基于NDIR的多组分危险气体在线监测系统设计

Design of multi-component dangerous gas online monitoring system based on NDIR

在冶金、石化、化工等工业领域生产过程中会产生大量易燃易爆、有毒有害的多组分危险气体(CO、CO_(2)、SO_(2)、NO、NH_(3)等),这些有害气体容易引发事故。而现有的在线测量预警系统不能满足高集成、低干扰、高灵敏的要求。本文针对影响检测结果的微弱信号、光源调制、气体信号交叉干扰、温度控制等因素,设计了相应的电路和算法,并进行了实验验证。实验结果表明,本文提出的基于锁相放大器电路的微弱信号提取技术、基于MOS管驱动电路的PWM波调制技术、基于融合算法的浓度反演模型,能够实现对五种危险气体(CO、CO_(2)、SO_(2)、NO、NH_(3))的在线监测,检出限达到0.01%,避免了多种气体之间的交叉干扰,适用于工业生产危险气体在线分析及预警系统,具有广阔的应用前景。

In the industrial production of metallurgy,petrochemical,chemical and other fields,a large amount of flammable,explosive,toxic and harmful multi-component hazardous gases(such as CO,CO2,SO2,NO,NH3,etc.)are generated,which can cause accidents.However,the existing online monitoring and warning systems cannot meet the requirements of high integration,low interference and high sensitivity.This paper designs corresponding cir-cuits and algorithms for the factors that affect the detection results,such as weak signal,light source modulation,gas signal cross interference,temperature control,etc.,and conducts experimental verification.The experimental results show that the weak signal extraction technology based on the lock-in amplifier circuit,the PWM wave modulation tech-nology based on the MOS tube driving circuit,and the concentration inversion model based on the fusion algorithm pro-posed in this paper can realize the online monitoring of five kinds of hazardous gases(CO,CO2,SO2,NO,NH3),with a detection limit of 0.01%,avoid the cross interference between various gases,and are suitable for the online a-nalysis and warning system of hazardous gases in industrial production,which have a broad application prospect.