光器(quantum cascade laser,QCL)和近红外分布反馈式激光器(distributed feedback laser,DFB)做为光源的NH_3浓度TDLAS直接吸收测量仿真,并且分别在常温常压和烟气脱硝出口环境参数下理论分析了NH3浓度测量灵敏度、检测限和分辨率。仿真结果表明:与传统近红外DFB光源相比,QCL-TDLAS系统理论灵敏度高约50倍,检测限与分辨率可达ppb量级,痕量NH_3浓度测量能力得到大幅度提升。仿真过程和结果为QCL-TDLAS技术在NH_3浓度测量方面的研究提供了理论依据。

As a new gas concentration measurement technology,tunable diode laser absorption spectroscopy(TDLAS)is widely used in the field of NH3 concentration measurement.Using Matlab visual modeling and simulation software Simulink to realize the direct absorption measurement process simulation of NH3 concentration TDLAS with mid-and-far infrared quantum cascade laser(QCL)and near-infrared distributed feedback laser(DFB)as light source,under the environmental parameters of flue gas denitration and normal temperature and pressure respectively,the sensitivity,detection limit and resolution of NH3 concentration measurement were theoretically analyzed.The results show that theoretical sensitivity of the QCL-TDLAS system is about 50 times higher,compared with the traditional near-infrared DFB source.The detection limit and resolution can reach the ppb level,and the trace NH3 concentration measurement capability is greatly improved.The simulation process and results provide theoretical basis for QCL-TDLAS technology in NH3 concentration measurement.