Automatic sampling analysis system and method for measuring trace halide in hydrogen

Abstract

The invention discloses an automatic sampling analysis system and an automatic sampling analysis method for determining trace halide in hydrogen, which are characterized in that gas absorption units connected in series in multiple stages are combined with alkaline absorption liquid, so that the halide in the hydrogen is fully captured in a gas-liquid contact path, the absorption effect on chloride, fluoride and other components is obviously improved, and the quality of the hydrogen is improved. And the accuracy of the total halide detection result is ensured. In the whole process, absorption liquid adding, absorption liquid merging and volume fixing after sampling and sample conveying are automatically completed through the controller, uncertainty caused by manual operation is eliminated, and the stability of a detection result and the working efficiency are improved. Furthermore, the online monitoring unit can reflect the state of the absorption process in real time, so that the sampling end point judgment is more reliable. The whole system can be conveniently combined with analysis equipment such as an ion chromatograph, and is suitable for high-standard detection requirements of trace halides in high-purity hydrogen.

Description

Technical Field

[0001] This invention relates to the field of gas analysis and detection technology, and in particular to an automated sampling and analysis system and method for determining trace halides in hydrogen gas. Background Technology

[0002] With the rapid development of fuel cell vehicles, the requirements for controlling the impurity content in fuel hydrogen are becoming increasingly stringent. International standard ISO 14687:2019 and national standard GB / T 37244-2018 both specify stringent limits for the total halide content in hydrogen (e.g., ≤0.05 μmol / mol). Therefore, developing highly sensitive and accurate halide detection methods is crucial.

[0003] Currently, the widely adopted standard method (such as Appendix A of GB / T 37244-2018) is based on solution absorption-ion chromatography. Its basic procedure is as follows: a certain volume of hydrogen gas to be tested is passed into a wash bottle containing deionized water at a constant flow rate, allowing the halides to be absorbed by the absorption solution. After sampling, the absorption solution is diluted to a final volume and analyzed using an ion chromatograph.

[0004] However, this method has the following significant drawbacks in practical applications: The absorption efficiency is limited, especially for poorly soluble components: using deionized water as the absorbent has a decent absorption effect on easily soluble gases such as hydrogen chloride (HCl), but the absorption efficiency for halides with low solubility such as chlorine (Cl2) is very poor (reported in the literature as about 23.4%), which leads to a serious underestimation of the "total halides" measurement results and fails to truly reflect the quality of hydrogen.

[0005] The process is cumbersome and prone to human error: the entire sampling, volume adjustment, and transfer process relies entirely on manual operation, including the addition of absorbent, control of sampling time, and manual volume adjustment and transfer after sampling. The steps are complicated and prone to random errors due to operator differences, affecting the repeatability and accuracy of the test.

[0006] Unable to monitor the sampling process in real time: Traditional devices lack process monitoring methods. Issues such as whether the sampling is complete, whether the absorbent is saturated, and whether there is leakage cannot be known during the process. These issues can only be determined after the analysis is completed, which may lead to invalid sampling and waste of resources.

[0007] Insufficient sensitivity for trace analysis: For the detection of trace halides below 0.05 μmol / mol, traditional single-stage absorption devices may cause trace components to escape due to insufficient gas-liquid contact, making it difficult to further reduce the method detection limit.

[0008] Therefore, there is an urgent need for an improved technology and device that can achieve efficient, automated, and high-precision sampling and is suitable for the determination of trace halides. Summary of the Invention

[0009] To address the technical problems existing in the background art, the present invention proposes an automated sampling and analysis system and method for the determination of trace halides in hydrogen.

[0010] This invention proposes an automated sampling and analysis system for the determination of trace halides in hydrogen gas, comprising: Gas source interface, used to connect to a hydrogen source; A gas flow control and metering unit, whose inlet is connected to the gas source interface, is used to control the hydrogen flow rate and meter the hydrogen volume. The sampling absorption module includes multiple gas absorption units connected in series, each of which contains an alkaline absorption liquid. The inlet of the sampling absorption module is connected to the outlet of the gas flow control and metering unit. An automatic control and injection module includes a controller, a liquid delivery unit, a valve unit, and a volumetric adjustment unit; the controller is electrically connected to the liquid delivery unit and the valve unit; the liquid delivery unit is fluidly connected to each gas absorption unit and the volumetric adjustment unit through the valve unit; the controller is configured to control the liquid delivery unit and the valve unit to automatically inject the alkaline absorbent into each gas absorption unit, and automatically combine and transfer the absorbents from each gas absorption unit to the volumetric adjustment unit for volumetric adjustment after sampling.

[0011] Preferably, the sampling absorption module includes at least three gas absorption units connected in series. The gas absorption units are gas washing bottles made of perfluoroalkoxyalkane material, and the inlet and outlet of each gas washing bottle are connected in series via pipelines.

[0012] Preferably, the alkaline absorption solution is a sodium hydroxide (NaOH) or potassium hydroxide (KOH) solution with a concentration of 0.001 mol / L to 1 mol / L.

[0013] Preferably, it further includes an online monitoring unit for monitoring the absorption of halides. The online monitoring unit is located at the gas outlet or liquid outlet of the last stage gas absorption unit and is electrically connected to the controller.

[0014] Preferably, the online monitoring unit is a multi-channel monitoring module, which is connected to the gas outlet or liquid outlet of each stage of the gas absorption unit, and the monitoring points are periodically switched by the controller.

[0015] Preferably, the volumetric flask or metering ring is used as the volumetric flask, the liquid delivery unit is a peristaltic pump, and the controller is configured to control the volumetric flask, the peristaltic pump and the valve unit to cooperate in automatically merging the absorbents at each stage and bringing the volume to a preset volume.

[0016] This invention presents an automated sampling and analysis system for the determination of trace halides in hydrogen. By combining multi-stage cascaded gas absorption units with an alkaline absorbent, the system ensures the complete capture of halides in the hydrogen gas during the gas-liquid contact path, significantly improving the absorption of components such as chlorides and fluorides and guaranteeing the accuracy of total halide detection results. The entire process is automated by the controller, including absorbent addition, post-sampling absorbent merging and volume adjustment, and sample delivery. This eliminates uncertainties caused by manual operation and improves the stability and efficiency of the detection results. Furthermore, the online monitoring unit can reflect the absorption process status in real time, making the determination of the sampling endpoint more reliable. The entire system can be easily integrated with analytical equipment such as ion chromatographs and is suitable for high-standard detection requirements of trace halides in high-purity hydrogen.

[0017] This invention also proposes an automated sampling and analysis method based on the above-described automated sampling and analysis system for the determination of trace halides in hydrogen, comprising the following steps: S1. The hydrogen gas to be tested is sequentially passed into the alkaline absorption liquid of multiple gas absorption units, so that the halides are absorbed by the alkaline absorption liquid, and an absorption liquid containing the captured products is obtained. S2. Combine the absorbent liquids containing the captured products from multiple gas absorption units and bring the volume to a preset level to obtain the sample after volume adjustment. S3. The sample after volume adjustment is transported to an analytical instrument for detection to obtain the halide content.

[0018] Preferably, in S2, the absorption of halides is monitored to determine whether the absorption is complete.

[0019] Preferably, the exhaust gas is monitored for unabsorbed acidic gases based on the conductivity value at the outlet of the last-stage gas absorption unit, thereby determining whether absorption is complete.

[0020] Preferably, in S2, after sampling and absorption are completed, the absorbent liquid in the multiple gas absorption units is transferred to the volume-fixing unit, and then the pipeline is flushed with pure water and the flushing liquid is sent to the volume-fixing unit for mixing and final volume fixation.

[0021] The automated sampling and analysis method for determining trace halides in hydrogen proposed in this invention has similar technical effects to the above-mentioned analysis system, and therefore will not be described in detail. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of one embodiment of an automated sampling and analysis system for determining trace halides in hydrogen, as proposed in this invention.

[0023] Figure label: 1. Hydrogen source; 2. Pressure reducing valve; 3. Mass flow controller; 4. Gas absorption unit; 4a. First-stage PFA gas scrubbing bottle; 4b. Second-stage PFA gas scrubbing bottle; 4c. Third-stage PFA gas scrubbing bottle; 4d, fourth-stage PFA gas scrubbing bottle; 5. Gas flow meter; 6. Online conductivity meter; 7. Controller; 8. Peristaltic pump; 9. Solenoid valve; 10. Multi-port switching valve; 11. Constant-volume unit; 12. Ion chromatograph. Detailed Implementation

[0024] Reference Figure 1 The present invention proposes an automated sampling and analysis system for the determination of trace halides in hydrogen, comprising: a gas source interface, a gas flow control and metering unit, a sampling and absorption module, and an automatic control and injection module.

[0025] The gas source interface is used to connect to hydrogen source 1; wherein, the gas source interface is a physical connector for connecting to an external gas source, such as a quick-connect connector or a threaded connector.

[0026] The gas flow control and metering unit has its inlet connected to the gas source interface and is used to control the hydrogen flow rate and meter the hydrogen volume. The gas flow control and metering unit may include a mass flow controller 3 (MFC).

[0027] The sampling absorption module includes multiple gas absorption units 4 connected in series. Each gas absorption unit 4 contains an alkaline absorbent, and the inlet of the sampling absorption module is connected to the outlet of the gas flow control and metering unit. Specifically, the sampling absorption module includes at least three gas absorption units 4 connected in series. Each gas absorption unit 4 uses a gas washing bottle made of perfluoroalkoxyalkane material, and the inlet and outlet of each gas washing bottle are connected in series via pipelines. This series design significantly extends the gas-liquid contact path and time, ensuring that trace components are fully absorbed. The alkaline absorbent is a sodium hydroxide (NaOH) or potassium hydroxide (KOH) solution with a concentration of 0.001 mol / L to 1 mol / L. More preferably, it is a NaOH solution of about 5 mmol / L. The alkaline environment can chemically react with halides (such as Cl2), converting them into ionic forms that are more soluble in water (such as Cl2). - , ClO -This increases the chlorine absorption efficiency from approximately 23.4% to over 60%.

[0028] An automatic control and injection module includes a controller 7, a liquid delivery unit, a valve unit, and a volumetric adjustment unit 11. The controller 7 is electrically connected to the liquid delivery unit and the valve unit. The liquid delivery unit is fluidly connected to each of the gas absorption units 4 and the volumetric adjustment unit 11 via the valve units. The controller 7 is configured to control the liquid delivery unit and the valve unit to automatically inject the alkaline absorbent into each of the gas absorption units 4, and to automatically combine and transfer the absorbents from each of the gas absorption units 4 to the volumetric adjustment unit 11 for volumetric adjustment after sampling.

[0029] The liquid delivery unit may employ a multi-channel peristaltic pump 8, used to perform functions such as adding absorbent, combining absorbents, and delivering samples to the analytical instrument. The volumetric flask or metering loop is used to make the volumetric flask 11, and the controller 7 is configured to control the volumetric flask 11, the peristaltic pump 8, and the valve unit to automatically combine the absorbents at each stage and make the volume to a preset volume.

[0030] In the specific sampling and analysis process of the automated sampling and analysis system for determining trace halides in hydrogen according to this embodiment, the hydrogen gas to be tested is first introduced through the gas source interface, and the gas flow rate is controlled by the gas flow control and metering unit. Alkaline absorbent liquid is then sequentially introduced into multiple gas absorption units 4 of the sampling absorption module, allowing the halides to be absorbed by the alkaline absorbent liquid, resulting in an absorbent liquid containing the captured products. Then, the absorbent liquids containing the captured products from the multiple gas absorption units 4 are combined and brought to a preset volume to obtain a final volume sample. Finally, the final volume sample is transported to an analytical instrument for detection to obtain the halide content.

[0031] In this embodiment, the proposed automated sampling and analysis system and method for determining trace halides in hydrogen gas utilizes a multi-stage series gas absorption unit 4 combined with an alkaline absorbent. This ensures that halides in hydrogen gas are fully captured in the gas-liquid contact path, significantly improving the absorption effect on components such as chlorides and fluorides, and guaranteeing the accuracy of total halide detection results. The entire process is automated by the controller 7, which completes the addition of absorbent, merging and volume adjustment of absorbent after sampling, and sample delivery, eliminating the uncertainties caused by manual operation and improving the stability and efficiency of detection results.

[0032] In a specific embodiment, the automated sampling and analysis system for determining trace halides in hydrogen gas further includes an online monitoring unit for monitoring halide absorption. This online monitoring unit is located at the outlet or liquid outlet of the last-stage gas absorption unit 4 and is electrically connected to the controller 7. The online monitoring unit may include a conductivity meter 6 and a gas flow meter 5. By monitoring changes in the conductivity of the effluent or tail gas, it can determine whether absorption is complete, thus achieving intelligent determination of the sampling endpoint. During gas absorption, based on the conductivity value at the outlet of the last-stage gas absorption unit 4, it monitors whether the tail gas still contains unabsorbed acidic gases, thereby determining whether absorption is complete. After sampling and absorption are completed, the absorbent liquid from multiple gas absorption units is transferred to a volume-fixing unit. Then, the pipeline is flushed with pure water, and the flushing liquid is sent to the volume-fixing unit for mixing and final volume adjustment.

[0033] In practical design, the online monitoring unit is a multi-channel monitoring module. This module is connected to the gas outlet or liquid outlet of each stage of the gas absorption unit 4, and the monitoring points are periodically switched via the controller 7. The online monitoring unit can reflect the absorption process status in real time, making the determination of the sampling endpoint more reliable. The entire system can be easily integrated with analytical equipment such as ion chromatographs, and is suitable for high-standard detection requirements of trace halides in high-purity hydrogen.

[0034] Based on the real-time monitoring data acquired by the online monitoring unit, it is determined whether there is a risk of halide migrating from the previous gas absorption unit to the next gas absorption unit in a breakthrough manner. Specifically, the risk of breakthrough migration refers to the phenomenon that the target halide fails to be effectively captured and enters the subsequent unit in large quantities due to the saturation of the absorbent in the previous absorption unit, a sudden decrease in absorption efficiency, or the inlet gas concentration far exceeding the design value.

[0035] In specific risk assessment, the controller reads data from the online monitoring unit at a fixed frequency during sampling. For conductivity monitoring, the controller not only focuses on the instantaneous value but, more importantly, calculates its rate of change over time (dC / dt). A "risk threshold curve" can be pre-stored within the system, defining a safe upper limit for the rate of change of conductivity at different sampling stages (initial, middle, and late stages). After the middle stage of sampling, if the rate of change of conductivity exceeds the safe upper limit for three consecutive monitoring cycles, the logic judgment module determines that there is a "breakthrough migration risk." Furthermore, during sampling, the outlet monitoring value of the last-stage gas absorption unit can be periodically compared with a preset threshold. If the outlet monitoring value shows a continuous upward trend or approaches the threshold prematurely at the end of the sampling period, it is determined that the preceding absorption unit may be saturated or experiencing a decrease in absorption efficiency, indicating a "breakthrough migration risk."

[0036] When the aforementioned risk is determined to exist, a preset anti-escape protection procedure is automatically executed. This anti-escape protection procedure is a set of operational instructions automatically triggered by the controller to prevent the loss of the target component or ensure its eventual capture.

[0037] In one specific implementation of the escape prevention safeguard procedure, the escape prevention safeguard procedure includes adjusting the hydrogen flow rate of the gas flow control and metering unit. When a "breakthrough migration risk" is determined, the controller immediately pauses the sampling timing and adjusts the gas flow control and metering unit to reduce the hydrogen flow rate, thereby reducing the hydrogen flow velocity and extending its residence time in the absorption unit.

[0038] In another specific implementation of the escape prevention procedure, the sampling absorption module further includes at least one backup absorption unit containing alkaline absorbent. This backup absorption unit is connected in parallel with at least one primary gas absorption unit via a backup pipeline, or in series with a multi-stage gas absorption unit 4. When a "breakthrough migration risk" is detected, the controller activates the backup absorption unit, allowing the gas to pass through it. Furthermore, the controller can read the preset absorbent volume in the backup unit and, based on the final online detection results, quantitatively replenish the absorbent volume in the backup unit using a peristaltic pump.

[0039] By assessing breakthrough migration risks and implementing escape prevention measures, the system possesses the ability to self-sensitize and respond to anomalies in the sampling process. It can proactively prevent the escape of trace target components caused by performance degradation of the absorption unit or sudden changes in sample concentration, thereby fundamentally avoiding low or invalid detection results due to such unexpected situations. This greatly improves the robustness of the automated sampling process and the reliability of the measurement results, which is especially crucial for ensuring the accuracy of ppb-level trace halide detection.

[0040] The analysis process of the automated sampling and analysis system in this embodiment includes the following steps: S1. System preparation: The liquid delivery unit and valve unit are started by the controller 7 to automatically and quantitatively inject the alkaline absorbent into the multi-stage gas absorption unit 4 connected in series.

[0041] S2. Sampling and absorption: The hydrogen gas to be tested is sequentially passed into the multi-stage gas absorption unit 4 containing alkaline absorption liquid at a set constant flow rate, and the halides are absorbed efficiently stage by stage; the online monitoring unit monitors the absorption effect in real time.

[0042] Specifically, the online monitoring unit is a conductivity meter 6. When the conductivity value of the effluent or exhaust gas tends to stabilize or reaches a set threshold, it is determined that the absorption is complete, and the controller 7 can automatically end the sampling or prompt the operator.

[0043] S3. Automatic volume adjustment: After sampling, the controller 7 controls the valve unit to switch the flow path and starts the liquid delivery unit to automatically combine the absorbent in the multi-stage gas absorption unit 4 and transfer it to the volume adjustment unit 11 for precise dilution and volume adjustment to the preset volume.

[0044] S4. Automatic Sample Injection and Analysis: The controller 7 controls the liquid delivery unit to automatically deliver the diluted sample solution to the autosampler of the ion chromatograph 12, whereby the ion chromatograph 12 completes the separation and quantitative detection of halide ions.

[0045] Compared with the prior art, this embodiment has the following significant advantages: 1. Significantly improved absorption efficiency: The combination of "multi-stage series absorption bottles + alkaline absorption liquid" integrates two enhancement mechanisms: physical (increasing contact path) and chemical (neutralization reaction). In particular, the absorption efficiency of chlorine can be increased from about 23.4% of the traditional method to more than 60%, ensuring the accuracy of total halide detection results.

[0046] 2. High degree of automation and high precision: The entire process from liquid addition, sampling, volume adjustment to sample injection is automated through PLC and other controllers, which completely eliminates random errors caused by manual operation, greatly improves the repeatability and precision of test results, and reduces the labor intensity of operators.

[0047] 3. Controllable and intelligent: The added online monitoring unit (such as a conductivity meter) can reflect the absorption process in real time, realize intelligent judgment of the sampling endpoint, avoid oversampling or undersampling, ensure the effectiveness of each sampling, and save gas and reagents.

[0048] 4. Suitable for trace analysis: The efficient absorption design and automated precise control effectively reduce the background and losses in the entire analysis process, and significantly reduce the limit of detection (LOD) and limit of quantitation (LOQ) for trace halides, fully meeting the detection requirements for ppb-level impurities in high-purity hydrogen.

[0049] 5. Strong compatibility and scalability: The core of this system is the sampling pretreatment device, which can be used in conjunction with various detection terminals (such as ion chromatographs, ion trap mass spectrometers, etc.). Its automated control logic can also be extended to other similar gas absorption sampling scenarios.

[0050] The following detailed description of the automated sampling and analysis system and method for determining trace halides in hydrogen gas is provided through specific embodiments, but is not intended to limit the invention.

[0051] like Figure 1As shown, this embodiment provides a complete automated sampling and analysis system. The hydrogen gas output from the hydrogen source 1 (such as a high-pressure hydrogen cylinder) is depressurized by the pressure reducing valve 2, and then the flow rate is controlled by the mass flow controller (MFC) 3 to enter the sampling and absorption module at a stable flow rate (e.g., 500 mL / min).

[0052] The sampling absorption module consists of four series-connected PFA gas washing bottles (4a, 4b, 4c, 4d). Each washing bottle contains approximately 50 mL of 5 mmol / L NaOH solution, pre-filled with the absorbent by a multi-channel peristaltic pump 8 controlled by a solenoid valve 9. The hydrogen gas to be tested passes sequentially through these four washing bottles, where halides (such as HCl, Cl2, HF, etc.) are absorbed efficiently and progressively by the alkaline absorbent. Cl2, in particular, reacts with NaOH to form NaCl and NaClO, thus being effectively captured.

[0053] An online conductivity meter 6 can be optionally installed in the outlet line of the final washing bottle (4d) to monitor whether the exhaust gas still contains unabsorbed acidic gases (the conductivity change slows down when absorption is complete). The gas flow then passes through a wet gas flow meter 5 to measure the total volume.

[0054] After sampling and absorption are completed, the controller (PLC) 7 begins the automatic volume-dilution program. PLC 7 controls the multi-channel peristaltic pump 8 and the multi-port switching valve 10 to sequentially aspirate and combine the absorbent from the four-stage wash bottles (4a-4d) and transfer it to a 200 mL precision volume-dilution unit 11. Subsequently, the peristaltic pump 8 automatically adds ultrapure water to flush the pipeline and incorporates the flushing solution into the volume-dilution unit, finally bringing the volume to the 200.0 mL mark and mixing thoroughly.

[0055] After volume adjustment, PLC 7 controls switching valve 10 and peristaltic pump 8 to directly and without transfer the adjusted sample solution to the autosampler vial of ion chromatograph 12 (or directly via quantitative loop). The ion chromatograph then analyzes the halogen anions (F2) in the sample according to a preset analytical method (e.g., using an IonPac AS19 column with KOH gradient elution). - , Cl - ,Br - Separation and detection are carried out using (etc.).

[0056] Throughout the entire process, from adding liquid, initiating sampling, determining the sampling endpoint (based on time or flow meter signal), performing volume adjustment, to sample preparation, everything is automatically controlled by PLC 7 according to a preset program, requiring no manual intervention. Data from the online conductivity meter 6 can also be fed back to PLC 7 to optimize the sampling strategy.

[0057] Comparison and effect data To verify the effectiveness of the present invention, the same standard hydrogen gas sample containing 0.02 μmol / mol HCl and 0.02 μmol / mol Cl2 was sampled and analyzed using the conventional single-stage deionized water absorption method (control example) and the four-stage alkaline absorption automatic system of the present invention (example). The sampling volume was 100 L and the final volume was 100 mL.

[0058] Absorption efficiency: The control example has an absorption efficiency of about 25% for Cl2 and close to 100% for HCl; the example improves the absorption efficiency of Cl2 to over 65% and maintains close to 100% for HCl.

[0059] Repeatability testing: The same standard sample was measured six times consecutively, and the total chlorine (as Cl) in the control example was measured. - The RSD (relative standard deviation) of the calculated result was 8.7%; the RSD of the example result was 1.5%.

[0060] Spike recovery rate: Spike recovery experiments were conducted on the samples. The recovery rates of the examples for low, medium and high concentrations of spikes were between 95% and 105%, while the recovery rate of the control examples for low concentration spikes was only 70% to 80%.

[0061] Operation time: To complete a full process from preparation to injection, the control example requires approximately 60 minutes of manual operation; the example only requires initial setup and runs fully automatically in about 40 minutes, with less than 5 minutes of manual operation.

[0062] The above data show that the system and method of the present invention are significantly superior to traditional methods in terms of absorption efficiency, analytical precision, accuracy and automation, and are particularly suitable for high-standard detection of trace impurities in high-purity gases such as hydrogen used in fuel cells.

[0063] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An automated sampling and analysis system for the determination of trace halides in hydrogen gas, characterized in that, include: Gas source interface, used to connect to a hydrogen source; A gas flow control and metering unit, whose inlet is connected to the gas source interface, is used to control the hydrogen flow rate and meter the hydrogen volume. The sampling absorption module includes multiple gas absorption units connected in series, each of which contains an alkaline absorption liquid. The inlet of the sampling absorption module is connected to the outlet of the gas flow control and metering unit. An automatic control and injection module includes a controller, a liquid delivery unit, a valve unit, and a volumetric adjustment unit; the controller is electrically connected to the liquid delivery unit and the valve unit; the liquid delivery unit is fluidly connected to each gas absorption unit and the volumetric adjustment unit through the valve unit; the controller is configured to control the liquid delivery unit and the valve unit to automatically inject the alkaline absorbent into each gas absorption unit, and automatically combine and transfer the absorbents from each gas absorption unit to the volumetric adjustment unit for volumetric adjustment after sampling.

2. The automated sampling and analysis system for determining trace halides in hydrogen according to claim 1, characterized in that, The sampling absorption module includes at least three gas absorption units connected in series. The gas absorption units are gas washing bottles made of perfluoroalkoxyalkane material, and the inlet and outlet of each gas washing bottle are connected in series through pipelines.

3. The automated sampling and analysis system for determining trace halides in hydrogen according to claim 1, characterized in that, The alkaline absorbent is a sodium hydroxide or potassium hydroxide solution with a concentration of 0.001 mol / L to 1 mol / L.

4. The automated sampling and analysis system for determining trace halides in hydrogen according to claim 1, characterized in that, It also includes an online monitoring unit for monitoring the absorption of halides. The online monitoring unit is located at the gas outlet or liquid outlet of the last stage gas absorption unit and is electrically connected to the controller.

5. The automated sampling and analysis system for determining trace halides in hydrogen according to claim 4, characterized in that, The online monitoring unit is a multi-channel monitoring module, which is connected to the gas outlet or liquid outlet of each stage of the gas absorption unit, and the monitoring points are periodically switched by the controller.

6. The automated sampling and analysis system for determining trace halides in hydrogen according to claim 1, characterized in that, The volumetric flask or metering ring is used as the volumetric flask, the liquid delivery unit is a peristaltic pump, and the controller is configured to control the volumetric flask, the peristaltic pump and the valve unit to cooperate in automatically merging the absorbents at each stage and bringing the volume to a preset volume.

7. An automated sampling and analysis method based on the automated sampling and analysis system for the determination of trace halides in hydrogen according to any one of claims 1-6, characterized in that, Includes the following steps: S1. The hydrogen gas to be tested is sequentially passed into the alkaline absorption liquid of multiple gas absorption units, so that the halides are absorbed by the alkaline absorption liquid, and an absorption liquid containing the captured products is obtained. S2. Combine the absorbent liquids containing the captured products from multiple gas absorption units and bring the volume to a preset level to obtain the sample after volume adjustment. S3. The sample after volume adjustment is transported to an analytical instrument for detection to obtain the halide content.

8. The automated sampling and analysis method according to claim 7, characterized in that, In S2, the absorption of halides is monitored to determine whether the absorption is complete.

9. The automated sampling and analysis method according to claim 8, characterized in that, Based on the conductivity value at the outlet of the last stage gas absorption unit, monitor whether the exhaust gas still contains unabsorbed acidic gases, thereby determining whether absorption is complete.

10. The automated sampling and analysis method according to claim 7, characterized in that, In S2, after sampling and absorption are completed, the absorbent liquid in multiple gas absorption units is transferred to the volume-fixing unit. Then, pure water is used to flush the pipeline and the flushing liquid is sent to the volume-fixing unit for mixing and final volume fixation.

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