Stable Combustion Device and Usage Method

Abstract

The present invention discloses a stable combustion device and a using method. The stable combustion device includes a main body, a pulverized coal pipe assembly, a ventilation pipe assembly, and a combustion assembly. The main body has a chamber that extends along a first direction. One end of the chamber has a recirculation zone. The pulverized coal pipe assembly is arranged in the chamber and extends along the first direction. One end of the pulverized coal pipe assembly has a coal outlet, and the coal outlet communicates with the recirculation zone to introduce pulverized coal into the recirculation zone. 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, and the air outlet communicates with the recirculation zone to supply air to the recirculation zone. The combustion assembly is arranged at one end of the ventilation pipe assembly and located at one end of the chamber. The combustion assembly has a combustion chamber, and the recirculation zone 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 of the embodiment of the present invention is applicable to different coal types, has strong adaptability, and stable combustion.

Description

Technical Field

[0001] The present invention relates to the technical field of flame stabilizers, and specifically, to a flame stabilizing device and a usage method thereof. Background Art

[0002] The 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" goal. Under this background, there is an urgent need to develop low-load stable combustion technologies with good operation economy and reliability.

[0003] In related technologies, plasma ignition and other ignition and flame stabilization technologies are usually adopted to achieve the combustion of pulverized coal. However, the plasma ignition technology has a narrow range of applicable coal types, unstable combustion, resulting in incomplete combustion of pulverized coal, and high usage costs, and does not have good operation economy and reliability. Summary of the Invention

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

[0005] To this end, an embodiment of the present invention provides a flame stabilizing device and a usage method thereof.

[0006] The flame stabilizing device according to an embodiment of the present invention includes:

[0007] A main body having a chamber that extends in a first direction, and one end of the chamber has a recirculation zone;

[0008] A pulverized coal pipe assembly disposed in the chamber and extending in the first direction, one end of the pulverized coal pipe assembly has a coal outlet that communicates with the recirculation zone to introduce pulverized coal into the recirculation zone;

[0009] A ventilation pipe assembly disposed in the chamber and sleeved outside the pulverized coal pipe assembly, one end of the ventilation pipe assembly has an air outlet that communicates with the recirculation zone to supply air to the recirculation zone, and the ventilation pipe assembly can adjust the air volume entering the recirculation zone;

[0010] A combustion assembly disposed 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 communicates with the combustion chamber, and the coal outlet is located in the combustion chamber.

[0011] In the stable combustion device according to the embodiment of the present invention, pulverized coal enters the combustion chamber from the coal outlet after passing through the pulverized coal pipe assembly. At the same time, ventilation is carried out in the combustion chamber through the ventilation pipe assembly to assist the combustion of the pulverized coal, increase the temperature of the combustion chamber, thereby strengthening the rapid temperature rise and ignition of the pulverized coal and the stable combustion, and then the pulverized coal introduced into the combustion chamber after ignition is ignited, realizing coal-on-coal ignition, improving the stability of pulverized coal combustion and the combustion efficiency of pulverized coal. The air volume entering the combustion chamber is adjusted through the ventilation pipe assembly to adapt to the combustion of different coal types, improving the coal type adaptability of the stable combustion device, so that the stable combustion device according to the embodiment of the present invention has good operation economy and reliability.

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

[0013] A pulverized coal pipe, which extends along the first direction and has a first flow channel and a second flow channel arranged in sequence from inside to outside, and pulverized coal is present in both the first flow channel and the second flow channel;

[0014] A coal outlet member, which is provided at one end of the pulverized coal pipe. The coal outlet member has a first channel and a second channel, and the coal outlet is formed on the coal outlet member. The coal outlet is opened along the first direction. The first channel communicates the first flow channel and the coal outlet, and the pulverized coal in the first flow channel can flow out from the coal outlet after passing through the first channel. The second channel communicates the second flow channel and the coal outlet, and the pulverized coal in the second flow channel can flow out from the coal outlet through the second channel. There is an included angle a between the flow direction of the pulverized coal flowing out from the first channel and the flow direction of the pulverized coal flowing out from the second channel.

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

[0016] In some embodiments, the ventilation pipe assembly includes:

[0017] A first air duct, a second air duct, and a third air duct. 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 inside to outside. The air outlet includes a first air outlet communicating the first air duct and the combustion chamber, a second air outlet communicating the second air duct and the combustion chamber, and a third air outlet communicating the third air duct and the combustion chamber;

[0018] A first regulating valve, a second regulating valve, and a third regulating valve. The first regulating valve is provided at the air inlet of the first air duct for regulating the air volume introduced into the first air duct. The second regulating valve is provided at the air inlet of the second air duct for regulating the air volume introduced into the second air duct. The third regulating valve is provided at the air inlet of the third air duct for regulating the air volume introduced into the third air duct.

[0019] In some embodiments, the ventilation pipe assembly further includes a first flow guide member, a second flow guide member, and a third flow guide member. The first flow guide member is disposed at the first air outlet to adjust the wind direction of the air flowing from the first air duct into the combustion chamber. The second flow guide member is disposed at the second air outlet to adjust the wind direction of the air flowing from the second air duct into the combustion chamber. The third flow guide member is disposed at the third air outlet to adjust the wind direction of the air flowing from the third air duct into the combustion chamber.

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

[0021] A reflux cylinder, which is disposed at one end of the third air duct and at one end of the chamber, and the combustion chamber is formed inside the reflux cylinder;

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

[0023] An injection cylinder, which is disposed at one end of the main body. The injection cylinder has an injection chamber communicating with the chamber, and the injection chamber communicates with the combustion chamber. The diameter of the injection chamber gradually decreases along the first direction from the end of the injection cylinder adjacent to the main body to the end of the injection cylinder away from the main body.

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

[0025] In some embodiments, the main body includes a cylinder body and an extension section. The cylinder body extends along the first direction, and the chamber is formed inside the cylinder body. One end of the cylinder body has a perforation communicating with the chamber. One end of the extension section is disposed at one end of the cylinder body and extends away from the cylinder body along the edge of the perforation. The other end of the extension section is connected to one end of the injection cylinder. A air distribution channel is formed between the inner peripheral surface of the cylinder body and the outer peripheral surface of the third air duct, and there is air in the air distribution channel. One end of the reinforcing cylinder adjacent to the injection cylinder extends to the other end of the extension section. A rectifying channel is formed between the inner peripheral surface of the extension section and the outer peripheral surface of the reinforcing cylinder, and the rectifying channel communicates the air distribution channel and the injection chamber.

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

[0027] The method of using the stable combustion device according to the embodiment of the present invention includes:

[0028] Inject pulverized coal into the recirculation zone through the pulverized coal pipe assembly, and determine whether the pulverized coal is a low-volatile, difficult-to-burn coal type or a high-ash, easy-to-burn coal type according to the type of pulverized coal;

[0029] When the pulverized coal is a low-volatile, difficult-to-burn coal type, increase the amount of pulverized coal in the first flow channel and reduce the amount of pulverized coal in the second flow channel. The pulverized coal in the first flow channel and the pulverized coal in the second flow channel are discharged through the coal discharging member, and the included angle a gradually decreases, so that the radial velocity component of the pulverized coal flowing in the recirculation zone decreases and the axial velocity component increases. At the same time, close the first air outlet, reduce the opening degree of the second air outlet, and increase the opening degree of the third air outlet;

[0030] When the pulverized coal is a high-ash, easy-to-burn coal type, reduce the amount of pulverized coal in the first flow channel and increase the amount of pulverized coal in the second flow channel. The pulverized coal in the first flow channel and the pulverized coal in the second flow channel are discharged through the coal discharging member, and the included 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, increase the opening degree of the first air outlet, open the second air outlet, and close the third air outlet.

[0031] The method for using the stable combustion device according to the embodiment of the present invention improves the coal type adaptability of the stable combustion device, and the operation process is simple. Description of the Drawings

[0032] Figure 1 is the front view of the stable combustion device according to the embodiment of the present invention.

[0033] Figure 2 is the left view of the stable combustion device according to the embodiment of the present invention.

[0034] Figure 3 is the sectional view of the stable combustion device according to the embodiment of the present invention.

[0035] Figure 4 is Figure 3 the enlarged schematic view of part A in

[0036] Figure 5 is Figure 3 the enlarged schematic view of part B in

[0037] Figure 6 is Figure 3 the enlarged schematic view of part C in

[0038] Figure 7 is Figure 1 the sectional view taken along A-A in

[0039] Figure 8 is Figure 1 the sectional view taken along B-B in

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

[0041] Reference numerals: 1, body; 11, chamber; 12, reflux 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 discharging part; 221, first channel; 222, second channel; 223, protruding part; 224, first guiding part; 225, extension part; 226, second guiding part; 227, coal discharging port; 23, first flow channel; 24, second flow channel; 3, ventilation pipe assembly; 311, first air duct; 312, second air duct; 313, third air duct; 32, air outlet; 321, first air outlet; 322, second air outlet; 323, third air outlet; 331, fixed pipe; 332, first air pipe; 333, second air pipe; 334, third air pipe; 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 member; 372, second guide member; 373, third guide member; 4, combustion assembly; 41, reflux cylinder; 411, combustion chamber; 42, strengthening cylinder; 43, injection cylinder; 431, injection chamber. Detailed implementation manners

[0042] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0043] As Figures 1-9 shown, an embodiment of the present invention provides a stable combustion device and its usage method.

[0044] First, the stable combustion device according to an embodiment of the present invention will be described below.

[0045] The stable combustion device according to an embodiment of the present invention includes 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 (such as the left - right direction as shown) and has a chamber 11. The chamber 11 extends along the first direction. One end of the chamber 11 (such as the right end of the chamber 11 as shown) has a reflux zone 12. As Figure 3 shown, the extension length of the reflux zone 12 in the first direction is L, and the radial radius length of the reflux zone 12 is D. Figure 3 shown, the reflux zone 12 has a reflux zone 12 in the first direction, as Figure 3 shown, the extension length of the reflux zone 12 in the first direction is L, and the radial radius length of the reflux zone 12 is D.

[0046] The pulverized coal pipe assembly 2 is arranged in the chamber 11 and extends along the first direction. One end of the pulverized coal pipe assembly 2 (such asFigure 3 The right end of the pulverized coal pipe assembly 2 as shown extends into the recirculation zone 12 and has a coal outlet 227, and the coal outlet 227 communicates with the recirculation zone 12 to introduce pulverized coal into the recirculation zone 12.

[0047] The ventilation pipe assembly 3 is arranged in the chamber 11 and sleeved outside the pulverized coal pipe assembly 2. One end of the ventilation pipe assembly 3 (such as Figure 3 the right end of the ventilation pipe assembly 3 as shown) extends into the recirculation zone 12 and has an air outlet 32, and the air outlet 32 communicates with the recirculation zone 12 to supply air to the recirculation zone 12, and the ventilation pipe 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 communicates with the combustion chamber 411, and the coal outlet 227 is located in the combustion chamber 411.

[0049] In the stable combustion device of the embodiment of the present invention, pulverized coal enters the combustion chamber 411 from the coal outlet 227 after passing through the pulverized coal pipe assembly 2. At the same time, the combustion chamber 411 is ventilated through the ventilation pipe assembly 3 to assist in burning the pulverized coal, increasing the temperature of the combustion chamber 411, thereby strengthening the rapid temperature rise and ignition of the pulverized coal as well as the stable combustion. Furthermore, the pulverized coal introduced into the combustion chamber 411 after ignition is used to ignite other pulverized coal, improving the stability of pulverized coal combustion and the pulverized coal combustion efficiency. By adjusting the air volume entering the combustion chamber 411 through the ventilation pipe assembly 3 to adapt to the combustion of different coal types, the coal type adaptability of the stable combustion device is improved, so that the stable combustion device of the embodiment of the present invention has good operation economy and reliability.

[0050] In some embodiments, the pulverized coal pipe assembly 2 includes a pulverized coal pipe 21 and a coal outlet member 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 in sequence from inside to outside, and pulverized coal is present in both the first flow channel 23 and the second flow channel 24.

[0051] Specifically, the pulverized coal pipe 21 includes a first pulverized coal pipe 211 and a second pulverized coal pipe 212, and both the first pulverized coal pipe 211 and the second pulverized coal pipe 212 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 inside 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, and the right end of the first pulverized coal pipe 211 extends out of the right end of the second pulverized coal pipe 212. The second flow channel 24 is formed between the inner circumferential surface of the second pulverized coal pipe 212 and the outer circumferential surface 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 discharging member 22 is provided at one end of the pulverized coal pipe 21. The coal discharging member 22 has a first channel 221 and a second channel 222. A coal discharging port 227 is formed on the coal discharging member 22, and the coal discharging port 227 is opened along a first direction. The first channel 221 communicates with the first flow channel 23 and the coal discharging port 227. The pulverized coal in the first flow channel 23 can flow out from the coal discharging port 227 after passing through the first channel 221. The second channel 222 communicates with the second flow channel 24 and the coal discharging port 227. The pulverized coal in the second flow channel 24 can flow out from the coal discharging port 227 through the second channel 222. There is an included angle a between the flowing direction of the pulverized coal flowing out from the first channel 221 and the flowing direction of the pulverized coal flowing out from the second channel 222.

[0053] Specifically, the coal discharging member 22 includes a protruding portion 223, a first guiding portion 224, an extending portion 225, and a second guiding portion 226. The left end of the protruding portion 223 is provided at the right end of the second pulverized coal pipe 212 and is arranged circumferentially around the second pulverized coal pipe 212. The right end of the protruding portion 223 extends along 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 protruding portion 223 is an axisymmetric structure with a central hole, and the inner diameter of the central hole of the protruding portion 223 is the same as the inner diameter of the second pulverized coal pipe 212.

[0054] Specifically, the outer peripheral contour of the protruding portion 223 is frustum-shaped, and the cross-sectional area of the outer peripheral contour of the protruding portion 223 gradually increases from the right end to the left end of the protruding portion 223, so that the outer peripheral surface of the protruding portion 223 is an inclined surface, and the diameter of the outer peripheral contour at the left end of the protruding portion 223 is larger than the outer diameter of the second pulverized coal pipe 212.

[0055] The first guiding portion 224 is an axisymmetric structure with a central hole. The first guiding portion 224 is annular. The inner peripheral surface of the first guiding portion 224 is arranged around the right end of the first pulverized coal pipe 211. The outer peripheral surface of the first guiding portion 224 extends outward, and the outer peripheral surface of the first guiding portion 224 is located outside the protruding portion 223.

[0056] The right end of the extending portion 225 is arranged around the outer peripheral surface of the first guiding portion 224. The left end of the extending portion 225 extends along the first direction toward the protruding portion 223. The extending portion 225 is located outside the protruding portion 223. The inner peripheral surface of the extending portion 225 and the outer peripheral surface of the protruding portion 223 are arranged at intervals. The second channel 222 is formed between the outer peripheral surface of the protruding portion 223 and the inner peripheral surfaces of the first guiding portion 224 and the extending portion 225.

[0057] Specifically, the outer peripheral contour of the extension part 225 is cylindrical, and the inner peripheral contour of the extension part 225 is frustum-shaped. The cross-section of the inner peripheral contour of the extension part 225 gradually increases from the right end to the left end of the extension part 225, so that the inner peripheral surface of the extension part 225 is an inclined surface and is adapted to the outer peripheral surface of the protruding part 223, facilitating the formation of an included angle between the flow direction of the pulverized coal airflow ejected through the second channel 222 and the flow direction of the pulverized coal airflow ejected from the first channel 221.

[0058] Specifically, the second channel 222 can direct the pulverized coal airflow flowing through it to be ejected at a high speed as a conical annular jet. The diameter of the conical pulverized coal jet gradually increases from right to left, and the flow direction of this part of the conical pulverized coal jet injected into the recirculation zone 12 is opposite to the flow direction of the pulverized coal airflow in the second flow channel 24.

[0059] The second guiding part 226 is a cap-shaped axisymmetric structure. The second guiding part 226 is coaxially arranged with the first guiding part 224 and covers the right end of the first guiding part 224. The left end of the second guiding part 226 is connected to the outer peripheral surface of the second pulverized coal pipe 212. The coal outlet 227 is formed at the left end of the second guiding part 226 and is opened along the first direction. The second guiding part 226 has an inner cavity. The protruding part 223, the first guiding part 224, and the extension part 225 are all located in the inner cavity. The first channel 221 is formed between the outer peripheral surfaces of the first guiding part 224 and the extension part 225 and the inner peripheral surface of the second guiding part 226.

[0060] Specifically, the first channel 221 can direct the pulverized coal airflow flowing through it to be ejected at a high speed as an equal-diameter annular jet, and the flow direction of this part of the equal-diameter annular pulverized coal jet injected into the recirculation zone 12 is opposite to the flow direction in the first pulverized coal pipe 211. An included angle a is formed between the central axis of the 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 multiple coal outlets 227, and the multiple coal outlets 227 are arranged at intervals along the circumferential direction of the left end face of the second guiding part 226.

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

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

[0064] Specifically, the value range of the included angle a is: 0 ≤ a < 90°. When no pulverized coal is discharged from the coal outlet 227 in the second flow channel 24 and pulverized coal is discharged from the coal outlet 227 in the first flow channel 23, the pulverized coal jets along the first direction, and at this time the included angle a is 0. When pulverized coal is discharged from the coal outlet 227 in the second flow channel 24 and no pulverized coal is discharged from the coal outlet 227 in the first flow channel 23, the pulverized coal jets along the central axis direction of the outlet of the second channel 222, and at this time 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 pulverized coal pipe assembly 2, and the first air duct 311, the second air duct 312, and the third air duct 313 are arranged in sequence from inside to outside. The air outlet 32 has a first air outlet 321, a second air outlet 322, and a third air outlet 323. The first air outlet 321 communicates with the first air duct 311 and the combustion chamber 411. The second air outlet 322 communicates with the second air duct 312 and the combustion chamber 411. The third air outlet 323 communicates with 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 inside to outside. The fixed pipe 331 is sleeved on the second pulverized coal pipe 212 and is connected to the second pulverized coal pipe 212, and the second pulverized coal 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 peripheral surface of the fixed pipe 331 and the inner peripheral surface of the first air pipe 332, so that the annular air flow flowing out of the first air duct 311 is arranged around the inner peripheral surface of the first air pipe 332. The second air duct 312 is formed between the outer peripheral surface of the first air pipe 332 and the inner peripheral surface of the second air pipe 333, so that the annular air flow flowing out of the second air duct 312 is arranged around the inner peripheral surface of the second air pipe 333. The third air duct 313 is formed between the outer peripheral surface of the second air pipe 333 and the inner peripheral surface of the third air pipe 334, so that the annular air flow flowing out of the third air duct 313 is arranged around the inner peripheral surface of the third air pipe 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 arranged at the air inlet of the first air duct 311 for regulating the air volume introduced into the first air duct 311. The second regulating valve 352 is arranged at the air inlet of the second air duct 312 for regulating the air volume introduced into the second air duct 312. The third regulating valve 353 is arranged at the air inlet of the third air duct 313 for regulating the air volume introduced into 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 provided 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 carried out into the first air duct 311 through the first air inlet 3611. The first regulating valve 351 is provided at the first air inlet 3611, and the air volume entering the first air duct 332 is adjusted by adjusting the opening degree of the first air inlet 3611.

[0070] The second branch pipe 362 is provided 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, and ventilation is carried out into the second air duct 312 through the second air inlet 3621. The second regulating valve 352 is provided at the second air inlet 3621, and the air volume entering the second air duct 333 is adjusted by adjusting the opening degree of the second air inlet 3621.

[0071] The third branch pipe 363 is provided 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, and ventilation is carried out into the third air duct 313 through the third air inlet 3631. The third regulating valve 353 is provided at the third air inlet 3631, and the air volume entering the third air duct 334 is adjusted by adjusting the opening degree of the third air inlet 3631.

[0072] In some embodiments, the ventilation pipe assembly 3 further includes a first deflector 371, a second deflector 372, and a third deflector 373. The first deflector 371 is provided at the first air outlet 321 to adjust the wind direction of the air flowing from the first air duct 311 into the combustion chamber 411. The second deflector 372 is provided at the second air outlet 322 to adjust the wind direction of the air flowing from the second air duct 312 into the combustion chamber 411. The third deflector 373 is provided at the third air outlet 323 to adjust the wind direction of the air flowing from the third air duct 313 into the combustion chamber 411. Specifically, the setting of the deflector can effectively improve the turbulent flow condition when the air flows, reduce the energy consumption and air resistance, ensure that the air flow is smoother, and thus ensure the stability of the combustion of pulverized coal in the combustion chamber 411.

[0073] In some embodiments, the combustion assembly 4 includes a reflux cylinder 41, a reinforcement cylinder 42, and a spray cylinder 43. The reflux cylinder 41 is provided at one end of the third air duct 313 (such as Figure 3at the right end of the third air duct 313 shown) and located at one end of the chamber 11, and a combustion chamber 411 is formed in the inner cavity of the return cylinder 41. Specifically, the return cylinder 41 is a flared cylindrical shape, and the diameter of the return cylinder 41 gradually increases along the first direction from the left end to the right end of the return cylinder 41, so that the cross-sectional area of the combustion chamber 411 gradually increases along the first direction from the left end to the right end of the return cylinder 41.

[0074] The reinforcement cylinder 42 is sleeved outside the return cylinder 41 and is used to enhance the structural strength of the return cylinder 41. Specifically, the reinforcement cylinder 42 is an axisymmetric body with a long and narrow right-angled triangle cross-section. The whole reinforcement cylinder 42 is sleeved on the outer peripheral surface of the return cylinder 41, and the inner peripheral surface of the reinforcement cylinder 42 cooperates with the outer peripheral surface of the return cylinder 41.

[0075] Specifically, the reinforcement cylinder 42 is made of heat-insulating material. On the one hand, it is used to prevent excessive heat from dissipating from the inside of the return cylinder 41 to the outer wall of the main body 1 and making its temperature too high. On the other hand, it can maintain a relatively high temperature inside the return cylinder 41, promoting the rapid ignition and stable combustion of pulverized coal.

[0076] The injection cylinder 43 is arranged at one end of the main body 1. The injection cylinder 43 has an injection chamber 431 communicating with the chamber 11. The injection chamber 431 communicates with the combustion chamber, and the diameter of the injection chamber 431 gradually decreases along the first direction from the end of the injection cylinder 43 adjacent to the main body 1 to the end of the injection cylinder 43 far from the main body 1.

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

[0078] In some embodiments, the main body 1 includes a cylindrical body 13 and an extension section 14. The cylindrical body 13 extends along the first direction, and the chamber 11 is formed inside the cylindrical body 13. One end of the cylindrical body 13 (such as Figure 3 the right end of the cylindrical body 13 shown) has a perforation 131, and the perforation 131 penetrates the right end face of the cylindrical body 13 and communicates with the chamber 11. Specifically, the cylindrical body 13 is processed from wear-resistant steel, and a wear-resistant coating is provided on the outer peripheral surface of the cylindrical body 13. The settings of the cylindrical body 13, the injection cylinder 43, the reinforcement cylinder 42, the return cylinder 41, and the cooling air can effectively avoid the high-temperature wear problem of the stable combustion device in 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) is arranged at one end of the cylindrical body 13 and extends along the edge of the perforation 131 in a direction away from the cylindrical body 13. The other end of the extension section 14 (such as Figure 3The right end of the shown extension section 14 is connected to one end of the injection cylinder 43. Specifically, the cross-sectional area of the extension section 14 is smaller than that 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 in the first direction.

[0080] Specifically, a plurality of fixing ribs (not shown) arranged at intervals in the circumferential direction are connected between the outer circumferential surface of the right end of the cylinder body 13 and the inner circumferential surface of the extension section 14 to fix the relative position between the right end of the cylinder body 13 and the extension section 14.

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

[0082] The right end of the strengthening cylinder 42 extends to the right end of the extension section 14, so that a rectifying channel 17 can be formed between the inner circumferential surface of the extension section 14 and the outer circumferential surface of the strengthening cylinder 42. The rectifying channel 17 is annular, and the rectifying channel 17 communicates with the air distribution channel 15 and the injection cavity 431.

[0083] Specifically, when the air flow flows from left to right in the air distribution channel 15 to the rectifying channel 17, due to the sudden reduction of the cross-sectional area of the rectifying channel 17, the frictional resistance along the flow path of the air flow is increased, making the flow rate distribution of the air flow in the circumferential direction more uniform. At the same time, the jet velocity of the air flow at the outlet of the rectifying channel 17 is increased, so that this part of the air flow can maintain a relatively high momentum and flow forward along the inner wall of the cylinder body 13.

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

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

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

[0087] Meanwhile, the secondary air (air) enters the first branch pipe 361, the second branch pipe 362, and the third branch pipe 363. Then, the air flow entering the first branch pipe 361 flows into the first air duct 311 and flows from left to right. Finally, under the guiding action of the first guide member 371, it flows into the interior of the return cylinder 41 from the left end of the return cylinder 41. The air flow entering the second branch pipe 362 flows into the second air duct 312 and flows from left to right. Finally, under the guiding action of the second guide member 372, it flows into the interior of the return cylinder 41 from the left end of the return cylinder 41. The air flow entering the third branch pipe 363 flows into the third air duct 313 and flows from left to right. Finally, under the guiding action of the third guide member 373, it flows into the interior of the return cylinder 41 from the left end of the return cylinder 41.

[0088] Through the above secondary air flow organizational structure, it is possible to construct three layers of rotating air flows wrapped from the inside to the outside on the left side inside the return cylinder 41. While providing oxygen for pulverized coal combustion, it helps to construct a low-pressure area inside the rotating air flow, promotes the entrainment effect of the high-temperature air flow and the formation of the recirculation zone 12. At the same time, by sequentially closing or reducing the valve openings on the first branch pipe 361, the second branch pipe 362, and the third branch pipe 363, the radial width of the overall swirling secondary air can be reduced, so as to achieve the purpose of adjusting the radial width of the high-temperature recirculation zone 12.

[0089] A part 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 rectification channel 17. After being ejected from the rectification channel 17 under the air flow uniform distribution and acceleration action of the rectification channel 17, it flows at high speed along the inner wall of the injection cylinder 43. This high-speed air flow will wrap and carry the flame ejected from the center, ensuring the good rigidity of the center flame.

[0090] Under the combined action of the above-mentioned pulverized coal air flow, secondary air flow, and wall air flow, a high-temperature recirculation zone 12 is formed inside the recirculation cylinder 41, and a high-temperature flame is generated. Then, through the acceleration and convergence effect of the rectification channel 17, it is ejected at a high speed from the rectification channel 17 to form a high-temperature jet flame. When the stable combustion device of the embodiment of the present invention is installed in the main pulverized coal burner of a power station boiler, the high-temperature flame ejected by the stable combustion device will ignite the main pulverized coal air flow in the main pulverized coal burner around it.

[0091] The following describes the usage method of the stable combustion device of the embodiment of the present invention.

[0092] The embodiment of the present invention discloses a usage method of a stable combustion device, including:

[0093] Pulverized coal is introduced into the recirculation zone 12 through the pulverized coal pipe assembly 2, and it is judged whether the pulverized coal is a low-volatile, difficult-to-burn coal type or a high-ash, easy-to-burn coal type according to the type of the pulverized coal.

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

[0095] Specifically, when the stable combustion device of the embodiment of the present invention burns a low-volatile, difficult-to-burn coal type, it is necessary to increase the area of the high-temperature recirculation zone 12 to promote the heating and ignition process of the pulverized coal air flow. First, increase the flow rate of the pulverized coal air flow flowing into the first flow channel 23, and at the same time decrease the flow rate of the pulverized coal air flow flowing into the second flow channel 24. At this time, the flow rate of the pulverized coal air flow in the first flow channel 23 is increased, and the flow rate of the pulverized coal air flow in the second flow channel 24 is decreased. The expansion angle of the overall pulverized coal jet formed after the two pulverized coal air flows converge gradually approaches 0°, which will reduce the radial velocity component of the pulverized coal jet flowing around, and at the same time increase the axial velocity component, so that the flow velocity attenuation of the overall pulverized coal jet from right to left slows down, and after delaying the turning, 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] Through design, the stable combustion device according to the embodiment of the present invention can flexibly and effectively adjust the axial length L and the radial width D of the recirculation zone 12, so as to flexibly construct the distribution of the high-temperature recirculation zone 12 suitable for stable combustion of different coal types, and improve the coal type adaptability of the flame stabilizer.

[0101] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0102] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0103] In the present invention, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected to", "fixed" and the like should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection or communication with each other; it may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, 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, the first feature being "on" or "under" the second feature may be 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, the first feature being "above", "over" and "on" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "under" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0105] In the present invention, terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection 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 specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0106] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to 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) having 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 in communication with the combustion chamber (411), and the coal outlet (227) being located in the combustion chamber (411); The pulverized coal pipe assembly (2) comprises: A pulverized coal pipe (21), the pulverized coal pipe (21) having a first flow channel (23) and a second flow channel (24); 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 first channel (221) being connected to the first flow channel (23) and the coal outlet (227), the second channel (222) being connected to the second flow channel (24) and the coal outlet (227), the flow direction of the coal powder flowing out of the first channel (221) and the flow direction of the coal powder flowing out of the second channel (222) being an angle a, the size of the angle a being adjustable.

2. The combustion stabilization device according to claim 1, characterized in that: The pulverized coal pipe (21) extends along the first direction, and the first flow channel (23) and the second flow channel (24) are 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; The coal outlet (227) is opened along the first direction, and the coal powder in the first flow channel (23) can flow out of the coal outlet (227) through the first channel (221), and the coal powder in the second flow channel (24) can flow out of the coal outlet (227) through the second channel (222).

3. 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).

4. The combustion stabilization device according to claim 3, 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).

5. The combustion stabilization device according to claim 3, characterized in that: The combustion assembly (4) comprises: A reflux cylinder (41), the reflux cylinder (41) being disposed at one end of the third air duct (313) and located at one end of the chamber (11), the combustion chamber (411) being formed in an inner cavity of the reflux cylinder (41); A reinforcing tube (42), wherein the reinforcing tube (42) is sleeved outside the reflux tube (41) and is used to enhance the structural strength of the reflux tube (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 chamber (411), 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).

6. The combustion stabilization device according to claim 5, 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).

7. The combustion stabilization device according to claim 5, 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).

8. The combustion stabilization device according to claim 7, 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.

9. A method for using the combustion stabilization device according to any one of claims 1 to 8, characterized in that: include: The pulverized coal is introduced into the reflux zone (12) through the pulverized coal pipe assembly (2), 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; When the pulverized coal is a low-volatile, flame-retardant 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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