Sampling device, analysis system and method for trace sulfur in high-sulfur-content gas

Abstract

The invention discloses a sampling device, an analysis system and a method for trace sulfur in high-sulfur-content gas, the sampling device comprises a sampling barrel and an upper cover covering the opening part of the sampling barrel, and the sampling barrel and the upper cover are in sealed connection; the upper cover is provided with a sample gas inlet pipe, a sample gas outlet pipe, a vacuum gas inlet pipe and a pressure gas inlet pipe which are communicated with the inside of the sampling barrel, and the sample gas inlet pipe, the sample gas outlet pipe, the vacuum gas inlet pipe and the pressure gas inlet pipe are respectively provided with a valve I, a valve II, a valve III and a valve IV; a sampling bag is arranged in the sampling barrel, a valve V and a valve VI are respectively mounted on the sampling bag, the valve V is connected with the sample gas outlet pipe through a pipeline joint I, and the valve VI is connected with the sample gas inlet pipe through a pipeline joint II. According to the invention, representative sampling of a negative pressure sample can be realized, effective separation of high-content hydrogen sulfide and other trace sulfur-containing components can be realized, the high-content hydrogen sulfide is prevented from entering a detector, and the detection accuracy of sulfur-containing compounds in the sample can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas chromatography analysis, and in particular to a sampling device, an analysis system and a method for sampling trace sulfur in high-sulfur gas. Background Art

[0002] High-sulfur gas reservoirs refer to gas reservoirs where the produced natural gas contains 30 to 150 g / m³ of hydrogen sulfide. In addition to hydrogen sulfide, these reservoirs also contain trace amounts of sulfur compounds such as sulfur oxides, carbon monoxide, and mercaptans. Because sulfur compounds pose a serious threat to human health, safety, and the environment, and can even be life-threatening, existing technologies typically require the determination of the sulfur compound content in produced gas. However, during the production of sour natural gas and similar gases, some samples have very low pressures, even below atmospheric pressure. Samples such as flash steam from gas field water, desulfurized gas from natural gas processing plants, process gas, and tail gas may all have pressures below atmospheric pressure. However, in actual production, these samples require sampling and analysis. Conventional pressure sampling methods cannot obtain representative samples, and thus, inaccurate results. At the same time, since the high content of hydrogen sulfide in the sample will interfere with other trace sulfur components (such as sulfur oxides, carbon monoxide, methyl mercaptan, etc.) during the analysis process, it is impossible to perform accurate qualitative and quantitative analysis of other trace sulfur components. This will cause difficulties in the safe and green development of high-sulfur gas fields without basic data. Therefore, there is an urgent need to develop sampling, analysis and detection technologies suitable for such samples. Summary of the Invention

[0003] The purpose of the present invention is to address the problems in the prior art of analyzing the trace sulfur content in high-sulfur gas, namely, that a representative sample cannot be obtained using a conventional pressure sampling method and that the analysis of the trace sulfur is interfered with. The present invention provides a sampling device, an analysis system and a method for trace sulfur in high-sulfur gas. The method can not only achieve representative sampling of negative pressure samples, but also effectively separate high-content hydrogen sulfide from trace amounts of other sulfur-containing components, thereby preventing high-content hydrogen sulfide from entering the detector and improving the detection accuracy of sulfur-containing compounds in the sample.

[0004] The present invention is achieved through the following technical solutions:

[0005] In the first aspect, the present invention provides a sampling device for trace sulfur in high-sulfur gas, comprising a sampling barrel and an upper cover covering the mouth of the sampling barrel, wherein a sealed connection is formed between the sampling barrel and the upper cover; the upper cover is equipped with a sample air inlet pipe, a sample air outlet pipe, a vacuum air inlet pipe and a pressure air inlet pipe connected to the interior of the sampling barrel, and valve one, valve two, valve three and valve four are respectively installed on the sample air inlet pipe, the sample air outlet pipe, the vacuum air inlet pipe and the pressure air inlet pipe; a sampling bag is provided in the sampling barrel, and valve five and valve six are respectively installed on the sampling bag, wherein valve five is connected to the sample air outlet pipe through pipeline connector one, and valve six is ​​connected to the sample air inlet pipe through pipeline connector two.

[0006] In some embodiments, the sampling bag is a double-valve sulfur-resistant sampling bag.

[0007] In a second aspect, the present invention provides a method for sampling trace sulfur in high-sulfur gas using the sampling device for sampling trace sulfur in the first aspect, comprising the following steps:

[0008] Step 1: Open the upper cover and connect the sampling bag to the sample inlet pipe and the sample outlet pipe. After the sampling bag is connected, open valves 5 and 6 on the sampling bag;

[0009] Step 2: Put the upper cover on the mouth of the sampling barrel and make the upper cover and the sampling barrel sealed;

[0010] Step 3: Connect the sampling line to the sample port at valve 1 on the upper cover, and connect the vent line to the alkali solution barrel or dedicated venting system at valve 2;

[0011] Step 4: Use a vacuum tube to connect the vacuum inlet of the upper cover to the vacuum pump, and connect the positive pressure gas pump to the gas inlet;

[0012] Step 5: Before use, all valves on the upper cover are in the closed state;

[0013] Step 6. Open valve 3 and start the vacuum pump. When the pressure in the sampling barrel drops to the required level, close valve 3 and the vacuum pump and check if the sampling barrel is leaking. If so, find the cause and continue until there is no leakage.

[0014] Step 7. Open valve 3, start the vacuum pump to evacuate the sampling barrel, then slowly open valve 1 to allow the sample gas to enter the sampling bag under negative pressure. After the sampling bag is completely inflated, close valve 1, open valve 2, open valve 4, start the positive pressure gas pump to slowly inflate the sampling barrel, observe the pressure gauge indication and the amount of gas in the sampling bag, and after the gas in the sampling bag is completely discharged, quickly close valve 2, the positive pressure gas pump, and valve 4 in sequence.

[0015] Step 8. Repeat step 7 at least 5 times;

[0016] Step 9. After sampling is completed, close valve 1 and valve 2; remove the connecting pipelines at the gas inlet and the vacuum inlet, open valve 4, let air enter the sampling barrel until the pressure is balanced with the atmosphere, remove the upper cover, close valve 5 and valve 6 of the sampling bag, separate the sampling bag from pipeline connector 1 and pipeline connector 2, and the sampling is completed in one step.

[0017] In a third aspect, the present invention provides an analysis system for trace sulfur in high-sulfur gas, comprising a gas chromatograph and the sampling device for trace sulfur in high-sulfur gas according to the first aspect.

[0018] In some embodiments, the gas chromatograph includes an injection system, a chromatographic column, a heart-cutting assembly and a detector. The injection system includes a selection valve, a quantitative tube and a carrier gas tube, and the selection valves are connected by a sample gas tube; in the injection system, both ends of the quantitative tube are connected to the selection valve, the carrier gas tube is connected to the selection valve, the selection valve is connected to the chromatographic column, the outlet of the chromatographic column is connected to the heart-cutting assembly, and the outlet of the heart-cutting assembly is connected to the detector.

[0019] In some embodiments, the selection valve has a first state and a second state. When the selection valve is switched to the first state, the gas in the sample gas tube can pass through the quantitative tube and directly discharge from the analysis system. When the selection valve is switched to the second state, the gas in the carrier gas tube can flow to the chromatographic column through the quantitative tube.

[0020] In some embodiments, the chromatography column and the heart-cutting assembly are disposed in a column box, and the column box is connected to a refrigerant via a control valve.

[0021] In some embodiments, the detector is a SCD detector.

[0022] In some embodiments, the chromatography column is a capillary column.

[0023] In a fourth aspect, the present invention provides an analysis method for trace sulfur in high-sulfur gas using the analysis system of the third aspect, comprising the following steps:

[0024] Step 1: sampling gas through a sampling device;

[0025] Step 2: After sampling is completed, connect the sampling bag to the sample input end of the selection valve, switch the selection valve to the first state, and the gas in the sample gas pipe can pass through the quantitative tube and directly discharge the analysis system to complete the sample gas sampling;

[0026] Step 3: Switch the selection valve to the second state, bring out the sample gas in the quantitative tube through the carrier gas, and bring the sample gas of the set flow rate into the chromatographic column through the flow controller, and then enter the heart cutting component. By changing the gas flow direction, the high content of hydrogen sulfide in the sample is removed, and other trace components are introduced into the detector.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] The present invention can achieve representative sampling of negative pressure samples by using a special negative pressure sampling device; through low-temperature sampling, it can achieve effective separation of high-content hydrogen sulfide and trace amounts of other sulfur-containing components; through the use of a heart cutting component and low-temperature sampling (that is, column box temperature), it can achieve effective removal of extremely high-content hydrogen sulfide in the sample, avoiding the contamination of the SCD detector caused by high-content hydrogen sulfide entering the detector, and can also achieve effective separation of nearly 20 sulfur-containing compounds in the sample, thereby realizing accurate qualitative and quantitative detection of nearly 20 trace sulfur-containing compound components. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings:

[0030] Figure 1 Schematic diagram of a sampling device for trace sulfur in high-sulfur gas according to the present invention;

[0031] Figure 2 This is a schematic plan view of the upper cover of the sampling device of the present invention;

[0032] Figure 3 Schematic diagram of a gas chromatograph in the analysis system for trace sulfur in high-sulfur gas of the present invention (injection state);

[0033] Figure 4 Schematic diagram of a gas chromatograph (detection state) in the analysis system for trace sulfur in high-sulfur gas according to the present invention.

[0034] Markings and corresponding parts names in the accompanying drawings:

[0035] 1-Valve 1; 2-Valve 2; 3-Valve 3; 4-Valve 4; 5-Upper cover; 51-Sample inlet pipe; 52-Sample outlet pipe; 53-Vacuum inlet pipe; 54-Pressure gas inlet pipe; 6-Sampling barrel; 7-Valve 5; 8-Valve 6; 9-Sampling bag; 10-Selection valve; 11-Chromatographic column; 12-Heart cutting assembly; 13-Detector; 14-Quantitative tube. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0038] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0039] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0040] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0041] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0042] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces), unless otherwise clearly and specifically defined.

[0043] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0044] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0045] Please refer to Figure 1 and Figure 2 , a sampling device for trace sulfur in high-sulfur gas provided in an embodiment of the present application includes a sampling barrel 6 and an upper cover 5 covering the mouth of the sampling barrel 6, and a sealed connection is formed between the sampling barrel 6 and the upper cover 5; the upper cover 5 is equipped with a sample air inlet pipe 51, a sample air outlet pipe 52, a vacuum air inlet pipe 53 and a pressure air inlet pipe 54 connected to the interior of the sampling barrel 6, and valve one 1, valve two 2, valve three 3 and valve four 4 are respectively installed on the sample air inlet pipe 51, the sample air outlet pipe 52, the vacuum air inlet pipe 53 and the pressure air inlet pipe 54; a sampling bag 9 is provided in the sampling barrel 6, and valve five 7 and valve six 8 are respectively installed on the sampling bag 9, wherein valve five 7 is connected to the sample air outlet pipe 52 through a pipeline connector one (not shown in the figure), and valve six 8 is connected to the sample air inlet pipe 51 through a pipeline connector two (not shown in the figure).

[0046] According to some embodiments of the present application, the sampling bag 9 is a double-valve sulfur-resistant sampling bag. Specifically, the sampling bag 9 is made of sulfur-corrosion-resistant material and has two interfaces for respectively setting valve 5 7 and valve 6 8 .

[0047] According to some embodiments of the present application, in order to facilitate observation of the filling state of the sampling bag during the sampling process, the sampling barrel 6 and / or the upper cover 5 can be made of a transparent material, or a transparent observation window can be designed on the sampling barrel 6 and / or the upper cover 5.

[0048] A sampling method for trace sulfur in high-sulfur gas using the above-mentioned sampling device provided in the embodiments of the present application includes the following steps:

[0049] Step 1: Open the upper cover 5 of the sampling device, and tightly connect the double-valve sulfur-resistant sampling bag 9 at the pipeline joint 1 and pipeline joint 2 respectively. After the connection is completed, open the valve 5 7 and valve 6 8 on the sampling bag 9;

[0050] Step 2: Place the upper cover 5 of the sampling device on the sampling barrel 6 stably, and make sure that the sampling barrel 6 and the upper cover 5 are tightly sealed and leak-proof under negative pressure conditions;

[0051] Step 3: Connect the polytetrafluoroethylene sample gas line to the sample gas sampling port at valve 1 on the upper cover 5 of the sampling device, and connect the vent line to the alkali liquid barrel or the on-site dedicated venting system at valve 2;

[0052] Step 4: Use a vacuum tube to connect the vacuum inlet of the upper cover 5 of the sampling device to the vacuum pump, and connect the gas inlet to a slightly positive pressure gas pump;

[0053] Step 5: Before using the sampling device, all valves of the upper cover 5 (i.e., valve 1, valve 2, valve 3, and valve 4) are in the closed state;

[0054] Step 6. Open valve 3 and start the vacuum pump. The vacuum pressure gauge shows that the pressure in the sampling barrel 6 gradually decreases. When the pressure in the sampling barrel 6 is lower than -0.05MPa, close valve 3 and the vacuum pump and observe whether the pressure on the vacuum pressure gauge changes. If the pressure gradually increases, the sampling device is leaking. Find the cause until the leak stops.

[0055] Step 7: Open valve 3 3, start the vacuum pump, and slowly open valve 1 1 to allow the sample gas to enter the sampling bag 9 under negative pressure. After the sampling bag 9 is completely inflated, close valve 1 1, open valve 2 2, open valve 4 4, and start the micro-positive pressure gas pump to slowly inflate the sampling barrel 6. Observe the pressure gauge indication and the amount of gas in the sampling bag 9 in the sampling barrel 6. After the gas in the sampling bag 9 is completely discharged, quickly close valve 2 2, the micro-positive pressure gas pump, and valve 4 4 ​​in sequence.

[0056] Step 8. Repeat step 7 at least 5 times;

[0057] Step 9. After sampling is completed, close valve 1 and valve 2; remove the connecting pipelines at the gas inlet and the vacuum inlet, open valve 4, let air enter the sampling barrel 6 until the pressure is balanced with the atmosphere, remove the upper cover 5, close valve 5 7 and valve 6 8 of the sampling bag 9, separate pipeline connector 1 and pipeline connector 2 from the sampling bag 9, and one-time sampling is completed.

[0058] Please refer to Figure 3 and Figure 4 ,in Figure 3 This is a schematic diagram of the gas chromatograph injection state in the analysis system. Figure 4 The present invention provides a system for analyzing trace sulfur in high-sulfur gas, which includes a gas chromatograph and the above-mentioned sampling device for sampling trace sulfur in high-sulfur gas.

[0059] According to some embodiments of the present application, the gas chromatograph includes an injection system, a gas path control system, a chromatographic column 11, a center cutting assembly 12 and a detector 13; the injection system includes a selection valve 10, a quantitative tube 14 and a carrier gas tube, the selection valve 10 is connected to the sample gas tube, both ends of the quantitative tube 14 are connected to the selection valve 10, the carrier gas tube is connected to the selection valve 10, the selection valve 10 is connected to the chromatographic column 11, the outlet of the chromatographic column 11 is connected to the center cutting assembly 12, and the outlet of the center cutting assembly 12 is connected to the detector 13; the gas path control system mainly includes a gas source, a purification drying tube and a flow controller, and is a closed pipeline system for continuous operation of the carrier gas, and a pure carrier gas with a stable flow rate is obtained through the gas path control system.

[0060] According to some embodiments of the present application, the selector valve 10 has a switchable first state and a second state. When the selector valve 10 is switched to the first state, the gas in the sample gas line can pass through the quantitative tube 14 and directly discharge from the analysis system. When the selector valve 10 is switched to the second state, the gas in the carrier gas line can flow through the quantitative tube 14 to the chromatographic column 11. The selector valve 10 is a six-way gas plane valve having a carrier gas inlet, a carrier gas outlet, and a sample inlet and a sample outlet.

[0061] According to some embodiments of the present application, the chromatographic column 11 and the center-cutting component 12 are arranged in a column box (not shown in the figure), and the column box is connected to the refrigerant through a control valve to lower the column box temperature and realize low-temperature injection. Among them, the column box and the refrigerant pipeline are not shown in the figure. The refrigerant can be dry ice or liquid nitrogen. By setting the refrigerant, the column box temperature can be controlled as low as -50°C, and the temperature control accuracy is ±0.1°C. Through low-temperature injection, high-content hydrogen sulfide and other trace sulfur-containing components can be effectively separated. By using the center-cutting component and low-temperature injection (that is, the column box temperature), the effective removal of extremely high-content hydrogen sulfide in the sample can be achieved.

[0062] According to some embodiments of the present application, the detector 13 is an SCD detector. An SCD detector is a sulfur chemiluminescence detector, currently recognized as the most sensitive and selective detector for detecting sulfur. Its detection principle is as follows: Sulfur-containing compounds eluted from the chromatographic column enter the combustion chamber along with the carrier gas, burn at high temperatures (>1800°C) to form SO, which then reacts with ozone (O3) to form excited SO2, which decays to the ground state and emits a characteristic blue spectrum (280-420nm). The light wave hv passes through a filter and is received by a photomultiplier tube for detection, thereby achieving sulfur detection.

[0063] According to some embodiments of the present application, the chromatographic column 11 is a capillary column. A capillary column, also known as a microcolumn, has an inner diameter of 0.2-0.5 mm. The specific structure and principle of the chromatographic column are not described here in detail.

[0064] An analysis method for trace sulfur in high-sulfur gas using the above-mentioned analysis system is provided in an embodiment of the present application, comprising the following steps:

[0065] Step 1: Sampling process: Use the sampling device to sample the sample gas from the sampling bag 9 according to the above sampling method.

[0066] Step 2: Sampling process: Connect one of the valves (valve 5 7 or valve 6 8) on the sampling bag 9 to the sample input end of the selection valve 10, switch the selection valve 10 to the first state, and the gas in the sample gas pipe can pass through the quantitative tube 14 and directly discharge the analysis system to complete the sample gas sampling. Figure 3 During the sampling process, the sampling bag 9 can be squeezed manually to allow the sample gas in the sampling bag 9 to slowly enter the quantitative tube 14. Alternatively, the sampling bag 9 can be placed in a sampling device, and then pressurized gas is input into the sampling device. When the pressure of the gas in the device is greater than the pressure in the sampling bag 9, the sample gas in the sampling bag 9 will be slowly squeezed out and enter the quantitative tube 14.

[0067] Step 3: Analysis process: The gas chromatograph is equipped with a dedicated control valve to connect the refrigerant (dry ice or liquid nitrogen) to control the column box temperature as low as -50°C, with a temperature control accuracy of ±0.1°C (not shown in the figure). Figure 4 As shown, the selection valve 10 is switched to the second state, and the carrier gas N2 (usually an inert gas, such as nitrogen, helium, or argon, etc.) is allowed to carry out the sample gas in the quantitative tube 14, and the sample gas with a set flow rate is brought into the chromatographic column 11 through the flow controller CAP, and enters the center cutting component 12. The center cutting component 12 completely separates the high-content hydrogen sulfide from the adjacent sulfur, oxygen, and carbon at low temperature, and then cuts off the high-content hydrogen sulfide by changing the gas flow direction, so that the hydrogen sulfide does not enter the trace sulfur detector 13, thereby effectively avoiding the contamination of the detector by high sulfur content.

[0068] According to some embodiments of the present application, the analysis system has a total of three columns. The first chromatographic column 11 is mainly used for the analysis of various sulfur-containing compounds (i.e., the analytical column). There are two empty columns and one connecting column. Figure 3 R and SCD detector 13, used to sequentially introduce the components separated by the chromatographic column 11 into the SCD detector 13, one connected to Figure 3 The S position is used for pressure balance and to vent the removed hydrogen sulfide. Heart-cutting assembly 12 switches valve 2 (Valve 2 in the figure) over a certain period of time to allow high levels of hydrogen sulfide in the sample to vent through valve 2, effectively preventing high levels of hydrogen sulfide from entering SCD detector 13 and contaminating the detector. After the hydrogen sulfide is removed and vented, valve 2 is switched to allow trace components in the sample other than hydrogen sulfide to be introduced into SCD detector 13, enabling qualitative and quantitative analysis of these components.

[0069] The analysis conditions are:

[0070]

[0071]

[0072] The present invention can achieve representative sampling of negative pressure samples by using a special negative pressure sampling device; through low-temperature sampling, it can achieve effective separation of high-content hydrogen sulfide and trace amounts of other sulfur-containing components; through the use of a heart cutting component and low-temperature sampling (that is, column box temperature), it can achieve effective removal of extremely high-content hydrogen sulfide in the sample, avoiding the contamination of the SCD detector caused by high-content hydrogen sulfide entering the detector, and can also achieve effective separation of nearly 20 sulfur-containing compounds in the sample, thereby realizing accurate qualitative and quantitative detection of nearly 20 trace sulfur-containing compound components.

[0073] It should be noted that the parts not described in detail in the embodiments of the present application belong to the common knowledge in the art.

[0074] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sampling device for trace sulfur in high-sulfur gas, characterized in that: It includes a sampling barrel and an upper cover that covers the mouth of the sampling barrel, and a sealed connection is formed between the sampling barrel and the upper cover; the upper cover is equipped with a sample air inlet pipe, a sample air outlet pipe, a vacuum air inlet pipe and a pressure air inlet pipe that are connected to the inside of the sampling barrel, and valve one, valve two, valve three and valve four are respectively installed on the sample air inlet pipe, sample air outlet pipe, vacuum air inlet pipe and pressure air inlet pipe; a sampling bag is provided in the sampling barrel, and valve five and valve six are respectively installed on the sampling bag, wherein valve five is connected to the sample air outlet pipe through pipeline connector one, and valve six is ​​connected to the sample air inlet pipe through pipeline connector two.

2. The sampling device for trace sulfur in high-sulfur gas according to claim 1, characterized in that: The sampling bag is a double-valve sulfur-resistant sampling bag.

3. A sampling method using the sampling device for trace sulfur in high-sulfur gas according to claim 1, characterized in that: The following steps are involved: Step 1: Open the upper cover and connect the sampling bag to the sample inlet pipe and the sample outlet pipe. After the sampling bag is connected, open valves 5 and 6 on the sampling bag; Step 2: Put the upper cover on the mouth of the sampling barrel and make the upper cover and the sampling barrel sealed; Step 3: Connect the sampling line to the sample port at valve 1 on the upper cover, and connect the vent line to the alkali solution barrel or dedicated venting system at valve 2; Step 4: Use a vacuum tube to connect the vacuum inlet of the upper cover to the vacuum pump, and connect the positive pressure gas pump to the gas inlet; Step 5: Before use, all valves on the upper cover are in the closed state; Step 6. Open valve 3 and start the vacuum pump. When the pressure in the sampling barrel drops to the required level, close valve 3 and the vacuum pump and check if the sampling barrel is leaking. If so, find the cause and continue until there is no leakage. Step 7. Open valve 3, start the vacuum pump to evacuate the sampling barrel, then slowly open valve 1 to allow the sample gas to enter the sampling bag under negative pressure. After the sampling bag is completely inflated, close valve 1, open valve 2, open valve 4, start the positive pressure gas pump to slowly inflate the sampling barrel, observe the pressure gauge indication and the amount of gas in the sampling bag, and after the gas in the sampling bag is completely discharged, quickly close valve 2, the positive pressure gas pump, and valve 4 in sequence. Step 8. Repeat step 7 at least 5 times; Step 9. After sampling is completed, close valve 1 and valve 2; remove the connecting pipelines at the gas inlet and the vacuum inlet, open valve 4, let air enter the sampling barrel until the pressure is balanced with the atmosphere, remove the upper cover, close valve 5 and valve 6 of the sampling bag, separate the sampling bag from pipeline connector 1 and pipeline connector 2, and the sampling is completed in one step.

4. An analysis system for trace sulfur in high-sulfur gas, characterized in that: The invention comprises a gas chromatograph and the sampling device for trace sulfur in high-sulfur gas according to claim 1.

5. The analysis system for trace sulfur in high-sulfur gas according to claim 4, characterized in that: The gas chromatograph includes an injection system, a chromatographic column, a heart-cutting assembly and a detector. The injection system includes a selection valve, a quantitative tube and a carrier gas tube. The selection valves are connected by a sample gas tube. In the injection system, both ends of the quantitative tube are connected to the selection valve, the carrier gas tube is connected to the selection valve, the selection valve is connected to the chromatographic column, the chromatographic column outlet is connected to the heart-cutting assembly, and the heart-cutting assembly outlet is connected to the detector.

6. The analysis system for trace sulfur in high-sulfur gas according to claim 5, characterized in that: The selection valve has a first state and a second state. When the selection valve is switched to the first state, the gas in the sample gas tube can pass through the quantitative tube and directly discharge from the analysis system. When the selection valve is switched to the second state, the gas in the carrier gas tube can flow to the chromatographic column through the quantitative tube.

7. The analysis system for trace sulfur in high-sulfur gas according to claim 5, characterized in that: The chromatographic column and the heart-cutting assembly are arranged in a column box, and the column box is connected to a refrigerant through a control valve.

8. The analysis system for trace sulfur in high-sulfur gas according to claim 5, characterized in that: The detector is a SCD detector.

9. The analysis system for trace sulfur in high-sulfur gas according to claim 5, characterized in that: The chromatographic column is a capillary column.

10. An analysis method using the analysis system for trace sulfur in high-sulfur gas according to claim 6, characterized in that: The following steps are involved: Step 1: sampling gas through a sampling device; Step 2: After sampling is completed, connect the sampling bag to the sample input end of the selection valve, switch the selection valve to the first state, and the gas in the sample gas pipe can pass through the quantitative tube and directly discharge the analysis system to complete the sample gas sampling; Step 3: Switch the selection valve to the second state, bring out the sample gas in the quantitative tube through the carrier gas, and bring the sample gas of the set flow rate into the chromatographic column through the flow controller, and then enter the heart cutting component. By changing the gas flow direction, the high content of hydrogen sulfide in the sample is removed, and other trace components are introduced into the detector.

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