Gas chromatograph for analyzing krypton and xenon in liquid oxygen and analysis method thereof

Abstract

The invention provides a gas chromatographic analysis method for krypton and xenon in liquid oxygen. The gas chromatographic analysis method comprises the following steps: performing sample analysis according to instrument configuration and operation parameters, taking high-purity liquid oxygen as a sample under the condition of stable process production operation, analyzing the content of krypton and xenon in the liquid oxygen, and recording the content of krypton and xenon. By additionally arranging the deoxidation column, the accuracy of measuring the krypton and xenon contents in the liquid oxygen product is improved, the purpose of prolonging the service life of a thermal conductivity cell detector is achieved, a working condition operation reference basis is provided for the device, and the operation efficiency is improved. The analysis result of the analysis method is accurate, and instrument configuration is simplified.

Description

Technical Field

[0001] The invention belongs to the field of chromatographic analysis, and in particular relates to a gas chromatograph used for analyzing krypton and xenon in liquid oxygen and an analysis method thereof. Background Art

[0002] Krypton and xenon are rare gases with extremely small reserves in nature and are important industrial gases in the national economy. With the development of society and technology, the demand for the above two gases continues to grow. The main reason is that the application fields of krypton and xenon are becoming more and more extensive. They are not only used in the traditional lighting industry, but also in recent years, their applications in building doors and windows, flat-screen TVs, electronic chips, space, satellites and the medical industry are also on the rise. At present, the production method of krypton and xenon is mainly to separate and extract them from the air through large-scale air separation equipment. The process flow is to first separate the air into liquid nitrogen and liquid oxygen, and then further extract the initially enriched krypton and xenon from the liquid oxygen, and obtain high-purity krypton and xenon products through repeated distillation. Inventor's company 105000m 3 / h air separation production of liquid oxygen sampling chromatographic analysis, krypton and xenon content reached more than 1000ppm, which belongs to product sales and can create production benefits. Therefore, the krypton and xenon content in liquid oxygen needs to be accurately measured to guide the setting of subsequent process parameters and the adjustment of process flow, to maximize the benefits for the company, and has important guiding significance for the operation of air separation units and the monitoring of krypton and xenon content during the process.

[0003] With the development of society and technology, the demand for krypton and xenon gases continues to grow. At present, the production method of krypton and xenon is mainly to separate and extract them from the air through large-scale air separation equipment. Therefore, the krypton and xenon content in liquid oxygen needs to be accurately measured to guide the setting of subsequent process parameters and the adjustment of process flow. Since oxygen and krypton have similar properties, the separation degree of oxygen and krypton is poor. Therefore, the accurate quantification of krypton and xenon in liquid oxygen is of great guiding significance for the operation of air separation equipment and the monitoring of krypton and xenon content in the process, and also has guiding significance for the pricing of products.

[0004] Patent application CN116242936A discloses a gas chromatograph and analysis method for krypton and xenon analysis in liquid oxygen. Krypton and xenon analysis in liquid oxygen is carried out by using three valves and four columns as separation technology carriers, adopting positive blowing and center cutting technology to improve the separation of chromatographic peaks, adopting small volume quantitative loop sampling, using highly sensitive helium ionization detector and wide range logarithmic amplifier to collect signals, so that components Kr, Xe and harmful impurities CH4 and N2O in the process of purifying krypton and xenon from liquid oxygen are linear within the concentration range. It is mainly equipped with a ten-way valve, two six-way valves, 0.2mL quantitative loop, two Propark-Q filling columns, two 5A molecular sieve columns, and a helium ionization detector. By controlling the carrier gas pressure, the switching time of the ten-way valve and the six-way valve, the center cutting is realized, and a large amount of oxygen, the main component of oxygen, is vented. The components to be tested are sent to the helium ionization detector for detection by switching the valve ( Figure 6 ). The analysis method requires precise flow control and accurate valve switching time during operation. Once the column efficiency changes, it needs to be adjusted, which requires heavy post-maintenance and processing. Moreover, if the column efficiency is not found to decrease during the long-term analysis, it will lead to problems such as small final results.

[0005] Therefore, it is an urgent problem to be solved by those skilled in the art to improve the gas chromatograph and analysis method for krypton-xenon analysis in liquid oxygen so that the analysis results are accurate and the instrument configuration is simplified. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide an improved gas chromatograph for analyzing krypton and xenon in liquid oxygen and an analysis method thereof, which has accurate analysis results and simplified instrument configuration.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] In a first aspect, the present invention provides a gas chromatography analysis method for krypton and xenon in liquid oxygen, wherein:

[0009] The instrument configuration and reagents used are as follows:

[0010] 1) Equipment model: Gas chromatograph GC590 from PerkinElmer, USA

[0011] 2) Detector: TCD thermal conductivity cell detector

[0012] 3) Analytical column: 5A molecular sieve column, 401 deoxygenation column

[0013] 4) Standard gas: Krypton 910ppm, Xenon 60ppm, Nitrogen as balance gas

[0014] 5) Inlet: Packing column inlet

[0015] 6) Carrier gas pressure: 0.4Mpa

[0016] 7) Injection method: gas six-way valve injection

[0017] 8) Quantitative loop: 2mL

[0018] 9) Gas flow control device: electronic pressure control device (programmed pneumatic control (PPC))

[0019] 10) Sample analysis process

[0020] The sample is replaced by the quantitative loop when the six-way valve is reset. The sample enters from interface 1 and exits from interface 6. After passing through the quantitative loop, the sample enters from interface 3 and exits from interface 2, and is discharged from the six-way valve to the waste recovery system. After the quantitative loop is fully replaced, the six-way valve is switched to the injection state. At this time, the carrier gas carrying the sample in the quantitative loop enters from interface 5, and the interface 6 is connected to the quantitative loop inlet. The quantitative loop outlet is connected to interface 3 and interface 4, and then enters the 401 deoxygenation column to remove oxygen from the sample. The deoxygenated sample will enter the 5A molecular sieve column for krypton-xenon separation, and finally detected by the thermal conductivity cell detector. The data processing system (TotalChrom workstation) is used to obtain a complete chromatogram, thereby obtaining an accurate krypton-xenon component content.

[0021] According to the gas chromatography analysis method for krypton and xenon in liquid oxygen of the present invention,

[0022] The instrument operating parameters are as follows:

[0023] 1) Column box / injection port program temperature step setting: initial temperature 80°C, maintained for 2 minutes, then increased to 120°C at a heating rate of 20°C / min, maintained for 2 minutes, equilibrium time 0.5min, and operation end time 6min;

[0024] 2) Detector temperature: 100°C;

[0025] 3) Carrier gas flow rate: 25 mL / min;

[0026] 4) Valve switching time: 0.00min to start operation, and the valve switches to close in 0.8min.

[0027] According to the gas chromatography analysis method for krypton and xenon in liquid oxygen of the present invention,

[0028] The calibration curve was established as follows:

[0029] 1) Use krypton standard gas as the mother gas and nitrogen as the diluent gas, and use an online diluter to dilute to five points with different contents of 0ppm, 50ppm, 100ppm, 500ppm, and 900ppm, as shown in the following table. Use the external standard method to prepare the analytical standard curve. The krypton standard gas standard curve is as follows: Figure 2 As shown:

[0030]

[0031] 2) Use xenon standard gas as the mother gas and nitrogen as the diluent gas, and use an online diluter to dilute to five points with different contents of 0ppm, 10ppm, 20ppm, 40ppm, and 60ppm, as shown in the following table. Use the external standard method to prepare the analytical standard curve. The standard curve of xenon standard gas is as follows: Figure 3 As shown:

[0032]

[0033] According to the gas chromatography analysis method for krypton and xenon in liquid oxygen of the present invention,

[0034] The accuracy and precision were determined as follows:

[0035] After the standard curve was established, the standard gas of krypton 20ppm and xenon 40ppm was used to repeat the measurement 5 times in parallel. The results of the repeated measurements are shown in the following table:

[0036]

[0037] It can be seen from the data in this table that through accuracy and precision measurement, the standard deviation is less than 2%, the maximum error is less than 0.5%, the repeatability is good, and the results meet the standard requirements.

[0038] According to the gas chromatography analysis method for krypton and xenon in liquid oxygen of the present invention,

[0039] The samples were assayed as follows:

[0040] According to the above instrument configuration and operating parameters, sample analysis is carried out. When the process production is running smoothly, high-purity liquid oxygen is taken as a sample, the krypton and xenon content therein is analyzed, and the krypton and xenon content is recorded.

[0041] According to the gas chromatography analysis method for krypton and xenon in liquid oxygen of the present invention,

[0042] The result is calculated as follows:

[0043] 1) Calculation of correction factor

[0044] Correction factor f for component i i , calculated as follows:

[0045] f i =c i / A i

[0046] Where:

[0047] Ai : The peak area of ​​component i in the standard sample;

[0048] c i : The content of component i in the standard sample;

[0049] 2) Content w of component i i , unit ppm, calculated as follows:

[0050] w i =f i ×A2

[0051] Where:

[0052] A2: peak area corresponding to component i;

[0053] f i : Correction factor for component i.

[0054] According to the gas chromatography analysis method of krypton and xenon in liquid oxygen described in the present invention, wherein the 401 deoxygenation column is selected from a 401 nickel catalyst deoxygenation column, a 401 copper catalyst deoxygenation column or a 401 manganese catalyst deoxygenation column, preferably a 401 nickel catalyst deoxygenation column. In a second aspect, the present invention provides a gas chromatograph for the analysis of krypton and xenon in liquid oxygen, comprising: an injection system, a carrier gas system, a separation system, a temperature control system and a detection system, wherein the injection system comprises a six-way valve and a quantitative loop (2.0cc / 2.0mL); the carrier gas system is used to carry the sample, flowing through the vaporization chamber, the chromatographic column, and the detector to complete the separation and analysis of the sample; the temperature control system is used to keep the temperature in the chromatographic column constant and prevent temperature fluctuations and disturbances; the separation system comprises a 401 deoxygenation column and a 5A molecular sieve; the detection system comprises a thermal conductivity cell detector (TCD).

[0055] According to the gas chromatograph for krypton and xenon analysis in liquid oxygen of the present invention, the sample is replaced by the quantitative loop when the six-way valve is reset, the sample enters from the interface 1 and exits from the interface 6, enters from the interface 3 and exits from the interface 2 after passing through the quantitative loop, and is discharged from the six-way valve to the waste recovery system; after the quantitative loop is fully replaced, the six-way valve is switched to the injection state, at this time, the carrier gas carrying the sample in the quantitative loop enters from the interface 5, the interface 6 is connected to the quantitative loop inlet, the quantitative loop outlet is connected to the interface 3 and exits from the interface 4, and then enters the 401 deoxygenation column to remove oxygen from the sample, and the deoxygenated sample will enter the 5A molecular sieve column for krypton and xenon separation, and finally detected by the thermal conductivity cell detector, and a complete chromatogram is obtained by using the data processing system (TotalChrom workstation), so as to obtain an accurate krypton and xenon component content.

[0056] In the instrument configuration and analysis method previously developed by the inventor, krypton and xenon in liquid oxygen are mostly analyzed using a gas chromatograph equipped with a thermal conductivity detector, a 5A molecular sieve chromatographic column, and a six-way valve ( Figure 7), and the external standard method was used for quantification. Since only 5A molecular sieve was used as the analytical column, and the molecular sieve analytical column responded to oxygen, krypton, and xenon, and peaks were produced in the data processing. Since oxygen and krypton have similar properties, they are difficult to separate. In the actual analysis process, the chromatographic peak effect is very good when using standard gas calibration ( Figure 8 ), but in the subsequent analysis of the sample, it was found that the oxygen peak was very large, and the oxygen peak basically covered the krypton peak ( Fig. 9 ), the main reason for this phenomenon is that oxygen is high-purity oxygen with a large content, a large peak shape, and a long retention time, so the peak area of ​​krypton cannot be accurately measured, which in turn affects the accurate quantification of krypton.

[0057] Therefore, the existing instrument configuration and analysis method have the following technical problems to be solved:

[0058] 1. Oxygen masks the chromatographic peak of krypton, making it impossible to accurately quantify

[0059] When using a 5A molecular sieve column to determine the krypton and xenon content in liquid oxygen products, the oxygen content is too high and the peak tailing is severe, which will mask the krypton peak, resulting in poor classification and inability to obtain the accurate peak area of ​​krypton. When the correction factor is determined for external standard quantitative analysis, the peak area of ​​the target component is the only variable for quantification, which affects the final krypton content. Therefore, solving the phenomenon of oxygen masking the krypton peak is the key.

[0060] 2. The oxygen in the liquid oxygen product will damage the hot wire of the thermal conductivity cell detector

[0061] Oxygen will affect the service life of the thermal conductivity element, reduce the sensitivity of the detector, and even cause resistance changes or breakage. Liquid oxygen products contain more than 99% oxygen. When analyzing, we use a 2mL quantitative loop. The amount of sample entering the chromatographic analysis system is large, which will have a certain impact on the thermal conductivity cell detector. If the injection volume is too small, it will cause the TCD response to decrease, affecting the accuracy of the analysis results.

[0062] In response to the above technical problems, the inventors tried to remove oxygen before the sample entered the separation system to reduce the oxygen peak area, avoid oxygen covering the krypton peak, and better protect the thermal conductivity detector, which can completely solve the above problems in the actual analysis process. However, the instrument configuration is relatively complex, the analysis process is relatively cumbersome, and the instrument configuration cost is relatively high. In order to achieve the separation effect achieved by the above instrument configuration, the instrument needs to be modified. To this end, the inventors optimized the instrument configuration based on the existing instrument configuration and analysis method to solve the above technical problems. The analysis method of the present invention uses a gas chromatograph to determine the content of krypton and xenon in liquid oxygen, and uses an external standard method for quantification. The inventors found that the use of a 401 deoxygenation column can directly remove impurity oxygen in gases such as nitrogen, hydrogen, and helium at room temperature. The residual oxygen content in the purified gas is less than 10 mL / L, and the deoxygenation capacity can generally reach 15 mg / g. The deoxidizer changes from green to dark brown after absorbing oxygen, and has an intuitive color change indication function. It can be regenerated and reused after failure. When nitrogen: hydrogen = 5:1, the column box temperature is kept at 250°C for 6 hours, and the liquid oxygen sample can be fed about 2,000 times after regeneration. Therefore, it was finally determined to add a 401 deoxygenation column before the analytical column to remove oxygen from the sample, and then enter the separation system and the detection system in turn, so as to achieve the purpose of accurately quantifying krypton and extending the life of the thermal conductivity cell detector.

[0063] In summary, the beneficial effects of the present invention are as follows: the present invention determines the contents of krypton and xenon in the liquid oxygen product by means of a gas chromatograph equipped with a deoxygenation column, thus overcoming the problem that the component krypton cannot be accurately quantified and that oxygen in the sample shortens the life of the thermal conductivity cell detector; in actual sample analysis, after the deoxygenation column is installed, the peak effect is good and the separation degree is high, and there is no interference between the components, thus avoiding the measurement errors caused by the oxygen peak in the liquid oxygen sample covering the krypton peak and the influence of oxygen on the resistance of the hot wire of the thermal conductivity cell detector. Finally, the accuracy of the determination of the krypton and xenon contents in the liquid oxygen product is improved by installing a deoxygenation column, and the purpose of extending the life of the thermal conductivity cell detector is achieved, and a reference basis for the operating conditions of the device is provided, thereby improving the operating efficiency. The analysis results of the analysis method of the present invention are accurate, and the instrument configuration is simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 The operating valve circuit diagram of the sample analysis process of the present invention is shown.

[0065] Figure 2 The standard curve of krypton standard gas of the present invention is shown.

[0066] Figure 3 The standard curve of xenon standard gas according to the present invention is shown.

[0067] Figure 4 The analysis spectrum of krypton and xenon standard gases after the deoxidation column is added in the present invention is shown.

[0068] Figure 5The following is a spectrum showing the analysis of krypton and xenon in the liquid oxygen product after the deoxygenation column is added according to the present invention.

[0069] Figure 6 The operating valve diagram of the krypton-xenon analysis process in liquid oxygen in the prior art is shown.

[0070] Figure 7 The operating valve diagram of the liquid oxygen sample analysis process in the inventor's early solution is shown.

[0071] Figure 8 Shown are the analysis spectra of krypton and xenon standard gases in the inventor's early proposal.

[0072] Fig. 9 The figure shows the analytical spectrum of krypton and xenon in liquid oxygen product in the inventor's early scheme. DETAILED DESCRIPTION

[0073] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0074] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0075] The 401 deoxidation column used in the following examples of the present invention is a 401 nickel catalyst deoxidation column purchased from Dalian Shengmei Chemical New Technology Co., Ltd.

[0076] Example 1 Gas Chromatographic Analysis of Krypton and Xenon in Liquid Oxygen

[0077] 1. Instrument configuration and reagents used:

[0078] 1) Equipment model: Gas chromatograph GC590 from PerkinElmer, USA

[0079] 2) Detector: TCD thermal conductivity cell detector

[0080] 3) Analytical column: 5A molecular sieve column, 401 deoxygenation column

[0081] 4) Standard gas: Krypton 910ppm, Xenon 60ppm, Nitrogen as balance gas

[0082] 5) Inlet: Packing column inlet

[0083] 6) Carrier gas pressure: 0.4Mpa

[0084] 7) Injection method: gas six-way valve injection

[0085] 8) Quantitative loop: 2mL

[0086] 9) Gas flow control device: electronic pressure control device (programmed pneumatic control)

[0087] 10) Sample analysis process

[0088] The sample is replaced by the quantitative loop when the six-way valve is reset. The sample enters from interface 1 and exits from interface 6. After passing through the quantitative loop, the sample enters from interface 3 and exits from interface 2, and is discharged from the six-way valve to the waste recovery system. After the quantitative loop is fully replaced, the six-way valve is switched to the injection state. At this time, the carrier gas carrying the sample in the quantitative loop enters from interface 5, and the interface 6 is connected to the quantitative loop inlet. The quantitative loop outlet is connected to interface 3 and interface 4, and then enters the 401 deoxygenation column to remove oxygen from the sample. The deoxygenated sample will enter the 5A molecular sieve column for krypton-xenon separation, and finally detected by the thermal conductivity cell detector. The data processing system (TotalChrom workstation) is used to obtain a complete chromatogram, thereby obtaining an accurate krypton-xenon component content.

[0089] The operation valve circuit diagram of the sample analysis process is shown in Figure 1 .

[0090] 2. Instrument operating parameters:

[0091] 1) Column box / injection port program temperature step setting: initial temperature 80°C, maintained for 2 minutes, then increased to 120°C at a heating rate of 20°C / min, maintained for 2 minutes, equilibrium time 0.5min, and operation end time 6min;

[0092] 2) Detector temperature: 100°C;

[0093] 3) Carrier gas flow rate: 25 mL / min;

[0094] 4) Valve switching time: 0.00min to start operation, and the valve switches to close in 0.8min.

[0095] 3. Establish the calibration curve:

[0096] 1) Use krypton standard gas as the mother gas and nitrogen as the diluent gas, and dilute it with an online diluter to five points with different contents of 0ppm, 50ppm, 100ppm, 500ppm, and 900ppm, as shown in Table 1. Use the external standard method to prepare the analytical standard curve. The krypton standard gas standard curve is as follows: Figure 2 As shown:

[0097] Table 1

[0098]

[0099] 2) Using xenon standard gas as the mother gas and nitrogen as the diluent gas, dilute with an online diluter to five points with different contents of 0ppm, 10ppm, 20ppm, 40ppm, and 60ppm, as shown in Table 2, and prepare the analytical standard curve using the external standard method. The standard curve of xenon standard gas is as follows: Figure 3 As shown:

[0100] Table 2

[0101]

[0102]

[0103] From the above standard curve data, it can be seen that the online dilution effect is good, the standard curve is very linear, and it fully meets the analysis standard requirements. The instrument status and configuration have high sensitivity, good selectivity, and the separation effect achieves complete separation. There is no interference between the components, such as Figure 4 Krypton and xenon standard gas analysis spectra after adding deoxygenation column Figure 5 After the deoxygenation column is installed, the analysis spectrum of krypton and xenon in the liquid oxygen product meets the actual analysis requirements and has been well applied in practical work.

[0104] 4. Accuracy and precision determination:

[0105] After the standard curve was established, the standard gas of krypton 20ppm and xenon 40ppm was used to repeat the measurement 5 times in parallel. The results of the repeated measurements are shown in Table 3:

[0106] Table 3

[0107]

[0108] It can be seen from the data in Table 3 that through the accuracy and precision measurement, the standard deviation is less than 2%, the maximum error is less than 0.5%, the repeatability is good, and the results meet the standard requirements.

[0109] 5. Sample determination:

[0110] According to the above instrument configuration and operating parameters, sample analysis is carried out. When the process production is running smoothly, high-purity liquid oxygen is taken as a sample, the krypton and xenon content therein is analyzed, and the krypton and xenon content is recorded.

[0111] 6. Calculation of results:

[0112] 1) Calculation of correction factor

[0113] Correction factor f for component i i , calculated as follows:

[0114] f i =c i / A i

[0115] Where:

[0116] A i : The peak area of ​​component i in the standard sample;

[0117] c i : The content of component i in the standard sample;

[0118] 2) Content w of component i i , unit ppm, calculated as follows:

[0119] w i =f i ×A2

[0120] Where:

[0121] A2: peak area corresponding to component i;

[0122] f i : Correction factor for component i.

[0123] Example 2 Determination of krypton and xenon content in liquid oxygen product of Yulin Company's air separation unit

[0124] The actual sample analysis was performed according to the configuration and operation parameters in Example 1 of the present invention. High-purity liquid oxygen was used as a sample when the process production was running smoothly, and the krypton and xenon content therein was analyzed. The measurement data for five consecutive days are shown in Table 4:

[0125] Table 4

[0126]

[0127] Except for not adding the deoxidation column, other configurations and operating parameters are the same as those in Example 1, and actual sample analysis is performed. When the process production is running smoothly, high-purity liquid oxygen is taken as a sample, and the krypton and xenon content therein is analyzed. The measured data for five consecutive days are shown in Table 5:

[0128] Table 5

[0129]

[0130] It can be seen from the above data that when the method of the present invention is used to analyze the krypton and xenon contents in liquid oxygen products, the krypton content is not affected by oxygen, and accurate quantification can be achieved with stable analysis data, which has a good guiding significance for the smooth operation of on-site production equipment.

Claims

1. A gas chromatography analysis method for krypton and xenon in liquid oxygen, wherein: The instrument configuration and reagents used are as follows: 1) Equipment model: Gas chromatograph GC590 from PerkinElmer, USA 2) Detector: TCD thermal conductivity cell detector 3) Analytical column: 5A molecular sieve column, 401 deoxygenation column 4) Standard gas: Krypton 910ppm, Xenon 60ppm, Nitrogen as balance gas 5) Inlet: Packing column inlet 6) Carrier gas pressure: 0.4Mpa 7) Injection method: gas six-way valve injection 8) Quantitative loop: 2mL 9) Gas flow control device: electronic pressure control device 10) Sample analysis process The sample is replaced by the quantitative loop when the six-way valve is reset. The sample enters from interface 1 and exits from interface 6. After passing through the quantitative loop, the sample enters from interface 3 and exits from interface 2, and is discharged from the six-way valve to the waste recovery system. After the quantitative loop is fully replaced, the six-way valve is switched to the injection state. At this time, the carrier gas carrying the sample in the quantitative loop enters from interface 5, and the interface 6 is connected to the quantitative loop inlet. The quantitative loop outlet is connected to interface 3 and interface 4, and then enters the 401 deoxygenation column to remove oxygen from the sample. The deoxygenated sample will enter the 5A molecular sieve column for krypton-xenon separation, and will eventually be detected by a thermal conductivity cell detector. A complete chromatogram is obtained using a data processing system, thereby obtaining an accurate krypton-xenon component content.

2. The gas chromatography analysis method for krypton and xenon in liquid oxygen according to claim 1, wherein: The instrument operating parameters are as follows: 1) Column box / injection port program temperature step setting: initial temperature 80°C, maintained for 2 minutes, then increased to 120°C at a heating rate of 20°C / min, maintained for 2 minutes, equilibrium time 0.5min, and operation end time 6min; 2) Detector temperature: 100°C; 3) Carrier gas flow rate: 25 mL / min; 4) Valve switching time: 0.00min to start operation, and the valve switches to close in 0.8min.

3. The gas chromatography analysis method for krypton and xenon in liquid oxygen according to claim 1 or 2, wherein: The gas chromatography analysis method for krypton and xenon in liquid oxygen includes establishing a krypton standard gas calibration curve: Krypton standard gas was used as the mother gas, nitrogen was used as the diluent gas, and the sample was diluted to five points with different contents of 0ppm, 50ppm, 100ppm, 500ppm, and 900ppm using an online diluter. The analytical standard curve was prepared using the external standard method.

4. The gas chromatography analysis method for krypton and xenon in liquid oxygen according to any one of claims 1 to 3, wherein: The gas chromatography analysis method for krypton and xenon in liquid oxygen includes establishing a xenon standard gas calibration curve: Xenon standard gas was used as the mother gas, nitrogen was used as the diluent gas, and the sample was diluted to five different concentrations of 0ppm, 10ppm, 20ppm, 40ppm, and 60ppm using an online diluter. The analytical standard curve was prepared using the external standard method. 。 5. The gas chromatography analysis method for krypton and xenon in liquid oxygen according to any one of claims 1 to 4, wherein: The gas chromatography analysis method for krypton and xenon in liquid oxygen includes the following accuracy and precision determination: After the standard curve was established, the measurement was repeated five times in parallel using standard gases of 20 ppm krypton and 40 ppm xenon; Through accuracy and precision measurement, the standard deviation is less than 2%, the maximum error is less than 0.5%, and the repeatability is good.

6. The gas chromatography analysis method for krypton and xenon in liquid oxygen according to any one of claims 1 to 5, wherein: The gas chromatography analysis method for krypton and xenon in liquid oxygen includes sample determination: According to the above instrument configuration and operating parameters, sample analysis is carried out. When the process production is running smoothly, high-purity liquid oxygen is taken as a sample, the krypton and xenon content therein is analyzed, and the krypton and xenon content is recorded.

7. The gas chromatography analysis method for krypton and xenon in liquid oxygen according to any one of claims 1 to 6, wherein: The gas chromatography analysis method for krypton and xenon in liquid oxygen includes the calculation of the results: 1) Calculation of correction factor Correction factor f for component i i , calculated as follows: f i =c i / A i Where: A i : The peak area of ​​component i in the standard sample; c i : The content of component i in the standard sample; 2) Content w of component i i , unit ppm, calculated as follows: w i =f i ×A2 Where: A2: peak area corresponding to component i; f i : Correction factor for component i.

8. A gas chromatograph for analyzing krypton and xenon in liquid oxygen, comprising: Injection system, carrier gas system, separation system, temperature control system and detection system.

9. The gas chromatograph for analyzing krypton and xenon in liquid oxygen according to claim 8, wherein: The injection system includes a six-way valve and a quantitative loop; the carrier gas system is used to carry the sample and flow through the vaporization chamber, chromatographic column, and detector to complete the separation and analysis of the sample; the temperature control system is used to keep the temperature in the chromatographic column constant and prevent temperature fluctuations and disturbances; the separation system includes a 401 deoxygenated column and a 5A molecular sieve; the detection system includes a thermal conductivity detector (TCD).

10. The gas chromatograph for analyzing krypton and xenon in liquid oxygen according to claim 8 or 9, wherein: The sample is replaced by a quantitative loop when the six-way valve is reset. The sample enters from the interface (1) and exits from the interface (6). After passing through the quantitative loop, the sample enters from the interface (3) and exits from the interface (2). The sample is discharged from the six-way valve to a waste recovery system. After the quantitative loop is fully replaced, the six-way valve is switched to an injection state. At this time, the carrier gas carrying the sample in the quantitative loop enters from the interface (5), the interface (6) is connected to the inlet of the quantitative loop, the outlet of the quantitative loop is connected to the inlet of the quantitative loop, and the inlet of the quantitative loop is connected to the interface (3) and the outlet of the quantitative loop is connected to the inlet of the interface (4). The sample then enters a 401 deoxygenation column to remove oxygen from the sample. The deoxygenated sample enters a 5A molecular sieve column for krypton-xenon separation. The sample is finally detected by a thermal conductivity cell detector. A complete chromatogram is obtained by using a data processing system, thereby obtaining an accurate krypton-xenon component content.

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