CN113777177B

CN113777177B - System and method for detecting sulfur compounds in gas

Info

Publication number: CN113777177B
Application number: CN202010520234.4A
Authority: CN
Inventors: 王晓琴; 周理; 李晓红; 沈琳; 韩慧; 王伟杰; 张镨
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2020-06-09
Filing date: 2020-06-09
Publication date: 2024-03-26
Anticipated expiration: 2040-06-09
Also published as: CN113777177A

Abstract

The application discloses a detection system and a detection method for sulfur compounds in gas, and belongs to the technical field of gas detection. The detection system includes: the sample retaining device comprises a first sample injection pipeline, a second sample injection pipeline, a third sample injection pipeline, a control valve, a sample storage bottle and a controller; the first end of the first sample injection pipeline is used for inputting natural gas, the second end of the first sample injection pipeline, the first end of the second sample injection pipeline and the first end of the third sample injection pipeline are connected through a control valve, the second end of the second sample injection pipeline is communicated with the GC-IMS, and the second end of the third sample injection pipeline is communicated with the sample storage bottle; the controller controls the third sample injection pipeline to switch connection or disconnection between the first sample injection pipeline and the second sample injection pipeline through a control valve; the controller is also used to control the GC-IMS start or stop. Because GC-IMS is small in size and convenient to carry, natural gas can be detected on site on line, and manpower and material resources are saved.

Description

System and method for detecting sulfur compounds in gas

Technical Field

The application relates to the technical field of gas detection, in particular to a detection system and a detection method for sulfur compounds in gas.

Background

Natural gas is increasingly important as a clean energy source in people's daily life. However, along withThe promulgated implementation of the natural gas product standard GB17820-2018, which specifies that the total content of sulfur compounds in natural gas should not exceed 20mg/m ³ . Therefore, it is necessary to detect sulfur compounds in natural gas to ensure that the total content meets product standards.

Currently, in the detection of sulfur compounds in natural gas, a gas chromatograph-sulfur luminescence detector is often used for sampling detection. That is, a part of natural gas is extracted from a transport pipe of natural gas as a test sample, and the test sample is transported to a laboratory and is detected by a gas chromatograph-sulfur luminescence detector, and the total content of sulfur compounds in the test sample can be determined by detection analysis.

However, since the natural gas needs to be collected as a test sample and the collected test sample needs to be transported to a laboratory for testing, a lot of manpower and material resources are consumed.

Disclosure of Invention

The application provides a detection system and a detection method for sulfur compounds in gas, which can solve the problem that a large amount of manpower and material resources are consumed in the related technology. The technical scheme is as follows:

In one aspect, there is provided a detection system for sulfur compounds in a gas, the detection system comprising: a sample retention device and a GC-IMS (Gas Chromatography-Ion Mobility Spectrometry ) analyzer, the sample retention device comprising a first sample line, a second sample line, a third sample line, a control valve, a sample storage vial, and a controller;

the first end of the first sample injection pipeline is used for inputting natural gas, the second end of the first sample injection pipeline, the first end of the second sample injection pipeline and the first end of the third sample injection pipeline are connected through the control valve, the second end of the second sample injection pipeline is communicated with the GC-IMS, and the second end of the third sample injection pipeline is communicated with the sample storage bottle;

the control valve and the GC-IMS are electrically connected with the controller, and the controller is used for controlling the first sample injection pipeline to be communicated with the third sample injection pipeline and disconnected with the second sample injection pipeline, or controlling the third sample injection pipeline to be communicated with the second sample injection pipeline and disconnected with the first sample injection pipeline, or controlling the first sample injection pipeline, the second sample injection pipeline and the third sample injection pipeline to be disconnected with each other through the control valve; the controller is also used to control the GC-IMS start or stop.

Optionally, the control valve comprises a first two-way valve and a second two-way valve;

the second end of the first sample injection pipeline is communicated with one end of the first two-way valve, the other end of the first two-way valve is respectively communicated with one end of the second two-way valve and the first end of the third sample injection pipeline, and the other end of the second two-way valve is communicated with the first end of the second sample injection pipeline;

the first two-way valve and the second two-way valve are electrically connected with the controller, and the controller is used for controlling the first two-way valve to be conducted and controlling the second two-way valve to be disconnected, or is used for controlling the first two-way valve to be disconnected and controlling the second two-way valve to be conducted, or is used for controlling the first two-way valve and the second two-way valve to be disconnected.

Optionally, the control valve comprises a three-way valve;

the second end of the first sample injection pipeline, the first end of the second sample injection pipeline and the first end of the third sample injection pipeline are communicated through the three-way valve;

the three-way valve is electrically connected with the controller, and the controller is used for controlling the three-way valve to conduct the first sample injection pipeline and the third sample injection pipeline, or conduct the third sample injection pipeline and the second sample injection pipeline, or disconnect the first sample injection pipeline, the second sample injection pipeline and the third sample injection pipeline.

Optionally, the sample retention device further comprises a pressure regulating valve, a first flowmeter, and a proportional regulating valve;

the pressure regulating valve, the first flowmeter and the proportional regulating valve are sequentially communicated with the second sampling pipe line, and are electrically connected with the controller;

the controller is used for adjusting the gas pressure in the second sample injection pipeline through the pressure regulating valve, and is also used for adjusting the opening of the proportional regulating valve based on the instantaneous flow acquired by the first flow meter.

Optionally, the sample retention device further comprises a first pressure sensor;

the first pressure sensor is communicated with the second sampling pipe line and is positioned between the pressure regulating valve and the first flowmeter, and the first pressure sensor is electrically connected with the controller;

the controller is used for controlling the pressure regulating valve to regulate the gas pressure in the second sample injection pipeline based on the pressure collected by the first pressure sensor.

Optionally, the sample retention device further comprises a housing, a temperature sensor, and a heating device;

the first sample injection pipeline, the second sample injection pipeline, the third sample injection pipeline, the control valve, the sample storage bottle, the controller, the temperature sensor and the heating device are all positioned in the shell;

The temperature sensor and the heating device are electrically connected with the controller, the temperature sensor is used for detecting the temperature in the shell, and the controller is used for controlling the heating device to adjust the temperature in the shell based on the temperature detected by the temperature sensor.

Optionally, the sample retention device further comprises a display screen, wherein the display screen is electrically connected with the controller, and the display screen is used for displaying collected parameters and setting control parameters based on the controller.

Optionally, the sample retention device further comprises an explosion proof box, and the controller, the temperature sensor and the display screen are all located in the explosion proof box.

Optionally, the sample retention device further comprises a blowdown filter, a blowdown line and a blowdown valve;

the sewage filter is communicated with the first sampling pipe, the bottom of the sewage filter is communicated with one end of the sewage pipe, the sewage valve is connected with the sewage pipe, the sewage valve is electrically connected with the controller, and the controller is used for controlling the on/off of the sewage valve.

Optionally, the sample retention device further comprises a displacement line and a displacement valve;

One end of the replacement pipeline is communicated with the sample storage bottle, the replacement valve is connected to the replacement pipeline and is electrically connected with the controller, and the controller is used for controlling the replacement valve to be switched on or off.

In another aspect, there is provided a method of detecting a sulfur compound in a gas, the method being applied to a detection system as described in any one of the above, the method comprising:

controlling the first sample injection pipeline to be communicated with the third sample injection pipeline so as to store a gas sample in the sample storage bottle;

after the sample storage bottle finishes gas storage, the first sample injection pipeline is controlled to be disconnected from the third sample injection pipeline, and the third sample injection pipeline is controlled to be communicated with the second sample injection pipeline so as to introduce the gas sample into the GC-IMS;

after the gas sample is completely introduced into the GC-IMS, the third sample injection pipeline is controlled to be disconnected from the second sample injection pipeline, and the GC-IMS is controlled to analyze the gas sample in a first state;

after the analysis is completed in the first state, the third sample injection pipeline is controlled to be communicated with the second sample injection pipeline, so that the gas sample is introduced into the GC-IMS again;

After the gas sample is completely introduced into the GC-IMS, the third sample injection pipeline is controlled to be disconnected from the second sample injection pipeline, and the GC-IMS is controlled to analyze the gas sample in a second state;

after the analysis is completed in the second state, a detection result of the sulfur compound in the gas sample is determined based on the analysis result in the first state and the analysis result in the second state.

Optionally, the controlling the first sample line to communicate with the third sample line to store a gas sample in the sample storage bottle further comprises:

controlling the first sample injection pipeline to be communicated with the third sample injection pipeline, and controlling the replacement valve to be conducted so as to store a gas sample in the sample storage bottle;

and after the replacement valve is conducted for a first preset time period, the replacement valve is controlled to be disconnected.

The technical scheme that this application provided can bring following beneficial effect at least:

the GC-IMS is adopted in the detection system of the sulfur compounds in the gas to detect the sulfides of the natural gas, and because the GC-IMS is generally small in size, the detection system of the sulfur compounds in the gas is convenient to carry, so that the detection system of the sulfur compounds in the gas can be carried to the site to carry out online detection on the natural gas, namely, the collected natural gas is not required to be transported to a laboratory to carry out detection, but the natural gas can be detected on the site when the natural gas is mined and transported, and therefore, the manpower and material resources can be saved. And through first sample injection pipeline, control valve and third sample injection pipeline, can store the natural gas that once gathers into storing the appearance bottle, later can carry the natural gas that stores in storing the appearance bottle to GC-IMS in two times through control valve and second sample injection pipeline and detect to can make GC-IMS two times detect the natural gas that gathers into storing the appearance bottle. Because the components of the natural gas collected into the sample storage bottle are the same, the detection results obtained by the GC-IMS are comprehensively analyzed, and then a representative analysis detection result can be obtained, namely the analysis detection result has reference significance.

Drawings

FIG. 1 is a schematic structural diagram of a system for detecting sulfur compounds in a first gas according to an embodiment of the present application;

FIG. 2 is a schematic structural diagram of a system for detecting sulfur compounds in a second gas according to an embodiment of the present disclosure;

FIG. 3 is a schematic structural diagram of a third system for detecting sulfur compounds in a gas according to an embodiment of the present disclosure;

FIG. 4 is a schematic structural diagram of a system for detecting sulfur compounds in a fourth gas according to an embodiment of the present disclosure;

FIG. 5 is a flow chart of a method for detecting sulfur compounds in a gas according to an embodiment of the present application;

FIG. 6 is a graph of calibration of sulfur compounds in a first gas provided in an embodiment of the present application;

FIG. 7 is a graph of calibration of sulfur compounds in a second gas provided in an embodiment of the present application;

FIG. 8 is a graph of calibration of sulfur compounds in a third gas provided in an embodiment of the present application;

fig. 9 is a graph of calibration of sulfur compounds in a fourth gas provided in an embodiment of the present application.

Reference numerals:

1: a sample retention device; 2: GC-IMS;3: a first sample line; 4: a second sample injection line; 5: a third sample line; 6: a control valve; 61: a first two-way valve; 62: a second two-way valve; 63: a three-way valve; 7: a sample storage bottle; 8: a controller; 9: a pressure regulating valve; 10: a first flowmeter; 11: a proportional control valve; 12: a first pressure sensor; 13: a housing; 14: a temperature sensor; 15: a heating device; 16: a display screen; 17: an explosion-proof box; 18: a blowdown filter; 19: a blow-down line; 20: a blow-down valve; 21: replacement line: 22: replacing the valve; 23: an explosion-proof fan; 24: a second pressure sensor; 25: a second flowmeter.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Before explaining the embodiments of the present application in detail, GC-IMS applied in the embodiments of the present application will be described.

Since GC-IMS requires alternating positive and negative off-field analysis of sulfur compounds in a sample during sulfide analysis by GC-IMS, a complete analysis is performed. That is, when sulfide analysis is performed by GC-IMS gas chromatography-ion mobility spectrometry, a part of sulfide (e.g., methyl sulfide, ethyl sulfide, etc.) can be analyzed only by positive off-site, another part of sulfide (e.g., hydrogen sulfide, carbonyl sulfide, methyl mercaptan, etc.) can be analyzed only by negative off-site, and GC-IMS can perform only one off-site analysis at a time, and cannot perform both off-site analyses at the same time. Therefore, the natural gas in the pipeline needs to be collected and stored to ensure that positive and negative off-fields are respectively detected on the same natural gas sample when sulfide detection is carried out through GC-IMS, so as to ensure the accuracy of detection results.

Fig. 1 is a schematic structural diagram of a system for detecting sulfur compounds in a gas according to an embodiment of the present application. Referring to fig. 1, the detection system includes: a sample retention device 1 and a GC-IMS2.

The sample retaining device 1 comprises a first sample injection pipeline 3, a second sample injection pipeline 4, a third sample injection pipeline 5, a control valve 6, a sample storage bottle 7 and a controller 8; the first end of the first sample injection pipeline 3 is used for inputting natural gas, the second end of the first sample injection pipeline 3, the first end of the second sample injection pipeline 4 and the first end of the third sample injection pipeline 5 are connected through a control valve 6, the second end of the second sample injection pipeline 4 is communicated with the GC-IMS2, and the second end of the third sample injection pipeline 5 is communicated with a sample storage bottle 7; the control valve 6 and the GC-IMS2 are electrically connected with the controller 8, and the controller 8 is used for controlling the first sample injection pipeline 3 to be communicated with the third sample injection pipeline 5 and disconnected with the second sample injection pipeline 4 through the control valve 6, or controlling the third sample injection pipeline 5 to be communicated with the second sample injection pipeline 4 and disconnected with the first sample injection pipeline 3, or controlling the first sample injection pipeline 3, the second sample injection pipeline 4 and the third sample injection pipeline 5 to be disconnected with each other; the controller 8 is also used to control the start or stop of the GC-IMS 2.

Wherein the first sample line 3 is a line for collecting natural gas in a pipeline, the second sample line 4 is a line for transporting stored natural gas into the GC-IMS2, and the third sample line 5 is a line for transporting collected natural gas into a sample storage bottle 7.

Wherein the control valve 6 is a valve for controlling the connection or disconnection among the first sample injection line 3, the second sample injection line 4 and the third sample injection line 5.

Wherein the sample storage bottle 7 is a member for storing a natural gas sample. The size and type of the sample storage bottle 7 may be selected according to the use requirements, for example, the sample storage bottle 7 may be a retention cylinder or the like.

Wherein the controller 8 is a means for transmitting an electric signal to the control valve 6 and the GC-IMS2 to control the communication path of the control valve 6 and the start or stop of the GC-IMS 2. The type of the controller 8 may be selected according to the use requirement, for example, the controller 8 may be a PLC (Programmable Logic Controller ) controller, a single chip microcomputer, or the like.

It should be noted that the chromatographic column included in the GC-IMS2 may be selected according to the use requirement. For example, a chromatographic column with a fast response to sulfide, that is, a chromatographic column, may be selected, and the GC-IMS2 can respond to sulfide rapidly, so that sulfide in natural gas can be separated efficiently. The GC-IMS2 can then use the mobility difference of different sulfides in the positive or negative off-field formed by the different sulfides to rapidly detect the different sulfides.

The controller 8 may control the start or stop of the GC-IMS2 by a control signal transmitted through a transmission line, that is, the controller 8 may send a start control signal or a stop control signal to the GC-IMS2 through the transmission line to control the start of the GC-IMS2 by the start control signal or control the stop of the GC-IMS2 by the stop control signal.

The value is stated that the GC-IMS2 detects the content of the sulfur compounds in the natural gas on line by a gas chromatography-ion migration combined technology, and the combined technology is improved in two-dimensional separation means, carrier gas type optimization and the like, so that the detection system of the sulfur compounds in the gas can be suitable for being used in places such as a natural gas purification plant, an input gas distribution station, a trade handover metering station and the like.

In this embodiment, when the detection system for sulfur compounds in gas is used to detect sulfur compounds in natural gas, an electrical signal may be sent to the control valve 6 by the controller 8, so that the control valve 6 is controlled by the electrical signal, so that the second end of the first sample injection pipeline 3 is communicated with the first end of the third sample injection pipeline 5 and disconnected from the first end of the second sample injection pipeline 4. At this time, the natural gas enters the first sample injection line 3 through the first end of the first sample injection line 3, and then enters the sample storage bottle 7 through the first sample injection line 3 and the third sample injection line 5. When the time of the natural gas entering the sample storage bottle 7 reaches the gas storage time of the sample storage bottle 7, the controller 8 sends an electrical signal to the control valve 6, so that the control valve 6 is controlled by the electrical signal, and the first end of the third sample injection pipeline 5 is communicated with the first end of the second sample injection pipeline 4 and disconnected from the second end of the first sample injection pipeline 3. At this time, the natural gas in the first sample injection line 3 does not enter the sample storage bottle 7 any more, and the natural gas stored in the sample storage bottle 7 enters the GC-IMS2 through the third sample injection line 5 and the second sample injection line 4. When the time of the natural gas entering the GC-IMS2 reaches the sample storage time of the GC-IMS2, the controller 8 sends an electrical signal to the control valve 6, so that the control valve 6 is controlled by the electrical signal, so that the first end of the third sample line 5 is disconnected from the first end of the second sample line 4, and the natural gas stored in the sample storage bottle 7 does not enter the GC-IMS 2. The GC-IMS2 will then perform a sub-sulphide analysis on the incoming natural gas at the first ex-field. When the analysis is completed in the first off-site condition, the controller 8 sends an electrical signal again to the control valve 6, so that the control valve 6 is controlled by the electrical signal, so that the first end of the third sample line 5 is again communicated with the first end of the second sample line 4, and then the natural gas stored in the sample storage bottle 7 is again introduced into the GC-IMS2 through the third sample line 5 and the second sample line 4. After the time of entering the GC-IMS2 reaches the sample storage time of the GC-IMS2, the controller 8 sends an electrical signal again to the control valve 6, so that the control valve 6 is controlled by the electrical signal, so that the first end of the third sample line 5 is disconnected from the first end of the second sample line 4 again, and at this time, the GC-IMS2 performs sulfide analysis on the entering natural gas under the second field. When the analysis under the second off-field is finished, the analysis result under the first off-field and the analysis result under the second off-field are combined, so that the content of sulfide in the natural gas stored in the sample storage bottle 7 can be determined.

Wherein the first off-field is a positive off-field and the second off-field is a negative off-field; or the first off-field is a negative off-field and the second off-field is a positive off-field. The gas storage time and the sample storage time may be stored in the controller 8 in advance, or of course, the first analysis time under the first separation field and the second analysis time under the second separation field may be stored in advance, so that the controller 8 can determine that the analysis is finished according to the two analysis times.

In the embodiment of the application, the GC-IMS2 is adopted in the detection system of the sulfur compounds in the gas to detect the sulfur compounds in the natural gas, and because the GC-IMS2 is usually small in volume, the detection system of the sulfur compounds in the gas is convenient and portable, so that the detection system of the sulfur compounds in the gas can detect the natural gas on site, namely the collected natural gas is not required to be conveyed to a laboratory for detection, but the natural gas can be detected on site when the natural gas is mined and conveyed, and therefore manpower and material resources can be saved. And through first sample injection pipeline 3, control valve 6 and third sample injection pipeline 5, can store the natural gas that once gathers into storing appearance bottle 7, later can carry the natural gas that stores in storing appearance bottle 7 into GC-IMS2 through control valve 6 and second sample injection pipeline 4 twice and detect to can make GC-IMS2 twice detect the natural gas that gathers into storing appearance bottle 7. Because the components of the natural gas collected into the sample storage bottle 7 are the same, the analysis and detection results obtained by the GC-IMS2 are comprehensively analyzed, and then a representative analysis and detection result can be obtained, namely the analysis and detection result has a reference meaning.

In some embodiments, referring to fig. 2, the control valve 6 includes a first two-way valve 61 and a second two-way valve 62; the second end of the first sample injection pipeline 3 is communicated with one end of a first two-way valve 61, the other end of the first two-way valve 61 is respectively communicated with one end of a second two-way valve 62 and the first end of a third sample injection pipeline 5, and the other end of the second two-way valve 62 is communicated with the first end of the second sample injection pipeline 4; the first two-way valve 61 and the second two-way valve 62 are electrically connected to the controller 8, and the controller 8 is configured to control the first two-way valve 61 to be turned on and the second two-way valve 62 to be turned off, or is configured to control the first two-way valve 61 to be turned off and the second two-way valve 62 to be turned on, or is configured to control the first two-way valve 61 and the second two-way valve 62 to be turned off.

It should be noted that the sizes and types of the first two-way valve 61 and the second two-way valve 62 may be selected according to the requirements of use, for example, the first two-way valve 61 and the second two-way valve 62 may be two-position electric two-way valves, adjustable electric two-way valves, and the like.

In addition, the second end of the first sample injection line 3 is connected to one end of the first two-way valve 61 by a threaded connection, a flange connection, or the like. For example, an external thread may be disposed on the second end of the first sample injection pipeline 3, an internal thread matching the external thread may be disposed on one end of the first two-way valve 61, and the second end of the first sample injection pipeline 3 and one end of the first two-way valve 61 may be communicated in a threaded connection manner.

The communication mode between the other end of the first two-way valve 61 and the one end of the second two-way valve 62, the communication mode between the other end of the first two-way valve 61 and the first end of the third sample injection pipeline 5, the communication mode between the other end of the second two-way valve 62 and the first end of the second sample injection pipeline 4, which are the same as the above-mentioned communication modes, may be different, as long as the sealed communication can be realized, which is not repeated in this embodiment.

In this embodiment, when the natural gas in the pipeline needs to be collected, an electrical signal for controlling the connection can be sent to the first two-way valve 61 through the controller 8, and an electrical signal for controlling the disconnection can be sent to the second two-way valve 62, so as to control the connection of the first two-way valve 61 and the disconnection of the second two-way valve 62, at this time, the second end of the first sample injection pipeline 3 is communicated with the first end of the third sample injection pipeline 5 and disconnected from the first end of the second sample injection pipeline 4. When the natural gas in the sample storage bottle 7 needs to be detected, an electric signal for controlling the disconnection can be sent to the first two-way valve 61 through the controller 8, and an electric signal for controlling the connection can be sent to the second two-way valve 62, so that the first two-way valve 61 is controlled to be disconnected and the second two-way valve 62 is controlled to be connected, and at the moment, the first end of the third sample injection pipeline 5 is communicated with the first end of the second sample injection pipeline 4 and disconnected from the second end of the first sample injection pipeline 3. When the GC-IMS2 analyzes the gas sample of the natural gas, the controller 8 may send an electrical signal to the second two-way valve 62 to control the second two-way valve 62 to be opened, and at this time, the first end of the third sample injection line 5 is disconnected from the first end of the second sample injection line 4.

In other embodiments, referring to fig. 1, the control valve 6 comprises a three-way valve 63; the second end of the first sample injection line 3, the first end of the second sample injection line 4 and the first end of the third sample injection line 5 are communicated through a three-way valve 63; the three-way valve 63 is electrically connected with the controller 8, and the controller 8 is used for controlling the three-way valve 63 to conduct the first sample injection pipeline 3 and the third sample injection pipeline 5, or conduct the third sample injection pipeline 5 and the second sample injection pipeline 4, or disconnect the first sample injection pipeline 3, the second sample injection pipeline 4 and the third sample injection pipeline 5.

It should be noted that the size and the material of the three-way valve 63 may be selected according to the requirement, for example, the material of the three-way valve 63 may be cast iron, cast steel, stainless steel, etc.

The communication manner between the second end of the first sample injection pipeline 3 and the three-way valve 63, the communication manner between the first end of the second sample injection pipeline 4 and the three-way valve 63, and the communication manner between the first end of the third sample injection pipeline 5 and the three-way valve 63 may be the same as the above-mentioned communication manner, or may be different from the above-mentioned communication manner, so long as the sealed communication can be realized.

In this embodiment, when the natural gas in the pipeline needs to be collected, the controller 8 may send the first control electrical signal to the three-way valve 63 to control the valve core in the three-way valve 63 to rotate to a position where the second end of the first sample injection pipeline 3 is communicated with the first end of the third sample injection pipeline 5, and at this time, the second end of the first sample injection pipeline 3 is communicated with the first end of the third sample injection pipeline 5. When the natural gas in the sample storage bottle 7 needs to be detected, a second control electric signal can be sent to the three-way valve 63 through the controller 8 to control the valve core in the three-way valve 63 to rotate to a position for communicating the first end of the third sample injection pipeline 5 with the first end of the second sample injection pipeline 4, and at this time, the first end of the third sample injection pipeline 5 is communicated with the first end of the second sample injection pipeline 4. When the GC-IMS2 analyzes the gas sample of the natural gas, a third control electrical signal may be sent to the three-way valve 63 by the controller 8 to control the spool in the three-way valve 63 to rotate to a position to disconnect the second end of the first sample injection line 3 from the first end of the third sample injection line 5 and disconnect the first end of the third sample injection line 5 from the first end of the second sample injection line 4.

In some embodiments, referring to fig. 1 and 2, the sample retention device 1 further comprises a pressure regulating valve 9, a first flow meter 10 and a proportional regulating valve 11; the pressure regulating valve 9, the first flowmeter 10 and the proportional regulating valve 11 are sequentially communicated with the second sample injection pipeline 4, and the pressure regulating valve 9, the first flowmeter 10 and the proportional regulating valve 11 are electrically connected with the controller 8; the controller 8 is used for adjusting the gas pressure in the second sample injection pipeline 4 through the pressure regulating valve 9, and the controller 8 is also used for adjusting the opening of the proportional regulating valve 11 based on the instantaneous flow acquired by the first flowmeter 10.

The size and type of the pressure regulating valve 9 may be selected according to the requirements of the use, and for example, the pressure regulating valve 8 may be a ball valve, an eccentric rotary valve, or the like.

The pressure regulating valve 9 may not be electrically connected to the controller 8, that is, the pressure regulating valve 9 may be automatically controlled by the controller 8 or manually controlled by a technician. When manually controlled, the pressure regulating valve 9 may be a mechanical pressure reducing valve or the like.

In addition, the size and type of the first flowmeter 10 may be selected according to the use requirement, and for example, the first flowmeter 10 may be an electromagnetic flowmeter, a differential capacitive flowmeter, an inductive flowmeter, or the like.

The size and material of the proportional control valve 11 may be selected according to the requirements, for example, the material of the proportional control valve 11 may be carbon steel, stainless steel, or the like.

The values illustrate that the first flow meter 10 and the proportional control valve 11 may be integrally provided, i.e. the first flow meter 10 and the proportional control valve 11 may be replaced by a mass flow controller, which is electrically connected to the controller 8.

The first flowmeter 10 and the proportional control valve 11 may be adjusted by manual control, instead of being electrically connected to the controller 8. That is, at this time, the first flowmeter 10 and the proportional control valve 11 may be replaced by a rotameter, and the gas flow rate in the second sample introduction line 4 may be adjusted by manually adjusting the rotameter so that the gas flow rate in the second sample introduction line 4 satisfies the requirement.

Specifically, after the natural gas enters the second sample injection pipeline 4, the controller 8 will send an electrical signal to the pressure regulating valve 9, and then the pressure regulating valve 9 will convert the received electrical signal into a corner moment, and rotate a corresponding angle according to the corner moment, so as to regulate the gas pressure of the natural gas in the second sample injection pipeline 4. The first flowmeter 10 will collect the instantaneous flow of the natural gas flowing through it and send the instantaneous flow to the controller 8, then the controller 8 will compare the instantaneous flow with the preset flow, and generate an electrical signal according to the comparison result, and then transmit the electrical signal to the proportional control valve 11 to control the opening of the proportional control valve 11, so as to adjust the gas flow of the natural gas in the second sample injection pipeline 4. Therefore, the gas pressure and the gas flow of the natural gas finally entering the GC-IMS2 are in a better range, and the follow-up detection result obtained by the GC-IMS2 can be ensured to be more accurate.

It should be noted that the preset flow rate may be set according to the use requirement, for example, the preset flow rate may be 24 mL/min.

In some embodiments, referring to fig. 1 and 2, the sample retention device 1 further comprises a first pressure sensor 12; the first pressure sensor 12 is communicated with the second sample injection pipeline 4 and is positioned between the pressure regulating valve 9 and the first flowmeter 10, and the first pressure sensor 12 is electrically connected with the controller 8; the controller 8 is used for controlling the pressure regulating valve 9 to regulate the gas pressure in the second sample injection pipeline 4 based on the pressure acquired by the first pressure sensor 12.

The first pressure sensor 12 is a member that senses a gas pressure signal of the natural gas in the second sample line 4 and converts the gas pressure signal into an electric signal that can be output. The size and type of the first pressure sensor 12 may be selected according to the requirements of the application, for example, the first pressure sensor 12 may be a resistive strain gauge pressure sensor, a semiconductor strain gauge pressure sensor, a piezoresistive pressure sensor, an inductive pressure sensor, a capacitive pressure sensor, a resonant pressure sensor, etc.

The values illustrate that the first pressure sensor 12 is located between the pressure regulating valve 9 and the first flowmeter 10, that is, it indicates that the gas pressure detected by the first pressure sensor 12 is the gas pressure regulated by the pressure regulating valve 9, so that it can be determined whether the gas pressure regulated by the pressure regulating valve 9 meets the requirement. And it can also be shown that when the first flowmeter 10 is used for detecting the gas flow of the natural gas, the detected gas pressure of the natural gas is relatively stable, so that the problem of inaccurate flow detection caused by unstable gas pressure of the natural gas can be avoided.

Specifically, after the pressure regulating valve 9 is used to regulate the gas pressure of the natural gas in the second sample injection pipeline 4, the first pressure sensor 12 detects the gas pressure of the natural gas in the second sample injection pipeline 4, converts the detection result into an electrical signal, and sends the electrical signal to the controller 8, and the controller 8 determines whether the gas pressure of the natural gas in the second sample injection pipeline 4 meets the requirement at this time based on the electrical signal. If the gas pressure does not meet the requirement at this time, the controller 8 sends an electrical signal to the pressure regulating valve 9 to control the pressure regulating valve 9 to regulate until the gas pressure detected by the first pressure sensor 12 meets the requirement. In this way, it can be quickly known whether the gas pressure of the natural gas in the second sample injection pipeline 4 regulated by the pressure regulating valve 9 meets the requirement, and the pressure regulating valve 9 can be regulated more accurately by the detected result.

In some embodiments, referring to fig. 3 and 4, the sample retention device 1 further comprises a housing 13, a temperature sensor 14, and a heating device 15; the first sample injection pipeline 3, the second sample injection pipeline 4, the third sample injection pipeline 5, the control valve 6, the sample storage bottle 7, the controller 8, the temperature sensor 14 and the heating device 15 are all positioned in the shell 13; the temperature sensor 14 and the heating device 15 are electrically connected with the controller 8, the temperature sensor 14 is used for detecting the temperature in the shell 13, and the controller 8 is used for controlling the heating device 15 to adjust the temperature in the shell 13 based on the temperature detected by the temperature sensor 14.

The material and the size of the housing 13 may be set as long as the first sample injection line 3, the second sample injection line 4, the third sample injection line 5, the control valve 6, the sample storage bottle 7, the controller 8, the temperature sensor 14 and the heating device 15 are all located in the housing 13.

The values illustrate that, since the first sample injection pipeline 3, the second sample injection pipeline 4, the third sample injection pipeline 5, the control valve 6, the sample storage bottle 7, the controller 8, the temperature sensor 14 and the heating device 15 are all located in the shell 13, the first sample injection pipeline 3, the second sample injection pipeline 4, the third sample injection pipeline 5, the control valve 6, the sample storage bottle 7, the controller 8, the temperature sensor 14 and the heating device 15 can be isolated from the external environment, and the service lives of the first sample injection pipeline 3, the second sample injection pipeline 4, the third sample injection pipeline 5, the control valve 6, the sample storage bottle 7, the controller 8, the temperature sensor 14 and the heating device 15 are prolonged.

The temperature sensor 14 may be a thermocouple, a thermistor, a resistance type temperature detector, or the like, as long as it can detect temperature. Since the temperature sensor 14 is located in the housing 13, the temperature detected by the temperature sensor 14 is the temperature in the housing 13.

It should be noted that the heating device 15 is a member for heating, and the number of the heating devices 15 may be one or more. The size, type, etc. of the heating device 15 may be set according to the use requirement, and for example, the heating device 15 may be a heating plate, a heating pipe, etc.

It should be noted that when the outside air temperature is low, the temperature in the housing 13 is also low, which may result in a low gas temperature of the detected natural gas, and thus may result in an error in the detected result of the GC-IMS 2. At this time, the heating device 15 may be used to heat the air inside the housing 13, so that the temperature inside the housing 13 is within a reasonable temperature range, so that the gas temperature of the natural gas may be ensured not to be too low, and further the accurate result detected by the GC-IMS2 may be ensured.

Specifically, the temperature sensor 14 may detect the temperature inside the housing 13 in real time and transmit the detected temperature to the controller 8. When the controller 8 determines that the temperature detected by the temperature sensor 14 is less than or equal to the preset temperature, the heating device 15 is controlled to heat, so that the temperature inside the housing 13 gradually increases. Thereafter, when the controller 8 determines that the temperature detected by the temperature sensor 14 is greater than the preset temperature, the heating device 15 may be controlled to stop heating. In this way, the temperature inside the housing 13 can be ensured to be always in a more suitable temperature range, so that the gas temperature of the natural gas can be ensured not to be too low.

It should be noted that the preset temperature may be set according to the requirement of use, for example, the preset temperature may be 25 ℃.

In some embodiments, referring to fig. 3 and 4, the sample retention device 1 further comprises an explosion-proof blower 23, the explosion-proof blower 23 being located within the housing 13 and being electrically connected to the controller 8.

The explosion-proof blower 23 is a member for agitating the air in the housing 13 to make the air in the housing 13 flow rapidly. The size and type of the explosion-proof fan 23 can be selected according to the use requirement, for example, the explosion-proof fan 23 can be an explosion-proof asynchronous fan, an explosion-proof synchronous fan, an explosion-proof direct current fan and the like.

Specifically, when the heating device 15 heats under the control of the controller 8, the controller 8 also controls the explosion-proof fan 23 to rotate. Thus, the air in the shell 13 can flow rapidly through the anti-riot fan 23, so that the air heated by the heating device 15 can be rapidly emitted, and the temperature in the shell 13 can be ensured to be relatively uniform.

In some embodiments, referring to fig. 3 and 4, the sample retention device 1 further comprises a display screen 16, the display screen 16 being electrically connected to the controller 8, the display screen 16 being adapted to display the acquired parameters and to set the control parameters based on the controller 8.

The display screen 16 is a member for displaying the acquired parameters and setting the control parameters. Wherein the collected parameters may include the instantaneous flow collected by the first flow meter 10, the pressure collected by the first pressure sensor 12, and the temperature detected by the temperature sensor 14, and the display 16 may store the collected parameters so that a technician can learn the collected parameters in time through the display 16. The control parameters may be parameters controlling the control valve 6, parameters controlling the GC-IMS2, parameters controlling the pressure regulating valve 9, parameters controlling the proportional regulating valve 11, parameters controlling the heating means 15, and the display screen 16 may store the control parameters so as to send the control parameters to the controller 8 for controlling the corresponding components.

It should be noted that the size and type of the display screen 16 may be selected according to the requirement of use, for example, the display screen 16 may be a touch display screen or the like.

Taking the first pressure sensor 12 and the pressure regulating valve 9 as examples, the first pressure sensor 12 may transmit the collected pressure to the controller 8 in real time, and then the controller 8 may send the received pressure to the display screen 16 for displaying. The display screen 16 sends the set pressure of the first pressure sensor 12 stored in the display screen 16 to the controller 8, and then the controller 8 calculates the opening of the pressure regulating valve 9 through an intelligent PID (Proportion Integral Differential, proportional integral derivative) algorithm and controls the pressure regulating valve 9 according to the opening so that the difference between the pressure finally measured by the first pressure sensor 12 and the set pressure is smaller than a preset range, and meanwhile the controller 8 sends the opening to the display screen 16 for displaying, so that a technician can know the opening condition of the pressure regulating valve 9 in time.

It should be noted that the preset range may be set according to the use requirement, for example, the preset range may be 0 to 0.01Mpa (megapascal).

Taking the first flowmeter 10 and the proportional control valve 11 as examples, the first flowmeter 10 may transmit the collected instantaneous flow to the controller 8 in real time, and then the controller 8 may send the received instantaneous flow to the display screen 16 for displaying. The display screen 16 sends the set flow of the first flowmeter 10 stored in the controller 8, the controller 8 calculates the opening of the proportional control valve 11 through an intelligent PID algorithm, and controls the proportional control valve 9 according to the opening so that the difference between the instantaneous flow finally measured by the first flowmeter 10 and the set flow is smaller than a preset range, and meanwhile, the controller 8 sends the opening to the display screen 16 for displaying, so that a technician can know the opening of the proportional control valve 11 in time.

It should be noted that the preset range may be set according to the use requirement, for example, the preset range may be 0 to 1ml/min (milliliter/minute).

Taking the temperature sensor 14 and the heating device 15 as an example, the temperature sensor 14 may transmit the detected temperature to the controller 8 in real time, and then the controller 8 may send the received temperature to the display screen 16 for displaying. The display screen 16 sends the set temperature of the temperature sensor 14 stored in the controller 8, the controller 8 calculates the output power of the heating device 15 through an intelligent PID algorithm, and controls the heating device 15 according to the output power, so that the difference between the temperature finally measured by the temperature sensor 14 and the set temperature is smaller than the preset range, and meanwhile, the controller 8 sends the output power to the display screen 16 for displaying, so that a technician can know the heating condition of the heating device 15 in time.

It should be noted that the preset range may be set according to the use requirement, for example, the preset range may be 0 ° to 0.1 °.

In some embodiments, referring to fig. 3 and 4, the sample retention device 1 further comprises an explosion proof housing 17, and the controller 8, the temperature sensor 14, and the display screen 16 are all located within the explosion proof housing 17.

The material and the size of the explosion-proof tank 17 may be set, and for example, the material of the explosion-proof tank 17 may be aluminum metal, carbon fiber composite material, or the like.

By way of illustration, since natural gas is a flammable and explosive gas, placing the controller 8, temperature sensor 14 and display screen 16 in the explosion proof enclosure 17 prevents the controller 8, temperature sensor 14 and display screen 16 from being subjected to an explosion when the natural gas is exploded, thereby avoiding potential safety hazards.

It is noted that the control valve 6, the sample storage bottle 7, the pressure regulating valve 9, the first flowmeter 10, the proportional control valve 11, the first pressure sensor 12, the temperature sensor 14, and the heating device 15, which are located in the housing 13, are explosion-proof members. That is, the control valve 6, the sample storage bottle 7, the pressure regulating valve 9, the first flowmeter 10, the proportional control valve 11, the first pressure sensor 12, the temperature sensor 14, and the heating device 15 have an explosion-proof function, and therefore, the control valve 6, the sample storage bottle 7, the pressure regulating valve 9, the first flowmeter 10, the proportional control valve 11, the first pressure sensor 12, the temperature sensor 14, and the heating device 15 do not need to be placed in the explosion-proof tank 17.

In some embodiments, referring to fig. 1, 2, 3 and 4, the sample retention device 1 further comprises a blowdown filter 18, a blowdown line 19 and a blowdown valve 20; the blowdown filter 18 is communicated with the first sample injection pipeline 3, the bottom of the blowdown filter 18 is communicated with one end of the blowdown pipeline 19, the blowdown valve 20 is connected to the blowdown pipeline 19, the blowdown valve 20 is electrically connected with the controller 8, and the controller 8 is used for controlling the on or off of the blowdown valve 20.

The blowdown filter 18 is a member for filtering the natural gas in the first sample injection line 3 to remove impurities contained therein. The size and the location of the blowdown filter 18 may be set according to the requirements of the use, for example, the blowdown filter 18 may be disposed between the first end of the first sample injection line 3 and the control valve 6.

Further, the drain line 19 is a line for discharging the impurities filtered by the drain filter 18.

Further, the drain valve 20 is a valve for opening or shutting off the piping of the drain line 19. The size and type of the trapway 20 can be selected according to the needs of the user, for example, the trapway 20 can be a ball valve, a butterfly valve, etc.

It should be noted that the time for which the drain valve 20 is turned on may be set according to the use requirement. For example, the time for which the trapdoor 20 is turned on and off may be set depending on how much impurity is contained in the natural gas. Illustratively, the trapdoor 20 may be controlled to open once per month by the controller 8 to allow impurities in the trapway 19 to drain.

Specifically, when the natural gas enters the first sample injection pipeline 3, the natural gas first passes through the blowdown filter 18, at this time, the blowdown filter 18 filters the natural gas in the first sample injection pipeline 3, and the filtered impurities enter the blowdown pipeline 19. The drain valve 20 is then periodically controlled by the controller 8 to open to drain impurities from the drain line 19 out of the drain line 19. When the impurities in the sewage line 19 are completely discharged, the sewage valve 20 is controlled to be opened by the controller 8. Thus, the influence of impurities contained in the natural gas on the detection result can be avoided.

In some embodiments, referring to fig. 1, 2, 3 and 4, the sample retention device 1 further comprises a substitution line 21 and a substitution valve 22; one end of the displacement line 21 is communicated with the sample storage bottle 7, the displacement valve 22 is connected to the displacement line 21, the displacement valve 22 is electrically connected with the controller 8, and the controller 8 is used for controlling the on or off of the displacement valve 22.

The replacement line 21 is a line for replacing the natural gas stored in the sample storage bottle 7.

Wherein the displacement line 21 can communicate with the drain line 19 to form a drain together, such that the placement of the drain can be reduced.

Further, the substitution valve 22 is a valve for opening or closing the line of the substitution line 21. The size and type of the replacement valve 22 may be selected according to the requirements of the user, for example, the replacement valve 22 may be an electric straight-through valve, an electric ball valve, or the like.

Specifically, when the natural gas enters the sample storage bottle 7, the controller 8 controls the replacement valve 22 to be turned on, and at this time, the natural gas in the sample storage bottle 7 enters the replacement pipeline 21 and flows out through the replacement pipeline 21. When the replacement valve 22 is turned on for a preset time, the controller 8 controls the replacement valve 22 to be turned off, and then the natural gas is stored in the sample storage bottle 7. The natural gas is stored after the preset time, so that the stored natural gas can be ensured to be stable in gas flow state, and the follow-up detection is facilitated.

When the natural gas flowing through the pipeline at another moment is required to be detected, the controller 8 can control the replacement valve 22 to be turned on, and at this time, the natural gas stored in the sample storage bottle 7 in advance flows out through the replacement pipeline 21. When the replacement valve 22 is turned on for a preset time, the replacement valve 22 can be controlled to be turned off by the controller 8, and then the natural gas in the pipeline can be stored in the sample storage bottle 7 again, so that the next analysis can be conveniently performed.

In some embodiments, referring to fig. 1, 2, 3 and 4, the sample retention device 1 further comprises a second pressure sensor 24, the second pressure sensor 24 being in communication with the third sample line 5, the second pressure sensor 24 being in electrical communication with the controller 8; the second pressure sensor 24 is used to detect the gas pressure in the third sample line 5.

The second pressure sensor 24 is a member that senses a gas pressure signal of the natural gas in the third sample line 5 and converts the gas pressure signal into an electric signal that can be outputted. The size and type of the second pressure sensor 24 may be selected according to the requirements of the application, for example, the second pressure sensor 24 may be a resistive strain gauge pressure sensor, a semiconductor strain gauge pressure sensor, a piezoresistive pressure sensor, an inductive pressure sensor, a capacitive pressure sensor, a resonant pressure sensor, etc.

Specifically, after the natural gas in the first sample injection line 3 enters the third sample injection line 5, the second pressure sensor 24 detects the gas pressure of the natural gas in the third sample injection line 5, converts the detection result into an electrical signal, and sends the electrical signal to the controller 8, and the controller 8 determines the fluctuation of the gas pressure in the third sample injection line 5 at this time based on the electrical signal, so that whether the natural gas in the third sample injection line 5 flows or not can be determined according to the fluctuation of the pressure, and whether the gas is stored in the sample storage bottle 7 can be determined. In this way, the technician can be facilitated to know in time whether the natural gas is stored in the sample storage bottle 7.

In some embodiments, referring to fig. 1, 2, 3 and 4, the sample retention device 1 further comprises a second flow meter 25, the second flow meter 25 being in communication with the first sample injection line 3, and the second flow meter 25 being located between the blowdown filter 18 and the control valve 6; the second flowmeter 25 is used to collect instantaneous flow therethrough.

It should be noted that the size and type of the second flowmeter 25 may be selected according to the requirements of use, for example, the second flowmeter 25 may be a rotameter or the like.

In particular, the gas flow of the natural gas in the first feed line 3 can be detected and adjusted by means of the second flow meter 25. Thus, the natural gas in the first sample injection pipeline 3 can conveniently enter the sample storage bottle 7.

Fig. 5 is a flowchart of a method for detecting sulfur compounds in a gas according to an embodiment of the present application. Referring to fig. 5, the method is applied to the detection system shown in any one of fig. 1 to 4, and includes:

step 501: the first sample injection line 3 is controlled to communicate with the third sample injection line 5 to store the gas sample in the sample storage bottle 7.

In some embodiments, the display screen 16 may display a GC-IMS enabled interface, after which the display screen 16 may obtain setup instructions entered by the user in the GC-IMS enabled interface. That is, the user may input instructions to activate or deactivate the GC-IMS2 in the GC-IMS activation interface, such that the display 16 may obtain the instructions from the GC-IMS activation interface.

In some embodiments, the controller 8 may send a prepare signal to the GC-IMS2, and after the GC-IMS2 receives the prepare signal, the GC-IMS2 may enter a prepare state and send a determination signal to the controller 8. When the controller 8 receives the determination signal, it can determine that the GC-IMS2 is ready, and send the determination signal to the display screen 16, at this time, the technician may input a start command in the GC-IMS start interface displayed on the display screen 16, and then the controller 8 starts the GC-IMS2 according to the start command.

In some embodiments, when the controller 8 receives the start command, the controller 8 also sends an electrical signal to the control valve 6. When the control valve 6 receives the electrical signal, the control valve 6 controls the first sample injection pipeline 3 to be communicated with the third sample injection pipeline 5, and at this time, the natural gas in the first sample injection pipeline 3 flows into the sample storage bottle 7 for storage through the third sample injection pipeline 5.

Further, the method further comprises: the first sample injection pipeline 3 is controlled to be communicated with the third sample injection pipeline 5, and the replacement valve 22 is controlled to be communicated so as to store the gas sample in the sample storage bottle 7; after the replacement valve 22 is turned on for a first preset period of time, the replacement valve 22 is controlled to be turned off.

In some embodiments, the display screen 16 may display a parameter setting interface, after which the display screen 16 may obtain a first preset duration parameter entered by a user in the parameter setting interface. That is, the user may input a first preset duration parameter in the parameter setting interface, and thus the display screen 16 may obtain the first preset duration parameter from the parameter setting interface.

In some embodiments, the display screen 16 may send the first preset duration parameter entered to the controller 8, after which the controller 8 will control the replacement valve 22 based on the first preset duration parameter. If the on time of the replacement valve 22 is greater than or equal to the first preset duration parameter, the controller 8 controls the replacement valve 22 to be opened, and at this time, the sample storage bottle 7 is disconnected from the replacement pipeline 21, and the natural gas entering the third sample injection pipeline 5 is stored in the sample storage bottle 7. If the on time of the replacement valve 22 is less than the first preset time period, the controller 8 controls the replacement valve 22 to be continuously turned on, and at this time, the sample storage bottle 7 is communicated with the replacement pipeline 21, and the natural gas entering the sample storage bottle 7 flows out through the replacement pipeline 21, that is, the natural gas is not stored in the sample storage bottle 7. Therefore, the gas flow state of the natural gas stored in the sample storage bottle 7 for the first time can be stable, and the natural gas can be replaced and stored again through the sample storage bottle 7 conveniently.

The first preset duration parameter may be set according to a use requirement, for example, the first preset duration parameter may be 5 minutes, etc.

Step 502: after the sample storage bottle 7 finishes gas storage, the first sample injection pipeline 3 is controlled to be disconnected from the third sample injection pipeline 5, and the third sample injection pipeline 5 is controlled to be communicated with the second sample injection pipeline 4 so as to introduce a gas sample into the GC-IMS 2.

In some embodiments, the display screen 16 may display the parameter setting interface, and then, the display screen 16 may obtain the gas storage time of the sample storage bottle 7 input by the user in the parameter setting interface. That is, the user can input the air storage time of the sample storage bottle 7 in the parameter setting interface, so that the display screen 16 can obtain the air storage time parameter from the parameter setting interface.

In some embodiments, the display screen 16 may send the input gas storage time of the sample storage bottle 7 to the controller 8, and then the controller 8 may control the control valve 6 based on the gas storage time. If the actual gas storage time is equal to or longer than the input gas storage time, the controller 8 controls the control valve 6 to disconnect the first sample injection pipeline 3 from the third sample injection pipeline 5, and at this time, the natural gas in the first sample injection pipeline 3 cannot enter the third sample injection pipeline 5, and the gas storage bottle 7 completes gas storage.

When the first sample injection line 3 is disconnected from the third sample injection line 5, the controller 8 controls the control valve 6 so that the third sample injection line 5 is communicated with the second sample injection line 4, and the natural gas stored in the sample storage bottle 7 flows into the GC-IMS2 through the second sample injection line 4.

Step 503: after the gas sample is completely introduced into the GC-IMS2, the third sample introduction pipeline 5 is controlled to be disconnected from the second sample introduction pipeline 4, and the GC-IMS2 is controlled to analyze the gas sample in the first state.

Next, step 503 is described in detail.

In some embodiments, step 503 may be performed as follows steps (1) - (2).

(1) After the gas sample with the second preset duration is introduced into the GC-IMS2, the third sample injection pipeline 5 is controlled to be disconnected from the second sample injection pipeline 3.

In some embodiments, the display screen 16 may display a parameter setting interface, after which the display screen 16 may obtain a second preset duration parameter entered by the user in the parameter setting interface. That is, the user may input a second preset duration parameter in the parameter setting interface, such that the display screen 16 may obtain the second preset duration parameter from the parameter setting interface.

In some embodiments, the display screen 16 may send the second preset time period parameter to the controller 8, and the controller 8 may then control the control valve 6 based on the second preset time period parameter. If the third sample injection line 5 is connected to the second sample injection line 4 for a second predetermined period of time, the controller 8 controls the control valve 6 such that the third sample injection line 5 is disconnected from the second sample injection line 4, and the natural gas in the sample storage bottle 7 does not enter the GC-IMS2 through the second sample injection line 4, i.e., the gas sample is introduced into the GC-IMS 2.

The second preset duration parameter may be set according to a use requirement, for example, the second preset duration parameter may be 10 minutes, etc.

(2) And controlling the GC-IMS2 to analyze the gas sample for a third preset duration in the first state.

In some embodiments, the display screen 16 may display a parameter setting interface, after which the display screen 16 may obtain a third preset duration parameter entered by the user in the parameter setting interface. That is, the user may input a third preset time period parameter in the parameter setting interface, and thus the display screen 16 may acquire the third preset time period parameter from the parameter setting interface.

In some embodiments, the display 16 may send the third preset duration parameter to the controller 8, and then the controller 8 may control the analysis time of the GC-IMS2 based on the third preset duration parameter. If the analysis time of the GC-IMS1 is equal to the third preset duration parameter, the controller 8 controls the GC-IMS2 to stop the analysis, and the analysis in the first state is ended.

The first state may be set according to a user requirement, for example, the first state may be a positive departure, and the first state may also be a negative departure.

The third preset duration parameter may be set according to a use requirement, for example, the third preset duration parameter may be 10 minutes, etc.

Step 504: after the analysis is completed in the first state, the third sample injection line 5 is controlled to communicate with the second sample injection line 4 to introduce the gas sample into the GC-IMS2 again.

In some embodiments, after the controller 8 will control the GC-IMS2 to stop analyzing, the controller 8 will send an electrical signal to the control valve 6. When the control valve 6 receives the electrical signal, the control valve 6 controls the third sample line 5 to communicate with the second sample line 4, and the natural gas stored in the sample storage bottle 7 flows into the GC-IMS2 through the second sample line 4 again.

Step 505: after the gas sample is completely introduced into the GC-IMS2, the third sample introduction pipeline 5 is controlled to be disconnected from the second sample introduction pipeline 4, and the GC-IMS2 is controlled to analyze the gas sample in the second state.

Next, step 505 will be described in detail.

In some embodiments, step 505 may be performed as follows steps (1) - (2).

(1) After a fourth gas sample with preset duration is introduced into the GC-IMS2, the third sample injection pipeline 5 is controlled to be disconnected from the second sample injection pipeline 4.

In some embodiments, the display screen 16 may display a parameter setting interface, after which the display screen 16 may obtain a fourth preset duration parameter entered by the user in the parameter setting interface. That is, the user may input a fourth preset time period parameter in the parameter setting interface, and thus the display screen 16 may acquire the fourth preset time period parameter from the parameter setting interface.

In some embodiments, the display 16 may send the fourth predetermined time period parameter to the controller 8, and then the controller 8 may control the control valve 6 based on the fourth predetermined time period parameter. If the communication time between the third sample line 5 and the second sample line 4 is equal to the fourth preset duration parameter, the controller 8 controls the control valve 6 so that the third sample line 5 is disconnected from the second sample line 4, and the natural gas in the sample storage bottle 7 does not re-enter the GC-IMS2 through the second sample line 4.

The fourth preset duration parameter may be set according to a use requirement, for example, the fourth preset duration parameter may be 10 minutes, etc.

(2) And controlling the GC-IMS2 to analyze the gas sample for a fifth preset duration in the second state.

In some embodiments, the display screen 16 may display a parameter setting interface, after which the display screen 16 may obtain a fifth preset duration parameter entered by the user in the parameter setting interface. That is, the user may input a fifth preset time period parameter in the parameter setting interface, and thus the display screen 16 may acquire the fifth preset time period parameter from the parameter setting interface.

In some embodiments, the display 16 may send the fifth input preset duration parameter to the controller 8, and then the controller 8 may control the analysis time of the GC-IMS2 based on the fifth preset duration parameter. If the analysis time of the GC-IMS2 is equal to the fifth preset duration parameter, the controller 8 controls the GC-IMS2 to stop the analysis, and the analysis in the second state is ended.

The second state may be set according to a user requirement, for example, the second state may be a positive departure, and the second state may also be a negative departure.

The values illustrate that the first state and the second state are two different states, i.e. when the first state is positive off-field, the second state is negative off-field. When the first state is negative off-field, the second state is positive off-field.

The fifth preset duration parameter may be set according to a use requirement, for example, the fifth preset duration parameter may be 10 minutes, etc.

Step 506: after the analysis is completed in the second state, the detection result of the sulfur compound in the gas sample is determined based on the analysis result in the first state and the analysis result in the second state.

In some embodiments, the analysis performed in the second state indicates that the natural gas sample is subjected to positive off-field analysis and negative off-field analysis, respectively, so that detection analysis of sulfide in the natural gas sample can be ensured. Therefore, the analysis results in the first state and the analysis results in the second state are combined, and all the analysis results of the natural gas sample in the positive and negative fields can be obtained, so that the detection result of the sulfide in the natural gas sample can be determined.

In this embodiment of the present application, the first sample injection pipeline 3, the control valve 6 and the third sample injection pipeline 5 may store the natural gas collected once into the sample storage bottle 7, and then the natural gas stored in the sample storage bottle 7 may be transferred to the GC-IMS2 through the control valve 6 and the second sample injection pipeline 4 twice, and the natural gas stored in the sample storage bottle 7 may be detected in the first state and the second state respectively, so that the natural gas collected and stored in the sample storage bottle 6 may be detected in the GC-IMS2 twice. Because the components of the natural gas collected into the sample storage bottle 7 are the same, the analysis and detection results obtained by the GC-IMS2 are comprehensively analyzed, and then a representative analysis and detection result can be obtained, namely the analysis and detection result has a reference meaning.

In order to make the technical solutions and advantages of the present application more apparent, the following detailed description will be made by alternative embodiments.

Example 1

Referring to fig. 3, the detection system of sulfur compounds in the gas is powered on first, then the set temperature in the shell 13 is set on the display screen 16, the set flow corresponding to the first flowmeter 10 and the set pressure corresponding to the first pressure sensor 12 are set, meanwhile, the gas storage time, the first preset time period, the second preset time period, the third preset time period, the fourth preset time period and the fifth preset time period of the sample storage bottle 7 are set, and then the display screen 16 sends the set parameters to the controller 8. At this time, the controller 8 controls the output power of the heating device 15 according to the temperature detected by the temperature sensor 14 and the received set temperature to heat the air in the housing 13, so that the temperature deviation between the temperature in the housing 13 and the set temperature is within 0.1 degree. Further, the controller 8 controls the operation of the explosion-proof fan 23 so that the gas heated by the heating device 15 flows rapidly.

When the temperature within the housing 13 meets the requirements, the controller 8 will determine if the GC-IMS2 is ready. When the GC-IMS2 is ready to start, the technician can click on the start key on the display screen 16, at which time the display screen 16 will send the start command to the controller 8, and the controller 8 will control the three-way valve 63 according to the start command, so that the first sample line 3 is in communication with the third sample line 5. The controller 8 also controls the blow-down valve 20 and the replacement valve 22 to be communicated according to the starting instruction. At this time, the natural gas sample enters the first sample injection pipeline 3 from the first end of the first sample injection pipeline 3, passes through the blowdown filter 18, the second flowmeter 25, the three-way valve 63 and the second pressure sensor 24, reaches the sample storage bottle 7, and is then discharged through the replacement pipeline 21 and the replacement valve 22. At this time, the second pressure sensor 24 detects the pressure in the third sample line 5. If the controller 8 receives the pressure value transmitted by the second pressure sensor 24 as 0, it indicates that no natural gas flows in the third sample injection pipeline 5, and the controller 8 prompts the technician through the display screen 16.

When the switching-on time of the replacement valve 22 is a first preset time period, the controller 8 controls the switching-off of the replacement valve 22, and then the natural gas is stored in the sample storage bottle 7. When the gas storage time is the set gas storage time, the controller 8 controls the three-way valve 63 so that the second sample injection pipeline 4 is communicated with the third sample injection pipeline 5, and the first sample injection stage is started. At this stage, the controller 8 adjusts the opening of the pressure regulating valve 9 according to the set pressure corresponding to the first pressure sensor 12, so that the difference between the pressure detected by the first pressure sensor 12 and the set pressure is within the range of 0.01 Mpa. Then, the controller 8 adjusts the opening of the proportional control valve 11 according to the set flow corresponding to the first flowmeter 10, so that the instantaneous flow detected by the first flowmeter 10 is the set flow, and then the natural gas in the sample storage bottle 7 enters the GC-IMS 2. When the time for the natural gas in the sample storage bottle 7 to enter the GC-IMS2 is a set second preset time period, the controller 8 will stop adjusting the pressure regulating valve 9 and the proportional regulating valve 11, and will control the three-way valve 63 so as to disconnect the second sample injection line 4 from the third sample injection line 5. After that, the controller 8 sends an electrical signal to the GC-IMS2, and after the GC-IMS2 receives the electrical signal, the GC-IMS2 detects the natural gas sample for a third preset period of time in the positive departure.

After the detection time reaches the third preset duration, the GC-IMS2 stops the detection, and then enters the second sampling stage. At this stage, the controller 8 adjusts the opening of the pressure regulating valve 9 according to the set pressure corresponding to the first pressure sensor 12, so that the difference between the pressure detected by the first pressure sensor 12 and the set pressure is within the range of 0.01 Mpa. Then, the controller 8 adjusts the opening of the proportional control valve 11 according to the set flow corresponding to the first flowmeter 10, so that the instantaneous flow detected by the first flowmeter 10 is the set flow, and then the natural gas in the sample storage bottle 7 enters the GC-IMS 2. When the time for the natural gas in the sample storage bottle 7 to enter the GC-IMS2 is a set fourth preset time period, the controller 8 will stop adjusting the pressure regulating valve 9 and the proportional regulating valve 11, and will control the three-way valve 63 so as to disconnect the second sample injection line 4 from the third sample injection line 5. After that, the controller 8 sends an electrical signal to the GC-IMS2, and after the GC-IMS2 receives the electrical signal, the GC-IMS2 detects the natural gas sample for a fourth preset period of time under the negative ion field.

After the detection time reaches the fourth preset duration, the GC-IMS2 stops the detection. The above steps may then be repeated for the cyclic reciprocation detection analysis until the GC-IMS2 receives the stop command sent by the controller 8.

Example 2

Referring to fig. 3, the detection system of sulfur compounds in the gas is powered on first, then the set temperature in the shell 13 is set on the display screen 16, the set flow corresponding to the first flowmeter 10 and the set pressure corresponding to the first pressure sensor 12 are set, meanwhile, the gas storage time, the first preset time period, the second preset time period, the third preset time period, the fourth preset time period and the fifth preset time period of the sample storage bottle 7 are set, and then the display screen 16 sends the set parameters to the controller 8. At this time, the controller 8 controls the output power of the heating device 15 according to the temperature detected by the temperature sensor 14 and the received set temperature to heat the air in the housing 13, so that the temperature deviation between the temperature in the housing 13 and the set temperature is within 0.1 degree. Further, the controller 8 controls the operation of the explosion-proof fan 23 so that the air heated by the heating device 15 flows rapidly.

The technician clicks a start key on the display screen 16, after which the display screen 16 will send the start command to the controller 8. When the controller 8 receives the start-up instruction, the controller 8 sends a preparation instruction to the GC-IMS 2. If the controller 8 does not receive the determining instruction fed back by the GC-IMS2, the controller 8 sends a waiting instruction to the display 16 to prompt the technician to wait. If the controller 8 receives the determining instruction fed back by the GC-IMS2, the controller 8 controls the three-way valve 63 according to the determining instruction, so that the first sample line 3 is communicated with the third sample line 5. The controller 8 will also control the blow down valve 20 and the replacement valve 22 to be in communication based on the determined command. At this time, the natural gas sample enters the first sample injection line 3 from the first end of the first sample injection line 3, passes through the blowdown filter 18, the second flowmeter 25, the three-way valve 63 and the second pressure sensor 24, reaches the sample storage bottle 7, and is then discharged through the substitution line 21 and the substitution valve 22. At this time, the second pressure sensor 24 detects the gas pressure in the third sample injection line 5, if the controller 8 receives the gas pressure value transmitted from the second pressure sensor 24 as 0, it indicates that no natural gas flows in the third sample injection line 4, and the controller 8 prompts a technician through the display screen 16.

When the replacement valve 22 is turned on for a first preset period of time, the replacement valve 22 is turned off, and then natural gas is stored in the sample storage bottle 7. When the gas storage time is the set gas storage time, the controller 8 controls the three-way valve 63 so that the second sample injection pipeline 4 is communicated with the third sample injection pipeline 5, and the first sample injection stage is started. At this stage, the controller 8 adjusts the opening of the pressure regulating valve 9 according to the set pressure corresponding to the first pressure sensor 12, so that the difference between the pressure detected by the first pressure sensor 12 and the set pressure is within the range of 0.01 Mpa. Then, the controller 8 adjusts the opening of the proportional control valve 11 according to the set flow corresponding to the first flowmeter 10, so that the instantaneous flow detected by the first flowmeter 10 is the set flow, and then the natural gas in the sample storage bottle 7 enters the GC-IMS 2. When the time for the natural gas in the sample storage bottle 7 to enter the GC-IMS2 is a set second preset time period, the controller 8 will stop adjusting the pressure regulating valve 9 and the proportional regulating valve 11, and will control the three-way valve 63 so as to disconnect the second sample injection line 4 from the third sample injection line 5. The controller 8 then sends an electrical signal to the GC-IMS2, and the GC-IMS2, upon receiving the electrical signal, detects the natural gas sample in the positive off-site for a third predetermined period of time.

When the detection time reaches the third preset duration, the GC-IMS2 stops the detection, and at this time, the GC-IMS2 sends a determination instruction to the controller 8 again. If the controller 8 receives the determining instruction, it indicates that the analysis detection of the GC-IMS2 under the positive off-field has ended, and the GC-IMS2 can perform the negative off-field analysis detection. If the controller 8 does not receive the determination instruction, it indicates that the analysis detection of the GC-IMS2 in the positive off-field has not ended, and at this time, the GC-IMS2 cannot perform the negative off-field analysis detection.

Wherein, when the controller 8 receives the determining instruction, it enters the second sampling stage. At this stage, the controller 8 adjusts the opening of the pressure regulating valve 9 according to the set pressure corresponding to the first pressure sensor 12, so that the difference between the pressure detected by the first pressure sensor 12 and the set pressure is within the range of 0.01 Mpa. Then, the controller 8 adjusts the opening of the proportional control valve 11 according to the set flow corresponding to the first flowmeter 10, so that the instantaneous flow detected by the first flowmeter 10 is the set flow, and then the natural gas in the sample storage bottle 7 enters the GC-IMS 2. When the time for the natural gas in the sample storage bottle 7 to enter the GC-IMS2 is a set fourth preset time period, the controller 8 will stop adjusting the pressure regulating valve 9 and the proportional regulating valve 11, and will control the three-way valve 63 so as to disconnect the second sample injection line 4 from the third sample injection line 5. Then, the controller 8 sends an electrical signal to the GC-IMS2, and the GC-IMS2 detects the natural gas sample for a fourth preset period of time in the negative off-field after receiving the electrical signal.

When the detection time reaches the fourth preset duration, the controller 8 controls the three-way valve 63 so that the first sample injection line 3 and the third sample injection line 5 are continuously communicated. The controller 8 also controls the blow down valve 20 and the replacement valve 22 to be in communication. At this point the natural gas sample again enters the first sample line 3 from the first end of the first sample line 3 and passes through the blowdown filter 18, the second flow meter 25 and the three-way valve 63 and the second pressure sensor 24 to the sample storage bottle 7 and then is discharged through the substitution line 21 and the substitution valve 22. At this time, the second pressure sensor 24 detects the gas pressure in the third sample injection line 5, and if the controller 8 receives the gas pressure value transmitted from the second pressure sensor 24 as 0, it indicates that no natural gas flows in the third sample injection line 5, and the controller 8 prompts a technician through the display screen 16.

When the switching-on time of the replacement valve 22 is a first preset time period, the replacement valve 22 is opened, and the natural gas originally stored in the sample storage bottle 7 is replaced with new natural gas. And repeating the operation to detect and analyze the natural gas in the new reservoir.

The detection and analysis process of the GC-IMS2 on sulfide in the natural gas is as follows:

Several groups of natural gas samples with known sulfide component content were first analyzed by GC-IMS2 detection, then several groups of GC-IMS response values (i.e., peak intensities or peak areas) were obtained, and these GC-IMS response values (peak intensities) were recorded as shown in tables 1 to 4. Then, four calibration curves, namely four boltzmann curves, are drawn by taking the component content as an abscissa and the GC-IMS response value (peak intensity) as an ordinate, as shown in fig. 6, 7, 8 and 9, and then four calibration curve equations can be determined according to the four calibration curves, as shown in table 5. And then detecting and analyzing a natural gas sample with unknown sulfide component content by adopting GC-IMS2, and carrying the detected GC-IMS response value (peak intensity) into a calibration curve equation of sulfide with the same component, so as to calculate and obtain the component content.

Table 1H ₂ S content and peak intensity

TABLE 2 COS content and peak Strength

Table 3 CH ₄ S content and peak intensity

Table 4C ₂ H ₆ S content and peak intensity

TABLE 5 calibration Curve equation

The foregoing description of the preferred embodiments of the present application is not intended to limit the invention to the particular embodiments of the present application, but to limit the scope of the invention to the particular embodiments of the present application.

Claims

1. A method for detecting sulfur compounds in natural gas, wherein the method is applied to a detection system of sulfur compounds in gas, and the detection system comprises: the device comprises a sample retaining device (1) and a GC-IMS gas chromatography-ion mobility spectrometry analyzer (2), wherein the sample retaining device (1) comprises a first sample injection pipeline (3), a second sample injection pipeline (4), a third sample injection pipeline (5), a control valve (6), a sample storage bottle (7) and a controller (8);

the first end of the first sample injection pipeline (3) is used for inputting natural gas, the second end of the first sample injection pipeline (3), the first end of the second sample injection pipeline (4) and the first end of the third sample injection pipeline (5) are connected through the control valve (6), the second end of the second sample injection pipeline (4) is communicated with the GC-IMS (2), and the second end of the third sample injection pipeline (5) is communicated with the sample storage bottle (7);

the control valve (6) and the GC-IMS (2) are electrically connected with the controller (8), and the controller (8) is used for controlling the first sample injection pipeline (3) to be communicated with the third sample injection pipeline (5) and disconnected with the second sample injection pipeline (4) or controlling the third sample injection pipeline (5) to be communicated with the second sample injection pipeline (4) and disconnected with the first sample injection pipeline (3) or controlling the first sample injection pipeline (3), the second sample injection pipeline (4) and the third sample injection pipeline (5) to be disconnected with each other through the control valve (6); the controller (8) is further configured to control the start or stop of the GC-IMS (2);

The control valve (6) is a three-way valve (63);

the second end of the first sample injection pipeline (3), the first end of the second sample injection pipeline (4) and the first end of the third sample injection pipeline (5) are communicated through the three-way valve (63);

the three-way valve (63) is electrically connected with the controller (8), the controller (8) is used for controlling the three-way valve (63) to conduct the first sample injection pipeline (3) and the third sample injection pipeline (5), or conduct the third sample injection pipeline (5) and the second sample injection pipeline (4), or disconnect the first sample injection pipeline (3), the second sample injection pipeline (4) and the third sample injection pipeline (5), when natural gas in a pipeline is collected, a first control electric signal is sent to the three-way valve (63) through the controller (8), so that a valve core in the three-way valve (63) is controlled to rotate to a position for communicating the second end of the first sample injection pipeline (3) with the first end of the third sample injection pipeline (5), and at the moment, the second end of the first sample injection pipeline (3) is communicated with the first end of the third sample injection pipeline (5); when the natural gas in the sample storage bottle (7) is detected, a second control electric signal is sent to the three-way valve (63) through the controller (8) so as to control a valve core in the three-way valve (63) to rotate to a position for communicating the first end of the third sample injection pipeline (5) with the first end of the second sample injection pipeline (4), and at the moment, the first end of the third sample injection pipeline (5) is communicated with the first end of the second sample injection pipeline (4); when the GC-IMS (2) analyzes the gas sample of the natural gas, a third control electric signal is sent to the three-way valve (63) through the controller (8) so as to control the valve core in the three-way valve (63) to rotate to a position for disconnecting the second end of the first sample injection pipeline (3) from the first end of the third sample injection pipeline (5) and disconnecting the first end of the third sample injection pipeline (5) from the first end of the second sample injection pipeline (4);

The sample retaining device (1) further comprises a pressure regulating valve (9), a first flowmeter (10), a first pressure sensor (12) and a proportional regulating valve (11);

the pressure regulating valve (9), the first pressure sensor (12), the first flowmeter (10) and the proportional regulating valve (11) are sequentially communicated with the second sample injection pipeline (4), and the pressure regulating valve (9), the first pressure sensor (12), the first flowmeter (10) and the proportional regulating valve (11) are electrically connected with the controller (8);

the controller (8) is used for controlling the pressure regulating valve (9) to regulate the gas pressure in the second sample injection pipeline (4) based on the pressure acquired by the first pressure sensor (12), and the controller (8) is also used for regulating the opening of the proportional regulating valve (11) based on the instantaneous flow acquired by the first flowmeter (10);

the sample retention device (1) further comprises a housing (13), a temperature sensor (14) and a heating device (15);

the first sample injection pipeline (3), the second sample injection pipeline (4), the third sample injection pipeline (5), the control valve (6), the sample storage bottle (7), the controller (8), the temperature sensor (14) and the heating device (15) are all positioned in the shell (13);

The temperature sensor (14) and the heating device (15) are electrically connected with the controller (8), the temperature sensor (14) is used for detecting the temperature in the shell (13), and the controller (8) is used for controlling the heating device (15) to adjust the temperature in the shell (13) based on the temperature detected by the temperature sensor (14);

the sample retaining device (1) further comprises an explosion-proof fan (23), the explosion-proof fan (23) is located in the shell (13) and is electrically connected with the controller (8), the explosion-proof fan (23) is used for stirring air in the shell (13), and when the heating device (15) is used for heating under the control of the controller (8), the controller (8) further controls the explosion-proof fan (23) to rotate;

the sample retention device (1) further comprises a displacement line (21) and a displacement valve (22);

one end of the replacement pipeline (21) is communicated with the sample storage bottle (7), the replacement valve (22) is connected to the replacement pipeline (21), the replacement valve (22) is electrically connected with the controller (8), the controller (8) is used for controlling the replacement valve (22) to be conducted or disconnected, the replacement pipeline (21) is communicated with the sewage pipeline (19), when natural gas enters the sample storage bottle (7), the controller (8) controls the replacement valve (22) to be conducted, at the moment, the natural gas in the sample storage bottle (7) enters the replacement pipeline (21) and flows out through the replacement pipeline (21), and after the replacement valve (22) is conducted for a preset time, the controller (8) controls the replacement valve (22) to be disconnected, at the moment, the natural gas is stored in the sample storage bottle (7);

The sample retention device (1) further comprises a first pressure sensor (12) and a second pressure sensor (24);

the first pressure sensor (12) is communicated with the second sample injection pipeline (4) and is positioned between the pressure regulating valve (9) and the first flowmeter (10), and the first pressure sensor (12) is electrically connected with the controller (8);

the controller (8) is used for controlling the pressure regulating valve (9) to regulate the gas pressure in the second sample injection pipeline (4) based on the pressure acquired by the first pressure sensor (12);

the second pressure sensor (24) is communicated with the third sample injection pipeline (5), and the second pressure sensor (24) is electrically connected with the controller (8); the second pressure sensor (24) is for detecting a gas pressure in the third sample line (5), the method comprising:

controlling the first sample injection line (3) to communicate with the third sample injection line (5) to store a gas sample in the sample storage bottle (7);

after the sample storage bottle (7) finishes gas storage, the first sample injection pipeline (3) is controlled to be disconnected from the third sample injection pipeline (5), and the third sample injection pipeline (5) is controlled to be communicated with the second sample injection pipeline (4) so as to introduce the gas sample into the GC-IMS (2);

After the gas sample is completely introduced into the GC-IMS (2), controlling the third sample introduction pipeline (5) to be disconnected from the second sample introduction pipeline (4), and controlling the GC-IMS (2) to analyze the gas sample in a first state;

after the analysis is completed in the first state, controlling the third sample injection pipeline (5) to be communicated with the second sample injection pipeline (4) so as to introduce the gas sample into the GC-IMS (2) again;

after the gas sample is completely introduced into the GC-IMS (2), the third sample injection pipeline (5) is controlled to be disconnected from the second sample injection pipeline (4), and the GC-IMS (2) is controlled to analyze the gas sample in a second state, wherein the first state is a positive off-field, and the second state is a negative off-field;

2. The method according to claim 1, wherein the controlling the first sample line (3) communicates with the third sample line (5) for storing a gas sample in the sample storage bottle (7), the method further comprising:

Controlling the first sample injection pipeline (3) to be communicated with the third sample injection pipeline (5) and controlling the replacement valve (22) to be communicated so as to store a gas sample in the sample storage bottle (7);

and after the replacement valve (22) is conducted for a first preset time period, the replacement valve (22) is controlled to be disconnected.

3. The method according to claim 1, wherein the sample retention device (1) further comprises a display screen (16), the display screen (16) being electrically connected to the controller (8), the display screen (16) being adapted to display the acquired parameters and to set the control parameters based on the controller (8).

4. A method according to claim 3, wherein the sample retention device (1) further comprises an explosion proof box (17), the controller (8), the temperature sensor (14) and the display screen (16) being located within the explosion proof box (17).

5. The method according to claim 1, wherein the sample retention device (1) further comprises a blowdown filter (18), the blowdown line (19) and a blowdown valve (20);

the blowdown filter (18) is communicated with the first sample injection pipeline (3), the bottom of the blowdown filter (18) is communicated with one end of the blowdown pipeline (19), the blowdown valve (20) is connected with the blowdown pipeline (19), the blowdown valve (20) is electrically connected with the controller (8), and the controller (8) is used for controlling the on/off of the blowdown valve (20).