In-situ ucg process coal body spalling dynamic monitoring physical simulation device and method

Abstract

This invention relates to the field of underground coal gasification technology and discloses a physical simulation device and method for dynamic monitoring of coal body spalling in an in-situ UCG process. The device includes an outer chamber with a sealed first cavity, an extraction port and an injection port connected to the first cavity; an inner chamber with a semi-open second cavity for holding the coal body; a horizontal mechanism connected to the inner chamber; multiple pressurizing mechanisms on the inner chamber for pressurizing the coal body horizontally and vertically; a weight acquisition mechanism at the bottom of the first cavity, with the open end of the second cavity facing the weight acquisition mechanism; and an ignition mechanism on the outer chamber for igniting the coal body. This invention can monitor coal body spalling characteristics in real time during underground coal gasification and, combined with coal composition and structural spatial characteristic characterization technology, can analyze the control effect of coal composition on spalling.

Description

Technical Field

[0001] This invention relates to the field of underground coal gasification technology, and in particular to a physical simulation device and method for dynamic monitoring of coal body stripping in in-situ UCG processes. Background Technology

[0002] Underground coal gasification (UCG) involves various processes including drying, pyrolysis, chemical reactions, and mechanical action, and is a major driver of gasification cavity development. Among these processes, coal spalling is one of the cavity growth mechanisms in underground coal gasification, resulting from the interconnection of fractures within the coal seam, leading to the shedding of small coal particles. It plays a crucial role by providing a higher surface area to improve performance. Currently, the mechanism and characterization of spalling are unclear, and there are no well-established experimental techniques to measure and monitor the dynamic spalling characteristics of coal. Furthermore, due to the heterogeneity of coal, spalling behavior varies significantly, which severely restricts the development of technologies such as UCG gasification cavity stability evaluation, stabilization techniques, and process control processes. Therefore, conducting in-situ physical simulations for dynamic monitoring of coal spalling in the UCG process is of great significance for applications in medium-deep underground coal gasification engineering. Summary of the Invention

[0003] The purpose of this invention is to provide a physical simulation device and method for dynamic monitoring of coal body stripping in in-situ UCG process, aiming to solve or improve at least one of the above-mentioned technical problems.

[0004] To achieve the above objectives, the present invention provides the following solution: The present invention provides a physical simulation device for in-situ dynamic monitoring of coal body stripping during UCG processes, comprising:

[0005] The outer chamber has a sealed first cavity inside, and the outer chamber has an extraction port and a first injection port that are connected to the first cavity.

[0006] An inner chamber is located within the first cavity, and a semi-open second cavity is provided inside the inner chamber for placing coal.

[0007] A horizontal mechanism is installed on the outer compartment and connected to the inner compartment;

[0008] Multiple pressurizing mechanisms are installed on the inner chamber, and the multiple pressurizing mechanisms are used to pressurize the coal body in the horizontal and vertical directions;

[0009] A weight acquisition mechanism is disposed at the bottom of the first cavity, and the open end of the second cavity faces the weight acquisition mechanism;

[0010] An ignition mechanism is provided on the outer chamber, and the ignition mechanism is used to ignite the coal body.

[0011] Optionally, the outer warehouse includes:

[0012] The first compartment is open at one end;

[0013] The base is detachably connected to the open end of the first compartment by a plurality of fixing bolts, and the first compartment and the base form the first cavity.

[0014] Optionally, the inner compartment includes:

[0015] The top plate is connected to the horizontal mechanism;

[0016] Multiple side panels are connected to the top plate;

[0017] Multiple base plates are detachably connected to multiple side plates via multiple fixing bolts, and the top plate, multiple side plates, and multiple base plates form the second cavity;

[0018] The multiple pressurizing mechanisms are respectively disposed on the multiple side plates and the multiple base plates.

[0019] Optionally, a plurality of jacks are provided between the base plate and the base.

[0020] Optionally, the pressurization mechanism includes:

[0021] Multiple piston chambers are provided, each with a piston connected to it via piston fluid drive, and a second injection port is provided at one end of each piston chamber.

[0022] A pressure-applying plate is connected to multiple pistons via multiple pressure-bearing columns, and the pressure-applying plate is used to press against the coal body.

[0023] Optionally, the outer compartment is provided with a plurality of third injection ports, which are connected to a plurality of second injection ports.

[0024] Optionally, a first sealing ring is provided between the first cabin and the base.

[0025] Optionally, a second sealing ring is provided between the pressure applying plate and the pressure bearing column.

[0026] Optionally, a support frame may also be included, which is connected to the outer compartment.

[0027] This invention also provides a physical simulation method for in-situ dynamic monitoring of coal seam exfoliation during UCG processes, comprising:

[0028] Prepare the coal body and place it into the second cavity;

[0029] The coal body is pressurized in both horizontal and vertical directions by multiple pressurizing mechanisms;

[0030] A vaporizing agent is injected into the first cavity through the first injection port, while data from the horizontal mechanism and the weight acquisition mechanism are recorded simultaneously.

[0031] The coal body is ignited by the ignition mechanism;

[0032] Extract the morphological features of the first cavity;

[0033] The characteristics and patterns of coal spalling are analyzed by combining the original macroscopic composition and fracture distribution characteristics of the coal body with data from horizontal and weight acquisition mechanisms.

[0034] This invention discloses the following technical effects: by placing coal in the second cavity, the in-situ UCG process can be simulated through the first injection port, multiple pressurization mechanisms, weight acquisition mechanisms, and ignition mechanisms. During the simulation, the thermal spalling law of different types of coal can be explored by using a horizontal mechanism and monitoring the changes in coal weight, the location and weight characteristics of spalling material. The spalling characteristics of coal during underground coal gasification can be monitored in real time. Combined with the coal composition and structural spatial characteristic characterization technology, the control effect of coal composition on spalling can be analyzed. Attached Figure Description

[0035] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0036] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0037] Figure 2 This is a schematic diagram of the structure of the substrate of the present invention;

[0038] Figure 3 This is a front sectional view of the base plate of the present invention;

[0039] Figure 4 This is a top view of the base plate of the present invention.

[0040] In the diagram: 1. Support frame; 2. First chamber; 3. Horizontal mechanism; 4. Top plate; 5. Base; 6. Fixing screw; 7. Extraction port; 8. First injection port; 9. Weight monitoring integrator; 10. Miniature gravity sensor; 11. Pressurization mechanism; 12. Coal body; 14. First sealing ring; 15. Side plate; 16. Bottom plate; 17. Third injection port; 18. Jack; 19. Ignition mechanism; 21. Second injection port; 22. Bolt hole; 23. Pressure application plate; 24. Pressure-bearing column; 25. Piston; 26. Second sealing ring; 27. Piston fluid. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Reference Figures 1-4 This invention provides a physical simulation device for in-situ dynamic monitoring of coal seam exfoliation during UCG processes, comprising:

[0044] The outer chamber has a sealed first cavity inside. The outer chamber has an extraction port 7 and a first injection port 8 connected to the first cavity. The first injection port 8 is used to inject a gasifying agent and inject helium later.

[0045] The inner chamber is located within the first cavity, and inside the inner chamber is a semi-open second cavity, which is used to hold the coal body 12.

[0046] Horizontal mechanism 3 is installed on the outer warehouse and is connected to the inner warehouse;

[0047] Multiple pressurizing mechanisms 11 are installed on the inner chamber, and the multiple pressurizing mechanisms 11 are used to pressurize the coal body 12 in the horizontal and vertical directions;

[0048] A weight acquisition mechanism is located at the bottom of the first cavity, and the open end of the second cavity faces the weight acquisition mechanism.

[0049] Ignition mechanism 19 is installed on the outer compartment and is used to ignite the coal body 12.

[0050] By placing the coal body 12 into the second cavity, the in-situ UCG process can be simulated through the first injection port 8, multiple pressurization mechanisms, weight acquisition mechanism, and ignition mechanism 19. During the simulation, the thermal spalling law of different types of coal can be explored by using the horizontal mechanism 3 and monitoring the weight change of the coal body 12, the location and weight characteristics of the spalling material. The spalling characteristics of the coal body during underground coal gasification can be monitored in real time. Combined with the coal composition and structural spatial characteristic characterization technology, the control effect of coal composition on spalling can be analyzed.

[0051] Furthermore, the weight acquisition mechanism includes a weight monitoring integrator 9 and multiple miniature gravity sensors 10 mounted on the weight monitoring integrator. Specifically, there are 100 miniature gravity sensors 10 evenly distributed, with a sensor accuracy of ±0.001g. Each sensor is equipped with a high-temperature resistant cover layer and can be connected to an external computer to record the weight change characteristics of each sensor in real time. The weight monitoring integrator 9 has a size of 10*10*5cm.

[0052] Furthermore, the ignition mechanism 19 is an adjustable-length electric spark ignition device used for UCG ignition. Before ignition, a combustion aid is applied to the pre-ignition point at the bottom center of the coal body 12.

[0053] Furthermore, the dimensions of the first cavity are 50*40*40cm.

[0054] Furthermore, the dimensions of the second cavity are 40*30*20cm.

[0055] Furthermore, the coal body 12 has dimensions of 40*30*20cm. Before placement, the coal body needs to be ground flat and smooth. When in use, an external lifting device is required to lift the coal body 12 to the designated position.

[0056] In one embodiment of the present invention, the outer warehouse includes:

[0057] First compartment 2, one end is open;

[0058] The base 5 is detachably connected to the open end of the first compartment 2 by a plurality of fixing bolts 6, and a first cavity is formed between the first compartment 2 and the base 5.

[0059] In one embodiment of the present invention, the inner compartment includes:

[0060] Top plate 4 is connected to horizontal mechanism 3;

[0061] Multiple side panels 15 are connected to the top panel 4;

[0062] Multiple base plates 16 are detachably connected to multiple side plates 15 by multiple fixing bolts 6, and a second cavity is formed between the top plate 4, the multiple side plates 15 and the multiple base plates 16;

[0063] Multiple pressurizing mechanisms 11 are respectively installed on multiple side plates 15 and multiple bottom plates 16.

[0064] Both the side plate 15 and the bottom plate 16 have bolt holes 22 for mounting and fixing screws 6.

[0065] The bottom plate measures 40*15*5cm, with the portion in contact with the bottom of coal body 12 measuring 40*10*5cm.

[0066] Furthermore, the horizontal mechanism 3 adopts a high-precision digital balance, which is connected to the top plate 4 through a hook. The high-precision balance can collect the weight change curves of the inner silo and coal body 12 in real time. The high-precision balance has a range of -5 to 5 kg and an accuracy of ±0.01 g. During the experiment, the total weight of coal body 12 and inner silo is recorded as zero, and the overall weight change rate is recorded in negative form, which is the weight reduction of coal body 12.

[0067] In one embodiment of the present invention, a plurality of jacks 18 are provided between the base plate and the base. The height of the jacks 18 is controllable within a range of 8 to 12 cm with a control accuracy of ±0.1 cm. They are used to support the inner chamber base plate. Note that the top of the jacks 18 should be in a state of almost contact with the inner chamber base plate to prevent the reaction force generated during pressurization from damaging the overall structure of the device.

[0068] In one embodiment of the present invention, the pressurizing mechanism 11 includes:

[0069] Multiple piston chambers are connected to pistons 25 via piston fluid 27, and a second injection port 21 is provided at one end of each piston chamber.

[0070] The pressure application plate 23 is connected to multiple pistons 25 via multiple pressure-bearing columns 24, and the pressure application plate 23 is used to resist the coal body 12.

[0071] Each pressurizing mechanism 11 has 3 piston chambers.

[0072] In one embodiment of the present invention, a plurality of third injection ports 17 are provided on the outer compartment, and the plurality of third injection ports 17 are connected to a plurality of second injection ports 21.

[0073] The third injection port 17 consists of six ports, three of which are located on the left and right side walls of the outer chamber, and are used to inject piston fluid 27 into the live second injection port 21.

[0074] In one embodiment of the present invention, a first sealing ring 14 is provided between the first cabin 2 and the base 5.

[0075] In one embodiment of the present invention, a second sealing ring 26 is provided between the pressure application plate 23 and the pressure-bearing column 24.

[0076] Both the first sealing ring 14 and the second sealing ring 26 are high-temperature resistant sealing rings.

[0077] In one embodiment of the present invention, a support frame 1 is also included, which is connected to the outer compartment.

[0078] This invention also provides a physical simulation method for in-situ dynamic monitoring of coal seam exfoliation during UCG processes, comprising:

[0079] 1. Prepare coal body 12 and place it in the second cavity. Specifically, select coal body 12 with complete coal structure. Use a wire cutting instrument to prepare a rectangular coal body 12 with dimensions of 40*30*20cm and grind it smooth and flat. Use a CT scanning device to perform grayscale scanning on the selected coal body 12 to characterize the macroscopic coal and rock composition and fracture spatial distribution characteristics of the coal body 12. Apply bamboo dye to the predetermined ignition position. Use a lifting device to lift the coal body 12 to the appropriate position in the inner chamber according to a certain orientation. Then install two base plates, adjust the top leveling mechanism 3, check whether the weight monitoring and recording system is operating accurately, adjust the position of the ignition mechanism 19 to the predetermined ignition position, adjust the height of the jack 18 and place it in the corresponding position of the base 5 to support the bottom plate of the inner chamber. Note that the top of the jack 18 should be in a state of almost contact with the bottom plate of the inner chamber.

[0080] 2. Pressurize the coal body 12 in the horizontal and vertical directions through multiple pressurizing mechanisms 11. Specifically, inject piston fluid 27 into the horizontal and vertical piston chambers at a constant pressure simultaneously through an external constant pressure pump. The injection pressure is the in-situ stress of the coal seam set in the experiment. When the constant pressure pump reaches the target value, close the valve and stop the constant pressure pump. After the pressure loading is completed, check the air tightness of the system. After the air tightness is good, use a vacuum pump to perform vacuum treatment. After the treatment is completed, proceed to the next step.

[0081] 3. Inject the vaporizing agent into the first cavity through the first injection port 8, and record the data of the horizontal mechanism 3 and the weight acquisition mechanism at the same time.

[0082] Fourth, ignite the coal body 12 through the ignition mechanism 19, and determine whether the ignition is complete by the data of the horizontal mechanism 3 (the ignition is complete when the balance data starts to decrease continuously). Then open the synthesis extraction port 7, collect and store the synthesis gas, stop injecting the gasifying agent after a period of time, and inject helium to stop the gasification reaction.

[0083] 5. Extract the morphological features of the first cavity. Specifically, after the gasification reaction stops and the cavity cools to room temperature, open the bottom base 5 of the outer chamber and extract the morphological features of the first cavity using a cave 3D scanning device.

[0084] VI. Combining the macroscopic composition and fracture distribution characteristics of the original coal body with data from the horizontal mechanism 3 and the weight acquisition mechanism, analyze the spalling characteristics and patterns of coal body 12.

[0085] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0086] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A physical simulation device for dynamic monitoring of coal body stripping in an in-situ UCG process, characterized in that, include: The outer chamber has a sealed first cavity inside, and the outer chamber has an extraction port (7) and a first injection port (8) that are connected to the first cavity. An inner chamber is located within the first cavity, and a semi-open second cavity is provided inside the inner chamber for placing coal (12). A horizontal mechanism (3) is installed on the outer chamber and is connected to the inner chamber. The horizontal mechanism (3) collects the weight change curves of the inner chamber and the coal body (12) in real time. Multiple pressurizing mechanisms (11) are provided on the inner chamber, and the multiple pressurizing mechanisms (11) are used to pressurize the coal body (12) in the horizontal and vertical directions; A weight acquisition mechanism is located at the bottom of the first cavity, and the open end of the second cavity faces the weight acquisition mechanism. The weight acquisition mechanism includes a weight monitoring integrator (9) and a plurality of miniature gravity sensors (10) disposed on the weight monitoring integrator (9). An ignition mechanism (19) is provided on the outer chamber and is used to ignite the coal body (12); During the simulation, the thermal spalling patterns of different types of coal were explored by using the horizontal mechanism (3) and monitoring the weight changes, spalling locations and weight characteristics of the coal body (12).

2. The physical simulation device for dynamic monitoring of coal body stripping in the in-situ UCG process according to claim 1, characterized in that, The external warehouse includes: The first compartment (2) is open at one end; The base (5) is detachably connected to the open end of the first compartment (2) by a plurality of fixing bolts (6), and the first compartment (2) and the base (5) form the first cavity.

3. The physical simulation device for dynamic monitoring of coal body stripping in the in-situ UCG process according to claim 2, characterized in that, The inner warehouse includes: The top plate (4) is connected to the horizontal mechanism (3); Multiple side plates (15) are connected to the top plate (4); Multiple base plates (16) are detachably connected to multiple side plates (15) by multiple fixing bolts (6), and the top plate (4), multiple side plates (15) and multiple base plates (16) form the second cavity; Multiple pressurizing mechanisms (11) are respectively disposed on multiple side plates and multiple bottom plates (16).

4. The physical simulation device for dynamic monitoring of coal body stripping in the in-situ UCG process according to claim 3, characterized in that, Multiple jacks (18) are provided between the base plate and the base.

5. The physical simulation device for dynamic monitoring of coal body stripping in the in-situ UCG process according to claim 1, characterized in that, The pressurizing mechanism (11) includes: Multiple piston chambers are connected to pistons (25) via piston fluid (27) inside, and a second injection port (21) is provided at one end of each piston chamber. The pressure application plate (23) is connected to the pistons (25) via multiple pressure-bearing columns (24), and the pressure application plate (23) is used to abut against the coal body (12).

6. The physical simulation device for dynamic monitoring of coal seam stripping in the in-situ UCG process according to claim 5, characterized in that, The outer compartment is provided with a plurality of third injection ports (17), which are connected to a plurality of second injection ports (21).

7. The physical simulation device for dynamic monitoring of coal body stripping in the in-situ UCG process according to claim 2, characterized in that, A first sealing ring (14) is provided between the first cabin (2) and the base (5).

8. The physical simulation device for dynamic monitoring of coal seam stripping in the in-situ UCG process according to claim 5, characterized in that, A second sealing ring (26) is provided between the pressure application plate (23) and the pressure-bearing column (24).

9. The physical simulation device for dynamic monitoring of coal body stripping in the in-situ UCG process according to claim 1, characterized in that, It also includes a support frame (1) connected to the outer compartment.

10. A physical simulation method for dynamic monitoring of coal body spalling in an in-situ UCG process, based on the physical simulation device for dynamic monitoring of coal body spalling in an in-situ UCG process as described in any one of claims 1-9, characterized in that, include: Prepare the coal body (12) and place the coal body (12) into the second cavity; The coal body (12) is pressurized in both horizontal and vertical directions by a plurality of the pressurizing mechanisms (11); A vaporizing agent is injected into the first cavity through the first injection port (8), while the data of the horizontal mechanism (3) and the weight acquisition mechanism are recorded. The coal body (12) is ignited by the ignition mechanism (19); Extract the morphological features of the first cavity; Based on the original macroscopic composition and fracture distribution characteristics of the coal body, and the data from the horizontal mechanism (3) and weight acquisition mechanism, the spalling characteristics and patterns of the coal body (12) are analyzed.

Images