Analyzer and method for online detection of trace neon in high-purity helium and ultra-pure helium

Abstract

An analyzer and method for on-line detection of trace neon in high-purity helium and ultra-pure helium, the analyzer comprises: a first switch valve, a purification device, a plasma emission detector, a signal acquisition system, a display device and a second switch valve, the first switch valve is used for controlling gas supplied to the purification device, the purification device is used for removing impurities except inert gas, and the plasma emission detector is used for detecting the trace neon in the high-purity helium and ultra-pure helium. The plasma emission detector uses an optical filter which allows light of 585 nanometers, 632 nanometers and 640 nanometers of characteristic peaks of a neon plasma emission spectrum to pass through, the second switch valve is connected with the plasma emission detector and used for controlling gas exhausted from the plasma emission detector, and the signal acquisition system is used for acquiring signals from the plasma emission detector. The display device is used for displaying analysis results of the signals. Therefore, carrier gas and a chromatographic column do not need to be used for separating gas impurities, the real concentration of neon in the sample gas can be directly reflected, the detection limit can reach 10 ppb or below, and the sensitivity is high.

Description

Technical Field

[0001] This invention relates to gas impurity analysis technology, and more specifically to an analyzer and method for online detection of trace amounts of neon in high-purity helium and ultrapure helium. Background Technology

[0002] Currently, the primary analytical method for analyzing impurities in high-purity helium is gas chromatography (GC). However, there are two major technical challenges in detecting neon in helium using GC: insufficient sensitivity and susceptibility to interference from neon in the carrier gas. When analyzing neon in helium using a chromatograph equipped with a helium ionization detector, the low metastable energy of helium results in a low ionization rate for neon, leading to a detection sensitivity of approximately 0.1 ppm, which is insufficient. Furthermore, since GC is a relative method, typically using the carrier gas as the relative zero point, and neon in the carrier gas cannot be removed by conventional methods, it can mask the signal of neon in the sample gas. Therefore, the neon content in the carrier gas affects the accuracy of the neon content in the sample gas, and sometimes it may even completely fail to detect neon in the sample gas. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide an analyzer and method for online detection of trace amounts of neon in high-purity helium and ultrapure helium.

[0004] According to one aspect of the present invention, an online analyzer for detecting trace amounts of neon in high-purity helium and ultrapure helium is provided, comprising: a first switching valve, a purification device, a plasma emission detector, a signal acquisition system, a display device, and a second switching valve, wherein the first switching valve is used to control the gas supplied to the purification device, the purification device is used to remove impurities other than inert gases, the plasma emission detector uses a filter that allows light with the characteristic peaks of the neon plasma emission spectrum at 585 nm, 632 nm, and 640 nm to pass through, the second switching valve is connected to the plasma emission detector and is used to control the gas discharged from the plasma emission detector, the signal acquisition system is used to acquire signals from the plasma emission detector, and the display device is used to display the analysis results of the signals.

[0005] Preferably, the purification device is a zirconium vanadium iron bipolar purifier, used to remove impurities from helium gas.

[0006] Preferably, the plasma emission detector can use helium gas generated by the evaporation of liquid helium as the zero-point gas for zero-point calibration.

[0007] According to another aspect of the present invention, a method for online detection of trace neon in high-purity helium and ultra-pure helium is provided, characterized in that the method uses the above-mentioned online analyzer for detecting trace neon in high-purity helium and ultra-pure helium, and includes the following steps:

[0008] S2, System preparation: Stabilize the purification device to the working temperature under protective gas purging, wherein the first electrode of the purification device is 350 degrees Celsius, the second electrode is 200 degrees Celsius, the protective gas is 5N high-purity helium, connect the high-purity helium to the inlet of the first switch valve, open the first switch valve and the second switch valve, turn on the analyzer to purge for the first predetermined time, and then turn on the purification device to continue purging for the second predetermined time.

[0009] S3, System Calibration: Includes zero-point calibration and range point calibration, wherein...

[0010] Zero-point calibration: The analyzer uses 6N helium gas, packaged via liquid helium evaporation, as the zero-point gas. This gas is introduced into the analyzer for analysis to calibrate the analyzer's zero point.

[0011] Range calibration: Use a helium standard gas containing 10 ppm neon to calibrate the analyzer's range by passing it through the analyzer.

[0012] S4, Sample Injection: Connect the sample gas to the inlet of the first switching valve, open the first and second switching valves to inject the sample for analysis.

[0013] Preferably, the method for online detection of trace neon in high-purity helium and ultrapure helium further includes the step: S1, sample pretreatment: using a pressure reducing valve to stabilize the sample gas pressure.

[0014] The helium-neon analyzer and its analytical method of this invention use a plasma emission detector to analyze helium-neon. This analyzer is not a chromatograph and does not require a carrier gas. It uses a gas purification device to purify the sample gas, removing all impurities except for helium-neon. It eliminates the need for chromatographic columns to separate gaseous impurities, directly reflecting the true concentration of neon in the sample gas, with a detection limit below 10 ppb and high sensitivity. As an online detection instrument, the helium-neon analyzer of this invention can be directly integrated into industrial production or process flows for online gas detection. It can acquire and process data in real time, continuously monitor and analyze, without requiring manual sampling or interrupting the production process, effectively improving efficiency, ensuring safety, and reducing operating costs. Attached Figure Description

[0015] Figure 1 A schematic diagram of a helium-neon analyzer according to an embodiment of the present invention is shown.

[0016] Figure 2 The linear analysis results of the helium-neon analyzer are shown. Detailed Implementation

[0017] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The exemplary embodiments described below and illustrated in the drawings are intended to teach the principles of the invention, enabling those skilled in the art to implement and use the invention in various environments and for various applications. Therefore, the scope of protection of the present invention is defined by the appended claims, and the exemplary embodiments are not intended, and should not be considered, a limiting description of the scope of protection of the present invention. Furthermore, for ease of description, the dimensions of the various parts shown in the drawings are not necessarily drawn to actual scale. Orientation or positional relationships, as indicated by orientation descriptions, are based on the orientation or positional relationships shown in the drawings and are only for the purpose of facilitating and simplifying the description of the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Unless otherwise specifically stated, the order and numerical values ​​of components and assembly steps set forth in the embodiments do not limit the scope of the present invention. Moreover, any numerical range stated herein is intended to include all sub-ranges contained therein, and a numerical range expressed as "value A to value B" refers to a range including endpoint values ​​A and B. Those skilled in the art will understand that the terms "nth," "Sn," and "step" in this invention are used only to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them. For example, two steps can be interchanged or performed in parallel.

[0018] <Overall Composition>

[0019] like Figure 1 The analyzer shown in the embodiment of the present invention for online detection of trace amounts of neon in high-purity helium and ultrapure helium (also known as a helium-neon analyzer) includes: a first switching valve 1, a purification device 2 for removing impurities other than inert gases, a plasma emission detector 3, a signal acquisition system 4, a display device 5, and a second switching valve 6.

[0020] The first switching valve 1 is used to control the gas supplied to the purification device 2.

[0021] Purification unit 2 is a zirconium vanadium iron bipolar purifier used to remove impurities such as oxygen, nitrogen, hydrogen, carbon, and methane from inert gases like helium, achieving deep purification of high-purity helium. The zirconium vanadium iron material, after activation at a specific temperature (typically 300℃~500℃), exhibits excellent getter performance, efficiently adsorbing residual gaseous impurities and thus improving gas purity. The zirconium weight percentage in the zirconium vanadium iron material is typically between 65% and 75%, a ratio that helps optimize the reaction rate while ensuring getter capacity, thereby improving overall purification efficiency. Furthermore, this material can be used in combination with other getters (such as zirconium aluminum) to enhance the comprehensive removal capacity for multiple impurities. This ensures that impurities other than neon are completely purified.

[0022] The gas purified by the purification device 2, after removing impurities other than inert gases, enters the plasma emission detector 3 for detection. The plasma emission detector 3 uses a filter that allows light with characteristic peaks of the neon plasma emission spectrum, such as 585 nm, 632 nm, and 640 nm, to pass through. It is highly sensitive to neon gas, with a detection limit as low as 10 ppb. The plasma emission detector 3 uses helium gas generated from the evaporation of liquid helium as the zero-point gas for zero-point calibration, ensuring the zero point is as accurate as possible. When testing the sample helium, the detection signal from the plasma emission detector 3 can be converted into the actual neon concentration in helium.

[0023] The second switching valve 6 is connected to the plasma emission detector 3 and is used to control the gas discharged from the plasma emission detector 3.

[0024] The signal acquisition system 4 and the display device 5 are used to acquire signals from the plasma emission detector 3, and after signal amplification, processing and analysis, the results are displayed on the display device 5.

[0025] <Analysis Steps>

[0026] Using the analyzer according to the present invention, an analytical method for online detection of trace amounts of neon in high-purity helium and ultra-pure helium is provided, comprising the following steps:

[0027] S1, Sample pretreatment: Use a pressure reducing valve to stabilize the sample gas pressure.

[0028] S2, System Preparation: The purification unit 2 of the analyzer needs to be stabilized to its operating temperature under protective gas purging. When the purification unit 2 uses a zirconium vanadium iron bipolar purifier, the operating temperature can be set to 350 degrees Celsius for the first electrode and 200 degrees Celsius for the second electrode. The protective gas is 5N high-purity helium. Connect this high-purity helium to the inlet of the first switch valve 1, open the first switch valve 1 and the second switch valve 6, turn on the analyzer, and purge for 30 minutes. Then, power on the purification unit 2 and purge for 1 hour until the temperature of the purification unit 2 stabilizes.

[0029] S3, System Calibration: Includes zero-point calibration and range point calibration, wherein...

[0030] Zero point calibration: The analyzer requires 6N helium gas (i.e., ultrapure helium) packaged by liquid helium evaporation as the zero point gas. The gas is introduced into the analyzer for analysis. The analyzer can be calibrated to zero point after the analysis results of the zero point gas have been stable for 30 minutes.

[0031] Range calibration: Use a helium standard gas containing 10 ppm neon (also known as "helium standard gas", which is a mixed gas standard gas with helium as the background or base gas) to pass into the analyzer for analysis. The analyzer's range can be calibrated after the analysis results of the helium standard gas have stabilized for 30 minutes.

[0032] Before leaving the factory, the instrument undergoes multi-point linearity verification, including zero-point verification, and the coefficient of determination R of the fitting equation is... 2 =0.999, then single-point calibration can be used.

[0033] S4, Sample Injection: Connect the sample gas to the inlet of the first switch valve 1, open the first switch valve 1 and the second switch valve 6, wait for the reading of the display device 5 to stabilize, and then record the analysis results.

[0034] Here, the neon content in high-purity helium is expressed in ppmv, and the neon content in ultra-pure helium is expressed in ppbv.

[0035] Performance Analysis

[0036] 1. Instrument linearity: Experimental data shown in Table 1 below demonstrate that the helium-neon analyzer according to embodiments of the present invention can accurately detect trace amounts of neon in helium from 0-10 ppm. Within the measurement range, it exhibits good linearity, including low concentrations (0-0.2 ppm), with a coefficient of determination R0. 2 The concentration can reach 0.999. The test method is as follows: using a helium standard gas containing 10.14 ppm neon, 6N helium gas (referred to as zero point gas in Table 1 and hereinafter) packaged by liquid helium evaporation is mixed and diluted in a diluent to 50%, 25%, 10%, 5%, 2%, and 1% of the original helium standard gas concentration. The analytical results of the mixed gas, undiluted standard gas, and zero point gas at different concentrations are measured, i.e., the detector response of the plasma emission detector 5. The actual neon concentration in helium and the detector response are linearly fitted. The theoretical total flow rate of the zero point gas and helium standard gas input to the diluent is 200 sccm, and the theoretical flow rate of the mixed gas output from the diluent is 70 sccm. The flow rates filled in Table 1 are the actual flow rates during diluent mixing, and the neon concentration in the mixed gas is calculated based on the actual flow rate of the diluent.

[0037] Table 1:

[0038]

[0039] 2. Instrument Detection Limit: The experimental data shown in Table 2 indicate that the detection limit of the helium-neon analyzer according to this embodiment of the invention can reach 10 ppb for the detection of helium-neon. The calculation was based on the IUPAC definition, using a method based on the standard deviation of the blank response. Ten sets of blank samples (zero-point gas) were continuously tested, and the standard deviation (SB) of the detector response of the plasma emission detector 5 for these ten sets of blank samples was calculated. The instrument's detection limit was then obtained according to the equation DL (detection limit) = 3.3 * SB / K, where K is the slope of the instrument's linear equation, and its value is taken from... Figure 2 The slope of the linear equation in the equation is 121.4.

[0040] Table 2:

[0041]

[0042] <Technical Effects>

[0043] The online analyzer for detecting trace amounts of neon in high-purity helium and ultrapure helium provided by the present invention has the following advantages compared with traditional gas chromatography:

[0044] Helium saving: No carrier gas consumption, low sample gas consumption, far less than the helium consumption of the chromatograph;

[0045] Unlike traditional chromatographs where the results are affected by the neon content in the carrier gas, this invention can directly reflect the true concentration of neon in the sample gas, and the detection limit can reach below 10 ppb, with sensitivity higher than all currently known detection methods.

[0046] Using a gas purification device to purify the sample gas can remove all impurities except helium and neon, preventing impurities from interfering with the detection of helium and neon, and eliminating the need to use a chromatographic column to separate gaseous impurities.

[0047] Using filters specific to the emission spectrum of neon gas to filter out background light interference and enhance the sensitivity of neon detection in helium;

[0048] The response time of the plasma emission detector 5 is less than 30 seconds;

[0049] It can reflect the current helium-neon concentration in real time.

[0050] In the description of this application, "a plurality of" means two or more, unless otherwise expressly specified. Unless otherwise expressly specified and limited, the terms "installed," "connected," "linked," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Although the invention has been described with reference to various specific embodiments, it should be understood that modifications can be made within the spirit and scope of the described inventive concept. Therefore, it is intended that the invention be limited to the described embodiments but will have the full scope defined by the language of the appended claims.

Claims

1. An analyzer for online detection of trace amounts of neon in high-purity helium and ultra-pure helium, characterized in that, include: The system comprises a first switching valve (1), a purification device (2), a plasma emission detector (3), a signal acquisition system (4), a display device (5), and a second switching valve (6). The first switching valve (1) controls the gas supplied to the purification device (2), which is used to remove impurities other than inert gases. The plasma emission detector (3) uses a filter that allows light with the characteristic peaks of the neon plasma emission spectrum at 585 nm, 632 nm, and 640 nm to pass through. The second switching valve (6) is connected to the plasma emission detector (3) and controls the gas discharged from the plasma emission detector (3). The signal acquisition system (4) is used to acquire signals from the plasma emission detector (3), and the display device (5) is used to display the analysis results of the signals.

2. The analyzer for online detection of trace amounts of neon in high-purity helium and ultra-pure helium according to claim 1, characterized in that, The purification device (2) is a zirconium vanadium iron bipolar purifier, used to remove impurities from helium.

3. The analyzer for online detection of trace neon in high-purity helium and ultra-pure helium according to claim 1, characterized in that, The plasma emission detector (3) can use helium gas generated by the evaporation of liquid helium as the zero-point gas for zero-point calibration.

4. A method for online detection of trace amounts of neon in high-purity helium and ultra-pure helium, characterized in that, The online analyzer for detecting trace amounts of neon in high-purity helium and ultra-pure helium according to any one of claims 1 to 3 includes the following steps: S2, System preparation: Stabilize the purification device (2) to the working temperature under protective gas purging, wherein the first electrode of the purification device (2) is 350 degrees Celsius, the second electrode is 200 degrees Celsius, and the protective gas is 5N high-purity helium. Connect the high-purity helium to the inlet of the first switch valve (1), open the first switch valve (1) and the second switch valve (6), turn on the analyzer to purge for the first predetermined time, and then turn on the purification device (2) to continue purging for the second predetermined time. S3, System Calibration: Includes zero-point calibration and range point calibration, wherein... Zero-point calibration: The analyzer uses 6N helium gas, packaged via liquid helium evaporation, as the zero-point gas. This gas is introduced into the analyzer for analysis to calibrate the analyzer's zero point. Range calibration: Use a helium standard gas containing 10 ppm neon to calibrate the analyzer's range by passing it through the analyzer. S4, Sample Injection: Connect the sample gas to the inlet of the first switch valve (1), open the first switch valve (1) and the second switch valve (6) to inject the sample for analysis.

5. The method for online detection of trace neon in high-purity helium and ultrapure helium according to claim 4, characterized in that, It also includes the following steps: S1, sample pretreatment: using a pressure reducing valve to stabilize the sample gas pressure.

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