Dynamic monitoring physical simulation device and method for coal body stripping in in-situ UCG process

Abstract

The invention relates to the technical field of coal underground gasification, and discloses an in-situ UCG process coal body stripping dynamic monitoring physical simulation device and method.A sealed first cavity is formed in an outer bin, and an extraction opening and a first injection opening communicating with the first cavity are formed in the outer bin; a semi-open second cavity is formed in the inner bin, and coal is placed in the second cavity; the horizontal mechanism is arranged on the outer bin and connected with the inner bin; the pressurizing mechanisms are arranged on the inner bin and used for pressurizing the coal body in the horizontal direction and the vertical direction; the weight collecting mechanism is arranged at the bottom of the first cavity, and the open end of the second cavity faces the weight collecting mechanism; according to the coal body stripping characteristic monitoring device, the coal body stripping characteristic in the coal underground gasification process can be monitored in real time, and the control effect of a coal composition on stripping can be analyzed by combining a coal composition and structure space characteristic characterization technology.

Description

Technical Field

[0001] The invention relates to the technical field of underground coal gasification, and in particular to a physical simulation device and method for dynamic monitoring of coal body spalling during an in-situ UCG process. Background Art

[0002] UCG involves different processes such as drying, pyrolysis, chemical reaction and mechanical action, which is the main driver of gasification cavity development. Among them, coal spalling is one of the cavity growth mechanisms during underground coal gasification, which is caused by the interconnection of cracks developed in the coal seam, resulting in the shedding of small coal particles from the coal seam. It plays an important role by providing a higher surface area to improve performance. At present, the mechanism of spalling and its characterization are still unclear, and there is no perfect experimental technology to measure and monitor the dynamic spalling characteristics of coal. In addition, due to the heterogeneity of coal, there are significant differences in spalling behavior, which seriously restricts the development of UCG gasification cavity stability evaluation, stabilization technology, process control technology and other technologies. Therefore, physical simulation of dynamic monitoring of coal spalling in the in-situ UCG process is of great significance for the application of medium-deep underground coal gasification projects. Summary of the invention

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

[0004] To achieve the above object, the present invention provides the following solution: The present invention provides a physical simulation device for dynamic monitoring of coal spalling during an in-situ UCG process, comprising:

[0005] An outer chamber, wherein a sealed first cavity is provided inside, and a suction port and a first injection port connected to the first cavity are provided on the outer chamber;

[0006] An inner bin is arranged in the first cavity, a semi-open second cavity is arranged inside the inner bin, and the second cavity is used for placing coal;

[0007] A horizontal mechanism is arranged on the outer bin, and the horizontal mechanism is connected to the inner bin;

[0008] A plurality of pressurizing mechanisms are arranged on the inner bin, and the plurality of pressurizing mechanisms are used to pressurize the coal body in horizontal and vertical directions;

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

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

[0011] Optionally, the outer warehouse includes:

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

[0013] The base is detachably connected to the open end of the first chamber body through a plurality of fixing bolts, and the first chamber body is formed between the first chamber body and the base.

[0014] Optionally, the inner warehouse includes:

[0015] A top plate connected to the horizontal mechanism;

[0016] A plurality of side panels connected to the top panel;

[0017] A plurality of bottom plates are detachably connected to the plurality of side plates via a plurality of fixing bolts, and the second cavity is formed between the top plate, the plurality of side plates and the plurality of bottom plates;

[0018] The plurality of pressurizing mechanisms are respectively disposed on the plurality of side plates and the plurality of bottom plates.

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

[0020] Optionally, the pressurizing mechanism includes:

[0021] A plurality of piston chambers, each of which is connected to a piston by piston fluid drive, and a second injection port is provided at one end of the piston chamber;

[0022] A pressure applying plate is connected to the plurality of pistons via a plurality of pressure bearing columns, and the pressure applying plate is used to resist against the coal body.

[0023] Optionally, a plurality of third injection ports are provided on the outer chamber, and the plurality of third injection ports are connected to the 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 application plate and the pressure bearing column.

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

[0027] The present invention also provides a physical simulation method for dynamic monitoring of coal spalling during an in-situ UCG process, comprising:

[0028] preparing the coal body and placing the coal body in the second cavity;

[0029] Pressurizing the coal body in horizontal and vertical directions by using a plurality of pressurizing mechanisms;

[0030] injecting a gasifying agent into the first cavity through the first injection port, and recording data of the horizontal mechanism and the weight collection mechanism at the same time;

[0031] igniting the coal body by the ignition mechanism;

[0032] Extracting the first cavity morphology feature;

[0033] The coal body spalling characteristics and laws are analyzed by combining the original coal body macroscopic composition and crack distribution characteristics with the horizontal mechanism and weight collection mechanism data.

[0034] The present invention discloses the following technical effects: by placing the coal body in the second cavity, the in-situ UCG process can be simulated through the first injection port, multiple pressurizing mechanisms and the weight collection mechanism ignition mechanism, and in the simulation process, the thermal spalling law of different types of coal is explored through the horizontal mechanism and monitoring of the weight change of the coal body, the position and weight characteristics of the spalling, the spalling characteristics of the coal body during underground coal gasification are monitored in real time, and the control of the coal structure on spalling can be analyzed in combination with the coal composition and structural space feature characterization technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

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

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

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

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

[0040] In the figure: 1. support frame; 2. first cabin; 3. horizontal mechanism; 4. top plate; 5. base; 6. fixing screws; 7. extraction port; 8. first injection port; 9. weight monitoring integrator; 10. micro gravity sensor; 11. pressurizing 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 column; 25. piston; 26. second sealing ring; 27. piston fluid. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments 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.

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Reference Figure 1-Figure 4 The present invention provides a physical simulation device for dynamic monitoring of coal spalling during an in-situ UCG process, comprising:

[0044] The outer chamber has a sealed first cavity inside, and is provided with 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 later inject helium;

[0045] An inner chamber is arranged in the first cavity, and a semi-open second cavity is arranged inside the inner chamber, and the second cavity is used to place the coal body 12;

[0046] A horizontal mechanism 3 is arranged on the outer bin, and the horizontal mechanism 3 is connected to the inner bin;

[0047] A plurality of pressurizing mechanisms 11 are arranged on the inner bin, and the plurality of pressurizing mechanisms 11 are used to pressurize the coal body 12 in the horizontal and vertical directions;

[0048] A weight collection mechanism is disposed at the bottom of the first cavity, and the open end of the second cavity faces the weight collection mechanism;

[0049] The ignition mechanism 19 is disposed on the outer bin and is used to ignite the coal body 12 .

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

[0051] Furthermore, the weight collection mechanism includes a weight monitoring integrator 9 and a plurality of miniature gravity sensors 10 arranged on the weight monitoring integrator. The number of the miniature gravity sensors 10 is specifically 100 and they are evenly distributed. The sensor accuracy is ±0.001g. Each sensor is equipped with a high-temperature resistant cover layer on the top, which is connected to an external computer and can record the weight change characteristics of each sensor in real time. The size of the weight monitoring integrator 9 is 10*10*5cm.

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

[0053] Furthermore, the size of the first cavity is 50*40*40cm.

[0054] Furthermore, the size of the second cavity is 40*30*20cm.

[0055] Furthermore, the size of the coal body 12 is 40*30*20 cm, and the coal body needs to be polished and smooth before being placed. When in use, an external lifting device is required to lift the coal body 12 to a specified position.

[0056] In one embodiment of the present invention, the outer compartment comprises:

[0057] A first cabin 2, one end of which is open;

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

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

[0060] A top plate 4 connected to the horizontal mechanism 3;

[0061] A plurality of side panels 15 connected to the top panel 4;

[0062] A plurality of bottom plates 16 are detachably connected to the plurality of side plates 15 via a plurality of fixing bolts 6, and a second cavity is formed between the top plate 4, the plurality of side plates 15 and the plurality of bottom plates 16;

[0063] The plurality of pressurizing mechanisms 11 are respectively disposed on the plurality of side plates 15 and the plurality of bottom plates 16 .

[0064] The side plate 15 and the bottom plate 16 are both provided with bolt holes 22 for assembling the fixing screws 6 .

[0065] The size of the bottom plate is 40*15*5cm, of which the size of the part in contact with the bottom of the coal body 12 is 40*10*5cm.

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

[0067] In one embodiment of the present invention, a plurality of jacks 18 are arranged between the bottom plate and the base. The controllable height range of the jacks 18 is 8 to 12 cm, and the control accuracy is ±0.1 cm. The jacks 18 are used to support the bottom plate of the inner bin. Note that the top of the jack 18 and the bottom plate of the inner bin should be in a state of being about to contact 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 comprises:

[0069] A plurality of piston chambers, each of which is connected to a piston 25 driven by a piston fluid 27, and a second injection port 21 is provided at one end of the piston chamber;

[0070] The pressure applying plate 23 is connected to a plurality of pistons 25 via a plurality of pressure bearing columns 24 , and the pressure applying plate 23 is used to abut against the coal body 12 .

[0071] Each pressurizing mechanism 11 is provided with three piston chambers.

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

[0073] There are specifically six third injection ports 17 , three of which are respectively disposed on the left and right side walls of the outer chamber, for injecting piston fluid 27 into the second injection port 21 .

[0074] In one embodiment of the present invention, a first sealing ring 14 is disposed 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 applying plate 23 and the pressure bearing column 24 .

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

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

[0078] The present invention also provides a physical simulation method for dynamic monitoring of coal spalling during an in-situ UCG process, comprising:

[0079] 1. Prepare the coal body 12 and place the coal body 12 in the second cavity. Specifically, first select the coal body 12 with a complete coal body structure, use the wire cutting instrument to prepare a rectangular coal body 12 with a size of 40*30*20cm, and polish it to be smooth and flat. Use the CT scanning equipment to perform grayscale scanning on the selected coal body 12 to characterize the macroscopic coal rock composition and crack space distribution characteristics of the coal body 12, and apply bamboo dye at the predetermined ignition position. Use the lifting device to lift the coal body 12 to the appropriate position of the inner warehouse in a certain direction, then install two bottom plates, debug the top horizontal mechanism 3, check whether the weight monitoring and recording system is running accurately, adjust the position of the ignition mechanism 19 to the predetermined ignition position, adjust the height of the jack 18 and place it at the corresponding position of the base 5 to support the bottom plate of the inner warehouse. Note that the top of the jack 18 should be in a state of being in contact with the bottom plate of the inner warehouse;

[0080] Second, the coal body 12 is pressurized in the horizontal and vertical directions by multiple pressurizing mechanisms 11. Specifically, piston fluid 27 is injected into the horizontal and vertical piston chambers at a constant pressure by an external constant pressure pump. The injection pressure is the in-situ stress of the coal seam set in the experiment. When the pressure of the constant pressure pump reaches the target value, the valve is closed and the constant pressure pump is stopped at the same time. After the pressure loading is completed, the air tightness of the system is checked. After the air tightness is intact, a vacuum pump is used for vacuum treatment. After the treatment is completed, the next step is carried out;

[0081] 3. Injecting the gasifying agent into the first cavity through the first injection port 8, while recording the data of the horizontal mechanism 3 and the weight collection mechanism;

[0082] Fourth, the coal body 12 is ignited by the ignition mechanism 19, and the data of the horizontal mechanism 3 is used to determine whether the ignition is completed (the ignition is completed when the balance data starts to decrease continuously), and then the synthesis extraction port 7 is opened, and the synthesis gas is collected and stored. After a period of experiment, the injection of gasification agent is stopped, and helium is injected to stop the gasification reaction;

[0083] 5. Extracting the morphological features of the first cavity. Specifically, after the gasification reaction stops and the cavity is cooled to room temperature, the bottom substrate 5 of the outer chamber is opened, and the morphological features of the first cavity are extracted by a cave three-dimensional scanning device;

[0084] 6. Combine the original coal body macroscopic composition and crack distribution characteristics with the horizontal mechanism 3 and the weight collection mechanism data to analyze the coal body 12 spalling characteristics and laws.

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

[0086] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A physical simulation device for dynamic monitoring of coal spalling during in-situ UCG process, characterized in that: include: An outer chamber, wherein a sealed first cavity is provided inside, and the outer chamber is provided with an extraction port (7) and a first injection port (8) which are connected to the first cavity; An inner chamber is arranged in the first cavity, a semi-open second cavity is arranged inside the inner chamber, and the second cavity is used to place coal (12); A horizontal mechanism (3) is arranged on the outer bin, and the horizontal mechanism (3) is connected to the inner bin; A plurality of pressurizing mechanisms (11) are arranged on the inner bin, and the plurality of pressurizing mechanisms (11) are used to pressurize the coal body (12) in the horizontal and vertical directions; A weight collection mechanism is disposed at the bottom of the first cavity, and the open end of the second cavity faces the weight collection mechanism; An ignition mechanism (19) is arranged on the outer bin, and the ignition mechanism (19) is used to ignite the coal body (12).

2. The physical simulation device for dynamic monitoring of coal spalling during in-situ UCG process according to claim 1 is characterized in that: The outer warehouse comprises: A first cabin (2) having one end open; The base (5) is detachably connected to the open end of the first cabin (2) via a plurality of fixing bolts (6), and the first cavity is formed between the first cabin (2) and the base (5).

3. The physical simulation device for dynamic monitoring of coal spalling during in-situ UCG process according to claim 2 is characterized in that: The inner warehouse comprises: A top plate (4) connected to the horizontal mechanism (3); A plurality of side panels (15) connected to the top panel (4); A plurality of bottom plates (16) are detachably connected to the plurality of side plates (15) via a plurality of fixing bolts (6), and the second cavity is formed between the top plate (4), the plurality of side plates (15) and the plurality of bottom plates (16); The plurality of pressurizing mechanisms (11) are respectively arranged on the plurality of side plates and the plurality of bottom plates (16).

4. The physical simulation device for dynamic monitoring of coal spalling during in-situ UCG process according to claim 3 is characterized in that: A plurality of jacks (18) are arranged between the bottom plate and the base.

5. The physical simulation device for dynamic monitoring of coal spalling during in-situ UCG process according to claim 1 is characterized in that: The pressurizing mechanism (11) comprises: A plurality of piston chambers, each chamber is connected to a piston (25) driven by a piston fluid (27), and a second injection port (21) is provided at one end of the piston chamber; The pressure applying plate (23) is connected to the plurality of pistons (25) via a plurality of pressure bearing columns (24), and the pressure applying plate (23) is used to abut against the coal body (12).

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

7. The physical simulation device for dynamic monitoring of coal spalling during in-situ UCG process according to claim 2 is 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 spalling during in-situ UCG process according to claim 5 is 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 spalling during in-situ UCG process according to claim 1 is characterized in that: It also comprises a support frame (1) connected to the outer bin.

10. A physical simulation method for dynamic monitoring of coal spalling during in-situ UCG process, based on the physical simulation device for dynamic monitoring of coal spalling during in-situ UCG process according to any one of claims 1 to 9, characterized in that: include: preparing the coal body (12) and placing the coal body (12) in the second cavity; Pressurizing the coal body (12) in horizontal and vertical directions by using a plurality of pressurizing mechanisms (11); injecting a gasifying agent into the first cavity through the first injection port (8), and simultaneously recording data of the horizontal mechanism (3) and the weight collection mechanism; igniting the coal body (12) through the ignition mechanism (19); Extracting the first cavity morphology feature; The spalling characteristics and laws of the coal body (12) are analyzed by combining the original macroscopic composition and crack distribution characteristics of the coal body with the data of the horizontal mechanism (3) and the weight collection mechanism.

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