Soil gas collection device, soil gas collection method and soil gas field detection method

Abstract

The invention relates to an in-soil gas collection device, an in-soil gas collection method and an in-soil gas field detection method, relates to the technical field of geochemical exploration, and aims to solve the problems that in-soil gas samples collected by the in-soil gas collection device are low in fidelity and target components cannot be enriched. The soil gas collecting device comprises a gas collecting tank assembly, a gas collecting port and a gas outlet are formed in one end of the gas collecting tank assembly, and an opening is formed in the other end of the gas collecting tank assembly; the gas production port rubber plug is detachably arranged in the gas production port, and the gas production port rubber plug is used for blocking the gas production port; and the air outlet assembly communicates with the air outlet. According to the invention, air cannot be mixed into the gas collection tank assembly. Therefore, the soil gas sample taken out from the gas collection port does not contain air. Therefore, the fidelity of the soil gas sample is ensured. And the device is filled with the non-target component absorbent, and the non-target component absorbent is used for absorbing non-target components in the soil gas, so that the target components in the soil gas sample can be enriched.

Description

Technical Field

[0001] This invention relates to the field of geochemical exploration technology, and in particular to a soil gas collection device, a soil gas collection method, and a soil gas on-site detection method. Background Technology

[0002] If oil and gas reservoirs, carbon dioxide, hydrogen, and rare gases exist in the formation, these gas components will undergo vertical micro-transportation to the shallow surface soil due to differences in concentration, formation pressure, and temperature, leading to an increase in the concentration of the corresponding gas components in the soil. Measuring the gas components in soil gas can help track and predict oil and gas reservoirs, carbon dioxide, hydrogen, and rare gas reservoirs in the underlying strata. In recent years, with the increasing demand for energy and resources and growing emphasis on the environment, the sampling and detection of various components in soil gas has become increasingly important, such as light hydrocarbons like CH4, H2, H2S, He, Ne, and Rn. This information can provide important reference data for research on energy, resources, environment, and disasters.

[0003] In existing technologies, soil gas sampling methods typically employ conventional drilling tools. These methods introduce air contamination during sample collection, resulting in air-contaminated samples that compromise sample fidelity. Furthermore, the samples obtained using these methods often contain a high proportion of non-target components, preventing the enrichment of target components. This negatively impacts the accuracy of subsequent soil gas analysis, ultimately hindering the acquisition of truly reliable data.

[0004] In other words, existing soil gas collection devices suffer from low fidelity and the inability to enrich target components in the soil gas samples they collect. Summary of the Invention

[0005] This invention provides a soil gas collection device, a soil gas collection method, and a soil gas field detection method to solve the problems of low fidelity and inability to enrich target components in soil gas samples collected by the soil gas collection device.

[0006] This invention provides a soil gas collection device, comprising:

[0007] The gas collecting tank assembly has a gas intake port and a gas outlet at one end, and an opening at the other end.

[0008] A gas sampling port plug, which is detachably installed inside the gas sampling port, is used to seal the gas sampling port; and

[0009] An air outlet assembly, which is connected to an air outlet;

[0010] The gas collecting tank assembly is filled with a non-target component absorbent, and the gas outlet assembly is connected to an external vacuum device. When the gas collecting tank assembly is in a vacuum state, the soil gas is drawn into the gas collecting tank assembly through the opening, and the non-target components in the soil gas are absorbed by the non-target component absorbent. The target components in the soil gas are then taken out through the gas sampling port.

[0011] In one embodiment, the gas collection tank assembly includes:

[0012] A gas collecting tank has a gas intake port and a gas outlet at one end, and an opening at the other end.

[0013] A semi-permeable membrane is installed at the opening of the gas collecting tank;

[0014] The non-target component absorbent is filled in the gas collection tank and placed on a semi-permeable membrane. The soil gas passes through the semi-permeable membrane and the non-target component absorbent in sequence before being taken out from the gas collection port.

[0015] In one embodiment, the non-target component absorbent includes an H2O absorbent disposed on a semi-permeable membrane for absorbing moisture from the soil atmosphere.

[0016] In one embodiment, the non-target component absorbent further includes a gas absorbent disposed on the H2O absorbent, which is used to absorb non-target gases in the soil gas.

[0017] In one embodiment, the gas absorbent includes at least one of a CO2 absorbent, an N2 absorbent, and an O2 absorbent.

[0018] In one embodiment, the outlet assembly includes:

[0019] An exhaust pipe, one end of which is connected to an exhaust port, and the other end of which is connected to an external vacuum device; and

[0020] An outlet valve is installed on the outlet pipe and is used to open or close the outlet pipe.

[0021] When the external vacuum device evacuates the gas collection tank assembly, the other end of the gas outlet pipe is connected to the external vacuum device, the gas collection port is closed, and the gas outlet valve is open.

[0022] In one embodiment, after the external vacuuming device finishes evacuating the gas collecting tank assembly, the outlet valve is closed, the sampling port is open, and it is connected to the external sampling device.

[0023] In one embodiment, the system also includes a field analyzer for detecting and analyzing the methane content in the gas inside the gas collecting tank assembly. After the external vacuuming device finishes evacuating the gas collecting tank assembly, the gas sampling port is closed, the gas outlet valve is open, and the field analyzer is connected to the gas outlet pipe.

[0024] In one embodiment, an air inlet is provided at one end of the gas collecting tank assembly, and it further includes:

[0025] An air intake assembly that is connected to the air intake;

[0026] The field analyzer has its inlet and outlet components connected, and its outlet and inlet components connected.

[0027] The soil gas in the gas collection tank assembly can be circulated into the field analyzer through the inlet and outlet assemblies. The field analyzer is used to circulate and detect the methane content in the soil gas in the gas collection tank assembly.

[0028] In one embodiment, the air intake assembly includes:

[0029] An air intake pipe, one end of which connects to the air inlet, and the other end of which connects to the outlet of the field analyzer; and

[0030] An air inlet valve is installed on the air inlet pipe and is used to open or close the air inlet pipe.

[0031] When the external vacuum device evacuates the gas collection tank assembly, the inlet valve is closed; when the outlet of the field analyzer is connected to the other end of the inlet pipe, the inlet valve is open.

[0032] The present invention also provides a method for collecting soil gas, the method employing the above-mentioned soil gas collection device, comprising:

[0033] Step S10: Fill the soil gas collection device with non-target component absorbent;

[0034] Step S20: Carry the soil gas collection device to the predetermined sampling point;

[0035] Step S30: Drill holes at the sampling points;

[0036] Step S40: Place the soil gas collection device into the borehole;

[0037] Step S50: Seal the gap between the soil gas collection device and the borehole;

[0038] Step S60: Insert a gas sampling port rubber plug into the gas sampling port;

[0039] Step S70: Connect the air outlet assembly to the external vacuum device;

[0040] Step S80: Vacuum the gas collection tank assembly using an external vacuum pumping device.

[0041] Step S90: Shut down the air outlet assembly;

[0042] Step S100: After a preset time interval, remove the rubber plug from the gas sampling port and connect the gas sampling port to the external sampling device;

[0043] Step S110: Continuously extract a preset volume of gas sample from the gas sampling port using an external sampling device;

[0044] Step S120: Transfer the gas sample into the gas collecting bottle;

[0045] Step S130: Bring the gas collecting bottle back to the laboratory for instrument analysis.

[0046] The present invention also provides a method for on-site detection of soil gas, which uses the above-mentioned soil gas collection device and includes:

[0047] Step S10: Fill the soil gas collection device with non-target component absorbent;

[0048] Step S20: Carry the soil gas collection device to the predetermined sampling point;

[0049] Step S30: Drill holes at the sampling points;

[0050] Step S40: Place the soil gas collection device into the borehole;

[0051] Step S50: Seal the gap between the soil gas collection device and the borehole;

[0052] Step S60: Insert a gas sampling port rubber plug into the gas sampling port;

[0053] Step S70: Connect the air outlet assembly to the external vacuum device;

[0054] Step S80: Vacuum the gas collection tank assembly using an external vacuum pumping device.

[0055] Step S90: Shut down the air outlet assembly;

[0056] Step S100: After a preset time interval, connect the air outlet assembly to the inlet of the field analyzer.

[0057] Step S110: Open the air outlet assembly;

[0058] Step S120: The methane content in the soil gas is detected using a field analyzer.

[0059] The present invention also provides a method for on-site detection of soil gas, which uses the above-mentioned soil gas collection device and includes:

[0060] Step S10: Fill the soil gas collection device with non-target component absorbent;

[0061] Step S20: Carry the soil gas collection device to the predetermined sampling point;

[0062] Step S30: Drill holes at the sampling points;

[0063] Step S40: Place the soil gas collection device into the borehole;

[0064] Step S50: Seal the gap between the soil gas collection device and the borehole;

[0065] Step S60: Insert a gas sampling port rubber plug into the gas sampling port;

[0066] Step S70: Connect the air outlet assembly to the external vacuum device;

[0067] Step S80: Shut down the air intake assembly;

[0068] Step S90: Vacuum the gas collecting tank assembly using an external vacuum pumping device.

[0069] Step S100: Shut down the air outlet assembly;

[0070] Step S110: After a preset time interval, connect the air outlet assembly to the inlet of the field analyzer and connect the air inlet assembly to the outlet of the field analyzer.

[0071] Step S120: Open the air outlet assembly and the air inlet assembly;

[0072] Step S130: The methane content in the soil gas is cyclically detected using a field analyzer.

[0073] Compared with existing technologies, the advantages of this invention are that an external vacuum device removes air from the gas collection tank assembly, creating a vacuum and negative pressure within it. Under this negative pressure, soil gas at the corresponding burial depth can be drawn into the gas collection tank assembly through the opening. Throughout the entire extraction process, air cannot mix into the gas collection tank assembly. This ensures that the soil gas sample taken from the sampling port is air-free, thus avoiding interference from air and ensuring the fidelity of the soil gas sample. Furthermore, the soil gas collection device in this embodiment is filled with a non-target component absorbent. This absorbent removes non-target components from the soil gas, eliminating interference from non-target components such as H2O, CO2, N2, and O2. This allows the target component to be enriched in the soil gas sample, increasing its proportion and reducing detection errors, thus ensuring accurate and reliable data. Attached Figure Description

[0074] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0075] Figure 1 This is a schematic diagram of the structure of the soil gas collection device in Embodiment 1 of the present invention;

[0076] Figure 2 This is a schematic diagram of the structure of the soil gas collection device in Embodiment 2 of the present invention;

[0077] Figure 3 This is a schematic diagram of the structure of the soil gas collection device in Embodiment 3 of the present invention;

[0078] Figure 4 This is a flowchart of the soil gas collection method in Embodiment 4 of the present invention;

[0079] Figure 5 This is a flowchart of the soil gas field detection method in Embodiment 5 of the present invention;

[0080] Figure 6 This is a flowchart of the soil gas field detection method in Embodiment Six of the present invention.

[0081] Figure label:

[0082] 10. Gas collection tank assembly; 11. Gas collection tank; 111. Gas sampling port; 112. Gas outlet; 113. Gas inlet; 12. Non-target component absorbent; 121. H2O absorbent; 122. Gas absorbent; 1221. CO2 absorbent; 1222. N2 absorbent; 1223. O2 absorbent; 13. Semi-permeable membrane; 30. Gas outlet assembly; 31. Gas outlet pipe; 32. Gas outlet valve; 40. On-site analyzer; 50. Gas inlet assembly; 51. Gas inlet pipe; 52. Gas inlet valve; 60. Gas sampling port rubber plug; 100. External vacuum device. Detailed Implementation

[0083] The invention will now be further described with reference to the accompanying drawings.

[0084] Example 1

[0085] like Figure 1 As shown, the present invention provides a soil gas collection device, which includes a gas collection tank assembly 10, a gas sampling port stopper 20, and a gas outlet assembly 30. The gas collection tank assembly 10 has a gas sampling port 111 and a gas outlet 112 at one end, and an opening at the other end. The gas sampling port stopper 20 is detachably installed inside the gas sampling port 111 and is used to seal the gas sampling port 111. The gas outlet assembly 30 is connected to the gas outlet 112. The gas collection tank assembly 10 is filled with a non-target component absorbent 12. The gas outlet assembly 30 is connected to an external vacuum device 100. When the gas collection tank assembly 10 is under vacuum, soil gas is drawn into the gas collection tank assembly 10 through the opening, and the non-target components in the soil gas are absorbed by the non-target component absorbent 12. The soil gas sample is then taken out through the gas sampling port 111.

[0086] In the above setup, an external vacuum device 100 evacuates the air from the gas collection tank assembly 10, creating a vacuum and negative pressure within it. Under this negative pressure, the soil gas at the corresponding burial depth is drawn into the gas collection tank assembly 10 through the opening. Throughout the entire extraction process, air cannot mix into the gas collection tank assembly 10. This ensures that the soil gas sample taken from the gas sampling port 111 is air-free, thus avoiding interference from air and ensuring the fidelity of the soil gas sample. Furthermore, the soil gas collection device in this embodiment is filled with a non-target component absorbent 12. This absorbent absorbs non-target components from the soil gas, eliminating interference from non-target components such as H2O, CO2, N2, and O2. This allows the target components in the soil gas sample to be enriched, increasing the proportion of target components and reducing detection errors, thus ensuring accurate and valid data.

[0087] Specifically, such as Figure 1As shown, in one embodiment, the gas collection tank assembly 10 includes a gas collection tank 11 and a semi-permeable membrane 13. The gas collection tank 11 has a gas intake port 111 and a gas outlet 112 at one end, and an opening at the other end. The semi-permeable membrane 13 is disposed at the opening of the gas collection tank 11. A non-target component absorbent 12 is filled inside the gas collection tank 11 and disposed on the semi-permeable membrane 13. Soil gas passes sequentially through the semi-permeable membrane 13 and the non-target component absorbent 12 before being extracted from the gas intake port 111.

[0088] Specifically, such as Figure 1 As shown, in one embodiment, the tank material of the gas collection tank 11 can be glass, plexiglass, stainless steel, etc. The tank diameter and tank length can be processed according to the sampling depth and sampling volume. The middle and lower ends of the tank can be an integral structure or can be composed of multiple segmented tubes. The bottom of the tank is lined with a semi-permeable membrane 13.

[0089] Specifically, in one embodiment, the semipermeable membrane 13 can be made of materials such as polyamide membrane or cellulose acetate membrane, allowing gas to pass through unimpeded and water to pass through slowly. The semipermeable membrane 13 can be fixed in position using materials such as stainless steel mesh.

[0090] Specifically, such as Figure 1 As shown, in one embodiment, the vent assembly 30 is sealed to the gas collection tank 11.

[0091] Specifically, such as Figure 1 As shown, in one embodiment, the non-target component absorbent 12 includes an H2O absorbent 121 disposed on a semi-permeable membrane 13 for absorbing moisture in the soil atmosphere.

[0092] In the above setup, H2O absorbent 121 is used to absorb moisture from the soil atmosphere. This reduces the dead volume of the device, thereby eliminating moisture interference, increasing the content of the target component, reducing the detection error of the target component, and ultimately ensuring accurate acquisition of the target component, thus providing a guarantee for obtaining accurate and effective data.

[0093] Specifically, in one embodiment, the H2O absorbent 121 may be a desiccant such as silica gel, calcium chloride, or calcium sulfate.

[0094] Specifically, such as Figure 1 As shown, in one embodiment, the non-target component absorbent 12 further includes a gas absorbent 122 disposed on the H2O absorbent 121, the gas absorbent 122 being used to absorb non-target gases in the soil gas.

[0095] In the above setup, a gas absorbent 122 is used to absorb non-target gas components in the soil gas. This reduces the dead volume of the device, thereby eliminating interference from non-target gas components, increasing the content of the target component, and reducing the detection error of the target component.

[0096] Specifically, such as Figure 1 As shown, in one embodiment, the gas absorbent 122 includes a CO2 absorbent 1221, an N2 absorbent 1222, and an O2 absorbent 1223.

[0097] Specifically, such as Figure 1 As shown, in one embodiment, CO2 absorbent 1221 is disposed on H2O absorbent 121, O2 absorbent 1223 is disposed on CO2 absorbent 1221, and N2 absorbent 1222 is disposed on O2 absorbent 1223.

[0098] It should be noted that the H2O absorbent 121 is positioned below the gas absorbent 122. This is to prevent moisture from reacting with the upper gas absorbent or forming a water film on the absorbent surface, which would affect the absorption efficiency.

[0099] It should be noted that CO2 absorbent 1221 can be made of calcium hydroxide, soda lime, barium lime, etc., N2 absorbent 1222 can be made of barium carbonate, barium phosphate, barium borate, etc., and O2 absorbent 1223 can be made of iron powder, ascorbic acid, etc.

[0100] It should be noted that gas absorbent 122 is not limited to including only CO2 absorbent 1221, N2 absorbent 1222, and O2 absorbent 1223, but may also include other gas absorbents. Gas absorbent 122 may also include at least one of CO2 absorbent 1221, N2 absorbent 1222, and O2 absorbent 1223. Different gas absorbents are used to absorb corresponding gases in the soil gas, thereby reducing interference from non-target gas components in the soil gas. This increases the content of the target component and reduces the detection error of the target component. If CO2, N2, and O2 are the target detection components, then CO2, N2, and O2 absorbents are not used.

[0101] Specifically, such as Figure 1 As shown, in one embodiment, the vent assembly 30 includes a vent pipe 31 and a vent valve 32. One end of the vent pipe 31 is connected to the vent 112, and the other end is connected to an external vacuum device 100. The vent valve 32 is mounted on the vent pipe 31 and is used to open or close the vent pipe 31. When the external vacuum device 100 evacuates the gas collecting tank assembly 10, the other end of the vent pipe 31 is connected to the external vacuum device 100, the gas collecting port 111 is closed, and the vent valve 32 is open.

[0102] Specifically, such as Figure 1 As shown, in one embodiment, after the external vacuum device 100 finishes evacuating the gas collection tank assembly 10, the outlet valve 32 is closed, the gas sampling port 111 is open, and it is connected to the external sampling device. This allows the external sampling device to extract a soil gas sample, free from interference from non-target components, at the gas sampling port 111.

[0103] Example 2

[0104] This invention provides a soil gas collection device, which differs from the above-described embodiment 1 in the following ways:

[0105] Specifically, such as Figure 2 As shown, in one embodiment, the soil gas collection device further includes a field analyzer 40, which is used to detect and analyze the methane content in the soil gas within the gas collection tank assembly 10. Specifically, after the external vacuum device 100 completes the vacuuming of the gas collection tank assembly 10, the gas sampling port 111 is closed, the gas outlet valve 32 is open, and the field analyzer 40 is connected to the gas outlet pipe 31. The field analyzer 40 can detect and analyze the soil gas output from the gas outlet pipe 31.

[0106] It should be noted that the on-site analyzer 40 can be equipped with appropriate detection instruments, such as portable chromatographs, sensors, and greenhouse gas infrared detectors, depending on the target component being detected. The connection between the on-site analyzer 40 and the gas outlet pipe 31 can be made using rubber tubing, plastic tubing, etc.

[0107] The other structures in Example 2 are the same as those in Example 1, and will not be described again here.

[0108] Example 3

[0109] This invention provides a soil gas collection device, which differs from the above-described embodiment 1 in the following ways:

[0110] Specifically, such as Figure 3 As shown, in one embodiment, an air inlet 113 is provided at one end of the gas collection tank assembly 10, and it also includes an air inlet assembly 50 and a field analyzer 40. The air inlet assembly 50 is connected to the air inlet 113; the inlet of the field analyzer 40 is connected to the outlet assembly 30, and the outlet of the field analyzer 40 is connected to the air inlet assembly 50. The soil gas in the gas collection tank assembly 10 can be circulated into the field analyzer 40 through the air inlet assembly 50 and the outlet assembly 30. The field analyzer 40 is used to circulate and detect and analyze the methane content in the soil gas in the gas collection tank assembly 10.

[0111] It should be noted that the on-site analyzer 40 can be equipped with appropriate detection instruments, such as portable chromatographs, sensors, and greenhouse gas infrared detectors, depending on the target component being detected. The connection between the on-site analyzer 40 and the gas outlet pipe 31 can be made using rubber tubing, plastic tubing, etc.

[0112] Specifically, such as Figure 3 As shown, in one embodiment, the air inlet assembly 50 includes an air inlet pipe 51 and an air inlet valve 52. One end of the air inlet pipe 51 is connected to the air inlet 113, and the other end of the air inlet pipe 51 is connected to the outlet of the field analyzer 40. The air inlet valve 52 is disposed on the air inlet pipe 51 and is used to open or close the air inlet pipe 51. When the external vacuum device 100 evacuates the gas collection tank assembly 10, the air inlet valve 52 is in a closed state; when the outlet of the field analyzer 40 is connected to the other end of the air inlet pipe 51, the air inlet valve 52 is in an open state.

[0113] The other structures in Example 3 are the same as those in Example 1, and will not be described again here.

[0114] Example 4

[0115] like Figure 4 As shown, the present invention also provides a method for collecting soil gas, which uses the soil gas collection device in Embodiment 1 above, and includes the following steps:

[0116] Step S10: Fill the soil gas collection device with non-target component absorbent;

[0117] Step S20: Carry the soil gas collection device to the predetermined sampling point;

[0118] Step S30: Drill holes at the sampling points;

[0119] Step S40: Place the soil gas collection device into the borehole;

[0120] Step S50: Seal the gap between the soil gas collection device and the borehole;

[0121] Step S60: Insert a gas sampling port rubber plug into the gas sampling port;

[0122] Step S70: Connect the air outlet assembly to the external vacuum device;

[0123] Step S80: Vacuum the gas collection tank assembly using an external vacuum pumping device.

[0124] Step S90: Shut down the air outlet assembly;

[0125] Step S100: After a preset time interval, remove the rubber plug from the gas sampling port and connect the gas sampling port to the external sampling device;

[0126] Step S110: Continuously extract a preset volume of gas sample from the gas sampling port using an external sampling device;

[0127] Step S120: Transfer the gas sample into the gas collecting bottle;

[0128] Step S130: Bring the gas collecting bottle back to the laboratory for instrument analysis.

[0129] According to the above steps, the air inside the gas collecting tank assembly 10 is evacuated by an external vacuum device, creating a vacuum and negative pressure inside the assembly. Under this negative pressure, the soil gas at the corresponding burial depth is drawn into the gas collecting tank assembly 10 through the opening, where non-target components are absorbed by the non-target component absorbent 12. This ensures that the target components in the soil gas can be extracted from the gas sampling port 111. This allows for targeted and precise sampling of soil gas, reducing air interference. By filling the device with the non-target component absorbent 12, the dead volume of the device is reduced, and interference from non-target components such as H2O, CO2, N2, and O2 is eliminated, thereby enriching the target components, increasing their content, reducing detection errors, and accurately obtaining the target components, ensuring accurate and effective data. Furthermore, the external sampling device can extract a preset volume of gas sample from the gas sampling port, enabling large-volume sampling of soil gas.

[0130] Specifically, in one embodiment, the soil gas collection method includes:

[0131] After filling the device with H2O absorbent (calcium sulfate), CO2 (calcium hydroxide), N2 absorbent (barium carbonate), and O2 absorbent (iron powder), carry the device to the predetermined sampling point A. Drill a hole with tools (twist drill, Luoyang shovel), the hole diameter slightly larger than the tank diameter and the depth 1.2m. Place the device, with a tank diameter of 6cm and a length of 1.3m, into the drilled hole, compact and seal the perimeter with soil, and seal the gas sampling port with a rubber stopper. Close the inlet valve and open the outlet valve. Connect the atmospheric sampler extraction device (external vacuum device) to the outlet end, close the outlet valve, and remove the atmospheric sampler extraction device. Because the device is under negative pressure, soil interstitial gas (soil gas) will be drawn into the device. After equilibration for 24 hours, continuously extract 200mL of gas sample from the sampling port using a syringe, transfer it to a gas collection bottle, and bring it back to the laboratory for instrument analysis. In the laboratory, light hydrocarbons in the samples were determined using a gas chromatograph with a flame hydrogen detector, and the contents of He, Ne, and H2 were determined using a gas chromatograph with a thermal conductivity detector. The results are shown in Table 1.

[0132] Table 1. Gas component content in soil at sample point A (μL / L)

[0133] Sample number <![CDATA[CH4]]> <![CDATA[C2H6]]> <![CDATA[C2H4]]> <![CDATA[C3H8]]> <![CDATA[C3H6]]> <![CDATA[i-C4H 10 ]]> <![CDATA[n-C4H 10 ]]> <![CDATA[i-C5H 12 ]]> <![CDATA[n-C5H 12 ]]> He Ne <![CDATA[H2]]> A 20.46 2.75 0.30 1.18 0.34 0.40 0.63 0.36 0.32 6.67 19.28 1103.31

[0134] Comparative Example

[0135] As mentioned in the background section of this invention, Chinese patent CN101236141A discloses a soil gas sampling auger, which, like this invention, belongs to the category of soil gas sampling devices. This soil gas sampling auger includes components such as a conical drill bit body, a capped auger rod, a drill rod, and a handle, and is a manual soil gas sampling device. To illustrate the accuracy and effectiveness of the high-fidelity gas collection device and method of this invention, this soil gas sampling auger is used as a comparative example for comparison and explanation.

[0136] Specifically, the ground-gas sampling auger disclosed in CN101236141A was used to collect gas samples at the same depth and location 20 cm away from the sampling point in Example 1 above, with a maximum sampling volume of 8.5 mL. The light hydrocarbon content and helium-neon hydrogen content in the samples collected at the sampling point were determined using the same gas chromatograph with a flame ionization detector and a thermal conductivity detector as in Example 1 above, and the results are shown in Table 2.

[0137] Table 2. Soil gas component content (μL / L) collected by the soil gas sampling auger at sampling point A.

[0138] Sample number <![CDATA[CH4]]> <![CDATA[C2H6]]> <![CDATA[C2H4]]> <![CDATA[C3H8]]> <![CDATA[C3H6]]> <![CDATA[i-C4H 10 ]]> <![CDATA[n-C4H 10 ]]> <![CDATA[i-C5H 12 ]]> <![CDATA[n-C5H 12 ]]> He Ne <![CDATA[H2]]> A 11.15 0.76 0.23 0.29 0.26 0.10 0.18 0.13 0.16 5.24 14.02 961.39

[0139] By comparing Table 1 of Example 4 with Table 2 of the comparative example, it can be seen that the content of target components in the soil gas samples collected using the device of the present invention is higher than that of gas samples collected by the existing land gas sampling auger. Meanwhile, the maximum collectable volume of gas samples collected by the land gas sampling auger at point A is 8.5 mL, which is significantly less than the amount of gas samples that can be collected using the present invention. Therefore, the device of the present invention can obtain a larger amount of gas samples with higher content of target components.

[0140] Example 5

[0141] like Figure 5 As shown, the present invention also provides a field detection method, which uses the soil gas collection device in Embodiment 2 above, and includes the following steps:

[0142] Step S10: Fill the soil gas collection device with non-target component absorbent;

[0143] Step S20: Carry the soil gas collection device to the predetermined sampling point;

[0144] Step S30: Drill holes at the sampling points;

[0145] Step S40: Place the soil gas collection device into the borehole;

[0146] Step S50: Seal the gap between the soil gas collection device and the borehole;

[0147] Step S60: Insert a gas sampling port rubber plug into the gas sampling port;

[0148] Step S70: Connect the air outlet assembly to the external vacuum device;

[0149] Step S80: Vacuum the gas collection tank assembly using an external vacuum pumping device.

[0150] Step S90: Shut down the air outlet assembly;

[0151] Step S100: After a preset time interval, connect the air outlet assembly to the inlet of the field analyzer.

[0152] Step S110: Open the air outlet assembly;

[0153] Step S120: The methane content in the soil gas is detected using a field analyzer.

[0154] According to the above steps, an external vacuum device evacuates the air from the gas collecting tank assembly 10, creating a vacuum and negative pressure inside. Under this negative pressure, the soil gas at the corresponding burial depth is drawn into the gas collecting tank assembly 10 through the opening, where non-target components are absorbed by the non-target component absorbent 12. This ensures that the target components in the soil gas can be extracted from the gas sampling port 111. This allows for the collection of soil gas samples at a fixed point and depth, reducing air interference. By filling the device with the non-target component absorbent 12, the dead volume of the device is reduced, and interference from non-target components such as H2O, CO2, N2, and O2 is eliminated, thereby enriching the target components, increasing their content, reducing detection errors, and accurately obtaining the target components, ensuring accurate and effective data. Furthermore, the gas outlet assembly is connected to the inlet of the on-site analyzer, enabling online detection and analysis of the soil gas.

[0155] Specifically, in one embodiment, the on-site detection method includes:

[0156] After filling the device with H2O absorbent (calcium sulfate), CO2 (calcium hydroxide), N2 absorbent (barium carbonate), and O2 absorbent (iron powder), transport the device to the predetermined sampling point C. Drill a hole using tools (twist drill, Luoyang shovel), with the hole diameter slightly larger than the tank diameter and a depth of 1.2m. Place the device (6cm diameter, 1.3m length) into the drilled hole, and seal the perimeter with soil. Seal the gas sampling port with a rubber stopper. Remove the on-site analyzer interface at the gas outlet end and close the gas inlet valve. Open the outlet valve, connect the atmospheric sampler extraction device (external vacuum device), close the outlet valve, remove the interface of the atmospheric sampler extraction device (used to connect the external vacuum device), and connect the on-site analyzer interface (used to connect the on-site analyzer) at the outlet end. Because the device is under negative pressure, soil interstitial gas (soil gas) will be drawn into the device. After equilibration for 24 hours, connect the G2301 gas analyzer, open the outlet valve, and let the gas pass through the on-site analyzer to determine the methane content before venting. The test results are shown in Table 3 below.

[0157] Table 3. Methane content in soil at sample point C (μL / L)

[0158] Sample number <![CDATA[CH4]]> C 4.314

[0159] Example 6

[0160] like Figure 6 As shown, the present invention also provides a field detection method, which uses the soil gas collection device in Embodiment 3 above, and includes the following steps:

[0161] Step S10: Fill the soil gas collection device with non-target component absorbent;

[0162] Step S20: Carry the soil gas collection device to the predetermined sampling point;

[0163] Step S30: Drill holes at the sampling points;

[0164] Step S40: Place the soil gas collection device into the borehole;

[0165] Step S50: Seal the gap between the soil gas collection device and the borehole;

[0166] Step S60: Insert a gas sampling port rubber plug into the gas sampling port;

[0167] Step S70: Connect the air outlet assembly to the external vacuum device;

[0168] Step S80: Shut down the air intake assembly;

[0169] Step S90: Vacuum the gas collecting tank assembly using an external vacuum pumping device.

[0170] Step S100: Shut down the air outlet assembly;

[0171] Step S110: After a preset time interval, connect the air outlet assembly to the inlet of the field analyzer and connect the air inlet assembly to the outlet of the field analyzer.

[0172] Step S120: Open the air outlet assembly and the air inlet assembly;

[0173] Step S130: The methane content in the soil gas is cyclically detected using a field analyzer.

[0174] According to the above steps, the air inside the gas collecting tank assembly 10 is evacuated by an external vacuum device, creating a vacuum and negative pressure inside the assembly. Under this negative pressure, the soil gas at the corresponding burial depth is drawn into the gas collecting tank assembly 10 through the opening, where non-target components are absorbed by the non-target component absorbent 12. This ensures that the target components in the soil gas can be extracted from the gas sampling port 111. This allows for the collection of soil gas samples at a fixed point and depth, reducing air interference. By filling the device with the non-target component absorbent 12, the dead volume of the device is reduced, and interference from non-target components such as H2O, CO2, N2, and O2 is eliminated, thereby enriching the target components, increasing their content, reducing detection errors, and accurately obtaining the target components, thus ensuring the acquisition of accurate and effective data. Furthermore, both the outlet and inlet assemblies are connected to the inlet of the on-site analyzer, enabling online circulation detection and analysis of the soil gas.

[0175] Specifically, in one embodiment, the on-site detection method includes: after filling the device with H2O absorbent (calcium sulfate), CO2 (calcium hydroxide), N2 absorbent (barium carbonate), and O2 absorbent (iron powder), the device is carried to the predetermined sampling point B. A hole is drilled using tools (twist drill, Luoyang shovel), with the hole diameter slightly larger than the tank diameter and a depth of 1.2m. The device, with a tank diameter of 6cm and a length of 1.3m, is placed into the drilled hole, and the perimeter is sealed with soil. The gas sampling port is then sealed with a rubber stopper. The on-site analyzer interface (used to connect the on-site analyzer) is removed from the gas outlet end. Close the inlet valve, open the outlet valve, connect the atmospheric sampler extraction device (external vacuum device), close the outlet valve, remove the interface of the atmospheric sampler (this interface is used to connect the external vacuum device), connect the on-site analyzer interface at the outlet end (this interface is used to connect the on-site analyzer), because the device is under negative pressure, the interstitial gas in the soil will be drawn into the device; after equilibration for 24 hours, connect the G2301 gas analyzer, open the inlet valve and outlet valve, and perform on-site internal gas circulation measurement to continuously, dynamically, and in real time monitor the methane content. The test results are shown in Table 4.

[0176] Table 4B shows the methane content (μL / L) in the soil from continuous monitoring.

[0177] Detection time <![CDATA[CH4]]> 10:15:00 3.177 10:16:00 3.174 10:17:00 3.189 10:18:00 3.156 10:19:00 3.165 10:20:00 3.141 10:21:00 3.179 10:22:00 3.168 10:23:00 3.193 10:24:00 3.194 10:25:00 3.156

[0178] It should be noted that the soil gas collection device in this invention uses a vacuum pump or atmospheric sampler extraction device (external vacuum device) to expel air, creating negative pressure, and then uses this negative pressure to draw in soil gas samples at the corresponding burial depth. This device can obtain soil gas samples at a fixed point and depth, reducing air interference. By filling the device with H2O absorbent, CO2 absorbent, N2 absorbent, and O2 absorbent, the dead volume of the device is reduced, and interference from non-target components such as H2O, CO2, N2, and O2 can be eliminated, increasing the content of the target components. Large-volume sampling can be performed and brought back to the laboratory for target component analysis, or continuous, dynamic, and real-time on-site detection or monitoring can be conducted. This ensures the collection of soil gas samples, reduces errors, accurately obtains the target components, and provides a guarantee for obtaining accurate and effective data.

[0179] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A soil gas collection device, characterized in that, include: A gas collecting tank assembly, one end of which is provided with a gas intake port and a gas outlet, and the other end of the gas collecting tank assembly is provided with an opening; A gas sampling port rubber plug is detachably disposed inside the gas sampling port, and the gas sampling port rubber plug is used to seal the gas sampling port; as well as An air outlet assembly, which is connected to the air outlet; The gas collecting tank assembly is filled with a non-target component absorbent. The gas outlet assembly is connected to an external vacuum device. When the gas collecting tank assembly is in a vacuum state, the soil gas is drawn into the gas collecting tank assembly through the opening. The non-target components in the soil gas are absorbed by the non-target component absorbent, and the target components in the soil gas are taken out through the gas sampling port.

2. The soil gas collection device according to claim 1, characterized in that, The gas collection tank assembly includes: A gas collecting tank, one end of which is provided with the gas intake port and the gas outlet, and the other end of which is provided with the opening; A semi-permeable membrane is disposed at the opening of the gas collecting tank; The non-target component absorbent is filled in the gas collection tank and placed on the semi-permeable membrane. The soil gas passes through the semi-permeable membrane and the non-target component absorbent in sequence and is then taken out from the gas collection port.

3. The soil gas collection device according to claim 2, characterized in that, The non-target component absorbent includes an H2O absorbent, which is disposed on the semi-permeable membrane for absorbing moisture from the soil atmosphere.

4. The soil gas collection device according to claim 3, characterized in that, The non-target component absorbent also includes a gas absorbent disposed on the H2O absorbent, which is used to absorb non-target gases in the soil gas.

5. The soil gas collection device according to claim 4, characterized in that, The gas absorbent includes at least one of CO2 absorbent, N2 absorbent, and O2 absorbent.

6. The soil gas collection device according to any one of claims 1 to 5, characterized in that, The air outlet assembly includes: An exhaust pipe, one end of which is connected to the exhaust port, and the other end of which is connected to the external vacuum device; and An outlet valve is provided on the outlet pipe, and the outlet valve is used to open or close the outlet pipe; When the external vacuum device evacuates the gas collecting tank assembly, the other end of the gas outlet pipe is connected to the external vacuum device, the gas sampling port is closed, and the gas outlet valve is open.

7. The soil gas collection device according to claim 6, characterized in that, After the external vacuuming device finishes evacuating the gas collecting tank assembly, the outlet valve is closed, the sampling port is open, and it is connected to the external sampling device.

8. The soil gas collection device according to claim 6, characterized in that, It also includes a field analyzer, which is used to detect and analyze the methane content in the soil gas inside the gas collection tank assembly. After the external vacuuming device finishes evacuating the gas collection tank assembly, the gas sampling port is closed, the gas outlet valve is open, and the field analyzer is connected to the gas outlet pipe.

9. The soil gas collection device according to claim 6, characterized in that, The gas collecting tank assembly has an air inlet at one end and also includes: An air inlet assembly, which is connected to the air inlet; The field analyzer has its inlet connected to the air outlet assembly, and its outlet connected to the air inlet assembly. The soil gas in the gas collection tank assembly can be circulated into the field analyzer through the air inlet assembly and the air outlet assembly. The field analyzer is used to circulate and detect and analyze the methane content in the soil gas in the gas collection tank assembly.

10. The soil gas collection device according to claim 9, characterized in that, The air inlet assembly includes: An air intake pipe, one end of which is connected to the air inlet, and the other end of which is connected to the outlet of the field analyzer; and An air inlet valve is provided on the air inlet pipe, and the air inlet valve is used to open or close the air inlet pipe; Specifically, when the external vacuum device evacuates the gas collection tank assembly, the air inlet valve is in a closed state; when the outlet of the field analyzer is connected to the other end of the air inlet pipe, the air inlet valve is in an open state.

11. A method for collecting soil gas, characterized in that, The soil gas collection method employs the soil gas collection device as described in any one of claims 1 to 10, which includes: Step S10: Fill the soil gas collection device with a non-target component absorbent; Step S20: Carry the soil gas collection device to the predetermined sampling point; Step S30: Drill holes at the sampling points; Step S40: Place the soil gas collection device into the borehole; Step S50: Seal the gap between the soil gas collection device and the borehole; Step S60: Insert the gas sampling port rubber plug into the gas sampling port; Step S70: Connect the air outlet assembly to the external vacuum device; Step S80: Vacuum the gas collecting tank assembly using the external vacuum pumping device; Step S90: Shut down the air outlet assembly; Step S100: After a preset time interval, remove the rubber plug from the gas sampling port and connect the gas sampling port to the external sampling device; Step S110: Continuously extract a preset volume of gas sample from the gas sampling port using the external sampling device; Step S120: Transfer the gas sample into a gas collecting bottle; Step S130: Bring the gas collecting bottle back to the laboratory for instrument analysis.

12. A method for on-site detection of soil gas, characterized in that, The soil gas field detection method uses the soil gas collection device described in claim 8, which includes: Step S10: Fill the soil gas collection device with a non-target component absorbent; Step S20: Carry the soil gas collection device to the predetermined sampling point; Step S30: Drill holes at the sampling points; Step S40: Place the soil gas collection device into the borehole; Step S50: Seal the gap between the soil gas collection device and the borehole; Step S60: Insert the gas sampling port rubber plug into the gas sampling port; Step S70: Connect the air outlet assembly to the external vacuum device; Step S80: Vacuum the gas collecting tank assembly using the external vacuum pumping device; Step S90: Shut down the air outlet assembly; Step S100: After a preset time interval, connect the air outlet assembly to the inlet of the field analyzer; Step S110: Open the air outlet assembly; Step S120: The methane content in the soil gas is detected using the field analyzer.

13. A method for on-site detection of soil gas, characterized in that, The soil gas field detection method uses the soil gas collection device described in claim 9, which includes: Step S10: Fill the soil gas collection device with a non-target component absorbent; Step S20: Carry the soil gas collection device to the predetermined sampling point; Step S30: Drill holes at the sampling points; Step S40: Place the soil gas collection device into the borehole; Step S50: Seal the gap between the soil gas collection device and the borehole; Step S60: Insert the gas sampling port rubber plug into the gas sampling port; Step S70: Connect the air outlet assembly to the external vacuum device; Step S80: Shut down the air intake assembly; Step S90: Vacuum the gas collecting tank assembly using the external vacuum pumping device; Step S100: Turn off the air outlet assembly; Step S110: After a preset time interval, connect the air outlet assembly to the inlet of the field analyzer and connect the air inlet assembly to the outlet of the field analyzer. Step S120: Open the air outlet assembly and the air inlet assembly; Step S130: The methane content in the soil gas is cyclically detected using the field analyzer.

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