CN-122017267-A - Automated sampling analysis system and method for measuring trace halide in hydrogen

CN122017267ACN 122017267 ACN122017267 ACN 122017267ACN-122017267-A

Abstract

The invention discloses an automatic sampling analysis system and method for measuring trace halide in hydrogen, which are used for fully trapping the halide in the hydrogen in a gas-liquid contact path by combining a gas absorption unit and an alkaline absorption liquid which are connected in series in multiple stages, so that the absorption effect on components such as chloride and fluoride is obviously improved, and the accuracy of the detection result of the total halide is ensured. The whole flow automatically completes the addition of the absorption liquid, the merging and volume fixing of the absorption liquid after sampling and the sample conveying by the controller, thereby eliminating the uncertainty caused by manual operation and improving the stability and the working efficiency of the detection result. Furthermore, the on-line monitoring unit can reflect the state of the absorption process in real time, so that the judgment of the sampling end point is more reliable. The whole system can be conveniently combined with analysis equipment such as an ion chromatograph, and is suitable for the high-standard detection requirement of trace halide in high-purity hydrogen.

Inventors

CUI CHUANSHENG
LI YANG
YAN YAN
LI QUANWEI
NING PENG

Assignees

东华工程科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260410

Claims (10)

1. An automated sampling analysis system for the determination of trace halides in hydrogen gas, comprising: the gas source interface is used for being connected with a hydrogen source; The gas inlet of the gas flow control and metering unit is connected with the gas source interface and is used for controlling the flow of hydrogen and metering the volume of hydrogen; The sampling absorption module comprises a plurality of gas absorption units which are connected in series, wherein alkaline absorption liquid is contained in each gas absorption unit, and an air inlet of the sampling absorption module is connected with an air outlet of the gas flow control and metering unit; The automatic control and sample injection module comprises a controller, a liquid conveying unit, a valve unit and a constant volume unit, wherein the controller is electrically connected with the liquid conveying unit and the valve unit, the liquid conveying unit is respectively in fluid connection with each gas absorbing unit and the constant volume unit through the valve unit, the controller is configured to control the liquid conveying unit and the valve unit to automatically inject the alkaline absorbing liquid into each gas absorbing unit, and after sampling is finished, the absorbing liquid in each gas absorbing unit is automatically combined and transferred into the constant volume unit for constant volume.
2. The automated sampling analysis system for the determination of trace halides in hydrogen according to claim 1, wherein the sampling absorption module comprises at least three stages of gas absorption units in series, the gas absorption units are gas washing bottles made of perfluoroalkoxyalkane materials, and the gas inlet and the gas outlet of each gas washing bottle are sequentially connected in series through a pipeline.
3. The automated sampling analysis system for the determination of trace halides in hydrogen according to claim 1, wherein the alkaline absorption liquid is a sodium hydroxide or potassium hydroxide solution having a concentration of 0.001 mol/L to 1 mol/L.
4. The automated sampling analysis system for trace halide determination in hydrogen of claim 1, further comprising an on-line monitoring unit for monitoring halide absorption, the on-line monitoring unit being disposed at an outlet or a liquid outlet of the gas absorption unit of the last stage and being electrically connected to the controller.
5. The automated sampling analysis system for the determination of trace halides in hydrogen according to claim 4, wherein the on-line monitoring unit is a multi-channel monitoring module connected to the gas outlet or liquid outlet of each stage of the gas absorption unit, respectively, and periodically switches monitoring points by the controller.
6. The automated sampling analysis system for trace halide determination in hydrogen of claim 1, wherein the volumetric unit is a volumetric flask or a dosing ring, the liquid delivery unit employs a peristaltic pump, and the controller is configured to control the volumetric unit, peristaltic pump, and valve unit to cooperate to achieve automatic combining of the absorption liquids at each level and volumetric to a preset volume.
7. An automated sampling analysis method based on an automated sampling analysis system for the determination of trace halides in hydrogen according to any one of claims 1 to 6, characterized by the following steps: s1, sequentially introducing hydrogen to be detected into alkaline absorption liquid of a plurality of gas absorption units to enable halides to be absorbed by the alkaline absorption liquid, so as to obtain absorption liquid containing capturing products; s2, merging absorption liquids containing captured products in the plurality of gas absorption units to a preset volume to obtain a fixed-volume sample; And S3, conveying the constant-volume sample to an analysis instrument for detection to obtain the halide content.
8. The automated sampling analysis method of claim 7, wherein in S2, halide absorption is monitored to determine if absorption is complete.
9. The automated sampling analysis method of claim 8, wherein the tail gas is monitored for unabsorbed acid gas based on the conductivity value of the outlet of the last stage gas absorption unit to determine if absorption is complete.
10. The automated sampling analysis method according to claim 7, wherein in S2, after the sampling absorption is completed, the absorption liquid in the plurality of gas absorption units is transferred to the constant volume unit, and then the pipeline is rinsed with pure water and the rinsing liquid is sent to the constant volume unit, and mixed and finally the constant volume is achieved.

Description

Automated sampling analysis system and method for measuring trace halide in hydrogen Technical Field The invention relates to the technical field of gas analysis and detection, in particular to an automatic sampling analysis system and method for measuring trace halide in hydrogen. Background With the rapid development of fuel cell automobiles, the control requirements on the impurity content in fuel hydrogen gas are increasingly strict. International standard ISO 14687:2019 and national standard GB/T37244-2018 both set stringent limits (e.g. 0.05 μmol/mol) on the total halide content in hydrogen. Therefore, it is important to develop a halide detection method with high sensitivity and high accuracy. Currently, the standard methods widely used (as in GB/T37244-2018 appendix A) are based on solution absorption-ion chromatography. The basic flow is that a certain volume of hydrogen to be measured is introduced into a washing bottle containing deionized water at a constant flow rate, so that halide is absorbed by absorption liquid, and the absorption liquid after sampling is analyzed by an ion chromatograph after the volume of the absorption liquid is fixed. However, this method has the following significant drawbacks in practical applications: The absorption efficiency is limited, and particularly, the absorption effect on soluble gases such as hydrogen chloride (HCl) is still good when deionized water is used as an absorption liquid, but the absorption efficiency on halides with lower solubility such as chlorine (Cl 2) is poor (about 23.4% is reported in literature), so that the measurement result of total halides is seriously low, and the quality of hydrogen cannot be truly reflected. The operation is complicated, and the human error is large, and the whole sampling, volume fixing and transferring processes completely depend on manual operation, including the addition of absorption liquid, the control of sampling time length, the manual volume fixing and transferring after sampling and the like. Complicated steps, and is easy to introduce accidental errors due to operator differences, thereby affecting the repeatability and accuracy of detection. The sampling process cannot be monitored in real time, namely the problems that the traditional device lacks a process monitoring means, whether sampling is complete, absorption liquid is saturated, whether leakage exists or not and the like cannot be known in the process, and the sampling process cannot be judged only after analysis is finished, so that invalid sampling and resource waste can be caused. The sensitivity of the trace analysis is insufficient, namely, for trace halide detection below 0.05 mu mol/mol, the trace components can escape due to insufficient gas-liquid contact in the traditional single-stage absorption device, and the detection limit of the method is difficult to further reduce. Thus, there is a need for improved techniques and apparatus for efficient, automatic, high precision sampling and for trace halide determination. Disclosure of Invention In order to solve the technical problems in the background art, the invention provides an automatic sampling analysis system and method for measuring trace halide in hydrogen. The invention provides an automatic sampling analysis system for measuring trace halide in hydrogen, which comprises the following components: the gas source interface is used for being connected with a hydrogen source; The gas inlet of the gas flow control and metering unit is connected with the gas source interface and is used for controlling the flow of hydrogen and metering the volume of hydrogen; The sampling absorption module comprises a plurality of gas absorption units which are connected in series, wherein alkaline absorption liquid is contained in each gas absorption unit, and an air inlet of the sampling absorption module is connected with an air outlet of the gas flow control and metering unit; The automatic control and sample injection module comprises a controller, a liquid conveying unit, a valve unit and a constant volume unit, wherein the controller is electrically connected with the liquid conveying unit and the valve unit, the liquid conveying unit is respectively in fluid connection with each gas absorbing unit and the constant volume unit through the valve unit, the controller is configured to control the liquid conveying unit and the valve unit to automatically inject the alkaline absorbing liquid into each gas absorbing unit, and after sampling is finished, the absorbing liquid in each gas absorbing unit is automatically combined and transferred into the constant volume unit for constant volume. Preferably, the sampling absorption module comprises at least three stages of gas absorption units connected in series, the gas absorption units adopt gas washing bottles made of perfluoroalkoxyalkane, and the gas inlet and the gas outlet of each gas washing bottle are sequentially connected in series through a p