Anti-clogging device for underground coal gasification wells

Abstract

This utility model discloses an anti-clogging device for underground coal gasification wells, comprising a negative pressure adsorption pipe, a negative pressure fan, and a cyclone separator. The negative pressure adsorption pipe extends radially along the well and has a first end and a second end. The first end is inserted into the side wall of the well and communicates with it, while the second end extends outward. The diameter of the negative pressure adsorption pipe gradually decreases from the first end to the second end. The negative pressure fan is located at the second end of the negative pressure adsorption pipe and generates negative pressure to draw low-speed airflow carrying impurities into the well for preliminary impurity separation, resulting in a gas-solid mixture. The inlet of the cyclone separator is connected to the outlet of the negative pressure fan and is used to separate impurities in the low-speed airflow to obtain a pure airflow. This device can cover the separation of impurities of all particle sizes, significantly reducing the accumulation of impurities in the well, preventing clogging, and greatly improving the operating efficiency and stability of the well.

Description

Technical Field

[0001] This utility model relates to the field of underground coal gasification technology, specifically to an anti-clogging device for underground coal gasification wells. Background Technology

[0002] In the underground coal gasification industry, the gas outlet well is an important gas emission channel. However, the gas flow discharged from the gas outlet well usually carries a large amount of impurities such as coal ash, tar, and dust. These impurities can easily accumulate in the gas outlet well, causing blockage and affecting the normal emission of gas and the continuity of production. Utility Model Content

[0003] The main purpose of this invention is to provide an anti-clogging device for underground coal gasification wells, which aims to solve the above-mentioned problems.

[0004] To achieve the above objectives, this utility model proposes an anti-clogging device for underground coal gasification wells, comprising: A negative pressure adsorption pipe extends radially along the gas outlet well and has a first end and a second end. The first end is inserted into the side wall of the gas outlet well and communicates with the gas outlet well. The second end extends outward. The diameter of the negative pressure adsorption pipe gradually decreases from the first end to the second end. A negative pressure fan, located at the second end of the negative pressure adsorption pipe, is used to generate negative pressure to draw the low-speed airflow carrying impurities from the outlet well into the negative pressure adsorption pipe for preliminary impurity separation, resulting in a gas-solid mixture; and, A cyclone separator, whose inlet is connected to the outlet of the negative pressure fan, is used to separate impurities in the low-speed airflow to obtain a pure airflow.

[0005] Optionally, the contraction angle of the negative pressure adsorption pipe is 30°.

[0006] Optionally, the diameter of the opening at the first end of the negative pressure adsorption pipe is set as D1, the diameter of the opening at the second end of the negative pressure adsorption pipe is set as D1, and the diameter of the gas outlet well is set as D, then D1=D / 2 and D1=D / 3.

[0007] Optionally, a transition pipe is provided between the negative pressure adsorption pipe and the negative pressure fan, and the inner wall of the transition pipe is coated with a hydrophobic polytetrafluoroethylene coating.

[0008] Optionally, the cyclone separator includes: The cyclone separator body includes an upper cylindrical part and a lower conical part arranged sequentially in the vertical direction. The upper cylindrical part has an air inlet on its side wall and an air outlet at its upper end. The air outlet is connected to the outlet of the negative pressure fan. The lower conical part has an ash discharge port at its lower end. An exhaust pipe is located at the air inlet at the upper part of the cylinder; An airlock valve is located at the air outlet at the lower part of the cone; and, A storage tank is located at the outlet of the airlock valve.

[0009] Optionally, the inner peripheral wall of the cyclone separator is provided with an alumina ceramic patch.

[0010] Optionally, the diameter of the upper part of the cylinder is greater than or equal to 500 mm and less than or equal to 1000 mm; The cone angle at the lower part of the cone is set to 45°.

[0011] Optionally, the diameter of the vent pipe is 1 / 3 of the diameter of the upper part of the cylinder.

[0012] Optionally, a reducing pipe is provided between the outlet of the negative pressure fan and the air inlet of the cyclone separator, and the diameter of the reducing pipe gradually increases from the end of the reducing pipe near the negative pressure fan to the end of the reducing pipe near the cyclone separator.

[0013] Optionally, the anti-clogging device for the underground coal gasification well further includes: A mounting base is provided on the side wall of the gas outlet well and located below the negative pressure adsorption pipe; and, A pressure transmitter is mounted on the mounting base via a flange and is used to monitor the pressure in the gas outlet well. The pressure transmitter is electrically connected to the negative pressure fan so that the negative pressure fan adjusts its speed according to the monitoring results of the pressure transmitter.

[0014] In the technical solution of this utility model, when the coal gas containing impurities produced by underground coal gasification flows in the gas outlet well, the negative pressure fan operates in the negative pressure adsorption pipe to create a negative pressure environment. Attracted by the negative pressure, the low-speed airflow (i.e., airflow with a relatively low velocity) in the gas outlet well carries impurities (such as impurities with a particle size ≥ 50 μm) and preferentially enters the negative pressure adsorption pipe. Since the negative pressure adsorption pipe is tapered, the low-speed airflow accelerates at the second end, and inertia allows for the initial separation of some impurities, resulting in a preliminarily purified gas-solid mixture. This gas-solid mixture flows through the negative pressure fan into the cyclone separator, while the gas outlet... The main airflow with a relatively high velocity inside the well continues to be discharged normally along the central channel of the outlet well, thereby achieving uninterrupted separation of airflows with different velocities and ensuring stable operation of downstream equipment. After the gas-solid mixture enters the cyclone separator at a certain speed, a rotating airflow is formed inside the cyclone separator. Under the action of centrifugal force, impurities in the gas-solid mixture spiral downward along the inner wall of the cyclone separator, thereby obtaining a pure airflow. In this way, compared with a single filtration method, it can cover the separation of impurities of all particle sizes, significantly reduce the accumulation of impurities in the outlet well, prevent blockage, and greatly improve the operating efficiency and stability of the outlet well. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 A schematic diagram of an embodiment of the anti-clogging device for underground coal gasification wells provided by this utility model.

[0017] Explanation of icon numbers:

[0018] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0021] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0022] In the underground coal gasification process, the gas outlet well is a crucial gas emission channel. However, the gas stream discharged from the well typically carries a large amount of impurities such as coal ash, tar, and dust. These impurities easily accumulate within the well, causing blockages and consequently affecting normal gas emission and production continuity. Traditional methods for treating impurities in gas outlet wells, such as simple filtration using a single filter screen, are ineffective at removing fine particulate impurities of 2-10 μm.

[0023] In view of this, the present invention provides an anti-clogging device 100 for underground coal gasification wells. Figure 1 An embodiment of the anti-clogging device 100 for underground coal gasification wells provided by this utility model.

[0024] Please see Figure 1The coal underground gasification well anti-clogging device 100 includes a negative pressure adsorption pipe 1, a negative pressure fan 2, and a cyclone separator 3. The negative pressure adsorption pipe 1 extends radially along the well 200 and has a first end and a second end. The first end is inserted into the side wall of the well 200 and communicates with the well 200. The second end extends outward. The diameter of the negative pressure adsorption pipe 1 gradually decreases from the first end to the second end. The negative pressure fan 2 is located at the second end of the negative pressure adsorption pipe 1 and is used to generate negative pressure to draw the low-speed airflow carrying impurities in the well 200 into the negative pressure adsorption pipe 1 for preliminary impurity separation to obtain a gas-solid mixed flow. The inlet of the cyclone separator 3 is connected to the outlet of the negative pressure fan 2 and is used to separate impurities in the low-speed airflow to obtain a pure airflow.

[0025] In this utility model's technical solution, when the coal gas containing impurities produced by underground coal gasification flows within the gas outlet well 200, the negative pressure fan 2 operates within the negative pressure adsorption pipe 1 to create a negative pressure environment. Attracted by the negative pressure, the low-speed airflow (i.e., airflow with a relatively low velocity) within the gas outlet well 200 carries impurities (such as impurities with a particle size ≥ 50 μm) and preferentially enters the negative pressure adsorption pipe 1. Since the negative pressure adsorption pipe 1 is tapered, the low-speed airflow accelerates at the second end, and inertia allows for the initial separation of some impurities, resulting in a preliminarily purified gas-solid mixture. This gas-solid mixture flows through the negative pressure fan 2 into the cyclone separator 3, while the gas outlet well 200... The main airflow with a relatively high velocity within the outlet well 200 continues to be discharged normally along the central channel of the outlet well 200, thereby achieving uninterrupted separation of airflows with different velocities and ensuring stable operation of downstream equipment. After the gas-solid mixture enters the cyclone separator 3 at a certain speed, a rotating airflow is formed within the cyclone separator 3. Under the action of centrifugal force, impurities in the gas-solid mixture undergo a spiral descent along the inner wall of the cyclone separator 3, thereby obtaining a pure airflow. In this way, compared with a single filtration method, it can cover the separation of impurities of all particle sizes, significantly reduce the accumulation of impurities within the outlet well 200, prevent blockage, and greatly improve the operating efficiency and stability of the outlet well 200.

[0026] Furthermore, in one embodiment of this utility model, the contraction angle of the negative pressure adsorption pipe 1 is 30°, which is beneficial to accelerating the low-speed airflow.

[0027] Specifically, in one embodiment of this utility model, the diameter of the opening at the first end of the negative pressure adsorption pipe 1 is set as D1, the diameter of the opening at the second end of the negative pressure adsorption pipe 1 is set as D2, and the diameter of the gas outlet well is set as D, then D1=D / 2 and D2=D / 3.

[0028] Specifically, the negative pressure adsorption pipe 1 is welded smoothly to the gas outlet well 200, which helps to accelerate the low-speed airflow.

[0029] It should be noted that the angle between the axis of the negative pressure adsorption pipe 1 and the axis of the gas outlet well 200 is 90±1°. During the welding process, tools such as a level are used for calibration to lay the foundation for subsequent stable operation.

[0030] For details, please refer to Figure 1 A transition pipe 4 is provided between the negative pressure adsorption pipe 1 and the negative pressure fan 2. The inner wall of the transition pipe 4 is coated with a hydrophobic polytetrafluoroethylene coating. In this way, the negative pressure adsorption pipe 1 and the negative pressure fan 2 are connected through the transition pipe 4, and the problem of dual corrosion from high-temperature tar and abrasion during coal gasification is solved by setting a hydrophobic polytetrafluoroethylene coating on the inner wall.

[0031] Furthermore, the transition pipe 4 is made of 316L stainless steel with a wall thickness of 8mm, and the polytetrafluoroethylene (PTFE) hydrophobic coating is 50μm thick with a surface roughness Ra≤0.8μm.

[0032] Specifically, the transition pipe 4 is connected to the negative pressure adsorption pipe 1 and the negative pressure fan 2 via a flange.

[0033] Specifically, in order to reduce the vibration impact during the operation of the negative pressure fan 2, the base of the negative pressure fan 2 can be leveled using vibration damping pads.

[0034] For details, please refer to Figure 1 The cyclone separator 3 includes a cyclone separator body 31, an air outlet pipe 32, an airlock valve 33, and a storage tank 34. The cyclone separator body 31 includes an upper cylindrical part 311 and a lower conical part 312 arranged sequentially in the vertical direction. The upper cylindrical part 311 has an air inlet on its side wall and an air outlet at its upper end. The air outlet is connected to the outlet of the negative pressure fan 2. The lower conical part 312 has an ash discharge port at its lower end. The air outlet pipe 32 is located at the air inlet of the upper cylindrical part 311. The airlock valve 33 is located at the air outlet of the lower conical part 312. The storage tank 34 is located at the outlet of the airlock valve 33. Thus, the gas-solid mixture flowing into the cyclone separator 3 via the negative pressure fan 2 forms a rotating airflow within the cyclone separator body 31. Under the action of centrifugal force, impurities in the gas-solid mixture spiral down along the inner wall of the cyclone separator body 31 and are finally collected in the storage tank 34 through the ash discharge port. The purified airflow after cyclone separation is discharged through the air outlet pipe 32 and merges into the main gas pipeline for subsequent utilization.

[0035] Furthermore, the inner peripheral wall of the cyclone separator body 31 is provided with alumina ceramic patches to solve the problem of dual corrosion from high-temperature tar and abrasion during coal gasification.

[0036] Specifically, the diameter of the upper part 311 of the cylinder is greater than or equal to 500 mm and less than or equal to 1000 mm; the cone angle of the lower part 312 of the cone is set to 45°.

[0037] Specifically, the diameter of the vent pipe 32 is one-third of the diameter of the upper part 311 of the cylinder. More specifically, the lower end of the vent pipe 32 may extend into the upper part 311 of the cylinder.

[0038] Specifically, in one embodiment of this utility model, the airlock valve 33 is a flap valve.

[0039] For details, please refer to Figure 1 A reducing pipe 5 is provided between the outlet of the negative pressure fan 2 and the air inlet of the cyclone separator 31, and the diameter of the reducing pipe 5 gradually increases from the end of the reducing pipe 5 near the negative pressure fan 2 to the end of the reducing pipe 5 near the cyclone separator 31.

[0040] Thus, by setting the variable diameter pipe 5, the airflow velocity can be reduced, and equipment vibration can be decreased. Simultaneously, since the airflow after passing through the negative pressure fan 2 is mainly turbulent with high dynamic pressure, the variable diameter pipe 5 can gradually expand to convert the dynamic pressure into static pressure. The converted static pressure can help overcome the resistance in subsequent channels, improving capacity utilization efficiency. It should be noted that, according to relevant literature, the variable diameter pipe 5 is a diffuser, and its divergence angle should generally not be too large (usually ≤15°), otherwise it may lead to boundary layer separation of the airflow, forming vortices, which would increase local resistance. Specifically, in one embodiment of this invention, the variable diameter pipe 5 is set with a divergence angle of 15°.

[0041] Furthermore, the variable diameter pipe 5 is welded to the negative pressure fan 2 and the cyclone separator body 31. More specifically, symmetrical welding is used to prevent the cyclone separator body 31 from deforming due to welding stress, which would affect the separation effect.

[0042] For details, please refer to Figure 1 The coal underground gasification gas well anti-clogging device 100 also includes a mounting base and a pressure transmitter 6. The mounting base is used to be installed on the side wall of the gas well 200 and located below the negative pressure adsorption pipe 1. The pressure transmitter 6 is installed on the mounting base through a flange and is used to monitor the pressure in the gas well 200. The pressure transmitter 6 is electrically connected to the negative pressure fan 2 so that the negative pressure fan 2 adjusts its speed according to the monitoring result of the pressure transmitter 6.

[0043] Thus, compared to the impurity treatment method of the gas well 200 using pulse jet (which has high energy consumption, relies on manual intervention, and cannot adapt to complex and changing working conditions), this utility model, by setting the pressure transmitter 6, can monitor the pressure inside the well in real time, so that the negative pressure fan 2 can automatically adjust its speed according to the pressure changes inside the well, effectively reducing manual intervention. Specifically, when the monitored pressure inside the well increases (indicating increased impurities and greater airflow resistance), the fan speed is increased to enhance the adsorption force and ensure effective adsorption and separation of impurities; when the monitored pressure inside the well is stable, the speed can be appropriately reduced to achieve energy-saving operation.

[0044] It should be noted that the pressure transmitter 6 and the negative pressure fan 2 can be electrically connected wirelessly or via wired means, both of which are existing technologies. Furthermore, the setting for the negative pressure fan 2 to automatically adjust its speed according to changes in the well pressure is also existing technology, and will not be elaborated further here.

[0045] In addition, the pressure transmitter 6 is mounted on the side wall of the gas outlet well 200 via the mounting base, which can prevent the pressure sensing device from directly contacting the high-temperature gas flow inside the well.

[0046] It should be noted that, in order to visually inspect the flow field distribution of the system, tracer smoke can be released at the air inlet of the cyclone separator 3, and the flow field can be observed with the help of endoscopes and other equipment to ensure that there are no obvious dead air zones and to ensure the uniformity and efficiency of impurity separation.

[0047] Furthermore, the flange connection sealing surface between the pressure transmitter 6 and the mounting base is an RF convex surface, the gasket is an HG / T 20610 metal spiral wound gasket, and the bolt torque conforms to the SH / T 3406 standard.

[0048] Specifically, in one embodiment of this utility model, the mounting base is made of stainless steel.

[0049] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A device for preventing blockage in underground coal gasification wells, characterized in that, The anti-clogging device for the underground coal gasification well includes: A negative pressure adsorption pipe extends radially along the gas outlet well and has a first end and a second end. The first end is inserted into the side wall of the gas outlet well and communicates with the gas outlet well. The second end extends outward. The diameter of the negative pressure adsorption pipe gradually decreases from the first end to the second end. A negative pressure fan, located at the second end of the negative pressure adsorption pipe, is used to generate negative pressure to draw the low-speed airflow carrying impurities from the outlet well into the negative pressure adsorption pipe for preliminary impurity separation, resulting in a gas-solid mixture; and, A cyclone separator, whose inlet is connected to the outlet of the negative pressure fan, is used to separate impurities in the low-speed airflow to obtain a pure airflow.

2. The anti-clogging device for underground coal gasification wells as described in claim 1, characterized in that, The contraction angle of the negative pressure adsorption pipe is 30°.

3. The anti-clogging device for underground coal gasification wells as described in claim 1 or 2, characterized in that, The diameter of the first end of the negative pressure adsorption pipe is set as D1, the diameter of the second end of the negative pressure adsorption pipe is set as D2, and the diameter of the gas outlet well is set as D. Then D1 = D / 2 and D2 = D / 3.

4. The anti-clogging device for underground coal gasification wells as described in claim 1, characterized in that, A transition pipe is provided between the negative pressure adsorption pipe and the negative pressure fan, and the inner wall of the transition pipe is coated with a hydrophobic polytetrafluoroethylene coating.

5. The anti-clogging device for underground coal gasification wells as described in claim 1, characterized in that, The cyclone separator includes: The cyclone separator body includes an upper cylindrical part and a lower conical part arranged sequentially in the vertical direction. The upper cylindrical part has an air inlet on its side wall and an air outlet at its upper end. The air outlet is connected to the outlet of the negative pressure fan. The lower conical part has an ash discharge port at its lower end. An exhaust pipe is located at the air inlet at the upper part of the cylinder; An airlock valve is located at the air outlet at the lower part of the cone; and, A storage tank is located at the outlet of the airlock valve.

6. The anti-clogging device for underground coal gasification wells as described in claim 5, characterized in that, The inner peripheral wall of the cyclone separator is provided with alumina ceramic patches.

7. The anti-clogging device for underground coal gasification wells as described in claim 5, characterized in that, The diameter of the upper part of the cylinder is greater than or equal to 500 mm and less than or equal to 1000 mm; The cone angle at the lower part of the cone is set to 45°.

8. The anti-clogging device for underground coal gasification wells as described in claim 5, characterized in that, The diameter of the vent pipe is 1 / 3 of the diameter of the upper part of the cylinder.

9. The anti-clogging device for underground coal gasification wells as described in claim 5, characterized in that, A reducing pipe is provided between the outlet of the negative pressure fan and the air inlet of the cyclone separator body, and the diameter of the reducing pipe gradually increases from the end of the reducing pipe near the negative pressure fan to the end of the reducing pipe near the cyclone separator body.

10. The anti-clogging device for underground coal gasification wells as described in claim 1, characterized in that, The anti-clogging device for underground coal gasification wells also includes: A mounting base is provided on the side wall of the gas outlet well and located below the negative pressure adsorption pipe; and, A pressure transmitter is mounted on the mounting base via a flange and is used to monitor the pressure in the gas outlet well. The pressure transmitter is electrically connected to the negative pressure fan so that the negative pressure fan adjusts its speed according to the monitoring results of the pressure transmitter.

Images