Simulation experiment device and method for basalt-soil remediation shallow surface CO2 leakage

Abstract

The invention relates to the technical field of geological sequestration and environmental remediation, and particularly discloses a simulation experiment device and method for CO2 leakage of a basalt-soil remediation shallow earth surface, the device comprises a composite reaction module, a CO2 leakage simulation module and a monitoring module, the composite reaction module comprises a reaction cabin, a temperature control device and a humidity control device are arranged in the reaction cabin; a plurality of distributed injection holes are formed in the bottom of the reaction cabin; the CO2 leakage simulation module comprises a CO2 gas source communicated with the distributed injection hole and a mass flow controller arranged at the gas outlet end of the CO2 gas source; the monitoring module comprises a CO2 gas concentration sensor and a plurality of resistivity sensors. By designing the layered multi-physics field coupling reactor, temperature, pressure and seepage fields under real geological conditions are simulated, quantitative evaluation of CO2 absorption efficiency is achieved, the limitation that single carbon fixing efficiency reflects the repairing effect is overcome, and an experimental paradigm is provided for geological sequestration shallow earth surface leakage repairing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geological storage and environmental remediation, in particular to a basalt-soil remediation shallow surface CO2 leakage simulation experiment device and method. BACKGROUND

[0002] As a key technology for carbon dioxide (CO2) emission reduction, geological storage faces the risk of shallow surface leakage, which may lead to atmospheric pollution, soil acidification and groundwater deterioration. Basalt and other basic rocks are rich in alkaline metal elements such as calcium, magnesium and iron. After mixing with soil, they can solidify CO2 into stable carbonates through mineral carbonation reaction, which is an environmentally friendly passive remediation strategy.

[0003] Accurate evaluation of the effect of this remediation technology depends on an experimental device that can truly simulate the shallow surface leakage scenario and accurately control the reaction conditions. The occurrence efficiency and reaction kinetics of mineral carbonation are controlled by the multi-physical field coupling environment, including: CO2 diffusion path and flux (affecting reaction contact efficiency), soil humidity (controlling dissolution and ion migration), temperature gradient (affecting reaction rate) and medium compaction degree (affecting pore structure and gas transport). Therefore, the experimental device needs to have the ability to simulate the real leakage path, accurately control the above key parameters, and monitor the dynamic changes of the reaction process in real time.

[0004] The current experimental device has significant limitations and cannot meet the above needs, including: (1) The traditional top single-point injection method does not match the actual CO2 upward leakage path from the deep, and cannot reflect the real diffusion behavior; (2) The control of key reaction parameters such as humidity, temperature gradient and compaction degree is missing or single; (3) The evaluation relies too much on a single carbon fixation efficiency indicator, ignoring the ability of the remediation system to block CO2 diffusion and the stability of the medium structure after the reaction; (4) Lack of in-situ, real-time, layered monitoring capability, making it difficult to dynamically track the mineralization process. SUMMARY

[0005] In order to truly simulate the CO2 leakage path, couple and control the multi-physical field parameters, integrate multi-dimensional dynamic monitoring, and establish a comprehensive quantitative evaluation system, the present application provides a basalt-soil remediation shallow surface CO2 leakage simulation experiment device and method.

[0006] The basalt-soil remediation shallow surface CO2 leakage simulation experiment device provided by the present application adopts the following technical scheme: A basalt-soil remediation shallow surface CO2 leakage simulation experiment device, comprising: A composite reaction module, comprising a reaction chamber, wherein a temperature control device and a humidity control device are arranged in the reaction chamber, and a plurality of dispersed injection holes are arranged at the bottom of the reaction chamber. A CO2 leakage simulation module, comprising a CO2 gas source in communication with the distributed injection holes, and a mass flow controller arranged at the gas outlet end of the CO2 gas source; A monitoring module, comprising a CO2 gas concentration sensor arranged at the top of the reaction chamber, and a plurality of resistivity sensors arranged at the inner side wall of the reaction chamber along the height direction of the reaction chamber; the side wall of the reaction chamber is provided with a plurality of sampling ports arranged along the height direction, and the number and height of the sampling ports are consistent with those of the resistivity sensors.

[0007] The present application simulates the real path of CO2 leakage from the deep to the upper through the bottom distributed injection holes; integrates the temperature / humidity control device to accurately regulate the mineralization reaction environment; combines the top CO2 concentration sensor with the layered resistivity sensor to realize the in-situ dynamic correlation analysis of the leakage gas distribution, soil conductivity change and mineral generation process, and overcome the defects of simulation distortion and single monitoring dimension of traditional devices.

[0008] Further, the distributed injection holes are arranged in an array at the bottom of the reaction chamber, and a porous medium is arranged above the distributed injection holes at the bottom of the reaction chamber.

[0009] The arrayed distributed injection holes and the porous medium cooperate to realize the uniform penetration of CO2 from bottom to top, simulate the diffuse upward percolation behavior of CO2 in the shallow soil, avoid the gas channeling effect caused by single-point injection, and ensure that the experimental data are close to the actual geological scenario.

[0010] Further, the temperature control device comprises an electric heating layer and a temperature sensor embedded in the inner side wall of the reaction chamber.

[0011] The embedded wall type electric heating layer can control temperature in sections, and construct a 20-60°C temperature gradient in the vertical direction of the reaction chamber to simulate the real soil profile; combined with closed-loop regulation of the temperature sensor, the temperature sensitivity requirement of mineral carbonation reaction is met, and the simulation accuracy of reaction kinetics is significantly improved.

[0012] Further, the humidity control device comprises a spraying device arranged at the top of the reaction chamber, the spraying device is connected with a water source, and the humidity control device further comprises a humidity sensor.

[0013] The top atomizing spraying device cooperates with the humidity sensor to realize a humidity control accuracy of ±2%, ensure the uniform distribution of water molecules in the basalt-soil medium, optimize the reaction chain of CO2 dissolution-ion migration-carbonate precipitation, and avoid the mineralization efficiency deviation caused by local dry / wet areas.

[0014] Further, the reaction cabin top is connected with an air outlet pipe, the air outlet pipe is installed with a one-way valve for controlling the pressure in the reaction cabin; the reaction cabin is provided with a gas pressure sensor.

[0015] The one-way valve of the air outlet pipe maintains the cabin pressure at 0.5-2 MPa to simulate the condition of shallow overburden rock and prevent gas from escaping; the pressure sensor monitors the cabin pressure fluctuation in real time to ensure the stability of CO2 partial pressure and provide a thermodynamic consistency environment for the mineral carbonation reaction.

[0016] Further, a plurality of the resistivity sensors are distributed at equal intervals along the height direction of the reaction cabin, and a plurality of the sampling ports are distributed at equal intervals along the height direction of the reaction cabin.

[0017] The resistivity sensors and the sampling ports are arranged at equal intervals and elevations, so that the gas composition and resistivity data at the same depth are strictly spatially corresponding, and the vertical evolution law of the CO2 diffusion-mineralization reaction is accurately analyzed.

[0018] Further, the simulation experiment device further comprises a data acquisition and recording system connected with the monitoring module for recording and processing the data collected by the monitoring module.

[0019] The data acquisition system automatically associates the temperature, humidity, pressure, resistivity and CO2 concentration data, and then comprehensively evaluates the effect of the basalt-soil mixed system on repairing shallow surface CO2 leakage.

[0020] Further, the reaction cabin is provided with detachable layered partitions for simulating different geological horizons.

[0021] By simulating different geological horizons, the cross-interface migration and reaction process of leaked CO2 in heterogeneous strata are truly restored, and experimental basis is provided for site-specific repair schemes.

[0022] The application also provides a simulation experiment method for repairing shallow surface CO2 leakage by using the basalt-soil mixed system, which adopts the simulation experiment device for repairing shallow surface CO2 leakage by using the basalt-soil mixed system, and the experimental method comprises the following steps: A porous medium is laid at the bottom of the reaction cabin, then a quartz sand layer and a basalt-soil mixed layer are filled in sequence to the target height and compacted to the target compactness, the humidity of the basalt-soil mixed layer is adjusted to the target humidity by the humidity control device, and the basalt-soil mixed layer is adjusted to the target temperature gradient by the temperature control device; CO2 is introduced and adjusted to the target pressure, and the constant / pulse leakage rate of CO2 is set by the mass flow controller; The CO2 concentration in the reaction cabin, the resistivity and temperature and humidity of the basalt-soil mixed layer are monitored and recorded in real time, and the gas samples are collected regularly through the sampling ports; After the reaction, the carbon fixation efficiency is calculated according to the CO2 consumption and the carbonate generation before and after the reaction, the CO2 diffusion rate of the pure soil system, the CO2 diffusion rate of the basalt-soil mixed system and the CO2 diffusion retardation coefficient are calculated according to the change of CO2 concentration, and the structure stability coefficient is calculated according to the resistivity before and after the reaction; the basalt particle-soil mixed system repair effect is evaluated by comprehensively considering the carbon fixation efficiency, the CO2 diffusion retardation coefficient and the structure stability coefficient.

[0023] Further, the target temperature gradient is 20-60°C, the target pressure is 0.5-2 MPa, and the leakage rate is 0.1-10 mL / min.

[0024] To sum up, the present application includes at least one of the following beneficial technical effects: 1. Compared with the existing top single-point injection device, the present application adopts a bottom dispersed injection hole combined with a porous medium to accurately simulate the real leakage path of CO2 from the geological storage layer to the shallow surface soil, and in combination with a detachable layered partition design, the present application can more truly reflect the diffusion, migration behavior of the leaked gas in different geological layers and the contact reaction process with the repair material, thereby providing an experimental basis close to the actual scene for the repair effect evaluation. 2. The device integrates a humidity control device, a temperature control device and a mass flow controller to realize the coordinated and accurate control of the key environmental parameters of the mineral carbonation reaction, simulate the temperature, humidity, pressure and seepage field under the real geological conditions, and through the layered arrangement of the resistivity sensor and the sampling port, the CO2 concentration distribution at different depths and the change of soil resistivity can be monitored in situ, in real time and dynamically, thereby overcoming the defects of the traditional device, such as single monitoring dimension and inability to track the reaction process in real time, and providing multi-dimensional data support for mechanism research. 3. The present application proposes a comprehensive quantitative index system, which not only calculates the carbon fixation efficiency to evaluate the CO2 mineralization amount, but also quantifies the blocking ability of the repair system to the leaked gas through the CO2 diffusion retardation coefficient, and calculates the structure stability coefficient based on the change of resistivity before and after the reaction to evaluate the reinforcement effect of the mineral precipitation on the medium structure. The coordinated evaluation of the three indexes (carbon fixation efficiency, diffusion retardation coefficient and structure stability coefficient) comprehensively and objectively reflects the comprehensive repair performance of the basalt-soil mixed system in carbon sequestration, leakage blocking and soil stabilization, thereby overcoming the evaluation deviation caused by relying on a single carbon fixation efficiency, and providing a scientific, reliable and standardized experimental evaluation paradigm for the selection, optimization and engineering application of the geological storage leakage repair technology. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of the overall structure of a simulation experiment device for repairing shallow surface CO2 leakage by basalt-soil according to an embodiment of the present application; Figure 2is a structure schematic view of the simulation experiment device for repairing shallow surface CO2 leakage by basalt-soil from another angle.

[0026] The figure mark: 1, base; 101, CO2 gas source; 102, mass flow controller; 103, gas inlet pipe; 104, sealing ring one; 105, dispersed injection hole; 106, porous medium; 2, reaction cabin; 201, spraying device; 202, sealing cover; 203, sealing ring two; 204, spraying pump; 205, counterforce screw rod; 206, heating layer; 207, scale; 3, data acquisition and recording system; 301, air extraction pipe; 302, CO2 gas concentration sensor; 303, air outlet pipe; 304, one-way valve; 305, valve; 306, sampling port; 307, resistivity sensor; 4, pressure column. DETAILED DESCRIPTION

[0027] The following will be combined with the accompanying Figures 1-2 The application is further described in detail.

[0028] The application discloses a simulation experiment device for repairing shallow surface CO2 leakage by basalt-soil. Figure 1 And Figure 2 The device comprises a composite reaction module, a CO2 leakage simulation module, a monitoring module and a data acquisition and recording system 3.

[0029] Referring to Figure 1 And Figure 2 The composite reaction module comprises a reaction cabin 2 fixed on the base 1, and the reaction cabin 2 is in a cylindrical shape, and the bottom part of the reaction cabin 2 is sealed with the base 1 by using a sealing ring one 104. The upper part of the reaction cabin 2 is open and detachably installed with a sealing cover 202, and the sealing cover 202 is connected with the base 1 by using a counterforce screw rod 205, the counterforce screw rod 205 is used for pressing the sealing cover 202 to the upper open end of the reaction cabin 2, and the reaction cabin 2 and the sealing cover 202 are sealed by using a sealing ring two 203. The inside of the reaction cabin 2 is a space for the basalt-soil composite system to react with CO2, when the basalt-soil is filled into the reaction cabin 2, the basalt-soil is compacted by a pressure column 4, and the filling height of the basalt-soil is observed by a scale 207 on the inner side wall of the reaction cabin 2.

[0030] Referring to Figure 1 And Figure 2, the bottom of the reaction chamber 2 is provided with a plurality of array distributed dispersed injection holes 105, and the bottom of the reaction chamber 2 is paved with a porous medium 106 above the dispersed injection holes 105. The CO2 leakage simulation module comprises a CO2 gas source 101, the CO2 gas source 101 is communicated with the dispersed injection hole 105 through the gas inlet pipe 103, and the mass flow controller 102 is installed on the gas inlet pipe 103. The array distributed dispersed injection holes 105 cooperate with the porous medium 106 to realize the uniform penetration of CO2 in the reaction chamber 2 from bottom to top, and simulate the dispersion upward seepage behavior of CO2 in the shallow surface soil.

[0031] Referring to Figure 1 , the top of the reaction chamber 2 is connected with the gas outlet pipe 303 and the air exhaust pipe 301, the gas outlet pipe 303 is provided with a one-way valve 304 for controlling the pressure in the reaction chamber 2; the reaction chamber 2 is provided with a gas pressure sensor.

[0032] Referring to Figure 1 and Figure 2 , the reaction chamber 2 is provided with a temperature control device and a humidity control device. The temperature control device comprises an electric heating layer 206 embedded in the inner side wall of the reaction chamber 2 and a temperature sensor (which can be arrayed at different depths of the reaction chamber 2), the electric heating layer 206 can control temperature in sections, and a temperature gradient is constructed in the vertical direction of the reaction chamber 2 to simulate the real soil profile, and the temperature sensor realizes closed-loop regulation and control of temperature. The humidity control device comprises a spraying device 201 arranged at the top of the reaction chamber 2, the spraying device 201 is connected with a water source through a spraying pump 204 to realize quantitative water spraying, and the spraying device 201 cooperates with a humidity sensor (which can be arrayed at different depths of the reaction chamber 2) to realize humidity control of the basalt-soil medium.

[0033] Referring to Figure 1 and Figure 2 , the monitoring module comprises a CO2 gas concentration sensor 302 and a plurality of resistivity sensors 307, the CO2 gas concentration sensor 302 is arranged at the top of the reaction chamber 2 for real-time monitoring of CO2 concentration and CO2 flux at the top of the reaction chamber 2. A plurality of resistivity sensors 307 are arranged at the inner side wall of the reaction chamber 2 along the height direction of the reaction chamber 2 (buried at depths of 5, 10, 15 and 20 cm); a plurality of sampling ports 306 are arranged at the side wall of the reaction chamber 2 along the height direction, the number of the sampling ports 306 is the same as that of the resistivity sensors 307 and the position height is consistent (buried at depths of 5, 10, 15 and 20 cm), and a valve 305 is installed on each sampling port 306.

[0034] In order to simulate different geological layers, the reaction chamber 2 is also provided with a detachable layered partition plate (not shown in the figure).

[0035] The data acquisition and recording system 3 is connected with the monitoring module and various sensors (including a CO2 gas concentration sensor 302, a resistivity sensor 307, a temperature sensor, a humidity sensor, a gas pressure sensor, etc.), and is used to record and process the data collected by the monitoring module.

[0036] A simulation experiment method for repairing shallow surface CO2 leakage by using basalt-soil is implemented by using the above device, and includes the following steps: Step 1: A porous medium is laid at the bottom of the reaction chamber, and then a quartz sand layer and a basalt-soil mixed layer (the mass ratio of basalt to soil is 1:4, and the particle size of basalt is less than 0.5 mm) are sequentially filled to a target height and compacted to a target compactness. The humidity of the basalt-soil mixed layer is adjusted to 50% by the humidity control device, and the basalt-soil mixed layer is adjusted to a target temperature gradient (20-60°C) by the temperature control device; CO2 is introduced into the reaction chamber, and the constant / pulse leakage rate of CO2 is set to 10 mL / min by the mass flow controller, and the pressure buildup pressure is adjusted to 5 bar by the one-way valve.

[0037] Step 2: continuously react for 7 days, and monitor and record the CO2 concentration in the reaction chamber, the resistivity and temperature and humidity of the basalt-soil mixed layer in real time, and periodically collect gas samples through the sampling port.

[0038] Step 3: After the reaction is completed, the carbon fixation efficiency is calculated according to the CO2 consumption and the amount of carbonate generated before and after the reaction, the CO2 diffusion rate of the pure soil system, the CO2 diffusion rate of the basalt-soil mixed system, and the CO2 diffusion retardation coefficient are calculated according to the change of CO2 concentration, and the structural stability coefficient is calculated according to the resistivity before and after the reaction; the repair effect of the basalt particle-soil mixed system is evaluated by comprehensively considering the carbon fixation efficiency, the CO2 diffusion retardation coefficient and the structural stability coefficient, which specifically includes: The carbon fixation efficiency is calculated according to the CO2 consumption and the amount of carbonate generated before and after the reaction:

[0039] Wherein: is the mass of CO2 participating in the mineralization reaction, which is calculated by XRD or TGA quantitative carbonate mineral; is the mass of injected CO2, which is calculated by the cumulative flow of the mass flow controller.

[0040] The CO2 diffusion rate D of the pure soil system is calculated according to Fick's law according to the change of CO2 gas concentration p and the CO2 diffusion rate D of the mixed system m , and then the CO2 diffusion retardation coefficient is calculated:

[0041] According to the measured pre-reaction resistivity R b and post-reaction resistivity R a , the structure stability coefficient is calculated:

[0042] The comprehensive carbon fixation efficiency , CO2 diffusion retardation coefficient and structure stability coefficient , the basalt particle-soil mixed system repair effect is evaluated: .

[0043] The application simulates the real path of CO2 leakage from the deep to the upper through the bottom dispersed injection hole; integrates the temperature / humidity control device to accurately regulate the mineralization reaction environment; combines the top CO2 concentration sensor and the layered resistivity sensor to realize the in-situ dynamic correlation analysis of the leakage gas distribution, the soil conductivity change and the mineral generation process, overcomes the defects of simulation distortion and single monitoring dimension of the traditional device; through the cooperative evaluation of the carbon fixation efficiency, the diffusion retardation coefficient and the structure stability coefficient, the comprehensive repair performance of the basalt-soil mixed system in the carbon fixation, leakage resistance and soil stabilization is comprehensively and objectively reflected, and the evaluation deviation caused by relying on only the single carbon fixation efficiency is overcome.

[0044] The above are preferred embodiments of the application, and do not limit the protection scope of the application, therefore: any equivalent changes made according to the structure, shape, principle of the application should be covered within the protection scope of the application.

Claims

1. A simulation experimental device for basalt-soil remediation of shallow surface CO2 leakage, characterized in that: include: A composite reaction module includes a reaction chamber, in which a temperature control device and a humidity control device are provided, and multiple dispersed injection holes are provided at the bottom of the reaction chamber; The CO2 leakage simulation module includes a CO2 gas source connected to the distributed injection port, and a mass flow controller disposed at the outlet of the CO2 gas source. The monitoring module includes a CO2 gas concentration sensor and multiple resistivity sensors. The CO2 gas concentration sensor is located at the top of the reaction chamber, and the multiple resistivity sensors are arranged at intervals along the height direction of the reaction chamber on the inner sidewall of the reaction chamber. Multiple sampling ports are arranged at intervals along the height direction on the sidewall of the reaction chamber, and the number of sampling ports is the same as that of the resistivity sensors and the position is at the same height.

2. The basalt-soil remediation simulation experimental device for shallow surface CO2 leakage according to claim 1, characterized in that: The dispersed injection holes are arranged in an array at the bottom of the reaction chamber, and a porous medium is laid on the bottom of the reaction chamber above the dispersed injection holes.

3. The basalt-soil remediation simulation experimental device for shallow surface CO2 leakage according to claim 1, characterized in that: The temperature control device includes an electric heating layer and a temperature sensor embedded in the inner wall of the reaction chamber.

4. The basalt-soil remediation simulation experimental device for shallow surface CO2 leakage according to claim 1, characterized in that: The humidity control device includes a spray device installed at the top of the reaction chamber, the spray device being connected to a water source, and a humidity sensor.

5. The basalt-soil remediation simulation experimental device for shallow surface CO2 leakage according to claim 1, characterized in that: The top of the reaction chamber is connected to an exhaust pipe, which is equipped with a one-way valve to control the pressure inside the reaction chamber; a gas pressure sensor is installed inside the reaction chamber.

6. The basalt-soil remediation simulation experimental device for shallow surface CO2 leakage according to claim 1, characterized in that: The resistivity sensors are distributed at equal intervals along the height of the reaction chamber, and the sampling ports are distributed at equal intervals along the height of the reaction chamber.

7. The basalt-soil remediation simulation experimental device for shallow surface CO2 leakage according to claim 1, characterized in that: It also includes a data acquisition and recording system, which is connected to the monitoring module and is used to record and process the data acquired by the monitoring module.

8. The basalt-soil remediation simulation experimental device for shallow surface CO2 leakage according to claim 1, characterized in that: The reaction chamber is equipped with removable, layered partitions to simulate different geological strata.

9. A simulation experimental method for basalt-soil remediation of shallow surface CO2 leakage, employing the simulation experimental apparatus for basalt-soil remediation of shallow surface CO2 leakage as described in any one of claims 1-8, characterized in that: Includes the following steps: A porous medium is laid at the bottom of the reaction chamber, and then a quartz sand layer and a basalt-soil mixture layer are filled in sequence to the target height and compacted to the target compaction degree. The humidity of the basalt-soil mixture layer is adjusted to the target humidity through a humidity control device, and the temperature gradient of the basalt-soil mixture layer is adjusted to the target temperature gradient through a temperature control device. CO2 is introduced and adjusted to the target pressure, and the constant / pulse leakage rate of CO2 is set through a mass flow controller. Real-time monitoring and recording of CO2 concentration, resistivity, temperature and humidity of the basalt-soil mixed layer in the reaction chamber, and periodic collection of gas samples through the sampling port; After the reaction is completed, the carbon fixation efficiency is calculated based on the CO2 consumption and carbonate production before and after the reaction. The CO2 diffusion rate of the pure soil system, the CO2 diffusion rate of the basalt-soil mixed system, and the CO2 diffusion retardation coefficient are calculated based on the CO2 concentration change. The structural stability coefficient is calculated based on the resistivity before and after the reaction. The remediation effect of the basalt particle-soil mixture system was evaluated by combining carbon fixation efficiency, CO2 diffusion inhibition coefficient and structural stability coefficient.

10. A simulation experimental method for basalt-soil remediation of shallow surface CO2 leakage according to claim 9, characterized in that: The target temperature gradient is 20-60°C, the target pressure is 0.5-2 MPa, and the leakage rate is 0.1-10 mL / min.

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