A method for coordinated mining of coal and geothermal energy in mines based on longwall working face

Abstract

The invention relates to the technical field of coal mining, and discloses a method for coordinated mining of coal and geothermal energy in a mine based on a longwall working face, comprising the following steps: excavating two mutually parallel first section lanes and a second section lane, and excavating a cut eye connecting the first section lane and the second section lane; recovering coal from the working face by a backward method from the cut eye, and densely filling the rear goaf area to form a water storage / heat extraction structure in the goaf area; constructing a retaining wall at the exit of the first section lane and the second section lane; excavating a third section lane parallel to the second section lane, and passing a plurality of water pipes through the third section lane toward the second section lane; and installing a water extraction pipe in the first section lane; the method for coordinated mining of coal and geothermal energy in a mine can realize coordinated mining of coal and geothermal energy in a mine, has a simple construction process, high heat extraction efficiency, utilizes underground abandoned space, and consumes mine solid waste materials on site.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, and in particular to a method for coordinated mining of mine coal and geothermal energy based on a longwall working face. Background Art

[0002] When coal mining reaches a certain depth, the entire mining environment will be in a high temperature state for a long time. In recent years, rich geothermal resources have gradually attracted attention because of their green and renewable characteristics.

[0003] Existing geothermal extraction technology mainly uses steel pipes as casing materials that are in direct contact with heat storage rock formations. In the actual operation of this geothermal extraction technology, the installation of steel pipes is complicated, the equipment investment is large, and the consumption is high. However, due to the low heat transfer coefficient of steel pipes, it is not conducive to heat conduction, which reduces the geothermal recovery efficiency, resulting in low economic benefits for the entire geothermal extraction process.

[0004] In view of this, we propose a method of coordinated mining of coal and geothermal energy in mines based on longwall working face to solve the above technical problems. Summary of the invention

[0005] The present invention proposes a method for coordinated mining of mine coal and geothermal energy based on a longwall working face. The method can realize coordinated mining of mine coal and geothermal energy. At the same time, the construction process is simpler than the traditional method and the heat extraction efficiency is high, so as to solve the shortcomings of the above-mentioned prior art.

[0006] The technical solution of the present invention is: a method for coordinated mining of coal and geothermal energy in a mine based on a longwall working face, comprising the following steps:

[0007] S1: excavating two mutually parallel first section roadways and second section roadways, and excavating a cutting eye connected to the first section roadway and the second section roadway to form a longwall coal mining working face;

[0008] S2: mining the coal from the working face by retreating from the cut hole, and filling the rear goaf densely, so that the goaf forms a water storage / heat extraction structure;

[0009] S3: construct a retaining wall at the exit of the first section roadway and the second section roadway, so that the retaining wall can seal the water storage / heat extraction structure;

[0010] S4: excavating a third section tunnel parallel to the second section tunnel at the working face to be mined, and laying a plurality of water pipes through the third section tunnel toward the second section tunnel; the water pipes are used to input cold water into the water storage / heat extraction structure;

[0011] S5: A water intake pipe is installed in the first section of the tunnel, and a water pumping station is connected to the water intake pipe; the water pumping station is used to pump cold water heated by the water storage / heat extraction structure out of the water storage / heat extraction structure, thereby realizing the collection of geothermal energy.

[0012] In at least one embodiment of the present disclosure, the water storage / heat extraction structure is formed by filling with loose gangue material or gangue-based high-porosity cementitious material; by using loose gangue material or gangue-based high-porosity cementitious material as the water storage / heat extraction structure, the underground abandoned space is fully utilized, and the mine solid waste materials are consumed on site, thereby achieving the purpose of large-scale and high-resource treatment of mine solid waste.

[0013] In at least one embodiment of the present disclosure, the ground height of the second section tunnel is higher than the ground height of the first section tunnel, so that cold water flows from the second section tunnel to the first section tunnel.

[0014] In at least one embodiment of the present disclosure, the plurality of water supply pipes are arranged along the top end of the side wall of the second section tunnel, and the water intake pipes are arranged along the bottom end of the side wall of the first section tunnel.

[0015] In at least one embodiment of the present disclosure, a plurality of the water pipes extend into the water storage / heat extraction structure so that the cold water input by the water pipes is in full contact with the water storage / heat extraction structure.

[0016] In at least one embodiment of the present disclosure, the first section tunnel and the second section tunnel are sealed with waterproof concrete on one side close to the water storage / heat extraction structure to prevent leakage of geothermal water.

[0017] In at least one embodiment of the present disclosure, if the mining face is not a downward mining face, a drainage channel is opened in the first section tunnel, and the drainage channel is inclined downward toward the retaining wall to facilitate the water intake pipe to smoothly extract water heated by the water storage / heat extraction structure.

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

[0019] 1. The method for coordinated mining of coal and geothermal energy in a mine based on a longwall working face proposed in the present invention, by excavating a cut eye connected to the first section roadway and the second section roadway, and by mining and compacting the rear goaf at the same time, completes the construction of a closed mine water storage / heat extraction structure during coal mining, and then realizes geothermal mining by setting up water supply / water extraction pipelines; compared with the geothermal mining technology in the prior art that uses steel pipes as casing materials in direct contact with the heat storage rock formation, the method for coordinated mining of coal and geothermal energy in a mine is cheap and simple, requires less equipment investment, and has a high geothermal recovery efficiency.

[0020] 2. The method of coordinated mining of coal and geothermal energy based on longwall working face proposed in the present invention makes full use of underground abandoned space by using loose gangue materials or gangue-based high-porosity cementitious materials as water storage / heat extraction structures, consumes mine solid waste materials on site, and achieves the purpose of large-scale and high-resource treatment of mine solid waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a top plan view of the working surface of the present invention.

[0022] Figure 2 It is a cross-sectional view of the top plane of the working surface of the present invention along the AA direction.

[0023] Description of reference numerals:

[0024] 1. Tunnel of the first section; 2. Tunnel of the second section; 3. Cutting eye; 4. Retaining wall; 5. Water storage / heat extraction structure; 6. Working face to be mined; 7. Tunnel of the third section; 8. Water pipe; 9. Water intake pipe; 10. Pumping station. DETAILED DESCRIPTION

[0025] The drawings in this disclosure are not drawn strictly according to the actual scale, and the specific size and quantity of each structure can be determined according to actual needs. The drawings described in this disclosure are only schematic diagrams of the structures.

[0026] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment 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.

[0027] Unless otherwise defined, the technical or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the invention belongs. The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Inside", "outside", "up", "down", "far", "near", "front", "back" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0028] Existing geothermal extraction technology mainly uses steel pipes as casing materials that are in direct contact with heat storage rock formations. The steel pipes are complex to install, have low heat transfer coefficients, are not conducive to heat conduction, and reduce geothermal recovery efficiency, resulting in problems such as large equipment investment, high consumption, and low economic benefits.

[0029] With the continuous exploitation of coal resources, a large amount of coal-based solid waste such as coal gangue and fly ash is generated, which not only occupies the land area of ​​the mining area, but also generates high transportation and processing costs, greatly increasing the production cost of the mine and posing a threat to the mine ecology. At present, there are many ways to deal with mine solid waste, but except for underground filling, the others are difficult to meet the requirements of large-scale consumption of solid waste. However, the current underground solid waste filling method has a low degree of utilization of solid waste. How to dispose of mine solid waste in large quantities and with high resource utilization has become a problem that needs to be solved urgently.

[0030] In view of this, we propose a method of coordinated mining of mine coal and geothermal energy based on longwall working face. This method can realize the coordinated mining of mine coal and geothermal energy. At the same time, the construction process is simpler than the traditional method, the heat extraction efficiency is high, and the underground waste space is utilized to consume mine solid waste materials on site.

[0031] Combination Figure 1 to Figure 2 As shown, a method for coordinated mining of coal and geothermal energy in a mine based on a longwall working face comprises the following steps:

[0032] S1: excavating two mutually parallel first section roadways 1 and second section roadways 2, and excavating a cutting eye 3 connected to the first section roadway 1 and the second section roadway 2; the cutting eye 3 is perpendicular to the first section roadway 1 and the second section roadway 2; so as to form a longwall coal mining working face;

[0033] S2: mining the coal from the working face by retreating from the cut hole 3, and filling the rear goaf densely, so that the goaf forms a water storage / heat extraction structure 5; the entire water storage / heat extraction structure 5 is rectangular;

[0034] S3: constructing a retaining wall 4 at the exit of the first section tunnel 1 and the second section tunnel 2, so that the retaining wall 4 closes the water storage / heat extraction structure 5; thereby completing the construction of the closed mine water storage / heat extraction structure while coal mining;

[0035] S4: excavating a third section tunnel 7 parallel to the second section tunnel 2 at the working face 6 to be mined, and laying a plurality of water pipes 8 through the third section tunnel 7 toward the second section tunnel 2; the plurality of water pipes 8 are evenly arranged, and the plurality of water pipes 8 are connected to a main water supply pipe; the water pipes 8 are used to supply cold water to the water storage / heat extraction structure 5;

[0036] S5: A water intake pipe 9 is installed in the first section tunnel 1, and a water pumping station 10 is connected to the water intake pipe 9; the water pumping station 10 is used to pump the cold water heated by the water storage / heat extraction structure 5 out of the water storage / heat extraction structure 5, thereby realizing the collection of geothermal energy.

[0037] As an alternative embodiment, the water storage / heat extraction structure 5 is formed by filling with loose gangue material or gangue-based high-porosity cementitious material; by using loose gangue material or gangue-based high-porosity cementitious material as the water storage / heat extraction structure, the underground abandoned space is fully utilized, and the mine solid waste materials are consumed on site, thereby achieving the purpose of large-scale and high-resource treatment of mine solid waste.

[0038] As an alternative embodiment, the ground height of the second section tunnel 2 is higher than the ground height of the first section tunnel 1; the height difference between the second section tunnel 2 and the first section tunnel 1 facilitates the cold water entering the second section tunnel 2 to flow to the first section tunnel 1, thereby allowing the cold water to fully contact the water storage / heat extraction structure 5 to achieve the collection of geothermal energy.

[0039] As an alternative embodiment, multiple water pipes 8 are arranged along the top of the side wall of the second section tunnel 2, and the water intake pipe 9 is arranged along the bottom of the side wall of the first section tunnel 1; specifically, the water intake pipe 9 is set on the retaining wall 4 of the first section tunnel 1, the water intake pipe 9 is arranged along the bottom of the retaining wall 4, and the water intake pipe 9 extends into the water storage / heat extraction structure 5; this arrangement can facilitate the water intake pipe 9 to smoothly extract water heated by the water storage / heat extraction structure 5.

[0040] As an alternative embodiment, multiple water pipes 8 extend into the water storage / heat extraction structure 5; the water pipes 8 extending into the water storage / heat extraction structure 5 can enable the cold water to fully contact the water storage / heat extraction structure 5, thereby allowing the cold water to be heated by the water storage / heat extraction structure 5.

[0041] As an alternative embodiment, the first section tunnel 1 and the second section tunnel 2 are sealed on one side close to the water storage / heat extraction structure 5 using waterproof concrete; the selection of the waterproof concrete can prevent the water in the water storage / heat extraction structure 5 from seeping out of the first section tunnel 1 and the second section tunnel 2 during geothermal collection.

[0042] As an alternative embodiment, if the mining working face is not a downward mining working face, a drainage channel is opened in the first section tunnel 1, and the drainage channel is inclined downward toward the retaining wall 4; the setting of the inclined drainage channel facilitates the water intake pipe 9 to smoothly extract the water heated by the water storage / heat extraction structure 5.

[0043] The above embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above embodiments, ordinary technicians in this field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions for implementing the present invention, and should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for coordinated mining of coal and geothermal energy in a mine based on a longwall working face, characterized in that: The following steps are involved: S1: excavating two mutually parallel first section tunnels (1) and second section tunnels (2), and excavating a cutting eye (3) connected to the first section tunnel (1) and the second section tunnel (2) to form a longwall coal mining working face, wherein the ground height of the second section tunnel (2) is higher than the ground height of the first section tunnel (1); S2: mining the coal from the working face by a backward method from the cut (3), and densely filling the rear goaf so that the goaf forms a water storage / heat extraction structure (5), wherein the water storage / heat extraction structure (5) is formed by filling with gangue bulk material or gangue-based high-porosity cementitious material; S3: constructing a water retaining wall (4) at the exit of the first section tunnel (1) and the second section tunnel (2), so that the water retaining wall (4) can seal the water storage / heat extraction structure (5); S4: excavating a third section tunnel (7) parallel to the second section tunnel (2) at the working face to be mined (6), and laying a plurality of water pipes (8) through the third section tunnel (7) in the direction of the second section tunnel (2), wherein the plurality of water pipes (8) are laid along the top of the side wall of the second section tunnel (2); S5: installing a water intake pipe (9) in the first section tunnel (1), wherein the water intake pipe (9) is arranged along the bottom end of the side wall of the first section tunnel (1).

2. A method for coordinated mining of coal and geothermal energy in a mine based on a longwall working face as claimed in claim 1, characterized in that: The plurality of water delivery pipes (8) extend into the water storage / heat extraction structure (5).

3. The method for coordinated mining of coal and geothermal energy in a mine based on a longwall working face according to claim 1, characterized in that: The first section tunnel (1) and the second section tunnel (2) are sealed on one side close to the water storage / heat extraction structure (5) using waterproof concrete.

4. A method for coordinated mining of coal and geothermal energy in a mine based on a longwall working face as claimed in claim 1, characterized in that: If the mining working face is not a downward mining working face, a drainage channel is opened in the first section tunnel (1), and the drainage channel is arranged to be inclined downward toward the retaining wall (4).

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