A horizontal hole aeration test device

Abstract

The present invention provides a horizontal hole aeration test device, including a model box filled with a simulated medium, a horizontal aeration pipe arranged in the simulated medium, a plurality of aeration holes provided in the horizontal aeration pipe, the horizontal aeration pipe connected to a gas pressure conveying component, a liquid injection port and a liquid discharge port provided in the model box, respectively used for the injection and discharge of organic pollutants, a water seepage component provided at both ends of the model box, used for seeping water into the simulated medium, a plurality of sampling holes provided on the side wall of the model box for sampling and analyzing the simulated medium, and a gas detection component provided on the top of the model box for detecting the gas in the model box. The present invention is conducive to the accurate characterization of the aeration influence area and the accurate prediction of the pollutant removal efficiency through model tests and theoretical analysis, and provides a technical reference for the efficient treatment of organic pollutants in groundwater by in-situ aeration remediation of horizontal holes.

Description

Technical Field

[0001] The invention relates to the technical field of environmental geological engineering, and in particular to a horizontal hole aeration test device. Background Art

[0002] With the rapid development of social economy, soil and groundwater are increasingly polluted by organic matter, among which volatile organic compounds (VOCs) are an important type of pollutants. The global annual crude oil production is about 4 billion tons, and 7% will enter the underground environment and cause soil and groundwater pollution. Therefore, research on groundwater organic pollution remediation technology is of great significance to water resource protection and environmental sustainable development.

[0003] Due to the complexity and concealment of organic pollution in groundwater, it is difficult to treat it. Among many technologies, in-situ aeration (IAS) is considered to be one of the most effective methods to remove VOCs in unsaturated soil and shallow groundwater. This method uses drilling technology to spray gas of a certain pressure and flow rate into the groundwater saturated zone. Under the action of buoyancy and pressure gradient, the gas migrates in the underground porous medium channel and carries dissolved phase and non-aqueous phase pollutants to the unsaturated zone, and then is collected and treated by gas phase extraction technology. Because IAS has the characteristics of not easy to produce secondary pollution, high efficiency and low consumption, it is widely used in site remediation projects.

[0004] At present, IAS mostly uses vertical drilling to aerate underground aquifers, and the pollution plume usually migrates with the flow of groundwater and tends to be distributed horizontally. In order to avoid leaving a "dead zone", the vertical well system needs to set up overlapping wells, but it will reduce the effective impact radius and increase the cost. Field applications have shown that under the same injection pressure, the injection capacity of horizontal holes is more than 10 times that of vertical holes. At the maximum injection rate, the impact area around the horizontal hole is 2 times larger than that of the vertical hole, and the "dead zone" can be effectively avoided. However, the current design and operation of horizontal hole IAS are mostly based on the limited field practice experience in the past to determine key parameters, such as aeration pressure, impact area, etc., lacking theoretical support for the mechanism and law of action. Existing model test studies are mainly based on vertical hole aeration, and the obtained theories and laws cannot be transplanted to horizontal hole aeration. Summary of the invention

[0005] The purpose of the present invention is to provide a horizontal aeration hole test scheme to address the deficiencies in the above-mentioned background technology, establish a horizontal hole IAS model theoretical system through model experiments and theoretical analysis, reveal the multiphase coupling and migration mechanism between soil particles, water, air and pollutants, which is conducive to the accurate characterization of the aeration influence area and the accurate prediction of the pollutant removal efficiency.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a horizontal hole aeration test device, including a model box, the model box is filled with a simulated medium, a horizontal aeration pipe is arranged in the simulated medium, the horizontal aeration pipe is provided with a plurality of aeration holes, the horizontal aeration pipe is connected to an air pressure conveying component, the model box is provided with an injection port and a discharge port, which are respectively used for the injection and discharge of organic pollutants, water seepage components are arranged at both ends of the model box, the water seepage components are used to infiltrate water into the simulated medium to simulate the flow of groundwater, a plurality of sampling holes are arranged on the side wall of the model box to sample and analyze the simulated medium, and a gas detection component is arranged on the top of the model box to detect the gas in the model box.

[0007] Furthermore, the model box is a three-dimensional hollow box with a rectangular cross section, the material of the model box is highly light-transmitting organic glass, and the simulation medium is transparent fused quartz sand or transparent soil.

[0008] Furthermore, the water infiltration component includes a first water storage tank and a second water storage tank respectively arranged at both ends of the model box, a permeable plate is arranged between the first water storage tank, the second water storage tank and the model box, a plurality of permeable holes are evenly arranged on the permeable plate, and the permeable holes are covered with a sand net at one end inside the model box.

[0009] Furthermore, the first water tank is connected to the first water head control box through an injection pipe, a flow meter is installed in the middle of the injection pipe, and the second water tank is connected to the second water head control box through an outlet pipe. The first water head control box and the second water head control box are used to control the water head of the first water tank and the second water tank respectively.

[0010] Furthermore, the first water head control box is connected with the water supply tank through a pumping pipe, and the pumping pipe is provided with a water pump, and the second water head control box is connected with the water collecting tank through a water outlet pipe; the first water head control box is provided with a first baffle, and the chamber on one side of the first baffle is connected with the water supply tank through a drain pipe, and the chamber on the other side of the first baffle is connected with the water injection pipe and the pumping pipe, and the first water head control box is connected with a first pulley lifting structure to control the water head height of the first water head control box through the first pulley lifting structure; the second water head control box is provided with a second baffle, and the chamber on one side of the second baffle is connected with the water outlet pipe, and the chamber on the other side of the second baffle is connected with the drain pipe, and the second water head control box is connected with a second pulley lifting structure to control the water head height of the second water head control box through the second pulley lifting structure.

[0011] Further, the first pulley lifting structure includes a first handwheel, a first pulley group, and a first slide, the first slide is fixed to the first water tank, the first water head control box is movably connected to the first slide, and the thin rope wrapped around the first handwheel passes around the first pulley group and is connected to the first water head control box; the second pulley lifting structure includes a second handwheel, a second pulley group, and a second slide, the second slide is fixed to the second water tank, the second water head control box is movably connected to the second slide, and the thin rope wrapped around the second handwheel passes around the second pulley group and is connected to the second water head control box.

[0012] Furthermore, the air pressure delivery assembly includes a one-way valve, a pressure display, a pressure regulating valve, and an air pump which are arranged in sequence and are connected to the horizontal aeration pipe through a hose.

[0013] Furthermore, an adjusting mechanism is installed in the model box, and the adjusting mechanism is used to adjust the height and inclination angle of the horizontal aeration pipe in the model box.

[0014] Furthermore, each of the sampling holes on the model box is equipped with a quick connector, and a detachable rubber plug is installed at the quick connector. When sampling, the capillary is inserted into the sampling hole at different depths for sampling.

[0015] Furthermore, a removable cover is provided on the top of the model box; a plurality of groups of parallel partitions intersecting vertically and horizontally are provided at the lower part of the cover, the parallel partitions are used to evenly divide the model box into several sub-units, an outlet valve is provided on the top of each sub-unit on the cover, the outlet valve is respectively connected to a gas flow sensor and an activated carbon filter, the gas flow sensor is used to monitor the gas flow value in real time to obtain the airflow distribution on a certain height plane, the activated carbon filter is used to adsorb organic pollutants, and after extraction with carbon disulfide extractant, the pollutant removal flux of each sub-unit and the total removal rate of pollutants in the affected area are obtained by gas chromatography-mass spectrometry analysis.

[0016] The above scheme of the present invention has the following beneficial effects:

[0017] The horizontal aeration test device provided by the present invention reasonably arranges horizontal aeration pipes in a model box, which is different from the conventional vertical hole point source aeration method, has certain spatial characteristics, comprehensively considers the influence of borehole morphology, formation heterogeneity and groundwater flow on gas migration law, and can observe the dynamic evolution process of multiphase flow field in horizontal hole aeration from the perspective of overall distribution-local characteristics-single gas phase-multiphase coupling at multiple levels and angles; by adjusting the water level and the height of the horizontal aeration pipe, the distance between the horizontal aeration pipe and the parallel partition is changed while ensuring that the aeration depth remains unchanged, so as to measure the airflow distribution in planes of different heights; by adjusting the spatial morphology of the horizontal aeration pipe, the gas phase migration law under different borehole inclination angles caused by construction errors is observed; the present invention selects typical volatile organic pollutants to be injected into the formation medium, and can well study the removal efficiency of pollutants in horizontal holes and the mass transfer law of multiple components, and provides a technical reference for the efficient treatment of organic pollutants in groundwater remediation by in-situ aeration of horizontal holes.

[0018] Other beneficial effects of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 It is a schematic diagram of the sampling hole of the present invention;

[0021] Figure 3 It is a schematic diagram of the partition subunit of the present invention.

[0022] [Description of Reference Numerals]

[0023] 1- model box; 2- cover plate; 3- sample outlet; 4- injection port; 5- discharge port; 6- first water storage tank; 7- second water storage tank; 8- water permeable hole; 9- first water head control box; 10- water injection pipe; 11- flow meter; 12- second water head control box; 13- water outlet pipe; 14- water pump; 15- water supply tank; 16- water pump; 17- drainage pipe; 18- water collection tank; 19- drainage pipe; 20- first hand wheel; 21 -first front pulley; 22-first rear pulley; 23-second handwheel; 24-second front pulley; 25-second rear pulley; 26-horizontal aeration pipe; 27-hose; 28-check valve; 29-pressure display; 30-pressure regulating valve; 31-air pump; 32-regulating mechanism; 33-sampling hole; 34-quick connector; 35-parallel partition; 36-air outlet valve; 37-gas flow sensor; 38-activated carbon filter. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc., are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a locking connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] like Figure 1 As shown, an embodiment of the present invention provides a horizontal hole aeration test device, including a model box 1. The model box 1 is a three-dimensional hollow box with a rectangular cross-section, and the box material is made of highly light-transmitting organic glass, which is convenient for observing the interior during the test. A removable cover 2 is provided on the top of the model box 1, which is used to load quartz sand media and the like after opening. A sample discharge port 3 is provided at the center of the bottom plate of the model box 1, which is convenient for removing the filled quartz sand medium after the test. An injection port 4 and a discharge port 5 are respectively provided at the left and right positions of the bottom of the model box 1, so that volatile organic pollutants, such as benzene solution, can be slowly injected into the quartz sand medium through the injection port 4 for testing. Before injection, the removable cover 2 needs to be closed to form a sealed environment in the box.

[0028] In addition, a water storage tank, a water head control box, a water supply tank 15 and a water collecting tank 18 are also provided, and all are equipped with sealing covers to ensure good sealing of the overall device.

[0029] In this embodiment, the first water storage tank 6 and the second water storage tank 7 are arranged on the two end surfaces of the model box 1, and a plurality of water permeable holes 8 are evenly arranged on the permeable plate between the two water storage tanks and the model box 1. Water penetrates into the medium in the model box 1 through the water permeable holes 8, and a layer of sand mesh is covered on one end of the water permeable hole 8 located inside the box body to accurately simulate the state in which the formation medium cannot enter the water storage tank. Among them, the first water storage tank 6 is connected to the first water head control box 9 through the water injection pipe 10, and a flow meter 11 is installed in the middle of the water injection pipe 10 to monitor the flow of water; the second water storage tank 7 is connected to the second water head control box 12 through the outlet pipe 13. Therefore, the water heads of the first water storage tank 6 and the second water storage tank 7 are controlled by the first water head control box 9 and the second water head control box 12 respectively to control the penetration of water into the model box 1.

[0030] In this embodiment, the first water head control box 9 is connected to the water supply tank 15 through the water pumping pipe 14, and the water pumping pipe 14 is equipped with a water pump 16, which relies on the water pump 16 to send the water pressure in the water supply tank 15 to the first water head control box 9. Correspondingly, the second water head control box 12 is connected to the water collecting tank 18 through the drainage pipe 17, so that the water flowing into the second water head control box 12 is further collected in the water collecting tank 18.

[0031] As a further improvement, in this embodiment, a first partition is provided in the middle of the first water head control box 9, and the first water head control box 9 is divided into two chambers by the first partition. Among them, one side chamber is connected to the water supply tank 15 through the drain pipe 19, and the other side chamber is connected to the water injection pipe 10 and the pumping pipe 14. The first water head control box 9 controls the water head height through the first pulley lifting structure. A second partition is also provided inside the second water head control box 12, and the separated side chamber is connected to the outlet pipe 13, and the other side chamber is connected to the drain pipe 17. The water head height of the second water head control box 12 can be controlled by adjusting the second pulley lifting structure. Finally, the model box 1 forms a stable seepage flow for simulating the flow of groundwater. It can be understood that the first partition and the second partition are used to ensure the stability of the water level inside the first water head control box 9 and the second water head control box 12, respectively. Specifically in this embodiment, the first pulley lifting structure includes a first hand wheel 20, a first front pulley 21, a first rear pulley 22, a first slideway, etc., wherein the first slideway is fixed to the outer wall of the first water storage tank 6, the first water head control box 9 is movably connected to the first slideway, and the thin rope wound around the first hand wheel 20 passes around the first front pulley 21 and the first rear pulley 22 and is connected to the first water head control box 9. Shaking the first hand wheel 20 to retract and release the thin rope, thereby rotating the first front pulley 21 and the first rear pulley 22, so that the first water head control box 9 moves up and down along the first slideway, and the water head height changes, which is convenient for adjusting the water head height. The second pulley lifting structure is similar, including a second hand wheel 23, a second front pulley 24, a second rear pulley 25, a second slideway, etc., which will not be repeated here.

[0032] In this embodiment, a horizontal aeration pipe 26 is arranged in the middle of the bottom of the model box 1. It is a cylindrical cavity of a preset length, and multiple aeration holes are evenly processed radially. At the same time, a layer of gauze is covered on the periphery of the aeration hole to prevent quartz sand particles from entering the aeration hole. The horizontal aeration pipe 26 is connected to the one-way valve 28, the pressure display 29, the pressure regulating valve 30, and the air pump 31 in sequence through the hose 27 to pump the gas of the preset pressure into the horizontal aeration pipe 26, thereby simulating the IAS method.

[0033] As a further improvement, in this embodiment, an adjusting mechanism 32 is further installed in the model box 1 , and the height and inclination angle of the horizontal aeration pipe 26 in the box can be adjusted by the adjusting mechanism 32 to simulate more test conditions of the horizontal aeration pipe 26 .

[0034] In this embodiment, a large number of sampling holes 33 (specifically 72 in this embodiment) are evenly distributed on the side surface of the model box 1. Figure 2 As shown, each sampling hole 33 is equipped with a quick connector 34 and sealed with a rubber plug. When measuring data, the rubber plug is opened, and a capillary is inserted into the sampling hole 33 at different depths to take samples. Then, a dissolved oxygen meter is used to measure the dissolved oxygen values ​​at different positions inside the model box 1, or a gas chromatography-mass spectrometry instrument is used to test and analyze the samples to obtain the spatial distribution of organic pollutants.

[0035] At the same time Figure 3 As shown, in this embodiment, a plurality of groups of parallel partitions 35 intersecting vertically and horizontally are provided at the lower part of the detachable cover plate 2 of the model box 1. After the cover plate 2 is covered, the box body is evenly divided into several sub-units (48 in this embodiment). An outlet valve 36 is provided at the top of each sub-unit, which is respectively connected to a gas flow sensor 37 and an activated carbon filter 38. Among them, the gas flow sensor 37 is used to monitor the gas flow value in real time and obtain the airflow distribution on a certain height plane. The activated carbon filter 38 can adsorb the pollutant benzene, and after extraction with a carbon disulfide extractant, it is analyzed by a gas chromatography-mass spectrometer to obtain the pollutant removal flux of each sub-unit and the total removal rate of pollutants in the affected area.

[0036] As described above, the horizontal hole aeration test device provided in this embodiment is different from the conventional vertical hole point source aeration method, has certain spatial characteristics, and comprehensively considers the influence of borehole morphology, formation heterogeneity and groundwater flow on gas migration law. It can observe the dynamic evolution process of multiphase flow field in horizontal hole aeration from the overall distribution-local characteristics-single gas phase-multiphase coupling multi-level and multi-angle. By adjusting the water level and the height of the horizontal aeration tube 26, while ensuring that the aeration depth remains unchanged, the distance between the horizontal aeration tube 26 and the parallel partition 35 is changed, so as to measure the airflow distribution of planes at different heights. By adjusting the spatial morphology of the horizontal aeration tube 26, the gas phase migration law under different borehole inclination angles caused by construction errors is observed. This embodiment selects typical volatile organic pollutants to be injected into the formation medium, which can well study the removal efficiency of pollutants in horizontal holes and the mass transfer law of multiple components, and provides a technical reference for the efficient treatment of organic pollutants in groundwater by in-situ aeration remediation of horizontal holes.

[0037] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A horizontal hole aeration test device, characterized in that: The invention comprises a model box, wherein the model box is filled with a simulated medium, a horizontal aeration pipe is arranged in the simulated medium, a plurality of aeration holes are provided in the horizontal aeration pipe, the horizontal aeration pipe is connected to a gas pressure conveying component, a liquid injection port and a liquid discharge port are provided in the model box, respectively used for the injection and discharge of organic pollutants, a water seepage component is provided at both ends of the model box, the water seepage component is used for seeping water into the simulated medium to simulate the flow of groundwater, a plurality of sampling holes are provided on the side wall of the model box to sample and analyze the simulated medium, and a gas detection component is provided on the top of the model box to detect the gas in the model box; The water seepage assembly comprises a first water storage tank and a second water storage tank respectively arranged at both ends of the model box, a water permeable plate is arranged between the first water storage tank, the second water storage tank and the model box, a plurality of water permeable holes are evenly arranged on the water permeable plate, and the water permeable holes are covered with a sand net at one end inside the model box; The model box is also equipped with an adjustment mechanism, which is used to adjust the height and inclination of the horizontal aeration pipe in the model box; A detachable cover is provided on the top of the model box; a plurality of groups of parallel partitions intersecting vertically and horizontally are provided at the bottom of the cover, the parallel partitions are used to evenly divide the model box into a number of sub-units, an outlet valve is provided on the top of each sub-unit on the cover, the outlet valve is respectively connected to a gas flow sensor and an activated carbon filter, the gas flow sensor is used to monitor the gas flow value in real time and obtain the airflow distribution on a certain height plane, the activated carbon filter is used to adsorb organic pollutants, and after extraction with carbon disulfide extractant, the pollutant removal flux of each sub-unit and the total removal rate of pollutants in the affected area are obtained by gas chromatography-mass spectrometry analysis.

2. A horizontal hole aeration test device according to claim 1, characterized in that: The model box is a three-dimensional hollow box with a rectangular cross section. The material of the model box is highly light-transmitting organic glass, and the simulation medium is transparent fused quartz sand or transparent soil.

3. A horizontal hole aeration test device according to claim 1, characterized in that: The first water tank is connected to the first water head control box through an injection pipe, a flow meter is installed in the middle of the injection pipe, and the second water tank is connected to the second water head control box through an outlet pipe. The first water head control box and the second water head control box are used to control the water head of the first water tank and the second water tank respectively.

4. A horizontal hole aeration test device according to claim 3, characterized in that: The first water head control box is connected with the water supply tank through a pumping pipe, and the pumping pipe is provided with a water pump. The second water head control box is connected with the water collecting tank through a water outlet pipe; the first water head control box is provided with a first baffle, and the chamber on one side of the first baffle is connected with the water supply tank through a drain pipe, and the chamber on the other side of the first baffle is connected with the water injection pipe and the pumping pipe. The first water head control box is connected with a first pulley lifting structure to control the water head height of the first water head control box through the first pulley lifting structure; the second water head control box is provided with a second baffle, and the chamber on one side of the second baffle is connected with the water outlet pipe, and the chamber on the other side of the second baffle is connected with the drain pipe. The second water head control box is connected with a second pulley lifting structure to control the water head height of the second water head control box through the second pulley lifting structure.

5. A horizontal hole aeration test device according to claim 4, characterized in that: The first pulley lifting structure includes a first handwheel, a first pulley group, and a first slide, the first slide is fixed to the first water tank, the first water head control box is movably connected to the first slide, and the thin rope wrapped around the first handwheel passes around the first pulley group and is connected to the first water head control box; the second pulley lifting structure includes a second handwheel, a second pulley group, and a second slide, the second slide is fixed to the second water tank, the second water head control box is movably connected to the second slide, and the thin rope wrapped around the second handwheel passes around the second pulley group and is connected to the second water head control box.

6. A horizontal hole aeration test device according to claim 1, characterized in that: The air pressure delivery assembly comprises a one-way valve, a pressure display, a pressure regulating valve, and an air pump which are arranged in sequence, and is connected to the horizontal aeration pipe through a hose.

7. A horizontal hole aeration test device according to claim 1, characterized in that: Each of the sampling holes on the model box is equipped with a quick connector, and a detachable rubber plug is installed at the quick connector. When sampling, the capillary is inserted into the sampling hole at different depths for sampling.

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