A method for extracting geothermal energy by arranging pipelines for solid waste cemented functional filling bodies

Abstract

The present invention discloses a method for extracting geothermal energy by arranging pipelines with solid waste cemented functional filling bodies. In the process of continuous mining and filling, the geothermal extraction pipelines are laid while the paste is filled in the branch tunnels of the goaf. Then, the geothermal extraction pipelines in multiple parallel branch tunnels are connected with the heat extraction branch pipes laid in the return air chute and the transport chute. The geothermal extraction pipelines in all branch tunnels are then connected to the heat extraction main pipes laid in the return air chute and the transport chute, forming an underground heat extraction system. The present invention adopts continuous segmented filling and laying. The filling main pipeline, the terminal filling pipeline and the geothermal extraction pipeline used are all segmented. When performing segmented grouting filling, it can not hinder the operation of the next section of the pipeline, the isolation retaining wall and the card slot, which can greatly improve the operation efficiency. At the same time, the present invention uses the solid waste in the mine as a filling body, which can effectively utilize the waste and save filling costs.

Description

Technical Field

[0001] The present invention relates to the technical field of mine solid waste disposal and mine geothermal development, and in particular to a method for extracting geothermal energy by arranging pipelines with solid waste cemented functional filling bodies. Background Art

[0002] Driven by green coal mining and renewable geothermal energy development, the realization of mine solid waste disposal and mine geothermal development has become a general trend. Using mine solid waste filling to achieve mine geothermal development is an effective way to achieve these goals, but the relevant technical methods are currently lacking. Summary of the Invention

[0003] In order to achieve the above-mentioned purpose, the present invention provides a method for extracting geothermal energy by arranging pipelines with solid waste cemented functional filling bodies, which can realize green disposal of solid waste and development of geothermal energy at the same time.

[0004] The technical solution adopted by the present invention is: a method for extracting geothermal heat by arranging pipelines with solid waste cemented functional filling bodies, comprising the following steps:

[0005] Step S1: Delineate the continuous segmented filling space of the mined branch tunnels on the working face, and lay the main filling pipe along the bottom plate of the branch tunnels;

[0006] Step S2: excavating slots on the top plate of the branch tunnel and the bottom plate below it, excavating another set of slots along the length of the branch tunnel, and then installing isolation retaining walls on the two sets of slots to construct the first section of filling space;

[0007] Step S3: Connect the terminal filling pipe to the main filling pipe, with the other end passing through the isolation retaining wall and extending into the first filling space, and the geothermal extraction pipe passing through the two isolation retaining walls, with both ends located outside the two isolation retaining walls;

[0008] Step S4: pouring solid waste cementing functional filling paste into the first filling space through the main filling pipe and the terminal filling pipe;

[0009] Step S5: Backward excavation of the slot to construct the next section of filling space, and then installing the geothermal extraction pipe and connecting it to the geothermal extraction pipe in the first section of filling space;

[0010] Step S6: After the first section of the filling space is poured, the filling pump is turned off, part of the main filling pipe is disassembled, and the end filling pipe is moved so that its outlet is located in the next section of the filling space;

[0011] Step S7, repeat steps S3-S6 until the functional buried pipe filling of a single branch tunnel is completed; step S8, repeat steps S1 to S6, complete the buried pipe filling of each parallel branch tunnel, and then connect the two ends of the geothermal extraction pipe of each branch tunnel to the heat extraction branch pipe in the return air chute and the transport chute, and then connect all the heat extraction branch pipes to the heat extraction main pipe, thereby forming a buried pipe heat exchange system.

[0012] As a further improvement of the present invention, the main filling pipe is a stainless steel pipe and is installed in sections, with each section being 3-5 meters long.

[0013] As a further improvement of the present invention, the card slots are respectively located in the top plate and bottom plate of the branch tunnel, four on the top and four on the bottom. The depth of a single card slot is 1 / 10 of the height of the branch tunnel, the width is 1 / 10 of the width of the branch tunnel, and the thickness is 1 / 3 of the isolation retaining wall.

[0014] As a further improvement of the present invention, the isolation retaining wall is an arched structure assembled from four prefabricated modules, and through holes for installing end filling pipes and geothermal extraction pipes are reserved on the retaining wall.

[0015] As a further improvement of the present invention, the geothermal extraction pipeline is made of high thermal conductivity stainless steel pipe, and the length of each segment is 3-5m.

[0016] As a further improvement of the present invention, the end filling pipe consists of a vertical section and a horizontal section, one end of the horizontal section is supported and fixed by a reserved through hole of the isolation retaining wall, and the other end is supported and fixed by a spiral telescopic support rod.

[0017] As a further improvement of the present invention, the solid waste cementing functional filling paste is composed of porous volcanic rock coarse aggregate adsorbed with paraffin, gangue coarse aggregate, gangue fine aggregate, fly ash, cement and treated mine water. The specific proportion parameters are: slurry concentration 80%, volcanic rock coarse aggregate replacement rate 50%, sand rate 40%, bone-cement ratio 2:1, and fly ash output 0.2.

[0018] As a further improvement of the present invention, the excavation of the slots in the rear filling space, the layout of the isolation retaining wall and the installation of the rear geothermal extraction pipeline are completed simultaneously with the pouring of the solid waste bonding functional filling paste in the first filling space.

[0019] As a further improvement of the present invention, the heat extraction branch pipe and the heat extraction main pipe are both insulated stainless steel pipes.

[0020] The beneficial effects of the present invention are:

[0021] (1) The present invention can unify the filling of goaf and geothermal heat extraction in a continuous mining and filling coal mining method. On the one hand, it can make full use of solid waste and prevent surface subsidence. On the other hand, it can form a geothermal heat extraction system for geothermal development.

[0022] (2) The paste filling work is carried out simultaneously with the laying of geothermal pipes, which can improve the work efficiency of the entire project;

[0023] (3) Since the buried pipe filling in each branch tunnel is completed in sections, the main filling pipe and the terminal filling pipe are both installed in sections, and the isolation retaining wall is installed in a spliced ​​manner. Therefore, when grouting the front filling space, the subsequent opening and installation of the isolation retaining wall and the card slot can be carried out simultaneously to improve the laying efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Figure 1 Schematic diagram of segmented functional buried pipe filling of mined branch lanes in the working face in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of a branch lane slot in an embodiment of the present invention;

[0027] Figure 3 The front view and side view of the isolation retaining wall in the embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of fixing the support rod of the end filling pipe in an embodiment of the present invention;

[0029] Figure 5 This is a diagram showing the functional buried pipe filling effect of the goaf area of ​​the working face in an embodiment of the present invention;

[0030] In the figure, 1 is the main filling pipe; 2 is the card slot; 3 is the isolation retaining wall; 4 is the geothermal extraction pipe; 5 is the end filling pipe; 6 is the solid waste bonding functional filling paste; 7 is the heat extraction branch pipe; 8 is the heat extraction main pipe; 9 is the spiral telescopic support rod. DETAILED DESCRIPTION

[0031] Figure 1 For the continuous segmented pipe laying process diagram, please refer to Figure 1 The present invention provides a method for extracting geothermal energy by arranging pipelines for solid waste cemented functional filling bodies, comprising the following steps:

[0032] Step S1: First, define the continuous segmented filling space of the mined branch tunnel at the working face and lay the main filling pipe 1 along the branch tunnel floor. The main filling pipe 1 is laid continuously and segmented, made of stainless steel pipe, with segment lengths of 3 to 5 meters, inner diameters of 18 to 22 cm, and wall thicknesses of 1 to 1.5 cm.

[0033] Step S2: excavate slots 2 on the top plate of the branch tunnel and the bottom plate below it, and excavate another set of slots 2 along the length of the branch tunnel, and then install isolation retaining walls 3 on the slots 2 to construct the first section of filling space. Figure 2 As shown, the slots 2 are located in the top and bottom plates of the branch tunnel, four on each side, and are used to install and fix the isolation retaining wall 3. The depth of a single slot 2 is 1 / 10 of the height of the branch tunnel, the width is 1 / 10 of the width of the branch tunnel, and the thickness is 1 / 3 of the isolation retaining wall 3. Figure 3 The figure shows the side and front views of the isolation retaining wall 3. The isolation retaining wall 3 is an arched structure assembled from four prefabricated modules, with holes reserved in the center for installing the terminal filling pipe 5 and the geothermal extraction pipe 4. The module is 20-25 cm thick, 1 / 2 the width of the branch tunnel, 6 / 5 the full-scale height of the branch tunnel, and 1 / 10 the arch height of the branch tunnel. The thickness of the concave / convex mating part of the module is 1 / 2 the thickness of the module, the width is equal to the module width, and the depth is 1 / 10 the height of the branch tunnel. The dimensions of the module's external fixing block match the slot 2.

[0034] Step S3: Connect the terminal filling pipe 5 to the main filling pipe 1. The other end of the pipe passes through the isolation retaining wall 2 and extends into the first filling space. The geothermal extraction pipe 4 passes through the two isolation retaining walls 3, with both ends located outside the two isolation retaining walls 3. The terminal filling pipe 5 consists of a vertical section and a horizontal section. The horizontal section is connected in sections. One end of the horizontal section is fixed by a reserved through hole in the isolation retaining wall 3, and the other end is fixed by a spiral telescopic support rod 9. Figure 4 As shown, spiral telescopic struts 9 are fixed at both ends of the branch tunnel, securing the horizontal section of the terminal filling pipe 5 and preventing it from tilting. Both ends of the geothermal extraction pipe 4 are secured by reserved through-holes in the isolation retaining wall 3. Made of high-thermal-conductivity stainless steel pipe, it has an inner diameter of 20-25 cm, a wall thickness of 0.8-1 cm, and segment lengths of 3-5 m.

[0035] Step S4: Pour a solid waste-bonded functional filling paste 6 into the first filling space through the main filling pipe 1 and the terminal filling pipe 5. This solid waste-bonded functional filling paste 6 consists of paraffin-absorbed porous volcanic rock coarse aggregate, gangue coarse aggregate, gangue fine aggregate, fly ash, cement, and treated mine water. The specific mix parameters are: 80% slurry concentration, 50% gangue replacement ratio of volcanic rock coarse aggregate, 40% sand ratio, 2:1 aggregate-cement ratio, and 0.2% fly ash yield. The volcanic rock coarse aggregate and the gangue coarse aggregate have the same gradation: naturally graded and have a maximum particle size of 12 mm. The cement is ordinary Portland cement with a PO 42.5 rating, and the fly ash is secondary fly ash.

[0036] Step S5: Excavate the slot 2 in a backward manner to construct the next filling space, then install the geothermal extraction pipeline 4 and connect it to the geothermal extraction pipeline 4 in the first filling space. The excavation of the slot 2 in the second filling space, the layout of the isolation retaining wall 3, and the installation of the second geothermal extraction pipeline 4 are completed simultaneously with the pouring of the solid waste bonding functional filling paste 6 in the first filling space, thus greatly improving the efficiency of filling and pipeline installation.

[0037] Step S6: After the first section of the filling space is poured, the filling pump is turned off, part of the main filling pipe 1 is disassembled, and the terminal filling pipe 5 is moved so that its outlet is located in the next section of the filling space.

[0038] Step S7: Repeat steps S3 through S6 until the entire branch tunnel is completely filled with functional buried pipes. After completion, the branch tunnel is solid with the filling material and contains the geothermal extraction pipe 4. The connected geothermal extraction pipe 4 is the length of a single branch tunnel. Furthermore, the geothermal extraction pipe 4 is arranged in two layers, upper and lower, and can also be arranged in a multi-layer array as required.

[0039] Step S8, please refer to Figure 5 Repeat steps S1 through S6 until all parallel branch tunnels are filled with buried pipes. Then, in the return air chute and transport chute, connect the ends of each branch tunnel's geothermal extraction pipe 4 to the heat extraction branch pipe 7. Then, connect all heat extraction branch pipes 7 to the heat extraction main pipe 8, thus forming a buried pipe heat exchange system. Both the heat extraction branch pipes 7 and the heat extraction main pipe 8 are insulated stainless steel pipes. The heat extraction branch pipes 7 have an inner diameter of 30-35 cm and a wall thickness of 1-1.5 cm, while the heat extraction main pipe 8 has an inner diameter of 40-45 cm and a wall thickness of 2-3 cm.

[0040] Please refer to Figure 5 The present invention employs a continuous mining and filling method. A coalfield is mined from left to right, with each mining unit forming a branch lane. As mining continues to the right, multiple mined branch lanes remain. Local heat extraction pipes 4 are arranged along the length of each branch lane, with their ends connected by heat extraction branch pipes 7. The extraction branch pipes 7 in all branch lanes are then connected to the heat extraction main pipe 8, completing the installation of a heat extraction system. During heat extraction, water is filled into the geothermal extraction pipes 4, which circulates and absorbs heat from the underground rock, completing geothermal development.

[0041] The present invention has the following advantages: First, the goaf filling and the pipe extraction system are constructed simultaneously, and the construction is coordinated to improve construction efficiency; second, the goaf filling uses the gangue and mine water in the mine, and is completed underground, so the waste can be reused to prevent surface subsidence; third, during the segmented grouting, the subsequent slot excavation and the installation of the isolation retaining wall can be carried out at the same time, which can greatly improve work efficiency; fourth, the main filling pipe 1 and the end filling pipe 5 used in this method are both segmented structures, which is convenient for the implementation of segmented filling work, and the isolation retaining wall 3 is a spliced ​​structure, so as not to hinder the disassembly of the horizontal section of the end filling pipe 5, and to facilitate the simultaneous installation of the rear section isolation retaining wall 3.

[0042] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Various changes that can be made within the scope of knowledge possessed by technicians in the relevant technical field without departing from the spirit of the present invention are all within the scope of protection of the claims of the present invention.

Claims

1. A method for extracting geothermal energy by arranging pipelines for solid waste cemented functional filling bodies, characterized in that: The following steps are involved: Step S1, demarcate the continuous segmented filling space of the mined branch tunnels on the working face, and lay the main filling pipe (1) along the bottom plate of the branch tunnel; Step S2: excavating a slot (2) on the top plate of the branch tunnel and the bottom plate thereunder, excavating another set of slots (2) along the length direction of the branch tunnel, and then installing isolation retaining walls (3) on the two sets of slots (2) to construct a first section of filling space; Step S3, connecting the terminal filling pipe (5) to the main filling pipe (1), with the other end of the terminal filling pipe passing through the isolation retaining wall (3) and extending into the first section filling space, and the geothermal extraction pipe (4) passing through the two isolation retaining walls (3), with both ends located outside the two isolation retaining walls (3); Step S4, pouring the solid waste bonding functional filling paste (6) into the first filling space through the main filling pipe (1) and the terminal filling pipe (5); Step S5: excavating the card slot (2) in a backward manner to construct the next section of filling space, and then installing the geothermal extraction pipe (4) and connecting it to the geothermal extraction pipe (4) in the first section of filling space; Step S6: After the first section of the filling space is poured, the filling pump is turned off, part of the main filling pipe (1) is disassembled, and the end filling pipe (5) is moved so that its outlet is located in the next section of the filling space; Step S7: Repeat steps S3 to S6 until the functional buried pipe filling of a single branch tunnel is completed; Step S8, repeating steps S1 to S6, completing the filling of buried pipes in all parallel branch tunnels, then connecting the two ends of the geothermal extraction pipeline (4) of each branch tunnel to the heat extraction branch pipe (7) in the return air chute and the transport chute, and then connecting all the heat extraction branch pipes (7) to the heat extraction main pipe (8), thereby forming a buried pipe heat exchange system.

2. The method for extracting geothermal energy by arranging pipelines for solid waste cemented functional filling bodies according to claim 1 is characterized in that: The main filling pipe (1) is a stainless steel pipe and is installed in sections, with each section being 3-5 meters long.

3. The method for extracting geothermal energy by arranging pipelines for solid waste cemented functional filling bodies according to claim 1 is characterized in that: The card slots (2) are respectively located in the top plate and bottom plate of the branch tunnel, four on the top and four on the bottom. The depth of a single card slot (2) is 1 / 10 of the height of the branch tunnel, the width is 1 / 10 of the width of the branch tunnel, and the thickness is 1 / 3 of the isolation retaining wall (3).

4. The method for extracting geothermal energy by arranging pipelines for solid waste cemented functional filling bodies according to claim 1 is characterized in that: The isolation retaining wall (3) is an arched structure assembled from four prefabricated modules, and through holes for installing the terminal filling pipe (5) and the geothermal extraction pipe (4) are reserved on the retaining wall.

5. The method for extracting geothermal energy by arranging pipelines for solid waste cemented functional filling bodies according to claim 1 is characterized in that: The geothermal extraction pipeline (4) is made of high thermal conductivity stainless steel pipe, and the length of each segment is 3-5m.

6. The method for extracting geothermal energy by arranging pipelines for solid waste cemented functional filling bodies according to claim 1 is characterized in that: The terminal filling pipe (5) is composed of a vertical section and a horizontal section. One end of the horizontal section is supported and fixed by a reserved through hole of the isolation retaining wall (3), and the other end is supported and fixed by a spiral telescopic support rod (9).

7. The method for extracting geothermal energy by arranging pipelines for solid waste cemented functional filling bodies according to claim 1 is characterized in that: The solid waste cementing functional filling paste (6) is composed of porous volcanic rock coarse aggregate adsorbed with paraffin, gangue coarse aggregate, gangue fine aggregate, fly ash, cement and treated mine water, and the specific proportion parameters are: slurry concentration 80%, volcanic rock coarse aggregate replacement rate 50%, sand rate 40%, bone-cement ratio 2:1, and fly ash output 0.

2.

8. The method for extracting geothermal energy by arranging pipelines for solid waste cemented functional filling bodies according to claim 1, characterized in that: The excavation of the slot (2) in the rear filling space, the layout of the isolation retaining wall (3) and the installation of the rear geothermal extraction pipeline (4) are completed simultaneously with the pouring of the solid waste bonding functional filling paste (6) in the first filling space.

9. The method for extracting geothermal energy by arranging pipelines for solid waste cemented functional filling bodies according to claim 1, characterized in that: The heat extraction branch pipe (7) and the heat extraction main pipe (8) are both heat-insulating stainless steel pipes.

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