Coal underground gasification combustion intensified emission device and method based on sound wave excitation

Abstract

The invention discloses a coal underground gasification combustion intensified emission device and method based on sound wave excitation. The device comprises a coaxial composite continuous gas injection pipe and a sound wave emission device at the front end of the coaxial composite continuous gas injection pipe, and the device integrates a controllable sound wave generator, a three-stage amplifier, a linkage adjusting bracket and a composite sensor. Sound wave parameters are fed back and regulated in real time through a sensor, coal wall accumulated dust is directionally and efficiently removed, the gasification reaction is enhanced, and the problems of low gas production efficiency and poor stability in the underground coal gasification process are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underground coal gasification, in particular to a coal underground gasification combustion intensification launching device and method based on sound wave excitation. BACKGROUND

[0002] Underground coal gasification (UCG) is a key feasible technical approach to solve the problem of deep coal resource exploitation in the future, with the characteristics of safety, cleanliness and economy. The core principle of UCG is to convert coal resources in situ into high-calorific-value synthesis gas rich in hydrogen (H2) and methane (CH4) through underground controllable combustion. The generated synthesis gas is first transported to the ground gathering center through pipelines, and then distributed to various industries after purification and separation processes, and finally realizes efficient utilization.

[0003] During the process of underground coal gasification, coal and gasification agent undergo gasification reaction to generate synthesis gas, while at the same time, ash deposits are formed on the surface of the coal body. These ash deposits usually adhere to the surface of the coal body in a molten state and are difficult to fall off by themselves. The presence of ash deposits not only hinders the effective contact of oxygen in the gasification agent with fresh coal body, but also reduces the heat transfer efficiency, thereby adversely affecting the gas production efficiency and stability of underground coal gasification. Chinese patent CN203716950U discloses an "underground gasification equipment", which is connected at the front end with a high-energy sound wave launching device for removing ash deposits generated during underground coal seam gasification, thereby improving the gasification efficiency and the quality of coal gas. This type of sound wave launching device and similar sound wave devices usually radiate sound waves in a divergent mode to the surrounding, resulting in high energy loss and poor ash deposit removal effect. Therefore, it is necessary to optimize the structure of the existing sound wave launching device and control the sound wave field in view of the actual needs of the existing underground coal gasification, to enhance the directivity and concentration of sound wave energy, achieve efficient and directional ash removal, thereby enhancing the gasification reaction intensity and improving the quality of synthesis gas. SUMMARY

[0004] In order to overcome the above-mentioned deficiencies of the prior art, the present application provides a coal underground gasification combustion intensification launching device and method based on sound wave excitation, which can efficiently and directionally remove the ash deposits attached to the surface of the coal body, thereby enhancing the gasification reaction intensity and improving the quality of synthesis gas.

[0005] The technical solution adopted by the present application to solve its technical problems is: The application discloses a coal underground gasification combustion intensification emission device based on acoustic wave excitation, which comprises a coaxial composite continuous gas injection pipe, wherein the coaxial composite continuous gas injection pipe comprises a continuous pipe inner pipe and a continuous pipe outer pipe which are coaxially arranged, a plurality of shunt gas outlet pipes are arranged at the front end of the continuous pipe inner pipe, and an acoustic wave emission device corresponding to the plurality of shunt gas outlet pipes is arranged at the front end of the continuous pipe outer pipe; the acoustic wave emission device comprises a controllable acoustic wave generator, an acoustic wave transmission channel, a three-stage expander and a composite sensor, the three-stage expander is connected with the composite sensor through a three-stage linkage adjustment support, the controllable acoustic wave generator is connected with the three-stage expander through the acoustic wave transmission channel, the three-stage expander precisely controls the acoustic wave emission range and direction of the controllable acoustic wave generator by adjusting the angle of the three-stage linkage adjustment support, and the composite sensor is used for monitoring the gasification reaction state in real time and feeding back the controllable acoustic wave generator and the three-stage linkage adjustment support.

[0006] Preferably, the shunt gas outlet pipes are eight, uniformly distributed around the outlet of the continuous pipe inner pipe, and the shunt angle is 10°.

[0007] Preferably, the acoustic wave emission device is provided with a vibration isolation and explosion-proof base around the periphery for supporting and fixing the acoustic wave emission device.

[0008] Preferably, the diameter ratio of the continuous pipe inner pipe to the continuous pipe outer pipe is 2:5.

[0009] Preferably, the controllable acoustic wave generator has a frequency range of 500 Hz to 5000 Hz and a power range of 500 W to 20 Kw, the output power is adjusted in ten grades, and a conical resonant cavity is used to realize acoustic wave focusing.

[0010] Preferably, the inner wall of the acoustic wave transmission channel is provided with a 2 mm thick metal ceramic plating layer.

[0011] Preferably, the three-stage expander adopts a horn nozzle structure, and the inclination angle ranges from 10°.

[0012] Preferably, the three-stage linkage adjustment support adopts a phase synchronous adjustment mechanical structure combining a central driving gear and a hierarchical driven gear, and the initial emission angle is 10°.

[0013] Preferably, the composite sensor is internally arranged with 5 groups of independent precious metal armored thermocouples, the temperature measurement range is 0 to 1600 DEG C, the gas detection types include H2, CO, O2, CO2 and CH4, and the gas detection accuracy is ±1% FS.

[0014] The application further provides an implementation method of the device, which comprises the following steps: (1) arranging the coal underground gasification combustion intensification emission device based on acoustic wave excitation in a gasification channel through an injection well; (2) Real-time monitoring of the gasification reaction state by a composite sensor, and when the effective gas content in the synthesis gas is less than 60% or the gasification region temperature is less than 500°C, starting the sound wave emission device; (3) Removing the ash layer on the surface of the coal body and strengthening the gasification reaction by adjusting the sound wave frequency, power and emission angle; (4) If the reaction state is still not improved after adjustment, adjusting the gas injection position of the sound wave excitation-based coal underground gasification combustion strengthening emission device to a preset position, performing secondary ignition operation, and starting a new round of coal underground gasification process at the new position.

[0015] Advantages: Compared with the prior art, the present application has the following advantages: (1) Directional concentration of sound wave energy significantly improves ash removal efficiency The present application realizes precise control of the sound wave emission angle and range through the synergistic effect of the three-stage expander and the three-stage linkage adjustment support, changes the sound wave energy from a divergent mode to a directional and concentrated emission mode. This greatly reduces the energy loss in the transmission process, concentrates the sound wave energy on the ash layer on the surface of the coal body, and realizes efficient and directional removal of the ash through enhanced vibration fatigue, sound flow disturbance and cavitation impact and other physical effects.

[0016] (2) Breaking the reaction barrier fundamentally improves the gasification reaction intensity and efficiency The present application can timely expose fresh coal body through efficient ash removal, completely opening the reaction interface between the gasification agent and the coal body. At the same time, the sound flow and turbulent flow effects induced by the sound wave significantly strengthen the heat and mass transfer processes in the reaction region, thereby fundamentally strengthening the gasification reaction intensity and improving the conversion rate and utilization rate of coal resources.

[0017] (3) Intelligent sensing and feedback control for continuous and stable gas production The present application realizes real-time and accurate diagnosis of the gasification reaction state by integrating a composite sensor and establishing a control criterion based on the monitoring data (such as effective gas content and temperature); can automatically trigger and optimize the sound wave emission parameters (such as frequency, power and angle) according to the working condition changes, forming a closed-loop intelligent feedback control system, ensuring that the gasification reaction is always in the efficient range, and greatly improving the stability of the gas production process and the quality of the synthesis gas.

[0018] (4) Compact and integrated structure, high engineering applicability and economy The acoustic wave emitting device of this invention is integrated into the front end of a coaxial composite continuous gas injection pipe, resulting in a compact structural design. This integrated design not only avoids complex external systems but also provides the entire device with excellent mobility and reusability, facilitating relocation as the gas injection point moves. It is highly suitable for the engineering requirements of continuous underground coal gasification production, reducing operational complexity and maintenance costs, and possesses excellent commercial prospects. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Figure 1 This is a schematic diagram of the structure of the acoustically excited underground coal gasification combustion enhancement emission device of the present invention. Figure 2 for Figure 1 A schematic diagram of the radial structure at AA'; Figure 3 for Figure 1 Schematic diagram of the three-stage amplifier; Figure 4 This is a schematic diagram illustrating a scenario where no acoustic emission device is used, as provided in an embodiment of the present invention. Figure 5 This is a schematic diagram illustrating the use of a sound wave emitting device according to an embodiment of the present invention; Figure 6 A schematic diagram illustrating the change in the sound wave emission angle provided in an embodiment of the present invention; Figure 7 This is a schematic diagram illustrating the situation of moving the gas injection position in the combustion zone according to an embodiment of the present invention.

[0021] Figure label: 1. Continuous inner tube; 101. Diverter outlet tube I; 102. Diverter outlet tube II; 103. Diverter outlet tube III; 2. Controllable sound wave generator; 3. Signal control line; 4. Sound wave transmission channel; 5. Three-stage amplifier; 6. Three-stage linkage adjustment bracket; 601. First-stage reflector; 602. First-stage adjustment bracket; 603. Second-stage reflector; 604. Second-stage adjustment bracket; 605. Third-stage reflector; 606. Third-stage adjustment bracket; 7. Composite sensor; 8. Vibration isolation and explosion-proof base; 9. Support component; 11. Continuous outer tube; 12. Coaxial composite continuous gas injection tube. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0023] Example 1: like Figures 1-3 As shown, this embodiment provides a sound-wave-excited underground coal gasification combustion enhancement emission device, including a coaxial composite continuous gas injection pipe 12. The coaxial composite continuous gas injection pipe 12 includes a continuous inner pipe 1 and a continuous outer pipe 11 arranged coaxially. The diameter ratio of the continuous inner pipe 1 to the continuous outer pipe 11 is 2:5. Both the continuous inner pipe 1 and the continuous outer pipe 11 are made of carbon steel, a material well known to those skilled in the art. The front end of the continuous inner pipe 1 is provided with multiple branch gas outlet pipes. There are eight branch gas outlet pipes, which are evenly distributed in a ring around the outlet of the continuous inner pipe 1, with a branching angle of 10°, for uniformly injecting the gasifying agent into the gasification chamber. The front end of the continuous outer pipe 11 is provided with a sound wave excitation device corresponding to the branch gas outlet pipes. The acoustic wave emitting device is surrounded by a vibration-damping and explosion-proof base 8, as is well known to those skilled in the art. The vibration-damping and explosion-proof base 8 supports and fixes the entire acoustic wave emitting device to the front end of the continuous outer tube 11. It employs a composite structure of multi-layer stainless steel corrugated pipe and ceramic fiber insulation layer, as is well known to those skilled in the art, effectively isolating the device's own vibration and preventing potential downhole explosions from damaging the core components of the acoustic wave emitting device. The acoustic wave emitting device includes a controllable acoustic wave generator 2, an acoustic wave transmission channel 4, a three-stage amplifier 5, and a composite sensor 7. The acoustic wave transmission channel 4 and the three-stage amplifier 5 are coaxially arranged with the continuous inner tube 1 and the continuous outer tube 11. The frequency range of the controllable acoustic wave generator 2 is 500 Hz. The output power ranges from 500 W to 20 Kw, with ten levels for precise adjustment. A conical resonant cavity is used to focus the sound waves. The inner wall of the sound wave transmission channel (4) is provided with a 2 mm thick metal-ceramic coating, which can effectively reduce energy loss during sound wave transmission and has excellent high temperature resistance and wear resistance. The three-stage amplifier 5 is connected to the composite sensor 7 through the three-stage linkage adjustment bracket 6. The controllable sound wave generator 2 is connected to the three-stage amplifier 5 through the sound wave transmission channel 4. The three-stage amplifier 5 precisely controls the sound wave emission range and direction of the controllable sound wave generator 2 by adjusting the angle of the three-stage linkage adjustment bracket 6. The composite sensor 7 is used to monitor the gasification reaction state in real time and provide feedback control of the controllable sound wave generator 2 and the three-stage linkage adjustment bracket 6.

[0024] The third-stage expander 5 adopts a horn nozzle structure, and the inclination angle ranges from 10°. The third-stage linkage adjusting support 6 is installed in the third-stage expander 5 by means known to those skilled in the art, and comprises a first-stage reflecting frame 601, a first-stage adjusting frame 602, a second-stage reflecting frame 603, a second-stage adjusting frame 604, a third-stage reflecting frame 605 and a third-stage adjusting frame 606 connected with each other. The first-stage adjusting frame 602, the second-stage adjusting frame 604 and the third-stage adjusting frame 606 are mechanically linked by a transmission system consisting of a central driving gear and sub-stage driven gears known to those skilled in the art, and the transmission system comprises a central driving gear, a first-stage driven gear, a second-stage driven gear and a third-stage driven gear. The central driving gear is engaged with the first-stage and second-stage driven gears at the same time. An intermediate gear is arranged between the second-stage driven gear and the third-stage driven gear to enable them to rotate in the same direction. The first-stage adjusting frame 602 is coaxially fixed with the first-stage driven gear; the second-stage adjusting frame 604 is coaxially fixed with the second-stage driven gear; and the third-stage adjusting frame 606 is coaxially fixed with the third-stage driven gear. When the central driving gear rotates upon receiving a control signal from the ground, it will synchronously drive the third-stage adjusting frames to move at a preset ratio, and the specific preset ratio can be determined by those skilled in the art according to actual conditions, so as to accurately change the angles of the first-stage reflecting frame 601, the second-stage reflecting frame 603 and the third-stage reflecting frame 605 fixed therewith. The linkage design ensures the integrity and accuracy of the sound wave beam when changing direction, and the initial emission angle is set to 10°. The sound wave is reflected by the three reflecting frames in the third-stage expander 5 in turn, and is focused and directionally emitted to the target coal wall.

[0025] The composite sensor 7 is fixedly installed at the front end of the third-stage expander 5, and internally integrates 5 groups of independent noble metal armored thermocouples with a temperature measurement range of 0-1600℃, and is configured with sensors capable of detecting the concentrations of H2, CO, O2, CO2 and CH4 in real time, and the gas detection accuracy is ±1% FS. All signals are output to the ground control system known to those skilled in the art through three / four-wire high-temperature shielding cables.

[0026] Reference Figure 4 and Figure 5 This embodiment illustrates the application of the device of the present application in the initial gasification stage.

[0027] When the acoustic wave emission device is not started, the underground gasification cavity develops slowly, and the ash layer is gradually formed on the surface of the coal body, which hinders the reaction. At this time, the composite sensor 7 continuously monitors the working condition data and transmits it to the ground dispatching center. The control system presets the following trigger threshold: when it is monitored that the total content of effective gases such as H2, CO, CH4 in the synthesis gas is less than 60% for 5 minutes, or the temperature of the gasification area is less than 500℃ for 5 minutes, the system automatically determines that the ash deposition is aggravated, and the acoustic wave ash removal needs to be started.

[0028] Immediately, the control system automatically starts the acoustic wave emission device, and the parameters are set as follows: frequency 1000 Hz, power 10 kW, divergence angle 10°, and the fourth gear output power mode is used. The directional emitted acoustic wave energy acts on the coal wall, and through the comprehensive action of vibration fatigue, acoustic flow disturbance and cavitation impact, the ash layer is effectively removed, and the fresh coal body is exposed. This measure can quickly restore the effective contact between the gasification agent and the coal body, and the acoustic wave can also strengthen the heat and mass transfer behavior of the coal body, so that the gasification reaction rate is improved, and the gasification cavity is rapidly expanded.

[0029] Example 2: Reference Figure 5 and Figure 6 , this embodiment demonstrates the ability of the present application to dynamically optimize according to feedback based on example 1.

[0030] When the acoustic wave device has been running for a period of time, the composite sensor 7 again monitors that the effective gas content falls below 60%, and the temperature has a downward trend. At this time, the system first tries to increase the acoustic wave emission power to 12 kW (fifth gear), but the working condition is not obviously improved (i.e. the effective gas content increases by less than 5%) within 10 minutes. The control system judges accordingly that the coal body at the front of the current gasification cavity has been locally depleted, and needs to guide the reaction to expand in a specific direction (such as the production well direction).

[0031] Therefore, the control system starts the emission angle optimization strategy: by controlling the three-stage linkage adjustment support 6, the overall divergence angle of the acoustic wave is accurately adjusted from 10° to 6°. The reduction of the angle makes the acoustic wave energy more concentrated, like an "acoustic wave drill bit", which acts on the target area in a directional manner, preferentially removes the ash in that direction and strengthens the gasification reaction of the coal body in that place, thereby actively guiding the gasification cavity to extend in the predetermined direction, improving the recovery rate of coal resources.

[0032] Example 3: Reference Figure 6 and Figure 7 , this embodiment demonstrates the coping strategy when the coal resources in the local area are gasified.

[0033] If the data of gas production and temperature in the gasification cavity monitored by the composite sensor 7 does not increase after the adjustment of the emission intensity and emission angle as in the embodiment 2, the control system determines that the coal body around the current gas injection position has been substantially completely reacted.

[0034] At this time, the overall movement of the reaction position needs to be carried out. The specific process is as follows: (1) First, the sound wave emission device and the gas injection are closed.

[0035] (2) Then, through the ground hoisting equipment known to those skilled in the art, the whole set of gas injection and sound wave emission system is withdrawn by a predetermined distance (5-8 meters in this example according to the coal seam thickness and gasification rate) along the gas injection well to the wellhead direction known to those skilled in the art.

[0036] (3) After the equipment is moved and fixed, the secondary ignition is carried out at the new position by injecting the gas fuel known to those skilled in the art such as silane or using other ignition methods.

[0037] (4) After the ignition is successful, the gas injection is restored and the intelligent sound wave control process as described in the embodiment 1 is started to open a new round of efficient and stable underground coal gasification process.

[0038] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification and equivalent change made according to the technical essence of the present application to the above embodiment falls within the protection scope of the present application.

Claims

1. A sound-wave-excited underground coal gasification combustion enhancement emission device, characterized in that: The system includes a coaxial composite continuous gas injection tube (12), which comprises a continuous inner tube (1) and a continuous outer tube (11) arranged coaxially. The inner tube (1) has multiple branch outlet tubes at its front end, and the outer tube (11) has a sound wave emitting device corresponding to the branch outlet tubes at its front end. The sound wave emitting device includes a controllable sound wave generator (2), a sound wave transmission channel (4), a three-stage amplifier (5), and a composite sensor (7). 5) The controllable sound wave generator (2) is connected to the composite sensor (7) through the three-level linkage adjustment bracket (6). The controllable sound wave generator (2) is connected to the three-level amplifier (5) through the sound wave transmission channel (4). The three-level amplifier (5) precisely controls the sound wave emission range and direction of the controllable sound wave generator (2) by adjusting the angle of the three-level linkage adjustment bracket (6). The composite sensor (7) is used to monitor the gasification reaction status in real time and provide feedback control to the controllable sound wave generator (2) and the three-level linkage adjustment bracket (6).

2. The acoustic-excited underground coal gasification combustion enhancement emission device according to claim 1, characterized in that: There are eight diversion outlet pipes, which are evenly distributed in a ring around the outlet of the continuous inner pipe (1), with a diversion angle of 10°.

3. The acoustically excited underground coal gasification combustion enhancement emission device according to claim 1, characterized in that: The acoustic wave emitting device is surrounded by a vibration-damping and explosion-proof base (8) for supporting and fixing the acoustic wave emitting device.

4. The acoustically excited underground coal gasification combustion enhancement emission device according to claim 1, characterized in that: The diameter ratio of the inner tube (1) to the outer tube (11) of the continuous tube is 2:

5.

5. The acoustically excited underground coal gasification combustion enhancement emission device according to claim 1, characterized in that: The controllable sound wave generator (2) has a frequency range of 500 Hz to 5000 Hz and a power range of 500 W to 20 Kw. The output power is adjustable in ten levels, and a conical resonant cavity is used to achieve sound wave focusing.

6. The acoustically excited underground coal gasification combustion enhancement emission device according to claim 1, characterized in that: The inner wall of the acoustic wave transmission channel (4) is provided with a 2 mm thick metal-ceramic coating.

7. The acoustically excited underground coal gasification combustion enhancement emission device according to claim 1, characterized in that: The three-stage amplifier (5) adopts a horn-shaped structure with a slant angle range of 10°.

8. The acoustically excited underground coal gasification combustion enhancement emission device according to claim 1, characterized in that: The three-stage linkage adjustment bracket (6) adopts a combined transmission mechanical structure of central drive gear and graded driven gear for phase synchronization adjustment, with an initial launch angle of 10°.

9. The acoustically excited underground coal gasification combustion enhancement emission device as described in claim 1, characterized in that: The composite sensor (7) has 5 sets of independent precious metal armored thermocouples inside, with a temperature range of 0~1600℃. Its gas detection types include H2, CO, O2, CO2, and CH4, and the gas detection accuracy is ±1%FS.

10. A method for implementing a sound-wave-excited underground coal gasification combustion enhancement emission device as described in any one of claims 1-9, characterized in that: Includes the following steps: (1) The acoustically excited underground coal gasification combustion enhancement emission device is arranged in the gasification channel through the injection well; (2) The gasification reaction status is monitored in real time by a composite sensor (7). When the effective gas content in the syngas is less than 60% or the temperature in the gasification zone is less than 500℃, the acoustic emission device is activated. (3) By adjusting the frequency, power and emission angle of the sound waves, the ash layer on the surface of the coal body is removed, and the gasification reaction is enhanced; (4) If the reaction state still does not improve after adjustment, the gas injection position of the underground coal gasification combustion enhancement emission device based on acoustic excitation is adjusted to the preset position, and a second ignition operation is performed to start a new round of underground coal gasification process at the new position.

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