气体组分检测

有效监测才能严格治理，看多组分气体监测仪如何应对环境空气污染！ 2020 China 挥发性有机物污染防治科技大会现场精彩回顾 挥发性有机物(VOCs)种类繁多，对人体健康和生态环境危害巨大，是较为复杂的一类污染物。VOCs China 2020是我国专注于VOCs污染防治领域的全产业链、供应链的专业展览会，最大范围荟萃国内外VOCs污染综合整治产业链上下游的先进技术、工艺、材料和装备等进行展示与合作。 天津润泽环保惊艳亮相展会现场，所携产品与解决方案备受瞩目，实现了信息技术与环保产业的深度融合。 01 监控污染明星产品 面对日益严重的环境空气污染问题，只有及时有效的实时监测污染情况，获得真实可信的数据，才可以为环境管理者提供制订管理措施的依据。 多组分气体监测仪：一款用于检测工业有毒有害气体的仪器，检测气体种类选择范围包括硫化氢、氨气、甲硫醚、甲硫醇、二甲二硫、二硫化碳、苯乙烯、氮氧化物、臭氧、二氧化硫、氯化氢、氯气、TVOC等工业气体，可以基于这些污染气体浓度分析出臭气浓度OU值。 用户也可根据实际应用需求定制气体种类、数量及检测范围等。相比较传统的化学法气体检测系统，本仪器具有检测速度快、检测灵敏度高、检测参数多并种类选择灵活、操作简便、系统维护量少等特点，逐步成为环境检测站、工业园区、大型化工制药企业等应对环境空气污染监测的必要的气体检测设备。 02 天津润泽环保技术团队 天津润泽环保科技有限公司依托总部雄厚的研发实力、注重科技投入、超前的思维、完善的管理机制， 以其从容、自信的姿态在行业中勇往前行。倾力打造国家信任、客户满意的企业形象。 通过本次展会，天津润泽环保迎来了很多老伙伴，更结识了很多新朋友，我们希望能把这份缘分持续下去，一起为中国环保产业做出贡献。感谢大家的关注！

近日，来自西安电子科技大学、哈尔滨工业大学可调谐（气体）激光技术国家级重点实验室的联合研究团队发表了《T型光声池的光声光谱技术用于基于三重共振模态的多组分气体的同时检测》论文。Recently, the joint research team from School of Optoelectronic Engineering, Xidian University, National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, published an academic papers T-type cell mediated photoacoustic spectroscopy for simultaneous detection of multi-component gases based on triple resonance modality 油浸式电力变压器是现代电力分配和传输系统中最重要的绝缘设备之一。通过同时测量绝缘油中的溶解气体，如一氧化碳（CO）、甲烷（CH4）和乙炔（C2H2），可以在电力变压器的过热、电弧和局部放电故障的早期诊断中提供合适的解决方案。变压器故障主要可分为过热故障和放电故障。CO、CH4和C2H2的含量变化是变压器故障的主要指标。过热故障包括裸金属过热、固体绝缘过热和低温过热。裸金属过热的特征是烃类气体（如CH4和C2H2）浓度的上升。上述两种气体的总和占总烃类气体的80%以上，其中CH4占较大比例（30 ppm）。CO的浓度（300 ppm）强烈指示固体绝缘过热和变压器故障中的低温过热。当变压器处于放电故障时，C2H2会急剧增加（5 ppm，占总烃类气体的20%-70%）。因此，本研究选择CO、CH4和C2H2作为目标分析物。传统的多组分气体定量检测方法，如气相色谱仪、半导体气体传感器和电化学传感器，在实时监测、恢复时间、选择性和交叉敏感性方面存在一定限制。基于光声光谱技术的光学传感器平台具有高灵敏度、高选择性、快速响应、长寿命和成熟的传感器设备等优点，在多组分气体传感领域发挥着重要作用。已经开发出多种基于光声光谱技术的多组分气体传感器模式，如傅里叶变换红外光声光谱模式、基于宽带检测的热辐射体或黑体辐射体使用多个带通滤波器、多激光器与时分复用（TDM）方法的结合，以及采用多共振器和频率分割复用（FDM）方案。然而，由于宽带光源的相对弱强度，弱光声（PA）信号易受到背景噪声的干扰，这是高灵敏度检测的主要障碍。Oil-immersed power transformer is one of the most important insulation equipment in modern power distribution and transmission systems. Simultaneous measurements of the dissolved gases in insulating oil, such as carbon monoxide (CO), methane (CH4) and acetylene (C2H2), can represent a suitable solution in early diagnosis of overheating, arcing and partial discharge failures of power transformers . Transformer fault can mainly be divided into overheating fault and discharge fault. The content changes of CO, CH4, and C2H2 are the main indicators of transformer failure. Overheating fault includes bare metal overheating, solid insulation overheating and low temperature overheating. The bare metal overheating is characterized by the rising concentration of hydrocarbon gas, such as CH4 and C2H2. The sum of the above two gases accounts for more than 80% of the total hydrocarbon gas, and CH4 accounts for a larger proportion (30 ppm). The concentration of CO (300 ppm) strongly indicates the solid insulation overheating and the low temperature overheating in the transformer failure. When the transformer is in discharge fault, the C2H2 will increase dramatically (5 ppm, 20%&minus 70% of the total hydrocarbon gas). Therefore, CO, CH4, and C2H2 are selected as the target analytes in this work. The traditional quantitative detection of multiple analytes, such as gas chromatographs, semiconductor gas sensors and electrochemical sensors, were limited in terms of real time monitoring, recovery time, poor selectivity and cross sensitivity. Photoacoustic spectroscopy (PAS)-based optical sensor platforms, which feature the advantages of high sensitivity, high selectivity, fast response, long lifetime and well-established sensing devices, have played an important role in the field of multi-component gas sensing. Various PAS-based multi-gas sensor modalities have been developed, such as Fourier transform infrared PAS modality, broadband detection based thermal emitters or blackbody radiators using several band-pass filters, the use of multi-lasers combined time-division multiplexing (TDM) methods , and multi-resonators with frequency-division multiplexing (FDM) schemes. Due to the relatively poor intensity of the broadband source, the weak photoacoustic (PA) signals were sensitively affected by the background noise, which was a major obstacle to highly sensitive detection. 由于吸收和共振圆柱体共同决定了其共振频率，设计并验证了一种T型光声池作为适当的传感器。通过引入激励光束位置优化，从模拟和实验中研究了三种指定的共振模式，呈现了可比较的振幅响应。使用QCL、ICL和DFB激光器作为激发光源，同时测量CO、CH4和C2H2，展示了多气体检测的能力。A T-type photoacoustic cell was designed and verified to be an appropriate sensor, due to the resonant frequencies of which are determined jointly by absorption and resonant cylinders. The three designated resonance modes were investigated from both simulation and experiments to present the comparable amplitude responses by introducing excitation beam position optimization. The capability of multi-gas detection was demonstrated by measuring CO, CH4 and C2H2 simultaneously using QCL, ICL and DFB lasers as excitation sources respectively.图片显示了配备了T型光声池的基于PAS的多组分气体传感器配置的示意图。使用三个激发激光器作为激光源，包括DFB ICL（HealthyPhoton，型号HPQCL-Q）、DFB QCL（HealthyPhoton，型号QC-Qube）和NIR激光二极管（NEL），分别在2968 cm&minus 1、2176.3 cm&minus 1和6578.6 cm&minus 1处发射，以实现对CH4、CO和C2H2的同时检测。ICL、QCL和NIR激光二极管在目标吸收波长处的光功率分别为8 mW、44 mW和32 mW，通过热功率计（Ophir Optronics 3 A）进行测量。所有激光源都通过调节电流和温度控制来驱动。A schematic diagram of PAS-based multi-component gas sensor configuration equipped with the developed T-type PAC is shown in Fig. Three excitation laser sources, including a DFB ICL (HealthyPhoton, model HPQCL-Q), a DFB QCL (HealthyPhoton, model QCQube) and an NIR laser diode (NEL) emitting at 2968 cm&minus 1, 2176.3 cm&minus 1 and 6578.6 cm&minus 1, were employed to realize the simultaneous detection of CH4, CO and C2H2. The optical powers of the ICL, QCL and NIR laser diode measured by a thermal power meter (Ophir Optronics 3 A) at the target absorption lines were 8 mW, 44 mW and 32 mW, respectively. All the laser sources were driven by tuning the current and temperature control.Fig. The schematic diagram of multi-resonance PAS-based gas sensor configuration equipped with the developed T-type PAC for multi-component gas simultaneous detection. Operating pressure: 760 Torr.HealthyPhoton, model HPQCL-QHealthyPhoton, model QCQube结论建立了基于T型光声池的多共振光声光谱气体传感器，并验证其能够进行多组分同时检测，达到ppb级别的灵敏度。通过有限元分析（FEA）模拟优化和实验光束激发位置设计，三个指定的谐振频率的光声响应相互比较，确保了同时检测多种微量气体的高性能。选择了CO、CH4和C2H2这三种可燃气体作为目标气体，使用QCL（4.59 µ m，44 mW）、ICL（3.37 µ m，8 mW）和NIR激光二极管（1.52 µ m，32 mW）作为入射光束进行同时检测验证。F1模式下，光束照射到缓冲腔体壁上，信噪比（SNR）相比通过吸收圆柱体的情况提高了4.5倍。实验得到了CO、CH4和C2H2的最小检测限（1σ）分别为89ppb、80ppb和664ppb，对应的归一化噪声等效吸收系数（NNEA）分别为5.75 × 10&minus 7 cm&minus 1 W Hz&minus 1/2、1.97 × 10&minus 8 cm&minus 1 W Hz&minus 1/2和4.23 × 10&minus 8 cm&minus 1 W Hz&minus 1/2。对湿度交叉敏感性进行改进的研究提供了对光声光谱传感器在湿度松弛相关效应方面的更好理解。利用单个光声腔体和单个探测器进行多组分气体传感的这种开发的光声光谱模式，具有在电力变压器故障的早期诊断方面的独特潜力。Conclusions A T-type cell based multi-resonance PAS gas sensor was established and verified to be capable of multi-component simultaneous ppb-level detection. By the FEA simulation optimization and experimental beam excitation position design, the PA responses of the three designated resonant frequencies are comparable which guarantees the high performance of multiple trace gas detection simultaneously. The three combustible species of CO, CH4 and C2H2 were selected as target gases for the simultaneous detection verification using a QCL (4.59 µ m, 44 mW), an ICL (3.37 µ m, 8 mW) and a NIR laser diode (1.52 µ m, 32 mW) as incident beams. The SNR for F1 mode with the beam irradiating on the buffer wall was increased by 4.5 times than that of passing through absorption cylinder. The experimental MDLs (1σ) were achieved as of 89ppb (CO), 80ppb (CH4) and 664ppb (C2H2) have been acquired, respectively, corresponding to the NNEA coefficients of5.75 × 10&minus 7 cm&minus 1 W Hz&minus 1/2, 1.97 × 10&minus 8 cm&minus 1 W Hz&minus 1/2 and 4.23 × 10&minus 8 cm&minus 1 W Hz&minus 1/2. An improved humidification investigation regarding cross-sensitivity analysis provides a better understanding of PAS sensors in humidity relaxation related effects. This developed PAS modality of utilizing a single PAC and a single detector for multicomponent gas sensing exhibits unique potential for early diagnosis of power transformer failures.Fig. 1. Simulated spectral distribution characteristics of CO, CH4 and C2H2 based on HITRAN Database. Temperature and pressure: 296 K and 1 atm respectively.Fig. 2. Schematic structure of the developed T-type PAC.Fig. 3. Simulated sound pressure distribution of T-type PAC model for the three selected resonance modes by FEA method. Color bar: Simulated sound pressure (Pa).Fig. 4. Simulation results of the T-type PAC acoustic characteristics with the incident beam position optimization. (a) and (b): Two different incident ways of the excitation beam (c), (d) and (e): The simulated pressure amplitude response vs. frequency for F1, F2 and F3 detection, respectively.Fig. 6. The experimental results of PA signals for different resonance modes by scanning the incident excitation beam. (a) Schematic diagram of the light source scanning process in the T-type PAC. Dashed line: Central axis. (b) The PA amplitude of 100 ppm CO vs. the beam position of ICL source. (c) The PA amplitude of 50 ppm CH4 vs. the beam position of ICL source. (d) The PA amplitude of 50 ppm C2H2 vs. the beam position of DFB laser diode. Insert: The irradiated surface of PAC.Fig. 7. The experimental results for CH4 detection with the incident beam position optimization. (a) Two different ways (I1, I2) of incident excitation beam using ICL for CH4 measurement (b) The PA amplitude vs. frequency of F1 for the two incident ways (c) The PA spectra of 100 ppm CH4 in the ICL tunning range using both incidence ways (d) The PA signal amplitude of CH4 vs. gas concentration for two incidence ways.Fig. 8. Noise level analysis of F1, F2 and F3 modes for two incidence ways.Fig. 9. Experimental frequency responses of the developed T-type PAC.Fig. 10. The PA signal amplitudes vs. laser modulation amplitudes for multi-component gas sensing. (a) The ICL modulation amplitudes for 100 ppm CH4 detection (b) The QCL modulation amplitudes for 400 ppm CO detection (c) The NIR laser diode modulation amplitudes for 100 ppm C2H2 detection.Fig. 11. The experimental results for simultaneous detection of multi-component gases. (a), (b) and (c): Measured 2f-PAS spectral scans of the CO, CH4 and C2H2 absorption features for F1, F2 and F3 modes, respectively.Fig. 12. Schematic of the improved humidification system for humidity control.引用：Le Zhang, Lixian Liu, Xueshi Zhang, Xukun Yin , Huiting Huan, Huanyu Liu, Xiaoming Zhao, Yufei Ma, Xiaopeng Shao,T-type cell mediated photoacoustic spectroscopy for simultaneous detection of multi-component gases based on triple resonance modality,Photoacoustics 31 (2023) 100492.https://doi.org/10.1016/j.pacs.2023.100492

3月17日，“智能传感器”重点专项“跨地域复杂油气管网安全高效运行状态监测传感系统及应用”课题“高精度多组分气体检测传感器研制”启动会在安光所召开，会议由张志荣研究员主持。 　　项目承担单位国家石油天然气管网集团有限公司陈朋超教授级高工、课题承担单位中科院合肥物质院张志荣研究员、课题参与单位国家石油天然气管网集团有限公司科学技术研究总院蔡永军副总监等相关科技人员20余人通过线上线下形式参加了交流会。 　　课题负责人张志荣研究员就承担的研究任务、总体目标、实施方案、研究队伍等进行了汇报。该课题主要针对油气管网微小泄漏感知能力不足、特殊场景传感器缺乏、区域站场泄漏逃逸不明晰等痛点及热点问题，以集成探头研发、激光吸收光谱技术、组网方式等研究内容为核心，建立两类型高性能传感系统，为构建管网传感器及系统综合试验平台，开发管网智能传感系统数字化应用平台，建立管网状态感知指标体系和传感器谱系提供技术支持，并在中俄和中缅油气管道的多个典型场景进行示范应用，为全面实现管网状态监测水平的提升和管道感知技术的自主可控贡献力量。 　　与会人员听取了汇报后，针对目标、任务和实施方案进行了深入且细致的讨论，充分肯定了实施方案的可行性，并针对涉及的中俄、中缅管道及站场的示范应用情况作了详细的讲解和分析，希望所研发的多类型传感器能够在多个场景形成突出的特色应用，解决现场亟需的技术难题，以切实行动贯彻习近平总书记“打造平安管道、绿色管道、发展管道、友谊管道”的重要指示要求。会后，与会人员还参观了超导托卡马克大科学装置。 　　“跨地域复杂油气管网安全高效运行状态监测传感系统及应用”项目，由国家石油天然气管网集团有限公司、中科院合肥物质院、哈尔滨工业大学、沈阳仪表科学研究院有限公司、机械工业仪器仪表综合技术经济研究所、国家管网集团西南管道有限责任公司、山东微感光电子有限公司、中科院金属研究所、中国石油大学(北京)、国家管网集团北方管道有限责任公司等优势研究机构联合承担。