基于红外吸收原理的甲烷浓度检测的实验研究

发布时间：2018-03-22 07:49

本文选题：甲烷气体　切入点：差分吸收法　出处：《燕山大学》2013年硕士论文　论文类型：学位论文

【摘要】：保证煤矿安全生产一直是我国能源产业的工作重点，然而瓦斯爆炸事故频发给国家造成了重大财产损失和严重威胁人民的生命安全。目前国内用于测定和标定瓦斯浓度的分析仪大多数实时性、稳定性和灵敏度等方面都有待提高，而国外一些大型厂家和研发机构在这方面已经有了相对成熟的产品，但是价格昂贵。基于甲烷气体对红外辐射的选择性吸收原理以及吸收强度是甲烷浓度的函数这一关系，进行了甲烷浓度检测系统的实验研究。通过分析和比较多种气体浓度检测方法，根据检测系统的测量要求和应用环境，选择红外吸收原理作为本检测系统的理论方法。比较白炽灯、发光二极管、半导体激光器的各项性能，，光源采用白炽灯IRL715，发出的光覆盖从可见光到5μm的波段。分析了探测器的性能指标，选用的是热释电探测器PYS3228，其内部集成了两个将红外辐射能量转化为电压信号的焦热电元件，在封装外壳开了两个窗口，在两个焦热电元件前分别装配了两个窄带滤光片，中心波长分别为3.31μm和4μm。根据所选光源和探测器的特点，设计了合理的光源调制电路和信号调理电路。采用STM32单片机作为检测仪的核心处理器，完成信号采集处理、浓度转换、声光报警等功能。以单片机为基础，设计了系统电源电路、光源调制电路、基本放大电路、锁相放大电路、显示电路以及声光报警电路，通过对单片机编程实现各模块的功能。当甲烷浓度超过预先设定的报警阈值时，产生声光报警信号。论文对检测系统进行了气体吸收实验，重复性实验和稳定性实验。结合实验数据给出了拟合曲线及误差分析，并进行了简单的标定，结果证明基于红外吸收原理的甲烷浓度检测系统具有一定的精度和良好的稳定性。
[Abstract]:Ensuring the safe production of coal mines has always been the focus of our country's energy industry. However, frequent gas explosion accidents have caused great property loss to the country and seriously threatened the lives of the people. At present, most of the domestic analyzer used to measure and calibrate the gas concentration need to be improved in the aspects of real-time, stability and sensitivity, etc. However, some large manufacturers and R & D institutions abroad have relatively mature products in this area, but the prices are expensive. Based on the principle of selective absorption of infrared radiation by methane gas and the relationship between absorption intensity and the function of methane concentration, The experimental study of methane concentration detection system was carried out. By analyzing and comparing many kinds of gas concentration detection methods, according to the measurement requirements and application environment of the detection system, the principle of infrared absorption is selected as the theoretical method of the detection system, and the incandescent lamps, light emitting diodes (LEDs) are compared. The various properties of semiconductor laser, the light source using incandescent lamp IRL715, the light from visible light to 5 渭 m band. The performance index of detector is analyzed. The Pyroelectric detector PYS3228 is composed of two pyroelectric elements which convert infrared radiation energy into voltage signals. Two windows are opened in the package shell, and two narrow band filters are assembled before the two pyroelectric elements. The central wavelength is 3.31 渭 m and 4 渭 m, respectively. According to the characteristics of the selected light source and detector, a reasonable light source modulation circuit and signal conditioning circuit are designed. The STM32 single chip microcomputer is used as the core processor of the detector to complete the signal acquisition and processing, and the concentration conversion. Based on single-chip microcomputer, the system power supply circuit, light source modulation circuit, basic amplifier circuit, phase-locked amplifier circuit, display circuit and acousto-optic alarm circuit are designed. The function of each module is realized by programming the single-chip microcomputer. When the methane concentration exceeds the preset alarm threshold, the acousto-optic alarm signal is generated. In this paper, gas absorption experiment, repeatability experiment and stability experiment are carried out, the fitting curve and error analysis are given according to the experimental data, and a simple calibration is carried out. The results show that the methane concentration detection system based on infrared absorption principle has certain accuracy and good stability.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP274;TD712.55

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