A method and structure for constructing a liquid CO2 storage reservoir based on artificial filling dam

Abstract

The present invention relates to a method and structure for constructing a liquid CO2 storage reservoir based on an artificial filling dam body. Coal mining is carried out by excavating a branch tunnel between a transport tunnel and a return air tunnel. After the mining is completed, the branch tunnel is filled at intervals to form an artificial filling dam body. After the artificial filling dam body is stable, the unfilled area is subjected to anti-seepage sealing treatment, and then liquid CO2 is injected to construct a storage reservoir for storing liquid CO2. An innovative synergistic method of CO2 storage and cementation filling to control floor subsidence is proposed, which not only effectively controls surface subsidence, but also is a new liquid CO2 storage method, and also a new path to achieve carbon neutrality in the entire process of coal development and utilization.

Description

Technical Field

[0001] The present invention relates to a method and structure for constructing a liquid CO2 storage reservoir based on an artificial filling dam body, and belongs to a collaborative method for controlling surface subsidence by filling mining and storing liquid CO2. Background Art

[0002] my country's energy source is still mainly coal, and the CO2 produced by the coal industry accounts for a major proportion of the country's total emissions. Carbon emissions have become an issue that needs to be urgently addressed.

[0003] In order to solve the above problems, developing clean energy and improving energy utilization have become the primary tasks. At the same time, the utilization and disposal of CO2 is also a very important part. Most of the coal mining in my country is underground mining. The goaf formed by coal mining provides sufficient space for CO2 disposal. In this context, green coal mining and reasonable disposal of CO2 have become top priorities. Therefore, there is an urgent need for the emergence of a liquid CO2 storage reservoir that can be filled with artificial dams. Summary of the invention

[0004] The present invention provides a method and structure for constructing a liquid CO2 storage reservoir based on an artificial filling dam body, using the space of coal mining as the space of the storage reservoir, making full use of the underground coal mining space, and realizing large-scale sealing of liquid CO2 at the same time.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A method for constructing a liquid CO2 storage reservoir based on an artificial filling dam body specifically comprises the following steps:

[0007] Step S1: Based on the longwall tunnel-by-tunnel cemented filling mining method, the coal in the branch tunnel between the transport tunnel and the return air tunnel is mined, and the coal in the branch tunnel is mined at intervals;

[0008] Step S2: After the interval mining of the branch tunnel is completed in step S1, the two ends of the mined branch tunnel are blocked by the filling dam retaining wall, and the blocked part is subjected to cementing filling operation, and the cementing filling material is filled into the blocked part through the slurry pipeline to form an artificial filling dam;

[0009] Step S3: After the artificial filling dam body is stable, the unmined branch tunnels on both sides of the artificial filling dam body are mined to form a number of cavities for constructing storage reservoirs;

[0010] Step S4: Lay the filling pipelines for constructing the storage reservoir to several cavities located in the underground branch tunnels, embed an anti-seepage material storage tank in each cavity, and connect to a liquid CO2 inlet pipe connected to the filling pipeline, install an anti-seepage material mixing trigger device in the anti-seepage material storage tank, and when the anti-seepage material mixing trigger device detects that CO2 is charged into the anti-seepage material storage tank, the anti-seepage material mixing trigger device is activated to perform anti-seepage treatment on the branch tunnels;

[0011] Step S5: The two ends of each storage tank are blocked by the storage tank retaining wall respectively, so that the cavities of the several storage tanks are formed into a closed space; CO2 is filled into the storage tank through the filling pipeline, and the anti-seepage material mixing trigger device is continuously started to perform anti-seepage treatment on the branch tunnel;

[0012] As a further preferred embodiment of the present invention, the support strength of the storage retaining wall is greater than 7Mpa;

[0013] As a further preferred embodiment of the present invention, the storage retaining wall is made of a single hydraulic support or a retaining wall back plate or a sealing cloth;

[0014] As a further preferred embodiment of the present invention, in step S2, the width of the branch tunnel to be mined is the same as the cross-sectional width of the constructed storage reservoir;

[0015] As a further preferred embodiment of the present invention, in step S2-step S3, between the transport lane and the return air lane, the artificial filling dam body and the storage tank are sequentially arranged at intervals, and the spacing of the branch lanes, the spacing of the formed artificial filling dam bodies and the spacing of the storage tanks are all integer multiples of the cross-sectional width of the branch lanes;

[0016] The method for constructing a liquid CO2 storage reservoir based on an artificial filling dam body is used to construct a liquid CO2 storage reservoir, starting from the ground surface, vertically including the overlying rock layer, the basic roof, the direct roof, the branch tunnel and the bottom plate, and the artificial filling dam body and the storage reservoir are arranged in sequence in the branch tunnel. The two ends of the artificial filling dam body parallel to the cross section are respectively blocked by the filling dam body retaining wall, and the two ends of the storage reservoir parallel to the cross section are respectively blocked by the storage reservoir retaining wall;

[0017] As a further preferred embodiment of the present invention, the angle between the slurry delivery pipeline and the filling dam retaining wall or the storage reservoir retaining wall is 50°-60°.

[0018] Through the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The method for constructing a liquid CO2 storage reservoir based on artificial filling dam provided by the present invention establishes a liquid CO2 storage reservoir in a branch tunnel, which not only prevents and controls surface subsidence after coal mining, but also establishes a large-scale disposal of CO2 solid waste, thus realizing a collaborative technical approach to green mining of coal resources;

[0020] 2. The method of constructing a liquid CO2 storage reservoir based on an artificial filling dam body provided by the present invention has a structure in which the storage reservoir and the artificial filling dam body are both formed by the space mined from coal, thus realizing the reuse of the structure to the greatest extent. The design method is simple and easy, and has high economy and practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0022] Figure 1 is a layout plan of a storage vault in a preferred embodiment provided by the present invention;

[0023] Figure 2 is a cross-sectional view of a structural arrangement formed in a preferred embodiment provided by the present invention;

[0024] Figure 3 It is a work flow chart of the method for constructing a liquid CO2 storage reservoir based on artificial filling dam body provided by the present invention;

[0025] Figure 4 It is a schematic diagram of the structural formation of the storage reservoir provided by the present invention;

[0026] Figure 5 It is a schematic diagram of the structural molding provided by the present invention;

[0027] Figure 6 It is a numerical simulation diagram of basic parameters of the storage reservoir provided by the present invention.

[0028] In the figure: 1 is the artificial filling dam body, 2 is the storage reservoir, 3 is the storage reservoir retaining wall, and 4 is the filling dam body retaining wall. DETAILED DESCRIPTION

[0029] The present invention will now be described in further detail with reference to the accompanying drawings. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "left side", "right side", "upper part", "lower part", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is 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 "first", "second", etc. do not indicate the importance of the components, and therefore cannot be understood as a limitation on the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution by example, and do not limit the scope of protection of the present invention.

[0030] As explained in the background technology, based on the current situation in my country where coal is the main source of energy, the goaf formed after coal mining provides room for CO2 disposal. Therefore, the present application provides a method for constructing a liquid CO2 storage reservoir based on artificial filling dam body, which not only prevents and controls surface subsidence after coal mining, but also establishes large-scale disposal of CO2 solid waste.

[0031] The structure involved in the method provided in this application is mainly composed of two parts, one is the artificial filling dam body, and the other is the storage reservoir. Coal mining is carried out by excavating the branch tunnel between the transport tunnel and the return air tunnel. After the mining is completed, the branch tunnel is filled at intervals to form an artificial filling dam body. After the artificial filling dam body is stable, the unfilled area is sealed for anti-seepage treatment, and then liquid CO2 is injected to build a storage reservoir. An innovative collaborative method of CO2 storage and cementing filling to control floor subsidence is proposed.

[0032] Figure 3-Figure 4 As shown, the specific steps include:

[0033] Step S1: Based on the longwall cemented filling coal mining method, the coal in the branch tunnel between the transport tunnel and the return air tunnel is mined, and the coal in the branch tunnel is mined at intervals. The longwall cemented filling coal mining method based on this application is to adopt its cyclic mining mode. The layout of the working face formed by this process meets the conditions for building a storage depot in this application.

[0034] Step S2: After the interval mining of the branch tunnels is completed in step S1, the two ends of the mined branch tunnels are blocked by the filling dam body retaining wall 4, and the blocking part is subjected to cementing filling operation, and the cementing filling material is filled into the blocking part through the slurry pipeline to form an artificial filling dam body 1. Different from others, this one uses the filling body formed by the cementing filling material to control the top rock layer after the coal resources are mined, and this filling body is the artificial filling dam body of the CO2 storage reservoir. The role of this filling body is an innovation, which not only handles solid waste resources, but also protects the overlying rock layer after the coal is mined from collapsing, while taking into account the artificial filling dam body of the storage reservoir 2. The previous process for forming this artificial filling dam body is the longwall cementing filling coal mining method by lane, that is, the artificial filling dam body is formed by the filling body, the dam body retaining wall and the sealing cloth.

[0035] Step S3: After the artificial filling dam body is stabilized, the unmined branch tunnels on both sides of the artificial filling dam body are mined to form a number of cavities for constructing storage reservoirs.

[0036] Step S4: Lay the filling pipelines for constructing the storage reservoir to several cavities located in the underground branch tunnels, embed an anti-seepage material storage tank in each cavity, and connect to a liquid CO2 inlet pipe connected to the filling pipeline, and install an anti-seepage material mixing trigger device in the anti-seepage material storage tank. When the anti-seepage material mixing trigger device detects that CO2 is charged into the anti-seepage material storage tank, the anti-seepage material mixing trigger device is activated to perform anti-seepage treatment on the branch tunnels.

[0037] Step S5: The two ends of each storage tank are blocked by the storage tank retaining wall 3 respectively, and the cavities of the several storage tanks are formed into a closed space; the support strength of the storage tank retaining wall is greater than 7MPa, because the storage tank retaining wall needs to stably support the internal pressure. At the same time, considering the sealing of the storage tank retaining wall, the storage tank retaining wall is made of a single hydraulic support or a retaining wall backboard or a sealing cloth. CO2 is filled into the storage tank through the filling pipeline, and the anti-seepage material mixing trigger device is continuously started to carry out anti-seepage treatment on the branch lane. Finally, this storage tank is formed. Compared with the current technology, first of all, it utilizes the coal mining space underground, and secondly, it can support the direct top to prevent large deformation, etc., and thirdly, it can realize the large-scale storage of liquid CO2.

[0038] Taking into account the surface subsidence demand of coal mines and the lateral pressure of liquid CO2 storage on the artificial filling dam, it is necessary to study and determine the longwall tunneling spacing, tunneling width, mining spacing, interval filling spacing and CO2 storage cross-sectional dimensions through numerical simulation and theoretical analysis methods; therefore, in step S2, the width of the branch tunnel to be mined is the same as the cross-sectional width of the constructed storage. Between the transport tunnel and the return air tunnel, the artificial filling dam and the storage are arranged in sequence, and the spacing of the branch tunnels, the spacing of the formed artificial filling dams and the spacing of the storage are all integer multiples of the cross-sectional width of the branch tunnel.

[0039] The structure formed by the method of constructing a liquid CO2 storage reservoir based on an artificial filling dam body includes, starting from the ground surface, in the vertical direction, an overlying rock layer, a basic roof, a direct roof, a branch tunnel and a bottom plate, and the artificial filling dam body and the storage reservoir are arranged in sequence at intervals in the branch tunnel. The two ends of the artificial filling dam body parallel to the cross-section are respectively blocked by the filling dam body retaining wall, and the two ends of the storage reservoir parallel to the cross-section are respectively blocked by the storage reservoir retaining wall.

[0040] After the entire structure is formed, since the filling and coal transportation routes are involved during the construction, this application also provides a schematic diagram ( Figure 5 ), one of the figures is the coal transportation route, and the other is the filling route. The cementing filling materials for cementing filling operations are filled into the mined-out branch tunnels through the slurry pipeline in the filling route to form an artificial filling dam body. Here, based on the test results, the angle between the slurry pipeline and the retaining wall of the filling dam body or the retaining wall of the storage reservoir is set to 50°-60°. The limitation of the angle ensures the filling efficiency.

[0041] Example:

[0042] In order to verify the feasibility of the method provided in this application, a coal mine is taken as an example. The designed production capacity of the mine in its mining area is 2.4Mt / a. The current main coal seam is the 2nd coal seam. The designed first mining working face is the CT2101 working face. The working face advancement length is 372m, the face length is 113m, the burial depth is 650m, and the average thickness of the coal seam is 2.95m. The longwall cemented filling mining method is adopted for mining. The mine requires that the surface subsidence be effectively controlled.

[0043] (1) Through numerical simulation and theoretical analysis, the strength of the artificial filling dam required for the working face to control surface subsidence was determined, and it was finally determined that the strength of the artificial filling dam should be greater than 5.216 MPa.

[0044] (2) Based on the strength of the cemented filling required to control surface subsidence and combined with the needs of mine waste disposal, laboratory tests were conducted to further determine the composition and proportion of the cemented filling materials for implementing the cemented filling operation. The final filling ratio was determined to be 80% gangue, 7.5% fly ash, and 12.5% ​​cement.

[0045] (3) Using numerical simulation methods and combining the actual geological and engineering conditions of a coal mine, a simulation study was conducted on the working face that will be mined by longwall mining. Figure 1-Figure 2 As shown, it was finally determined that the width of the filling branch tunnel is 5.4m, the tunnel spacing is 16.2m, the spacing between artificial filling dam bodies after mining is 5.4m, and the cross-section of the storage branch tunnel is 5.4m×2.95m.

[0046] (4) After the CT2101 longwall working face is mined at intervals, the branch tunnels are cemented and filled by setting filling pipelines and filling dam retaining walls to form an artificial filling dam, such as Figure 1 shown.

[0047] (5) After the artificial filling dam body is stable, the unmined branch tunnels on both sides of the artificial filling dam body are mined, and the filling pipeline of the CO2 storage station is laid to the underground branch tunnel. A liquid CO2 inlet pipe, an anti-seepage material storage tank, and an anti-seepage material mixing trigger device are installed inside the storage reservoir. When CO2 is detected to be filled, the anti-seepage material mixing device is triggered to perform anti-seepage treatment on the branch tunnel;

[0048] (6) The two ends of each storage tank are sealed with a storage tank retaining wall to form a closed space, where the storage tank pressure is 7Mpa. The storage tank retaining wall adopts a single hydraulic support, a retaining wall back plate, a sealing cloth, etc. The single support and the back plate are used to ensure the stability of the storage tank retaining wall. Finally, CO2 is filled to build a liquid CO2 storage tank to achieve Figure 6 Storage of liquid CO2 is shown.

[0049] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0050] The meaning of "and / or" described in this application means that the situations where each exists alone or both exist at the same time are included.

[0051] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0052] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for constructing a liquid CO2 storage reservoir based on artificial filling dam, characterized in that: The specific steps include: Step S1: Based on the longwall tunnel-by-tunnel cemented filling mining method, the coal in the branch tunnel between the transport tunnel and the return air tunnel is mined, and the coal in the branch tunnel is mined at intervals; Step S2: After the interval mining of the branch tunnel is completed in step S1, the two ends of the mined branch tunnel are blocked by the filling dam body retaining wall (4), and the blocked part is subjected to cementing filling operation, and the cementing filling material is filled into the blocked part through the slurry pipeline to form an artificial filling dam body (1); Step S3: After the artificial filling dam body (1) is stabilized, the unmined branch tunnels on both sides of the artificial filling dam body (1) are mined to form a plurality of cavities for constructing the storage reservoir (2); Step S4: Lay the filling pipelines for constructing the storage reservoir (2) to several cavities located in the underground branch tunnels, embed an anti-seepage material storage tank in each cavity, and connect to a liquid CO2 inlet pipe connected to the filling pipeline, install an anti-seepage material mixing trigger device in the anti-seepage material storage tank, and when the anti-seepage material mixing trigger device detects that CO2 is charged into the anti-seepage material storage tank, the anti-seepage material mixing trigger device is activated to perform anti-seepage treatment on the branch tunnels; Step S5: The two ends of each storage vault (2) are respectively blocked by the storage vault retaining wall (3), so that the cavities constituting the storage vaults (2) form a closed space; The support strength of the storage reservoir retaining wall (3) is greater than 7MPa; the storage reservoir retaining wall is made of a single hydraulic support or a retaining wall back plate or a sealing cloth; CO2 is filled into the storage reservoir (2) through a filling pipeline, and the anti-seepage material mixing trigger device is continuously started to carry out anti-seepage treatment on the branch tunnel, and finally the storage reservoir is formed; the storage reservoir can be supported directly above the top.

2. The method for constructing a liquid CO2 storage reservoir based on artificial filling dam according to claim 1, characterized in that: In step S2, the width of the branch tunnel to be mined is the same as the cross-sectional width of the constructed storage reservoir (2).

3. The method for constructing a liquid CO2 storage reservoir based on artificial filling dam according to claim 1 is characterized in that: Step S2-Step S3, between the transport lane and the return air lane, the artificial filling dam body (1) and the storage tank (2) are arranged in sequence, and the spacing of the branch lanes, the spacing of the formed artificial filling dam bodies (1) and the spacing of the storage tanks (2) are all integer multiples of the cross-sectional width of the branch lanes.

4. The structure formed by the method for constructing a liquid CO2 storage reservoir based on artificial filling dam body according to claim 1, 2 or 3, characterized in that: Starting from the ground surface, the vertical direction includes the overlying rock layer, the basic roof, the direct roof, the branch tunnel and the bottom plate. The artificial filling dam body (1) and the storage reservoir (2) are arranged in sequence in the branch tunnel. The two ends of the artificial filling dam body (1) parallel to the cross section are respectively blocked by the filling dam body retaining wall (4), and the two ends of the storage reservoir (2) parallel to the cross section are respectively blocked by the storage reservoir retaining wall (3).

5. The structure formed by the method for constructing a liquid CO2 storage reservoir based on artificial filling dam body according to claim 4 is characterized in that: The angle between the slurry delivery pipeline and the filling dam body retaining wall (4) or the storage reservoir retaining wall (3) is 50°-60°.

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