CN118794891A - A device and method for detecting trace hydrogen concentration - Google Patents
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- 239000001257 hydrogen Substances 0.000 title claims abstract description 74
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 74
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 73
- 238000000034 method Methods 0.000 title claims description 10
- 238000001514 detection method Methods 0.000 claims abstract description 32
- 238000006243 chemical reaction Methods 0.000 claims abstract description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 25
- 230000003287 optical effect Effects 0.000 claims abstract description 21
- 239000003054 catalyst Substances 0.000 claims abstract description 10
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 9
- 230000003647 oxidation Effects 0.000 claims abstract description 8
- 150000002431 hydrogen Chemical class 0.000 claims abstract description 5
- 239000007789 gas Substances 0.000 claims description 45
- 238000010521 absorption reaction Methods 0.000 claims description 7
- 238000005070 sampling Methods 0.000 claims description 7
- 239000002274 desiccant Substances 0.000 claims description 5
- 239000010453 quartz Substances 0.000 description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 7
- 238000010586 diagram Methods 0.000 description 4
- 238000004867 photoacoustic spectroscopy Methods 0.000 description 4
- 230000001105 regulatory effect Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 230000003197 catalytic effect Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
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- 101000827703 Homo sapiens Polyphosphoinositide phosphatase Proteins 0.000 description 2
- 102100023591 Polyphosphoinositide phosphatase Human genes 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000007084 catalytic combustion reaction Methods 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
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Abstract
Description
技术领域Technical Field
本发明涉及一种痕量氢气浓度检测装置及方法，属于物质浓度检测技术领域。The invention relates to a device and method for detecting trace hydrogen concentration, belonging to the technical field of substance concentration detection.
背景技术Background Art
氢气传感器主要为电化学式和催化燃烧式两大类别。由于检测原理限制，现有的氢气传感器在痕量氢气监测方面存在显著不足，其精度难以达到ppb级别的要求。当氢气浓度较低时，氧化燃烧释放的热量较少，导致催化燃烧传感器无法正常感知，灵敏度较低。电化学式氢气传感器测量精度在ppm级别。同时由于氢气是一种对称双原子气体，对红外光谱无吸收特性，使得传统光学传感器在氢气检测方面存在困难。Hydrogen sensors are mainly divided into two categories: electrochemical and catalytic combustion. Due to the limitations of the detection principle, existing hydrogen sensors have significant deficiencies in trace hydrogen monitoring, and their accuracy is difficult to meet the requirements of the ppb level. When the hydrogen concentration is low, the heat released by oxidative combustion is less, resulting in the catalytic combustion sensor being unable to sense normally and having low sensitivity. The measurement accuracy of electrochemical hydrogen sensors is at the ppm level. At the same time, because hydrogen is a symmetrical diatomic gas with no absorption characteristics for the infrared spectrum, traditional optical sensors have difficulties in hydrogen detection.
光声光谱技术是目前对气体进行痕量浓度检测的重要方法之一。基于光声光谱技术的氢致光声频移技术利用氢气浓度对光声池谐振频率的调制作用，使用了其它强吸收谱线的气体作为泵浦气为系统提供声压，实现对氢气浓度的检测。但该技术的检测精度仍为ppm级，未达到ppb级痕量氢气浓度检测的要求。Photoacoustic spectroscopy is one of the important methods for detecting trace concentrations of gases. The hydrogen-induced photoacoustic frequency shift technology based on photoacoustic spectroscopy uses the modulation effect of hydrogen concentration on the resonant frequency of the photoacoustic cell, and uses other gases with strong absorption lines as pump gases to provide sound pressure for the system to detect hydrogen concentration. However, the detection accuracy of this technology is still at the ppm level, which does not meet the requirements for ppb-level trace hydrogen concentration detection.
发明内容Summary of the invention
针对上述现有技术缺陷，本发明的任务在于提供一种痕量氢气浓度检测装置及方法，实现ppb级痕量氢气浓度检测。In view of the above-mentioned defects in the prior art, the task of the present invention is to provide a device and method for detecting trace hydrogen concentration to achieve ppb-level trace hydrogen concentration detection.
本发明技术方案如下：一种痕量氢气浓度检测装置，包括同光程双光路光源、第一光声池、第二光声池、第一声电转换单元、第二声电转换单元、差分运算放大器和输出模块，所述同光程双光路光源为所述第一光声池和第二光声池提供具有相同光程、波长、频率的第一准直光线和第二准直光线，所述第一准直光线和第二准直光线的波长与水分子的吸收波段对应，所述第一光声池和所述第二光声池之间设有导通通路，所述导通通路内设有催化剂，所述催化剂用于催化氢气氧化为水，所述第一光声池设有待测样品入口，所述第二光声池连接有取样泵，所述第一声电转换单元用于将所述第一光声池的谐振管振动信号转换为第一电压信号送入所述差分运算放大器，所述第二声电转换单元用于将所述第二光声池的谐振管振动信号转换为第二电压信号送入所述差分运算放大器，所述差分运算放大器用于输出第一电压信号和所述第二电压信号的差值，所述输出模块用于根据所述差值依据电压与浓度对应线性关系输出浓度结果。The technical solution of the present invention is as follows: a trace hydrogen concentration detection device comprises a same-optical-path dual-light-path light source, a first photoacoustic cell, a second photoacoustic cell, a first acoustic-to-electric conversion unit, a second acoustic-to-electric conversion unit, a differential operational amplifier and an output module, wherein the same-optical-path dual-light-path light source provides the first photoacoustic cell and the second photoacoustic cell with a first collimated light and a second collimated light having the same optical path, wavelength and frequency, wherein the wavelengths of the first collimated light and the second collimated light correspond to the absorption band of water molecules, a conduction path is provided between the first photoacoustic cell and the second photoacoustic cell, a catalyst is provided in the conduction path, and the catalyst is used The method is to catalyze the oxidation of hydrogen into water, wherein the first photoacoustic cell is provided with an inlet for a sample to be tested, the second photoacoustic cell is connected with a sampling pump, the first acoustic-to-electric conversion unit is used to convert the vibration signal of the resonance tube of the first photoacoustic cell into a first voltage signal and send it into the differential operational amplifier, the second acoustic-to-electric conversion unit is used to convert the vibration signal of the resonance tube of the second photoacoustic cell into a second voltage signal and send it into the differential operational amplifier, the differential operational amplifier is used to output the difference between the first voltage signal and the second voltage signal, and the output module is used to output the concentration result according to the difference according to the corresponding linear relationship between voltage and concentration.
进一步地，所述第一准直光线和第二准直光线的波长为1450～1950nm。Furthermore, the wavelengths of the first collimated light and the second collimated light are 1450-1950 nm.
进一步地，为了方便确认第一准直光线和第二准直光线符合相同光程、波长、频率的要求，所述第一光声池和所述第二光声池在第一准直光线和第二准直光线入射的相对端设有光电转换单元。Furthermore, in order to facilitate confirmation that the first collimated light and the second collimated light meet the requirements of the same optical path, wavelength and frequency, the first photoacoustic cell and the second photoacoustic cell are provided with photoelectric conversion units at the opposite ends where the first collimated light and the second collimated light are incident.
进一步地，所述导通通路设有由所述第一光声池向所述第二光声池单向导通的单向阀，避免第二光声池内水蒸气的回流。Furthermore, the conduction passage is provided with a one-way valve for one-way conduction from the first photoacoustic cell to the second photoacoustic cell, so as to prevent the backflow of water vapor in the second photoacoustic cell.
进一步地，所述待测样品入口设有蜂窝干燥剂。通过蜂窝干燥剂去除待测样品的水蒸气并进行稳流。Furthermore, a honeycomb desiccant is provided at the inlet of the sample to be tested, and water vapor of the sample to be tested is removed by the honeycomb desiccant and a steady flow is performed.
进一步地，所述第一光声池和所述第二光声池设置在光声池腔室，所述光声池腔室内设有加热器。通过加热器加热保持第一光声池和第二光声池所处的环境温度，防止水蒸气冷凝。Furthermore, the first photoacoustic cell and the second photoacoustic cell are arranged in a photoacoustic cell chamber, and a heater is arranged in the photoacoustic cell chamber to maintain the ambient temperature of the first photoacoustic cell and the second photoacoustic cell by heating with the heater to prevent condensation of water vapor.
进一步地，包括标定装置，所述标定装置包括氢气气源、空气气源、气体混合器、减压阀和针阀，所述氢气气源和空气气源连接至所述气体混合器的入口，所述气体混合器的出口连接至减压阀，所述减压阀的出口连接至所述针阀，所述针阀的出口连接至所述待测样品入口。Furthermore, it includes a calibration device, which includes a hydrogen gas source, an air gas source, a gas mixer, a pressure reducing valve and a needle valve, the hydrogen gas source and the air gas source are connected to the inlet of the gas mixer, the outlet of the gas mixer is connected to the pressure reducing valve, the outlet of the pressure reducing valve is connected to the needle valve, and the outlet of the needle valve is connected to the inlet of the sample to be tested.
进一步地，所述气体混合器的出口与所述减压阀之间设有气体缓冲器。Furthermore, a gas buffer is provided between the outlet of the gas mixer and the pressure reducing valve.
本发明的另一技术方案是，一种痕量氢气浓度检测方法，基于前述的痕量氢气浓度检测进行，所述检测方法包括步骤：由取样泵工作将待测样品从待测样品入口抽入第一光声池并依次经过导通通路和第二光声池，同光程双光路光源向第一光声池和第二光声池射入第一准直光线和第二准直光线，差分运算放大器输出由第一声电转换单元和第二声电转换单元得到的第一电压信号和所述第二电压信号的差值，所述输出模块根据所述差值依据电压与浓度对应线性关系输出浓度结果。Another technical solution of the present invention is a method for detecting trace hydrogen concentration, which is based on the aforementioned trace hydrogen concentration detection. The detection method includes the following steps: a sampling pump operates to draw the sample to be tested from the sample inlet into the first photoacoustic cell and passes through the conduction path and the second photoacoustic cell in sequence, a dual-light path light source with the same optical path emits a first collimated light beam and a second collimated light beam into the first photoacoustic cell and the second photoacoustic cell, a differential operational amplifier outputs the difference between the first voltage signal obtained by the first acoustic-to-electric conversion unit and the second acoustic-to-electric conversion unit and the second voltage signal, and the output module outputs the concentration result according to the difference based on the corresponding linear relationship between voltage and concentration.
进一步地，所述检测方法包括标定步骤，所述标定步骤为：将氢气与空气按设定比例混合得到多个不同氢气浓度的预混标准样品，预混标准样品从待测样品入口进入第一光声池并依次经过导通通路和第二光声池，同光程双光路光源向第一光声池和第二光声池射入第一准直光线和第二准直光线，差分运算放大器输出由第一声电转换单元和第二声电转换单元得到的第一电压信号和所述第二电压信号的差值得到电压与浓度对应线性关系。Furthermore, the detection method includes a calibration step, which is: mixing hydrogen and air in a set ratio to obtain a plurality of premixed standard samples with different hydrogen concentrations, the premixed standard samples enter the first photoacoustic cell from the sample inlet to be tested and pass through the conduction path and the second photoacoustic cell in sequence, a dual-light path light source with the same optical path emits a first collimated light and a second collimated light into the first photoacoustic cell and the second photoacoustic cell, and a differential operational amplifier outputs a first voltage signal obtained by the first acoustic-to-electric conversion unit and the second acoustic-to-electric conversion unit and obtains a linear relationship between voltage and concentration.
本发明与现有技术相比的优点在于：The advantages of the present invention compared with the prior art are:
通过设计的双通路光声池，将痕量氢气催化氧化为水蒸气，利用光声光谱技术对痕量水蒸气进行检测，进而计算出对应的氢气浓度，同光程双光路的设计策略，并通过电压信号的差分运算进行处理，确保了输出电信号与待测氢气浓度之间呈现出优异的线性关系，显著提升了测量结果的准确性和可靠性，实现了ppb级痕量氢气浓度检测。Through the designed dual-path photoacoustic cell, trace hydrogen is catalytically oxidized into water vapor, and the trace water vapor is detected using photoacoustic spectroscopy to calculate the corresponding hydrogen concentration. The design strategy of dual optical paths with the same optical path and the differential operation of the voltage signal ensure that there is an excellent linear relationship between the output electrical signal and the hydrogen concentration to be measured, which significantly improves the accuracy and reliability of the measurement results and realizes the detection of trace hydrogen concentration at the ppb level.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
图1为痕量氢气浓度检测装置的结构示意图。FIG1 is a schematic structural diagram of a device for detecting trace hydrogen concentration.
图2为痕量氢气浓度检测装置的标定装置的结构示意图。FIG. 2 is a schematic structural diagram of a calibration device for a trace hydrogen concentration detection device.
图3为痕量氢气浓度检测的原理示意图。FIG3 is a schematic diagram showing the principle of trace hydrogen concentration detection.
图4为拟合的电压与浓度对应线性关系图。FIG4 is a fitted linear relationship diagram of voltage and concentration.
具体实施方式DETAILED DESCRIPTION
下面结合实施例对本发明作进一步说明，但不作为对本发明的限定。The present invention will be further described below in conjunction with the embodiments, but are not intended to limit the present invention.
请结合图1至图3所示，本发明的痕量氢气浓度检测装置包括同光程双光路光源、第一光声池1、第二光声池2、第一声电转换单元3、第二声电转换单元4、差分运算放大器5和输出模块6，同光程双光路光源为第一光声池1和第二光声池2提供具有相同光程、波长、频率的第一准直光线7和第二准直光线8。为了保证第一准直光线7和第二准直光线8的一致性，同光程双光路光源包括激光驱动器9、激光二极管10、分束镜11、第一反射镜12、第二反射镜13、第三反射镜14和补偿镜15，激光二极管10的激光波长选在1450 nm和1950 nm之间，此波长对应着水分子的吸收波段。分束镜11将光源分为两路，并确保其光程满足L4=L5。补偿镜15弥补分束镜11的光程差，配合对第二反射镜13和第三反射镜14的微调，改变L3大小使L3+ L7=L1+L2+L6，保证第一准直光线7和第二准直光线8具有相同光程。Please refer to Figures 1 to 3, the trace hydrogen concentration detection device of the present invention includes a same-optical-path dual-path light source, a first photoacoustic cell 1, a second photoacoustic cell 2, a first acoustic-to-electric conversion unit 3, a second acoustic-to-electric conversion unit 4, a differential operational amplifier 5 and an output module 6, and the same-optical-path dual-path light source provides the first photoacoustic cell 1 and the second photoacoustic cell 2 with a first collimated light 7 and a second collimated light 8 having the same optical path, wavelength and frequency. In order to ensure the consistency of the first collimated light 7 and the second collimated light 8, the same-optical-path dual-path light source includes a laser driver 9, a laser diode 10, a beam splitter 11, a first reflector 12, a second reflector 13, a third reflector 14 and a compensation mirror 15, and the laser wavelength of the laser diode 10 is selected between 1450 nm and 1950 nm, which corresponds to the absorption band of water molecules. The beam splitter 11 divides the light source into two paths and ensures that its optical path satisfies L4 = L5 . The compensating mirror 15 compensates for the optical path difference of the beam splitter 11 and cooperates with the fine adjustment of the second reflector 13 and the third reflector 14 to change the size of L3 so that L3 + L7 = L1 +L2 + L6 , ensuring that the first collimated light 7 and the second collimated light 8 have the same optical path.
同光程双光路光源设置在光路腔室16中，紧邻光路腔室16设置光声池腔室17，光路腔室16与光声池腔室17通过保温阻燃材料18阻隔。具有相同内部结构的第一光声池1和第二光声池2平行设置在光声池腔室17中。第一光声池1和第二光声池2的第一端设置谐振管，第一光声池1和第二光声池2的第一端之间通过导通通路19连通，导通通路19设有由第一光声池1向第二光声池2单向导通的单向阀以及蜂窝氧化催化剂20，该催化剂材料为铂丝等。这类氧化催化剂可以保证在常温下对微量可燃气体进行催发氧化反应，则微量氢气与氧气催化氧化生成水蒸气。The same optical path double light path light source is arranged in the light path chamber 16, and the photoacoustic cell chamber 17 is arranged adjacent to the light path chamber 16, and the light path chamber 16 and the photoacoustic cell chamber 17 are blocked by the heat-insulating flame-retardant material 18. The first photoacoustic cell 1 and the second photoacoustic cell 2 with the same internal structure are arranged in parallel in the photoacoustic cell chamber 17. The first end of the first photoacoustic cell 1 and the second photoacoustic cell 2 is provided with a resonance tube, and the first end of the first photoacoustic cell 1 and the second photoacoustic cell 2 are connected through a conducting passage 19, and the conducting passage 19 is provided with a one-way valve for unidirectional conduction from the first photoacoustic cell 1 to the second photoacoustic cell 2 and a honeycomb oxidation catalyst 20, and the catalyst material is platinum wire or the like. This type of oxidation catalyst can ensure that the trace combustible gas is catalyzed to oxidize at room temperature, and the trace hydrogen and oxygen are catalytically oxidized to generate water vapor.
第一光声池1内设置第一声电转换单元3用于将第一光声池1的谐振管振动信号转换为第一电压信号，第二光声池2内设置第二声电转换单元4用于将第二光声池的谐振管振动信号转换为第二电压信号。本实施例中第一声电转换单元3和第二声电转换单元4的声波采集的部分为石英音叉。第一光声池1的第二端设置待测样品入口21，待测样品入口21设有蜂窝干燥剂22，该蜂窝干燥剂22为活性炭用于去除气体样品中的水蒸气并稳定流入第一光声池1的气流。第二光声池3的第二端通过缓冲室23连接取样泵24。A first acoustic-to-electric conversion unit 3 is provided in the first photoacoustic cell 1 to convert the resonance tube vibration signal of the first photoacoustic cell 1 into a first voltage signal, and a second acoustic-to-electric conversion unit 4 is provided in the second photoacoustic cell 2 to convert the resonance tube vibration signal of the second photoacoustic cell into a second voltage signal. In this embodiment, the sound wave collecting parts of the first acoustic-to-electric conversion unit 3 and the second acoustic-to-electric conversion unit 4 are quartz tuning forks. A sample inlet 21 to be tested is provided at the second end of the first photoacoustic cell 1, and a honeycomb desiccant 22 is provided at the sample inlet 21 to be tested. The honeycomb desiccant 22 is activated carbon used to remove water vapor in the gas sample and stabilize the airflow flowing into the first photoacoustic cell 1. The second end of the second photoacoustic cell 3 is connected to a sampling pump 24 through a buffer chamber 23.
第一光声池1的第二端还设置第一光敏传感器25用于接收经过第一光声池1的谐振管后的第一准直光线7，第二光声池2的第二端还设置第二光敏传感器26用于接收经过第二光声池2的谐振管后的第二准直光线8，通过第一光敏传感器25和第二光敏传感器26测得的信号进行光路的校准。A first photosensor 25 is also provided at the second end of the first photoacoustic cell 1 for receiving the first collimated light 7 after passing through the resonance tube of the first photoacoustic cell 1. A second photosensor 26 is also provided at the second end of the second photoacoustic cell 2 for receiving the second collimated light 8 after passing through the resonance tube of the second photoacoustic cell 2. The optical path is calibrated by the signals measured by the first photosensor 25 and the second photosensor 26.
在催化氧化反应过程中，痕量氢气经过转化，生成略高于室温的水蒸气，这些水蒸气直接进入第二光声池2，则会部分冷凝成水滴。为了避免这一现象，采用电热丝27对光声池腔室17进行加热处理。光声池腔室17设置热电偶28进行温度检测以控制电热丝的工作状态，确保光声池腔室17温度稳定在45℃至50℃的范围内，可以有效预防水蒸气冷凝现象的发生。因受热后光声池腔室17内气体将发生膨胀现象，为确保系统稳定运行，在光声池腔室17的一侧设计一处微小的气孔29。During the catalytic oxidation reaction, trace amounts of hydrogen are converted to generate water vapor slightly above room temperature. These water vapors directly enter the second photoacoustic cell 2 and are partially condensed into water droplets. In order to avoid this phenomenon, the photoacoustic cell chamber 17 is heated by a heating wire 27. The photoacoustic cell chamber 17 is provided with a thermocouple 28 for temperature detection to control the working state of the heating wire, ensuring that the temperature of the photoacoustic cell chamber 17 is stable within the range of 45°C to 50°C, which can effectively prevent the occurrence of water vapor condensation. Because the gas in the photoacoustic cell chamber 17 will expand after being heated, a tiny air hole 29 is designed on one side of the photoacoustic cell chamber 17 to ensure the stable operation of the system.
差分运算放大器5和输出模块6为信号处理单元，由差分运算放大器5接收第一电压信号和第二电压信号输出两者的差值，输出模块6用于根据差值依据标定后得到的电压与浓度对应线性关系输出浓度结果。The differential operational amplifier 5 and the output module 6 are signal processing units. The differential operational amplifier 5 receives the first voltage signal and the second voltage signal and outputs the difference between the two. The output module 6 is used to output the concentration result according to the linear relationship between the voltage and the concentration obtained after calibration based on the difference.
标定时，通过标定装置向待测样品入口提供确定氢气浓度的预混标准样品。标定装置包括氢气气源30、空气气源31、气体混合器32、气体缓冲器33、减压阀34和针阀35，氢气气源30通过第一调节阀36、第一质量流量计37后连接至气体混合器32，空气气源31通过第二调节阀38、第二质量流量计39后连接至气体混合器32。气体混合器32的出口连接至气体缓冲器33，气体缓冲器33的出口连接减压阀34，减压阀34的出口通过压力表40连接至针阀35，针阀35的出口连接至待测样品入口21。During calibration, a premixed standard sample for determining the hydrogen concentration is provided to the inlet of the sample to be tested through the calibration device. The calibration device includes a hydrogen source 30, an air source 31, a gas mixer 32, a gas buffer 33, a pressure reducing valve 34 and a needle valve 35. The hydrogen source 30 is connected to the gas mixer 32 through a first regulating valve 36 and a first mass flow meter 37, and the air source 31 is connected to the gas mixer 32 through a second regulating valve 38 and a second mass flow meter 39. The outlet of the gas mixer 32 is connected to the gas buffer 33, and the outlet of the gas buffer 33 is connected to the pressure reducing valve 34. The outlet of the pressure reducing valve 34 is connected to the needle valve 35 through a pressure gauge 40, and the outlet of the needle valve 35 is connected to the inlet 21 of the sample to be tested.
痕量氢气浓度检测装置进行检测的原理是：当第一准直光线7和第二准直光线8射入第一光声池1和第二光声池2内，水分子会吸收光能引发周期性膨胀，从而产生声波。微弱声波在谐振管作用下与石英音叉发生共振，将声信号转变为电压信号。通过对石英音叉电压信号的分析，可以获取相应的水蒸气浓度信息。根据石英音叉光声光谱原理，信号强度与气体吸收系数呈正比关系：The principle of the trace hydrogen concentration detection device is: when the first collimated light 7 and the second collimated light 8 are incident on the first photoacoustic cell 1 and the second photoacoustic cell 2, water molecules absorb light energy and cause periodic expansion, thereby generating sound waves. The weak sound waves resonate with the quartz tuning fork under the action of the resonance tube, converting the sound signal into a voltage signal. By analyzing the voltage signal of the quartz tuning fork, the corresponding water vapor concentration information can be obtained. According to the principle of quartz tuning fork photoacoustic spectroscopy, the signal intensity is proportional to the gas absorption coefficient:
（1） (1)
δ为常数，S为信号强度，α为吸收系数，P为激光功率，Q为石英音叉品质因子，f 0为石英音叉共振频。第一光声池1的作用主要是用于测量干燥后气体中残余的水蒸气，样品气体中氢气通过蜂窝氧化催化剂22后与氧气催化氧化生成水蒸气，第二光声池2的作用主要是用于测量进入第一光声池1的干燥后气体中残余的水蒸气以及经过催化氧化后生成的水蒸气的总量。 δ is a constant, S is the signal intensity, α is the absorption coefficient, P is the laser power, Q is the quartz tuning fork quality factor, and f0 is the quartz tuning fork resonance frequency. The first photoacoustic cell 1 is mainly used to measure the residual water vapor in the dried gas. The hydrogen in the sample gas is catalytically oxidized with oxygen to generate water vapor after passing through the honeycomb oxidation catalyst 22. The second photoacoustic cell 2 is mainly used to measure the residual water vapor in the dried gas entering the first photoacoustic cell 1 and the total amount of water vapor generated after catalytic oxidation.
第一光声池1中残留微量水蒸气浓度与信号强度成正比，此时第一声电转换单元3输出信号强度为S 1 。第二光声池2的第二声电转换单元4输出电压信号强度为S 2。经过差分运算放大器5处理，输出信号S t 即为S 2与S 1的差值，即The residual trace water vapor concentration in the first photoacoustic cell 1 is proportional to the signal intensity. At this time, the output signal intensity of the first acoustic-to-electric conversion unit 3 is S 1 . The output voltage signal intensity of the second acoustic-to-electric conversion unit 4 of the second photoacoustic cell 2 is S 2 . After being processed by the differential operational amplifier 5 , the output signal St is the difference between S 2 and S 1 , that is
S t = S 2 - S 1 （2） S t = S 2 - S 1 （2）
由式（1）可知，石英音叉输出的电压信号与直接测得的气体浓度之间呈现出线性关系。经过差分运算处理后的电压信号S t ，其与催化氧化过程中生成的水蒸气浓度之间亦形成明确的线性关联。痕量氢气在催化剂的作用下完全氧化为水蒸气，因此，电压信号S t 与氢气浓度之间亦呈现线性关系。通过配置标准浓度氢气并检测，将输出信号S t 与氢气浓度拟合，对应拟合结果即得到电压与浓度对应线性关系可用于对实际氢气浓度的准确且可靠的测量。It can be seen from formula (1) that there is a linear relationship between the voltage signal output by the quartz tuning fork and the directly measured gas concentration. The voltage signal St after differential operation also forms a clear linear correlation with the water vapor concentration generated during the catalytic oxidation process. Trace hydrogen is completely oxidized into water vapor under the action of the catalyst. Therefore, there is also a linear relationship between the voltage signal St and the hydrogen concentration. By configuring standard concentration hydrogen and testing, the output signal St is fitted with the hydrogen concentration. The corresponding fitting result, that is, the linear relationship between voltage and concentration, can be used to accurately and reliably measure the actual hydrogen concentration.
基于本实施例的痕量氢气浓度检测装置进行检测的方法是这样的：The method for detecting the trace hydrogen concentration detection device according to this embodiment is as follows:
首先进行光路校准。取样泵开始工作。首先检查第一光敏传感器25和第二光敏传感器26信号数值是否正常，如果第二光敏传感器26信号偏弱，则需要前后微调第三反射镜14。之后，观察电压信号S t 绝对值数值是否小于10-6 V。如果不是，则需要调整第二反光镜13和第三反光镜14。第二反光镜13和第三反光镜14始终保持平行。在电压信号数值大于0的情况下，需要减小第二光声池2对应的第二准直光线8光程大小。具体的操作步骤如下：逆时针微调第二反光镜13和第三反光镜14，同时沿着水平方向，将第三反射镜14向第二光声池2靠近的方向进行微调。反之，若电压信号的绝对值数值小于0，则应顺时针微调第二反光镜13和第三反光镜14，同时沿着水平方向，将第三反射镜14向第二光声池2远离的方向微调。First, perform optical path calibration . The sampling pump starts working. First, check whether the signal values of the first photosensor 25 and the second photosensor 26 are normal. If the signal of the second photosensor 26 is weak, the third reflector 14 needs to be fine-tuned forward and backward. Afterwards, observe whether the absolute value of the voltage signal St is less than 10-6 V. If not, the second reflector 13 and the third reflector 14 need to be adjusted. The second reflector 13 and the third reflector 14 always remain parallel. When the voltage signal value is greater than 0, it is necessary to reduce the optical path size of the second collimated light 8 corresponding to the second photoacoustic pool 2. The specific operating steps are as follows: fine-tune the second reflector 13 and the third reflector 14 counterclockwise, and at the same time, fine-tune the third reflector 14 in the direction close to the second photoacoustic pool 2 along the horizontal direction. On the contrary, if the absolute value of the voltage signal is less than 0, the second reflector 13 and the third reflector 14 should be fine-tuned clockwise, and at the same time, fine-tune the third reflector 14 in the direction away from the second photoacoustic pool 2 along the horizontal direction.
然后进行标定获得电压与浓度对应线性关系。采用空气泵对空气进行标准化采样获得空气气源31，氢气瓶提供的氢气为氢气气源30。由第一调节阀36、第一质量流量计37、第二调节阀38、第二质量流量计39控制空气和氢气流量，并导入气体混合器32进行均匀混合。最终，经过充分混合的气体被输送至气体缓冲器33，为后续实验或测试工作提供稳定且可靠的气体源。气体缓冲器33的压力范围控制在4~5 MPa之间，气体缓冲器33体积为1 m3。以配置100 ppb的H2气体样本为例：① 根据气体缓冲器33压力粗略推算气体摩尔数。假定气体缓冲器33压力以4.5 MPa，室温为298.15 K，由气体状态方程计算出对应气体摩尔数为1613.67 mol。② 根据粗算结果确定最终氢气和空气质量配比，氢气摩尔数取1.60×10-5 mol，氢气质量为0.000032g；空气摩尔数取1.60×10-5 mol，对应空气质量为4640g。③根据质量配置情况，控制进气，配置出100 ppb H2气体样本。Then, calibration is performed to obtain the linear relationship between voltage and concentration. An air pump is used to perform standardized sampling of air to obtain an air source 31, and the hydrogen provided by the hydrogen bottle is a hydrogen source 30. The air and hydrogen flow rates are controlled by the first regulating valve 36, the first mass flow meter 37, the second regulating valve 38, and the second mass flow meter 39, and are introduced into the gas mixer 32 for uniform mixing. Finally, the fully mixed gas is transported to the gas buffer 33 to provide a stable and reliable gas source for subsequent experiments or tests. The pressure range of the gas buffer 33 is controlled between 4 and 5 MPa, and the volume of the gas buffer 33 is 1 m 3 . Take the configuration of a 100 ppb H 2 gas sample as an example: ① Roughly estimate the number of gas moles based on the pressure of the gas buffer 33. Assuming that the pressure of the gas buffer 33 is 4.5 MPa and the room temperature is 298.15 K, the corresponding gas mole number calculated by the gas state equation is 1613.67 mol. ② According to the rough calculation results, the final hydrogen and air mass ratio is determined. The hydrogen mole is 1.60× 10-5 mol, and the hydrogen mass is 0.000032g; the air mole is 1.60× 10-5 mol, and the corresponding air mass is 4640g. ③ According to the mass configuration, control the air intake and configure a 100 ppb H2 gas sample.
在标定过程中，通过调节减压阀34，确保待测样品入口21压力稳定在0.15 MPa，以满足系统运行的稳定要求。通过对不同氢气混合气体样本测试，就可以得到电压与浓度对应线性关系，如图4所示。During the calibration process, the pressure at the inlet 21 of the sample to be tested is ensured to be stable at 0.15 MPa by adjusting the pressure reducing valve 34 to meet the stability requirements of the system operation. By testing different hydrogen mixed gas samples, the corresponding linear relationship between voltage and concentration can be obtained, as shown in FIG4 .
具体测试时，启动取样泵24，将待测样品从待测样品入口21抽入第一光声池1并依次经过导通通路19和第二光声池2，同光程双光路光源向第一光声池1和第二光声池2射入第一准直光线7和第二准直光线8，差分运算放大器5输出由第一声电转换单元3和第二声电转换单元4得到的第一电压信号和第二电压信号的差值，输出模块6根据差值依据电压与浓度对应线性关系输出浓度结果。为了验证痕量氢气浓度检测装置检测的可靠性，还是采用标定装置配置不同氢气浓度进行测量。下表记录了不同氢气检测结果与理论结果的对比数据，During the specific test, the sampling pump 24 is started, and the sample to be tested is pumped into the first photoacoustic cell 1 from the sample inlet 21 to be tested and passes through the conductive path 19 and the second photoacoustic cell 2 in sequence. The same optical path dual-path light source emits the first collimated light 7 and the second collimated light 8 into the first photoacoustic cell 1 and the second photoacoustic cell 2. The differential operational amplifier 5 outputs the difference between the first voltage signal and the second voltage signal obtained by the first acoustic-to-electric conversion unit 3 and the second acoustic-to-electric conversion unit 4. The output module 6 outputs the concentration result according to the linear relationship between the voltage and the concentration based on the difference. In order to verify the reliability of the detection of the trace hydrogen concentration detection device, a calibration device is used to configure different hydrogen concentrations for measurement. The following table records the comparison data of different hydrogen detection results and theoretical results.
上述结果进一步验证了本发明在痕量氢气检测方面的可靠性。The above results further verify the reliability of the present invention in detecting trace amounts of hydrogen.
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101002683A (en) * | 2007-01-12 | 2007-07-25 | 天津市先石光学技术有限公司 | Optical distance optional type atraumatic human body component measuring method, and apparatus therefor |
| CN105259116A (en) * | 2015-10-13 | 2016-01-20 | 安徽皖仪科技股份有限公司 | Trace gas measurement device and method with adoption of photo-acoustic spectroscopy |
| US20180024046A1 (en) * | 2015-02-02 | 2018-01-25 | Paj Sensor A/S | Photoacoustic sensor system and methodology for detecting target molecules |
| CN110907384A (en) * | 2019-12-10 | 2020-03-24 | 中国海洋大学 | Gas detection system based on Fourier domain optical coherent absorption spectrum technology and working method thereof |
| RU2761906C1 (en) * | 2020-12-25 | 2021-12-14 | Игорь Владимирович Шерстов | Resonant differential optical-acoustic detector |
| CN114965285A (en) * | 2022-05-11 | 2022-08-30 | 重庆邮电大学 | Photoacoustic spectrum detection system based on acoustic wave direct coupling-multi-optical-path photoacoustic cell |
| CN115201116A (en) * | 2022-09-15 | 2022-10-18 | 中国科学院合肥物质科学研究院 | Low-noise differential type Helmholtz photoacoustic spectrum detection device and method |
| CN116482033A (en) * | 2023-04-19 | 2023-07-25 | 哈尔滨工业大学 | A kind of differential photoacoustic spectroscopy gas detection device and method based on quartz tuning fork |
| WO2024045341A1 (en) * | 2022-09-01 | 2024-03-07 | 南方电网科学研究院有限责任公司 | Photoacoustic spectrometry-based gas testing apparatus |
-
2024
- 2024-09-14 CN CN202411288170.4A patent/CN118794891A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101002683A (en) * | 2007-01-12 | 2007-07-25 | 天津市先石光学技术有限公司 | Optical distance optional type atraumatic human body component measuring method, and apparatus therefor |
| US20180024046A1 (en) * | 2015-02-02 | 2018-01-25 | Paj Sensor A/S | Photoacoustic sensor system and methodology for detecting target molecules |
| CN105259116A (en) * | 2015-10-13 | 2016-01-20 | 安徽皖仪科技股份有限公司 | Trace gas measurement device and method with adoption of photo-acoustic spectroscopy |
| CN110907384A (en) * | 2019-12-10 | 2020-03-24 | 中国海洋大学 | Gas detection system based on Fourier domain optical coherent absorption spectrum technology and working method thereof |
| RU2761906C1 (en) * | 2020-12-25 | 2021-12-14 | Игорь Владимирович Шерстов | Resonant differential optical-acoustic detector |
| CN114965285A (en) * | 2022-05-11 | 2022-08-30 | 重庆邮电大学 | Photoacoustic spectrum detection system based on acoustic wave direct coupling-multi-optical-path photoacoustic cell |
| WO2024045341A1 (en) * | 2022-09-01 | 2024-03-07 | 南方电网科学研究院有限责任公司 | Photoacoustic spectrometry-based gas testing apparatus |
| CN115201116A (en) * | 2022-09-15 | 2022-10-18 | 中国科学院合肥物质科学研究院 | Low-noise differential type Helmholtz photoacoustic spectrum detection device and method |
| CN116482033A (en) * | 2023-04-19 | 2023-07-25 | 哈尔滨工业大学 | A kind of differential photoacoustic spectroscopy gas detection device and method based on quartz tuning fork |
Non-Patent Citations (2)
| Title |
|---|
| JIAHUI WU等: "Photoacoustic guided wavefront shaping using digital micromirror devices", OPTICS AND LASER TECHNOLOGY, 14 January 2024 (2024-01-14) * |
| JINGYI ZHU等: "Self-Fluence-Compensated Functional Photoacoustic Microscopy", IEEE TRANSACTIONS ON MEDICAL IMAGING, 31 December 2021 (2021-12-31) * |
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