Combustion head assembly and coiled tubing

Abstract

The utility model relates to a combustion head assembly and a coiled tubing, the combustion head assembly comprises a combustion head, the combustion head is provided with a combustion-supporting channel used for conveying combustion-supporting gas, the combustion head is provided with an oxygen channel used for conveying oxygen, and the combustion head is provided with an electric ignition device; the protective cover comprises a cover body, the cover body is arranged at the end, provided with the electric ignition device, of the combustion head, the cover body is provided with a containing space used for containing the electric ignition device, and the cover body is provided with a first hole communicated with the containing space. The protective cover can prevent the electric ignition device of the combustion head from being damaged by the impact force of the sleeve, the first hole is formed in the cover body, it can be ensured that combustion-supporting gas is released to an underground gasification reaction area through the first hole, meanwhile, the gas can be prevented from being ignited in a sealed environment to cause explosion, and the safety of the combustion process is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underground coal gasification, and particularly relates to a combustion head assembly and a coiled tubing. BACKGROUND

[0002] At present, the underground coal gasification technology has been basically mature, but the process and equipment used for mining have not been industrialized. The underground coal gasification (UCG) is a process of controlled combustion of coal in situ, through pyrolysis of coal and a series of chemical reactions of coal with oxygen and water vapor to produce H2, CO and CH4 combustible gas. The UCG is also called "gasification coal mining" or "chemical coal mining". The underground gasification can fundamentally eliminate the underground operation danger of coal mining, output the energy contained in the coal seam to the ground in a clean way, and leave the residue and waste liquid underground, thereby greatly reducing the pollution caused by coal mining and gas production to the environment.

[0003] In the related art, the control of the retreat of the gas injection point underground gasification technology refers to setting a gas injection pipe in the gasification channel, and continuously or intermittently retreating the gas injection pipe to realize the continuous or intermittent retreat of the gas injection point. Before collecting the combustible gas, an ignitable sleeve is pre-buried in the coal underground gasification layer, the coiled tubing is passed through the sleeve, and then is lowered to the gasification reaction zone of the underground gasification layer at the well bottom. The end of the coiled tubing is provided with an ignition device, and the coal seam is ignited by the ignition device to realize the stable production of the combustible gas. Since the ignition device is in an exposed state, the nozzle of the ignition device is easy to hit the sleeve wall (or the well wall) during the lowering process, resulting in damage of the nozzle and failure of normal ignition. CONTENT OF THE UTILITY MODEL

[0004] The present application provides a combustion head assembly and a coiled tubing to solve the technical problem that the nozzle of the ignition device is easy to hit the sleeve wall during the lowering process of the existing coiled tubing due to the exposed state of the ignition device, resulting in damage of the nozzle and failure of normal ignition.

[0005] The present application provides a combustion head assembly, comprising: a combustion head, the combustion head is provided with a combustion-supporting channel for conveying combustion-supporting gas, the combustion head is provided with an oxygen channel for conveying oxygen, and one end of the combustion head is provided with an electric ignition device; a protective cover, the protective cover comprises a cover body, the cover body is arranged at the end of the combustion head provided with the electric ignition device, the cover body is provided with a containing space for accommodating the electric ignition device, and a first hole in communication with the containing space is arranged on the cover body.

[0006] In a possible implementation manner, the first hole is provided in plurality, and the cover body is provided in a hollow cylindrical shape, and the plurality of first holes are arranged in a circumferential direction of the cover body and / or arranged in an axial direction of the cover body.

[0007] In a possible implementation, the cover body is provided with a baffle plate at one end away from the combustion head, and the baffle plate is provided with a second hole in communication with the accommodating space.

[0008] In a possible implementation, the second hole is provided in plurality, and the plurality of second holes are arranged in a ring shape on the baffle plate.

[0009] In a possible implementation, the first end of the cover body is provided with an internal thread, and the combustion head is provided with an external thread matched with the internal thread.

[0010] In a possible implementation, the combustion head is made of a high-temperature-resistant alloy material, and the melting point of the protective cover is lower than the melting point of the combustion head.

[0011] In a possible implementation, the melting point of the protective cover is lower than 1000℃.

[0012] In a possible implementation, the protective cover is made of at least one of the following materials: copper alloy, aluminum alloy, polyformaldehyde, polytetrafluoroethylene, nylon. An alloy material or a non-metallic material is used.

[0013] In a possible implementation, the protective cover comprises a limiting piece, which is arranged on the cover body or the baffle plate, and is connected with the nozzle of the electric ignition device, for limiting the distance between the nozzle of the electric ignition device and the baffle plate.

[0014] In a possible implementation, the limiting piece comprises a supporting rod and a clamping ring, the supporting rod is arranged on the inner wall of the cover body, and the end of the supporting rod away from the cover body is arranged to extend along the radial direction of the cover body and is connected with the clamping ring, and the clamping ring is clamped with the nozzle of the electric ignition device.

[0015] Alternatively, the supporting rod is arranged on the inner wall of the baffle plate, and the end of the supporting rod away from the baffle plate is arranged to extend along the axial direction of the cover body and is connected with the clamping ring, and the clamping ring is clamped with the nozzle of the electric ignition device.

[0016] The present application provides a coiled tubing comprising the combustion head assembly as described above.

[0017] Compared with the prior art, the above technical solution provided by the embodiments of the present application has the following advantages:

[0018] The combustion head assembly and coiled tubing provided in this application embodiment prevent damage to the combustion head's electric ignition device from impact with the casing during the combustion head's installation in the well, especially when entering the horizontal section. A first hole on the cover ensures that the combustion-supporting gas and oxygen are released into the downhole gasification reaction zone. The electric ignition device ignites the combustion-supporting gas, and the resulting high temperature burns the protective cover. Without the first hole, the gas ignites in a sealed environment, posing an explosion risk. Changing the combustion process to an open environment improves safety. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0022] Figure 1 This is a schematic diagram of the structure of a combustion head assembly provided in one embodiment of this application;

[0023] Figure 2 for Figure 1 The front view of the burner head of the burner head assembly is shown.

[0024] Figure 3 for Figure 1 A perspective view of the protective cover of the burner head assembly is shown;

[0025] Figure 4 for Figure 3 The front view of the protective cover of the combustion head assembly is shown;

[0026] Figure 5 For along Figure 4 A cross-sectional view along the AA direction;

[0027] Figure 6 for Figure 3 The image shown is a bottom view of the burner head assembly.

[0028] Figure 7A structural schematic diagram of a combustion head assembly provided for another embodiment of the present application is shown in the figure.

[0029] Figure 8 A structural schematic diagram of a combustion head assembly provided for another embodiment of the present application is shown in the figure.

[0030] Figure 9 A structural schematic diagram of a coiled tubing provided for an embodiment of the present application is shown in the figure.

[0031] Explanation of reference numerals:

[0032] 100, combustion head assembly;

[0033] 1, protective cover; 11, cover body; 111, accommodating space; 112, internal thread; 113, first hole; 12, baffle; 121, second hole; 13, limiting member; 131, supporting rod; 132, snap ring;

[0034] 2, combustion head; 21, electric ignition device; 22, temperature measuring sensor; 23, external thread; 24, second nozzle;

[0035] 200, coiled tubing. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0037] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplifying the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, reference numerals and / or letters can be repeated in different examples in the present application. Such repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed.

[0038] For the convenience of description, spatial relative terms can be used in the specification to describe the relative position relationship or movement condition of one element or feature relative to another element or feature as shown in the drawings, such as "inner", "outer", "inboard", "outboard", "under", "below", "on", "above", "front", "back", and the like. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawings is turned over or the posture is changed or the movement state is changed, the directional indications will also change accordingly, for example: the element described as "under" or "below" another element or feature will be oriented as "above" or "above" another element or feature. Therefore, the example term "below" can include both the upper and lower positions. The device can be additionally oriented (rotated by 90 degrees or in other directions), and the spatial relative relationship descriptors used in the specification are interpreted accordingly.

[0039] In the related art, the control of the retreating gas injection point underground gasification technology refers to setting a gas injection pipe in the gasification channel, and realizing the continuous or intermittent retreat of the gas injection point by continuous or intermittent retreat of the gas injection pipe. Before collecting combustible gas, a flammable sleeve is pre-buried in the coal underground gasification layer, the coiled tubing is passed through the sleeve, and then is lowered to the gasification reaction zone of the underground gasification layer at the bottom of the well. The end of the coiled tubing is provided with an ignition device, and the coal layer is ignited by the ignition device to realize stable production of combustible gas. Since the ignition device is in an exposed state, the nozzle of the ignition device is easy to hit the sleeve wall during the lowering process, resulting in damage of the nozzle and failure of normal ignition.

[0040] In order to solve the technical problem that the nozzle of the ignition device is easy to hit the sleeve wall during the lowering process of the existing coiled tubing due to the exposed state of the ignition device, resulting in damage of the nozzle and failure of normal ignition, the present application provides a combustion head assembly and a coiled tubing, which can prevent the electric ignition device of the combustion head from being damaged by the impact force of the sleeve, and can also avoid explosion of gas ignited in a sealed environment, thereby improving the safety of the combustion process.

[0041] Figures 1 to 3 A combustion head assembly 100 is provided in the present application, which comprises a combustion head 2 and a protective cover 1. The combustion head 2 is provided with a combustion-supporting channel for conveying combustion-supporting gas. The combustion head 2 is provided with an oxygen channel for conveying oxygen. The combustion head 2 is provided with an electric ignition device 21. The protective cover 1 comprises a cover body 11, which is arranged at one end of the combustion head 2 provided with the electric ignition device 21. The cover body 11 is provided with a containing space 111 for accommodating the electric ignition device 21. The cover body 11 is provided with a first hole 113 in communication with the containing space 111.

[0042] Exemplarily, the combustion head 2 provided with the electric ignition device 21 at one end can also be provided with a first nozzle (not shown in the figure) to provide the axial water mist required for the coal gasification reaction. It should be noted that the electric ignition device 21 can adopt a spark plug in the prior art, and the electric ignition device 21 can ignite the combustion-supporting gas. Therefore, the combustion head 2 can deliver the combustion-supporting gas, oxygen and water to the gasification reaction zone. Alternatively, the combustion-supporting gas can include methane, propane and other gases to help ignite the coal and start the gasification process.

[0043] It should be noted that the end of the combustion head 2 provided with the electric ignition device 21 is first lowered into the well, and gradually approaches the gasification reaction zone. When reaching the gasification reaction zone, the electric ignition device 21 of the combustion head 2 can ignite the combustion-supporting gas, so that the coal in the gasification reaction zone can be combusted in situ, and through pyrolysis of the coal and a series of chemical reactions between the coal and oxygen and water vapor, combustible gases such as H2, CO and CH4 are generated.

[0044] It can be understood that, as shown in Figure 1 During the lowering of the combustion head 2 into the well, especially during the process of entering the horizontal section of the well, the protective cover 1 can prevent the electric ignition device 21 of the combustion head 2 from being damaged by the impact force of the casing. The first hole 113 provided on the cover body 11 can ensure that the combustion-supporting gas and oxygen are released to the gasification reaction zone in the well through the first hole 113, and the electric ignition device 21 ignites the combustion-supporting gas, and the gas combustion forms high temperature to burn the protective cover 1. If the first hole 113 is not provided, the gas is ignited in a sealed environment, which has the risk of explosion. Changing the combustion process to an open environment can improve the safety of the combustion process.

[0045] It should be noted that the first hole 113 can be provided with one or more. When one first hole 113 is provided, the first hole 113 can be provided in a circular arc shape, and the circular arc-shaped first hole 113 is arranged along the circumferential direction of the cover body 11; the first hole 113 can also be provided in a rectangular shape, and the rectangular first hole 113 is arranged along the axial direction of the cover body 11. In this way, the air flowability of the space inside and outside the cover body 11 can be increased as much as possible to avoid the gas from being ignited in a sealed environment and exploding. As shown in Figure 4 The first hole 113 can be provided with multiple first holes 113, and more first holes 113 can improve the gas permeability of the combustion-supporting gas to avoid the gas from being ignited in a sealed environment and exploding.

[0046] The working process of the embodiment is that first, the combustible sleeve is pre-buried in the underground coal gasification layer, then the combustion head 2 is passed through the sleeve, the combustion head 2 is lowered to the gasification reaction zone of the underground coal gasification layer at the well bottom, the combustion-supporting gas and oxygen are injected into the well bottom after passing through the first holes 113 of the protective cover 1, the electric ignition device 21 ignites the combustion-supporting gas, the gas combustion generates high temperature, and the protective cover 1 is burned; then, the combustion head 2 sprays axial water mist, so that the coal in the gasification reaction zone is combusted in situ to generate combustible gases such as H2, CO and CH4.

[0047] Optionally, as shown in Figure 2 , the peripheral side of the combustion head 2 can also be provided with a second nozzle 24, the second nozzle 24 can spray radial water mist, part of the radial water mist is sprayed to the wall surface of the sleeve, the well wall or the coal wall, which can cool the wall surface of the sleeve on the one hand, avoid the sleeve from being burned in advance due to high temperature environment and causing the coal seam to collapse in advance, and prevent the coal seam from backfire combustion on the other hand; the other part of the radial water mist is sprayed to the peripheral side of the combustion head 2, so as to cool the combustion head 2 and avoid the combustion head 2 from being burned and failed in high temperature working environment. Therefore, the sleeve and the combustion head 2 can work normally in the underground high temperature environment, and the working reliability of the sleeve and the combustion head 2 is improved.

[0048] In one embodiment, as shown in Figure 3 , the cover body 11 is provided in a hollow cylindrical shape, and the plurality of first holes 113 are arranged along the circumferential direction of the cover body 11; and / or, the plurality of first holes 113 are arranged along the axial direction of the cover body 11. It can be understood that the plurality of first holes 113 arranged along the circumferential direction of the cover body 11 can make the combustion-supporting gas released uniformly from the inside space of the cover body 11 to the underground gasification reaction zone along the circumferential direction of the cover body 11, and the plurality of first holes 113 arranged along the axial direction of the cover body 11 can make the combustion-supporting gas released uniformly from the inside space of the cover body 11 to the underground gasification reaction zone along the axial direction of the cover body 11, while also improving the combustion uniformity of the protective cover 1 and improving the burning rate.

[0049] In one embodiment, as shown in Figure 5 and Figure 6 , the end of the cover body 11 away from the combustion head 21 is provided with a baffle 12, and the baffle 12 is provided with a second hole 121 communicating with the accommodating space 111. It can be understood that the baffle 12 can prevent the electric ignition device 21 of the combustion head 21 from being damaged by the impact force of the sleeve during the process of lowering the combustion head 2 into the well, especially during the process of entering the horizontal section of the well. The second hole 121 provided on the baffle 12 can ensure that the combustion-supporting gas and oxygen are released to the underground gasification reaction zone after passing through the second hole 121, preventing the gas from igniting and exploding in a sealed environment.

[0050] Optionally, the baffle 12 and the cover 11 can be integrally formed, and the baffle 12 and the cover 11 can also be connected by means of a snap-fit ​​and slot structure, a threaded connection structure, etc.

[0051] It should be noted that there may be one or more second holes 121. When one second hole 121 is provided, the arc-shaped second hole 121 extends circumferentially along the baffle 12; the second hole 121 can also be rectangular, with the rectangular second hole 121 extending radially along the baffle 12. This arrangement maximizes airflow between the inside and outside of the enclosure 11, preventing gas from igniting in a sealed environment and causing an explosion. Figure 4 As shown, multiple second holes 121 can be provided. Providing more second holes 121 can increase the permeability of the combustion-supporting gas and prevent the gas from igniting and exploding in a sealed environment. In one embodiment, as shown... Figure 6 As shown, multiple second holes 121 are provided, and the multiple second holes 121 are arranged in a ring on the baffle 12. It can be understood that the multiple second holes 121 arranged in a ring on the baffle 12 allows the combustion-supporting gas to pass through the internal space of the cover 11 through the multiple second holes 121 and then be evenly released into the downhole gasification reaction zone.

[0052] Optionally, such as Figure 6 As shown, a temperature sensor 22 can be installed at the end of the burner head 21 near the gasification reaction zone. The temperature sensor 22 can be a thermocouple as used in existing technology. The temperature sensor 22 can detect the temperature of the environment where the combustion tube is located and adjust the position of the burner head 2 appropriately according to the temperature at the bottom of the well and the composition of the outlet gas, thereby achieving continuous backward gasification. The cover 11 is installed on the burner head 2, and the temperature sensor 22 is set in the accommodating space 111 of the cover 11, which can simultaneously protect the nozzle of the electric ignition device 21 and the temperature sensor 22 from damage caused by external impact.

[0053] In one embodiment, such as Figure 2 and Figure 3 As shown, the cover 11 is fitted onto the end of the burner head 2 where the electric ignition device 21 is located. The inner circumference of the cover 11 is provided with an internal thread 112, and the outer wall of the burner head 21 is provided with an external thread 23 that mates with the internal thread 112. By connecting the internal thread 112 of the cover 11 with the external thread 23 of the burner head 2, the cover 11 can be installed on the burner head 2, preventing the protective cover 1 from falling off due to external force and ensuring the protective effectiveness of the protective cover 1.

[0054] In one embodiment, the combustion head 2 is made of high-temperature alloy material, and the melting point of the protective cover 1 is lower than that of the combustion head 2. The combustion head 2 is made of high-temperature alloy to improve the high-temperature resistance of the combustion head 2 and ensure that the combustion head 2 can work normally in a high-temperature environment. The melting point of the protective cover 1 is lower than that of the combustion head 2, so that the protective cover 1 can be burned in a high-temperature environment.

[0055] Further, the melting point of the protective cover 1 is lower than 1000℃. Generally, the normal working temperature of the combustion head 2 is 1000℃-1400℃, therefore, the melting point of the protective cover 1 is lower than 1000℃. In this embodiment, first, an ignitable sleeve is embedded in the coal underground gasification layer, then the combustion head 2 is inserted into the sleeve and reaches the gasification reaction zone of the underground gasification layer at the bottom of the well, the combustion-supporting gas is injected into the bottom of the well through the through hole 13 of the protective cover 1, the electric ignition device 21 ignites the combustion-supporting gas, and the gas combustion generates high temperature, when the environmental temperature reaches 1000℃, the protective cover 1 is burned.

[0056] Further, the protective cover 1 is made of at least one of the following materials: copper alloy, aluminum alloy, polyformaldehyde, polytetrafluoroethylene, nylon. That is, the protective cover 1 can be made of alloy materials such as copper alloy and aluminum alloy, which can ensure the structural strength of the protective cover 1 and reduce the weight of the protective cover 1. The protective cover 1 can also be made of non-metallic materials with high hardness such as polyformaldehyde, polytetrafluoroethylene, and nylon to improve the structural strength of the protective cover 1 and ensure the protection effectiveness of the protective cover 1.

[0057] In some embodiments, as shown in Figure 7 The protective cover 1 includes a limiting piece 13, which is arranged on the cover body 11 or the baffle 12, and is connected with the nozzle of the electric ignition device 21 to limit the distance between the nozzle of the electric ignition device 21 and the baffle 12. It can be understood that the limiting piece 13 can limit the distance between the nozzle of the electric ignition device 21 and the baffle 12, thereby avoiding that the protective cover 1 touches the nozzle of the electric ignition device 21 during installation of the protective cover 1 and causes damage to the nozzle.

[0058] In one embodiment, as shown in Figure 7As shown, the limiting member 13 includes a supporting rod 131 and a clamping ring 132, the supporting rod 131 is arranged on the inner wall of the cover body 11, the end of the supporting rod 131 away from the cover body 11 is arranged along the radial direction of the cover body 11 and connected with the clamping ring 132, and the clamping ring 132 is clamped with the nozzle of the electric ignition device 21. Since the nozzle of the electric ignition device 21 is conical, during the installation of the protective cover 1, the clamping ring 132 is aligned with the nozzle of the electric ignition device 21, the cover body 11 is rotated to be screwed on the combustion head 2, and as the cover body 11 is screwed, the clamping ring 132 is gradually clamped with the nozzle of the electric ignition device 21, thereby limiting the distance between the nozzle of the electric ignition device 21 and the baffle 12, and the limiting function is realized.

[0059] In one embodiment, as Figure 8 shown, the limiting member 13 includes a supporting rod 131 and a clamping ring 132, the supporting rod 131 is arranged on the inner wall of the cover body 11, the end of the supporting rod 131 away from the cover body 11 is arranged along the radial direction of the cover body 11 and connected with the clamping ring 132, and the clamping ring 132 is clamped with the nozzle of the electric ignition device 21. Specifically, in order to avoid the interference between the supporting rod 131 and the nozzle of the electric ignition device 21, at least two inclined rods are arranged at the end of the supporting rod 131 close to the electric ignition device 21, the inclined rods are arranged inclinedly relative to the axial direction of the cover body 11, the first end of the inclined rod is connected with the supporting rod 131, and the second end of the inclined rod is connected with the clamping ring 132. Since the nozzle of the electric ignition device 21 is conical, during the installation of the protective cover 1, the clamping ring 132 is aligned with the nozzle of the electric ignition device 21, the cover body 11 is rotated to be screwed on the combustion head 2, and as the cover body 11 is screwed, the clamping ring 132 is gradually clamped with the nozzle of the electric ignition device 21, thereby limiting the distance between the nozzle of the electric ignition device 21 and the baffle 12, and the limiting function is realized.

[0060] As Figure 9 shown, the present application provides a coiled tubing 200, which includes the combustion head assembly 100 as described above. The coiled tubing 200 provided by the present application includes the combustion head assembly 100 described above, and thus naturally has the technical effects of the combustion head assembly 100 described above, which will not be described herein.

[0061] It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order

[0062] Although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first", "second", and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0063] The foregoing is merely illustrative of the principles of this application and various modifications can be made by those skilled in the art without departing from the spirit and scope of the application. The above embodiments are illustrative, and not restrictive, of the scope of the application.

Claims

1. A combustion head assembly, characterized by, The combustion head is provided with a combustion channel for conveying combustion-supporting gas, and is provided with an oxygen channel for conveying oxygen, and is provided with an electric ignition device; The protective cover comprises a cover body provided at one end of the combustion head where the electric ignition device is arranged, and is provided with a containing space for accommodating the electric ignition device, and is provided with a first hole in communication with the containing space. The cover body is provided in a hollow cylindrical shape, and the first hole is provided in a plurality of holes arranged along the circumferential direction of the cover body; and / or, the first hole is provided in a plurality of holes arranged along the axial direction of the cover body.

2. The combustion head assembly of claim 1, wherein, The end of the cover body away from the combustion head is provided with a baffle, and the baffle is provided with a second hole in communication with the containing space.

3. The combustion head assembly of claim 1, wherein, The second hole is provided in a plurality of holes arranged in a ring shape on the baffle.

4. The combustion head assembly of claim 3, wherein, The cover body is provided with an internal thread, and the combustion head is provided with an external thread matched with the internal thread.

5. The combustion head assembly of claim 1, wherein, The combustion head is made of a high-temperature-resistant alloy material, and the melting point of the protective cover is lower than the melting point of the combustion head.

6. The combustion head assembly of claim 1, wherein, The melting point of the protective cover is lower than 1000℃; and the protective cover is made of at least one of the following materials: copper alloy, aluminum alloy, polyformaldehyde, polytetrafluoroethylene, nylon.

7. The combustion head assembly of claim 6, wherein, The protective cover comprises a limiting piece arranged on the cover body or the baffle, and the limiting piece is connected with the nozzle of the electric ignition device for limiting the distance between the nozzle of the electric ignition device and the baffle.

8. The combustion head assembly of claim 3, wherein, The limiting piece comprises a supporting rod and a clamping ring, the supporting rod is arranged on the inner wall of the cover body, and the end of the supporting rod away from the cover body is arranged in the radial direction of the cover body and connected with the clamping ring, and the clamping ring is connected with the nozzle of the electric ignition device; 9. The combustion head assembly of claim 8, wherein, Alternatively, the supporting rod is arranged on the inner wall of the baffle, and the end of the supporting rod away from the baffle is arranged in the axial direction of the cover body and connected with the clamping ring, and the clamping ring is connected with the nozzle of the electric ignition device. The combustion head assembly comprises the combustion head according to any one of claims 1 to 9.

10. A coiled tubing, characterized by ​

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