Combustion stabilizing device and using method

Abstract

The invention discloses a stable combustion device and a using method.The stable combustion device comprises a body, a pulverized coal pipe assembly, a ventilation pipe assembly and a combustion assembly, the body is provided with a cavity, the cavity extends in the first direction, one end of the cavity is provided with a backflow area, the pulverized coal pipe assembly is arranged in the cavity and extends in the first direction, and one end of the pulverized coal pipe assembly is provided with a coal outlet; the coal outlet is communicated with the backflow area so as to introduce pulverized coal into the backflow area, the ventilation pipe assembly is arranged in the cavity and arranged outside the pulverized coal pipe assembly in a sleeving mode, an air outlet is formed in one end of the ventilation pipe assembly and communicated with the backflow area so as to supply air to the backflow area, and the combustion assembly is arranged at one end of the ventilation pipe assembly and located at one end of the cavity and provided with a combustion chamber. The backflow area is formed in the combustion chamber, the air outlet communicates with the combustion chamber, and the coal outlet is located in the combustion chamber. The stable combustion device is suitable for different coal types, high in adaptability and stable in combustion.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion stabilizers, and in particular to a combustion stabilizer and a use method thereof. Background Art

[0002] Deep peak-shaving operation of coal-fired power units is an important measure to promote the construction of a new energy system and steadily achieve the "dual carbon" goals. In this context, it is urgent to develop low-load stable combustion technology with good operating economy and reliability.

[0003] In the related technology, ignition and combustion stabilization technologies such as plasma ignition are usually used to achieve the combustion of coal powder. However, plasma ignition technology is only applicable to a small range of coal types, and the combustion is unstable, resulting in incomplete combustion of coal powder. It also has high cost and does not have good operating economy and reliability. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of the present invention provides a combustion stabilization device and a method of use.

[0006] The combustion stabilization device of the embodiment of the present invention comprises:

[0007] A body, wherein the body has a chamber, the chamber extends along a first direction, and one end of the chamber has a reflow zone;

[0008] a pulverized coal pipe assembly, the pulverized coal pipe assembly being arranged in the chamber and extending along the first direction, one end of the pulverized coal pipe assembly having a coal outlet, the coal outlet being in communication with the recirculation zone so as to allow pulverized coal to flow into the recirculation zone;

[0009] A ventilation pipe assembly, the ventilation pipe assembly is arranged in the chamber and sleeved outside the pulverized coal pipe assembly, one end of the ventilation pipe assembly has an air outlet, the air outlet is connected to the recirculation area to supply air to the recirculation area, and the ventilation pipe assembly can adjust the air volume entering the recirculation area;

[0010] A combustion assembly is provided at one end of the ventilation pipe assembly and located at one end of the chamber, the combustion assembly has a combustion chamber, the recirculation zone is formed in the combustion chamber, the air outlet is connected to the combustion chamber, and the coal outlet is located in the combustion chamber.

[0011] In the combustion stabilizing device of the embodiment of the present invention, the coal powder enters the combustion chamber from the coal outlet after passing through the coal powder pipe assembly. At the same time, the combustion chamber is ventilated through the ventilation pipe assembly to assist the combustion of the coal powder and increase the temperature of the combustion chamber, thereby enhancing the rapid heating and ignition of the coal powder and the stable combustion. The coal powder that is then introduced into the combustion chamber is ignited to achieve coal-to-coal ignition, thereby improving the stability of coal powder combustion and the combustion efficiency of coal powder. The air volume entering the combustion chamber is adjusted through the ventilation pipe assembly to adapt to the combustion of different types of coal, thereby improving the coal type adaptability of the combustion stabilizing device, so that the combustion stabilizing device of the embodiment of the present invention has good operating economy and reliability.

[0012] In some embodiments, the pulverized coal pipe assembly comprises:

[0013] A pulverized coal pipe, the pulverized coal pipe extending along the first direction and having a first flow channel and a second flow channel arranged in sequence from the inside to the outside, and the first flow channel and the second flow channel both have pulverized coal;

[0014] A coal outlet component, wherein the coal outlet component is arranged at one end of the coal powder pipe, the coal outlet component has a first channel and a second channel, the coal outlet is formed on the coal outlet component, the coal outlet is opened along the first direction, the first channel connects the first flow channel and the coal outlet, the coal powder in the first flow channel can flow out from the coal outlet after passing through the first channel, the second channel connects the second flow channel and the coal outlet, the coal powder in the second flow channel can flow out from the coal outlet through the second channel, and an angle a is formed between the flow direction of the coal powder flowing out of the first channel and the flow direction of the coal powder flowing out of the second channel.

[0015] In some embodiments, the angle a is adjustable.

[0016] In some embodiments, the ventilation duct assembly comprises:

[0017] a first air duct, a second air duct and a third air duct, wherein the first air duct is sleeved outside the pulverized coal pipe assembly, the first air duct, the second air duct and the third air duct are arranged in sequence from the inside to the outside, and the air outlet comprises a first air outlet connecting the first air duct and the combustion chamber, a second air outlet connecting the second air duct and the combustion chamber, and a third air outlet connecting the third air duct and the combustion chamber;

[0018] A first regulating valve, a second regulating valve and a third regulating valve, wherein the first regulating valve is arranged at the air inlet of the first air duct, and is used to adjust the air volume passing into the first air duct, the second regulating valve is arranged at the air inlet of the second air duct, and is used to adjust the air volume passing into the second air duct, and the third regulating valve is arranged at the air inlet of the third air duct, and is used to adjust the air volume passing into the third air duct.

[0019] In some embodiments, the ventilation duct assembly also includes a first flow guide, a second flow guide and a third flow guide, the first flow guide is arranged at the first air outlet to adjust the wind direction of the wind passing from the first air duct into the combustion chamber, the second flow guide is arranged at the second air outlet to adjust the wind direction of the wind passing from the second air duct into the combustion chamber, and the third flow guide is arranged at the third air outlet to adjust the wind direction of the wind passing from the third air duct into the combustion chamber.

[0020] In some embodiments, the combustion assembly comprises:

[0021] A reflux cylinder, the reflux cylinder is arranged at one end of the third air duct and located at one end of the chamber, and the combustion chamber is formed in the inner cavity of the reflux cylinder;

[0022] A reinforcing cylinder, which is sleeved outside the reflux cylinder and is used to enhance the structural strength of the reflux cylinder;

[0023] An injection tube, wherein the injection tube is arranged at one end of the main body, the injection tube has an injection cavity connected to the chamber, the injection cavity is connected to the combustion cavity, and the diameter of the injection cavity gradually decreases along the first direction from the end of the injection tube adjacent to the main body to the end of the injection tube away from the main body.

[0024] In some embodiments, the cross-sectional area of ​​the combustion chamber gradually increases along the first direction from an end of the recirculation cylinder adjacent to the third air duct to an end of the recirculation cylinder adjacent to the injection cylinder.

[0025] In some embodiments, the main body includes a cylinder and an extension section, the cylinder extends along the first direction, the chamber is formed in the cylinder, one end of the cylinder has a through hole, the through hole is connected to the chamber, one end of the extension section is arranged at one end of the cylinder and extends along the edge of the through hole in a direction away from the cylinder, the other end of the extension section is connected to one end of the injection tube, an air distribution channel is formed between the inner circumference of the cylinder and the outer circumference of the third air duct, there is wind in the air distribution channel, the reinforcement tube extends from one end adjacent to the injection tube to the other end of the extension section, a rectifying channel is formed between the inner circumference of the extension section and the outer circumference of the reinforcement tube, the rectifying channel connects the air distribution channel and the injection chamber.

[0026] In some embodiments, a cross-sectional area of ​​the extension segment is smaller than a cross-sectional area of ​​the cylinder, and the cross-sectional area of ​​the extension segment gradually decreases from one end of the extension segment to the other end of the extension segment along the first direction.

[0027] The method for using the combustion stabilization device according to the embodiment of the present invention comprises:

[0028] The pulverized coal is introduced into the reflux zone through the pulverized coal pipe assembly, and the pulverized coal is judged according to its type to be a low-volatile, difficult-to-combustible coal or a high-ash, easily combustible coal;

[0029] When the pulverized coal is a low-volatile, flame-retardant type of coal, the amount of pulverized coal in the first flow channel is increased, and the amount of pulverized coal in the second flow channel is reduced. The pulverized coal in the first flow channel and the pulverized coal in the second flow channel are discharged through the coal outlet, and the angle a is gradually reduced, so that the radial velocity component of the pulverized coal flowing in the recirculation zone is reduced, and the axial velocity component is increased. At the same time, the first air outlet is closed, the opening of the second air outlet is reduced, and the opening of the third air outlet is increased;

[0030] When the pulverized coal is a high-ash, flammable type, the amount of pulverized coal in the first flow channel is reduced, and the amount of pulverized coal in the second flow channel is increased. The pulverized coal in the first flow channel and the pulverized coal in the second flow channel are discharged through the coal outlet, and the angle a gradually increases, so that the radial velocity component of the pulverized coal flowing in the recirculation zone increases and the axial velocity component decreases. At the same time, the opening of the first air outlet is increased, the second air outlet is opened, and the third air outlet is closed.

[0031] The method for using the combustion stabilizing device according to the embodiment of the present invention improves the adaptability of the combustion stabilizing device to different types of coals and has a simple operation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 4 is a front view of a combustion stabilizing device according to an embodiment of the present invention.

[0033] Figure 2 It is a left side view of the combustion stabilizing device according to an embodiment of the present invention.

[0034] Figure 3 4 is a cross-sectional view of a combustion stabilizing device according to an embodiment of the present invention.

[0035] Figure 4 yes Figure 3 Enlarged schematic diagram of part A.

[0036] Figure 5 yes Figure 3 Schematic diagram of the enlarged portion B.

[0037] Figure 6 yes Figure 3 The enlarged schematic diagram of part C in the figure,

[0038] Figure 7 yes Figure 1 Sectional view of AA.

[0039] Figure 8 yes Figure 1 Cross-sectional view of BB.

[0040] Fig. 9It is a schematic diagram of a coal discharging part of a combustion stabilizing device according to an embodiment of the present invention.

[0041] Figure numerals: 1, body; 11, chamber; 12, recirculation zone; 13, cylinder; 131, perforation; 14, extension section; 15, air distribution channel; 16, air inlet pipe; 17, rectification channel; 2, pulverized coal pipe assembly; 21, pulverized coal pipe; 211, first pulverized coal pipe; 212, second pulverized coal pipe; 22, coal outlet; 221, first channel; 222, second channel; 223, protrusion; 224, first guide; 225, extension; 226, second guide; 227, coal outlet; 23, first flow channel; 24, second flow channel; 3, ventilation pipe assembly; 311, first air channel; 312, second air channel; 313, third air channel; 32, air outlet; 321, first air outlet; 322, second air outlet; 323, third air outlet; 331, fixed pipe; 332, first air duct; 333, second air duct; 334, third air duct; 351, first regulating valve; 352, second regulating valve; 353, third regulating valve; 361, first branch pipe; 3611, first air inlet; 362, second branch pipe; 3621, second air inlet; 363, third branch pipe; 3631, third air inlet; 371, first guide piece; 372, second guide piece; 373, third guide piece; 4, combustion assembly; 41, reflux tube; 411, combustion chamber; 42, reinforcement tube; 43, injection tube; 431, injection chamber. DETAILED DESCRIPTION

[0042] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0043] like Figure 1-9 As shown, an embodiment of the present invention provides a combustion stabilization device and a method for using the same.

[0044] The following first describes a combustion stabilizing device according to an embodiment of the present invention.

[0045] The combustion stabilization device of the embodiment of the present invention comprises a body 1, a pulverized coal pipe assembly 2, a ventilation pipe assembly 3 and a combustion assembly 4. The body 1 extends along a first direction (eg Figure 3 The left and right directions shown in the figure) and have a chamber 11, the chamber 11 extends along the first direction, and one end of the chamber 11 (as shown in the figure) Figure 3 The right end of the chamber 11 shown in FIG. 1 has a reflow zone 12, such as Figure 3 As shown, the extension length of the recirculation zone 12 in the first direction is L, and the radial length of the recirculation zone 12 in the radial direction is D.

[0046] The pulverized coal pipe assembly 2 is disposed in the chamber 11 and extends along a first direction. Figure 3 The right end of the pulverized coal pipe assembly 2 shown in the figure extends into the recirculation zone 12 and has a coal outlet 227 , which is connected to the recirculation zone 12 to allow pulverized coal to be introduced into the recirculation zone 12 .

[0047] The ventilation pipe assembly 3 is arranged in the chamber 11 and is sleeved outside the coal powder pipe assembly 2. One end of the ventilation pipe assembly 3 (such as Figure 3 The right end of the ventilation duct assembly 3 shown extends into the recirculation zone 12 and has an air outlet 32, which is connected to the recirculation zone 12 to supply air to the recirculation zone 12. The ventilation duct assembly 3 can adjust the air volume entering the recirculation zone 12.

[0048] The combustion assembly 4 is arranged at one end of the ventilation pipe assembly 3 and located at one end of the chamber 11. The combustion assembly 4 has a combustion chamber 411. The recirculation zone 12 is formed in the combustion chamber 411. The air outlet 32 ​​is connected to the combustion chamber 411. The coal outlet 227 is located in the combustion chamber 411.

[0049] In the combustion stabilizing device of the embodiment of the present invention, the coal powder passes through the coal powder pipe assembly 2 and enters the combustion chamber 411 from the coal outlet 227. At the same time, the combustion chamber 411 is ventilated through the ventilation pipe assembly 3 to assist the combustion of the coal powder and increase the temperature of the combustion chamber 411, thereby enhancing the rapid heating and ignition of the coal powder and the stable combustion. The coal powder is then ignited and introduced into the combustion chamber 411 to achieve coal-to-coal ignition, thereby improving the stability of coal powder combustion and the combustion efficiency of coal powder. The air volume entering the combustion chamber 411 is adjusted through the ventilation pipe assembly 3 to adapt to the combustion of different types of coal, thereby improving the coal type adaptability of the combustion stabilizing device, so that the combustion stabilizing device of the embodiment of the present invention has good operating economy and reliability.

[0050] In some embodiments, the pulverized coal pipe assembly 2 includes a pulverized coal pipe 21 and a coal outlet 22. The pulverized coal pipe 21 extends along a first direction and has a first flow channel 23 and a second flow channel 24 arranged from inside to outside, and both the first flow channel 23 and the second flow channel 24 have pulverized coal.

[0051] Specifically, the pulverized coal pipe 21 includes a first pulverized coal pipe 211 and a second pulverized coal pipe 212, both of which are slender straight pipe structures. The right end of the first pulverized coal pipe 211 extends into the chamber 11, and the first flow channel 23 is formed in the first pulverized coal pipe 211. The inner diameter of the second pulverized coal pipe 212 is larger than the outer diameter of the first pulverized coal pipe 211. The second pulverized coal pipe 212 is sleeved outside the first pulverized coal pipe 211, the right end of the second pulverized coal pipe 212 extends into the chamber 11, the right end of the first pulverized coal pipe 211 extends out of the right end of the second pulverized coal pipe 212, and the second flow channel 24 is formed between the inner circumference of the second pulverized coal pipe 212 and the outer circumference of the first pulverized coal pipe 211. The first pulverized coal pipe 211 and the second pulverized coal pipe 212 are coaxially arranged so that the second flow channel 24 is an annular flow channel.

[0052] The coal outlet 22 is provided at one end of the pulverized coal pipe 21. The coal outlet 22 has a first channel 221 and a second channel 222. A coal outlet 227 is formed on the coal outlet 22. The coal outlet 227 is opened along a first direction. The first channel 221 connects the first flow channel 23 and the coal outlet 227. The pulverized coal in the first flow channel 23 can flow out of the coal outlet 227 through the first channel 221. The second channel 222 connects the second flow channel 24 and the coal outlet 227. The pulverized coal in the second flow channel 24 can flow out of the coal outlet 227 through the second channel 222. The flow direction of the pulverized coal flowing out of the first channel 221 and the flow direction of the pulverized coal flowing out of the second channel 222 form an angle a.

[0053] Specifically, the coal outlet member 22 includes a protrusion 223, a first guide portion 224, an extension portion 225, and a second guide portion 226. The left end of the protrusion 223 is arranged at the right end of the second pulverized coal pipe 212 and is arranged around the circumference of the second pulverized coal pipe 212, and the right end of the protrusion 223 extends in the first direction away from the second pulverized coal pipe 212 and is located on the left side of the right end of the first pulverized coal pipe 211. The protrusion 223 is an axisymmetric structure with a central hole, and the inner diameter of the central hole of the protrusion 223 is the same as the inner diameter of the second pulverized coal pipe 212.

[0054] Specifically, the outer contour of the protrusion 223 is truncated cone-shaped, and the cross-sectional area of ​​the outer contour of the protrusion 223 gradually increases from the right end of the protrusion 223 to the left end of the protrusion 223, so that the outer peripheral surface of the protrusion 223 is an inclined surface, and the diameter of the outer contour of the left end of the protrusion 223 is greater than the outer diameter of the second pulverized coal pipe 212.

[0055] The first guide portion 224 is an axisymmetric structure with a central hole. The first guide portion 224 is annular. The inner circumference of the first guide portion 224 is arranged around the right end of the first pulverized coal pipe 211. The outer circumference of the first guide portion 224 extends outward. The outer circumference of the first guide portion 224 is located on the outside of the protrusion 223.

[0056] The right end of the extension portion 225 is arranged around the outer peripheral surface of the first guide portion 224, and the left end of the extension portion 225 extends along the first direction toward the protrusion 223. The extension portion 225 is located on the outer side of the protrusion 223, and the inner peripheral surface of the extension portion 225 and the outer peripheral surface of the protrusion 223 are arranged at intervals. The second channel 222 is formed between the outer peripheral surface of the protrusion 223 and the inner peripheral surfaces of the first guide portion 224 and the extension portion 225.

[0057] Specifically, the outer circumferential contour of the extension portion 225 is cylindrical, and the inner circumferential contour of the extension portion 225 is truncated cone-shaped. The cross-section of the inner circumferential contour of the extension portion 225 gradually increases from the right end of the extension portion 225 to the left end of the extension portion 225, so that the inner circumferential surface of the extension portion 225 is an inclined surface and is adapted to the outer circumferential surface of the protrusion 223, so that the flow direction of the pulverized coal airflow ejected through the second channel 222 can form an angle with the flow direction of the pulverized coal airflow ejected from the first channel 221.

[0058] Specifically, the second channel 222 can guide the coal powder airflow flowing through it into a conical annular jet for high-speed ejection, the diameter of the conical coal powder jet gradually increases from right to left, and the flow direction of this part of the conical coal powder jet injected into the recirculation zone 12 is opposite to the flow direction of the coal powder airflow in the second flow channel 24.

[0059] The second guide portion 226 is a hat-shaped axially symmetrical structure. The second guide portion 226 is coaxially arranged with the first guide portion 224 and is covered at the right end of the first guide portion 224. The left end of the second guide portion 226 is connected to the outer circumference of the second coal powder pipe 212. The coal outlet 227 is formed at the left end of the second guide portion 226 and is opened along the first direction. The second guide portion 226 has an inner cavity, and the protrusion 223, the first guide portion 224 and the extension portion 225 are all located in the inner cavity. The first channel 221 is formed between the outer circumference of the first guide portion 224 and the extension portion 225 and the inner circumference of the second guide portion 226.

[0060] Specifically, the first channel 221 can guide the coal powder airflow passing through it to be ejected at high speed as an annular jet with a constant diameter, and the flow direction of this part of the annular coal powder jet with a constant diameter injected into the recirculation zone 12 is opposite to its flow direction in the first coal powder pipe 211. An angle a is formed between the central axis of one end of the second channel 222 adjacent to the coal outlet 227 and the central axis of the coal outlet 227.

[0061] Specifically, there are a plurality of coal outlets 227 , and the plurality of coal outlets 227 are arranged at intervals in the circumferential direction around the left end surface of the second guide portion 226 .

[0062] In some embodiments, the central axis of the protrusion 223, the central axis of the first guide portion 224 and the central axis of the second guide portion 226 are collinear, ensuring that the annular pulverized coal jet ejected at high speed from the first channel 221 and the conical annular pulverized coal jet ejected at high speed from the second channel 222 are evenly distributed.

[0063] In some embodiments, the size of the angle a is adjustable.

[0064] Specifically, the value range of the angle a is: 0≤a<90°. When there is no coal powder discharged from the coal outlet 227 in the second flow channel 24, and there is coal powder discharged from the coal outlet 227 in the first flow channel 23, the coal powder is ejected along the first direction, and the angle a is 0. When there is coal powder discharged from the coal outlet 227 in the second flow channel 24, and there is no coal powder discharged from the coal outlet 227 in the first flow channel 23, the coal powder is ejected along the central axis direction of the outlet of the second channel 222, and the angle 0<a<90°.

[0065] In some embodiments, the ventilation pipe assembly 3 includes a first air duct 311, a second air duct 312, and a third air duct 313. The first air duct 311 is sleeved outside the coal powder pipe assembly 2, and the first air duct 311, the second air duct 312, and the third air duct 313 are arranged from the inside to the outside. The air outlet 32 ​​includes a first air outlet 321, a second air outlet 322, and a third air outlet 323. The first air outlet 321 connects the first air duct 311 and the combustion chamber 411. The second air outlet 322 connects the second air duct 312 and the combustion chamber 411. The third air outlet 323 connects the third air duct 313 and the combustion chamber 411.

[0066] Specifically, the ventilation pipe assembly 3 includes a fixed pipe 331, a first air pipe 332, a second air pipe 333 and a third air pipe 334 arranged in sequence from the inside to the outside. The fixed pipe 331 is sleeved on the second coal powder pipe 212 and connected to the second coal powder pipe 212, and the second coal powder pipe 212, the fixed pipe 331, the first air pipe 332, the second air pipe 333 and the third air pipe 334 are coaxially arranged.

[0067] The first air duct 311 is formed between the outer circumference of the fixed tube 331 and the inner circumference of the first air duct 332, so that the annular airflow flowing out of the first air duct 311 is arranged around the inner circumference of the first air duct 332. The second air duct 312 is formed between the outer circumference of the first air duct 332 and the inner circumference of the second air duct 333, so that the annular airflow flowing out of the second air duct 312 is arranged around the inner circumference of the second air duct 333. The third air duct 313 is formed between the outer circumference of the second air duct 333 and the inner circumference of the third air duct 334, so that the annular airflow flowing out of the third air duct 313 is arranged around the inner circumference of the third air duct 334.

[0068] In some embodiments, the ventilation pipe assembly 3 further includes a first regulating valve 351, a second regulating valve 352 and a third regulating valve 353. The first regulating valve 351 is provided at the air inlet of the first air duct 311, and is used to adjust the air volume entering the first air duct 311. The second regulating valve 352 is provided at the air inlet of the second air duct 312, and is used to adjust the air volume entering the second air duct 312. The third regulating valve 353 is provided at the air inlet of the third air duct 313, and is used to adjust the air volume entering the third air duct 313.

[0069] Specifically, the ventilation pipe assembly 3 further includes a first branch pipe 361, a second branch pipe 362 and a third branch pipe 363. The first branch pipe 361 is arranged at the left end of the first air duct 332, and the central axis of the first branch pipe 361 is orthogonal to the central axis of the first air duct 332. The first branch pipe 361 has a first air inlet 3611, and ventilation is conducted into the first air duct 311 through the first air inlet 3611. The first regulating valve 351 is arranged at the first air inlet 3611, and the air volume entering the first air duct 332 is regulated by regulating the opening of the first air inlet 3611.

[0070] The second branch pipe 362 is disposed at the left end of the second air duct 333, and the central axis of the second branch pipe 362 is orthogonal to the central axis of the second air duct 333. The second branch pipe 362 has a second air inlet 3621, through which ventilation is conducted into the second air duct 312, and the second regulating valve 352 is disposed at the second air inlet 3621, and the air volume entering the second air duct 333 is regulated by regulating the opening of the second air inlet 3621.

[0071] The third branch pipe 363 is disposed at the left end of the third air duct 334, and the central axis of the third branch pipe 363 is orthogonal to the central axis of the third air duct 334. The third branch pipe 363 has a third air inlet 3631, through which ventilation is conducted into the third air duct 313, and the third regulating valve 353 is disposed at the third air inlet 3631, and the air volume entering the third air duct 334 is regulated by regulating the opening of the third air inlet 3631.

[0072] In some embodiments, the ventilation pipe assembly 3 further includes a first guide 371, a second guide 372 and a third guide 373. The first guide 371 is arranged at the first air outlet 321 to adjust the wind direction of the wind entering the combustion chamber 411 from the first air duct 311, the second guide 372 is arranged at the second air outlet 322 to adjust the wind direction of the wind entering the combustion chamber 411 from the second air duct 312, and the third guide 373 is arranged at the third air outlet 323 to adjust the wind direction of the wind entering the combustion chamber 411 from the third air duct 313. Specifically, the arrangement of the guide can effectively improve the turbulent state of the wind when it flows, reduce energy consumption and wind resistance, ensure that the wind flows more smoothly, and thus ensure the stability of the combustion of coal powder in the combustion chamber 411.

[0073] In some embodiments, the combustion assembly 4 includes a reflow tube 41, a reinforcement tube 42 and a jet tube 43. The reflow tube 41 is disposed at one end of the third air duct 313 (eg Figure 3The combustion chamber 411 is formed in the inner cavity of the recirculation tube 41. Specifically, the recirculation tube 41 is an expanded cylindrical shape, and the diameter of the recirculation tube 41 gradually increases from the left end of the recirculation tube 41 to the right end of the recirculation tube 41 along the first direction, so that the cross-sectional area of ​​the combustion chamber 411 gradually increases from the left end of the recirculation tube 41 to the right end of the recirculation tube 41 along the first direction.

[0074] The reinforcement tube 42 is sleeved outside the reflux tube 41 to strengthen the structural strength of the reflux tube 41. Specifically, the reinforcement tube 42 is an axisymmetric body with a narrow right-angled triangle cross section. The reinforcement tube 42 is sleeved on the outer circumference of the reflux tube 41 as a whole, and the inner circumference of the reinforcement tube 42 is matched with the outer circumference of the reflux tube 41.

[0075] Specifically, the reinforcing tube 42 is made of thermal insulation material. On the one hand, it is used to prevent excessive heat from being dissipated from the reflux tube 41 to the outer wall of the main body 1 and causing its temperature to be too high. On the other hand, it can maintain a higher temperature in the reflux tube 41 to promote rapid ignition and stable combustion of coal powder.

[0076] The injection tube 43 is arranged at one end of the main body 1. The injection tube 43 has an injection chamber 431 connected to the chamber 11. The injection chamber 431 is connected to the combustion chamber. The diameter of the injection chamber 431 gradually decreases along the first direction from one end of the injection tube 43 adjacent to the main body 1 to the end of the injection tube 43 away from the main body 1.

[0077] Specifically, the injection cylinder 43 is a constricted cylindrical shape, and the diameter of the injection cylinder 43 gradually decreases along the first direction from the left end of the injection cylinder 43 to the right end of the injection cylinder 43. The inner diameter of the left end of the injection cylinder 43 is larger than the outer diameter of the right end of the reflux cylinder 41, and the left end of the injection cylinder 43 is coaxially sleeved on the right end of the reflux cylinder 41.

[0078] In some embodiments, the body 1 includes a barrel 13 and an extension section 14. The barrel 13 extends along a first direction, the chamber 11 is formed in the barrel 13, and one end of the barrel 13 (such as Figure 3 The right end of the cylinder 13 shown in the figure has a through hole 131, which passes through the right end surface of the cylinder 13 and is connected to the chamber 11. Specifically, the cylinder 13 is made of wear-resistant steel, and the outer peripheral surface of the cylinder 13 is coated with a wear-resistant coating. The arrangement of the cylinder 13, the injection cylinder 43, the reinforcement cylinder 42, the reflow cylinder 41 and the cooling air can effectively avoid the high temperature wear problem of the combustion stabilizing device of the embodiment of the present invention after being installed on the main pulverized coal burner.

[0079] One end of the extension section 14 (such as Figure 3 The left end of the extension section 14 shown in FIG. 1 is disposed at one end of the cylinder 13 and extends along the edge of the through hole 131 in a direction away from the cylinder 13. The other end of the extension section 14 (as shown in FIG. 1 ) is disposed at one end of the cylinder 13 and extends along the edge of the through hole 131 in a direction away from the cylinder 13. Figure 3The right end of the extension section 14 shown in the figure is connected to one end of the injection tube 43. Specifically, the cross-sectional area of ​​the extension section 14 is smaller than the cross-sectional area of ​​the cylinder body 13, and the cross-sectional area of ​​the extension section 14 gradually decreases from one end of the extension section 14 to the other end of the extension section 14 along the first direction.

[0080] Specifically, a plurality of fixing ribs (not shown) spaced apart along the circumferential direction are connected between the outer circumference of the right end of the cylinder 13 and the inner circumference of the extension section 14 to fix the relative position between the right end of the cylinder 13 and the extension section 14 .

[0081] An air distribution channel 15 is formed between the inner circumference of the cylinder 13 and the outer circumference of the third air duct 334, and an air inlet pipe 16 is provided at the left end of the cylinder 13, through which ventilation can be provided to the air distribution channel 15. Specifically, the air inlet pipe 16, the third branch pipe 363, the second branch pipe 362 and the first branch pipe 361 are arranged adjacently and spaced from right to left in the first direction, so as to facilitate subsequent adjustment and maintenance. By constructing a cylinder 13 with a longer length in the first direction, the overall aspect ratio of the combustion stabilizing device is increased, so that the combustion stabilizing device can be easily extended into the main pulverized coal burner of the boiler, which is convenient for the actual arrangement of the combustion stabilizing device of the embodiment of the present invention.

[0082] The right end of the reinforcing tube 42 extends to the right end of the extension section 14 so that a rectifying channel 17 can be formed between the inner circumference of the extension section 14 and the outer circumference of the reinforcing tube 42 . The rectifying channel 17 is annular and connects the air distribution channel 15 and the injection chamber 431 .

[0083] Specifically, when the air flows from left to right in the air distribution channel 15 to the rectifying channel 17, the cross-sectional area of ​​the rectifying channel 17 is instantly reduced, which will increase the along-the-way resistance of the airflow, making the flow distribution of the airflow in the circumferential direction more uniform. At the same time, the jet velocity of the air flow from the nozzle of the rectifying channel 17 is increased, so that this part of the airflow can flow forward along the inner wall of the cylinder 13 while maintaining a high momentum.

[0084] The setting of the rectifying channel 17 can form a low-temperature cooling air film near the inner wall surface of the injection tube 43, thereby preventing the coking and overheating problems of the inner wall of the injection tube 43. Moreover, it has a further gathering effect on the jet flame at the injection chamber 431, thereby enhancing the flame rigidity and reducing the diffusion of the flame, which helps to form a stable "air-powder-wrapped-fire" structure in the pulverized coal burner and effectively avoids the coking and burning problems in the pulverized coal burner.

[0085] The working process of the combustion stabilization device of the embodiment of the present invention is as follows:

[0086] The primary pulverized coal airflow is divided into two streams, which flow into the combustion chamber 411 from the second flow channel 24 and the first flow channel 23 respectively. The pulverized coal airflow flowing into the first flow channel 23 meets the first channel 221, and after being guided by the countercurrent of the first channel 221, forms an equal-diameter annular jet and is ejected at high speed from the coal outlet 227. At this time, the pulverized coal airflow flowing into the second channel 222 will flow into the second channel 222, forming a gradually expanding jet and being ejected at high speed from the coal outlet 227. Then, the two pulverized coal jets ejected from the second channel 222 and the first channel 221 meet and converge into one pulverized coal jet, and then are ejected from right to left into the combustion chamber 411.

[0087] At the same time, the secondary wind (air) enters the first branch pipe 361, the second branch pipe 362 and the third branch pipe 363, and then the air flow flowing into the first branch pipe 361 flows into the first air duct 311 and flows from left to right, and finally flows into the interior of the return tube 41 from the left end of the return tube 41 under the guidance of the first guide member 371. The air flow flowing into the second branch pipe 362 flows into the second air duct 312 and flows from left to right, and finally flows into the interior of the return tube 41 from the left end of the return tube 41 under the guidance of the second guide member 372. The air flow flowing into the third branch pipe 363 flows into the third air duct 313 and flows from left to right, and finally flows into the interior of the return tube 41 from the left end of the return tube 41 under the guidance of the third guide member 373.

[0088] Through the above-mentioned secondary air flow organization structure, a three-layer rotating air flow wrapped from the inside to the outside can be constructed on the left side of the inner part of the reflux cylinder 41, which not only provides oxygen for the coal powder combustion, but also helps to construct a low-pressure area inside the rotating air flow, promotes the suction effect of the high-temperature airflow and the formation of the recirculation zone 12. At the same time, the radial width of the overall swirl secondary air can be reduced by closing or reducing the valve opening on the first branch pipe 361, the second branch pipe 362, and the third branch pipe 363 in turn, thereby achieving the purpose of adjusting the radial width of the high-temperature recirculation zone 12.

[0089] A portion of the remaining air flows from the air inlet pipe 16 into the air distribution channel 15, and flows from left to right into the rectifying channel 17. Under the uniform distribution and acceleration of the airflow in the rectifying channel 17, after being ejected from the rectifying channel 17, it flows at a high speed along the inner wall of the injection tube 43. The high-speed airflow will wrap and carry the flame ejected in the center to flow out, ensuring the good rigidity of the center flame.

[0090] Under the combined action of the above-mentioned pulverized coal airflow, secondary airflow and wall airflow, a high-temperature recirculation zone 12 is formed inside the recirculation tube 41, and a high-temperature flame is generated, which is then accelerated and gathered by the rectifying channel 17 and ejected at high speed from the rectifying channel 17 to form a high-temperature jet flame. When the combustion stabilizing device of the embodiment of the present invention is installed in the main pulverized coal burner of the power plant boiler, the high-temperature flame ejected by the combustion stabilizing device will ignite the main pulverized coal airflow in the main pulverized coal burner located around it.

[0091] The following describes the method for using the combustion stabilization device according to the embodiment of the present invention.

[0092] The embodiment of the present invention discloses a method for using a combustion stabilization device, including:

[0093] Coal powder is introduced into the reflow zone 12 through the coal powder pipe assembly 2, and the type of the coal powder is determined to determine whether it is a low-volatile, difficult-to-combustible coal type or a high-ash, easily combustible coal type.

[0094] When the pulverized coal is of low volatility and difficult to burn type, the amount of pulverized coal in the first flow channel 23 is increased, and the amount of pulverized coal in the second flow channel 24 is reduced. The pulverized coal in the first flow channel 23 and the pulverized coal in the second flow channel 24 are discharged through the coal outlet 22, and the angle a gradually decreases, so that the radial velocity component of the pulverized coal flowing in the recirculation zone 12 is reduced, and the axial velocity component is increased. At the same time, the first air outlet 321 is closed, the opening of the second air outlet 322 is reduced, and the opening of the third air outlet 323 is increased.

[0095] Specifically, when the stable combustion device of the embodiment of the present invention burns low-volatile and difficult-to-burn coal, it is necessary to increase the area of ​​the high-temperature recirculation zone 12 to promote the heating and ignition process of the coal powder airflow. First, the coal powder airflow flow rate flowing into the first flow channel 23 is increased, and the coal powder airflow flow rate flowing into the second flow channel 24 is reduced. At this time, the coal powder airflow flow rate in the first flow channel 23 is increased, and the coal powder airflow flow rate in the second flow channel 24 is reduced. The overall coal powder jet expansion angle formed after the two coal powder airflows converge gradually approaches 0°, which will reduce the radial velocity component of the coal powder jet flowing around, and increase the axial velocity component, so that the overall flow velocity attenuation of the coal powder jet from right to left is slowed down, and after the turn is delayed, it flows from left to right, thereby achieving the purpose of increasing the axial length of the high-temperature recirculation zone 12.

[0096] At the same time, the first regulating valve 351 on the first branch pipe 361 is closed, and the second regulating valve 352 on the second branch pipe 362 is reduced. Since the swirl air volume located inside the swirl secondary air is closed and reduced, the radial size of the swirl secondary air is reduced, and the swirl secondary air is mainly gathered in the near-wall area of ​​the reflux tube 41. Through the secondary air regulation, the width of the high-temperature reflux zone 12 can be increased. Through the above regulation of coal powder and secondary air flow, the area of ​​the high-temperature reflux zone 12 can be increased, promoting the rapid heating, ignition and stable combustion of low-volatile and difficult-to-burn coal.

[0097] When the pulverized coal is a high-ash, flammable type of coal, the amount of pulverized coal in the first flow channel 23 is reduced, and the amount of pulverized coal in the second flow channel 24 is increased. The pulverized coal in the first flow channel 23 and the pulverized coal in the second flow channel 24 are discharged through the coal outlet 22, and the angle a gradually increases, so that the radial velocity component of the pulverized coal flowing in the recirculation zone 12 increases, and the axial velocity component decreases. At the same time, the opening of the first air outlet 321 is increased, the second air outlet 322 is opened, and the third air outlet 323 is closed.

[0098] Specifically, when the stable combustion device of the embodiment of the present invention burns high-volatile and flammable coal, it is necessary to reduce the area of ​​the high-temperature recirculation zone 12. When ensuring the rapid heating and ignition process of the coal powder airflow, it is also necessary to prevent the wall temperature of the recirculation tube 41 from being too high and the adhesion and coking of coal powder particles. First, the coal powder airflow flow rate flowing into the first flow channel 23 is reduced, and the coal powder airflow flow rate flowing into the second flow channel 24 is increased. At this time, the coal powder airflow flow rate in the first flow channel 23 is reduced, and the coal powder airflow flow rate in the second flow channel 24 is increased. The overall coal powder jet expansion angle formed after the two coal powder airflows converge gradually approaches a°, which will increase the radial velocity component of the coal powder jet flowing around, and reduce the axial velocity component, so that the overall flow velocity attenuation of the coal powder jet from right to left is accelerated, and after turning in advance, it flows from left to right, thereby achieving the purpose of reducing the axial length of the high-temperature recirculation zone 12.

[0099] At the same time, the opening of the first regulating valve 351 on the first branch pipe 361 is increased, and the second regulating valve 352 on the second branch pipe 362 is opened. Since the swirl air volume located inside the swirl secondary air increases, the radial size of the swirl secondary air increases, and the swirl secondary air is mainly gathered in the near-wall area of ​​the reflux tube 41. Through the secondary air regulation, the width of the high-temperature reflux zone 12 can be reduced. Through the above regulation of the coal powder and secondary air flow, the area of ​​the high-temperature reflux zone 12 can be reduced, and while ensuring the rapid heating and ignition process of the coal powder air flow, it can prevent the wall temperature of the reflux tube 41 from being too high and the adhesion and coking of coal powder particles.

[0100] The combustion stabilizing device of the embodiment of the present invention is designed to flexibly and effectively adjust the axial length L and radial width D of the recirculation zone 12, thereby flexibly constructing a high-temperature recirculation zone 12 distribution suitable for stable combustion of different types of coal, thereby improving the coal adaptability of the combustion stabilizer.

[0101] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0102] In addition, 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. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0103] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0104] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0105] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0106] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A combustion stabilization device, characterized in that: include: A body (1), the body (1) having a chamber (11), the chamber (11) extending along a first direction, and one end of the chamber (11) having a reflow zone (12); a pulverized coal pipe assembly (2), the pulverized coal pipe assembly (2) being arranged in the chamber (11) and extending along the first direction, one end of the pulverized coal pipe assembly (2) being provided with a coal outlet (227), the coal outlet (227) being in communication with the recirculation zone (12) so as to allow pulverized coal to flow into the recirculation zone (12); a ventilation pipe assembly (3), the ventilation pipe assembly (3) being arranged in the chamber (11) and sleeved outside the pulverized coal pipe assembly (2), one end of the ventilation pipe assembly (3) having an air outlet (32), the air outlet (32) being in communication with the recirculation zone (12) so as to supply air to the recirculation zone (12), and the ventilation pipe assembly (3) being capable of adjusting the air volume entering the recirculation zone (12); A combustion assembly (4), the combustion assembly (4) being arranged at one end of the ventilation pipe assembly (3) and located at one end of the chamber (11), the combustion assembly (4) having a combustion chamber (411), the recirculation zone (12) being formed in the combustion chamber (411), the air outlet (32) being connected to the combustion chamber (411), and the coal outlet (227) being located in the combustion chamber (411).

2. The combustion stabilization device according to claim 1, characterized in that: The pulverized coal pipe assembly (2) comprises: A pulverized coal pipe (21), the pulverized coal pipe (21) extending along the first direction and having a first flow channel (23) and a second flow channel (24) arranged in sequence from the inside to the outside, and both the first flow channel (23) and the second flow channel (24) contain pulverized coal; A coal outlet member (22), the coal outlet member (22) being arranged at one end of the coal powder pipe (21), the coal outlet member (22) having a first channel (221) and a second channel (222), the coal outlet (227) being formed on the coal outlet member (22), the coal outlet (227) being opened along the first direction, the first channel (221) being connected to the first flow channel (23) and the coal outlet (227), the coal powder in the first flow channel (23) being able to flow out from the coal outlet (227) through the first channel (221), the second channel (222) being connected to the second flow channel (24) and the coal outlet (227), the coal powder in the second flow channel (24) being able to flow out from the coal outlet (227) through the second channel (222), and the flow direction of the coal powder flowing out from the first channel (221) and the flow direction of the coal powder flowing out from the second channel (222) being an angle a.

3. The combustion stabilization device according to claim 2, characterized in that: The size of the angle a is adjustable.

4. The combustion stabilization device according to claim 1, characterized in that: The ventilation pipe assembly (3) comprises: a first air duct (311), a second air duct (312) and a third air duct (313), wherein the first air duct (311) is sleeved outside the pulverized coal pipe assembly (2), the first air duct (311), the second air duct (312) and the third air duct (313) are arranged in sequence from the inside to the outside, and the air outlet (32) comprises a first air outlet (321) connecting the first air duct (311) and the combustion chamber (411), a second air outlet (322) connecting the second air duct (312) and the combustion chamber (411), and a third air outlet (323) connecting the third air duct (313) and the combustion chamber (411); A first regulating valve (351), a second regulating valve (352) and a third regulating valve (353), wherein the first regulating valve (351) is arranged at the air inlet of the first air duct (311) and is used to regulate the air volume passing into the first air duct (311); the second regulating valve (352) is arranged at the air inlet of the second air duct (312) and is used to regulate the air volume passing into the second air duct (312); and the third regulating valve (353) is arranged at the air inlet of the third air duct (313) and is used to regulate the air volume passing into the third air duct (313).

5. The combustion stabilization device according to claim 4, characterized in that: The ventilation duct assembly (3) further comprises a first air guide (371), a second air guide (372) and a third air guide (373); the first air guide (371) is arranged at the first air outlet (321) to adjust the wind direction of the wind passing from the first air duct (311) into the combustion chamber (411); the second air guide (372) is arranged at the second air outlet (322) to adjust the wind direction of the wind passing from the second air duct (312) into the combustion chamber (411); the third air guide (373) is arranged at the third air outlet (323) to adjust the wind direction of the wind passing from the third air duct (313) into the combustion chamber (411).

6. The combustion stabilization device according to claim 4, characterized in that: The combustion assembly (4) comprises: A reflux cylinder (41), the reflux cylinder (41) being arranged at one end of the third air duct (313) and located at one end of the chamber (11), and the combustion chamber (411) being formed in the inner cavity of the reflux cylinder (41); A reinforcing cylinder (42), wherein the reinforcing cylinder (42) is sleeved outside the reflux cylinder (41) and is used to enhance the structural strength of the reflux cylinder (41); An injection tube (43), wherein the injection tube (43) is arranged at one end of the main body (1), and the injection tube (43) has an injection cavity (431) connected to the chamber (11), and the injection cavity (431) is connected to the combustion cavity, and the diameter of the injection cavity (431) gradually decreases along the first direction from one end of the injection tube (43) adjacent to the main body (1) to one end of the injection tube (43) away from the main body (1).

7. The combustion stabilization device according to claim 6, characterized in that: The cross-sectional area of ​​the combustion chamber (411) gradually increases along the first direction from one end of the return tube (41) adjacent to the third air duct (313) to one end of the return tube (41) adjacent to the injection tube (43).

8. The combustion stabilization device according to claim 6, characterized in that: The body (1) comprises a barrel (13) and an extension section (14); the barrel (13) extends along the first direction; the chamber (11) is formed in the barrel (13); one end of the barrel (13) has a through hole (131); the through hole (131) is connected to the chamber (11); one end of the extension section (14) is arranged at one end of the barrel (13) and extends along the edge of the through hole (131) in a direction away from the barrel (13); the other end of the extension section (14) is connected to the injection nozzle (11); The reinforcing cylinder (42) is connected to one end of the extension section (14), and an air distribution channel (15) is formed between the inner circumference of the cylinder body (13) and the outer circumference of the third air duct (313). There is wind in the air distribution channel (15). The reinforcing cylinder (42) is adjacent to one end of the injection cylinder (43) and extends to the other end of the extension section (14). A rectifying channel (17) is formed between the inner circumference of the extension section (14) and the outer circumference of the reinforcing cylinder (42). The rectifying channel (17) connects the air distribution channel (15) and the injection chamber (431).

9. The combustion stabilization device according to claim 8, characterized in that: The cross-sectional area of ​​the extension section (14) is smaller than the cross-sectional area of ​​the cylinder (13), and the cross-sectional area of ​​the extension section (14) gradually decreases from one end of the extension section (14) to the other end of the extension section (14) along the first direction.

10. A method for using a combustion stabilization device, characterized in that: include: The pulverized coal is introduced into the reflow zone (12) through the pulverized coal pipe assembly (2), and the type of the pulverized coal is determined to be low-volatile, difficult-to-combustible coal or high-ash, easily combustible coal; When the pulverized coal is a low-volatile, difficult-to-burn type of coal, the amount of pulverized coal in the first flow channel (23) is increased, and the amount of pulverized coal in the second flow channel (24) is reduced. The pulverized coal in the first flow channel (23) and the pulverized coal in the second flow channel (24) are discharged through the coal outlet (22), and the angle a is gradually reduced, so that the radial velocity component of the pulverized coal flowing in the recirculation zone (12) is reduced and the axial velocity component is increased. At the same time, the first air outlet (321) is closed, the opening of the second air outlet (322) is reduced, and the opening of the third air outlet (323) is increased; When the pulverized coal is a high-ash, flammable type of coal, the amount of pulverized coal in the first flow channel (23) is reduced, and the amount of pulverized coal in the second flow channel (24) is increased. The pulverized coal in the first flow channel (23) and the pulverized coal in the second flow channel (24) are discharged through the coal outlet (22), and the angle a gradually increases, so that the radial velocity component of the pulverized coal flowing in the recirculation zone (12) increases, and the axial velocity component decreases. At the same time, the opening of the first air outlet (321) is increased, the second air outlet (322) is opened, and the third air outlet (323) is closed.

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