CN113404538B - System and method for storing carbon dioxide based on coal mine goaf - Google Patents

Abstract

The invention relates to the technical field of carbon dioxide emission reduction, and particularly discloses a system and a method for sealing carbon dioxide based on a coal mine goaf, wherein the system comprises the following steps: a carbon dioxide temporary storage device; the underground closed space is positioned in the caving zone goaf and is used for sealing and storing carbon dioxide, and the underground closed space is formed by surrounding a protective coal pillar, a well field boundary protective coal pillar and a closed roadway in the coal mine goaf; the gas injection device comprises a gas injection pipeline communicated with the carbon dioxide temporary storage device, and the gas injection pipeline sequentially penetrates through the bending subsidence zone and the fracture zone and extends into the underground closed space; at least one monitoring device includes a monitoring conduit extending through the bending dip zone and the fracture zone and into the underground enclosure. The invention can economically, efficiently and massively seal and store a large amount of carbon dioxide, and can be used for pumping and reutilizing the carbon dioxide as a resource when necessary, thereby realizing convenient sealing and subsequent use of the carbon dioxide.

Description

System and method for storing carbon dioxide based on coal mine goaf

Technical Field

The present invention relates to the technical field of carbon dioxide emission reduction, and specifically discloses a system and method for storing carbon dioxide in a coal mine goaf.

Background technique

At present, thermal power plants, coal chemical industry and other carbon dioxide release units have begun to build carbon dioxide capture and storage projects (CCS) and put them into use to achieve the goal of carbon dioxide emission reduction. With years of research and development, the industrial capture of carbon dioxide has matured, but the storage method has not yet achieved a breakthrough. The current methods of carbon dioxide storage are: 1. Geological storage: Geological storage is to use the gaps and accommodation capacity of special strata to store carbon dioxide. One is to inject carbon dioxide into oil and gas wells and use the spatial accommodation capacity of oil and gas wells to store carbon dioxide. With more than 10 years of research on carbon dioxide storage technology, this method is relatively mature. The second is to find geological saline layers, use the solubility of saline water bodies and spatial gaps, and inject carbon dioxide under high pressure to achieve the purpose of storage. This method has limited carbon dioxide storage capacity and is restricted by geological conditions. 2. Marine storage: Inject carbon dioxide into the deep sea. Under seawater pressure conditions, carbon dioxide is stored on the seabed in a form with a density higher than seawater. The depth of marine storage is generally 3,000 meters and 300 atmospheric pressures. 3. Surface chemical storage: React carbon dioxide with calcium oxide or magnesium hydroxide minerals to generate carbonate solid substances. 4. Biological storage: Provide carbon dioxide to plants such as algae or forests, and use the photosynthesis of plants to consume carbon dioxide. However, the above storage methods have problems such as long transportation distance, low efficiency and small scale, and cannot meet the current large-scale industrial storage needs.

Summary of the invention

The main purpose of the present invention is to provide a system and method for storing carbon dioxide based on coal mine goaf, aiming to solve at least one of the above technical problems.

To achieve the above object, the present invention proposes a system for storing carbon dioxide based on a coal mine goaf, wherein the coal mine goaf is located in a caving zone goaf, and a fracture zone and a curved sinking zone are sequentially formed above the caving zone goaf. The system comprises:

Carbon dioxide temporary storage device;

At least one underground enclosed space, located in the caving zone, for storing carbon dioxide, and the underground enclosed space is surrounded by protective coal pillars in the coal mine goaf, protective coal pillars at the boundary of the well field, and enclosed tunnels;

A gas injection device, comprising a gas injection pipeline connected to the carbon dioxide temporary storage device, wherein the gas injection pipeline sequentially penetrates the curved subsidence zone and the fracture zone and extends into the underground confined space;

At least one monitoring device includes a monitoring pipeline that penetrates the curved subsidence zone and the fracture zone and extends into the underground enclosed space.

In addition, the present invention proposes a method for storing carbon dioxide based on a system for storing carbon dioxide in coal mine goafs, comprising the following steps:

Check and create airtight conditions in coal mine goafs;

Determine the location of the gas injection holes and monitoring holes;

According to the locations of the gas injection holes and monitoring holes, drill holes from the surface above the underground confined space to arrange pipelines, install and connect the carbon dioxide temporary storage device, gas injection device and monitoring device;

Injecting carbon dioxide into confined underground spaces.

In addition, the above-mentioned system for storing carbon dioxide based on coal mine goaf of the present invention may also have the following additional technical features.

According to one embodiment of the present invention, the gas injection device also includes a pressure sensor and a concentration sensor arranged in the gas injection pipeline, the monitoring device also includes a pressure sensor and a concentration sensor arranged in the monitoring pipeline, and the system also includes a controller connected to the pressure sensor and the concentration sensor and a remote monitoring device connected to the controller.

According to one embodiment of the present invention, it further includes a power supply device provided on the gas injection device and the monitoring device, and the power supply device is connected to the pressure sensor and the concentration sensor respectively.

According to one embodiment of the present invention, at least two electrically controlled safety valves are arranged in the gas injection pipeline; and at least two check safety valves are arranged in the monitoring pipeline.

According to one embodiment of the present invention, the gas injection pipeline is in communication with a middle area of the underground confined space, and the monitoring pipeline is in communication with a boundary area of the underground confined space.

According to one embodiment of the present invention, after the steps of installing and connecting the carbon dioxide temporary storage device, the gas injection device and the monitoring device, the method further includes:

Cement mortar is poured between the outer walls of the gas injection pipeline and monitoring pipeline and the rock formation to enhance the safety and reliability of the pipeline.

According to one embodiment of the present invention, before the step of injecting carbon dioxide into the underground confined space, the method further includes:

Air is injected into the underground confined space until the underground confined space reaches a preset pressure value. The real-time pressure value of the underground confined space is monitored by a monitoring device. According to the difference between the real-time pressure value and the preset pressure value, it is determined whether the underground confined space meets the sealing conditions.

According to an embodiment of the present invention, determining whether the underground confined space meets the sealing condition according to the magnitude of the real-time pressure value and the preset pressure value includes:

Determine that the real-time pressure value is equal to the preset pressure value, and determine that the underground confined space meets the sealing condition; or

Determine that the real-time pressure value is less than the preset pressure value, determine that the underground enclosed space does not meet the sealing conditions, carry out geological surveys, find and determine the locations of faults and sinkholes that are connected to the surface, and then groutingly seal the faults and sinkholes.

According to one embodiment of the present invention, before the step of determining that the underground confined space meets the closing conditions, the method further includes: determining that the underground confined space area does not belong to a water resource enrichment area;

The steps to determine if an underground confined space meets the conditions for enclosure include:

Make sure the caving zone and the fracture zone are not conductive to the ground surface;

Determine the location of faults and sinkholes that are connected to the surface, and grout the faults and sinkholes;

Reinforce and seal the enclosed tunnels in the coal mine goaf.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention proposes a system and method for storing carbon dioxide based on coal mine goafs, which can economically, efficiently and on a large scale store a large amount of carbon dioxide, and store the carbon dioxide as a resource, which can be extracted and utilized again when necessary, thereby realizing the convenient storage and subsequent use of carbon dioxide.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

FIG1 is a distribution diagram of coal mine goaf areas in one embodiment of the present invention;

FIG2 is a cross-sectional view of an underground confined space in one embodiment of the present invention;

FIG3 is a schematic diagram of a system for storing carbon dioxide in a coal mine goaf according to an embodiment of the present invention;

FIG4 is a diagram showing the distribution of openings in an underground confined space according to an embodiment of the present invention;

FIG5 is a schematic diagram of the structure of a gas injection device in one embodiment of the present invention;

FIG6 is a schematic diagram of the structure of a monitoring device according to an embodiment of the present invention;

FIG7 is a partial enlarged view of FIG6;

FIG. 8 is a schematic diagram of the plugging of a collapse column in one embodiment of the present invention.

The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings.

Detailed ways

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed 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, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

The following describes a system and method for storing carbon dioxide in a coal mine goaf in some embodiments of the present invention with reference to FIGS. 1-8 .

As shown in FIGS. 1-6, an embodiment of the present invention provides a system for storing carbon dioxide based on a coal mine goaf. It should be noted that a coal mine goaf 10 is located in a caving zone 11, and a fracture zone 12 and a curved sinking zone 13 are sequentially formed above the caving zone 11. The system for storing carbon dioxide based on a coal mine goaf includes a carbon dioxide temporary storage device, at least one underground enclosed space 14, a gas injection device 15, and at least one monitoring device 16, wherein the underground enclosed space 14 is located in the caving zone 11, and is used to store carbon dioxide, and the underground enclosed space 14 is composed of a protective coal pillar 10 in the coal mine goaf 10. 1. The field boundary protection coal pillar 102 and the closed tunnel 103 are surrounded. The gas injection device 15 includes a gas injection pipeline 150 connected to the carbon dioxide temporary storage device, so as to inject the carbon dioxide in the carbon dioxide temporary storage device into the underground closed space 14. The gas injection pipeline 150 sequentially penetrates the curved sinking zone 13 and the fracture zone 12 and extends into the underground closed space 14. The monitoring device 16 is used to monitor the concentration and pressure of carbon dioxide sealed in the underground closed space 14. The monitoring device 16 includes a monitoring pipeline 160 that penetrates the curved sinking zone 13 and the fracture zone 12 and extends into the underground closed space 14.

Specifically, the carbon dioxide temporary storage device is arranged at a flat position around the gas injection hole, mainly a pressurized gas storage tank for automobile transportation (it can also be a pressure gas storage tank built of underground concrete). The temporary storage device can store carbon dioxide-rich tail gas emitted by various industries (such as carbon dioxide-rich tail gas emitted during the operation of industrial facilities such as thermal power plants, steel plants and coal chemical industry), preferably power plant flue gas, carbon dioxide tail gas emitted by coal chemical industry, or a mixture of the two, more preferably power plant flue gas, a mixture of power plant flue gas and carbon dioxide tail gas emitted by coal chemical industry, and most preferably power plant flue gas.

In one embodiment of the present invention, referring to FIG. 4 , an air inlet 140 is provided in the middle region of the underground confined space 14 , through holes 141 are provided in the edge regions on both sides of the underground confined space 14 , the air injection pipe 150 is connected to the air inlet 140 , and the monitoring pipe 160 is connected to the through holes 141 .

It is worth mentioning that, in a preferred embodiment, the at least one underground enclosed space 14 is a plurality of underground enclosed spaces, such as 2 to 6 underground enclosed spaces, and the plurality of underground enclosed spaces can be injected with carbon dioxide simultaneously or in turn to improve the treatment efficiency.

Further, in this embodiment, with continued reference to FIGS. 5-7 , the gas injection device 15 also includes a pressure sensor 151 and a concentration sensor 152 disposed in the gas injection pipeline 150, and the monitoring device 16 also includes a pressure sensor 151 and a concentration sensor 152 disposed in the monitoring pipeline 160. The system for sealing carbon dioxide based on coal mine goaf also includes a controller connected to the gas injection pipeline 150 and the pressure sensor 151 and the concentration sensor 152 in the monitoring pipeline 160, and a remote monitoring device connected to the controller. Specifically, the remote monitoring device can be a server, a mobile phone, a computer or other monitoring device for monitoring the pressure value and concentration value of carbon dioxide in the underground confined space 14. The pressure sensor 151 and the concentration sensor 152 can obtain the pressure value and concentration value of carbon dioxide in the underground confined space 14, and transmit the pressure value and concentration value of carbon dioxide to the controller, and the controller transmits the pressure value and concentration value of carbon dioxide to the remote monitoring device, thereby realizing continuous monitoring and regular recording of the pressure value and concentration value of carbon dioxide.

It is worth mentioning that, referring to Figures 5-7, the system for storing carbon dioxide in coal mine goafs also includes a power supply device 17 provided on the gas injection device 15 and the monitoring device 16. The power supply device 17 is respectively connected to the pressure sensor 151 and the concentration sensor 152 in the gas injection pipeline 150 and the monitoring pipeline 160, and the controller for realizing solar power supply.

It should be noted that the power supply device 17 can be solar energy, wind energy, or a power grid, which is not limited in this embodiment.

In addition, referring to Figures 5-7, at least two electrically controlled safety valves 153 are provided at positions corresponding to the curved subsidence zone 13 and the fracture zone 12 in the gas injection pipeline 150, and at least two non-return safety valves 161 are provided at positions corresponding to the curved subsidence zone 13 and the fracture zone 12 in the monitoring pipeline 160. Specifically, in order to prevent the carbon dioxide sealed in the underground confined space 14 from overflowing and ensure the absolute safety of the sealed carbon dioxide, in this embodiment, two electrically controlled safety valves 153 and a non-return safety valve 161 are provided in the gas injection pipeline 150 and the monitoring pipeline 160, respectively, to prevent the sealed carbon dioxide from being ejected. At the same time, considering the stability of the rock structure, double-layer electric-controlled safety valves 153 and double-layer check safety valves 161 are arranged in the curved sinking zone 13 and the fracture zone 12 respectively to ensure that the sealing is dense and reliable. The electric-controlled safety valve 153 and the check safety valve 161 are independent pipeline sections, which are installed in the gas injection pipeline 150 and the monitoring pipeline 160 before drilling the pipeline. They enter the hole with the pipeline as a part of the gas injection pipeline 150 and the monitoring pipeline 160.

It is worth mentioning that the installation positions of the electric control safety valve 153 and the non-return safety valve 161 in the present application are not limited to the positions corresponding to the curved sinking zone 13 and the fracture zone 12, as long as the electric control safety valve 153 and the non-return safety valve 161 are installed in the gas injection pipeline 150 and the monitoring pipeline 160. In this embodiment, a mounting bracket can be set in the gas injection pipeline 150 and the monitoring pipeline 160, and the mounting bracket can be used to fix the pressure sensor 151 and the concentration sensor 152, and the signal and power supply cables connected to the pressure sensor 151 and the concentration sensor 152 are fixed along the inner wall of the gas injection pipeline 150 and the monitoring pipeline 160, wherein the pressure sensor 151 and the concentration sensor 152 are located in the area corresponding to the fracture zone 12 of the gas injection pipeline 150 and the monitoring pipeline 160, and the pressure sensor 151 and the concentration sensor 152 are located below the electric control safety valve 153 or the non-return safety valve 161.

Next, this embodiment describes in detail a method for storing carbon dioxide using a system for storing carbon dioxide in a coal mine goaf, which specifically includes the following steps:

S100: Check and create airtight conditions in coal mine goafs;

First, it is determined that the caving zone 11 and the fracture zone 12 are not connected to the ground surface; specifically, after the coal mine is mined, the caving zone 11, the fracture zone 12, and the curved subsidence zone 13 (referred to as the three zones) will be formed. The fracture zone 12 is the main factor that destroys the sealing condition of the underground confined space. The caving zone 11 and the fracture zone 12 are not connected to the ground surface, which is one of the conditions that affect whether the underground confined space 14 is closed.

The calculation formula for the range of the fracture zone in the coal mine goaf is: The maximum H _{mining height} of underground coal mines is 9m. After substituting the above formula and retaining a certain security factor, theoretical calculations show that the coal mine goaf with a depth of 100m is sealed. Most of China's coal is buried below 200 meters, which shows that there are many coal mines that meet the sealing conditions.

Secondly, it is determined that the underground confined space 14 area does not belong to the water resource enrichment area; specifically, there are water resource enrichment areas such as rivers and lakes above the coal mine goaf, which show large and continuous water inflow during coal production. After the coal mine goaf is closed, there is a large amount of groundwater, which is not suitable as a carbon dioxide confinement area and should be excluded.

Furthermore, the positions of the faults and collapse columns 18 connected to the surface are determined, and the faults and collapse columns 18 are sealed by grouting. Specifically, the faults and collapse columns 18 connected to the surface will affect the closure of the underground enclosed space. In order to solve this problem, this embodiment conducts a geological survey, obtains geological structure information, determines the positions of the faults and collapse columns 18 connected to the surface, and uses grouting to seal them to achieve full closure.

It should be noted that the blocking methods of the fault and the collapse column 18 are the same. As shown in FIG8 , this embodiment is described in detail with reference to the blocking of the collapse column 18. The method is as follows:

1. Prepare grouting materials and transport them using a slurry truck 19. The slurry is mainly made of 32.5 ordinary Portland cement, supplemented by waterproof materials and pore sols, and is mixed evenly in a certain proportion;

2. Drill engineering holes (aperture diameter) at the bottom, middle and top of the collapse column 18. ), arranging a grouting conduit 20;

3. Grouting is performed in order from bottom to top to ensure that the collapse column 18 is closed at multiple levels to increase the safety factor. The grouting pump station 21 is used to transport the slurry on the slurry truck 19 to the grouting conduit 20. The grouting pressure is controlled at 2MPa each time. When the pressure exceeds this, the grouting is stopped, and the grouting volume is calculated to estimate the size of the closed space.

Finally, the closed tunnel 103 in the coal mine goaf is reinforced and sealed. Specifically, although the closed tunnel 103 has been sealed with masonry mortar, it is a weak point and is reinforced and sealed again to ensure the closure of the underground confined space.

S200: Determine the positions of the gas injection hole 22 and the monitoring hole 23. In this embodiment, the positions of the gas injection hole 22 and the monitoring hole 23 can be determined based on the existing geological plan verified by production during the coal mining process;

S300: According to the positions of the gas injection holes 22 and the monitoring holes 23, drilling holes downward from the surface above the underground confined space 14 to arrange pipelines, and installing and connecting the carbon dioxide temporary storage device, the gas injection device 15 and the monitoring device 16;

In this embodiment, in combination with the diameter of the gas injection pipe 150, the gas injection hole 22 can select a conventional borehole diameter of 168 mm, and the gas injection pipe 150 can select a 100 mm diameter alloy pipe to meet the requirements of gas injection volume and gas injection pressure. Cement slurry is filled between the outer wall of the gas injection pipe 150 and the rock wall of the gas injection hole 22 to ensure that the pipeline is dense and pressure-resistant, and to enhance the reliability and safety of the pipeline.

Accordingly, in combination with the purpose of the monitoring hole 23, the monitoring hole 23 is selected with a conventional drilling diameter of 110 mm, and the monitoring pipe 160 is selected with a 76 mm diameter alloy pipe to meet the monitoring and safety requirements. The outer wall of the monitoring pipe 160 and the monitoring hole 23 are filled with cement slurry to ensure that the pipeline is dense and pressure-resistant, and to enhance the reliability and safety of the pipeline.

S400: Perform a sealing test on the underground confined space 14;

Inject air into the underground confined space 14 until the underground confined space 14 reaches a preset pressure value, such as 5MPa. The real-time pressure value of the underground confined space 14 is monitored by the monitoring device 16. The test can be continued for 10 days. According to the difference between the real-time pressure value and the preset pressure value, it is determined whether the underground confined space 14 meets the sealing condition. Specifically, when the real-time pressure value is equal to the preset pressure value, it can be determined that the underground confined space 14 meets the sealing condition and the test is qualified. The switch of the electric control safety valve 153 is opened to release the gas.

Accordingly, when the real-time pressure value is less than the preset pressure value, it is determined that the underground enclosed space 14 does not meet the sealing conditions, and geological survey is conducted again to find and determine the leakage and pressure relief location, and then grouting is performed to seal the leakage and pressure relief location.

S500: Injecting carbon dioxide into the underground confined space 14.

In this embodiment, according to the geological data of the production process, as shown in Table 1, the annual temperature of the underground confined space 14 is 5°C (subject to the measured data), and in this case, the pressure required for carbon dioxide to become liquid is 3.96MPa. The carbon dioxide temporary storage device is continuously injected into the underground confined space 14 through the gas injection pipeline using a pressure pump, and the pressure value of the underground confined space 14 is monitored in real time. When it reaches 3.96MPa, the underground confined space 14 is filled.

Table 1 Liquid carbon dioxide temperature and pressure comparison table

temperature pressure 10 4.50 9 4.39 8 4.28 7 4.18 6 4.07 5 3.96 4 3.87 3 3.77 2 3.67 1 3.58 0 3.48 -1 3.39 -2 3.30 -3 3.22 -4 3.13 -5 3.05 -6 2.96 -7 2.88 -8 2.80 -9 2.72 -10 2.65

S600: Continue to monitor the pressure and concentration of carbon dioxide in the underground confined space 14.

In this embodiment, the pressure value and concentration value of carbon dioxide are monitored in real time by the monitoring device 16, and the collected pressure value and concentration value are sent to the monitoring equipment at regular intervals, thereby achieving real-time monitoring and regular reporting of the pressure value and concentration value of carbon dioxide.

When it is necessary to extract and utilize carbon dioxide in the future, the electric-controlled safety valve 153 is turned on to slowly open the gas injection hole and connect to the carbon dioxide collection tank on the surface, so that the extraction and utilization of carbon dioxide can be realized.

The embodiments of the present disclosure are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, a person skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims (7)

1. The method for sealing carbon dioxide is characterized by adopting a system for sealing carbon dioxide based on a coal mine goaf, wherein the coal mine goaf is positioned on a caving zone, a fissure zone and a bending sinking zone are sequentially formed above the caving zone, the depth of the coal mine goaf is below 100m, and the system comprises: a carbon dioxide temporary storage device; the underground closed space is positioned on the falling zone and used for sealing and storing carbon dioxide, and is formed by surrounding a protective coal pillar, a well field boundary protective coal pillar and a closed roadway in the coal mine goaf; the gas injection device comprises a gas injection pipeline communicated with the carbon dioxide temporary storage device, and the gas injection pipeline sequentially penetrates through the bending subsidence zone and the fracture zone and extends into the underground closed space; at least one monitoring device comprising a monitoring conduit extending through the curved dip zone and the fracture zone and into the underground enclosure;

the method comprises the following steps:

checking and creating a closed condition of a coal mine goaf;

Determining the positions of the gas injection hole and the monitoring hole;

According to the positions of the gas injection holes and the monitoring holes, arranging pipelines from the surface above the underground closed space downwards, installing and connecting a carbon dioxide temporary storage device, a gas injection device and a monitoring device, injecting air into the underground closed space until the underground closed space reaches a preset pressure value, monitoring the real-time pressure value of the underground closed space by the monitoring device, and determining whether the underground closed space meets a sealing condition according to the real-time pressure value and the preset pressure value;

Determining that the real-time pressure value is equal to a preset pressure value, and determining that the underground closed space meets the sealing condition; or determining that the real-time pressure value is smaller than a preset pressure value, determining that the underground closed space does not meet the sealing condition, supplementing geological investigation, searching and determining the positions of faults and collapse columns conducted with the ground surface, and grouting and plugging the faults and the collapse columns, wherein the plugging methods of the faults and the collapse columns are the same;

The plugging method of the collapse column comprises the following steps: preparing grouting materials, conveying the grouting materials by using a slurry vehicle, and uniformly stirring the slurry by taking 32.5 ordinary Portland cement as a main material, and adding a waterproof material and a pore sol agent according to a certain proportion; drilling engineering drilling holes with the diameter phi of 42mm at the bottom, the middle and the top of the collapse column, and arranging grouting guide pipelines; respectively grouting according to the sequence from bottom to top to ensure multi-level sealing of the collapse column, conveying the slurry on the slurry car into a grouting guide pipe by using a grouting pump station, controlling the grouting pressure at 2MPa each time, stopping grouting when the grouting pressure exceeds the grouting pressure, calculating the grouting volume, and estimating the size of a sealing space;

carbon dioxide is injected into the underground enclosed space.

2. The method of sequestering carbon dioxide of claim 1, further comprising, prior to the step of installing and connecting the carbon dioxide temporary storage device, the gas injection device, and the monitoring device:

And (3) cement mortar is poured between the outer wall of the gas injection pipeline and the monitoring pipeline and the rock stratum.

3. The method of sequestering carbon dioxide of claim 1, further comprising, prior to the step of determining that the subterranean enclosed space meets the sequestration condition:

determining that the underground closed space area does not belong to the water resource enrichment area;

The step of determining that the underground enclosed space meets the enclosed condition comprises the following steps:

determining that the landing zone and the fracture zone are not conducted with the ground surface;

determining the positions of faults and collapse columns which are conducted with the ground surface, and grouting and plugging the faults and the collapse columns;

and reinforcing and sealing the closed roadway of the coal mine goaf.

4. The method of sequestering carbon dioxide of claim 1, wherein the gas injection device further comprises a pressure sensor and a concentration sensor disposed within the gas injection conduit, the monitoring device further comprises a pressure sensor and a concentration sensor disposed within the monitoring conduit, and the system further comprises a controller coupled to the pressure sensor and the concentration sensor and a remote monitoring device coupled to the controller.

5. The method of sequestering carbon dioxide of claim 4, further comprising providing power supply means on said gas injection means and monitoring means, said power supply means being connected to a pressure sensor and a concentration sensor, respectively.

6. The method of sequestering carbon dioxide of claim 4, wherein at least two electronically controlled safety valves are disposed in said gas injection conduit and at least two non-return safety valves are disposed in said monitoring conduit.

7. The method of sequestering carbon dioxide of claim 1, wherein said gas injection conduit communicates with a central region of said underground enclosure and said monitoring conduit communicates with a border region of said underground enclosure.