Device for simulating in-situ dry distillation of underground coal

Abstract

The invention discloses a device for simulating underground coal in-situ dry distillation. The device comprises an experiment machine table, a reactor, a bearing box, a pressure control system, an inner pressurization mechanism, a stress assembly and a gas treatment system, the reactor is installed on the experiment machine table, a bearing box and a heating system are arranged in the reactor, the pressure control system is arranged above the bearing box, a plurality of inner pressurization mechanisms are evenly distributed in the bearing box, a stress assembly is arranged below the bearing box, and the gas treatment system is arranged on the reactor. The bearing box is used for bearing a coal sample; the heating system is used for providing temperature conditions required by the device; the pressure control system is matched with the plurality of inner pressurizing mechanisms and is used for compacting the coal sample and forming a gas flowing gap in the coal; the stress assembly is used for providing internal stress for the coal sample; and the gas treatment system is used for collecting and analyzing gas in the dry distillation product. The device can simulate the stress change in the underground coal seam, and ensures the sufficient flow of gas in dry distillation.

Description

Technical Field

[0001] The present invention relates to the technical field of coal dry distillation simulation equipment, in particular to a device for simulating in-situ dry distillation of underground coal. Background Art

[0002] Underground coal in-situ dry distillation is carried out under high temperature and pressure. Experimental simulations allow for in-depth study of the pyrolysis and transformation of coal under varying temperature, pressure, and atmosphere conditions. This allows for the investigation of the reaction mechanisms, kinetics, and product formation patterns of coal dry distillation, as well as their relationship to coal quality. However, most existing equipment used to simulate underground coal dry distillation directly uses pressurization and heating to pyrolyze and transform coal samples. This method fails to accurately reproduce underground pressure and environmental conditions, making it difficult for experimental equipment to accurately capture the composition of the atmosphere and gas production patterns.

[0003] Therefore, overcoming the defects of the prior art is a technical problem that needs to be solved urgently in this technical field. Summary of the Invention

[0004] In view of the above problems, the present invention provides a device for simulating in-situ dry distillation of underground coal.

[0005] The purpose of the present invention can be achieved through the following solutions:

[0006] The present invention provides a device for simulating underground coal in-situ dry distillation, comprising: an experimental machine, a reactor, a carrying box, a pressure control system, an internal pressurizing mechanism, a stress component and a gas processing system;

[0007] The reactor is installed on the experimental machine, the carrying box and the heating system are arranged in the reactor, the pressure control system is arranged above the carrying box, a plurality of internal pressurizing mechanisms are evenly distributed in the carrying box, a stress component is arranged below the carrying box, and the gas treatment system is arranged on the reactor;

[0008] The carrying box is used to carry coal samples; the heating system is used to provide the temperature conditions required by the device; the pressure control system and the multiple internal pressurization mechanisms cooperate to compact the coal samples and form gaps inside the coal for gas flow; the stress component is used to provide internal stress to the coal samples; and the gas processing system is used to collect and analyze the gas in the distillation products.

[0009] Furthermore, the pressure control system includes: a connecting rod, a threaded rod, a driving motor, an upper plate, a lower pressure plate and an inner plate;

[0010] The connecting rod is transversely fixed in the reactor, the threaded rod is arranged parallel to and below the connecting rod, the upper frame is slidably arranged on the connecting rod, and the upper frame is slidably connected to the threaded rod through threaded engagement; the driving motor is arranged on the side of the reactor, and the output end of the driving motor is fixed to the threaded rod;

[0011] A plurality of lower pressing plates are arranged along the length direction below the upper frame plate, and the lower pressing plates are telescopically connected to the upper frame plate through symmetrically arranged first support rods;

[0012] A plurality of inner plates are arranged in parallel below the lower pressing plate, and the inner plates are telescopically connected to the upper frame plate through symmetrically arranged second support rods.

[0013] Furthermore, the upper plate is provided with a first hydraulic cylinder and a second hydraulic cylinder;

[0014] One end of the first support rod is fixed to the lower pressing plate, and the other end is connected to the telescopic end of the first hydraulic cylinder;

[0015] One end of the second support rod is fixed to the inner plate, and the other end is connected to the telescopic end of the second hydraulic cylinder.

[0016] Furthermore, the internal pressurization mechanism includes: a positioning shaft and a pressurizing sleeve; the positioning shaft is vertically fixed in the carrying box, and a plurality of pressurizing sleeves are arranged on the positioning shaft.

[0017] Furthermore, a fixing rod is movably provided in the positioning shaft rod through an internal spring, and a ring sleeve is fixedly sleeved on the fixing rod;

[0018] A plurality of side pressure plates are distributed on the outer circumference of the pressurized sleeve; an inner shaft frame is hinged on the positioning shaft, and the cross-section of the inner shaft frame is an X-shaped structure; the inner lower end of the inner shaft frame is hinged on the positioning shaft, and the inner upper end of the inner shaft frame is hinged to the ring sleeve; a connecting shaft is slidably provided on the side pressure plate, and the outer upper end and the outer lower end of the inner shaft frame are rotatably connected to the connecting shaft respectively.

[0019] Furthermore, an outer reinforcement plate is detachably provided on the side pressure plate, and the length of the outer reinforcement plate located on the relatively lower pressure sleeve is smaller than the length of the outer reinforcement plate located on the relatively upper pressure sleeve.

[0020] Furthermore, when the inner plate is in contact with the fixing rod, the lower pressing plate contacts the coal sample after or simultaneously with the inner plate.

[0021] Furthermore, the stress component includes:

[0022] Outer shaft seat;

[0023] An inner shaft cylinder is fixed at the center of the outer shaft seat, and a top block is coaxially arranged above the inner shaft cylinder;

[0024] An inner ring cylinder is sleeved and fixed outside the inner shaft cylinder, and an inner top ring is coaxially arranged above the inner ring cylinder;

[0025] The outer ring cylinder is sleeved and fixed outside the inner ring cylinder, and an outer top ring is coaxially arranged above the outer ring cylinder;

[0026] The air flow pipe is connected with the inner shaft cylinder, the inner ring cylinder and the outer ring cylinder through a plurality of branch pipes.

[0027] Furthermore, a piston is slidably provided in the inner shaft cylinder, and the piston is fixed to the top block through a first rack rod; a first ring plug is slidably provided in the inner ring cylinder, and the first ring plug is fixed to the inner top ring through multiple second rack rods; a second ring plug is provided in the outer ring cylinder, and the second ring plug is fixed to the outer top ring through multiple third rack rods.

[0028] Furthermore, the top block, the inner top ring, and the outer top ring can be arranged in a stepped manner or in parallel.

[0029] Compared with the prior art, this application has the following beneficial effects:

[0030] In an embodiment of the present invention, a device for simulating in-situ dry distillation of underground coal is provided. A coal sample is buried in a carrying box. Before the dry distillation reaction of the coal sample, a pressure control system is used in conjunction with an internal pressurization structure to fully compact the coal sample and form a gas flow gap inside the coal sample. This can simulate the stress changes in the underground coal seam, thereby ensuring that the gas can fully flow during the dry distillation of the coal sample, so as to obtain the properties of the target coal sample and the characteristics of the dry distillation process; the setting of the stress component can provide internal stress to the coal sample, thereby simulating changes in the ground pressure environment.

[0031] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1A schematic structural diagram of a device for simulating underground coal in-situ dry distillation provided by an embodiment of the present invention is shown;

[0034] Figure 2 A cross-sectional view of a device for simulating underground in-situ coal dry distillation provided by an embodiment of the present invention is shown;

[0035] Figure 3 A schematic structural diagram of a pressure control system provided by an embodiment of the present invention is shown;

[0036] Figure 4 It shows a schematic structural diagram of the internal pressurization mechanism provided by an embodiment of the present invention;

[0037] Figure 5 A schematic structural diagram of a pressurized sleeve provided in an embodiment of the present invention is shown;

[0038] Figure 6 A schematic structural diagram of a stress component provided by an embodiment of the present invention is shown;

[0039] In the figure, 1. experimental machine; 2. reactor; 21. heating system; 3. pressure control system; 31. connecting rod; 32. threaded rod; 33. drive motor; 34. upper plate; 35. lower pressure plate; 36. first support rod; 37. second support rod; 4. carrying box; 5. internal pressurization mechanism; 51. positioning shaft rod; 52. pressurized shaft sleeve; 53. fixing rod; 54. side pressure plate; 55. inner shaft frame; 6. stress assembly; 61. outer shaft seat; 62. inner shaft cylinder; 63. inner ring cylinder; 64. outer ring cylinder; 65. top block; 66. inner top ring; 67. outer top ring; 68. air flow tube. DETAILED DESCRIPTION

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings 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 making creative efforts shall fall within the scope of protection of the present invention.

[0041] An embodiment of the present invention provides a device for simulating underground coal in-situ dry distillation, comprising: an experimental machine, a reactor, a carrying box, a pressure control system, an internal pressurizing mechanism, a stress component, and a gas processing system;

[0042] The reactor is installed on the experimental machine, the carrying box and the heating system are arranged in the reactor, the pressure control system is arranged above the carrying box, a plurality of internal pressurizing mechanisms are evenly distributed in the carrying box, a stress component is arranged below the carrying box, and the gas treatment system is arranged on the reactor;

[0043] The carrying box is used to carry coal samples; the heating system is used to provide the temperature conditions required by the device; the pressure control system and the multiple internal pressurization mechanisms cooperate to compact the coal samples and form gaps inside the coal for gas flow; the stress component is used to provide internal stress to the coal samples; and the gas processing system is used to collect and analyze the gas in the distillation products.

[0044] In an embodiment of the present invention, a device for simulating in-situ dry distillation of underground coal is provided. A coal sample is buried in a carrying box. Before the dry distillation reaction of the coal sample, a pressure control system is used in conjunction with an internal pressurization structure to fully compact the coal sample and form a gas flow gap inside the coal sample. This can simulate the stress changes in the underground coal seam, thereby ensuring that the gas can fully flow during the dry distillation of the coal sample, so as to obtain the properties of the target coal sample and the characteristics of the dry distillation process; the setting of the stress component can provide internal stress to the coal sample, thereby simulating changes in the ground pressure environment.

[0045] The device for simulating underground coal in-situ dry distillation provided by the embodiment of the present invention specifically includes the following contents in the experiment:

[0046] Sample preparation: Coal distillation experiments require the selection of appropriate coal samples and corresponding sample preparation; sample preparation can include operations such as grinding, crushing, and screening of coal samples to obtain coal samples suitable for the experiment.

[0047] Temperature: Coal distillation simulation needs to be conducted within a certain temperature range, typically between 300°C and 900°C. The specific distillation temperature can be selected based on the research objectives and the actual conditions being simulated. The temperature conditions are provided by the heating system 21.

[0048] Pressure: Coal distillation simulation can be carried out under different pressure conditions, including atmospheric pressure, reduced pressure, and high pressure conditions. The pressure can be selected from the pressure conditions in the underground environment. The pressure conditions are provided by the pressure control system (3) and the internal pressure boosting mechanism (5).

[0049] Analytical methods: After the coal distillation simulation is completed, the generated gas, liquid, and solid products need to be analyzed. Common analytical methods include gas chromatography-mass spectrometry (GC-MS), liquid chromatography (LC), infrared spectroscopy (IR), mass spectrometry (MS), etc., to obtain information on the composition and properties of the products.

[0050] In order to specifically illustrate the device for simulating underground coal in-situ dry distillation provided by an embodiment of the present invention, its overall structure will be described below.

[0051] See Figure 2 and Figure 3 In the embodiment of the present invention, the pressure control system 3 includes a connecting rod 31, a threaded rod 32, a driving motor 33, an upper plate 34, a lower pressure plate 35 and an inner plate;

[0052] The connecting rod 31 is transversely fixed in the reactor 2, the threaded rod 32 is arranged in parallel below the connecting rod 31, and the upper frame plate 34 is slidably arranged on the connecting rod 31, and the upper frame plate 34 is slidably connected to the threaded rod 32 by threaded engagement; the driving motor 33 is arranged on the side of the reactor 2, and the output end of the driving motor 33 is fixed to the threaded rod 32; a plurality of the lower pressure plates 35 are arranged along the length direction below the upper frame plate 34, and the lower pressure plates 35 are telescopically connected to the upper frame plate 34 through a symmetrically arranged first support rod 36; a plurality of the inner plates are arranged in parallel below the lower pressure plate 35, and the inner plates are telescopically connected to the upper frame plate 34 through a symmetrically arranged second support rod 37.

[0053] Specifically, a first hydraulic cylinder and a second hydraulic cylinder are provided on the upper plate 34; one end of the first support rod 36 is fixed to the lower pressure plate 35, and the other end is connected to the telescopic end of the first hydraulic cylinder; one end of the second support rod 37 is fixed to the inner plate, and the other end is connected to the telescopic end of the second hydraulic cylinder.

[0054] The pressure control system 3 provided in this embodiment of the present invention rotates the threaded rod 32 through the rotational drive action of the drive motor 33, thereby driving the upper plate 34 to adjust its width. The telescopic end of the first hydraulic cylinder and the corresponding first support rod 36 drive the lower pressure plate 35 to synchronously or asynchronously press down the coal sample, simulating the ground stress and ground pressure effects during actual underground coal distillation. The telescopic end of the second hydraulic cylinder and the corresponding second support rod 37 drive the inner plate into contact with the internal pressurization mechanism 5, thereby controlling the internal pressurization mechanism 5 to increase the internal pressure of the coal sample.

[0055] See Figure 4 and Figure 5 In a preferred embodiment, the internal pressurization mechanism 5 includes: a positioning shaft rod 51 and a pressurizing sleeve 52; the positioning shaft rod 51 is vertically fixed in the carrying box 4, and a plurality of pressurizing sleeves 52 are arranged on the positioning shaft rod 51, wherein each pressurizing sleeve 52 is buried in the coal sample.

[0056] A fixing rod 53 is movably provided in the positioning shaft 51 through an internal spring, and a ring sleeve is fixed on the fixing rod 53; a plurality of side pressure plates 54 are distributed on the outer circumference of the pressurizing sleeve 52; an inner shaft frame 55 is hinged on the positioning shaft 51, and the cross-section of the inner shaft frame 55 is an X-shaped structure; the inner lower end of the inner shaft frame 55 is hinged on the positioning shaft 51, and the inner upper end of the inner shaft frame 55 is hinged to the ring sleeve; a connecting shaft is slidably provided on the side pressure plate 54, and the outer upper end and the outer lower end of the inner shaft frame 55 are respectively rotatably connected to the connecting shaft.

[0057] When the inner plate of the pressure control system 3 is driven to contact the fixed rod 53, the fixed rod 53 compresses the inner spring and moves downward, and the multiple rings on the fixed rod 53 can synchronously move axially downward. At this time, the inner shaft frame 55 expands radially outward and is expanded by multiple side pressure plates 54.

[0058] In this embodiment of the present invention, the cross-section of the side pressure plate 54 consists of a vertical section and two transverse sections, with the two transverse sections arranged in the same direction at either end of the vertical section. The side pressure plate 54 is removably provided with an external reinforcement plate. The external reinforcement plate located on the relatively lower pressure sleeve is shorter than the external reinforcement plate located on the relatively upper pressure sleeve. This allows the side pressure plates 54 at each pressure sleeve 52 to control the pressurization of the coal sample to varying degrees and form a flow gap, thereby simulating the stress changes in underground coal seams.

[0059] This radial pressurization and flow gap design can better simulate the geostress effects in underground coal seams, particularly by promoting the flow of gas and liquid within the coal sample. This helps simulate the material transfer and reactions during coal distillation, bringing the experiment closer to reality. The relatively low internal pressure provided by the pressurized sleeve (the external reinforcement plate is replaceable) can simulate the geostress distribution at different depths and locations in the underground coal seam. The different internal pressure intensities provided by the pressurized sleeves 52 at different depths can more realistically simulate the stress distribution in the underground coal seam.

[0060] In this embodiment of the present invention, during the contact between the inner plate of the pressure control system 3 and the fixed rod 53 of the internal pressurizing mechanism 5, the lower pressure plate 35 contacts the coal sample after or simultaneously with the inner plate. The axial pressurization of the lower pressure plate 35 further enhances the compaction effect of the coal sample. By radially pressurizing the pressure control system 3 while simultaneously applying axial pressure by the internal pressurizing mechanism 5, the coal sample can be made more compact and dense, simulating the compaction effect of an actual dry distillation process. Simultaneously, the stress and stress deformation in the underground coal seam are simulated, resulting in a more realistic simulation of the stress state and deformation conditions in the underground coal seam.

[0061] See Figure 6 In an embodiment of the present invention, the stress component 6 includes:

[0062] Outer shaft seat 61;

[0063] The inner shaft cylinder 62 is fixed at the center of the outer shaft seat 61, and a top block 65 is coaxially arranged above the inner shaft cylinder 62;

[0064] The inner ring cylinder 63 is sleeved and fixed on the outside of the inner shaft cylinder 62. An inner top ring 66 is coaxially arranged above the inner ring cylinder 63.

[0065] The outer ring cylinder 64 is sleeved and fixed outside the inner ring cylinder 63. An outer top ring 67 is coaxially arranged above the outer ring cylinder 64.

[0066] The air flow pipe 68 is connected to the inner shaft cylinder 62 , the inner ring cylinder 63 and the outer ring cylinder 64 through a plurality of branch pipes.

[0067] In a preferred embodiment, a piston is slidably disposed within the inner shaft cylinder 62 and secured to the top block 65 via a first support rod. A first ring plug is slidably disposed within the inner ring cylinder 63 and secured to the inner top ring 66 via a plurality of second support rods. A second ring plug is disposed within the outer ring cylinder 64 and secured to the outer top ring 67 via a plurality of third support rods. Compression springs are disposed between the top block 65, the inner top ring 66, and the outer top ring 67.

[0068] In an embodiment of the present invention, the top block 65, the inner top ring 66, and the outer top ring 67 can be arranged in a stepped or parallel manner. The top block 65, the inner top ring 66, and the outer top ring 67 in the stress assembly 6 can be preferentially arranged and sized before the pressure control system 3 operates. The top block 65, the inner top ring 66, and the outer top ring 67 can provide additional internal support. When the lower pressure plate 35 in the pressure control system 3 presses down on the coal sample, the stepped arrangement formed by the top block 65, the inner top ring 66, and the outer top ring 67 can form a conical support effect, so that the pressure on the coal sample is applied to a smaller area, destroying the center of the coal sample, thereby studying the effects of local pressure on coal distillation reactions, product distribution, and other aspects. Adjustments can also be made to form an inverted conical support effect to obtain experimental data related to pressure distribution, sample deformation, and the like.

[0069] Specifically, the selected coal sample can be placed in a carrying box 4 and undergo necessary pre-processing, such as crushing and grinding, to obtain a coal sample that meets the experimental requirements. Based on the research objectives, experimental conditions, including temperature, pressure, and retorting time, are set. These conditions can be set based on the actual conditions of coal retorting and the expected reaction process. By controlling the pressure control system 3 in conjunction with the internal pressurization mechanism 5, the required pressure is applied to simulate the underground stress environment. During the experiment, data on key parameters such as temperature, pressure, and reaction time are regularly collected and recorded. Appropriate sensors and monitoring equipment can be used for data collection. After the retorting process is completed, the sample is removed and analyzed and characterized accordingly to evaluate the influencing factors and patterns of the retorting reaction.

[0070] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 limiting the present invention.

[0071] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0072] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0073] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0074] In the description of the present invention, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In the present invention, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine different embodiments or examples described in the present invention and features of different embodiments or examples without contradiction.

[0075] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for simulating in-situ dry distillation of underground coal, characterized in that: include: Experimental machine (1), reactor (2), carrying box (4), pressure control system (3), internal pressurization mechanism (5), stress component (6) and gas treatment system; The reactor (2) is mounted on the experimental machine (1); the carrying box (4) and the heating system (21) are arranged in the reactor (2); the pressure control system (3) is arranged above the carrying box (4); a plurality of internal pressurizing mechanisms (5) are evenly distributed in the carrying box (4); a stress component (6) is arranged below the carrying box (4); and the gas treatment system is arranged on the reactor (2); The carrying box (4) is used to carry coal samples; the heating system is used to provide the temperature conditions required by the device; the pressure control system (3) and the plurality of internal pressurization mechanisms (5) cooperate to compact the coal samples and form gaps for gas flow inside the coal; the stress component (6) is used to provide internal stress to the coal samples; and the gas processing system is used to collect and analyze the gas in the dry distillation product.

2. The device according to claim 1, characterized in that The pressure control system comprises: a connecting rod (31), a threaded rod (32), a driving motor (33), an upper plate (34), a lower pressure plate (35) and an inner plate; The connecting rod (31) is transversely fixed in the reactor (2), the threaded rod (32) is arranged parallel to the bottom of the connecting rod (31), the upper frame plate (34) is slidably arranged on the connecting rod (31), and the upper frame plate (34) is slidably connected to the threaded rod (32) through threaded engagement; the driving motor (33) is arranged on the side of the reactor (2), and the output end of the driving motor (33) is fixed to the threaded rod (32); A plurality of lower pressing plates (35) are arranged along the length direction below the upper frame plate (34), and the lower pressing plates (35) are telescopically connected to the upper frame plate (34) via symmetrically arranged first support rods (36); A plurality of inner plates are arranged in parallel below the lower pressing plate (35), and the inner plates are telescopically connected to the upper frame plate (34) via symmetrically arranged second support rods (37).

3. The device according to claim 2, characterized in that The upper frame plate (34) is provided with a first hydraulic cylinder and a second hydraulic cylinder; One end of the first support rod (36) is fixed to the lower pressing plate (35), and the other end is connected to the telescopic end of the first hydraulic cylinder; One end of the second support rod (37) is fixed to the inner plate, and the other end is connected to the telescopic end of the second hydraulic cylinder.

4. The device according to claim 2, characterized in that The internal pressurization mechanism (5) comprises: a positioning shaft (51) and a pressurizing shaft sleeve (52); the positioning shaft (51) is vertically fixed in the carrying box (4), and a plurality of pressurizing shaft sleeves (52) are arranged on the positioning shaft (51).

5. The device according to claim 4, characterized in that A fixing rod (53) is movably provided in the positioning shaft (51) via an internal spring, and a ring sleeve is fixedly sleeved on the fixing rod (53); The pressurized sleeve (52) is provided with a plurality of side pressure plates (54) distributed on the outer circumference; an inner shaft frame (55) is hinged on the positioning shaft (51), and the cross section of the inner shaft frame (55) is an X-shaped structure; the inner lower end of the inner shaft frame (55) is hinged on the positioning shaft (51), and the inner upper end of the inner shaft frame (55) is hinged to the ring sleeve; a connecting shaft is slidably provided on the side pressure plate (54), and the outer upper end and the outer lower end of the inner shaft frame (55) are respectively rotatably connected to the connecting shaft.

6. The device according to claim 5, characterized in that The side pressure plate (54) is detachably provided with an external reinforcement plate, and the length of the external reinforcement plate located on the relatively lower pressure shaft sleeve is smaller than the length of the external reinforcement plate located on the relatively upper pressure shaft sleeve.

7. The device according to claim 5, characterized in that When the inner plate is in contact with the fixing rod (53), the lower pressing plate (35) contacts the coal sample later than or simultaneously with the inner plate.

8. The device according to claim 1, characterized in that The stress component (6) comprises: Outer shaft seat (61); An inner shaft cylinder (62) is fixed at the center of the outer shaft seat (61), and a top block (65) is coaxially arranged above the inner shaft cylinder (62); An inner ring cylinder (63) is sleeved and fixed on the outside of the inner shaft cylinder (62), and an inner top ring (66) is coaxially arranged above the inner ring cylinder (63); An outer ring cylinder (64) is sleeved and fixed outside the inner ring cylinder (63), and an outer top ring (67) is coaxially arranged above the outer ring cylinder (64); The air flow pipe (68) is connected to the inner shaft cylinder (62), the inner ring cylinder (63) and the outer ring cylinder (64) through a plurality of branch pipes.

9. The device according to claim 8, characterized in that A piston is slidably provided in the inner shaft cylinder (62), and the piston is fixed to the top block (65) through a first rack rod; a first ring plug is slidably provided in the inner ring cylinder (63), and the first ring plug is fixed to the inner top ring (66) through a plurality of second rack rods; a second ring plug is provided in the outer ring cylinder (64), and the second ring plug is fixed to the outer top ring (67) through a plurality of third rack rods.

10. The device according to claim 9, characterized in that The top block (65), the inner top ring (66), and the outer top ring (67) can be arranged in a stepped manner or in parallel.

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