空芯光纤多组分工业废气点源监测关键技术

The monitoring and rapid positioning of multi-component industrial exhaust with a large number of pollution point source or in case of accident emergency is still of great challenge. Spectral absorption has advantages of excellent reproducibility for quantitative analysis, long-time validity and strong anti-interference, which make it a candidate for gas pollution point source detection. However, it encounters the difficulties of: the poor sensitivity resulted from the limitation of its optical absorption path; the mismatch of the multi-component gas absorption peak and the light source wavelength resulting in its limited validity. To solve these problems, a hollow fiber gas chamber and a narrow-band tunable lasing is used in the project for the quantitative analysis of multi-component gas emission. Much attention will paid to: 1) Study on the filtering characteristics of Fabry-Perot filter, constructing a tunable fiber laser ring resonator, optimizing the coupling loss between a variety of fiber optic components, and realizing the tunable lasing output that covers a broad near infrared vibrational absorption band of a variety of industrial exhaust; 2) Study on the dependence of hollow fiber inner diameter and other parameters on the gas transport, diffusion performance, establishing the gas transport model theory within the hollow fiber, the design and optimization of hollow-core photonic crystal fiber gas chamber structure; 3) Study on the denoising processing of photoelectric signal and amplification skills of weak signal, building up the differential dual fiber optical system, and realizing the detecting signal output with a high signal-to-noise ratio, high stability and low noise. This study will be of great significance to the development of miniaturized monitoring equipments for multi-component industrial exhaust pollution with a high sensitivity.

多组分、突发性及大量工业废气污染点源监测与快速定位仍是个挑战。光谱吸收具有定量重复性好、时效性长与抗干扰性强等优点而成为点源检测的主要技术。但存在光程受限而导致精度不高，以及单波长光源不能匹配多组分气体特征吸收峰而使检测组分单一等问题。 针对上述问题，项目将采用空芯光纤作吸收气室，利用可调谐窄带激光对多组分气体进行光谱定量分析，拟重点开展：1)研究Fabry-Perot滤波特性，构建可调谐光纤激光环形谐振腔，优化多种光纤部件间的耦合损耗，获得涵盖多种工业废气近红外振动带，并具有高信噪比的可调谐激光输出；2)研究空芯光纤长度、内径等参数对气体输运、扩散性能的影响，建立空芯光纤内气体输运理论模型，设计与优化空芯光纤气室结构；3)研究光电信号去噪与弱信号放大相关技术，构建差分双光纤光路系统，获得高稳定性和低噪声的检测信号。本研究将为研发工业废气多组分、高灵敏、小型化点源监测设备提供技术参考。

多组分、突发性及大量工业废气污染点源监测与快速定位仍是个挑战。光谱吸收具有定量重复性好、时效性长与抗干扰性强等优点而成为点源检测的主要技术。但存在光程受限而导致精度不高，以及单波长光源不能匹配多组分气体特征吸收峰而使检测组分单一等问题。针对上述问题，项目采用空芯光纤作吸收气室，利用可调谐窄带激光对多组分气体进行光谱定量分析。.项目按照计划利用光纤耦合连接套实现多段空芯光子晶体光纤间低损耦合与传输，同时使空芯光纤内外气体可快速完成扩散；搭建窄带（线宽≤0.1nm）可含盖多种气体振动吸收峰的宽频谱可调谐激光光源，从而可对多组分工业废气进行联合检测，各自的吸收峰宽度均小于0.5nm，研究表明相互间干扰很小，通过后续的滤波处理完全可能去除，实现高选择性识别；构建近红外宽频谱范围可调谐光纤激光系统，利用长光程空芯光纤作气室，采用20μm芯径的HC-PCF作为气体吸收腔, 在光纤连接套管上留50μm缝隙作为气体进出口，气体在气体腔内的扩散时间小于2min，整个气室及连接部分的光传输损耗约为1.2dB，输出波长范围包括1550±50nm，最大输出功率达到2mW，线宽小于0.1nm，信噪比大于40dB。实现指标包括：.高精度检测：比现有水平显著提高检测精度1个数量级，检测限达到5ppm, 检测范围为10-10000ppm；.多组分检测：利用波长涵盖多种气体典型宽振动吸收带的调谐激光输出，满足混合多组分（C2H2、HCN、HI、CO2、NH3、H2S）独立定量分析要求；.快速现场检测：利用空芯光纤小型化结构设计满足便携式现场检测或在线监测需求，单次检测时间小于2min，多次重复响应小于10min；.发表SCI、EI 等基金标注的重要学术期刊论文9篇，申请专利9 项,完成相关软件著作权登记13项；联合培养相关领域博士研究生2人，硕士研究生4人。