温室气体光声光谱检测系统的建立及效果分析

Establishment and Effect Analysis of Greenhouse Gas Detection Based on Photoacoustic Spectroscopy Technology

“双碳”目标下,温室气体在线长期稳定监测技术是全面掌握温室气体排放及其环境、气候效应,并预测未来变化趋势的重要保障。为了实时在线监测工业生产现场等环境温室气体浓度及其变化趋势,及时采取相应措施,在分析光声光谱信号产生机理及多组分气体混合监测原理的基础上,根据温室气体的主要成分,分析其吸收光谱特性,基于光声光谱的多组分温室气体的定性和定量监测技术,搭建温室气体光声光谱在线监测实验平台,分析监测器内部噪声和环境温度、湿度等外部影响因素,并通过现场测试,分析试验数据,应用吸附法降低内外部因素的影响。结果表明,对称安装传声器和非共振式光声腔能有效削弱外部噪声对测试结果的影响;空气净化器能降低空气中水蒸气和其他气体对测试结果的影响;低、高浓度混合气体监测结果偏差均小于0.5,与GC测试结果偏差小于10%。应用光声光谱技术的环境温室气体监测技术监测范围宽,选择性好,且监测精度达10-6,适用于环境温室气体浓度在线监测。

Under the dual carbon target,the online long-term stability monitoring technology of greenhouse gases is an important guarantee for comprehensively mastering greenhouse gas emissions and their environmental and climate effects,and predicting future change trends.In order to monitor the concentration and change trend of greenhouse gases in industrial production sites and other environments in real time and online,and take corresponding measures in time,based on the analysis of the generation mechanism of photoacoustic spectral signals and the monitoring principle of multi-component gas mixture,the absorption spectral characteristics of greenhouse gases were analyzed according to the main components of greenhouse gases,and the qualitative and quantitative monitoring technology of multi-component greenhouse gases based on photoacoustic spectroscopy,an online monitoring experimental platform for greenhouse gas photoacoustic spectroscopy was set up to analyze the internal noise of the monitor,environmental temperature,humidity and other external influencing factors,and the test data was analyzed through on-site testing,and the impact of internal and external factors was reduced with adsorption method.The results showed that the symmetrical installation of microphone and non resonant optical acoustic cavity could effectively reduce the influence of external noise on the test results;The air purifier could reduce the influence of water vapor and other gases in the air on the test results;The deviation of low and high concentration mixed gas monitoring results was less than 0.5,and the deviation from GC test results was less than 10%.The environmental greenhouse gas monitoring technology using photoacoustic spectroscopy has wide monitoring range,good selectivity,and monitoring accuracy of 10-6,which is suitable for online monitoring of environmental greenhouse gas content.