Plasma combustor with adjustable combustion distance

Abstract

The invention provides a plasma combustor with an adjustable combustion distance, and relates to the technical field of plasma combustors, the plasma combustor comprises a thermocouple protection plate, the inner side of the thermocouple protection plate is provided with a secondary cylinder, the front end of the secondary cylinder is provided with a nozzle thermocouple protection tube, the front end of the nozzle thermocouple protection tube is provided with a nozzle, and the nozzle thermocouple protection tube is provided with a nozzle. The tail end of the secondary cylinder is communicated with the central cylinder, the tail end of the central cylinder is communicated with the wear-resistant sheath assembly, a central cylinder thermocouple protection tube assembly is arranged between the thermocouple protection plate and the nozzle, and the tail end of the thermocouple protection plate is fixedly connected with the outer cylinder part; the connecting plate structure can move towards the outer side through the outer rod structure in the connecting plate structure and the plasma generator and the inner cylinder structure in the middle, the plasma generator and the inner cylinder structure can move on the inner side of the center cylinder, the combustion distance during working can be adjusted according to the actual condition of the quality of coal entering a furnace, and therefore normal operation of the plasma combustor is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of plasma burners, in particular to a plasma burner with adjustable combustion distance. Background Art

[0002] The ignition and stable combustion of traditional large-scale power station pulverized coal boilers require fuel consumption. According to statistics, a 300MW pulverized coal boiler consumes about 100 tons of fuel for cold start-up. When the load is low, the oil gun needs to be started for stable combustion, and when the boiler is shut down, the oil gun needs to be started for combustion assistance. It can be seen that the amount of fuel consumed by the start-up ignition, shutdown and low-load stable combustion of thermal power station boilers is huge every year. With the increasingly tense global energy situation, countries around the world are actively implementing energy strategies for energy conservation and emission reduction; the transformation of "energy conservation and emission reduction" in the thermal power generation industry has also reached a more urgent time. According to the actual situation of traditional thermal power stations, the plasma ignition technology that uses "coal" instead of "oil" has replaced the oil or gas ignition technology and has been vigorously promoted. According to statistics, it has been applied to thousands of power boilers, saving nearly 9 million tons of oil annually. Plasma combustion technology refers to the use of DC air plasma as an ignition source to achieve oil-free ignition of the boiler without a drop of oil during cold start. Plasma has the characteristic of promoting combustion. The plasma combustion system mainly includes combustion system, air powder system, plasma generator, electrical system, plasma air system and plasma cooling water system. Plasma combustion technology has been applied to more than 200 units in China. Combined with the actual use of Jiangsu Xuzhou Power Plant expansion, plasma combustion technology is introduced. The example shows that the oil-saving effect of using plasma combustion device is very obvious, especially suitable for newly built units.

[0003] For example, patent number CN202022269015.1 is a plasma burner. The device is equipped with a jet air inlet to provide air for the flame to be generated. By arranging the jet air inlet between the coil and the processing box, it is convenient to supply oxygen to the entire device. By arranging a filter net, some coal powder with larger particles can be filtered out. The device does not process coal powder with larger particles, resulting in low utilization rate, and the device cannot conveniently adjust the combustion distance. Summary of the invention

[0004] Technical issues solved

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a plasma burner with adjustable combustion distance. Through the setting of the adjustment device structure, the user can drive the external connecting plate structure to move outward through the external power component, and the connecting plate structure can move outward through the outer rod structure and the plasma generator and inner cylinder structure in the middle. The plasma generator and the inner cylinder structure can be moved inside the central cylinder. The combustion distance during operation can be adjusted according to the actual quality of the coal entering the furnace to ensure the normal operation of the plasma burner. It can effectively solve the problem that the device in the prior art does not process the particles with larger size, resulting in low utilization rate, and the device cannot conveniently adjust the combustion distance.

[0006] Technical Solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] The present invention provides a plasma burner with adjustable combustion distance, comprising: a thermocouple protection plate, a secondary tube arranged on the inner side of the thermocouple protection plate, a nozzle thermocouple protection tube arranged at the front end of the secondary tube, a nozzle arranged at the front end of the nozzle thermocouple protection tube, the tail end of the secondary tube is connected with a central tube, the tail end of the central tube is connected with a wear-resistant sheath assembly, a central tube thermocouple protection tube assembly is arranged between the thermocouple protection plate and the nozzle, the tail end of the thermocouple protection plate is fixedly connected with an outer tube component, the outer tube component is fixedly connected with an elbow through a connecting flange, a through groove is opened on one side of the elbow, and an adjustment device is arranged in the through groove.

[0009] Furthermore, the adjustment device includes: a plasma generator, an inner cylinder, an outer rod, a flange and a connecting plate, one end of the connecting plate is fixedly connected to the outer rod, the middle part of the outer rod passes through the flange, the front end of the plasma generator is fixedly connected to the front end of the inner cylinder, the inner side of the tail end of the outer cylinder component is provided with an outer cylinder wear-resistant section, and the outer side of the wear-resistant sleeve assembly is provided with a second bolt, a second spring washer and a second washer.

[0010] Furthermore, a sandwich air ring is fixed to the outer side wall of the nozzle, an elbow outlet sealing gasket is arranged between the connecting flanges, and a first bolt, a first spring washer, a first washer and a nut are arranged between the connecting flanges.

[0011] Furthermore, the tail end of the thermocouple protection plate is fixedly connected to the outer cylinder component through a bellows flange component and a bellows sealing gasket arranged on the inner side of the bellows flange component, and the bellows flange components are connected by a third bolt, a third spring washer, a third washer and a nut.

[0012] Furthermore, the outer side of the connecting plate maintains a transmission connection with the power structure, and the outer rods are arranged in five groups in an equidistant array, the front end of the inner tube is sleeved with the tail end of the central tube, and the tail end of the nozzle thermocouple protection tube is provided with a plug-in plate, and the plug-in plate is arranged on the outer side of the central tube.

[0013] Furthermore, the wear-resistant sheath assembly is made of wear-resistant PE rubber material.

[0014] Furthermore, the third bolts are arranged in multiple groups at equal distances on the connecting flange, and the first bolts are arranged in multiple groups at equal distances on the bellows flange component.

[0015] Furthermore, a groove structure is provided in the middle of the secondary tube and the central tube, and the outer side of the outer tube component is connected with the air duct.

[0016] Furthermore, the outer rods in the adjustment device are made of stainless steel, and a plug is fixed to the outer side of each group of the outer rods, and the size of the plug is larger than the inner diameter of the through groove.

[0017] Furthermore, a plasma burner with adjustable combustion distance further comprises:

[0018] A first temperature sensor is used to detect the temperature of the pulverized coal particles in the plasma burner;

[0019] A second temperature sensor is used to detect the medium temperature of the plasma burner;

[0020] The third temperature sensor is used to detect the initial temperature of the primary air introduced into the plasma burner;

[0021] A controller and an alarm, wherein the controller is electrically connected to the first temperature sensor, the second temperature sensor, the third temperature sensor and the alarm;

[0022] The controller works based on the first temperature sensor, the second temperature sensor, the third temperature sensor and the alarm, and includes the following steps:

[0023] Step 1: According to formula (1), the detection values ​​of the first temperature sensor and the second temperature sensor, the combustion rate K of the pulverized coal in the plasma burner is calculated:

[0024]

[0025] d is the particle diameter of the coal powder, P is the partial pressure of the gas phase oxidant around the coal powder particles, C is the coal powder diffusion rate constant, X1 is the chemical reaction rate of the coal powder, X2 is the diffusion rate of the coal powder in the plasma burner, T1 is the detection value of the first temperature sensor, T2 is the detection value of the second temperature sensor, and π is 3.14;

[0026] Step 2: According to formula (2) and the detection value of the third temperature sensor, calculate the actual heat Q absorbed by the plasma burner when the air is introduced into the plasma burner and the ignition temperature is reached per unit time;

[0027] The controller compares the actual heat Q absorbed by the plasma burner when the ignition temperature is reached after air is introduced into the plasma burner within a unit time with the preset absorbed heat range. When the actual absorbed heat is lower than the preset absorbed heat range, the controller controls the alarm to sound an alarm.

[0028]

[0029] c1 is the specific heat capacity of coal powder, μ is the water content in unit volume of coal powder, λ is the excess air coefficient of primary air, T3 is the ignition temperature of the coal powder airflow in the plasma burner, T4 is the detection value of the third temperature sensor, c2 is the specific heat capacity of air, and V is the volume of air introduced into the plasma burner per unit time.

[0030] Compared with the known public technology, the technical solution provided by the present invention has the following beneficial effects:

[0031] By setting up the adjustment device structure, the user can drive the external connecting plate structure to move outward through the external power component, and the connecting plate structure can move outward through the outer rod structure and the plasma generator and inner cylinder structure in the middle, and the plasma generator and inner cylinder structure can move inside the central cylinder, and the combustion distance during operation can be adjusted according to the actual quality of the coal entering the furnace to ensure the normal operation of the plasma burner. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0033] Figure 1 It is a structural schematic diagram of the present invention;

[0034] Figure 2 It is a structural breakdown diagram of the present invention;

[0035] Figure 3 It is a top view of the structure in the present invention;

[0036] Figure 4 for Figure 3 Structural cross-section of EE in the middle;

[0037] Figure 5It is a structural cross-sectional view of the present invention;

[0038] Figure 6 for Figure 5 The structural diagram at I in the middle;

[0039] Figure 7 for Figure 5 Schematic diagram of the structure at II in the middle;

[0040] Figure 8 for Figure 5 Schematic diagram of the structure at III.

[0041] The numbers in the figure represent: 1, sandwich air ring; 2, nozzle; 3, nozzle thermocouple protection tube; 4, thermocouple protection plate; 5, secondary tube; 6, center tube; 7, center tube thermocouple protection tube assembly; 8, outer tube component; 9, outer tube wear section; 10, bellows flange component; 11, bellows sealing gasket; 12, connecting flange; 13, elbow outlet sealing gasket; 14, elbow; 141, through groove; 15, wear-resistant jacket assembly; 16. first bolt; 17. first spring washer; 18. first washer; 19. nut; 20. second bolt; 21. second spring washer; 22. second washer; 23. third bolt; 24. third spring washer; 25. third washer; 26. air duct; 27. adjustment device; 271. plasma generator; 272. inner tube; 273. outer rod; 274. plug; 275. flange; 276. connecting plate. DETAILED DESCRIPTION

[0042] 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.

[0043] The present invention will be further described below in conjunction with the embodiments.

[0044] Example 1

[0045] The embodiment of the present invention provides a plasma burner with adjustable combustion distance. Figure 1 -Attached Figure 8, including: a thermocouple protection plate 4, a secondary tube 5 is arranged on the inner side of the thermocouple protection plate 4, a nozzle thermocouple protection tube 3 is arranged at the front end of the secondary tube 5, a nozzle 2 is arranged at the front end of the nozzle thermocouple protection tube 3, the tail end of the secondary tube 5 is connected with the center tube 6, the tail end of the center tube 6 is connected with the wear-resistant sleeve assembly 15, a center tube thermocouple protection tube assembly 7 is arranged between the thermocouple protection plate 4 and the nozzle 2, the tail end of the thermocouple protection plate 4 is fixedly connected with the outer tube component 8, the outer tube component 8 is connected and fixed to the elbow 14 through the connecting flange 12, a through groove 141 is opened on one side of the elbow 14, and an adjustment device 27 is arranged in the through groove 141.

[0046] Optionally, the adjustment device 27 includes: a plasma generator 271, an inner tube 272, an outer rod 273, a flange 275 and a connecting plate 276. The plasma generator 271 and the inner tube structure can be moved inside the central tube, and the combustion distance during operation can be adjusted according to the actual quality of the coal entering the furnace to ensure the normal operation of the plasma burner; one end of the connecting plate 276 is fixedly connected to the outer rod 273, the middle part of the outer rod 273 passes through the flange 275, and the plasma generator 271 The front end is fixedly connected to the front end of the inner cylinder 272, and the inner side of the tail end of the outer cylinder component 8 is provided with an outer cylinder wear-resistant section 9. The user can drive the external connecting plate structure to move outward through an external power component, and the connecting plate structure can move outward through the outer rod structure and the middle plasma generator 271 and the inner cylinder structure. The outer cylinder wear-resistant section 9 structure can increase the wear resistance and friction therein. The outer side of the wear-resistant sleeve assembly 15 is provided with a second bolt 20, a second spring washer 21 and a second washer 22.

[0047] The beneficial effects of the above technical solution are as follows: through the setting of the adjustment device structure, the user can drive the external connecting plate structure to move outward through the external power component, and the connecting plate structure can move outward through the outer rod structure and the plasma generator 271 and the inner cylinder structure in the middle, wherein the plasma generator 271 and the inner cylinder structure can be moved inside the central cylinder, and the combustion distance during operation can be adjusted according to the actual quality of the coal entering the furnace to ensure the normal operation of the plasma burner; it can effectively solve the problem in the prior art that the device does not process larger particles, resulting in low utilization rate, and the device cannot conveniently adjust the combustion distance.

[0048] Example 2

[0049] On the basis of Example 1, Figure 1-8As shown, a sandwich air ring 1 is fixed to the outer wall of the nozzle 2, an elbow outlet sealing gasket 13 is arranged between the connecting flanges 12, a first bolt 16, a first spring washer 17, a first washer 18 and a nut 19 are arranged between the connecting flanges 12, and a combined connection is made through the connecting flange 12-first bolt 16-first spring washer 17-first washer 18-nut 19.

[0050] Optionally, the tail end of the thermocouple protection plate 4 is fixedly connected to the outer cylinder component 8 through a bellows flange component 10 and a bellows sealing gasket 11 arranged on the inner side of the bellows flange component 10, and the bellows flange components 10 are connected by a third bolt 23, a third spring washer 24, a third washer 25 and a nut 19, wherein the bellows flange component 10 is combined and connected and fixed by a third bolt 23-a third spring washer 24-a third washer 25 and a nut 19; by adjusting the combustion distance, it is used in large-scale chemical and boiler fields, and by adding a multiphase AC plasma generator at the burner nozzle, the thermal cracking of natural gas can be enhanced in advance, the flame "blackness" can be increased, and the flame radiation capacity can be improved; at the same time, the isotopes of hydrogen produced by the cracking can be stimulated to fuse in this electric field, and even a trace amount can generate considerable heat, thereby increasing the temperature of the flame, thereby achieving the purpose of saving 10-20% of energy.

[0051] Optionally, the outer side of the connecting plate 276 maintains a transmission connection with the power structure, and the outer rods 273 are arranged in five groups in an equidistant array; the combustion distance of the plasma burner is restored from one side to the other side, and adjusted by the length of the outer rods 273, so as to ensure the normal operation of the plasma burner; the front end of the inner tube 272 is sleeved with the rear end of the center tube 6, and the rear end of the nozzle thermocouple protection tube 3 is provided with a plug-in plate, and the plug-in plate is arranged on the outer side of the center tube 6.

[0052] Optionally, the wear-resistant sheath assembly 15 is made of wear-resistant PE rubber material.

[0053] Optionally, a plurality of groups of the third bolts 23 are equidistantly arranged on the connecting flange 12 , and a plurality of groups of the first bolts 16 are equidistantly arranged on the bellows flange component 10 .

[0054] Optionally, a groove structure is provided in the middle of the secondary tube 5 and the central tube 6; the adjusting device 27 structure can drive the external connecting plate 276 structure to move outward through an external power component, and the connecting plate 276 structure can move outward through the outer rod 273 structure and the plasma generator 271 and inner tube 272 structure in the middle, and the plasma generator 271 and inner tube 272 structure can move on the inner side of the central tube 6, and the combustion distance during operation can be adjusted according to the actual quality of the coal entering the furnace to ensure the normal operation of the plasma burner.

[0055] Therefore, when the dry ash-free volatile matter index of the coal entering the furnace becomes significantly larger, the plasma ignition effect is too strong and it is easy to cause overheating and burning inside the burner, the adjustment device 27 of the installed plasma burner is removed, and the combustion distance of the plasma burner can be restored from one side to the other side, and the length of the outer rod 273 can be adjusted to ensure the normal operation of the plasma burner.

[0056] Optionally, the outer rod 273 in the adjustment device 27 is made of stainless steel, and a plug 274 is fixed to the outside of each group of the outer rods 273, and the size of the plug 274 is larger than the inner diameter of the through groove 141; the plug 274 structure prevents the outer rod 273 from moving outward excessively, thereby achieving a protective effect, and the outer side of the outer cylinder component 8 remains connected to the air duct 26.

[0057] Example 3

[0058] Based on Embodiment 1-2, a plasma burner with adjustable combustion distance further includes:

[0059] A first temperature sensor is used to detect the temperature of the pulverized coal particles in the plasma burner;

[0060] A second temperature sensor is used to detect the medium temperature of the plasma burner;

[0061] The third temperature sensor is used to detect the initial temperature of the primary air introduced into the plasma burner;

[0062] A controller and an alarm, wherein the controller is electrically connected to the first temperature sensor, the second temperature sensor, the third temperature sensor and the alarm;

[0063] The controller works based on the first temperature sensor, the second temperature sensor, the third temperature sensor and the alarm, and includes the following steps:

[0064] Step 1: According to formula (1), the detection values ​​of the first temperature sensor and the second temperature sensor, the combustion rate K of the pulverized coal in the plasma burner is calculated:

[0065]

[0066] d is the particle diameter of the coal powder, P is the partial pressure of the gas phase oxidant around the coal powder particles (referring to the partial pressure generated by the gas phase oxidant (such as oxygen) in the environment where the coal powder particles are located during the coal powder combustion process. This partial pressure is a component of the total pressure of the gas phase oxidant, reflecting the concentration and activity of the oxidant around the coal powder particles), C is the coal powder diffusion rate constant, X1 is the chemical reaction rate of the coal powder, X2 is the diffusion rate of the coal powder in the plasma burner, T1 is the detection value of the first temperature sensor, T2 is the detection value of the second temperature sensor, and π is 3.14;

[0067] Step 2: According to formula (2) and the detection value of the third temperature sensor, calculate the actual heat Q absorbed by the plasma burner when the air is introduced into the plasma burner and the ignition temperature is reached per unit time;

[0068] The controller compares the actual heat Q absorbed by the plasma burner when the ignition temperature is reached after air is introduced into the plasma burner within a unit time with the preset absorbed heat range. When the actual absorbed heat is lower than the preset absorbed heat range, the controller controls the alarm to sound an alarm.

[0069]

[0070] c1 is the specific heat capacity of coal powder, μ is the water content in unit volume of coal powder, λ is the excess air coefficient of primary air (the ratio of the actual amount of air supplied for fuel combustion to the theoretical amount of air, with a value range of 0.88-1.11), T3 is the ignition temperature of the coal powder airflow in the plasma burner, T4 is the detection value of the third temperature sensor, c2 is the specific heat capacity of air, and V is the volume of air introduced into the plasma burner per unit time.

[0071] The beneficial effects of the above technical solution are as follows: the controller calculates the combustion rate of the pulverized coal in the plasma burner based on the formula (1), the detection values ​​of the first temperature sensor and the second temperature sensor, and comprehensively considers the particle diameter of the pulverized coal, the partial pressure of the gas phase oxidant around the pulverized coal particles, the pulverized coal diffusion rate constant, the chemical reaction rate of the pulverized coal, and the diffusion rate of the pulverized coal in the plasma burner, so that the calculation result is more accurate and reliable;

[0072] Then, according to formula (2) and the detection value of the third temperature sensor, the specific heat capacity of the coal powder, the water content per unit volume of the coal powder, the excess air coefficient of the primary air, the specific heat capacity of the air, and the volume of the air introduced into the plasma burner per unit time are comprehensively considered to calculate the actual heat absorbed by the plasma burner when the air is introduced into the plasma burner to reach the ignition temperature per unit time, so that the calculation result is more accurate and reliable;

[0073] The controller controls the operation of the first temperature sensor, the second temperature sensor and the third temperature sensor. The controller compares the actual heat absorbed by the plasma burner when the ignition temperature is reached after air is introduced into the plasma burner within a unit time with the preset absorbed heat range. When the actual absorbed heat is lower than the preset absorbed heat range, the controller controls the alarm to sound an alarm, reminding the staff to observe the combustion of the coal powder in the plasma burner in time or check whether the plasma burner is operating normally, thereby meeting the user's demand for a plasma burner with an adjustable combustion distance.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A plasma burner with adjustable combustion distance, characterized in that: include: A thermocouple protection plate (4), a secondary tube (5) is arranged on the inner side of the thermocouple protection plate (4), a nozzle thermocouple protection tube (3) is arranged at the front end of the secondary tube (5), a nozzle (2) is arranged at the front end of the nozzle thermocouple protection tube (3), the tail end of the secondary tube (5) is connected to the central tube (6), the tail end of the central tube (6) is connected to the wear-resistant sleeve assembly (15), a central tube thermocouple protection tube assembly (7) is arranged between the thermocouple protection plate (4) and the nozzle (2), the tail end of the thermocouple protection plate (4) is fixedly connected to the outer tube component (8), the outer tube component (8) is connected and fixed to the elbow (14) through a connecting flange (12), a through groove (141) is opened on one side of the elbow (14), and an adjustment device (27) is arranged in the through groove (141).

2. The plasma burner with adjustable combustion distance according to claim 1, characterized in that: The adjustment device (27) comprises: a plasma generator (271), an inner cylinder (272), an outer rod (273), a flange (275) and a connecting plate (276); one end of the connecting plate (276) is fixedly connected to the outer rod (273); the middle of the outer rod (273) passes through the flange (275); the front end of the plasma generator (271) is fixedly connected to the front end of the inner cylinder (272); the inner side of the rear end of the outer cylinder component (8) is sleeved with an outer cylinder wear-resistant section (9); and the outer side of the wear-resistant sleeve assembly (15) is provided with a second bolt (20), a second spring washer (21) and a second washer (22).

3. The plasma burner with adjustable combustion distance according to claim 1, characterized in that: A sandwich air ring (1) is fixed to the outer wall of the nozzle (2), an elbow outlet sealing gasket (13) is arranged between the connecting flanges (12), and a first bolt (16), a first spring washer (17), a first washer (18) and a nut (19) are arranged between the connecting flanges (12).

4. The plasma burner with adjustable combustion distance according to claim 1, characterized in that: The tail end of the thermocouple protection plate (4) is fixedly connected to the outer cylinder component (8) via a bellows flange component (10) and a bellows sealing gasket (11) arranged on the inner side of the bellows flange component (10), and the bellows flange components (10) are connected via a third bolt (23), a third spring washer (24), a third washer (25) and a nut (19).

5. The plasma burner with adjustable combustion distance according to claim 2, characterized in that: The outer side of the connecting plate (276) is in transmission connection with the power structure, and the outer rods (273) are arranged in five groups in an equidistant array. The front end of the inner tube (272) is sleeved with the rear end of the central tube (6), and the rear end of the nozzle thermocouple protection tube (3) is provided with an insertion plate, and the insertion plate is arranged on the outer side of the central tube (6).

6. The plasma burner with adjustable combustion distance according to claim 1, characterized in that: The wear-resistant sheath component (15) is made of wear-resistant PE rubber material.

7. The plasma burner with adjustable combustion distance according to claim 4, characterized in that: The third bolts (23) are arranged in multiple groups at equal intervals on the connecting flange (12), and the first bolts (16) are arranged in multiple groups at equal intervals on the bellows flange component (10).

8. The plasma burner with adjustable combustion distance according to claim 1, characterized in that: A groove structure is provided in the middle of the secondary cylinder (5) and the central cylinder (6), and the outer side of the outer cylinder component (8) is connected to the air duct (26).

9. The plasma burner with adjustable combustion distance according to claim 2, characterized in that: The outer rods (273) in the adjustment device (27) are made of stainless steel, and a plug (274) is fixed on the outside of each group of the outer rods (273), and the size of the plug (274) is larger than the inner diameter of the through groove (141).

10. The plasma burner with adjustable combustion distance according to claim 1, characterized in that: Also includes: A first temperature sensor is used to detect the temperature of the pulverized coal particles in the plasma burner; A second temperature sensor is used to detect the medium temperature of the plasma burner; The third temperature sensor is used to detect the initial temperature of the primary air introduced into the plasma burner; A controller and an alarm, wherein the controller is electrically connected to the first temperature sensor, the second temperature sensor, the third temperature sensor and the alarm; The controller works based on the first temperature sensor, the second temperature sensor, the third temperature sensor and the alarm, and includes the following steps: Step 1: According to formula (1), the detection values ​​of the first temperature sensor and the second temperature sensor, the combustion rate K of the pulverized coal in the plasma burner is calculated: d is the particle diameter of the coal powder, P is the partial pressure of the gas phase oxidant around the coal powder particles, C is the coal powder diffusion rate constant, X1 is the chemical reaction rate of the coal powder, X2 is the diffusion rate of the coal powder in the plasma burner, T1 is the detection value of the first temperature sensor, T2 is the detection value of the second temperature sensor, and π is 3.14; Step 2: Calculate the actual heat Q absorbed by the plasma burner when the ignition temperature is reached after air is introduced into the plasma burner per unit time according to formula (2), the third temperature sensor and the detection value of the third temperature sensor; The controller compares the actual heat Q absorbed by the plasma burner when the ignition temperature is reached after air is introduced into the plasma burner within a unit time with the preset absorbed heat range. When the actual absorbed heat is lower than the preset absorbed heat range, the controller controls the alarm to sound an alarm. c1 is the specific heat capacity of coal powder, μ is the water content in unit volume of coal powder, λ is the excess air coefficient of primary air, T3 is the ignition temperature of the coal powder airflow in the plasma burner, T4 is the detection value of the third temperature sensor, c2 is the specific heat capacity of air, and V is the volume of air introduced into the plasma burner per unit time.

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