基于TDLAS直接吸收的CO_2浓度监测技术研究

Study on Monitoring Technology of Carbon Dioxide Concentration Based on TDLAS Direct Absorption

二氧化碳(CO_2)作为最主要的温室气体,能够引发许多气候变化和生态环境问题,因此需要监测大气环境中CO_2的浓度。根据可调谐半导体激光吸收原理,采用直接吸收的方法,在室温下扫描DFB激光器波长,得到CO_2在2 002nm附近的吸收光谱。同时根据Lambert-Beer定律反演出CO_2浓度,为了验证反演精度,选用LGR温室气体分析仪进行对比,两组数据绝对误差在2.5ppm左右,相关系数为0.986 4。长时间对比测量结果的绝对误差在9.8ppm左右,相关系数为0.933。TDLAS测量结果与LGR一致性较好,系统较稳定能够满足实验要求。该研究为仪器的小型化和室内CO_2的长时间测量提供了基础。

As the most important greenhouse gas.carbon dioxide （CO2） can lead to many problems of climate change and ecological environment. Therefore,it is necessary to monitor the concentration of CO2 in the atmosphere. Based on the tunable diode laser absorption principle, this paper used the method of direct absorption and scanned the wavelength of DFB laser at room temperature to obtain the CO2 absorption spectrum of 2002 nm. At the same time the CO, concentration was inverted according to Lambert Beer theorem. To verify the accuracy of the inversion, LGR greenhouse gas analyzer was used for comparison. The results show that the absolute error of the two sets of data is 2.5 ppm and the correlation coefficient is 0. 986 4. The absolute error of the measured result is about 9.8 ppm for a long time,and the correlation coefficient is 0. 933. The measurement results of TDLAS are consistent with LGR and the system is stable enough to meet the experimental requirements. This study provides the basis for the miniaturization of the instrurnent and the long-term measurement of indoor CO2.