基于QEPAS技术的乙炔微量气体高灵敏度检测研究

发布时间：2018-02-01 03:44

本文关键词： QEPAS C_H_气体共振频率微共振腔　出处：《光谱学与光谱分析》2017年09期 　论文类型：期刊论文

【摘要】：石英增强光声光谱(QEPAS)是近年来发展起来的一种痕量气体探测技术,具有系统体积小、价格低廉、探测灵敏度高等优点。乙炔(C_2H_2)是一种化学性质活泼的有毒气体,对它进行高灵敏度检测在变压器故障诊断、环境监测等领域有着重要的意义,基于此,采用QEPAS技术对C_2H_2微量气体展开高灵敏度检测研究。采用输出波长为1.53μm的连续波分布反馈半导体激光器作为激发光源。为了提高信噪比和简化数据处理过程,QEPAS传感器系统采用波长调制和2次谐波探测技术。为了提高QEPAS系统信号幅值,相比于常见的共振频率为32.768kHz的石英音叉,采用了共振频率较低的30.72kHz石英音叉作为声波传导器,同时还优化了石英音叉与激光束的空间位置、激光波长调制深度,并添加了声波微共振腔,选择的微共振腔长度为4mm、内径为0.5mm,最终获得了2.7ppm的优异检测极限,归一化噪声等效吸收系数为1.3×10~(-8) cm~(-1)·W·Hz~(-1/2)。
[Abstract]:Quartz enhanced photoacoustic spectroscopy (QEPAS) is a kind of trace gas detection technology developed in recent years, which has small system size and low price. Acetylene C2H2) is a kind of toxic gas with active chemical properties. It is of great significance in transformer fault diagnosis and environmental monitoring to detect it with high sensitivity. Based on this. The high sensitivity detection of C _ 2H _ 2 trace gas was studied by using QEPAS technique. The CW distributed feedback semiconductor laser with output wavelength of 1.53 渭 m was used as the excitation source. Noise ratio and simplified data processing process. The QEPAS sensor system adopts wavelength modulation and second harmonic detection technology. In order to improve the signal amplitude of QEPAS system, it is compared with the quartz tuning fork with a common resonance frequency of 32.768 kHz. The 30.72 kHz quartz tuning fork with low resonance frequency is used as the acoustic conduction device. The spatial position of the quartz tuning fork and laser beam, the laser wavelength modulation depth and the acoustic microresonator are also optimized. The length of the microresonator is 4 mm and the inner diameter is 0.5 mm. Finally, the excellent detection limit of 2.7 ppm is obtained. The equivalent absorption coefficient of normalized noise is 1.3 脳 10 ~ (-8) cm ~ (-1) 路W 路Hzn ~ (-1).
【作者单位】：哈尔滨工业大学可调谐(气体)激光技术重点实验室;哈尔滨工业大学动力工程及工程热物理博士后流动站;
【基金】：国家自然科学基金项目(61505041) 黑龙江省自然科学基金项目(F2015011) 中国博士后科学基金特别资助项目(2015T80350);中国博士后科学基金面上项目(2014M560262) 黑龙江省博士后科学基金项目(LBH-Z14074);黑龙江省博士后科学基金特别资助项目(LBH-TZ0602) 哈尔滨市科技创新人才专项资金项目(2016RAQXJ140) 中央高校基本科研业务费专项资金项目(HIT.NSRIF.2015044)资助
【分类号】：O657.3;TM407
【正文快照】： 引言乙炔(C2H2)是一种有毒气体,化学性质非常活泼、极易燃、具有爆炸等风险。C2H2是变压器绝缘油中的溶解气体之一,是表征电力变压器早期潜伏性故障的重要特征量[1],同时也是聚乙烯生产线上乙烯气流中的污染物之一[2]。因此,对C2H2气体浓度的高灵敏度、快速测量在变压器故障诊

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