High-fidelity enrichment and separation apparatus, method and system for natural gas monomer components

Abstract

This invention provides a high-fidelity enrichment and separation device, method, and system for natural gas monomer components. The device includes: a separation component comprising a chromatographic column; an enrichment component connected to the output end of the chromatographic column, the enrichment component comprising multiple cold trap units connected in series, each cold trap unit having a specific enrichment temperature; and a collection component comprising a sample collection tube connected to the output end of the last cold trap unit in the enrichment component; wherein, along the flow direction of the natural gas sample in the enrichment component, the enrichment temperatures of the multiple cold trap units decrease sequentially. Based on the technical solution of this invention, by combining chromatographic separation and multi-stage cold trap purification and enrichment, the single components of natural gas after chromatographic separation can be further purified and enriched, achieving high-fidelity enrichment and separation of natural gas monomer components. This method offers good separation and enrichment effects, a simple operation process, and a short process time.

Description

Technical Field

[0001] This invention relates to the field of natural gas analysis and determination technology, and in particular to a high-fidelity enrichment and separation device, method and system for natural gas monomer components. Background Technology

[0002] In petroleum geology, natural gas typically refers to oilfield gas and gas field gas. Its composition is primarily gaseous low-molecular-weight hydrocarbons, with some non-hydrocarbon gases. The ratio of methane content to total hydrocarbon content (mainly methane, ethane, propane, butane, and pentane) in natural gas is called the "natural gas dryness coefficient." Generally, natural gas with a dryness coefficient >95% is called dry gas, and <95% is called wet gas. Studying the hydrocarbon components in natural gas provides organic geochemical parameters for understanding its origin and genesis. For dry gas, methane is the dominant component, with other hydrocarbon components present in low amounts, making them difficult to detect with commonly used chromatographic and isotopic instruments. Wet gas generally has low levels of propane and higher hydrocarbons, further limiting the available research indicators. Furthermore, the emergence of new technologies such as intramolecular carbon isotopes and cluster isotopes has placed higher demands on the analytical purity of individual components in natural gas.

[0003] Currently, traditional natural gas purification processes employ cryogenic distillation and membrane separation. Cryogenic distillation typically involves large-scale equipment and prolonged, repeated redistillation and fractionation, requiring low temperatures and high pressures, resulting in significant cost waste. Membrane separation yields natural gas components with low purity, the membranes cannot be reused, and the preparation process is time-consuming, complex, and costly, making it difficult to promote. Alternatively, cryogenic cold traps can be used to purify and separate natural gas components. However, because hydrocarbon components have similar molecular sizes, molecular weights, and boiling points, separation is extremely difficult, resulting in low purity.

[0004] Therefore, a novel high-fidelity enrichment and separation device and method for natural gas monomer components is needed to solve the problems existing in the above-mentioned separation methods. Summary of the Invention

[0005] To address the problems of complex operation, high cost, and poor separation effect of existing natural gas purification and separation methods, this application proposes a high-fidelity enrichment and separation device, method, and system for natural gas monomer components.

[0006] In a first aspect, the present invention provides a high-fidelity enrichment and separation device for natural gas monomer components, the separation device comprising:

[0007] Separation components, including a chromatographic column;

[0008] An enrichment component is connected to the output end of the chromatographic column. The enrichment component includes multiple cold trap units connected in series, and each cold trap unit has a certain enrichment temperature.

[0009] A collection assembly, comprising a sample collection tube connected to the output of the cold trap unit at the far end of the enrichment assembly;

[0010] Along the flow direction of the natural gas sample in the enrichment assembly, the enrichment temperature of the multiple cold trap units decreases sequentially.

[0011] In one implementation, it further includes:

[0012] A vacuum pump, which is connected via a three-way valve to the pipeline between the enrichment component and the collection component, has a vacuum pressure controller.

[0013] In one embodiment, a four-way valve is provided between the separation component and the enrichment component, and the four ports of the four-way valve are respectively connected to the output end of the separation component, the input end of the enrichment component, the carrier gas cylinder, and the venting pipeline.

[0014] In one embodiment, valve assemblies are provided on the pipelines between two adjacent cold trap units and between the last cold trap unit in the enrichment assembly and the collection assembly. The valve assemblies include a two-way valve and a three-way valve arranged sequentially along the flow direction of the natural gas sample.

[0015] In one embodiment, a three-way valve is provided at the input end of the cold trap unit, which is directly connected to the chromatographic column in the enrichment assembly.

[0016] In one embodiment, a thermal conductivity detector is provided at the output end of the chromatographic column.

[0017] Secondly, this invention proposes a high-fidelity enrichment and separation method for natural gas monomer components, applied to the aforementioned separation apparatus, comprising:

[0018] A natural gas sample is input into the chromatographic column of the separation component for chromatographic separation, while keeping the output end of the chromatographic column connected to the venting pipeline;

[0019] When the output of the chromatographic column detects a signal of the target component in the natural gas sample, the output of the chromatographic column is switched to the conducting enrichment component.

[0020] The target component is passed sequentially through multiple cold trap units connected in series and each having a certain enrichment temperature in the enrichment component, so that the target component is frozen and enriched in the last target cold trap unit among the multiple cold trap units it passes through in sequence;

[0021] After the target component is enriched, the input and output terminals of the corresponding target cold trap unit are closed, and the pipeline at the front end of the input terminal of the target cold trap unit is switched to venting.

[0022] After all the target components have been cryogenically enriched, the corresponding target components are collected in the same order as the order in which they were enriched.

[0023] In one implementation, the target components are collected in the same order as the order in which they were enriched, including:

[0024] The target cold trap unit located at the very end of all the target cold trap units currently enriched with the target component is designated as the target collection unit, and the output of the target collection unit is switched to the open state and kept in communication with the sample collection tube located at the rear end of the enrichment component.

[0025] The target collection unit is heated, causing the target component enriched therein to vaporize and enter the sample collection tube;

[0026] After the target component has been collected in the current target collection unit, the sample collection tube is replaced, and the next target collection unit to be collected is determined in the remaining target cold trap units.

[0027] In one embodiment, before heating the target collection unit, the method further includes:

[0028] Start the vacuum pump located between the enrichment component and the sample collection tube to evacuate the target collection unit and the sample collection tube;

[0029] After the vacuuming is complete, keep the target collection unit connected to the sample collection tube and close the vacuum pump's vacuuming end.

[0030] Thirdly, the present invention proposes a high-fidelity enrichment and separation system for natural gas monomer components, including the above-mentioned separation device and a control device electrically connected to the separation device, thereby possessing all the technical effects it has.

[0031] The above-mentioned technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved.

[0032] The present invention provides a high-fidelity enrichment and separation device, method, and system for natural gas monomer components, which, compared with the prior art, has at least the following advantages:

[0033] This invention discloses a high-fidelity enrichment and separation device, method, and system for natural gas monomer components. It employs a combination of chromatographic separation and multi-stage cold trap purification and enrichment, which can further purify and enrich the single components of natural gas after chromatographic separation, achieving high-fidelity enrichment and separation of natural gas monomer components. The separation and enrichment effect is good, the operation process is simple, and the process time is short. The separated natural gas components can be used for geochemical research such as stable carbon isotopes, providing more accurate and complete data. Attached Figure Description

[0034] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0035] Figure 1 A schematic diagram of the principle structure of the separation device of the present invention is shown;

[0036] Figure 2 The FID chromatogram of the natural gas sample before component separation is shown in this invention;

[0037] Figure 3 The FID chromatogram of the methane component after purification and enrichment of the natural gas sample according to the present invention is shown.

[0038] Figure 4 The TCD chromatogram of the natural gas sample before component separation is shown.

[0039] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not to scale.

[0040] Figure label:

[0041] 101-Separation component, 102-Injection port, 103-Chromatographic column, 104-Thermal conductivity detector, 105-Four-way valve, 106-Carrier gas cylinder, 201-Fifth three-way valve, 202-First stage cold trap, 203-First two-way valve, 204-First three-way valve, 205-Second stage cold trap, 206-Second two-way valve, 207-Second three-way valve, 208-Third stage cold trap, 209-Third two-way valve, 210-Third three-way valve, 211-Fourth stage cold trap, 212-Fourth two-way valve, 213-Fourth three-way valve, 214-Vacuum pump, 215-Vacuum pressure controller, 216-Sixth three-way valve, 217-Sample collection tube. Detailed Implementation

[0042] The invention will now be further described with reference to the accompanying drawings.

[0043] Example 1

[0044] Embodiments of the present invention provide a high-fidelity enrichment and separation device for natural gas monomer components, mainly used for purifying and enriching one or more monomer components in natural gas, including methane, ethane, propane, etc. The separation device of the present invention includes:

[0045] Separation component 101 includes chromatographic column 103;

[0046] The enrichment component is connected to the output end of the chromatographic column 103. The enrichment component includes multiple cold trap units connected in series, and each cold trap unit has a certain enrichment temperature.

[0047] The collection assembly includes a sample collection tube 217 connected to the output of the cold trap unit at the very end of the enrichment assembly.

[0048] Along the flow direction of the natural gas sample in the enrichment component, the enrichment temperature of multiple cold trap units decreases sequentially.

[0049] Specifically, refer to the attached diagram. Figure 1 The separation component 101 employs a gas chromatograph, which includes a Porapak-Q packed column 103. The input end of the column 103 is connected to the gas chromatograph's injection port 102, and it is used for chromatographic separation of natural gas components. The enrichment component is connected to the output end of the column 103 and is used to further separate and enrich the corresponding components after chromatographic separation by cold trap freezing enrichment. The enrichment component includes multiple cold trap units with enrichment temperature gradients, allowing the corresponding components in the natural gas sample to undergo multi-stage freezing through multiple cold trap units, ultimately enriching in the cold trap unit with the lowest temperature at the end, effectively improving the freezing enrichment effect. The collection unit can collect the corresponding components enriched in the respective cold trap units, thereby achieving the acquisition of the corresponding single-component sample.

[0050] In use, a natural gas sample is first introduced into the separation component 101. The natural gas sample undergoes chromatographic separation, and each individual component is sequentially output to the enrichment component for further cryogenic enrichment and purification. Specifically, the first output component sequentially passes through all the cold trap units in the enrichment component (see attached diagram). Figure 1 The four cold trap units (set up in the diagram) are gradually cooled and frozen, and the corresponding components are concentrated in the last cold trap unit and enriched by freezing (the enrichment temperature of the last cold trap unit is lower than the boiling point of the component), as shown in the attached diagram. Figure 1 The fourth-stage cold trap 211 in the process. Correspondingly, the components output in the second sequence pass sequentially through all the remaining cold trap units in the enrichment assembly (see attached figure). Figure 1The three cold trap units remaining after the last one are arranged in the diagram. The corresponding components are concentrated in the last cold trap unit and enriched by freezing (the enrichment temperature of the last cold trap unit is lower than the boiling point of the component), as shown in the attached diagram. Figure 1 The third-stage cold trap 208 is shown in the figure. Similarly, the other components output from this method will be sequentially enriched in their respective cold traps, as shown in the attached figure. Figure 1 The secondary cold trap 205 and the primary cold trap 202 in the system enable the separation and separate purification and enrichment of multiple single components in the same natural gas sample. After each component is enriched, the input and output ends of the cold trap containing it are immediately closed, firstly to prevent other impurity components from entering, and secondly to prevent the enriched components from escaping.

[0051] After the corresponding components are enriched in their respective cold traps, the collection process begins. Following the order of enrichment, the components enriched first are collected first; that is, the cold trap unit containing a component is closer to the collection assembly in the structural arrangement, and the earlier it is collected, as shown in the attached figure. Figure 1 The enrichment sequence is from the fourth-stage cold trap 211 to the first-stage cold trap 202, and the collection sequence is also from the fourth-stage cold trap 211 to the first-stage cold trap 202. During collection, the output end of the corresponding cold trap is opened and the cold trap is heated. The frozen and enriched components in the cold trap are vaporized and input into the sample collection tube 217. After collecting one component, a new sample collection tube 217 is replaced and the next component is collected in the same way.

[0052] It should be noted that, with reference to the attached diagram, Figure 1 The cold trap is U-shaped and made of stainless steel tubing. The bottom of the U-shape has a spiral structure (2-3 turns) to increase the contact area. The interior of the spiral section contains filler that does not adsorb hydrocarbons (such as silica gel, quartz sand, or quartz wool). The cold trap uses a liquid refrigerant, such as liquid nitrogen or a mixture of liquid nitrogen and alcohol.

[0053] Preferably, the number of cold trap units in the enrichment assembly is greater than the number of the single component of interest to be enriched and separated in the natural gas sample.

[0054] Furthermore, it also includes:

[0055] Vacuum pump 214, which is connected to the pipeline between enrichment component and collection component via sixth three-way valve 216, has vacuum pressure controller 215.

[0056] Specifically, vacuum pump 214 is mainly used to evacuate the pipelines of the separation unit to remove any impurities that may be present in the pipelines. Vacuuming is mainly performed before the natural gas sample is introduced and before each collection of the corresponding enriched components. Vacuum pressure controller 215 can detect the current vacuum pressure inside the pipeline in real time in order to control vacuum pump 214.

[0057] Furthermore, a thermal conductivity detector 104 is provided at the output end of the chromatographic column 103.

[0058] Specifically, as shown in the attached diagram. Figure 1 As shown, the thermal conductivity detector 104 is installed at the output end of the chromatographic column 103. Its function is to detect the output of each component of natural gas and the separation time of different components.

[0059] Furthermore, a four-way valve 105 is provided between the separation component 101 and the enrichment component. The four ports of the four-way valve 105 are respectively connected to the output end of the separation component 101, the input end of the enrichment component, the carrier gas cylinder 106, and the venting pipeline.

[0060] Specifically, refer to the attached diagram. Figure 1 The four-way valve 105 has four interchangeable interfaces, corresponding to the output of the separation component 101 (chromatographic column 103), the input of the enrichment component (cold trap unit), the carrier gas bottle 106, and the vent line, respectively. The carrier gas bottle 106 can be connected to the input of the enrichment component (cold trap unit) via the four-way valve 105 to provide carrier gas (helium); while the output of the separation component 101 (chromatographic column 103) can be connected to the vent line via the four-way valve 105. This allows other substances at the front end to be vented before the output of a specific target component, preventing the introduction of impurities into the enrichment component.

[0061] Furthermore, valve assemblies are installed on the pipelines between two adjacent cold trap units and between the last cold trap unit in the enrichment assembly and the collection assembly. The valve assemblies include two-way valves and three-way valves arranged sequentially along the flow direction of the natural gas sample.

[0062] Specifically, refer to the attached diagram. Figure 1 Valve assemblies are primarily used for pipeline control during the separation and enrichment of multiple single components. Specifically, the enrichment of a single component is performed in reverse order of the arrangement of multiple cold trap units, meaning the last cold trap unit enriches its corresponding component first. After the corresponding component is enriched, the corresponding cold trap unit needs to be kept relatively closed immediately to prevent other impurities from entering and the enriched component from flowing out. This is achieved by cutting off the connectivity between the pipelines before and after it.

[0063] For example, when the fourth-stage cold trap 211 in the cold trap unit has been enriched with the corresponding natural gas components, the pipelines before and after it need to be disconnected. The downstream pipeline is directly disconnected by closing the fourth two-way valve 212, while the fourth three-way valve 213 remains unchanged. However, while disconnecting the upstream pipeline, the connectivity of the downstream of the third-stage cold trap 208 during enrichment needs to be considered. Therefore, the third two-way valve 209 cannot be directly closed; instead, the third three-way valve 210 is switched to the venting state, connecting the downstream of the third-stage cold trap 208 to the outside atmosphere. Similarly, the corresponding valve assemblies of other cold traps are controlled in the same way.

[0064] Furthermore, a fifth three-way valve 201 is provided at the input end of the cold trap unit that is directly connected to the chromatographic column 103 in the enrichment component.

[0065] Example 2

[0066] Embodiments of the present invention provide a high-fidelity enrichment and separation method for natural gas monomer components, the separation method comprising the following steps:

[0067] Step S000: Evacuate the cold trap unit of the enrichment component and the corresponding pipelines, and then fill with carrier gas for protection.

[0068] Specifically, refer to the attached diagram. Figure 1 Before sample injection and analysis, close the input end of the first-stage cold trap 202 at the beginning of the enrichment component (place the fifth three-way valve 201 in the venting state, with one end of the fifth three-way valve 201 connected to the four-way valve 105 and the other end venting to the atmosphere). Then, connect the first two-way valve 203, the second two-way valve 206, the third two-way valve 209, the fourth two-way valve 212, and the first three-way valve 204, the second three-way valve 207, the third three-way valve 210, and the fourth three-way valve 213 sequentially, so that each stage of the first-stage cold trap 202, the second-stage cold trap 205, the third-stage cold trap 208, and the fourth-stage cold trap 211 are interconnected. Open the sixth three-way valve 216 to connect the vacuum pump 214 to the cold trap unit and the sample collection tube 217 respectively, and start the vacuum pump 214 to draw a vacuum.

[0069] After the vacuum of the entire system stabilizes, adjust the sixth three-way valve 216 to connect the vacuum pump 214 and the sample collection tube 217 to ensure that the sample collection tube 217 is under vacuum. At the same time, switch the fifth three-way valve 201 to the connected state, and connect the port of the four-way valve 105 corresponding to the carrier gas cylinder 106 to the port of the input end of the enrichment component (cold trap unit), so that the helium in the carrier gas cylinder 106 fills the entire enrichment component through the fifth three-way valve 201.

[0070] Step S100: Input the natural gas sample into the chromatographic column of the separation component for chromatographic separation, and keep the output end of the chromatographic column connected to the vent line;

[0071] Specifically, when the helium pressure of the enrichment component system is greater than or equal to atmospheric pressure, the fourth three-way valve 213 is placed in the venting state (one end of the fourth three-way valve 213 is connected to the fourth-stage cold trap 211, and the other end is connected to the atmosphere). Then, coolant at different temperatures is added to the corresponding cold trap units in sequence (first-stage cold trap 202: liquid nitrogen + alcohol, 253.15±10K; second-stage cold trap 205: liquid nitrogen + alcohol, 213.15±10K; third-stage cold trap 208: liquid nitrogen + alcohol, 163.15±10K; fourth-stage cold trap 211: liquid nitrogen, 77±10K). The four-way valve 105 is positioned at the output end of the chromatographic column 103, connecting to the vent pipeline and the input end of the cold trap unit (first-stage cold trap 202), connecting to the carrier gas cylinder 106. Natural gas samples are injected through the injection port 102, and the chromatographic column 103 in the gas chromatograph separates the different components of the natural gas, effectively separating natural gas components such as methane, ethane, propane, and carbon dioxide.

[0072] Step S200: When the output of the chromatographic column detects a signal of the target component in the natural gas sample, switch the output of the chromatographic column to the conducting enrichment component;

[0073] Step S300: The target component is passed sequentially through multiple cold trap units connected in series in the enrichment component, each with a certain enrichment temperature, so that the target component is frozen and enriched in the last target cold trap unit among the multiple cold trap units it passes through in sequence.

[0074] Specifically, based on the principle of chromatographic separation, the methane component is output first. When the thermal conductivity detector 104 at the output end of the chromatographic column 103 detects a methane signal, the four-way valve 105 is quickly placed in the sampling state, connecting the chromatographic column 103 and the cold trap unit. The carrier gas He blows the methane separated by the chromatograph through the four-way valve 105 and the fifth three-way valve 201 to the first-stage cold trap 202 (liquid nitrogen + alcohol, 253.15±10K) for primary cooling and purification, and then through the first two-way valve 203 and the first three-way valve 204 to the second-stage cold trap 205 (liquid nitrogen + alcohol). Alcohol (213.15±10K) is further cooled and purified in the third-stage cold trap 208 (liquid nitrogen + alcohol, 163.15±10K) via the second two-way valve 206 and the second three-way valve 207, while methane (CH4 boiling point 111.65K) passes smoothly. It is then cryogenically enriched in the fourth-stage cold trap 211 (liquid nitrogen, 77±10K) filled with packing material (such as silica gel, quartz sand, or quartz wool) via the third two-way valve 209 and the third three-way valve 210. The carrier gas He is discharged into the atmosphere via the fourth two-way valve and the fourth three-way valve 213. At this point, the fourth-stage cold trap 211 serves as the target cold trap unit for methane.

[0075] Step S400: After enriching the target component, close the input and output terminals of the corresponding target cold trap unit and switch the pipeline at the front end of the input terminal of the target cold trap unit to vent.

[0076] Specifically, after methane is frozen and enriched and before the subsequent component signals appear, the third three-way valve 210 at the front end of the fourth-stage cold trap 211 is placed in the venting state, and the fourth two-way valve 212 after the fourth-stage cold trap 211 is placed in the closed state. At this time, the methane is frozen and sealed in the fourth-stage cold trap 211 (liquid nitrogen 77±10K), and the liquid level of the cryo-fluid is raised for further freezing; at the same time, the cryo-fluid in the third-stage cold trap 208 is switched to use liquid nitrogen (77±10K).

[0077] Step S500: Repeat steps S300 to S400 to freeze-enrich other single components in the natural gas sample;

[0078] Step S510: Repeat steps S300 to S400 to enrich ethane by freezing;

[0079] Specifically, ethane is cryogenically enriched after methane. When the thermal conductivity detector 104 at the output of column 103 detects an ethane signal, the carrier gas He carries the separated ethane through a four-way valve 105 and a fifth three-way valve 201 into a first-stage cold trap 202 (liquid nitrogen + alcohol, 253.15±10K) for primary cooling and further purification. It is then further cooled and purified in a second-stage cold trap 205 (liquid nitrogen + alcohol, 213.15±10K) via a first two-way valve 203 and a first three-way valve 204. Ethane (C2H6 boiling point is 184.55K) passes through smoothly and is then cryogenically enriched in a third-stage cold trap 208 (liquid nitrogen, 77±10K) via a second two-way valve 206 and a second three-way valve 207. The carrier gas He is then discharged into the atmosphere through a third three-way valve 210.

[0080] After ethane is frozen and enriched and before the subsequent component signals appear, the second three-way valve 207 is placed in the venting state and the third two-way valve is placed in the closed state. At this time, the ethane is frozen in the third-stage cold trap 208 (77±10K), and the liquid level of the cryo-cooling fluid is raised for further freezing; at the same time, the cryo-cooling fluid in the second-stage cold trap 205 is switched to liquid nitrogen (77±10K).

[0081] Step S520: Repeat steps S300 to S400 to enrich propane by freezing;

[0082] Specifically, propane is cryogenically enriched after ethane. When the thermal conductivity detector 104 at the output end of the chromatographic column 103 detects a propane signal, the carrier gas He carries the propane separated by the chromatograph through a four-way valve 105 and a fifth three-way valve 201 into a primary cold trap 202 (liquid nitrogen + alcohol, 253.15±10K) for primary cooling and further purification. The propane is then cryogenically enriched in a secondary cold trap 205 (liquid nitrogen, 77±10K) via a first two-way valve 203 and a first three-way valve 204.

[0083] After propane (C3H8 boiling point is 231.05K) is enriched and before the subsequent component signals appear, switch the four-way valve 105 to the state where the carrier gas cylinder 106 is connected to the input end of the enrichment component (cold trap unit). Then, through the pure carrier gas purging line of the carrier gas cylinder 106, switch the first three-way valve 204 to the venting state and put the second two-way valve 206 in the closed state. At this time, the propane is frozen in the secondary cold trap 205 (77±10K), and the liquid level of the coolant is raised for further freezing.

[0084] Step S600: After all target components have been frozen and enriched, the corresponding target components are collected in the same order as the order in which they were enriched.

[0085] Step S610: Designate the last target cold trap unit among all target cold trap units currently enriched with the target component as the target collection unit, switch the output of the target collection unit to the open state and keep it connected to the sample collection tube located at the rear end of the enrichment component;

[0086] Step S620: Start the vacuum pump set between the enrichment component and the sample collection tube to evacuate the target collection unit and the sample collection tube; after evacuation is completed, keep the target collection unit and the sample collection tube connected and close the vacuum pump.

[0087] Step S630: Heat the target collection unit to vaporize the enriched target components and allow them to enter the sample collection tube;

[0088] Step S640: After the target components in the current target collection unit have been collected, replace the sample collection tube and re-determine the next target collection unit to be collected in the remaining target cold trap units.

[0089] Specifically, methane is first collected, with the methane-enriched four-stage cold trap 211 serving as the target collection unit. After the methane frozen in the four-stage cold trap 211 (liquid nitrogen, 77±10K) solidifies, the fourth three-way valve 213 and the sixth three-way valve 216 are placed in a connected and vacuumed state, meaning the vacuum pump 214 connects the four-stage cold trap 211 and the sample collection tube 217 simultaneously through the sixth three-way valve 216. The fourth two-way valve 212 is opened to evacuate the carrier gas (He) in the pipeline of the four-stage cold trap 211 (liquid nitrogen 77K). When the pipeline vacuum reaches equilibrium, the sixth three-way valve 216 is switched to maintain the connection between the four-stage cold trap 211 and the sample collection tube 217 while disconnecting from the vacuum pump 214.

[0090] At this point, place the liquid nitrogen cup at 1 / 2 of the sample collection tube 217, remove the liquid nitrogen cup from the fourth-stage cold trap 211, and place a glass cup containing room temperature water at 20-35℃ on top to heat the fourth-stage cold trap 211. At this time, the methane that has solidified and accumulated in the fourth-stage cold trap 211 will rapidly vaporize. Based on the principle of thermal expansion and contraction, the sublimated methane will be transferred into the sample collection tube 217. Seal the sample collection tube 217, remove it for later use, and replace it with a new sample collection tube 217.

[0091] Step S650: Repeat steps S610 to S640 to complete the collection of other components.

[0092] Specifically, after collecting methane, ethane and propane components are collected sequentially.

[0093] First, ethane is collected, with the ethane-enriched triple cold trap 208 as the target collection unit. After the ethane frozen in the triple cold trap 208 (liquid nitrogen, 77±10K) solidifies, the third three-way valve 210 and the sixth three-way valve 216 are placed in a connected and vacuumed state, that is, the vacuum pump 214 is simultaneously connected to the triple cold trap 208 and the sample collection tube 217 through the sixth three-way valve 216. The third two-way valve 209 is opened, connecting the vacuum pump 214 to the fourth three-way valve 213, the third three-way valve 210, and the sample collection tube 217, respectively, to evacuate the carrier gas (He) in the triple cold trap 208 pipeline. When the pipeline vacuum reaches equilibrium, the sixth three-way valve 216 is switched to maintain the connection between the triple cold trap 208 and the sample collection tube 217 while disconnecting from the vacuum pump 214.

[0094] At this point, place the liquid nitrogen cup at 1 / 2 of the sample collection tube 217, remove the freezing (liquid nitrogen, 77±10K) cup of the third-stage cold trap 208, and place a glass cup containing room temperature water at 20-35℃ on top to heat the third-stage cold trap 208. At this time, the solidified and enriched ethane in the third-stage cold trap 208 will rapidly vaporize. Based on the principle of thermal expansion and contraction, the vaporized ethane will transfer into the sample collection tube 217. Seal the sample collection tube 217, remove it for later use, and replace it with a new sample collection tube 217.

[0095] Then, propane is collected, with the propane-enriched secondary cold trap 205 as the target collection unit. After the propane frozen in the secondary cold trap 205 (liquid nitrogen, 77±10K) solidifies, the second three-way valve 207 and the sixth three-way valve 216 are placed in a connected and evacuated state, that is, the vacuum pump 214 is simultaneously connected to the secondary cold trap 205 and the sample collection tube 217 through the sixth three-way valve 216. The second two-way valve 206 is opened to evacuate the carrier gas (He) in the pipeline of the secondary cold trap 205. When the pipeline vacuum reaches equilibrium, the sixth three-way valve 216 is switched to maintain the connection between the secondary cold trap 205 and the sample collection tube 217 and disconnect the connection with the vacuum pump 214.

[0096] At this point, place the liquid nitrogen cup at 1 / 2 of the sample collection tube 217, remove the freezing (liquid nitrogen, 77±10K) cup from the secondary cold trap 205, and place a glass cup containing room temperature water at 20-35℃ on top to heat the secondary cold trap 205. At this time, the propane that has solidified and accumulated in the secondary cold trap 205 will rapidly vaporize. Based on the principle of thermal expansion and contraction, the vaporized propane will be transferred into the sample collection tube 217. Seal the sample collection tube 217, remove it for later use, and replace it with a new sample collection tube 217.

[0097] It should be noted that, depending on the required amount of sample, the above steps can be repeated multiple times to purify and enrich the target components in the natural gas.

[0098] Similarly, the above methods can also be used to collect other natural gas monomer components such as butane, pentane, and carbon dioxide, and can also be used to purify and enrich single natural gas components as needed for research.

[0099] In addition, please refer to the attached diagram. Figures 1 to 4 ,from Figure 2 As can be seen, for unpurified natural gas samples, methane, ethane, and propane components are present in FID gas chromatography. (This is achieved through...) Figure 4 After TCD gas chromatography separation, the purified gas collected after removing ethane and propane by switching four-way valve 105 was then analyzed by FID gas chromatography, revealing only the presence of methane, as shown in the attached figure. Figure 3 As shown, this demonstrates that a single natural gas component can be purified and collected through separation, with good purification and enrichment effects.

[0100] Example 3

[0101] The embodiments of the present invention provide a high-fidelity enrichment and separation system for natural gas monomer components, which includes the aforementioned separation device and a control device electrically connected to the separation device, thereby possessing all the technical effects it possesses.

[0102] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0103] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A natural gas single component high fidelity enrichment separation process characterized by, The application relates to a natural gas sample separation and collection method. The method comprises the following steps: inputting a natural gas sample into a chromatographic column of a separation assembly, performing chromatographic separation, and keeping the output end of the chromatographic column communicated with a venting pipeline; when a signal of a target component in the natural gas sample is detected at the output end of the chromatographic column, switching the output end of the chromatographic column to a conducting enrichment assembly, the enrichment assembly comprises a plurality of cold trap units connected in series, and each cold trap unit has a certain enrichment temperature, and the enrichment temperatures of the plurality of cold trap units gradually decrease along the flow direction of the natural gas sample in the enrichment assembly; making the target component sequentially pass through the cold trap units connected in series and having certain enrichment temperatures, and making the target component frozenly enriched in a target cold trap unit at the tail end of the plurality of cold trap units sequentially passed through; valve assemblies are arranged on the pipelines between two adjacent cold trap units and between the cold trap unit at the tail end of the enrichment assembly and a collection assembly, and the valve assemblies comprise two-way valves and three-way valves arranged in sequence along the flow direction of the natural gas sample; after the target component is enriched, the input end and the output end of the corresponding target cold trap unit are closed, and the pipeline in front of the input end of the target cold trap unit is switched to the venting pipeline; after all the target components are frozenly enriched, the corresponding target components are collected through a collection assembly according to the same sequence as the sequence of the enrichment of the target components, and the collection assembly comprises a sample collection pipeline connected to the output end of the cold trap unit at the tail end of the enrichment assembly.

2. The natural gas single component high fidelity enrichment separation process of claim 1, wherein, A vacuum pump is connected to the pipeline between the enrichment assembly and the collection assembly through a three-way valve, and the vacuum pump is provided with a vacuum pressure controller.

3. The natural gas single component high fidelity enrichment separation process of claim 1, wherein, A four-way valve is arranged between the separation assembly and the enrichment assembly, and four interfaces of the four-way valve are connected to the output end of the separation assembly, the input end of the enrichment assembly, a carrier gas bottle and the venting pipeline.

4. The natural gas single component high fidelity enriched separation process according to any one of claims 1 to 3, characterized in that, A three-way valve is arranged at the input end of the cold trap unit of the enrichment assembly directly connected to the chromatographic column.

5. The natural gas single component high fidelity enriched separation process according to any one of claims 1 to 3, characterized in that, A thermal conductivity detector is arranged at the output end of the chromatographic column.

6. The natural gas single component high fidelity enrichment separation process of claim 1, wherein, The corresponding target components are collected according to the same sequence as the sequence of the enrichment of the target components, and the method comprises the following steps: the target cold trap unit at the tail end of all the target cold trap units currently enriched with the target components is taken as a target collection unit, the output end of the target collection unit is switched to an open state and kept communicated with a sample collection pipeline arranged at the rear end of the enrichment assembly; the target collection unit is heated, the target component enriched in the target collection unit is vaporized and enters the sample collection pipeline; after the target component in the current target collection unit is collected, the sample collection pipeline is replaced, and the next target collection unit is determined again in the remaining target cold trap units.

7. The natural gas single component high fidelity enriched separation process of claim 6, wherein, Before the target collection unit is heated, the method further comprises the following steps: the vacuum pump arranged between the enrichment assembly and the sample collection pipeline is started, and the target collection unit and the sample collection pipeline are vacuumized. After the vacuuming is completed, the target collection unit is kept in communication with the sample collection tube and the vacuuming end of the vacuum pump is closed.

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