A device system and method for detecting sulfur isotopes of organic sulfides in natural gas

Abstract

The application relates to a device system and a method for detecting the sulfur isotopes of organic sulfides in natural gas. The device system comprises a preset chemical trap and a hydrogen sulfide adsorption trap coupled with a heating device, which removes impurities in the natural gas, avoids occupying the effective enrichment space of the organic sulfides in the cold trap, adopts two-stage cold traps, and can effectively enrich and detect and analyze the organic sulfides. The device system has high reliability, high automation degree and simple operation, can be combined with a chromatography-stable isotope mass spectrometer to detect and analyze the sulfur isotopes, and provides a new way for researching the causes, sources and generation mechanism of the sulfur-containing natural gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geochemistry, and particularly relates to a device system and method for detecting sulfur isotopes of organic sulfides in natural gas. BACKGROUND

[0002] In oil and gas geological exploration, stable sulfur isotope detection technology is widely used in oil and gas source identification and oil and gas accumulation research. The pretreatment methods of different forms of sulfur compounds in geological bodies and the conditions of sulfur isotope detection instruments are different. At present, there are three methods for measuring sulfur isotopes: elemental analysis-stable isotope mass spectrometry, gas chromatography-stable isotope mass spectrometry, and gas chromatography-multiple collector inductively coupled plasma mass spectrometry.

[0003] Elemental analysis-stable isotope mass spectrometry can measure the sulfur isotopes of sulfides (acid volatile sulfide, H2S, pyrite), elemental sulfur, sulfates (calcium sulfate, barium sulfate), and organic matter (kerogen, crude oil components). Different forms of sulfur-containing samples have different sample preparation methods: for sulfides, they are converted into silver sulfide, cadmium sulfide or zinc sulfide solids by adding acid (Tuttle et al., 1986; Acholla and Orr, 1993; Giesemann, 1994; Li Liwu et al., 2007; Liu Wenhui et al., 2015; Shawar, 2018); for elemental sulfur, it is converted into copper sulfide powder by chloroform solvent extraction and the addition of copper powder (Zhang Zhongning et al., 2011); for sulfates, barium sulfate precipitates are formed by adding acid under the condition of barium chloride (Tuttle et al., 1986; Acholla and Orr, 1993; Zhao Rui et al., 1996; Gao Jianfei et al., 2020); for sulfur in kerogen / asphalt and other organic matter samples, acid and oxidizing agent are added to remove pyrite from the sample (Shawar et al., 2018, 2020). After preparation, the sample enters the elemental analyzer, is oxidized into SO2, and then enters the stable isotope mass spectrometer for sulfur isotope detection.

[0004] Gas chromatography-stable isotope mass spectrometry is to directly pass the purified carbonyl sulfide (O=C=S) into the mass spectrometer for ionization, and to detect ion fragments 32 S+, 33 S+and 34 S+, to obtain the isotopic value of sulfur (Hattori, 2015). This technology is only applicable to one compound (COS) and cannot be applied to other organic sulfur compounds in natural gas, and its application is very limited.

[0005] Gas chromatography-multiple collector inductively coupled plasma mass spectrometry can detect the sulfur isotope of a single organic sulfur compound, and the main principle of the method is that after the organic sulfur compound is separated by a gas chromatograph, the analyte is transmitted to a multiple collector inductively coupled plasma mass spectrometry system through a heated transmission line, and the system measures the sulfur isotope composition of a single compound peak. The multiple collector inductively coupled plasma mass spectrometry has high resolution and can analyze the delta 34S value of a single organic sulfur compound at the picomole (pmol) level, so that the enrichment treatment requirement of the sample is not high, but the price is high, the maintenance is complicated, and the popularity is poor.

[0006] The stable isotope mass spectrometer has good popularity, but requires a larger amount and higher purity of the organic sulfur fraction, which puts higher requirements on the pretreatment of the organic sulfur compound. The sulfur-containing natural gas is rich in high-sulfur CO2 and H2S and other acid gases, and the concentration thereof can reach a percentage level, while the concentration of the organic sulfur compound is usually at a ppm level. CO2 and H2S have a similar enrichment temperature to the organic sulfur compound, and simultaneous enrichment will occupy the effective enrichment space of the organic sulfur compound in the cold trap; secondly, after the enrichment is completed, there is usually extremely high-sulfur hydrogen sulfide in the product, which will cause serious overload / tailing of the sulfur compound after entering the chromatographic column of the chromatograph, and seriously affect the measurement of the ppm content of the organic sulfur compound.

[0007] Therefore, in view of the deficiencies of the prior art, there is an urgent need to provide a device system with high reliability, high automation, simple operation and high efficiency in enriching organic sulfur compounds and detecting sulfur isotopes. SUMMARY

[0008] The purpose of the present application is to provide a device system and method for detecting the sulfur isotope of an organic sulfur compound in natural gas, which realizes efficient enrichment and purification of the organic sulfur compound from sulfur-containing natural gas, and combines a chromatograph-stable isotope mass spectrometer for sulfur isotope detection and analysis, thereby providing a new way for studying the origin, source and generation mechanism of sulfur-containing natural gas.

[0009] To achieve the purpose of the present application, the following technical solutions are adopted:

[0010] In a first aspect, the present application provides a device system for detecting the sulfur isotope of an organic sulfur compound in natural gas, which comprises a sample gas pipeline, a four-way valve, a chemical trap, a hydrogen sulfide adsorption trap, a constant temperature device, a water trap, a first cold trap, a second cold trap and a chromatograph-stable isotope mass spectrometer; the four-way valve is circumferentially provided with a first port, a second port, a third port and a fourth port;

[0011] The thermostat is provided with a first eight-way valve and a second eight-way valve, wherein the first eight-way valve is provided with an a port, a b port, a c port, a d port, an e port, an f port, a g port, and an h port in a circumferential direction; and the second eight-way valve is provided with a first port, a second port, a third port, a fourth port, a fifth port, a sixth port, a seventh port, and an eighth port in a circumferential direction.

[0012] The sample gas pipeline is connected to the fourth port of the four-way valve through a pipeline, and a flow controller is provided at the front end of the sample gas pipeline; the first port of the four-way valve is connected to the chemical trap through a pipeline; the two ends of the hydrogen sulfide adsorption trap are respectively connected to the chemical trap and the sixth interface of the second eight-way valve through pipelines; the two ends of the water trap are respectively connected to the fifth interface of the second eight-way valve and the g interface of the first eight-way valve through pipelines; the two ends of the first cold trap are respectively connected to the h interface and the c interface of the first eight-way valve through pipelines to form an injection path;

[0013] The port b of the first eight-way valve is connected to a first carrier gas pipeline via a pipeline, and both ends of the second cold trap are connected to the port a of the first eight-way valve and the eighth port of the second eight-way valve via pipelines, respectively, to form a first purge passage;

[0014] The second port of the four-way valve is connected to a second carrier gas pipeline through a pipeline to form a second purge passage;

[0015] The second interface of the second eight-way valve is connected to a third carrier gas pipeline via a pipeline, and the first interface is connected to the chromatography-stable isotope mass spectrometer via a pipeline to form a third purge passage;

[0016] The fourth port of the second eight-way valve is connected to a fourth carrier gas pipeline via a pipeline, and the third port is connected to the e port of the first eight-way valve via a pipeline to form a fourth purge passage;

[0017] The purge air inlet end of the water trap is connected to a fifth carrier gas pipeline through a pipeline to form a purge and water removal gas path.

[0018] The sulfur isotope detection device system provided by the present invention fundamentally removes acidic gases such as water, CO2 and H2S from natural gas through a preset chemical trap and a hydrogen sulfide adsorption trap coupled with a heating device, thereby avoiding crowding out the effective enrichment space of organic sulfides in the cold trap; a two-stage cold trap is adopted, the first cold trap has a larger inner diameter, which allows the enriched gas flow to pass quickly to achieve rapid pre-enrichment, and the second cold trap has a smaller inner diameter, close to the diameter of the chromatographic column, and the pre-enriched fraction is secondary enriched in the second cold trap, which can make the organic sulfide components in the chromatographic column more concentrated and effectively reduce tailing, thereby achieving efficient enrichment and purification of organic sulfides from natural gas. Combined with chromatography-stable isotope mass spectrometry for sulfur isotope detection and analysis, it provides a new approach for studying the cause, source and generation mechanism of sulfur-containing natural gas.

[0019] Preferably, the inside of the chemical trap is provided with a water adsorbent and a carbon dioxide solidifying agent.

[0020] Preferably, the water adsorbent comprises magnesium perchlorate and / or calcium oxide.

[0021] Preferably, the carbon dioxide solidifying agent comprises sodium hydroxide and / or potassium hydroxide.

[0022] The water adsorbent and the carbon dioxide solidifying agent are reagents commonly used in the art and will not affect the detection object in the sample to be detected.

[0023] Preferably, the inside of the hydrogen sulfide adsorption trap is provided with a selective adsorbent.

[0024] Preferably, the selective adsorbent comprises 60-100 mesh silica gel particles, for example, it can be 60 mesh, 70 mesh, 80 mesh, 90 mesh or 100 mesh, but is not limited to the listed values, and other unlisted values within the value range are also applicable.

[0025] Preferably, the silica gel particles are obtained after treatment with a mixed solution of 50 g / L cadmium sulfate and 20 g / L boric acid, drying treatment, and glycerol aqueous solution wetting treatment.

[0026] Preferably, the glycerol aqueous solution is a 75% glycerol aqueous solution.

[0027] Preferably, the outside of the hydrogen sulfide adsorption trap is provided with a heating device.

[0028] Preferably, the heating device comprises a tubular heating furnace.

[0029] Preferably, the working temperature of the selective adsorbent is 78-82℃, for example, it can be 78℃, 79℃, 80℃, 81℃ or 82℃, but is not limited to the listed values, and other unlisted values within the value range are also applicable.

[0030] The hydrogen sulfide adsorption trap needs to be used with a heating device, so that the working temperature of the selective adsorbent is within a reasonable range, and hydrogen sulfide gas can be selectively adsorbed.

[0031] Preferably, the material of the water trap comprises Teflon.

[0032] Preferably, the working temperature of the constant temperature device is 160-180℃, for example, it can be 160℃, 165℃, 170℃, 175℃ or 180℃, but is not limited to the listed values, and other unlisted values within the value range are also applicable.

[0033] Preferably, the first cold trap and the second cold trap are both made of stainless steel tube with passivated inner surface.

[0034] Preferably, the inner diameter of the first cold trap is 0.5-1 mm, and the inner diameter of the second cold trap is 0.3-0.7 mm.

[0035] The inner diameter of the first cold trap is 0.5-1 mm, for example, it can be 0.5 mm, 0.75 mm, 0.8 mm or 1 mm, but is not limited to the listed values, and other unlisted values within the value range are also applicable.

[0036] The inner diameter of the first cold trap is 0.3-0.7 mm, for example, it can be 0.3 mm, 0.38 mm, 0.5 mm or 0.7 mm, but is not limited to the listed values, and other unlisted values within the value range are also applicable.

[0037] The first cold trap has a larger inner diameter, which allows the enriched gas stream to pass through quickly, achieving rapid pre-enrichment. The second cold trap has a smaller inner diameter, close to the diameter of the chromatographic column. The pre-enriched fraction is further enriched in the second cold trap, which can make the components of organic sulfides more concentrated in the chromatographic column, effectively reducing the tailing.

[0038] Preferably, the interior of the first cold trap and the second cold trap is provided with an adsorbent.

[0039] Preferably, the adsorbent includes any one of Hayesep N adsorbent, 5A molecular sieve, Tenax TA adsorbent or Tenax GR adsorbent, or a combination of at least two of them. Typical but non-limiting combinations include a combination of Hayesep N adsorbent and 5A molecular sieve, a combination of Tenax TA adsorbent and Tenax GR adsorbent, or a combination of Hayesep N adsorbent, 5A molecular sieve, Tenax TA adsorbent and Tenax GR adsorbent.

[0040] Preferably, the carrier gas introduced into the first carrier gas pipeline, the second carrier gas pipeline, the third carrier gas pipeline, the fourth carrier gas pipeline and the fifth carrier gas pipeline includes nitrogen and / or inert gas.

[0041] Preferably, the inert gas includes any one of helium, neon or argon.

[0042] Preferably, the pipeline includes a passivated quartz capillary tube.

[0043] In a second aspect, the present application provides a method for using the sulfur isotope detection device system of the first aspect, the method comprising the following steps:

[0044] The natural gas sample to be tested is subjected to impurity removal treatment, and the obtained impurity removal sample gas is subjected to first enrichment treatment and second enrichment treatment to obtain organic sulfides; and the obtained organic sulfides are subjected to sulfur isotope detection treatment to obtain a sulfur isotope detection value.

[0045] The method provided by the application can efficiently enrich and purify organic sulfides from natural gas for stable isotope detection by controlling the temperature, sample gas flow rate and sample injection time parameters in the first enrichment treatment and the second enrichment treatment.

[0046] Preferably, the enrichment temperatures of the first enrichment treatment and the second enrichment treatment are respectively -100 to -80℃, for example, can be -100℃, -95℃, -90℃, -85℃ or -80℃, but are not limited to the listed values, and other values not listed in the value range are also applicable.

[0047] Preferably, the thermal desorption temperatures after the first enrichment treatment and the second enrichment treatment are respectively 158-162℃, for example, can be 158℃, 159℃, 160℃, 161℃ or 162℃, but are not limited to the listed values, and other values not listed in the value range are also applicable.

[0048] The "thermal desorption" refers to that the first enrichment treatment and the second enrichment treatment are in a frozen enrichment state, and when the first enrichment treatment or the second enrichment treatment is completed, the frozen enrichment state is converted into a heating state, and the impurity removal sample gas is released from the first cold trap or the second cold trap in the heating state, that is, thermal desorption, and then enters the next device.

[0049] Preferably, the flow rate of the impurity removal sample gas in the first enrichment treatment is 15-20mL / min, for example, can be 15mL / min, 16mL / min, 18mL / min, 19mL / min or 20mL / min, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0050] Preferably, the sample injection time of the impurity removal sample gas in the first enrichment treatment is 30-300s, for example, can be 30s, 100s, 150s, 200s or 300s, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0051] Preferably, the flow rate of the impurity removal sample gas in the second enrichment treatment is 5-10mL / min, for example, can be 5mL / min, 6mL / min, 8mL / min, 9mL / min or 10mL / min, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0052] Preferably, the injection time of the impurity-removed sample gas during the second enrichment treatment is 30-60s, for example, 30s, 40s, 50s or 60s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] (1) The sulfur isotope detection device system provided by the present invention fundamentally removes acidic gases such as water, CO2 and H2S in natural gas by pre-setting a chemical trap and a hydrogen sulfide adsorption trap coupled with a heating device, thereby avoiding occupying the effective enrichment space of organic sulfides in the cold trap; a two-stage cold trap is adopted, the first cold trap has a larger inner diameter, which allows the enriched gas flow to pass quickly and achieve rapid pre-enrichment, and the second cold trap has a smaller inner diameter, which is close to the diameter of the chromatographic column, which can make the components of organic sulfides in the chromatographic column more concentrated and effectively reduce tailing;

[0055] (2) The sulfur isotope detection device system provided by the present invention has strong reliability, high degree of automation and simple operation. It can efficiently enrich and purify organic sulfides from natural gas through program control, and combine with chromatography-stable isotope mass spectrometry to perform sulfur isotope detection and analysis, providing a new approach for studying the cause, source and generation mechanism of sulfur-containing natural gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a schematic structural diagram of the first enrichment pathway provided in Example 1 of the present invention;

[0057] Figure 2 is a schematic structural diagram of the second enrichment pathway provided in Example 1 of the present invention;

[0058] Figure 3 Schematic diagram of the structure of the sample injection detection path provided in Example 1 of the present invention;

[0059] Figure 4 This is a graph showing the sulfur isotope detection results provided in Application Example 1 of the present invention;

[0060] Figure 5 This is a graph showing the sulfur isotope detection results provided in Application Example 2 of the present invention;

[0061] Figure 6 This is a graph showing the sulfur isotope detection results provided in Application Example 3 of the present invention;

[0062] Figure 7 This is a graph showing the sulfur isotope detection results provided in Application Example 4 of the present invention;

[0063] Figure 8 This is a graph showing the sulfur isotope detection results provided in Application Example 5 of the present invention;

[0064] Figure 9 is a sulfur isotope detection value result graph provided by the comparative application example 1 of the present application;

[0065] Figure 10 is a sulfur isotope detection value result graph provided by the comparative application example 2 of the present application;

[0066] Wherein: 1, sample gas pipeline; 2, four-way valve; 3, chemical trap; 4, hydrogen sulfide adsorption trap; 5, constant temperature device; 6, Teflon water trap; 7, first cold trap; 8, second cold trap; 9, chromatography-stable isotope mass spectrometer; 10, first eight-way valve; 11, second eight-way valve; 12, first carrier gas pipeline; 13, second carrier gas pipeline; 14, third carrier gas pipeline; 15, fourth carrier gas pipeline; 16, fifth carrier gas pipeline; 17, flow controller; 18, tubular heating furnace;

[0067] 201, first port; 202, second port; 203, third port; 204, fourth port;

[0068] 1001, a interface; 1002, b interface; 1003, c interface; 1004, d interface; 1005, e interface; 1006, f interface; 1007, g interface; 1008, h interface;

[0069] 1101, first interface; 1102, second interface; 1103, third interface; 1104, fourth interface; 1105, fifth interface; 1106, sixth interface; 1107, seventh interface; 1108, eighth interface. DETAILED DESCRIPTION

[0070] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application, and should not be regarded as specific limitations on the present application.

[0071] Example 1

[0072] The present embodiment provides a sulfur isotope detection device system for organic sulfides in natural gas, which comprises a sample gas pipeline 1, a four-way valve 2, a chemical trap 3, a hydrogen sulfide adsorption trap 4, a constant temperature device 5, a Teflon water trap 6, a first cold trap 7, a second cold trap 8, and a chromatography-stable isotope mass spectrometer 9; the four-way valve 2 is circumferentially provided with a first port 201, a second port 202, a third port 203, and a fourth port 204;

[0073] The inside of the constant temperature device 5 is provided with a first eight-way valve 10 and a second eight-way valve 11, the first eight-way valve 10 is circumferentially provided with an a interface 1001, a b interface 1002, a c interface 1003, a d interface 1004, an e interface 1005, an f interface 1006, a g interface 1007 and an h interface 1008; the second eight-way valve 11 is circumferentially provided with a first interface 1101, a second interface 1102, a third interface 1103, a fourth interface 1104, a fifth interface 1105, a sixth interface 1106, a seventh interface 1107 and an eighth interface 1108;

[0074] The b interface 1002 of the first eight-way valve 10 is connected with a first carrier gas pipeline 12 through a pipeline, and the two ends of the second cold trap 8 are respectively connected with the a interface 1001 of the first eight-way valve 10 and the eighth interface 1108 of the second eight-way valve 11 through pipelines, forming a first purging path;

[0075] The second port 202 of the four-way valve 2 is connected with a second carrier gas pipeline 13 through a pipeline, forming a second purging path;

[0076] The second interface 1102 of the second eight-way valve 11 is connected with a third carrier gas pipeline 14 through a pipeline, and the first interface 1101 is connected with the chromatography-stable isotope mass spectrometer 9 through a pipeline, forming a third purging path;

[0077] The fourth interface 1104 of the second eight-way valve 11 is connected with a fourth carrier gas pipeline 15 through a pipeline, and the third interface 1103 is connected with the e interface 1005 of the first eight-way valve 10 through a pipeline, forming a fourth purging path;

[0078] The purging gas inlet end of the Teflon water trap 6 is connected with a fifth carrier gas pipeline 16 through a pipeline, forming a water removal purging path;

[0079] The carrier gas in the first carrier gas pipeline 12, the second carrier gas pipeline 13, the third carrier gas pipeline 14, the fourth carrier gas pipeline 15 and the fifth carrier gas pipeline 16 is all helium; the pipeline includes a passivated quartz capillary tube;

[0080] The front end of the sample gas pipeline 1 is provided with a flow controller 17; the sample gas pipeline 1 is sequentially connected with the fourth port 204 of the four-way valve 2, the chemical trap 3, the hydrogen sulfide adsorption trap 4, the sixth interface 1106 of the second eight-way valve 11, the Teflon water trap 6, the g interface 1007 of the first eight-way valve 10, the first cold trap 7 and the c interface 1003 of the first eight-way valve 10, forming a sample inlet path; the sample inlet path is a first enrichment path, and the first carrier gas pipeline 12, the second carrier gas pipeline 13, the third carrier gas pipeline 14, the fourth carrier gas pipeline 15 and the fifth carrier gas pipeline 16 are all purging paths, and a structural schematic diagram is as shown in Figure 1as shown;

[0081] The first carrier gas pipeline 12 is connected to the b interface 1002 of the first eight-way valve 10, the first cold trap 7, the a interface 1001 of the first eight-way valve 10, the second cold trap 8, and the eighth interface 1108 of the second eight-way valve 11 in sequence to form a second enrichment passage, and the second carrier gas pipeline 13, the third carrier gas pipeline 14, the fourth carrier gas pipeline 15, and the fifth carrier gas pipeline 16 are all purge passages, as shown in the structural schematic diagram Figure 2

[0082] The first carrier gas pipeline 12 is connected to the b interface 1002 of the first eight-way valve 10, the a interface 1001 of the first eight-way valve 10, the second cold trap 8, the eighth interface 1108 of the second eight-way valve 11, the first interface 1101 of the second eight-way valve 11, and the chromatography-stable isotope mass spectrometer 9 to form a sample injection detection passage, and the second carrier gas pipeline 13, the third carrier gas pipeline 14, the fourth carrier gas pipeline 15, and the fifth carrier gas pipeline 16 are all purge passages, as shown in the structural schematic diagram Figure 3

[0083] Magnesium perchlorate and sodium hydroxide are arranged inside the chemical trap 3.

[0084] 80-mesh silica gel particles are arranged inside the hydrogen sulfide adsorption trap 4, the silica gel particles are obtained after being treated by a mixed solution of 50 g / L cadmium sulfate and 20 g / L boric acid, the silica gel particles are treated by drying and then treated by wetting with 75% glycerol water solution; a tubular heating furnace 18 is arranged outside the hydrogen sulfide adsorption trap 4, and the working temperature of the silica gel particles is 80℃.

[0085] The working temperature of the constant temperature device 5 is 170℃.

[0086] The first cold trap 7 and the second cold trap 8 are both stainless steel pipes with the inner surface treated by passivation; the inner diameter of the first cold trap 7 is 0.75 mm, and the inner diameter of the second cold trap 8 is 0.5 mm; Hayesep N adsorbent is arranged inside the first cold trap 7 and the second cold trap 8.

[0087] Example 2

[0088] The embodiment provides a device system for detecting sulfur isotopes of organic sulfides in natural gas, which is different from the embodiment 1 in that the inner diameter of the first cold trap 7 is adjusted to 0.13 mm, and the inner diameter of the second cold trap 8 is adjusted to 0.1 mm, and the rest is the same as the embodiment 1.

[0089] Example 3

[0090] ​​The embodiment provides a device system for detecting sulfur isotopes of organic sulfides in natural gas, which is different from the embodiment 1 in that, in addition to adjusting the inner diameter of the first cold trap 7 to 1.27 mm and the inner diameter of the second cold trap 8 to 1.25 mm, the rest is the same as the embodiment 1.

[0091] Comparative example 1

[0092] The comparative example provides a device system for detecting sulfur isotopes of organic sulfides in natural gas, which is different from the embodiment 1 in that, the first cold trap 7 and the second cold trap 8 are adjusted to only reserve the second cold trap 8, the connection relationship of each pipeline is adaptively adjusted, and the rest is the same as the embodiment 1.

[0093] Comparative example 2

[0094] The comparative example provides a device system for detecting sulfur isotopes of organic sulfides in natural gas, which is different from the embodiment 1 in that, the chemical trap 3 and the hydrogen sulfide adsorption trap 4 are not arranged, and the rest is the same as the embodiment 1.

[0095] Application example 1

[0096] The application example provides a method for applying the device system for detecting sulfur isotopes provided in the embodiment 1, and the method comprises the following steps.

[0097] The sample gas to be detected is subjected to impurity removal treatment, and the obtained impurity removal sample gas is subjected to first enrichment treatment and second enrichment treatment to obtain organic sulfides; the obtained organic sulfides are subjected to sulfur isotope detection treatment to obtain a sulfur isotope detection value; the enrichment temperature of the first enrichment treatment is-90 DEG C, the flow rate of the impurity removal sample gas is 18 mL / min, the sampling time is 200 s, and the first cold trap 7 is in a cold enrichment state; after the first enrichment treatment, the first cold trap 7 is converted from the cold enrichment state to a heating state, and the thermal desorption temperature is 160 DEG C; the enrichment temperature of the second enrichment treatment is-90 DEG C, the flow rate of the impurity removal sample gas is 8 mL / min, the sampling time is 50 s, and the second cold trap 8 is in a cold enrichment state; after the second enrichment treatment, the second cold trap 8 is converted from the cold enrichment state to a heating state, and the thermal desorption temperature is 160 DEG C.

[0098] In the sulfur isotope detection treatment, SO2 cylinder gas calibrated to the CDT standard by national standard substances (GBW04414, GBW04415) is used as reference gas, and the obtained sulfur isotope detection value result graph is as shown in Figure 4 As shown in the figure, the compound peak shape is normally distributed, and the peak intensity is good, and is between 6000-6500 mv.

[0099] The same natural gas sample was tested for 5 times in parallel, as shown in Table 1, wherein the average values of 5 times of detection of thiophene, ethyl sulfide, dimethyl disulfide and other compounds were 27.4 ‰, 18.26 ‰, 15.7 ‰ respectively, and the standard deviation was less than 0.5 ‰, the test stability was good, and the result was accurate.

[0100] Table 1

[0101]

[0102]

[0103] Application Example 2

[0104] The application example provides a method for applying the sulfur isotope detection device system provided in application example 1, and the difference from application example 1 is that the enrichment temperature of the first enrichment treatment is adjusted to -100℃, the flow of the impurity-removed sample gas is adjusted to 20 mL / min, the sampling time is adjusted to 30 s, and the thermal desorption temperature is adjusted to 158℃; the enrichment temperature of the second enrichment treatment is adjusted to -100℃, the flow of the impurity-removed sample gas is adjusted to 10 mL / min, the sampling time is adjusted to 30 s, and the thermal desorption temperature is adjusted to 158℃, and the rest are the same as application example 1.

[0105] The obtained sulfur isotope detection value result graph is as shown in Figure 5 The figure shows that the compound peak shape is good, but the peak intensity is obviously reduced, and the sulfur isotope detection values of the three organic sulfides are 27.34 ‰, 18.56 ‰ and 15.67 ‰ respectively, which are not much different from the average value of example 1.

[0106] Application Example 3

[0107] The application example provides a method for applying the sulfur isotope detection device system provided in application example 1, and the difference from application example 1 is that the enrichment temperature of the first enrichment treatment is adjusted to -80℃, the flow of the impurity-removed sample gas is adjusted to 15 mL / min, the sampling time is adjusted to 300 s, and the thermal desorption temperature is adjusted to 162℃; the enrichment temperature of the second enrichment treatment is adjusted to -80℃, the flow of the impurity-removed sample gas is adjusted to 5 mL / min, the sampling time is adjusted to 60 s, and the thermal desorption temperature is adjusted to 162℃, and the rest are the same as application example 1.

[0108] The obtained sulfur isotope detection value result graph is as shown in Figure 6 The figure shows that the compound peak shape is good, but the peak intensity is obviously reduced, and the sulfur isotope detection values of the three organic sulfides are 27.34 ‰, 18.56 ‰ and 15.67 ‰ respectively, which are not much different from the average value of example 1.

[0109] Application Example 4

[0110] The application example provides a method for applying the sulfur isotope detection device system provided in the application example 2, and the steps of the method are the same as those in the application example 1.

[0111] Since the inner diameters of the first cold trap and the second cold trap are too small, the amount of organic sulfur enriched in the cold traps is too small, and the obtained sulfur isotope detection value result graph is as shown in Figure 7 As shown in the graph, only the first compound peak appears, and the peak intensity is too low, and only the first organic sulfur compound sulfur isotope obtains a detection value of 11.04 ‰, which is greatly different from the average value in the first compound in the example 1.

[0112] Application example 5

[0113] The application example provides a method for applying the sulfur isotope detection device system provided in the application example 3, and the steps of the method are the same as those in the application example 1.

[0114] Since the inner diameters of the first cold trap and the second cold trap are too large, the peak shape of the organic sulfur compound appears serious tailing, the peak time is delayed, and the peak intensity is obviously reduced, and the obtained sulfur isotope detection value result graph is as shown in Figure 8 As shown in the graph, the sulfur isotope detection values of the three organic sulfur compounds are 22.32 ‰, 13.17 ‰ and 12.01 ‰, respectively, which are greatly different from the average value in the example 1.

[0115] Comparative application example 1

[0116] The comparative application example provides a method for applying the sulfur isotope detection device system provided in the comparative example 1, and the steps of the method are different from those in the application example 1 in that there is no first enrichment processing step, and the rest are the same as those in the application example 1.

[0117] Compared with the two-step enrichment processing, the step of directly performing one-step enrichment processing will result in that the amount of the enriched organic sulfur compound is too low, and the obtained sulfur isotope detection value result graph is as shown in Figure 9 As shown in the graph, the compound peak intensity is obviously reduced, the sulfur isotope detection values of the three organic sulfur compounds are 22.39 ‰, 14.14 ‰ and 11.76 ‰, respectively, which are greatly different from the average value in the example 1.

[0118] Comparative application example 2

[0119] The comparative application example provides a method for applying the sulfur isotope detection device system provided in the comparative example 2, and the steps of the method are different from those in the application example 1 in that there is no impurity removal processing step, and the rest are the same as those in the application example 1.

[0120] Without the impurity removal processing, the water, CO2 and H2S and other acidic gases in the natural gas occupy the effective enrichment space of the organic sulfur compound in the cold trap, so that the hydrogen sulfide and other gases in the natural gas enter the mass spectrometer after enrichment, and the obtained sulfur isotope detection value result graph is as shown inFigure 10 As shown in the figure, a peak of hydrogen sulfide appears before the first peak of organic sulfide compound, the intensity is more than 35000mv, and the tailing is obvious, and the peak intensity of the target organic sulfide is too low to detect the sulfur isotope values of the three target organic sulfides.

[0121] In summary, the sulfur isotope detection device system provided by the present application fundamentally removes the acidic gases such as water, CO2 and H2S in natural gas by using the preset chemical trap and the hydrogen sulfide adsorption trap coupled with the heating device, so as to avoid occupying the effective enrichment space of the organic sulfide in the cold trap; the two-stage cold trap is adopted, the inner diameter of the first cold trap is larger, so that the enriched gas flow can pass through quickly to realize rapid pre-enrichment, and the inner diameter of the second cold trap is smaller and close to the diameter of the chromatographic column, so that the components of the organic sulfide in the chromatographic column are more concentrated, and the tailing is effectively reduced.

[0122] The sulfur isotope detection device system provided by the present application has high reliability, high automation degree and simple operation, can efficiently enrich and purify the organic sulfide from natural gas through program control, and can be combined with a chromatography-stable isotope mass spectrometer to perform sulfur isotope detection and analysis, thereby providing a new way for studying the origin, source and generation mechanism of sulfur-containing natural gas.

[0123] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the present application can be easily thought out by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A device system for the detection of sulfur isotopes of organic sulfur compounds in natural gas, characterized in that, The sulfur isotope detection device system comprises a sample gas pipeline, a four-way valve, a chemical trap, a hydrogen sulfide adsorption trap, a constant temperature device, a water trap, a first cold trap, a second cold trap and a chromatography-stable isotope mass spectrometer. The four-way valve is circumferentially provided with a first port, a second port, a third port and a fourth port. The constant temperature device is internally provided with a first eight-way valve and a second eight-way valve, the first eight-way valve is circumferentially provided with an a interface, a b interface, a c interface, a d interface, an e interface, an f interface, a g interface and an h interface, and the second eight-way valve is circumferentially provided with a first interface, a second interface, a third interface, a fourth interface, a fifth interface, a sixth interface, a seventh interface and an eighth interface. The sample gas pipeline is connected with the fourth port of the four-way valve through a pipeline, and the front end of the sample gas pipeline is provided with a flow controller; the first port of the four-way valve is connected with the chemical trap through a pipeline; the hydrogen sulfide adsorption trap is connected with the chemical trap and the sixth interface of the second eight-way valve through pipelines at both ends; the water trap is connected with the fifth interface of the second eight-way valve and the g interface of the first eight-way valve through pipelines at both ends; the first cold trap is connected with the h interface and the c interface of the first eight-way valve through pipelines at both ends, forming a sample inlet channel. The b interface of the first eight-way valve is connected with a first carrier gas pipeline through a pipeline, and the two ends of the second cold trap are connected with the a interface of the first eight-way valve and the eighth interface of the second eight-way valve through pipelines, forming a first purge channel. The second port of the four-way valve is connected with a second carrier gas pipeline through a pipeline, forming a second purge channel. The second interface of the second eight-way valve is connected with a third carrier gas pipeline through a pipeline, the first interface is connected with the chromatography-stable isotope mass spectrometer through a pipeline, forming a third purge channel. The fourth interface of the second eight-way valve is connected with a fourth carrier gas pipeline through a pipeline, and the third interface is connected with the e interface of the first eight-way valve through a pipeline, forming a fourth purge channel. The water trap is connected with a fifth carrier gas pipeline through a pipeline at the gas inlet end of the purge, forming a water removal gas channel.

2. The sulfur isotope detection device system of claim 1, wherein, The chemical trap is internally provided with a water adsorbent and a carbon dioxide solidifying agent.

3. The sulfur isotope detection device system of claim 2, wherein, The water adsorbent comprises magnesium perchlorate and / or calcium oxide.

4. The sulfur isotope detection device system of claim 2, wherein, The carbon dioxide solidifying agent comprises sodium hydroxide and / or potassium hydroxide.

5. The sulfur isotope detection device system of claim 1, wherein, The hydrogen sulfide adsorption trap is internally provided with a selective adsorbent.

6. The sulfur isotope detection device system of claim 5, wherein, The selective adsorbent comprises 60-100 mesh silica gel particles.

7. The sulfur isotope detection device system of claim 6, wherein, The silica gel particles are obtained after treatment with a mixed solution of cadmium sulfate and boric acid, drying treatment and glycerol aqueous solution wetting treatment.

8. The sulfur isotope detection device system of claim 1, wherein, The hydrogen sulfide adsorption trap is externally provided with a heating device.

9. The sulfur isotope detection device system of claim 5, wherein, The working temperature of the selective adsorbent is 78-82℃.

10. The sulfur isotope detection device system of claim 1, wherein, The working temperature of the constant temperature device is 160-180℃.

11. The sulfur isotope detection device system of claim 1, wherein, The first cold trap and the second cold trap are both stainless steel pipes with a passivated inner surface.

12. The sulfur isotope detection device system of claim 1, wherein, The inner diameter of the first cold trap is 0.5-1mm, and the inner diameter of the second cold trap is 0.3-0.7mm.

13. The sulfur isotope detection device system of claim 1, wherein, The first cold trap and the second cold trap are both provided with an adsorbent inside.

14. The sulfur isotope detection device system of claim 13, wherein, The adsorbent includes any one of Hayesep N adsorbent, 5A molecular sieve, Tenax TA adsorbent or Tenax GR adsorbent or a combination of at least two thereof.

15. The sulfur isotope detection device system of claim 1, wherein, The carrier gas introduced into the first carrier gas pipeline, the second carrier gas pipeline, the third carrier gas pipeline, the fourth carrier gas pipeline and the fifth carrier gas pipeline includes nitrogen and / or inert gas.

16. The sulfur isotope detection device system of claim 1, wherein, The pipeline includes a passivated quartz capillary.

17. A method of using the sulfur isotope detection device system of any one of claims 1-16, wherein, The method includes the following steps: The natural gas sample gas to be tested is subjected to impurity removal treatment, and the obtained impurity-removed sample gas is subjected to first enrichment treatment and second enrichment treatment to obtain organic sulfides; and the obtained organic sulfides are subjected to sulfur isotope detection treatment to obtain a sulfur isotope detection value.

18. The method of claim 17, wherein, The enrichment temperatures of the first enrichment treatment and the second enrichment treatment are -100 to -80℃, respectively.

19. The method of claim 17, wherein, The thermal desorption temperatures after the first enrichment treatment and the second enrichment treatment are 158-162℃, respectively.

20. The method of claim 17, wherein, The flow rate of the impurity-removed sample gas during the first enrichment treatment is 15-20 mL / min.

21. The method of claim 17, wherein, The sample injection time of the impurity-removed sample gas during the first enrichment treatment is 30-300 s.

22. The method of claim 17, wherein, The flow rate of the impurity-removed sample gas during the second enrichment treatment is 5-10 mL / min.

23. The method of claim 17, wherein, The sample injection time of the impurity-removed sample gas during the second enrichment treatment is 30-60 s.

Images