Soil headspace gas collection device and method and soil gas detection system

Abstract

The invention relates to the technical field of soil gas collection, and discloses a soil headspace gas collection device and method and a soil gas detection system. A sample loading bottle opening is connected with a sample loading bottle cap in a sealing manner; the water injection bottleneck is formed in the first side surface of the container; the water injection bottle opening is hermetically connected with a needling water injection bottle cap; the air exhaust bottle opening is formed in the second side face of the container. And the air exhaust bottle opening is hermetically connected with the needling air exhaust bottle cap. The soil headspace collection method comprises the following steps: loading a saturated saline solution and a sample into a container; standing the container until gas in a gas state and a liquid state in the container reaches dynamic balance; placing the container in a first state, and standing the container until solid-liquid-gas three phases are separated; when the first injector injects water, the second injector extracts air from the container to collect soil gas. According to the technical scheme, time and labor can be saved, and the soil gas which is free and weakly adsorbed on the surfaces of the soil microparticles can be efficiently obtained. Furthermore, oil and gas reservoirs and gas reservoirs in the underlying stratum can be effectively tracked and predicted.

Description

Technical Field

[0001] The present invention relates to the technical field of soil gas collection, and particularly to a soil headspace gas collection device, a method and a soil gas detection system. Background Art

[0002] In the deep strata, for oil and gas reservoirs and gas reservoirs, due to factors such as material concentration difference, formation pressure difference, and formation temperature difference, the gas components will vertically migrate microscopically to the near-surface soil. Because the soil has a porous structure, these components exist in a free state between soil microparticles or are weakly adsorbed on the surface of soil microparticles in a weakly adsorbed state, resulting in an increase in the concentration of the corresponding gas components in the soil. Measuring these gas components can track and predict the oil and gas reservoirs and gas reservoirs in the underlying strata. Secondly, pesticides used in farmland and toxic and harmful gas substances from chemical plants leak into the soil underground with liquids and exist in a free state and in a weakly adsorbed form on the surface of soil microparticles. Effectively collecting these harmful gases that are free and weakly adsorbed on soil microparticles is very important for detecting and identifying soil pollution.

[0003] In the prior art, the method for collecting soil headspace gas (such as interstitial gas in farmland soil in environmental protection) in geochemical exploration technology is mainly to place the sample in a closed system such as a headspace bottle at a certain temperature (a headspace for the analytical diffusion collection of interstitial gas is reserved at the top of the headspace bottle), so that the light components that are free and weakly adsorbed and exist between soil microparticles in the soil sample can be volatilized as much as possible; after shaking and standing for a period of time, when the gas-liquid in the container reaches dynamic equilibrium, the gas phase component above the liquid surface is taken for measurement. At present, soil headspace bottles generally use 250 ml medical glass bottles for soil collection. The disadvantages of using this container to collect interstitial gas in soil are as follows: the sample collection glass bottle is fragile; it needs to be shaken (and may need to be heated and other steps during environmental protection detection) and then inverted before indoor analysis, so that the free and adsorbed components in the soil gas can be analyzed and diffused to reach gas-liquid dynamic equilibrium; during this process, the soil is easily consolidated at the rubber bottle stopper at the bottle mouth. When measuring the headspace gas, the container must be vibrated and placed upright for a period of time to make the soil solids precipitate to the bottom of the bottle and the gas be above the glass bottle to reach a new gas-liquid dynamic equilibrium, which is convenient for injecting water and pumping gas into the headspace of the container. There are two inconveniences in this process. One is that the sample bottle needs to be vibrated to shake the soil solids near the bottle mouth to precipitate to the bottom of the bottle. If it is clay soil, the soil is more firmly cemented at the bottle mouth, and this vibration process is laborious, time-consuming, and affects the detection efficiency; on the other hand, after the rubber bottle stopper blocking the bottle mouth contacts the soil microparticles, when the water injection needle and the gas extraction needle are inserted into the rubber bottle mouth, they are easily blocked by the soil microparticles, resulting in the inability to effectively complete the water injection and gas extraction work; during the vibration (heating) process of the container, the gas pressure in the container may be too high, causing the bottle stopper to pop out or the gas in the container to be lost.

[0004] How to design a soil gas sampling device that saves time, effort, and is highly efficient, and is not easily blocked by the injection needle, thereby avoiding the influence of unreasonable container design on soil gas detection values, and improving the accuracy of detection results has become the goal to be improved in work. Summary of the Invention

[0005] This application provides a soil headspace gas collection device, method, and soil gas detection system to solve the above-mentioned technical problems of inconvenient use in the prior art.

[0006] According to one aspect of this application, an embodiment provides a soil headspace gas collection device, including:

[0007] A container having a sample loading bottle mouth, and the sample loading bottle mouth is sealingly connected to a sample loading bottle cap;

[0008] A water injection bottle mouth opened on the first side of the container; the water injection bottle mouth is sealingly connected to a puncture water injection bottle cap; and

[0009] A gas extraction bottle mouth opened on the second side of the container; the gas extraction bottle mouth is sealingly connected to a puncture gas extraction bottle cap;

[0010] Wherein, when the container is placed in the first state, the gas extraction bottle mouth is higher than the water injection bottle mouth.

[0011] In one embodiment, the cross-section of the container is a sector; the first side and the second side are planes, and the water injection bottle mouth and the gas extraction bottle mouth are arranged on the plane.

[0012] In one embodiment, the first side and the second side are the same side.

[0013] In one embodiment, the puncture water injection bottle cap and the puncture gas extraction bottle cap are provided with parts for the needle to pass through.

[0014] In one embodiment, the part for the needle to pass through is set as a through hole.

[0015] In one embodiment, flexible sealing gaskets are provided between the puncture water injection bottle cap and the water injection bottle mouth, and between the puncture gas extraction bottle cap and the gas extraction bottle mouth.

[0016] According to one aspect of this application, an embodiment provides a soil gas detection system, including the soil headspace gas collection device as described in any one of the above; further including a hydrogen flame detector and a gas chromatograph for analyzing the components of soil gas; the hydrogen flame detector cooperates with the gas chromatograph.

[0017] According to one aspect of the present application, an embodiment provides a method for collecting soil headspace gas, using the soil headspace gas collection device described in any one of the above; the method for collecting soil headspace gas includes the following steps:

[0018] S1. Load an appropriate amount of saturated saline solution and sample into the container, seal the container and shake it.

[0019] S2. Let the container stand still until the gas in the gaseous and liquid states in the container reaches dynamic equilibrium. During the standing period, shake the container multiple times.

[0020] S3. Place the container in the first state, submerge the mouth of the water injection bottle in the liquid, and expose the mouth of the gas extraction bottle to the gas state; let the container stand still until the solid-liquid-gas three-phase separation occurs.

[0021] S4. While the first syringe pierces the needle-piercing water injection bottle cap to inject water into the container, the second syringe pierces the needle-piercing gas extraction bottle cap to extract gas from the container to collect soil gas.

[0022] In one embodiment, the method for collecting soil headspace gas further includes the following steps:

[0023] S5. Use a gas chromatograph with a hydrogen flame detector to measure the content of any one or more of light hydrocarbons, hydrogen, and carbon dioxide in the sample.

[0024] In one embodiment, the container is left to stand in an inverted manner with the sample loading bottle mouth facing downwards.

[0025] With the technical solution of the above embodiments of the present application, through the soil headspace gas collection device and the corresponding soil headspace gas collection method, soil gas that is free and weakly adsorbed on the surface of soil microparticles can be obtained time-saving, labor-saving, and efficiently. Further, through component analysis by the soil gas detection system, oil and gas reservoirs and gas reservoirs in the underlying strata can be effectively traced and predicted. This technical solution is applied in environmental protection, facilitating the collection of farmland soil, effectively obtaining soil interstitial gas, and performing gas detection. Description of the Drawings

[0026] Figure 1 is a schematic structural diagram of a soil headspace gas collection device in one embodiment;

[0027] Figure 2 is a collection schematic diagram of a soil headspace gas collection method in one embodiment;

[0028] Reference Signs:

[0029] 1 - sample loading bottle mouth; 2 - sample loading bottle cap; 3 - container; 4 - gas extraction bottle mouth; 5 - water injection bottle mouth; 6 - scale; 7 - needle-piercing water injection bottle cap; 8 - silica gel gasket; 9 - needle-piercing gas extraction bottle cap; 10 - first syringe; 11 - second syringe. Detailed Embodiments

[0030] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will detail this application with reference to the accompanying drawings and in combination with the embodiments.

[0031] To enable those skilled in the art of this technology to better understand the solution of this application, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0032] It should be noted that the terms "first", "second", etc. in this application are used to distinguish similar objects and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances for the embodiments of this application described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0033] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element can be directly on the other element, or there can also be an intermediate element. Moreover, in this application, when it is described that an element is "connected" to another element, the element can be "directly connected" to the other element, or "connected" to the other element through a third element.

[0034] Embodiment 1

[0035] Please refer to Figure 1 , an embodiment provides a soil headspace gas collection device, including: a container 3, a water injection bottle mouth 5, and a gas extraction bottle mouth 4; the container 3 has a sample loading bottle mouth 1, and the sample loading bottle mouth 1 is sealingly connected to a sample loading bottle cap 2; the water injection bottle mouth 5 is opened on a first side surface of the container 3; the water injection bottle mouth 5 is sealingly connected to a needle-piercing water injection bottle cap 7; the gas extraction bottle mouth 4 is opened on a second side surface of the container 3; the gas extraction bottle mouth 4 is sealingly connected to a needle-piercing gas extraction bottle cap 9. Wherein, when the container 3 is placed in a first state, the gas extraction bottle mouth 4 is higher than the water injection bottle mouth 5.

[0036] In one embodiment, the container 3 is a canned solid, and can further be a polycarbonate bottle. Preferably, a scale 6 is provided on the surface of the container 3. The sample loading bottle cap 2, the needle-piercing water injection bottle cap 7, and the needle-piercing gas extraction bottle cap 9 are threadedly connected to the bottle mouth. Regarding the sample loading bottle cap 2, preferably, a silica gel gasket 8 is provided inside it, and the sealing effect is better.

[0037] In one embodiment, the container 3 is an irregular container 3, and the cross-section of the container 3 is a sector. Preferably, the straight-edge angle of the transverse cross-section is 90 degrees. The first side surface and the second side surface are planes, and the water injection bottle mouth 5 and the gas extraction bottle mouth 4 are arranged on the planes.

[0038] In one embodiment, the first side surface and the second side surface are the same side surface. At this time, the water injection bottle mouth 5 and the gas extraction bottle mouth 4 are opened on the same side surface. Of course, the water injection bottle mouth 5 and the gas extraction bottle mouth 4 can also be opened on different side surfaces. When the cross-section of the container 3 is a sector, the water injection bottle mouth 5 is arranged on the first plane, and the gas extraction bottle mouth 4 is arranged on the second plane connected to the first plane. Preferably, the needle-piercing water injection bottle cap 7 and the needle-piercing gas extraction bottle cap 9 are on the same plane in the same direction and at the same height, and their positions are all close to the bottom of the container 3.

[0039] In one embodiment, the needle-piercing water injection bottle cap 7 and the needle-piercing gas extraction bottle cap 9 are provided with parts for the needle to pass through. Preferably, the part for the needle to pass through is set as a through hole. That is to say, the needle-piercing water injection bottle cap 7 and the needle-piercing gas extraction bottle cap 9 are of a hollow structure, and the hollow part is the through hole.

[0040] In one embodiment, flexible sealing gaskets are provided between the needle-piercing water injection bottle cap 7 and the water injection bottle mouth 5, and between the needle-piercing gas extraction bottle cap 9 and the gas extraction bottle mouth 4. Preferably, the sealing gasket is set as the silica gel gasket 8.

[0041] After collecting the soil sample, put the soil sample into the container 3 containing a certain amount (150 ml) of saturated saline, and add the soil sample until the concave surface of the saline rises to the 500 ml scale 6. Tighten the respective bottle caps with the silica gel gasket 8 in the container 3, invert it, and place it until it can be shaken and the air is extracted for the detection time. During the long-term placement of the container 3, the substances in the container 3 are divided into solid, liquid, and gas states in the static state; among them, the liquid just covers the water injection bottle mouth 5 and the gas extraction bottle mouth 4. At this time, the water (liquid) in the bottle can prevent the gas in the container 3 from escaping from the above two bottle mouths. After the container 3 is shaken and inverted for a period of time, when it is necessary to extract the gas substance in the container 3, place the container 3 flat with the fan-shaped surface as the bottom. At this time, insert the needle of the 20 ml first syringe 10 with the injection solution into the needle-piercing water injection bottle cap 7 for injection; at the same time, insert the needle of the emptied 10 ml second syringe 11 into the needle-piercing gas extraction bottle cap 9 for gas extraction, thereby completing the collection work of the soil gas.

[0042] The above-mentioned soil headspace gas collection device and the corresponding soil headspace gas collection method (hereinafter) can save time, effort, and efficiently obtain soil gas that is free and weakly adsorbed on the surface of soil microparticles. Furthermore, it can effectively track and predict oil and gas reservoirs and gas reservoirs in the underlying strata, and is also convenient for collecting farmland soil in environmental protection, effectively obtaining soil interstitial gas, and conducting gas detection.

[0043] Example Two

[0044] An embodiment provides a soil gas detection system, which includes the soil headspace gas collection device described in the above embodiment; it also includes a hydrogen flame detector and a gas chromatograph for analyzing the components of soil gas; the hydrogen flame detector cooperates with the gas chromatograph.

[0045] Among them, a gas chromatograph with a hydrogen flame detector (Agilent 7890A) can be used to measure the light hydrocarbon content, hydrogen content, and carbon dioxide content in the sample.

[0046] Example Three

[0047] An embodiment provides a soil headspace gas collection method, which uses the soil headspace gas collection device described in the above embodiment; the soil headspace gas collection method includes the following steps:

[0048] S1. Put an appropriate amount of saturated salt solution and sample into container 3, seal container 3, and shake it.

[0049] S2. Let container 3 stand still until the gas in the gaseous and liquid phases inside container 3 reaches dynamic equilibrium. During the standing period, shake container 3 several times.

[0050] S3. Place container 3 in the first state, submerge the mouth of the water injection bottle 5 in the liquid, and expose the mouth of the gas extraction bottle 4 to the gas; let container 3 stand still until the solid-liquid-gas three-phase separation occurs.

[0051] S4. While the first syringe 10 pierces the needle-piercing water injection bottle cap 7 to inject water into container 3, the second syringe 11 pierces the needle-piercing gas extraction bottle cap 9 to extract gas from container 3 to collect soil gas.

[0052] S5. Use a gas chromatograph with a hydrogen flame detector to measure the content of any one or more of light hydrocarbons, hydrogen, and carbon dioxide in the sample.

[0053] In one embodiment, container 3 is placed in an inverted manner with the mouth of the sample loading bottle 1 facing down.

[0054] Specifically: The water injection bottle mouth 5 and the air extraction bottle mouth 4 of the container 3 are tightly sealed with a silica gel gasket 8, a needle-piercing water injection bottle cap 7, and a needle-piercing air extraction bottle cap 9. The soil (or other solid substances) is filled into a saturated brine solution with a certain amount (150 ml) through the sample loading bottle mouth 1. The soil is filled until the concave surface of the solution in the container 3 rises to 500 ml. The sample loading bottle cap 2 with the silica gel gasket 8 is tightened, and then the container 3 is inverted and shaken; at this time, water (or solution) has covered the water injection bottle mouth 5 and the air extraction bottle mouth 4. After shaking for a period of time and then inverting until air extraction detection can be carried out, the fan-shaped surface of the container 3 can be placed as the bottom of the bottle; at this time, the substances in the container 3 are divided into three states: solid, liquid, and gas in the static state. The water injection bottle mouth 5 is just submerged in water (liquid or paste), and the air extraction bottle mouth 4 is exposed to the gas state. After that, the needle of the 20-ml first syringe 10 with the injection solution is inserted into the needle-piercing water injection bottle cap 7 to inject liquid into the liquid part in the container 3. At the same time, the needle of the emptied 10-ml second syringe 11 is inserted into the needle-piercing air extraction bottle cap 9 to extract air from the gas part in the container 3, thereby completing the air extraction and collection work of soil gas.

[0055] Example 4

[0056] Please refer to Figure 2 , an embodiment provides a method for collecting soil headspace gas. The technical solution of the present invention will be described below in the inventor's thinking, which is conducive to those skilled in the art to familiarize themselves with the idea of the present invention. Among them, for some technical key points, detailed explanations are given without omission, in order to enable those skilled in the art to fully understand the technical solution of the present invention.

[0057] The water injection bottle mouth 5 and the air extraction bottle mouth 4 of the container 3 are sealed with a needle-piercing water injection bottle cap 7 and a needle-piercing air extraction bottle cap 9 with a silica gel gasket 8. The container 3 is placed upright, and 150 ml of saturated brine is poured into the container 3 through the sample loading bottle mouth 1. The collected soil (or other solid substances) is filled from the sample loading bottle mouth 1 until the soil filled makes the concave surface of the solution in the container 3 rise to 500 ml, and then the sample loading bottle cap 2 with the silica gel gasket 8 / silica gel washer is tightened; then this container 3 is shaken and inverted for a period of time. At this time, the soil (or solid matter) is at the bottom, and water (or solution) is on the top, and has covered the water injection bottle mouth 5 and the air extraction bottle mouth 4. The top of the container 3 is gas; it is inverted and left stationary for a period of time (several days or weeks) until the gas in the gas state and the liquid state in the container 3 reaches a stable dynamic equilibrium. When air extraction detection is required, the container 3 can be placed with the fan-shaped surface as the bottom; at this time, the substances in the container 3 are divided into three states: solid, liquid, and gas in the static state, and the water injection bottle mouth 5 is just submerged in water (liquid or paste), and the air extraction bottle mouth 4 is exposed to the gas state. After that, the needle of the 20-ml first syringe 10 with the injection solution is inserted into the needle-piercing water injection bottle cap 7 to inject liquid, and at the same time, the needle of the emptied 10-ml second syringe 11 is inserted into the needle-piercing air extraction bottle cap 9 to extract air, thereby completing the air extraction and collection work of soil gas.

[0058] In the specific application of the above method, for the air extraction and collection, see Figure 2 as shown below. The process is as follows:

[0059] 1. Check the tightness and integrity of all bottle caps, bottle mouths and silicone gaskets 8;

[0060] 2. Use the needle with silicone gasket 8 to block the water injection bottle cap 7 and the needle extraction bottle cap 9 of the container 3 at the water injection bottle mouth 5 and the extraction bottle mouth 4. Place the container 3 upright, pour 150 ml of saturated saline into the container 3 through the sample loading bottle mouth 1, and seal it;

[0061] 3. Design 3 sampling points, namely WX-01 - WX-03. After reaching the designed points, open the sample loading bottle mouth 1, and load the soil at 1.6 meters collected from the sample loading bottle mouth 1 into the container 3 until the concave surface of the solution in the container 3 rises to 500 ml due to the loaded soil. Then tighten the sample loading bottle cap 2 with a silicone washer, and then invert the sample loading bottle mouth 1 of this container 3 downward.

[0062] 4. Invert and let it stand for 15 days, during which the container 3 is shaken. Until the gases in the gaseous and liquid states in the container 3 reach dynamic equilibrium. At this time, place the container 3 with the fan surface as the bottom. The substances in the container 3 are divided into solid, liquid and gaseous states under the static state. The water injection bottle mouth 5 is just submerged in the saturated saline, and the extraction bottle mouth 4 is exposed to the gaseous state. Insert the needle of the 20 ml first syringe 10 with injection solution into the needle water injection bottle cap 7 to inject water, and at the same time, insert the needle of the emptied 10 ml second syringe 11 into the needle extraction bottle cap 9 to extract gas. The gas volume is 9.0 mL. Thus, the air extraction and collection of soil gas is completed and transferred to a gas collection bottle for instrumental analysis.

[0063] 5. Use a gas chromatograph with a hydrogen flame detector (Agilent 7890A) to measure the light hydrocarbon content in the sample, and the results are shown in Table 1;

[0064] Table 1 Light hydrocarbon content in soil gas at WX-01 - WX-03 sampling points (μL / L, " / " indicates not detected)

[0065] [[ID=2**6]]

[0066] 6. Use a gas chromatograph with a hydrogen flame detector (Agilent 7890A) to measure the helium content in the sample, and the results are shown in Table 2;

[0067] Table 2 Helium, neon and hydrogen content in soil gas at WX-01 - WX-03 sampling points (μL / L)

[0068]

[0069] 7. Determine the carbon dioxide content in the sample using a gas chromatograph with a hydrogen flame detector (Agilent 7890A), and the results are shown in Table 3.

[0070] Table 3 Carbon Dioxide Content in Soil Gas at Sampling Points WX-01 - WX-03 (μL / L)

[0071]

[0072] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A soil headspace gas collection device, characterized in that, Comprising: A container having a sample loading bottle mouth, and the sample loading bottle mouth is sealingly connected to a sample loading bottle cap; A water injection bottle mouth opened on a first side of the container; the water injection bottle mouth is sealingly connected to a puncture water injection bottle cap; And An air extraction bottle mouth opened on a second side of the container; the air extraction bottle mouth is sealingly connected to a puncture air extraction bottle cap; Wherein, when the container is placed in a first state, the air extraction bottle mouth is higher than the water injection bottle mouth.

2. The soil headspace collection device according to claim 1, wherein The cross-section of the container is fan-shaped; the first side and the second side are planes, and the water injection bottle mouth and the air extraction bottle mouth are arranged on the plane.

3. The soil headspace gas collection device according to claim 1 or 2, characterized in that, The first side and the second side are the same side.

4. The soil headspace collection device according to claim 1, characterized in that, The puncture water injection bottle cap and the puncture air extraction bottle cap are provided with parts for the needle to pass through.

5. The soil headspace collection device according to claim 4, characterized in that, The part for the needle to pass through is set as a through hole.

6. A soil headspace collection device according to claim 4 or 5, characterized in that Flexible sealing gaskets are provided between the puncture water injection bottle cap and the water injection bottle mouth, and between the puncture air extraction bottle cap and the air extraction bottle mouth.

7. A soil gas detection system, characterized in that, Comprising the soil headspace gas collection device according to any one of claims 1-6; further comprising a hydrogen flame detector and a gas chromatograph for analyzing the components of soil gas; the hydrogen flame detector cooperates with the gas chromatograph.

8. A method for collecting soil headspace gas, characterized in that, Using the soil headspace gas collection device according to any one of claims 1-6; the soil headspace gas collection method comprises the following steps: S1. Load an appropriate amount of saturated saline solution and sample into the container, close the container and shake it; S2. Let the container stand until the gas in the gaseous and liquid states in the container reaches dynamic equilibrium, wherein the container is shaken multiple times during the standing period; S3. Place the container in a first state, submerge the water injection bottle mouth in the liquid, and expose the air extraction bottle mouth to the gas state; let the container stand until the solid-liquid-gas three-phase separation occurs; S4. While a first syringe pierces the puncture water injection bottle cap to inject water into the container, a second syringe pierces the puncture air extraction bottle cap to extract gas from the container to collect soil gas.

9. A method for collecting soil headspace gas according to claim 8, characterized in that, Further comprising the following steps: S5. Use a gas chromatograph with a hydrogen flame detector to measure the content of any one or more of light hydrocarbons, hydrogen, and carbon dioxide in the sample.

10. A method for collecting soil headspace gas according to claim 8 or 9, characterized in that, Let the container stand in an inverted manner with the sample loading bottle mouth facing down.

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