Method for analyzing trace or trace impurities in various high-purity gases

Abstract

The invention discloses a method for analyzing trace or trace impurities in various high-purity gases. The method comprises the following steps: firstly, determining that the high-purity gas to be detected is one of high-purity hydrogen, high-purity oxygen, high-purity nitrogen and high-purity argon; respectively filling the high-purity gas to be detected with a set volume into the two detection branches; through separation of a pre-separation column and a main separation column in the first detection branch and switching of a ten-way valve and a six-way valve, main components, CO2, C2H2, C2H4 and C2H6 in the to-be-detected high-purity gas are emptied, and residual mixed gas A and CH4 are separated and conveyed to a PDHID detector for detection; through separation of a pre-separation column and a main separation column in the second detection branch and switching of a six-way valve, main components, mixed gas A and CH4 in the to-be-detected high-purity gas are emptied, and residual CO2, C2H2, C2H4 and C2H6 are separated and conveyed to a PDHID detector for detection. Detection results on the two detection branches are combined to obtain a final analysis result, the purposes of simplifying the operation process and reducing the analysis cost are achieved, the peak area reproducibility (n is equal to 6) is smaller than or equal to 1%, and the lowest detection limit of each impurity is smaller than 20 ppb.

Description

Technical Field

[0001] The invention relates to the field of gas analysis, and in particular to a method for analyzing trace or micro-amount impurities in a variety of high-purity gases. Background Art

[0002] With the continuous release of industrial capacity, high-purity gas is used as raw gas, protective gas, and fuel gas in various fields such as industrial manufacturing, coal chemical industry, energy chemical industry, organic chemical synthesis, electronics, and aerospace, and the relationship between its purity and product quality has gradually become prominent. Since the main components of high-purity gas have large tailing peaks, and some impurity peaks appear on the tail of the main peak, separation is difficult and the minimum detection limit cannot be guaranteed.

[0003] The existing methods for analyzing trace or trace impurities in high-purity hydrogen, high-purity argon, high-purity oxygen, and high-purity nitrogen mainly use gas chromatography combined with a pulsed discharge helium ionization detector (PDHID detector). Existing equipment can only detect trace or trace impurities in a single high-purity gas. For example, the valve path analysis system suitable for trace or trace impurities in high-purity hydrogen cannot simultaneously meet the requirements for the detection of trace or trace impurities in high-purity oxygen and high-purity nitrogen. The valve path analysis system suitable for trace or trace impurities in high-purity oxygen and nitrogen cannot simultaneously meet the requirements for the detection of trace or trace impurities in high-purity hydrogen. It is even more difficult to separate these four high-purity gases using a set of analysis systems and obtain accurate analysis and detection.

[0004] The prior art discloses a technical solution for detecting impurities in high-purity oxygen in the optical fiber industry using DID gas chromatography. To simultaneously complete the detection of trace or trace impurities in four high-purity gases, namely, high-purity hydrogen, high-purity argon, high-purity oxygen, and high-purity nitrogen, multiple instruments or changes to the system flow path, valve replacement, and chromatographic column replacement are required for multiple injections and analyses, resulting in low analysis efficiency, cumbersome operations, and high analysis costs. Summary of the invention

[0005] In view of the above-mentioned defects in the prior art, a method for analyzing trace or trace impurities in a variety of high-purity gases is provided. Two detection branches are used to detect trace or trace impurities in one of four high-purity gases, thereby simplifying the operation process and reducing the analysis cost.

[0006] The technical solution adopted by the present invention to solve the above technical problems is:

[0007] A method for analyzing trace or micro-amount impurities in a variety of high-purity gases, characterized by:

[0008] Confirm that the high-purity gas to be tested is one of high-purity hydrogen, high-purity oxygen, high-purity nitrogen, and high-purity argon;

[0009] The high-purity gas to be tested is introduced, and the set volume of the high-purity gas to be tested is respectively charged into the two detection branches through the switching of the ten-way valve;

[0010] Through the separation of the pre-separation column and the main separation column in the first detection branch, and the switching of the ten-way valve and the six-way valve, the main components, CO2, C2H2, C2H4, and C2H6 in the high-purity gas to be tested are emptied, and the remaining mixed gas A and CH4 are separated and transported to the PDHID detector for detection;

[0011] After separation of the pre-separation column and the main separation column in the second detection branch and switching of the six-way valve, the main component, mixed gas A, and CH4 in the high-purity gas to be tested are emptied, and the remaining CO2, C2H2, C2H4, and C2H6 are separated and transported to the PDHID detector for detection;

[0012] Among them, when the high-purity gas to be tested is high-purity hydrogen, the mixed gas A refers to a mixture of O2, N2 and CO, and the main component refers to hydrogen; when the high-purity gas to be tested is high-purity argon or high-purity oxygen, the mixed gas A refers to a mixture of H2, N2 and CO, and the main component refers to argon or oxygen respectively; when the high-purity gas to be tested is high-purity nitrogen, the mixed gas A refers to a mixture of O2, H2 and CO, and the main component refers to nitrogen.

[0013] According to the above technical solution, the method adopts a four-valve six-column valve circuit system, including a test gas intake assembly, a first detection branch, and a second detection branch;

[0014] The test gas inlet assembly includes a ten-way valve A, and the high-purity gas to be tested enters the ten-way valve A. By switching the state of the ten-way valve A, the high-purity gas to be tested is sequentially sent to the first detection branch and the second detection branch through the switching of the state of the ten-way valve A;

[0015] The first detection branch includes a ten-way valve B, a first pre-separation column and a second pre-separation column arranged on the ten-way valve B, a six-way valve a, a first main separation column arranged between the ten-way valve B and the six-way valve a, and a second main separation column arranged between the six-way valve a and the PDHID detector; according to the type of high-purity gas to be tested, the high-purity gas to be tested is controlled to pass into the first pre-separation column or the second pre-separation column by switching the state of the ten-way valve B, and part of the high-purity hydrogen, CO2, C2H2, C2H4, and C2H6 are emptied during the analysis of high-purity hydrogen; by switching the six-way valve a once or multiple times, the remaining high-purity hydrogen is emptied when analyzing hydrogen, or the high-purity gas, CO2, C2H2, C2H4, and C2H6 are emptied when analyzing high-purity oxygen, nitrogen, and argon, and the mixed gas A and CH4 are transported to the second main separation column;

[0016] The second detection branch includes a six-way valve b, a third pre-separation column arranged in front of the six-way valve b, and a third main separation column arranged at the rear of the six-way valve; by switching the six-way valve b, the main component, the mixed gas A, and CH4 are emptied, and CO2, C2H2, C2H4, and C2H6 are transported to the third main separation column;

[0017] All pre-separation columns and main separation columns are used to separate the introduced gas and output it in different time periods according to its components. The output time periods of some components overlap.

[0018] According to the above technical scheme, the first pre-separation column adopts a high specific surface area carbon molecular sieve column; the second pre-separation column, the first main separation column, and the second main separation column all adopt molecular sieve analysis columns, preferably a 13X molecular sieve analysis column; the third pre-separation column and the third main separation column adopt a polymer porous microsphere analysis column.

[0019] According to the above technical solution, when testing high-purity hydrogen,

[0020] In the first detection branch, the ten-way valve A is switched to deliver a quantitative amount of high-purity gas to be detected to the first pre-separation column;

[0021] Part of the main components and CO2, C2H2, C2H4, and C2H6 are emptied by switching the ten-way valve B, and then the remaining main components are emptied by switching the six-way valve a;

[0022] In the second detection branch, the ten-way valve A is switched to deliver a quantitative amount of high-purity gas to be detected to the second pre-separation column;

[0023] The main component, mixed gas A, and CH4 are exhausted by switching the six-way valve.

[0024] According to the above technical solution, when testing high purity oxygen, nitrogen, or argon;

[0025] In the first detection branch, the ten-way valve A is switched to deliver a quantitative amount of high-purity gas to be tested to the first pre-separation column;

[0026] The high-purity gas to be tested is delivered to the first main separation column by switching the ten-way valve B, and CO2, C2H2, C2H4, C2H6 and the main component are evacuated by multiple switching of the six-way valve a;

[0027] In the second detection branch, the ten-way valve A is switched to deliver a quantitative amount of high-purity gas to be tested to the second pre-separation column;

[0028] The main component, mixed gas A, and CH4 are exhausted by switching the six-way valve.

[0029] According to the above technical solution, the switching time of each valve is determined as follows:

[0030] The high-purity gas to be tested is introduced into the valve path system of four valves and six columns by full injection to obtain a first gas chromatogram;

[0031] According to the first gas chromatogram, confirm the peak positions and corresponding times of various trace or micro-amount components, and obtain the initial switching time of each valve;

[0032] The high-purity gas to be tested is introduced into the four-valve six-column system again, and the state of each valve is switched according to the initial switching time to obtain a second gas chromatogram;

[0033] According to the accurate gas chromatogram, the precise peak positions and corresponding times of various trace or micro-amount components can be confirmed, and the new switching time of each valve can be obtained;

[0034] Repeat the above operation, update the switching time and the gas chromatogram multiple times, until the final gas chromatogram is obtained, which can fully present the peaks of each impurity component;

[0035] Among them, when the high-purity gas to be tested is high-purity hydrogen, the impurities refer to O2 / Ar, N2, CO, CH4, CO2, C2H4, C2H6, and C2H2; when the high-purity gas to be tested is high-purity oxygen or high-purity argon, the impurities refer to H2, N2, CO, CH4, CO2, C2H4, C2H6, and C2H2; when the high-purity gas to be tested is high-purity nitrogen, the impurities refer to H2, O2 / Ar, CO, CH4, CO2, C2H4, C2H6, and C2H2.

[0036] According to the above technical solution, the confirmation process of the initial switching time is as follows:

[0037] When the high-purity gas to be tested enters the four-valve six-column valve system in the form of full injection,

[0038] The time sequence of the peaks on the first gas chromatogram is: H2, O2 / Ar (O2 and Ar appear as the same peak on the gas chromatogram), N2, CO, CH4, CO2, C2H4, C2H6, C2H2;

[0039] The starting time of a certain component peak is T1, and the end time is T2;

[0040] The starting time t1 and the ending time t2 of a component passing through the end of a separation column are:

[0041]

[0042] Wherein, l is the length that has passed through the pre-separation column and the main separation column;

[0043] L is the total length of the pre-separation column and the main separation column on the detection branch;

[0044] By default, the flow rate of the individual components through the pre-separation column and the main separation column is the same, and the time spent passing through the non-separation column area is negligible.

[0045] According to the above technical solution, when testing high-purity hydrogen,

[0046] In the first detection branch, a time point is selected according to the starting time t1 of H2 leaving the first pre-separation column and the starting time t1 of O2 / Ar leaving the first pre-separation column, and the ten-way valve B is switched; a first interval is selected according to the end time t2 of CH4 leaving the first pre-separation column and the starting time t1 of CO2 leaving the first pre-separation column, and the ten-way valve B is switched;

[0047] Switch the six-way valve a according to a second time point t2 when H2 leaves the first main separation column and a second time point t1 when O2 / Ar leaves the first main separation column;

[0048] In the second detection branch, a time point is selected according to the end time t2 of CH4 leaving the third pre-separation column and the start time t1 of CO2 leaving the third pre-separation column, and the six-way valve b is switched.

[0049] According to the above technical solution, when testing high-purity oxygen, nitrogen, or argon,

[0050] In the first detection branch, according to the starting time t1 when H2 leaves the second pre-separation column, a time point is selected before it, and the ten-way valve B is switched;

[0051] When analyzing high-purity nitrogen, the six-way valve a is switched at the starting time t1 of H2 and the ending time t2 of O2 / Ar, the starting time t1 and the ending time t2 of CO, and the starting time t1 and the ending time t2 of CH4;

[0052] When analyzing high-purity oxygen or high-purity argon, at the start time t1 and end time t2 of H2, the start time t1 and end time t2 of N2, the start time t1 and end time t2 of CO, and the start time t1 and end time t2 of CH4, the six-way valve a is switched;

[0053] In the second detection branch, a time point is selected according to the end time t2 of CH4 leaving the third pre-separation column and the start time t1 of CO2 leaving the third pre-separation column, and the six-way valve b is switched.

[0054] According to the above technical solution, the analysis method is carried out in a helium protection zone.

[0055] Principle of the present invention:

[0056] The first detection branch and the second detection branch are set in the same valve circuit system, and the trace impurities in the high-purity gas to be tested are divided into two categories by the first detection branch and the second detection branch, namely CO2, C2H4, C2H6, C2H2 and CH4, and mixed gas A. The two types of impurities will be further separated in the first detection branch and the second detection branch, and respectively transported to the PDHID detector for detection and analysis.

[0057] In the test gas intake assembly, a ten-way valve A is used to construct two gas intake branches for the gas to be tested. The ten-way valve A is switched to deliver a certain amount of the gas to be tested to the two detection branches, and the detection branches are purged by the carrier gas (helium is used as the carrier gas).

[0058] In the first detection branch, two parallel separation branches are formed by using a ten-way valve B. The first pre-separation column and the second pre-separation column are respectively arranged on the two separation branches, corresponding to the separation pretreatment of high-purity hydrogen and the separation treatment of high-purity argon, oxygen and nitrogen respectively; if high-purity hydrogen is tested, part of the high-purity hydrogen, CO2, C2H4, C2H6 and C2H2 are also discharged from the first detection branch. In the first detection branch, the high-purity gas in the pretreated gas is vented by switching the six-way valve a; if high-purity hydrogen is tested, the remaining main components are vented in the process; if high-purity oxygen, nitrogen and argon are tested, the high-purity gas and CO2, C2H4, C2H6 and C2H2 are vented in the process. Finally, the mixed gas A and CH4 are divided into multiple sections by the second main separation column and then transported to the PDHID detector in sequence.

[0059] In the second detection branch, the high-purity gas, mixed gas A, CH4, CO and CO2 in the high-purity gas to be detected are first slightly separated by the third pre-separation column, and then discharged by switching the six-way valve b. The remaining gas (CO2, C2H4, C2H6, C2H2) is again divided into multiple sections by the second main separation column and sequentially transported to the PDHID detector.

[0060] The present invention has the following beneficial effects:

[0061] 1. According to this method, the high-purity gas to be tested (hydrogen, oxygen, nitrogen, argon) is introduced into the first detection branch and the second detection branch respectively, and the first detection branch is used to detect the peak of the impurities with earlier peak time in the high-purity gas to be tested; the second detection branch is used to detect the peak of the impurities with later peak time in the high-purity gas. The detection results on the two detection branches are combined to obtain the final analysis result, so as to simplify the operation process and reduce the analysis cost, wherein the peak area reproducibility (n=6) is ≤1%, and the minimum detection limit of each impurity is less than 20ppb.

[0062] 2. The four-valve six-column system is used. Through the switching of four valves and the separation of six columns, the trace or trace impurities in a single type of high-purity gas are divided into two categories for separate detection. Secondly, through the switching of the valve state, the high-purity gas and the impurities not detected in this branch are discharged, and the impurities to be detected are transported to the pulse discharge helium ionization detector after repeated central cutting. Thus, the valve system is used to simultaneously detect trace or trace impurities in four high-purity gases, hydrogen, argon, oxygen, and nitrogen, to achieve the purpose of simplifying the operation process and reducing the analysis cost. The peak area reproducibility (n=6) is ≤1%, and the minimum detection limit of each impurity is less than 20ppb.

[0063] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The specific implementation of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The drawings described herein are used to provide further understanding of the present invention and constitute a part of this application. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0065] Figure 1 It is a schematic diagram of an embodiment of the present invention;

[0066] Figure 2 to Figure 5 The present invention provides a path diagram of an embodiment of detecting mixed gas A and CH4 using the first detection branch;

[0067] Figure 6-7 It is a path diagram of the embodiment provided by the present invention using the second detection branch to detect CO2, C2H2, C2H4, and C2H6;

[0068] Figure 8 This is a full-injection gas chromatogram when measuring high-purity nitrogen provided by the embodiment of the present invention;

[0069] Fig. 9 It is a gas chromatogram of analyzing high-purity hydrogen provided by the embodiment of the present invention;

[0070] Fig.10 It is a gas chromatogram of analyzing high-purity argon or oxygen provided by the embodiment of the present invention;

[0071] Fig.11 It is a gas chromatogram of analyzing high-purity nitrogen provided by the embodiment of the present invention;

[0072] In the figure, 1, PDHID detector; 2, ten-way valve A; 3, carrier gas inlet branch; 3-1, carrier gas pipeline; 3-2, pressure controller; 3-3, purifier; 4, quantitative loop; 5, test gas inlet branch; 5-1, inlet pipeline; 5-2, first pressure balance valve; 6, test gas outlet branch; 6-1, outlet pipeline; 6-2, second pressure balance valve; 7, first main separation column; 8, six-way valve a; 9, second main separation column; 10, ten-way valve B; 11, first pre-separation column; 12, second pre-separation column; 13, exhaust branch; 13-1, exhaust pipeline; 13-2, damping column; 14, third pre-separation column; 15, third main separation column; 16, six-way valve b; 17, protective atmosphere assembly. DETAILED DESCRIPTION

[0073] The following is combined with Figure 1-11 The principles and features of the present invention are described, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. In the following paragraphs, the present invention is described in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become clearer according to the following description and claims. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0074] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0075] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0076] Reference Figure 1 to Figure 7 As shown, the present invention provides a preferred valve circuit system suitable for the present method. The valve circuit system can also adopt other connection methods, such as adaptively swapping the pipeline structure.

[0077] The valve circuit system includes a PDHID detector 1; the valve circuit system is a four-valve six-column system.

[0078] Test gas inlet assembly, set the measuring loop, a sample inlet, a sample exhaust port, and two carrier gas outlets in the test system inlet assembly. The external gas source to be tested is stored in the quantitative loop, and the corresponding carrier gas outlet is selected according to the analysis requirements;

[0079] The first detection branch is connected between a carrier gas outlet of the test gas inlet assembly and the PDHID detector; the first detection branch is used to separate the mixed gas A and CH4 in the high-purity gas to be tested and transport them to the PDHID detector for detection;

[0080] The second detection branch is connected between another carrier gas outlet of the test gas inlet assembly and the PDHID detector; the second detection branch is used to separate CO2, C2H4, C2H6, and C2H2 in the high-purity gas to be tested and transport them to the PDHID detector for detection.

[0081] In this embodiment, a first detection branch and a second detection branch are set in the same valve circuit system, and the first detection branch and the second detection branch are used to divide the trace or trace impurities in the high-purity gas to be tested into two categories, namely CO2, C2H4, C2H6, C2H2 and mixed gas A, CH4. The two types of impurities will be further separated in the first detection branch and the second detection branch, and respectively transported to the PDHID detector for detection and analysis.

[0082] When the high-purity gas to be tested is high-purity hydrogen, the mixed gas A refers to a mixture of O2, N2 and CO, and the main component is hydrogen; when the high-purity gas to be tested is high-purity argon or high-purity oxygen, the mixed gas A refers to a mixture of H2, N2 and CO, and the main component is argon or oxygen respectively; when the high-purity gas to be tested is high-purity nitrogen, the mixed gas A refers to a mixture of O2, H2 and CO, and the main component is nitrogen.

[0083] The test gas inlet assembly includes a ten-way valve A (marked as 2 in the figure), two carrier gas inlet branches 3, two quantitative rings 4, and a test gas inlet branch 5 and a test gas outlet branch 6; the ten-way valve A is provided with ten connection points, which are marked as A1-A10 in clockwise direction;

[0084] The gas inlet branch to be tested is connected to A10, and the gas outlet branch to be tested is connected to A5; a quantitative loop is connected between A1 and A4, and between A6 and A9 through pipelines respectively; a carrier gas inlet branch is connected to A2 and A8 respectively; A3 is connected to the first detection branch as the carrier gas outlet, and A7 is connected to the second detection branch as another carrier gas outlet.

[0085] The gas intake branch to be tested includes an intake pipe 5-1 and a first pressure balance valve 5-2. The intake pipe is connected between A10 and an external gas source to be tested, and the first pressure balance valve is located on the intake pipe.

[0086] The outlet branch of the gas to be tested includes an outlet pipe 6-1 and a second pressure balance valve 6-2. The outlet pipe is connected between A5 and an external gas collection device to be tested, or between A5 and the atmosphere. The second pressure balance valve is located on the outlet pipe.

[0087] The first detection branch includes a pre-separation unit, a pipeline with a first main separation column 7, a main separation unit, and a pipeline with a second main separation column 9. The end of the pipeline with the second main separation column is connected to the PDHID detector. The first main separation column and the second main separation column separate the passing gas into multiple gas segments according to the components.

[0088] A ten-way valve B10, a first pre-separation column 11 and a second pre-separation column 12, a carrier gas inlet branch 3, an exhaust branch 13 and a carrier gas outlet connected to a pipeline provided with a first main separation column are provided in the pre-separation unit; according to the main components of the gas to be measured, the gas to be measured is passed into the first pre-separation column or the second pre-separation column, and the first pre-separation column or the second pre-separation column separates the gas to be measured into multiple gas segments according to the components; according to the required detection components of the gas to be measured, the gas segments containing the detection components in the multiple gas segments are transported to the carrier gas outlet of the pre-separation unit, and the remaining gas segments are transported to the exhaust branch;

[0089] The main separation unit is provided with a six-way valve a8, a carrier gas outlet connected to the pipeline provided with the second main separation column, an exhaust branch, and a carrier gas inlet branch. The six-way valve a transports the components to be detected in the gas segment transported by the first main separation column to the carrier gas outlet of the main separation unit, and the remaining gas segments are transported to the exhaust branch.

[0090] The second detection branch includes a pipeline provided with a third pre-separation column 14, a second separation unit, and a pipeline provided with a third main separation column 15 in sequence, and the end of the pipeline provided with the third main separation column is connected to the PDHID detector; the third pre-separation column and the third main separation column separate the passing gas into multiple gas segments according to the components;

[0091] The second separation unit is provided with a six-way valve b16, a carrier gas outlet connected to the pipeline provided with the third main separation column, an exhaust branch, and a carrier gas inlet branch. The six-way valve b transports the components to be detected in the gas segment transported by the first main separation column to the carrier gas outlet of the main separation unit, and the remaining gas segments are transported to the exhaust branch.

[0092] Among them, the first pre-separation column for analyzing impurities in high-purity hydrogen adopts a high specific surface area carbon molecular sieve column, and the specific surface area is not less than (1030 (m2 / g); the second pre-separation column, the first main separation column, and the second main separation column for analyzing high-purity oxygen, high-purity argon, and high-purity nitrogen all adopt 13X molecular sieve analysis columns; the analysis of impurities in high-purity helium can select one of the first pre-separation column and the second pre-separation column. The third pre-separation column and the third main separation column adopt a polymer porous microsphere analysis column (for example: Porapak Q). The outer diameter of the above 6 columns is preferably 2.1 mm, and the length is to be adjusted according to the method, which may be 1m, 2m, 3m. Other sizes can also be used.

[0093] Among them, the ten-way valve B is provided with ten connection points, which are marked as B1-B10 in clockwise direction; the carrier gas outlet of the test gas inlet assembly is connected to B10 (that is, B10 is connected to A10), the pipeline with the first main separation column is connected to B5; the first pre-separation column is connected between B1 and B6, and the second pre-separation column is connected between B4 and B9; the carrier gas inlet branch is connected to B2; B3 and B8 are directly connected by a pipeline; the exhaust branch is connected to B7;

[0094] The six-way valve a is provided with 6 connection points, which are marked as a1-a6 in clockwise direction; the pipeline of the first main separation column is connected to a6, the exhaust branch is connected to a1, the pipeline of the second main separation column is connected to a5, a2 and a4 are directly connected by pipelines, and the carrier gas inlet branch is connected to a3.

[0095] In addition to the above connection methods, the ten-way valve B and the six-way valve a may also be connected in other point-to-point ways, as long as the functions described in Example 1 are achieved.

[0096] Among them, the six-way valve b is provided with 6 connection points, which are marked as b1-b6 in clockwise direction; the pipeline of the first main separation column is connected to b6, the exhaust branch is connected to b1, the pipeline of the second main separation column is connected to b5, b2 and b4 are directly connected by pipelines, and the carrier gas inlet branch is connected to b3.

[0097] In addition to the above connection methods, the six-way valve b can also adopt other point connection methods, as long as the functions recorded in Example 1 are realized.

[0098] Among them, a plurality of exhaust branches and carrier gas inlet branches are arranged in the valve circuit system, the exhaust branch includes an exhaust pipeline 13-1 and a damping column 13-2 arranged on the exhaust pipeline, and the end of the exhaust pipeline is directly connected to the outside; the carrier gas inlet branch includes a carrier gas pipeline 3-1, a pressure controller 3-2 arranged in the carrier gas pipeline and a purifier 3-3, and the head end of the carrier gas pipeline is connected to the carrier gas source;

[0099] In order to avoid excessive pressure fluctuation in the valve when the six-way valve a switches the valve to a connected state, a carrier gas inlet branch is provided in the six-way valve a, and a damping column is also provided on the carrier gas inlet branch of the six-way valve a to balance the pressure.

[0100] The present invention provides an embodiment of analyzing high-purity hydrogen, nitrogen, oxygen, and argon based on the preferred valve circuit system, as follows:

[0101] In this embodiment, the outer diameters of the pre-separation column and the main separation column are both 3.2m, and the first pre-separation column is SC-ST, with a length of 2m; the second pre-separation column is MS-13X, with a length of 2m; the third pre-separation column is Shimadzu PN, with a length of 2m; the first main separation column is MS-13X, with a length of 2m; the second main separation column is MS-13X, with a length of 1m; and the third main separation column is PN, with a length of 1m.

[0102] The ten-way valve and the six-way valve used in the present invention both include two states, a single-line state and a double-line state; in the single-line state, the connection points 10 and 1, 2 and 3, 4 and 5, 6 and 7, 8 and 9 in the ten-way valve are connected, and the connection points 6 and 1, 2 and 3, 4 and 5 in the six-way valve are connected; in the double-line state, the connection points 1 and 2, 3 and 4, 5 and 6, 7 and 8, 9 and 10 in the ten-way valve are connected, and the connection points 1 and 2, 3 and 4, 5 and 6 in the six-way valve are connected. In the initial state, each ten-way valve and the six-way valve are in the single-line state.

[0103] The specific time of the following process is obtained by repeating the detection process 1-3 times after full sampling.

[0104] When testing high purity hydrogen:

[0105] Step 1: High-purity hydrogen is introduced into the ten-way valve through the gas inlet branch to be tested from the connection point 10. Since the ten-way valve A is in a single-line state, the gas to be tested fills the quantitative ring on the upper part of the ten-way valve A at this time, and the volume of the quantitative ring is 500μL; at the same time, each carrier gas inlet branch is always in an open state.

[0106] Step 2: Enable the first detection branch by switching the ten-way valve A from a single-line state to a double-line state (as the time zero point of the first detection branch). At this time, the gas to be tested fills the quantitative ring at the bottom of the ten-way valve A, and the volume of the quantitative ring is 500μL, preparing for the activation of the second detection branch.

[0107] In this process, the gas to be tested in the upper quantitative loop enters the connection node 10 of the ten-way valve B along with the carrier gas. Based on the valve circuit system of this embodiment, the ten-way valve B is initially in a single-line state, and the gas to be tested entering the ten-way valve B is directly passed into the first pre-separation column; and a large amount of high-purity hydrogen in the front section is discharged from the exhaust branch at the connection node 7 of the ten-way valve B.

[0108] Subsequently, the ten-way valve B is switched from a single-line state to a double-line state at 2.8±0.05 min, and a small amount of high-purity hydrogen, mixed gas A, and CH4 in the middle section are transported from the ten-way valve B connection node 5 to the first main separation column.

[0109] Finally, at 16±0.05min, the double-line state is switched to the single-line state, and the CO2, C2H2, C2H4, and C2H6 in the rear section are discharged from the exhaust branch at the ten-way valve B connecting node 7.

[0110] The six-way valve a switches from a single-line state to a double-line state at 2.8±0.05min. Before the switch, a small amount of high-purity hydrogen in the middle gas is discharged from the exhaust branch at the six-way valve a connection node 1. After the switch, the mixed gas A and CH4 in the middle gas are transported from the six-way valve a connection node 5 to the second main separation column, and finally sent to the PDHID detector for detection.

[0111] Step 3: Enable the second detection branch by switching the ten-way valve A from a two-line state to a single-line state (as the time zero point of the second detection branch).

[0112] In this process, the gas to be measured in the lower quantitative loop enters the third pre-separation column along with the carrier gas, and then enters the connection node 6 of the six-way valve b.

[0113] The six-way valve b switches from a single-line state to a double-line state at 18.1±0.05min. Before the switch, the high-purity hydrogen, mixed gas A, and CH4 in the gas to be tested are emptied from the exhaust branch at the six-way valve b connection node 1. After the switch, CO2, C2H2, C2H4, and C2H6 in the gas to be tested are transported from the six-way valve b connection node 5 to the third main separation column, and finally sent to the PDHID detector for detection. Fig. 9 shown.

[0114] Based on the final gas chromatographic Fig. 9 The corresponding test results obtained are as follows:

[0115]

[0116] When testing high purity nitrogen:

[0117] Step 1: High-purity nitrogen is introduced into the ten-way valve through the gas inlet branch to be tested from the connection point 10. Since the ten-way valve A is in a single-line state, the gas to be tested fills the quantitative ring on the upper part of the ten-way valve A at this time, and the volume of the quantitative ring is 500μL; at the same time, each carrier gas inlet branch is always in an open state.

[0118] Step 2: Enable the first detection branch by switching the ten-way valve A from a single-line state to a double-line state (as the time zero point of the first detection branch). At this time, the gas to be tested fills the quantitative ring at the bottom of the ten-way valve A, and the volume of the quantitative ring is 500μL, preparing for the activation of the second detection branch.

[0119] In this process, the gas to be tested in the upper quantitative loop enters the connection node 10 of the ten-way valve B along with the carrier gas. Based on the valve circuit system of this embodiment, the ten-way valve B is initially in a single-line state; when the ten-way valve A is switched from a single-line state to a double-line state, the ten-way valve B is switched from a single-line state to a double-line state; at this time, the gas to be tested entering the ten-way valve B is directly passed into the second pre-separation column.

[0120] Subsequently, the ten-way valve B is switched from the double-line state to the single-line state at 0.2 min, and the mixed gas A, high-purity nitrogen, and CH4 in the front section are transported from the ten-way valve B connection node 5 to the first main separation column.

[0121] The initial state of the six-way valve a is a single-line state, and it switches from the single-line state to the double-line state at 0.01 min. H2 and O2 are transported from the six-way valve a connecting node 5 to the second main separation column; it switches from the double-line state to the single-line state at 5±0.05 min, and part of the high-purity nitrogen is discharged from the exhaust branch at the six-way valve a connecting node 1.

[0122] At 8.8±0.05min, the single-line state is switched to the double-line state, and CH4 is transported from the six-way valve a connecting node 5 to the second main separation column; at 9.7±0.05min, the double-line state is switched to the single-line state, and part of the high-purity nitrogen is discharged from the exhaust branch at the six-way valve a connecting node 1.

[0123] At 12±0.05min, the single-line state is switched to the double-line state, and CO is transported from the six-way valve a connecting node 5 to the second main separation column; at 14.4±0.05min, the double-line state is switched to the single-line state, and the remaining high-purity nitrogen is discharged from the exhaust branch at the six-way valve a connecting node 1.

[0124] H2, O2, CH4, and CO entering the second main separation column are finally sent to the PDHID detector for detection.

[0125] Step 3: Enable the second detection branch by switching the ten-way valve A from a two-line state to a single-line state (as the time zero point of the second detection branch).

[0126] In this process, the gas to be measured in the lower quantitative loop enters the third pre-separation column along with the carrier gas, and then enters the connection node 6 of the six-way valve b.

[0127] The six-way valve b is switched from a single-line state to a double-line state at 18.1±0.05min. Before the switch, the high-purity hydrogen, mixed gas A, and CH4 in the gas to be tested are exhausted from the exhaust branch at the six-way valve b connection node 1. After the switch, CO2, C2H2, C2H4, and C2H6 in the gas to be tested are transported from the six-way valve b connection node 5 to the third main separation column, and finally sent to the PDHID detector for detection. As shown in 10.

[0128] Based on the final gas chromatographic Fig.10 The corresponding test results obtained are as follows:

[0129]

[0130]

[0131] When testing high purity argon or oxygen,

[0132] Step 1: High-purity argon or oxygen is introduced into the ten-way valve through the gas inlet branch to be tested from the connection point 10. Since the ten-way valve A is in a single-line state, the gas to be tested fills the quantitative ring on the upper part of the ten-way valve A at this time, and the volume of the quantitative ring is 500μL; at the same time, each carrier gas inlet branch is always in an open state.

[0133] Step 2: Enable the first detection branch by switching the ten-way valve A from a single-line state to a double-line state (as the time zero point of the first detection branch). At this time, the gas to be tested fills the quantitative ring at the bottom of the ten-way valve A, and the volume of the quantitative ring is 500μL, preparing for the activation of the second detection branch.

[0134] In this process, the gas to be tested in the upper quantitative loop enters the connection node 10 of the ten-way valve B along with the carrier gas. Based on the valve circuit system of this embodiment, the ten-way valve B is initially in a single-line state; when the ten-way valve A is switched from a single-line state to a double-line state, the ten-way valve B is switched from a single-line state to a double-line state; at this time, the gas to be tested entering the ten-way valve B is directly passed into the second pre-separation column.

[0135] Subsequently, the ten-way valve B is switched from the double-line state to the single-line state in 0.2 min, and the mixed gas A, high-purity argon or oxygen, and CH4 in the front section are transported from the ten-way valve B connection node 5 to the first main separation column.

[0136] The initial state of the six-way valve a is a single-line state, and it switches from the single-line state to the double-line state at 0.01 min, and H2 is transported from the six-way valve a connecting node 5 to the second main separation column; it switches from the double-line state to the single-line state at 2.5±0.05 min, and part of the high-purity argon or oxygen is discharged from the exhaust branch at the six-way valve a connecting node 1.

[0137] At 4.5±0.05min, the single-line state is switched to the double-line state, and N2 is transported from the six-way valve a connecting node 5 to the second main separation column; at 6.1±0.05min, the double-line state is switched to the single-line state, and part of the high-purity argon or oxygen is discharged from the exhaust branch at the six-way valve a connecting node 1.

[0138] At 8.5±0.05min, the single-line state is switched to the double-line state, and CH4 is transported from the six-way valve a connecting node 5 to the second main separation column; at 9.8±0.05min, the double-line state is switched to the single-line state, and part of the high-purity nitrogen is discharged from the exhaust branch at the six-way valve a connecting node 1.

[0139] At 12±0.05min, the single-line state is switched to the double-line state, and CO is transported from the six-way valve a connecting node 5 to the second main separation column; at 14.4±0.05min, the double-line state is switched to the single-line state, and the remaining high-purity argon or oxygen is discharged from the exhaust branch at the six-way valve a connecting node 1.

[0140] H2, N2, CH4, and CO entering the second main separation column are finally sent to the PDHID detector for detection.

[0141] Step 3: Enable the second detection branch by switching the ten-way valve A from a two-line state to a single-line state (as the time zero point of the second detection branch).

[0142] In this process, the gas to be measured in the lower quantitative loop enters the third pre-separation column along with the carrier gas, and then enters the connection node 6 of the six-way valve b.

[0143] The six-way valve b switches from a single-line state to a double-line state at 18.1min±0.05min. Before the switch, the high-purity hydrogen, mixed gas A, and CH4 in the gas to be tested are emptied from the exhaust branch at the six-way valve b connection node 1. After the switch, CO2, C2H2, C2H4, and C2H6 in the gas to be tested are transported from the six-way valve b connection node 5 to the third main separation column, and finally sent to the PDHID detector for detection. Fig.11 shown.

[0144] Based on the final gas chromatographic Fig.11 The corresponding test results obtained are as follows:

[0145]

[0146] The high-purity gases that can be analyzed using the present invention are shown in the following table:

[0147]

[0148] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A method for analyzing trace or micro-amount impurities in a variety of high-purity gases, characterized in that: Confirm that the high-purity gas to be tested is one of high-purity hydrogen, high-purity oxygen, high-purity nitrogen, and high-purity argon; The high-purity gas to be tested is introduced, and the set volume of the high-purity gas to be tested is respectively charged into the two detection branches through the switching of the ten-way valve; Through the separation of the pre-separation column and the main separation column in the first detection branch, and the switching of the ten-way valve and the six-way valve, the main components, CO2, C2H2, C2H4, and C2H6 in the high-purity gas to be tested are emptied, and the remaining mixed gas A and CH4 are separated and transported to the PDHID detector for detection; After separation of the pre-separation column and the main separation column in the second detection branch and switching of the six-way valve, the main component, mixed gas A, and CH4 in the high-purity gas to be tested are emptied, and the remaining CO2, C2H2, C2H4, and C2H6 are separated and transported to the PDHID detector for detection; Among them, when the high-purity gas to be tested is high-purity hydrogen, the mixed gas A refers to a mixture of O2, N2 and CO, and the main component refers to hydrogen; when the high-purity gas to be tested is high-purity argon or high-purity oxygen, the mixed gas A refers to a mixture of H2, N2 and CO, and the main component refers to argon or oxygen respectively; when the high-purity gas to be tested is high-purity nitrogen, the mixed gas A refers to a mixture of O2, H2 and CO, and the main component refers to nitrogen.

2. The method for analyzing micro or trace impurities in a plurality of high purity gases according to claim 1, characterized in that: The method adopts a four-valve six-column valve circuit system, including a test gas intake assembly, a first detection branch, and a second detection branch; The test gas inlet assembly includes a ten-way valve A, and the high-purity gas to be tested enters the ten-way valve A. By switching the state of the ten-way valve A, the high-purity gas to be tested is sequentially sent to the first detection branch and the second detection branch through the switching of the state of the ten-way valve A; The first detection branch includes a ten-way valve B, a first pre-separation column and a second pre-separation column arranged on the ten-way valve B, a six-way valve a, a first main separation column arranged between the ten-way valve B and the six-way valve a, and a second main separation column arranged between the six-way valve a and the PDHID detector; according to the type of the high-purity gas to be detected, the state of the ten-way valve B is switched to control the high-purity gas A to be detected to pass into the first pre-separation column or the second pre-separation column; When the high-purity gas to be measured is high-purity hydrogen, part of the main components, CO2, C2H2, C2H4, and C2H6 are emptied by switching the state of the ten-way valve B, and the remaining main components and the mixed gas A are introduced into the second main separation column; and the remaining main components are emptied by switching the six-way valve a once; When the high-purity gas to be measured is high-purity oxygen, high-purity nitrogen or high-purity argon, the high-purity gas to be measured is introduced into the second main separation column by switching the state of the ten-way valve B; and the main component, CO2, C2H2, C2H4, and C2H6 are emptied by switching the six-way valve a multiple times; The second detection branch includes a six-way valve b, a third pre-separation column arranged in front of the six-way valve b, and a third main separation column arranged at the rear of the six-way valve; by switching the six-way valve b, the main component, the mixed gas A, and CH4 are emptied, and CO2, C2H2, C2H4, and C2H6 are transported to the third main separation column; All pre-separation columns and main separation columns are used to separate the incoming gas and output it in different time periods according to its components.

3. The method for analyzing micro or trace impurities in a plurality of high purity gases according to claim 2, characterized in that: The first pre-separation column uses a high specific surface area carbon molecular sieve column; the second pre-separation column, the first main separation column, and the second main separation column all use carbon molecular sieve analysis columns; the third pre-separation column and the third main separation column use polymer porous microsphere analysis columns.

4. The method for analyzing micro or trace impurities in a plurality of high purity gases according to claim 2, characterized in that: When the high-purity gas to be measured is high-purity hydrogen, In the first detection branch, the ten-way valve A is switched to deliver a quantitative amount of high-purity gas to be detected to the first pre-separation column; Part of the main components and CO2, C2H2, C2H4, and C2H6 are emptied by switching the ten-way valve B, and then the remaining main components are emptied by switching the six-way valve a; In the second detection branch, the ten-way valve A is switched to deliver a quantitative amount of high-purity gas to be detected to the second pre-separation column; The main component, mixed gas A, and CH4 are exhausted by switching the six-way valve.

5. The method for analyzing micro or trace impurities in a plurality of high purity gases according to claim 2, characterized in that: When the high-purity gas to be measured is high-purity oxygen, high-purity nitrogen or high-purity argon; In the first detection branch, the ten-way valve A is switched to deliver a quantitative amount of high-purity gas to be tested to the first pre-separation column; The high-purity gas to be tested is delivered to the first main separation column by switching the ten-way valve B, and CO2, C2H2, C2H4, C2H6 and the main component are evacuated by multiple switching of the six-way valve a; In the second detection branch, the ten-way valve A is switched to deliver a quantitative amount of high-purity gas to be tested to the second pre-separation column; The main component, mixed gas A, and CH4 are exhausted by switching the six-way valve.

6. The method for analyzing trace or micro-amount impurities in a plurality of high-purity gases according to any one of claims 4-5, characterized in that: The switching time for each valve is determined as follows: The high-purity gas to be tested is introduced into the valve path system of four valves and six columns by full injection to obtain a first gas chromatogram; According to the first gas chromatogram, confirm the peak positions and corresponding times of various trace or micro-amount components, and obtain the initial switching time of each valve; The high-purity gas to be tested is introduced into the four-valve six-column system again, and the state of each valve is switched according to the initial switching time to obtain a second gas chromatogram; According to the accurate gas chromatogram, the precise peak positions and corresponding times of various trace or micro-amount components can be confirmed, and the new switching time of each valve can be obtained; Repeat the above operation, update the switching time and the gas chromatogram multiple times, until the final gas chromatogram is obtained, which can fully present the peaks of each impurity component; Among them, when the high-purity gas to be tested is high-purity hydrogen, the impurities refer to O2 / Ar, N2, CO, CH4, CO2, C2H4, C2H6, and C2H2; when the high-purity gas to be tested is high-purity oxygen or high-purity argon, the impurities refer to H2, N2, CO, CH4, CO2, C2H4, C2H6, and C2H2; when the high-purity gas to be tested is high-purity nitrogen, the impurities refer to H2, O2 / Ar, CO, CH4, CO2, C2H4, C2H6, and C2H2.

7. The method for analyzing micro or trace impurities in a plurality of high purity gases according to claim 6, characterized in that: The confirmation process of the initial switching time is as follows: When the high-purity gas to be tested enters the four-valve six-column valve system in the form of full injection, The time sequence of the peaks on the first gas chromatogram is: H2, O2 / Ar, N2, CO, CH4, CO2, C2H4, C2H6, C2H2; The starting time of a certain component peak is T1, and the end time is T2; The starting time t1 and the ending time t2 of a component passing through the end of a separation column are: Wherein, L is the length that has passed through the pre-separation column and the main separation column; L is the total length of the pre-separation column and the main separation column on the detection branch; By default, the flow rate of the individual components through the pre-separation column and the main separation column is the same, and the time spent passing through the non-separation column area is negligible.

8. The method for analyzing micro or trace impurities in a plurality of high purity gases according to claim 7, characterized in that: When the high-purity gas to be measured is high-purity hydrogen, In the first detection branch, a time point is selected according to the starting time t1 of H2 leaving the first pre-separation column and the starting time t1 of O2 / Ar leaving the first pre-separation column, and the ten-way valve B is switched; a first interval is selected according to the end time t2 of CH4 leaving the first pre-separation column and the starting time t1 of CO2 leaving the first pre-separation column, and the ten-way valve B is switched; Switch the six-way valve a according to a second time point t2 when H2 leaves the first main separation column and a second time point t1 when O2 / Ar leaves the first main separation column; In the second detection branch, a time point is selected according to the end time t2 of CH4 leaving the third pre-separation column and the start time t1 of CO2 leaving the third pre-separation column, and the six-way valve b is switched.

9. The method for analyzing micro or trace impurities in a plurality of high purity gases according to claim 7, characterized in that: When the high purity gas to be measured is high purity oxygen, high purity nitrogen or high purity argon, In the first detection branch, according to the starting time t1 when H2 leaves the second pre-separation column, a time point is selected before it, and the ten-way valve B is switched; When analyzing high-purity nitrogen, the six-way valve a is switched at the starting time t1 of H2 and the ending time t2 of O2 / Ar, the starting time t1 and the ending time t2 of CO, and the starting time t1 and the ending time t2 of CH4; When analyzing high-purity oxygen or high-purity argon, at the start time t1 and end time t2 of H2, the start time t1 and end time t2 of N2, the start time t1 and end time t2 of CO, and the start time t1 and end time t2 of CH4, the six-way valve a is switched; In the second detection branch, a time point is selected according to the end time t2 of CH4 leaving the third pre-separation column and the start time t1 of CO2 leaving the third pre-separation column, and the six-way valve b is switched.

10. The method for analyzing micro or trace impurities in a plurality of high purity gases according to claim 1, characterized in that: The analytical method was carried out under helium protection.

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