Natural gas ignition device for starting stage of coal-fired unit

Abstract

The invention belongs to the field of coal-fired units, and particularly relates to a natural gas ignition device for the starting stage of a coal-fired unit, which comprises a natural gas pipeline system, a gas atmosphere gun burner, a micro-gas ignition pulverized coal burner and an air distribution system, the natural gas pipeline system is used for conveying natural gas to the gas atmosphere gun burner and the micro-gas ignition pulverized coal burner, and the air distribution system is used for conveying air to the gas atmosphere gun burner and the micro-gas ignition pulverized coal burner; the gas atmosphere gun combustor ignites the coal-fired unit through natural gas and air combustion, and meanwhile the micro-gas ignition pulverized coal combustor ignites the coal-fired unit through natural gas and air combustion. Natural gas is provided for the gas atmosphere gun combustor and the micro-gas ignition pulverized coal combustor through the natural gas pipeline system, the gas atmosphere gun combustor and the micro-gas ignition pulverized coal combustor are ignited through natural gas combustion, and the device has the advantages of being good in burnout characteristic and small in environmental pollution.

Description

Technical Field

[0001] The invention belongs to the field of coal-fired units, and in particular relates to a natural gas ignition device used in the startup phase of a coal-fired unit. Background Art

[0002] At present, coal-fired units consume a large amount of fuel during the cold start-up process or low-load operation, which means that the fuel ignition method consumes a lot of fuel and the consumption of auxiliary fuel is even greater. With the increasingly tight energy supply and rising oil prices, the startup cost of coal-fired units is also increasing.

[0003] In addition to the high cost of fuel ignition, coal-fired units also have the following problems:

[0004] (1) Poor burnout characteristics. Whether it is a light diesel ignition device or a heavy residual oil ignition device, the furnace torch is dark red during cold ignition, and black smoke billows in the furnace;

[0005] (2) Due to the incomplete combustion of fuel oil, if the electrostatic precipitator is put into operation, the incompletely burned oil mist will adhere to the electrostatic precipitator plate with the flue gas, which will have a great impact on the life and dust removal effect of the electrostatic precipitator. If the electrostatic precipitator equipment is not put into operation, black smoke will be emitted from the chimney, and the particulate matter emission will not meet the standard, causing pollution to the environment.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] In order to solve the technical problems existing in the prior art, the present invention provides a natural gas ignition device for the startup stage of a coal-fired unit. The present invention provides natural gas to a gas-fired atmospheric gun burner and a micro-gas ignition pulverized coal burner through a natural gas pipeline system. The gas-fired atmospheric gun burner and the micro-gas ignition pulverized coal burner are ignited by natural gas combustion, and have the advantages of good burnout characteristics and low environmental pollution.

[0008] The present invention includes the following technical solutions:

[0009] The present invention provides a natural gas ignition device for the startup stage of a coal-fired unit, comprising a natural gas pipeline system, a gas-fired atmospheric gun burner, a micro-gas ignition pulverized coal burner and an air distribution system, wherein the natural gas pipeline system is used to transport natural gas to the gas-fired atmospheric gun burner and the micro-gas ignition pulverized coal burner, and the air distribution system is used to transport air to the gas-fired atmospheric gun burner and the micro-gas ignition pulverized coal burner; the gas-fired atmospheric gun burner utilizes natural gas and air combustion to ignite the coal-fired unit, and the micro-gas ignition pulverized coal burner utilizes natural gas and air combustion to ignite the coal-fired unit.

[0010] Furthermore, the gas atmosphere gun burner includes a first high-energy ignition structure, an ignition air gun nozzle, a gas atmosphere gun main air gun and an air supply nozzle. The first high-energy ignition structure ignites the natural gas entering from the ignition air gun nozzle through a high-voltage electric spark. The natural gas ignites and ignites the natural gas entering from the gas atmosphere gun main air gun to achieve three-stage ignition. The air supply nozzle provides air for the three-stage ignition.

[0011] Furthermore, the micro-gas ignition pulverized coal burner includes a second high-energy ignition structure, a micro-gas gun air nozzle and a micro-gas gun nozzle. The second high-energy ignition structure ignites the natural gas entering the micro-gas gun nozzle through a high-voltage electric spark to achieve ignition; the micro-gas gun air nozzle provides air for ignition.

[0012] Furthermore, the natural gas pipeline system includes a first gas delivery section, a second gas delivery section and a third gas delivery section, one end of the first gas delivery section is connected to the natural gas supply structure, and the other end is respectively connected to one end of the second gas delivery section and the third gas delivery section, the other end of the second gas delivery section is connected to the gas atmosphere gun burner, and the other end of the third gas delivery section is connected to the micro-gas ignition pulverized coal burner.

[0013] Furthermore, a gas filter is provided on the first gas delivery section.

[0014] Furthermore, the second gas delivery section includes a first pipeline, a second pipeline and a third pipeline, one end of the first pipeline is connected to the first gas delivery section, and the other end is connected to one end of the second pipeline and the third pipeline respectively, and the other ends of the second pipeline and the third pipeline are respectively connected to the ignition air gun nozzle of the gas atmosphere gun burner and the main air gun of the gas atmosphere gun.

[0015] Furthermore, from the end away from the gas air gun burner to the end close to the gas air gun burner, a manual stop valve, a pneumatic ball valve and a flame arrester are sequentially arranged on the second pipeline, and / or a manual stop valve, a pneumatic ball valve and a flame arrester are sequentially arranged on the third pipeline;

[0016] And / or a manual stop valve, a pneumatic ball valve and a flame arrester are sequentially arranged on the third gas delivery section from an end away from the micro-gas ignition pulverized coal burner to an end close to the micro-gas ignition pulverized coal burner.

[0017] Furthermore, one end of the first gas transmission section close to the natural gas supply structure is connected to an exhaust pipeline; and one end of the first gas transmission section away from the natural gas supply structure is connected to a nitrogen filling pipeline.

[0018] Furthermore, a manual stop valve is provided on the nitrogen filling pipeline.

[0019] Furthermore, the air distribution system includes a main pipeline and a first sub-pipeline and a second sub-pipeline. One end of the main pipeline is used to let in air, and the other end is respectively connected to the first sub-pipeline and the second sub-pipeline. The first sub-pipeline is connected to the air distribution nozzle of the gas-fired atmospheric gun burner, and the second sub-pipeline is connected to the micro-gas gun air distribution nozzle of the micro-gas ignition pulverized coal burner.

[0020] By adopting the above technical solution, the present invention has the following advantages:

[0021] 1. The present invention provides natural gas to the gas-fired atmospheric gun burner and the micro-gas ignition pulverized coal burner through a natural gas pipeline system. The gas-fired atmospheric gun burner and the micro-gas ignition pulverized coal burner are ignited by natural gas combustion, and have the advantages of good burnout characteristics and low environmental pollution.

[0022] 2. The present invention uses natural gas to replace fuel oil, realizing oil-free ignition in the startup phase of coal-fired power station boilers. The fuel cost in the startup phase can be reduced by 60%, with obvious economic benefits. The natural gas burns completely, reducing pollutant emissions in the startup phase, and has no impact on the boiler body and subsequent environmental protection equipment.

[0023] 3. The system of the present invention is simple, safe, reliable and requires little modification.

[0024] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is a schematic structural diagram of a natural gas ignition device used in the startup phase of a coal-fired unit in an embodiment of the present invention;

[0027] Figure 2 It is a structural schematic diagram of a gas atmosphere gun burner in an embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the structure of a micro-gas ignition pulverized coal burner in an embodiment of the present invention;

[0029] Figure 4 The structure of the natural gas pipeline system in the embodiment of the present invention is shown in FIG. Figure 1 ;

[0030] Figure 5 The structure of the natural gas pipeline system in the embodiment of the present invention is shown in FIG. Figure 2 ;

[0031] Figure 6 It is a structural schematic diagram of the air distribution system in an embodiment of the present invention;

[0032] In the figure, 20-natural gas pipeline system, 21-first gas delivery section, 22-second gas delivery section, 221-first pipeline, 222-second pipeline, 223-third pipeline, 23-third gas delivery section, 30-gas air gun burner, 31-first high energy ignition structure, 32-ignition air gun nozzle, 33-gas air gun main air gun, 34-first ultraviolet flame detection structure, 35-air distribution nozzle, 40-micro gas ignition pulverized coal burner, 41-second high energy point Fire structure, 42-micro air gun air nozzle, 43-micro air gun nozzle, 44-second ultraviolet fire detection structure, 50-air distribution system, 51-main pipeline, 52-first auxiliary pipeline, 53-second auxiliary pipeline, 60-exhaust pipeline, 70-nitrogen filling pipeline, 1-gas filter, 2-manual stop valve, 3-pneumatic ball valve, 4-flame arrester, 5-manual butterfly valve, 6-pneumatic butterfly valve, 7-pressure transmitter, 8-pneumatic regulating valve, 9-safety valve, 10-pneumatic quick closing valve. DETAILED DESCRIPTION

[0033] The following description provides many different embodiments or examples for implementing different features of the present invention. The components and arrangements described in the following specific examples are only used to simplify the present invention and are only used as examples, not to limit the present invention.

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] This embodiment provides a natural gas ignition device for use in the startup phase of a coal-fired unit, such as Figure 1As shown, it includes a natural gas pipeline system 20, a gas-fired atmospheric gun burner 30, a micro-gas ignition pulverized coal burner 40 and an air distribution system 50, wherein the natural gas pipeline system 20 is used to transport natural gas to the gas-fired atmospheric gun burner 30 and the micro-gas ignition pulverized coal burner 40, and the air distribution system 50 is used to transport air to the gas-fired atmospheric gun burner 30 and the micro-gas ignition pulverized coal burner 40; the gas-fired atmospheric gun burner 30 utilizes natural gas and air combustion to ignite the coal-fired unit, and at the same time, the micro-gas ignition pulverized coal burner 40 utilizes natural gas and air combustion to ignite the coal-fired unit.

[0036] Furthermore, if Figure 2 As shown, the gas atmosphere gun burner 30 includes a first high-energy ignition structure 31, an ignition air gun nozzle 32, a gas atmosphere gun main air gun 33 and an air distribution nozzle 35. The first high-energy ignition structure 31 ignites the natural gas entering from the ignition air gun nozzle 32 through a high-voltage electric spark, and the natural gas ignites the natural gas entering from the gas atmosphere gun main air gun 33 to achieve three-stage ignition; the air distribution nozzle 35 provides air for the three-stage ignition.

[0037] Furthermore, if Figure 2 As shown, the gas atmosphere gun burner 30 also includes a first ultraviolet flame detection structure 34, which is used to detect the intensity signal of the flame of the three-stage ignition, and the opening of the pneumatic butterfly valve 6 at the air distribution nozzle 35 is controlled according to the flame intensity signal to adjust the ignition of the three-stage ignition flame.

[0038] It should be noted that the pneumatic butterfly valve 6 can be controlled manually or automatically by a controller. Specifically, the pneumatic butterfly valve 6 can be the pneumatic butterfly valve 6 on the first secondary pipe 52 of the air distribution system 50 described below.

[0039] Furthermore, if Figure 3 As shown, the micro-gas ignition pulverized coal burner 40 includes a second high-energy ignition structure 41, a micro-gas gun nozzle 43 and a micro-gas gun air supply nozzle 42. The second high-energy ignition structure 41 ignites the natural gas entering the micro-gas gun nozzle 43 through a high-voltage electric spark to achieve ignition; the micro-gas gun air supply nozzle 42 provides air for ignition.

[0040] The micro-gas ignition pulverized coal burner 40 further includes a second ultraviolet flame detection structure 44, and the second ultraviolet flame detection structure 44 is used to detect the intensity signal of the ignition flame.

[0041] The designed output of the micro-air gun nozzle 43 in the micro-air ignition pulverized coal burner 40 is 50-150 Nm3 / h, and the ignition fuel cost of the micro-air ignition pulverized coal burner 40 is about 40%-50% of the micro-oil ignition fuel cost, with obvious economic benefits.

[0042] It should be noted that the micro-gas ignition pulverized coal burner 40 and the micro-gas ignition pulverized coal burner 40 can be automatically controlled by an ignition control cabinet, that is, the micro-gas ignition pulverized coal burner 40 and the micro-gas ignition pulverized coal burner 40 are both connected to the DCS (distributed control system) of the ignition control cabinet, which can realize local / remote ignition control.

[0043] Furthermore, if Figure 4 As shown, the natural gas pipeline system 20 includes a first gas delivery section 21, a second gas delivery section 22 and a third gas delivery section 23, one end of the first gas delivery section 21 is connected to the natural gas supply structure, and the other end is respectively connected to one end of the second gas delivery section 22 and the third gas delivery section 23, the other end of the second gas delivery section 22 is connected to the gas atmosphere gun burner 30, and the other end of the third gas delivery section 23 is connected to the micro-gas ignition pulverized coal burner 40.

[0044] Preferably, the second gas delivery section 22 is connected to the gas air gun burner 30 through a dedicated metal hose, and the third gas delivery section 23 is connected to the micro-gas ignition pulverized coal burner 40 through a dedicated metal hose.

[0045] Furthermore, if Figure 4 As shown, the second gas delivery section 22 includes a first pipeline 221, a second pipeline 222 and a third pipeline 223. One end of the first pipeline 221 is connected to the first gas delivery section 21, and the other end is connected to one end of the second pipeline 222 and the third pipeline 223 respectively. The other ends of the second pipeline 222 and the third pipeline 223 are respectively connected to the ignition air gun nozzle 32 of the gas atmospheric gun burner 30 and the main air gun 33 of the gas atmospheric gun.

[0046] Furthermore, if Figure 4 As shown, from the end away from the gas air gun burner 30 to the end close to the gas air gun burner 30, the second pipeline 222 is sequentially provided with a manual stop valve 2, a pneumatic ball valve 3 and a flame arrester 4, and / or the third pipeline 223 is sequentially provided with a manual stop valve 2, a pneumatic ball valve 3 and a flame arrester 4. Such a setting makes it easier to control the content of the natural gas introduced, which is beneficial for ignition and can also improve safety.

[0047] Furthermore, a manual stop valve 2, a pneumatic ball valve 3 and a flame arrester 4 are sequentially arranged on the second gas delivery section 22 from the end away from the micro-gas ignition pulverized coal burner 40 to the end close to the micro-gas ignition pulverized coal burner 40. Such an arrangement makes it easier to control the content of the natural gas introduced, which is beneficial to ignition and can also improve safety.

[0048] Furthermore, if Figure 4As shown, a gas filter 1 is provided on the first gas delivery section 21 .

[0049] Furthermore, if Figure 5 As shown, the first gas delivery section 21 is provided with a gas filter 1, a manual stop valve 2, a pneumatic fast closing valve 10, a pneumatic regulating valve 8 and a pressure transmitter 7 in sequence from the input end to the output end; manual stop valves 2 are also provided on both sides of the pneumatic regulating valve 8 on the first gas delivery section 21; on both sides of the two manual stop valves 2, the first gas delivery section 21 is connected with a pipeline, that is, the two ends of the pipeline are respectively connected to the two sides of the two manual stop valves 2, and the pipeline is also provided with a manual stop valve 2.

[0050] After natural gas is burned and ignited, there will be gas residue in the gas pipeline. In order to avoid affecting the combustion and ignition, the gas pipeline needs to be purged and cleaned. Figure 5 As shown, one end of the first gas transmission section 21 close to the natural gas supply structure is connected to an exhaust pipe 60; the end of the first gas transmission section 21 away from the natural gas supply structure is connected to a nitrogen charging pipe 70. The pipeline is purged by charging nitrogen and then discharged through the exhaust pipe 60.

[0051] like Figure 5 As shown, further, a manual stop valve 2 is provided on the nitrogen filling pipeline 70.

[0052] like Figure 5 As shown, the exhaust pipeline 60 includes a first exhaust pipeline 60, a second exhaust pipeline 60 and a third exhaust pipeline 60, the input end of the first exhaust pipeline 60 is connected to the output ends of the second exhaust pipeline 60 and the third exhaust pipeline 60 respectively; the input end of the second exhaust pipeline 60 is connected to the first gas delivery section 21, and the connection point between the second exhaust pipeline 60 and the first gas delivery section 21 is located behind the pressure transmitter 7 on the first gas delivery section 21 (that is, the pressure transmitter 7 is closer to the input end of the first gas delivery section 21); the input end of the third exhaust pipeline 60 is connected to the first gas delivery section 21, and the connection point between the input end of the third exhaust pipeline 60 and the first gas delivery section 21 is located between the gas filter 1 and the first manual stop valve 2 on the first gas delivery section 21.

[0053] like Figure 5 As shown, from the input end to the output end of the second exhaust pipe 60 , a manual stop valve 2 and a manual ball valve are sequentially arranged on the second exhaust pipe 60 ; and a safety valve 9 is arranged on the third exhaust pipe 60 .

[0054] The natural gas pipeline system 20 of this embodiment is composed of a first gas delivery section 21, a second gas delivery section 22, a third gas delivery section 23 and valves, with a design pressure of 0.2-0.4 MPa. Natural gas is delivered to the second gas delivery section 22 and the third gas delivery section 23 through the first gas delivery section 21. Corresponding manual stop valves 2, pneumatic ball valves 3 and flame arresters 4 are installed on the first gas delivery section 21, the second gas delivery section 22 and the third gas delivery section 23.

[0055] Furthermore, if Figure 6 As shown, the air distribution system 50 includes a main pipeline 51 and a first sub-pipeline 52 and a second sub-pipeline 53. One end of the main pipeline 51 is used to let in air, and the other end is connected to the first sub-pipeline 52 and the second sub-pipeline 53 respectively. The first sub-pipeline 52 is connected to the air distribution nozzle 35 of the gas-fired atmospheric gun burner 30, and the second sub-pipeline 53 is connected to the micro-gas gun air distribution nozzle 42 of the micro-gas ignition pulverized coal burner 40.

[0056] like Figure 6 As shown, a manual butterfly valve 5 and a pneumatic butterfly valve 6 are sequentially arranged on the first auxiliary pipeline 52 along the gas flow direction; a manual butterfly valve 5 and a pneumatic butterfly valve 6 are sequentially arranged on the second auxiliary pipeline 53 along the gas flow direction.

[0057] The system of the present invention is provided with a corresponding safety protection and alarm system, that is, equipped with a natural gas detection device, which is a mature product in the market. Its detection signal is connected with the protection logic and can automatically detect natural gas. When the system stops operating or natural gas leaks, the DCS control system issues a command to quickly close the relevant valves and send out an alarm signal to purge and release the pipeline.

[0058] Furthermore, if Figure 1 As shown, a pressure transmitter 7, a flow transmitter and a temperature transmitter are also provided on the natural gas pipeline system 20 for measuring pressure, flow and temperature. A pressure transmitter 7 is also provided on the air distribution system 50 for measuring pressure.

[0059] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0060] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of multiple components or the interaction relationship of multiple components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] In the description of the present invention, it should be understood that all terms used to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be understood as a limitation on the present invention.

[0062] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A natural gas ignition device for the startup phase of a coal-fired unit, characterized in that: The invention comprises a natural gas pipeline system (20), a gas-fired atmospheric gun burner (30), a micro-gas ignition pulverized coal burner (40) and an air distribution system (50), wherein the natural gas pipeline system (20) is used to transport natural gas to the gas-fired atmospheric gun burner (30) and the micro-gas ignition pulverized coal burner (40), and the air distribution system (50) is used to transport air to the gas-fired atmospheric gun burner (30) and the micro-gas ignition pulverized coal burner (40); the gas-fired atmospheric gun burner (30) ignites a coal-fired unit by combustion of natural gas and air, and the micro-gas ignition pulverized coal burner (40) ignites a coal-fired unit by combustion of natural gas and air.

2. A natural gas ignition device for the startup phase of a coal-fired unit according to claim 1, characterized in that: The gas atmosphere gun burner (30) comprises a first high-energy ignition structure (31), an ignition air gun nozzle (32), a gas atmosphere gun main air gun (33) and an air distribution nozzle (35); the first high-energy ignition structure (31) ignites the natural gas entering from the ignition air gun nozzle (32) by means of a high-voltage electric spark, and the ignition of the natural gas ignites the natural gas entering from the gas atmosphere gun main air gun (33), thereby achieving three-stage ignition; the air distribution nozzle (35) provides air for the three-stage ignition.

3. A natural gas ignition device for the startup phase of a coal-fired unit according to claim 1, characterized in that: The micro-gas ignition pulverized coal burner (40) comprises a second high-energy ignition structure (41), a micro-gas gun air nozzle (42) and a micro-gas gun nozzle (43); the second high-energy ignition structure (41) ignites the natural gas entering the micro-gas gun nozzle (43) through a high-voltage electric spark to achieve ignition; the micro-gas gun air nozzle (42) provides air for ignition.

4. A natural gas ignition device for the startup phase of a coal-fired unit according to claim 2 or 3, characterized in that: The natural gas pipeline system (20) comprises a first gas delivery section (21), a second gas delivery section (22) and a third gas delivery section (23); one end of the first gas delivery section (21) is connected to a natural gas supply structure, and the other end is respectively connected to one end of the second gas delivery section (22) and the third gas delivery section (23); the other end of the second gas delivery section (22) is connected to the gas air gun burner (30), and the other end of the third gas delivery section (23) is connected to the micro-gas ignition pulverized coal burner (40).

5. A natural gas ignition device for the startup phase of a coal-fired unit according to claim 4, characterized in that: A gas filter (1) is provided on the first gas delivery section (21).

6. A natural gas ignition device for the startup phase of a coal-fired unit according to claim 5, characterized in that: The second gas delivery section (22) comprises a first pipeline (221), a second pipeline (222) and a third pipeline (223); one end of the first pipeline (221) is connected to the first gas delivery section (21), and the other end is respectively connected to one end of the second pipeline (222) and the third pipeline (223); the other ends of the second pipeline (222) and the third pipeline (223) are respectively connected to the ignition air gun nozzle (32) of the gas air gun burner (30) and the main air gun (33) of the gas air gun.

7. A natural gas ignition device for the startup phase of a coal-fired unit according to claim 6, characterized in that: A manual stop valve (2), a pneumatic ball valve (3) and a flame arrester (4) are sequentially arranged on the second pipeline (222) from an end away from the gas air gun burner (30) to an end close to the gas air gun burner (30), and / or a manual stop valve (2), a pneumatic ball valve (3) and a flame arrester (4) are sequentially arranged on the third pipeline (223); And / or a manual stop valve (2), a pneumatic ball valve (3) and a flame arrester (4) are sequentially arranged on the third gas delivery section (23) from an end away from the micro-gas ignition pulverized coal burner (40) to an end close to the micro-gas ignition pulverized coal burner (40).

8. A natural gas ignition device for the startup phase of a coal-fired unit according to claim 4, characterized in that: An end of the first gas transmission section (21) close to the natural gas supply structure is connected to an exhaust pipe (60); an end of the first gas transmission section (21) away from the natural gas supply structure is connected to a nitrogen filling pipe (70).

9. A natural gas ignition device for the startup phase of a coal-fired unit according to claim 8, characterized in that: The nitrogen filling pipeline (70) is provided with a manual stop valve (2).

10. A natural gas ignition device for the startup phase of a coal-fired unit according to claim 1, characterized in that: The air distribution system (50) comprises a main pipeline (51), a first auxiliary pipeline (52) and a second auxiliary pipeline (53); one end of the main pipeline (51) is used for introducing air, and the other end is respectively connected to the first auxiliary pipeline (52) and the second auxiliary pipeline (53); the first auxiliary pipeline (52) is connected to the air distribution nozzle (35) of the gas-fired atmospheric gun burner (30), and the second auxiliary pipeline (53) is connected to the micro-air gun air distribution nozzle (42) of the micro-air ignition pulverized coal burner (40).

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