A method for reconstructing carbon storage space in abandoned main roadway by filling and CO2 sealing

Abstract

The application discloses a method for reconstructing and storing CO2 by filling the carbon storage space in abandoned large roadway. The method comprises the following steps: surveying the surrounding rock of the roadway by using geophysical exploration technology, reinforcing and supporting the unstable area of the surrounding pressure bearing by using anchor net (cable), preparing the filling support template in advance according to the width and height of the large roadway section, placing the filling support template in the large roadway, injecting the filling slurry around the filling support template, and simultaneously injecting supercritical carbon dioxide into the filling slurry and the roadway. The method realizes the redevelopment and utilization of the space of the abandoned large roadway, simultaneously injects the supercritical carbon dioxide into the roadway section fissure of the abandoned large roadway during the grouting plugging, and injects the supercritical carbon dioxide into the internal space of the roadway, so that a new scheme for storing carbon dioxide is provided, and the method has a high market prospect and practical utilization value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of emission reduction, carbon reduction and waste space recycling, and particularly relates to a method for filling and reconstructing carbon storage space in a waste main roadway and CO2 storage. BACKGROUND

[0002] At present, while controlling energy consumption and green development, carbon capture, utilization and storage technology has developed rapidly as a large-scale greenhouse gas emission reduction technology. Based on the basic national conditions of more coal and less oil in China, the huge goaf formed after a large amount of coal resources mining becomes a natural space for carbon emission and storage, and the space advantage of the main roadway with small surrounding rock damage and large supporting strength is more prominent. Therefore, it is urgent to seek a technology for recycling the waste main roadway space and simultaneously realizing the storage of carbon dioxide.

[0003] At present, there are many existing technologies related to the utilization of waste mine main roadway. Chinese patent CN107780965A provides a method for storing waste concrete and storing carbon dioxide in a new waste mine, which fills waste concrete into the goaf and then stores carbon dioxide, effectively realizing carbon storage, but the goaf is not fully utilized. Chinese patent CN112879036A provides a survey, detection and reinforcement method for recycling waste mine main roadway, which provides an evaluation method for the utilization of waste mine main roadway. However, the filling and utilization of the main roadway has a high cost, and carbon dioxide storage is not maximized.

[0004] In summary, it is urgent to find a method for filling and reconstructing carbon dioxide storage space in a waste main roadway to realize the simultaneous storage of carbon dioxide in a waste main roadway space, greatly improving the engineering efficiency and having a wide market prospect and practical utilization value. SUMMARY

[0005] In view of the defects in the above-mentioned existing technologies, the purpose of the present application is to provide a method for filling and reconstructing carbon storage space in a waste main roadway and CO2 storage, which realizes the redevelopment and utilization of the waste main roadway space, grouts and plugs the roadway cross section fissure while injecting supercritical carbon dioxide, and injects supercritical carbon dioxide into the internal space of the roadway. This method realizes the simultaneous use of roadway reinforcement, carbon dioxide chemical storage and carbon dioxide physical storage, provides a new storage scheme for carbon dioxide storage, and greatly improves the engineering efficiency.

[0006] The present application provides a method for filling and reconstructing carbon storage space in a waste main roadway and CO2 storage, comprising the following steps:

[0007] (1) Surveying the surrounding rock of the roadway, analyzing the lithology condition, surrounding rock density and internal fissure and cavity condition of the roadway;

[0008] (2) The part with unstable confining pressure bearing characteristics and obvious damage is reinforced by anchor net (cable) to ensure the stable operation of the main roadway;

[0009] (3) The filling support template is customized according to the width and height of the main roadway section, and the distance between the template and the roadway top, two sides and floor is 50-80 cm;

[0010] (4) The filling wall is constructed at one end of the main roadway, and the thickness of the filling wall needs to reach 50-60 cm to ensure that the one end of the roadway is completely sealed and does not leak gas;

[0011] (5) The filling support template prepared in step (3) is placed inside the main roadway, spliced according to the shape of the roadway, arranged along the filling wall, and temporarily fixed by anchor rod and anchor cable;

[0012] (6) The filling slurry is injected into the gap between the support template and the main roadway along the filling pipeline, forming a 20 cm thick filling thickness around the roadway; supercritical carbon dioxide is injected into the filling slurry between the support template and the main roadway, and the supercritical carbon dioxide and the slurry are fully reacted for 3-5 h to make the slurry solidify to a support strength of 1-2 MPa, and the injection is stopped;

[0013] (7) After the filling slurry and supercritical carbon dioxide are fully reacted and solidified, the filling support template is removed, and a second filling wall is constructed at an interval of 30-40 m; a closed space is formed between the two filling walls and the solidified slurry;

[0014] (8) A gas injection hole is reserved on the second filling wall, and a gas injection pipe inside the main roadway passes through the hole into the closed space formed by the two filling walls, and supercritical carbon dioxide is injected into the closed space of the two filling walls; when the injection pressure of supercritical carbon dioxide is 1-1.5 MPa and the concentration inside the closed space reaches more than 5000 ppm, the injection is stopped, and the gas injection hole on the second filling wall is closed;

[0015] (9) A filling support template is built on the other side of the second filling wall, and a closed space is continued to be constructed relying on the support template, and steps (5)-(8) are repeated, filling slurry and supercritical carbon dioxide are injected outside the support template, and supercritical carbon dioxide is injected into the closed space of the two filling walls;

[0016] (10) When the space filling and storage of the main roadway is completed to the tail of the roadway, an end filling wall is constructed at the other end of the roadway to seal the space of the roadway.

[0017] Preferably, in step (1), the process of surveying the surrounding rock of the roadway is as follows: on the premise of knowing the location of the abandoned main roadway, the propagation law of artificial seismic wave in different elastic strata is used to explore the bearing characteristics, damage depth and crack characteristics of the surrounding rock of the roadway.

[0018] Preferably, the step (2) is to identify the surrounding rock of the waste roadway bearing characteristics instability, more obvious destruction is through step (1) using geophysical exploration technology to survey the roadway after comprehensive evaluation.

[0019] Preferably, the step (2) is to identify the surrounding rock of the waste roadway bearing characteristics instability, more obvious destruction is through step (1) using geophysical exploration technology to survey the roadway after comprehensive evaluation.

[0020] Preferably, the step (3) is to fill the support template, which is forged in advance according to the width and height of the roadway cross section, and is easy to disassemble and assemble by using steel plate and connecting buckle.

[0021] Preferably, the step (6) is to fill the slurry, which is composed of water, cement, alkali residue, sand and additive agent in proportion; the proportion of alkali residue and sand is 5:2-5:4, the cement is added according to 10-20% of the total mass of the three solid raw materials (cement, alkali residue and sand), the additive agent is mainly a composite activator prepared by mixing CaO and CaSO4 in a ratio of 1:1, the additive agent accounts for 1%-1.5% of the total mass of the solid raw materials, and water is added to prepare a slurry with a mass concentration of 74%-80%.

[0022] Preferably, the alkali residue is a waste residue mainly composed of CaCO3, CaSO4 and CaCl2 calcium salt, wherein the mass fraction of CaCO3 in the total alkali residue is 40%-70%, the prepared slurry is alkaline, and the pH value is 9-11; after supercritical carbon dioxide is injected, it fully reacts with CaCO3, absorbs a large amount of carbon dioxide, and realizes the purpose of chemical sequestration.

[0023] Preferably, the supercritical carbon dioxide is converted by a surface carbon dioxide collector and a carbon dioxide converter, and is pumped to the underground roadway through a connecting pipeline.

[0024] The beneficial effects of the present application are:

[0025] The application surveys the roadway surrounding rock through geophysical exploration technology, and reinforces and supports the unstable area of surrounding pressure bearing through anchor net (cable); according to the width and height of the large roadway cross section, a filling support template is prepared in advance, placed in the large roadway, filling slurry is injected into the gap between the support template and the large roadway along the filling pipeline, then supercritical carbon dioxide is injected into the filling slurry to make it fully react with the slurry; then supercritical carbon dioxide is injected into the sealed space formed between the two filling walls and the solidified slurry, realizing the synchronous storage of carbon dioxide. The method can realize the reinforcement and utilization of abandoned large roadway, the synchronous implementation of carbon dioxide chemical storage and carbon dioxide physical storage, provides a new scheme for carbon dioxide storage, and has high market prospect and practical utilization value. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The device schematic diagram for filling and reconstructing carbon storage space in abandoned large roadway-CO2 storage;

[0027] Figure 2 The perspective view of constructing a filling wall at one end of the abandoned large roadway;

[0028] Figure 3 The perspective view of synchronous carbon dioxide storage of the first stage space filling in the abandoned large roadway;

[0029] Figure 4 The perspective view of synchronous carbon dioxide storage of the Nth stage space filling in the abandoned large roadway;

[0030] Figure 5 The perspective view of constructing and filling of the N+1th stage roadway sealing in the abandoned large roadway;

[0031] Figure 6 The perspective view of the large roadway support template.

[0032] In the figure, 1, anchor cable, 2, anchor rod, 3, roadway surrounding rock, 4, support template four around gas injection pipe, 5, surrounding rock fracture zone, 6, support template, 7, large roadway internal gas injection pipe, 8, large roadway, 8.1, one end of the large roadway, 8.2, the other end of the large roadway, 9, filling wall, 10, supercritical carbon dioxide. DETAILED DESCRIPTION

[0033] In order to make the advantages, technical solutions of the present application more clear and definite, the following will make further clear and complete description of the present work combined with the drawings; the following examples are intended to illustrate and explain the present application, and do not limit the scope of the present application.

[0034] As Figures 1-6As shown, a device for carbon storage space filling and reconstruction-CO2 sequestration in an abandoned main roadway includes: anchor cable 1, anchor rod 2, surrounding rock 3, gas injection pipes around the support template 4, surrounding rock fracture zone 5, support template 6, gas injection pipe inside the main roadway 7, main roadway 8, and filling wall 9.

[0035] Among them, anchor cable 1 and anchor rod 2 are fixed to the surrounding rock 3 and the fractured rock zone 5 of the roadway, and the support formwork 6 is temporarily fixed to anchor cable 1 and anchor rod 2.

[0036] like Figure 3 As shown, the filling support template is forged in advance according to the width and height of the main roadway cross-section. It is assembled from steel plates and connecting buckles, making it easy to disassemble and assemble. The structure of the filling support template is: the upper part is arched, and the lower part is square, consisting of two vertical plates, one ring plate, and a bottom horizontal plate. The length of the filling support template in the roadway is 30-40m. The support template 6 is a bent and overlapping steel plate, with a distance of 50cm-80cm from the roadway cross-section in each of the four directions (up, down, left, and right), and is connected to the inside of the roadway by anchor bolts and cables.

[0037] Air injection pipes 4 are arranged around the perimeter of the support formwork 6. After the filling grout is injected, air is injected through these pipes (e.g., ...). Figure 3 (As shown). After the air injection is completed, the support formwork 6 is removed, and the second filling wall is constructed. An air injection hole is pre-drilled in the second filling wall. The air injection pipe 7 inside the main roadway passes through this hole and enters the sealed space formed by the two filling walls. After the sealed space is constructed, air is injected through the air injection pipe 7 inside the main roadway (as shown). Figure 4 (As shown). Example

[0038] A mine located in Taiyuan City, Shanxi Province, was initially constructed in March 1991. Its mining license expired at the end of 2013 and was not renewed, leading to its closure. The mine's surface elevation is -300m. The main haulage roadways, track roadways, and return air roadways are over 5km long, with a height and width of approximately 5m. The roadways are surrounded by solid rock strata, unaffected by mining disturbance. The roadways are supported by a combination of I-beams and concrete, and the roadway walls are relatively intact, with only a few areas showing severe deformation. There are no major faults, folds, or other significant geological structures within 500m of the roadways. The three roadways are currently unused and considered abandoned space. A thermal power plant is located 1km away from the mine, emitting 2,888,000 tons of carbon dioxide annually, incurring tens of millions of yuan in carbon tax. In light of the above, this invention can effectively help store the CO2 from the nearby power plant in the abandoned roadways of the closed mine. The implementation process will be further explained in detail below with reference to the accompanying drawings. The specific implementation steps are as follows:

[0039] Step one: First, use geophysical exploration technology to survey the abandoned track roadway 3 and the surrounding rock fracture zone 5 of the closed mine, and analyze the surrounding rock characteristics and fracture development degree of the abandoned track roadway.

[0040] Step two: Circle the area with serious bearing capacity and damage in the surrounding rock 3 of the roadway, and use anchor cable 1 and anchor rod 2 to reinforce the support of the roadway, and use concrete to seal the intersection of track roadway connecting roadway, chamber and other cross sections.

[0041] Step three: Build a filling wall 9 at one end 8.1 of the roadway 8, the thickness of the filling wall 9 needs to reach about 50 cm, and ensure that there is no air leakage.

[0042] Step four: According to the section of the roadway 8, bake the filling support template 6;

[0043] Step five: Place the forged filling template 6 inside the roadway 8, splice according to the shape of the roadway, the distance from the top, both sides and the floor of the roadway is 50 cm (reserve 50 cm space because the roadway around needs to be grouted and sealed, the roadway not only has cracks in the roof and both sides, but also in the floor), the spliced filling template 6 is temporarily supported by anchor cable 1 and anchor rod 2;

[0044] Step six: The CO2 discharged from the power plant is changed into supercritical CO2 by the ground carbon dioxide collector and converter, and pumped to the underground roadway through the connecting pipeline.

[0045] Step seven: Inject the filling slurry into the pores between the support template 6 and the roadway 8, and form a 50 cm thick filling thickness around the roadway;

[0046] Step eight: Lay the support template around the support template 4, inject supercritical carbon dioxide into the filling slurry through the support template around the support template 4, and fully react the supercritical carbon dioxide with the slurry for 3-5 hours to make the slurry solidify to a support strength of 1-2 MPa, and stop injection;

[0047] Step nine: After the filling slurry around the support template 6 fully solidifies with supercritical carbon dioxide, remove the filling support template 6, and build a second filling wall 9 at an interval of 30-40 m;

[0048] Step ten: Arrange the internal gas injection pipe 7 through the gas injection hole reserved by the second filling wall, inject supercritical carbon dioxide into the sealed space of the two filling walls along the internal gas injection pipe 7 of the roadway, stop injection when the supercritical carbon dioxide injection pressure is 1 MPa-1.5 MPa and the CO2 concentration in the sealed space reaches 5000 ppm or more, remove the internal gas injection hole 7, and seal the filling wall.

[0049] Step eleven: build the filling support template 6 on the other side of the second filling wall 9, continue to build the sealed space relying on the support template, repeat steps four to ten, inject filling slurry and supercritical carbon dioxide outside the support template 6, and inject supercritical carbon dioxide in the sealed space of the two filling walls 9;

[0050] Step twelve: when the space of the main roadway 8 is gradually filled and sealed to the other end 8.2 of the roadway, build the last filling wall 9 at the other end 8.2 of the main roadway, inject supercritical carbon dioxide into the interior thereof, and seal the space of the roadway.

[0051] The above describes the preferred embodiments of the present application. It should be noted that any improvement and modification of the above described implementation method without departing from the technical essence and principles of the present application shall fall within the protection scope of the technical solution of the present application.

Claims

1. A method of carbon storage space filling reconfiguration-CO2 sequestration in abandoned main roadway, characterized in that The method comprises the following steps: (1) surveying the roadway surrounding rock, analyzing the roadway surrounding rock lithology condition, surrounding rock density and the crack cavity condition inside the roadway; (2) using anchor net or anchor cable reinforcement support for the part with unstable bearing characteristics and obvious damage, so as to ensure the stable operation of the main roadway; (3) according to the width and height of the main roadway section, a filling support template is customized, and the distance between the template and the roadway top, two sides and floor is 50cm-80cm; (4) a filling wall is built at one end of the main roadway, and the thickness of the filling wall needs to reach 50cm-60cm, so as to ensure that one end of the roadway is completely sealed and does not leak gas; (5) the filling support template prepared in step (3) is placed in the main roadway, is spliced according to the shape of the roadway and is arranged closely to the filling wall, and the spliced filling support template is temporarily fixed through anchor rods and anchor cables; (6) the filling slurry is injected into the gap between the support template and the main roadway along the filling pipeline, a filling thickness of 50cm-80cm is formed around the roadway, supercritical carbon dioxide is injected into the filling slurry between the support template and the main roadway, the supercritical carbon dioxide and the slurry are fully reacted for 3-5h, the slurry is solidified to reach a supporting strength of 1-2MPa, and the injection is stopped; (7) after the filling slurry and the supercritical carbon dioxide are fully reacted and solidified, the filling support template is disassembled, a second filling wall is built at intervals of 30-40m; (8) supercritical carbon dioxide is injected into the sealed space between the two filling walls through the gas injection hole reserved by the second filling wall, the injection is stopped when the supercritical carbon dioxide injection pressure is 1MPa-1.5MPa and the CO2 concentration in the sealed space reaches more than 5000ppm, and the gas injection hole is sealed; (9) a filling support template is built on the other side of the second filling wall, a sealed space is continuously built relying on the support template, steps (5)-(8) are repeated, the filling slurry and the supercritical carbon dioxide are injected outside the support template, and the supercritical carbon dioxide is injected into the sealed space between the two filling walls; (10) when the main roadway space is filled and stored to the tail of the roadway, a terminal filling wall is built at the other end of the roadway, the space of the roadway is sealed, and supercritical carbon dioxide is injected into the space.

2. A method of carbon storage space filling reconstruction-CO2 sequestration in abandoned main roadway according to claim 1, characterized in that: In the step (1), the process of surveying the roadway surrounding rock is as follows: on the premise of knowing the position of the abandoned main roadway, the bearing characteristics, damage depth and crack characteristics of the roadway surrounding rock are explored by using the propagation law of artificial seismic waves in different elastic strata.

3. A method of carbon storage space filling and reconstruction-CO2 sequestration in abandoned main roadway according to claim 1, characterized in that: In the step (2), the identification of the unstable bearing characteristics and obvious damage of the surrounding rock of the abandoned main roadway is a comprehensive evaluation after the survey of the roadway by using the geophysical exploration technology in the step (1).

4. A method of carbon storage space filling reconstruction-CO2 sequestration in abandoned main roadway according to claim 3, characterized in that: In the step (2), the unstable area of the main roadway is reinforced by using anchor net or anchor cable, and the MSGLW-500 / 22 type resin anchor rod with a specification of Φ22x2400mm and a design anchoring force of ≥190kN / root and an interval of 600x600mm is used; and the Φ22x8000mm anchor cable with a design anchoring force of ≥240kN / root and an interval of 1500x1800mm is used.

5. A method of carbon storage space filling and reconfiguration-CO2 sequestration in abandoned main roadway according to claim 1, characterized in that: The filling support template in step (3) is forged in advance according to the width and height of the large roadway section, and is spliced by steel plates and connecting buckles; the structure of the filling support template is that the upper part is arched, and the lower part is square, that is, the filling support template is combined by two vertical plates, one annular plate and a bottom horizontal plate, and the length of the filling support template in the roadway is 30-40 m.

6. A method of carbon storage space filling and reconfiguration-CO2 sequestration in abandoned roadways according to claim 1, characterized by: The filling slurry in step (6) is combined by water, cement, alkali residue, sand and additive agent in proportion; the proportion of the alkali residue and the sand is 5:2-5:4, the cement is added according to 10-20% of the mass of the three solid raw materials, the additive agent is mainly a composite activator prepared by mixing CaO and CaSO4 at a ratio of 1:1, the additive agent accounts for 1-1.5% of the total mass of the solid raw materials, and water is added to prepare a slurry with a mass concentration of 74-80%.

7. A method of carbon storage space filling reconstruction-CO2 sequestration in abandoned main roadway according to claim 6, characterized in that: The alkali residue is a waste residue composed of CaCO3, CaSO4 and CaCl2 calcium salt, wherein CaCO3 accounts for 40-70% of the total mass of the alkali residue; the prepared slurry is alkaline, and the pH value is 9-11; after the supercritical carbon dioxide is injected, the supercritical carbon dioxide fully reacts with CaCO3 to absorb a large amount of carbon dioxide, thereby achieving the purpose of chemical sequestration.

8. A method of carbon storage space filling and reconfiguration-CO2 sequestration in abandoned main roadway according to claim 1, characterized in that: The supercritical carbon dioxide is converted by a carbon dioxide converter through a carbon dioxide collector on the ground surface, and is pumped to the underground large roadway through a connecting pipeline.

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