Carbon storage space construction method for negative carbon filling mining

Abstract

The invention discloses a carbon storage space construction method for negative carbon filling mining, which comprises the following steps of: determining the position of a hard and thick rock stratum according to the lithology of overlying strata, determining the height of a gas guide fissure zone based on actual measurement and theoretical calculation, constructing a sealing wall in a to-be-constructed goaf filling area, dividing the goaf filling area into a plurality of spaces arranged at intervals, each space is sealed; gangue filling and grouting are carried out in a caving area above a coal body in a certain area in front of and behind a goaf, and it is ensured that no gas leaks out of a carbon storage space. According to the method, the space after mining is efficiently utilized, safe filling treatment of waste such as gangue is achieved, the storage technology of greenhouse gas such as carbon dioxide is combined, carbon emission is remarkably reduced, and meanwhile resource recycling is promoted.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine grouting filling, and in particular to a method for constructing a carbon storage space for negative carbon filling mining. Background Art

[0002] As a key link in the green mining strategy, the importance of negative carbon filling mining technology is becoming increasingly prominent and has gradually become an important direction for the transformation and upgrading of the coal industry. This not only can efficiently utilize the post-mining space of minerals and realize the safe filling and disposal of waste such as gangue, but also innovatively combines the storage technology of greenhouse gases such as carbon dioxide to significantly reduce carbon emissions. However, the geological structure of different mining areas is significantly different, including geological structures such as rock layer distribution, faults, and folds, which will have a direct impact on the construction of carbon storage space. The complexity of the geological structure increases the difficulty of site selection and design of carbon storage space. In addition, the height and fluidity of groundwater levels are crucial to the stability of carbon storage space. High water levels or highly fluid groundwater may erode carbon storage space and cause carbon dioxide leakage. The existing negative carbon filling methods are relatively single, and the geological conditions of each mine are different. A single filling method cannot be suitable for the actual conditions of mines with different conditions. Therefore, it is of great significance to achieve on-demand filling according to the actual conditions of the mine. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a method for constructing a carbon storage space for negative carbon filling mining. According to the actual conditions of different mines, the layout of the injection system such as the slurry preparation and transportation system and the carbon dioxide pipeline layout is determined to achieve on-demand filling and solve the problems of coal mining gangue treatment and environmental protection.

[0004] Technical solution: A method for constructing carbon storage space for negative carbon filling mining, comprising the following steps:

[0005] S1, through geological exploration, determine the lithology and thickness of the overlying rock layers, and divide the carbon storage space types into high-mining space and dynamic mining space according to the location of the hard and thick rock layers;

[0006] S2, based on geological exploration and theoretical calculation, determine the height of the gas-conducting fracture zone after coal seam backfill mining;

[0007] S3, backfill mining;

[0008] When the carbon storage space type is high mining space, a closed wall is built every 50 to 300 m of advancement of the working face to form a filling section;

[0009] When the carbon storage space type is mining space, gangue filling and grouting are carried out in the collapsed area above the coal body before and after the goaf to seal the carbon storage space to ensure that there is no gas leakage from the carbon storage space;

[0010] S4, injecting carbon dioxide gas into the carbon storage space through pipelines, while monitoring carbon dioxide at the working face and monitoring surface rock movement on the ground to ensure the negative carbon filling effect;

[0011] S5, after the section filling is completed, repeat steps S1 to S4 to fill the next section.

[0012] Furthermore, the carbon storage space types are divided into two categories according to the location of hard and thick rock layers: when the roof of the coal seam is a hard and thick rock layer, the carbon storage space is a high-mining space; when there is a hard and thick rock layer at a certain distance above the coal seam, the carbon storage space is a dynamic mining space.

[0013] Furthermore, the enclosed wall is arranged in parallel with the working surface and has the same length, and both are rectangular spaces.

[0014] Furthermore, in step S3, according to the position of the hard thick rock layer and the height of the gas-conducting fracture zone, a borehole is drilled from the tunnel to the top of the coal body in front and behind the goaf, and slurry is pumped into the borehole by a grouting pump to complete the gangue filling grouting.

[0015] Furthermore, a suitable filling method is used to perform gangue filling and grouting above the coal body in front and behind the goaf;

[0016] The composition of the paste filling material is "gangue + fly ash + cement + quicklime + accelerator". The specific proportion range is: slurry concentration 81-84%, fly ash 40-50%, gangue 35-45%, cement 5-15%, quicklime 0-3%, accelerator 2-4%. After fully mixing, fill it into the goaf.

[0017] Furthermore, in step S3, after the filling of the upper part of the coal body in front and behind the goaf is completed, a closed wall is constructed in the filling area of ​​the goaf every 50 to 300 meters.

[0018] Compared with the prior art, the present invention has the following significant effects:

[0019] 1. The present invention can reduce the difficulty of designing carbon storage space according to the location of hard and thick rock layers, and reduce the impact of geological structure and groundwater on carbon storage space. It can be roughly divided into two situations: the coal seam roof is a hard and thick rock layer and there is a hard and thick rock layer at a certain distance above the coal seam. It has universal applicability.

[0020] 2. The present invention can determine the optimal spatial construction of the injection system according to the lithology of the mine overburden, the height of the gas-conducting fracture zone, etc., which can improve the utilization rate of the space after mineral mining and reduce carbon emissions. It enriches the theoretical system of negative carbon filling technology in coal mines, contributes to the promotion and application of negative carbon filling technology, is of great significance to the realization of more extensive resource utilization and environmental protection, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flow chart of the present invention;

[0022] Figure 2 The schematic diagram of the coal seam roof being filled with hard and thick rock layers;

[0023] Figure 3 This is a schematic diagram showing that there is a hard and thick rock layer filling a certain distance above the coal seam;

[0024] Figure 4 This is the lithology column diagram of the top and bottom plates of the 2303 working face of a certain mine;

[0025] Figure 5 Drilling inspection layout for a mine;

[0026] Figure 6 This is a schematic diagram of filling the goaf area of ​​the 2303 working face of a certain mine. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0028] like Figure 1 As shown, a method for constructing a carbon storage space for negative carbon filling mining includes the following steps:

[0029] Step (a), conducting geological exploration to determine the lithology and thickness of the overlying rock layers, and determining the type of carbon storage space based on the location of the hard and thick rock layers;

[0030] According to the location of hard and thick rock layers, the types of carbon storage space in mines can be divided into two categories: one is that the roof of the coal seam is a hard and thick rock layer, in which case the carbon storage space is the mining height space; the other is that there is a hard and thick rock layer at a certain distance above the coal seam, in which case the carbon storage space is the mining space.

[0031] (A1) The roof of the coal seam is a hard and thick rock layer

[0032] The filling area of ​​the goaf is divided into closed spaces set at a certain distance, so that the goaf is built with closed walls every 50 to 300 meters. Because the space is naturally closed, carbon dioxide and other gases can be directly injected into the carbon storage space through pipelines and filled into the closed space of the goaf. The filling diagram is shown below Figure 2 shown.

[0033] (A2) There is a hard and thick rock layer at a certain distance above the coal seam

[0034] Since there is a collapse area above the goaf, when CO2 gas is injected into the carbon storage space through the pipeline, the gas will leak out, thus losing the meaning of implementing negative carbon filling. Therefore, it is necessary to perform grouting filling above the coal body in a certain area before and after the goaf to ensure that there is no gas leakage. Determine the location of the hard and thick rock layer and the height of the gas-conducting fracture zone, drill a hole from the roadway to the top of the coal body before and after the goaf, and pump slurry into the borehole through a grouting pump to complete the gangue filling grouting.

[0035] Step (b), determining the height of the gas-conducting fracture zone after coal seam backfill mining based on geological exploration and theoretical calculation;

[0036] The determination of the height of the gas-conducting fracture zone mainly includes on-site measurement, theoretical calculation and deductive reasoning.

[0037] Step (c), backfill mining, constructing a closed wall every 50 to 300 m of the working face to form a filling section;

[0038] In the goaf filling area, closed walls are set up every 50 to 300 meters, arranged parallel to the working face with the same length, and are all rectangular spaces to ensure good sealing.

[0039] After the filling of the coal body in front and behind the goaf is completed, the goaf filling area is divided into closed spaces with a certain distance interval, and a closed wall is built every 50 to 300 meters to make the space closed. The purpose is to inject carbon dioxide and other gases into the carbon storage space through pipelines and fill them into the closed space of the goaf. The filling diagram is as follows Figure 3 shown.

[0040] Step (d), according to the type of carbon storage space, determining whether it is necessary to perform gangue filling and grouting to seal the carbon storage space in the collapsed area above the coal body before and after the goaf to ensure that there is no gas leakage from the carbon storage space;

[0041] Gangue grouting filling: Various filling methods can be used to fill the coal body above the front and back of the goaf, such as paste filling, continuous mining and filling, etc. The paste filling material used is composed of "gangue + fly ash + cement + additive A (quicklime) + additive B (accelerator)", and the specific ratio range is: slurry concentration 81-84%, fly ash 40-50%, gangue 35-45%, cement 5-15%, quicklime 0-3%, and accelerator 2-4%. After fully mixing, fill into the goaf.

[0042] Step (e) is to inject carbon dioxide or other gases into the carbon storage space through a pipeline, and at the same time monitor carbon dioxide at the working face and monitor surface rock movement on the ground to ensure the negative carbon filling effect.

[0043] Step (f), after the section filling is completed, repeat steps (a) to (e) to fill the next section.

[0044] The approved production capacity of a mine mining No. 5 coal seam is 10 million tons / year, and the annual production of gangue is 800,000 tons. The gangue discharge site is full, and the disposal of gangue is difficult. The coal thickness of the 2303 working face is 5.30-6.78m, with an average thickness of about 6.0m, an average inclination of 7°, and an average burial depth of 650m. The top and bottom plate columnar diagram of the coal seam is as follows: Figure 3In order to achieve large-scale disposal of gangue, make full use of the post-mining space of the coal mine, reduce carbon emissions, and further subsidence of the surface, the coal mine plans to carry out negative carbon filling on the 2303 working face that has been mined by the longwall mining method. The working face is 245m long, with a forward length of about 2776m and an area of ​​0.68km 2 .

[0045] In conjunction with the carbon storage space construction method for negative carbon filling mining of the present invention, the specific implementation steps are as follows:

[0046] Step 1: Conduct geological exploration to determine the lithology and thickness of the overlying rock layers;

[0047] Depend on Figure 4 It can be seen that the location of the hard and thick rock layer is 52m above the coal seam. According to the location of the hard and thick rock layer, the carbon storage space type is determined as a hard and thick rock layer at a certain distance above the coal seam.

[0048] Step 2, determining the height of the gas-conducting fracture zone based on geological exploration and theoretical calculation;

[0049] According to the technical conditions and equipment conditions on site, when the working face advances to 130m, the drilling rig is used to drill holes in the advanced support section of the working face and conduct peek before and after mining. The drilling arrangement is as follows: Figure 5 As shown. Through drilling and peering, it can be found that the height of the collapse zone of the 2303 fully mechanized caving working face is 20.6m, and the height of the fracture zone is 43.2m;

[0050] Step 3: Carry out backfill mining. A closed wall is built every 150m of the working face, so that each closed space forms a filling section.

[0051] Step 4: According to the type of carbon storage space, it is determined that there is a hard and thick rock layer at a certain distance above the coal seam. Therefore, it is necessary to perform gangue filling and grouting to seal the carbon storage space in the collapsed area above the coal body before and after the goaf to ensure that there is no gas leakage from the carbon storage space;

[0052] Step 5, after confirming that the space is completely sealed, inject carbon dioxide and other gases into the carbon storage space through pipelines, and at the same time monitor carbon dioxide at the working face and monitor surface rock movement on the ground to ensure the negative carbon filling effect.

[0053] Step 6: After the section filling is completed, repeat steps 1 to 5 to fill the next section.

[0054] The mine adopts paste filling coal mining technology. The paste filling material composition is "gangue + fly ash + cement + quicklime + accelerator". The specific ratio range is: slurry concentration 82%, fly ash 45%, gangue 40%, cement 10%, quicklime 2%, accelerator 3%. The density of the prepared paste filling material is about 2.0t / m 3, and then fully mixed and filled into the top of the coal body in front and behind the goaf.

[0055] After the filling of the coal body in front and behind the goaf is completed, a closed wall is built every 150m in the goaf filling area, and all of them are rectangular and the same length as the working face to make the space closed. Carbon dioxide and other gases are injected into the carbon storage space through pipelines and filled into the closed space of the goaf. Figure 6 shown.

[0056] The present invention provides a method for constructing carbon storage space for negative carbon filling mining. By measuring the lithology and the height of the gas-conducting fracture zone, the negative carbon filling carbon storage space is constructed for different situations, thereby avoiding improper construction and ensuring the construction quality. The construction method is simple and the construction efficiency is fast. The carbon emission in the mining process is reduced, the utilization rate of the post-mining space is improved, and the damage to the ecological environment is reduced.

[0057] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A method for constructing carbon storage space for negative carbon filling mining, characterized in that: The steps include: S1, through geological exploration, determine the lithology and thickness of the overlying rock layers, and divide the carbon storage space types into high-mining space and dynamic mining space according to the location of the hard and thick rock layers; S2, based on geological exploration and theoretical calculation, determine the height of the gas-conducting fracture zone after coal seam backfill mining; S3, backfill mining; When the carbon storage space type is high mining space, a closed wall is built every 50 to 300 m of advancement of the working face to form a filling section; When the carbon storage space type is mining space, gangue filling and grouting are carried out in the collapsed area above the coal body before and after the goaf to seal the carbon storage space to ensure that there is no gas leakage from the carbon storage space; S4, injecting carbon dioxide gas into the carbon storage space through pipelines, while monitoring carbon dioxide at the working face and monitoring surface rock movement on the ground to ensure the negative carbon filling effect; S5, after the section filling is completed, repeat steps S1 to S4 to fill the next section.

2. The method for constructing carbon storage space by negative carbon filling mining according to claim 1, characterized in that: The carbon storage space types are divided into two categories according to the location of hard and thick rock layers: when the roof of the coal seam is a hard and thick rock layer, the carbon storage space is a high mining space; when there is a hard and thick rock layer at a certain distance above the coal seam, the carbon storage space is a dynamic mining space.

3. The method for constructing carbon storage space by negative carbon filling mining according to claim 1, characterized in that: The enclosed wall is arranged in parallel with the working surface and has the same length, and both are rectangular spaces.

4. The method for constructing carbon storage space by negative carbon filling mining according to claim 1, characterized in that: In step S3, according to the position of the hard thick rock layer and the height of the gas-conducting fracture zone, a borehole is drilled from the tunnel to the top of the coal body in front and behind the goaf, and slurry is pumped into the borehole by a grouting pump to complete the gangue filling grouting.

5. The method for constructing carbon storage space by negative carbon filling mining according to claim 1, characterized in that: Use appropriate filling methods to carry out gangue filling and grouting above the coal body before and after the goaf; The composition of the paste filling material is "gangue + fly ash + cement + quicklime + accelerator". The specific proportion range is: slurry concentration 81-84%, fly ash 40-50%, gangue 35-45%, cement 5-15%, quicklime 0-3%, accelerator 2-4%. After fully mixing, fill it into the goaf.

6. The method for constructing carbon storage space by negative carbon filling mining according to claim 1, characterized in that: In step S3, after the filling of the coal bodies in front and behind the goaf is completed, a closed wall is constructed in the goaf filling area every 50 to 300 meters.

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