Multi-stage coal dust burner

Abstract

The present application relates to the technical field of boiler combustion and discloses a multi-stage coal powder burner, which comprises an outer combustion cylinder, an inner combustion cylinder, an adjuster and a combustion stabilizer, the inner combustion cylinder is arranged inside the outer combustion cylinder, a channel is formed between the outer combustion cylinder and the inner combustion cylinder, the adjuster is connected with the outer combustion cylinder, the adjuster is used for guiding mixed gas flow, the mixed gas flow can be divided into a first-stage gas flow flowing through the inner combustion cylinder and a second-stage gas flow flowing through the channel, the adjuster is used for adjusting the flow of the first-stage gas flow and the second-stage gas flow, the combustion stabilizer is connected with the inner combustion cylinder, the combustion stabilizer is provided with a flame spout, the flame spout is arranged in the inner combustion cylinder and is used for spouting a flame to ignite the first-stage gas flow and the second-stage gas flow step by step. The multi-stage coal powder burner of the present application can adapt to different coal types to realize rapid ignition and stable and sufficient combustion.

Description

Technical Field

[0001] This invention belongs to the field of boiler combustion technology, specifically relating to a multi-stage pulverized coal burner. Background Technology

[0002] To address the challenges of pulverized coal ignition, stable combustion, and complete combustion during boiler start-up and low-load operation due to low furnace temperatures, existing technologies include pulverized coal burner systems that use high-concentration pulverized coal to form a stable central flame, igniting the main pulverized coal gas flow for combustion support. However, because the structural dimensions of pulverized coal burner systems are larger than traditional plasma igniters or micro-oil igniters, traditional burners are not compatible with them. Furthermore, ensuring gradual ignition of pulverized coal to reduce ignition difficulty, adapting to different types of pulverized coal, and achieving a reasonable internal pressure drop within the burner are also problems that need to be solved. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of the present invention propose a multi-stage pulverized coal burner that can adapt to different coal types to achieve rapid ignition and stable, complete combustion.

[0004] The multi-stage pulverized coal burner of this invention includes an outer combustion cylinder, an inner combustion cylinder, a cylinder regulator, and a flame stabilizer. The inner combustion cylinder is disposed inside the outer combustion cylinder, and a channel is formed between the outer combustion cylinder and the inner combustion cylinder. The regulator is connected to the outer combustion cylinder and is used to introduce a mixed airflow. The mixed airflow can be split into a primary airflow flowing through the inner combustion cylinder and a secondary airflow flowing through the channel. The regulator is used to adjust the flow rates of the primary airflow and the secondary airflow. The flame stabilizer is connected to the inner combustion cylinder and has a flame nozzle. The flame nozzle is placed inside the inner combustion cylinder and is used to eject flames to ignite the primary airflow and the secondary airflow stage by stage.

[0005] The multi-stage pulverized coal burner of this invention divides the mixed gas flow into a primary flow and a secondary flow, enabling the gradual and sequential ignition of the two flow streams. This reduces the heat required for a single ignition and lowers the difficulty of ignition by using a batch ignition method. Stable combustion is achieved, and unburned combustible gases in the primary flow can continue to burn with the secondary flow, ensuring complete combustion. It can easily ignite pulverized coal and achieve stable combustion under startup and low-load conditions. Furthermore, in this embodiment, the secondary flow in the channel can envelop the primary flow burning within the inner cylinder, achieving air-fire envelopment. This preheating of the secondary flow also controls the combustion process, preventing risks such as high-temperature burnout, ash accumulation, and coking of the burner. Additionally, this embodiment allows for adjustment of the ratio of the primary and secondary flow streams via a regulator, meaning the proportion of the primary flow can be rationally allocated according to the pulverized coal conditions, adapting to various types of pulverized coal and achieving stable and complete combustion.

[0006] In some embodiments, the regulator includes an outer casing and a turbulence-disrupting assembly. The outer casing is in communication with the outer combustion chamber and is used to introduce the mixed airflow and divert it to the channel and the inner combustion chamber. The turbulence-disrupting assembly is disposed within the outer casing and includes at least one of a double cone, a single cone, an annular body, and a swirling fluid. The turbulence-disrupting assembly is used to regulate the flow rates of the primary airflow and the secondary airflow.

[0007] In some embodiments, the regulator further includes a connecting plate, one end of which can be connected to the agitator assembly, and the other end of which can be connected to the housing.

[0008] In some embodiments, the regulator further includes a slide, a slider, a spring, and an operating rod. The slide is disposed on the side wall of the housing and is arranged in a direction parallel to the axis of the housing. The slider is placed in the slide and can move along the slide. The other end of the connecting plate is connected to the slider. The spring is placed in the slide, with one end connected to the slide and the other end connected to the slider. The spring is used to reset the slider toward one end of the slide. The operating rod is connected to the slider and is used to operate the slider and move the turbulence assembly together.

[0009] In some embodiments, the double cone has a smaller diameter at both ends and a larger diameter in the middle. The double cone is connected to one end of the connecting plate. The axis of the double cone coincides with the axis of the outer shell. One end of the double cone faces the inner combustion cylinder and can be placed inside the inner combustion cylinder.

[0010] In some embodiments, the single cone is a cone or a frustum, one end of the single cone is connected to the connecting plate, the axis of the single cone coincides with the axis of the outer shell, the small end of the single cone faces the mixed airflow, and the portion of the mixed airflow entering the channel increases after being turbulent by the single cone.

[0011] In some embodiments, the swirling fluid includes a central cylinder connected to one end of the connecting plate, the axis of the central cylinder coincides with the axis of the outer shell, and turbulence fan blades are provided on the outer edge surface of the central cylinder. After being turbulent by the swirling fluid, the mixed airflow can rotate into the channel or the inner combustion cylinder, and the portion entering the channel increases.

[0012] In some embodiments, the outer edge of the annulus is connected to the side wall of the outer shell or one end of the connecting plate, the axis of the annulus coincides with the axis of the outer shell, and the portion of the mixed airflow entering the inner combustion cylinder after being turbulent by the annulus increases.

[0013] In some embodiments, the outer combustion cylinder includes a first bend section, a first tapered section, and a first straight section. The diameter of the first bend section is larger than the diameter of the first straight section. One end of the first bend section is connected to the first straight section via the first tapered section. The mixed airflow is introduced by the first bend section and flows sequentially through the first bend section and the first tapered section before being discharged from the first straight section.

[0014] In some embodiments, the internal combustion cylinder includes a second bend section, a second tapered section, a second straight section, a third tapered section, and a third straight section. The diameter of the second bend section is larger than the diameter of the second straight section and the diameter of the third straight section. One end of the second bend section is connected to the second straight section via the second tapered section, and the other end of the second bend section is connected to the third tapered section and the third straight section. The shapes of the second bend section and the first bend section, the second tapered section and the first tapered section, and the second straight section and the first straight section are adapted to each other.

[0015] In some embodiments, the internal combustion cylinder further includes a fourth tapered section, which is a conical cylinder with one end larger than the other. Either end of the fourth tapered section is connected to the third straight section. The primary airflow enters through the fourth tapered section and flows sequentially through the third straight section, the third tapered section, the second bend section, and the second tapered section before exiting through the second straight section.

[0016] In some embodiments, the diameter of the third straight section is D. B1 The diameter of the first bend is D. B2 The diameter at the maximum diameter of the bicone is D. T The vertical distance from the small end of the bicone to the center of the bicone is H, where D B1 / D B2 =0.3-0.6, D T ≤D B2 H>D T .

[0017] In some embodiments, the distance from the center of the outer shell to the connection point of the first bend is L1, and L1 is selected according to the type of pulverized coal.

[0018] In some embodiments, the velocity of the primary airflow is greater than or equal to 18 m / s.

[0019] The multi-stage pulverized coal burner of this invention can achieve different airflow distribution modes, such as rich internal and lean external, or rich external and lean internal, through various types of regulators. The proportion of the primary airflow is adjusted from high to low according to the difficulty of igniting the pulverized coal, ultimately achieving easy ignition of various types of pulverized coal and maintaining sufficient and stable combustion, enhancing pulverized coal ignition, and simultaneously reducing nitrogen oxides. Furthermore, through the cooperation of structures such as chutes and connecting plates with blunt bodies, online real-time adjustment can be achieved. Attached Figure Description

[0020] Figure 1 This is a three-dimensional schematic diagram of the entire invention.

[0021] Figure 2 This is a front cross-sectional view of the present invention.

[0022] Figure 3 This is a schematic diagram of different types of internal combustion cylinders in this invention.

[0023] Figure 4 This is a schematic diagram of the airflow of the present invention.

[0024] Figure 5 This is a three-dimensional schematic diagram of the annulus in this invention.

[0025] Figure 6 This is a front cross-sectional view of the annulus in this invention.

[0026] Figure 7 This is a three-dimensional schematic diagram of the swirling fluid in this invention.

[0027] Figure 8 This is a front cross-sectional view of the swirling fluid in this invention.

[0028] Figure 9 This is a front sectional view of the cone in this invention.

[0029] Figure 10 This is a three-dimensional schematic diagram of the blunt body in this invention.

[0030] Figure 11 This is a three-dimensional schematic diagram of the interaction between the blunt body and the groove, connecting plate, slider, etc. in this invention.

[0031] Figure 12 These are schematic diagrams of frontal cross-sections of different types of blunt bodies.

[0032] Figure 13 These are schematic diagrams showing the dimensions of different types of blunt bodies.

[0033] Figure label:

[0034] 1. External combustion chamber; 101. First bend section; 102. First tapering section; 103. First straight section;

[0035] 2. Inner combustion cylinder; 201. Second bend section; 202. Second tapering section; 203. Second straight section; 204. Third tapering section; 205. Third straight section; 206. Fourth tapering section;

[0036] 3. Flame stabilizer; 301. Flame nozzle;

[0037] 4. Regulator; 41. Housing; 40. Baffle assembly; 401. Double cone; 402. Single cone; 403. Circular ring; 404. Swirl; 42. Slide groove; 43. Connecting plate; 44. Slider; 45. Spring; 46. Operating lever;

[0038] 6. Mixed airflow;

[0039] 7. Primary airflow;

[0040] 8. Secondary airflow;

[0041] 9. Passage. Detailed Implementation

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

[0043] like Figures 1-13 As shown, the multi-stage pulverized coal burner of this embodiment of the invention includes an outer combustion chamber 1, an inner combustion chamber 2, a flame stabilizer 3, and a regulator 4.

[0044] The outer combustion chamber 1 is used to introduce the mixed airflow 6. The inner combustion chamber 2 is located inside the outer combustion chamber 1. There is a channel 9 between the outer combustion chamber 1 and the inner combustion chamber 2. The inner combustion chamber 2 is used to split the mixed airflow 6 into the primary airflow 7 flowing through the inner combustion chamber 2 and the secondary airflow 8 flowing through the channel 9. The flame stabilizer 3 is connected to the inner combustion chamber 2. The flame stabilizer 3 has a flame nozzle 301. The flame nozzle 301 is placed inside the inner combustion chamber 2 and is used to spray flames to ignite the primary airflow 7 and the secondary airflow 8 respectively. The regulator 4 is located between the outer combustion chamber 1 and the inner combustion chamber 2 and is used to regulate the flow rate of the primary airflow 7 and the secondary airflow 8.

[0045] The multi-stage pulverized coal burner of this invention divides the mixed gas flow 6 into a primary gas flow 7 and a secondary gas flow 8, enabling the two gas flows to be ignited sequentially. This reduces the heat required for a single ignition and lowers the difficulty of ignition by igniting in batches, achieving stable combustion. Unburned combustible gases in the gas flow can continue to burn with the secondary gas flow 8, achieving complete combustion. It can be easily ignited and achieve fully stable combustion under startup and low-load conditions. Furthermore, in this embodiment, the secondary gas flow 8 in the annular channel 9 can envelop the primary gas flow 7 burning in the inner cylinder, achieving air-fire envelopment. This preheating of the secondary gas flow 8 also controls the combustion process, preventing risks such as high-temperature burnout, ash accumulation, and coking of the burner. Additionally, this embodiment allows for adjustment of the ratio of the primary gas flow 7 and the secondary gas flow 8 via the regulator 4. This means that the proportion of the primary gas flow 7 can be rationally allocated according to the pulverized coal conditions, adapting to various types of pulverized coal and achieving ignition and fully stable combustion.

[0046] Specifically, for coal types that are easy to ignite (ignition temperature ≤ 800℃), the flow rate of the primary airflow 7 is reduced by regulator 4 to prevent high-temperature coking and burn-off. Conversely, for coal types that are difficult to ignite (ignition temperature > 800℃), the flow rate of the primary airflow 7 is increased by regulator 4 to increase the volatile matter concentration per unit volume, which is beneficial for ignition and stable combustion of pulverized coal. This solves the problems of difficult ignition, stable combustion, and complete combustion of pulverized coal, as well as the difficulty of stable combustion at low boiler loads.

[0047] The specific arrangement and operating principle of the multi-stage pulverized coal burner according to an embodiment of the present invention are described below.

[0048] like Figures 1-13 As shown, the multi-stage pulverized coal burner of this embodiment of the invention includes an outer combustion chamber 1, an inner combustion chamber 2, a flame stabilizer 3, and a regulator 4.

[0049] The inner combustion chamber 2 is located inside the outer combustion chamber 1, and a channel 9 is formed between the outer combustion chamber 1 and the inner combustion chamber 2. The regulator 4 is connected to the outer combustion chamber 1 and is used to introduce the mixed airflow 6. The mixed airflow 6 can be split into the primary airflow 7 flowing through the inner combustion chamber 2 and the secondary airflow 8 flowing through the channel 9. The regulator 4 is used to adjust the flow rate of the primary airflow 7 and the secondary airflow 8. The flame stabilizer 3 is connected to the inner combustion chamber 2 and has a flame nozzle 301. The flame nozzle 301 is placed inside the inner combustion chamber 2 and is used to spray flames to ignite the primary airflow 7 and the secondary airflow 8 respectively.

[0050] The multi-stage pulverized coal burner of this invention divides the mixed gas flow 6 into a primary gas flow 7 and a secondary gas flow 8, enabling the two gas flows to be ignited sequentially. This reduces the heat required for a single ignition and lowers the difficulty of ignition by igniting in batches, achieving stable combustion. Unburned combustible gases in the gas flow can continue to burn with the secondary gas flow 8, achieving complete combustion. It can be easily ignited and achieve fully stable combustion under startup and low-load conditions. Furthermore, in this embodiment, the secondary gas flow 8 in the annular channel 9 can envelop the primary gas flow 7 burning in the inner cylinder, achieving air-fire envelopment. This preheating of the secondary gas flow 8 also controls the combustion process, preventing risks such as high-temperature burnout, ash accumulation, and coking of the burner. Additionally, this embodiment allows for adjustment of the ratio of the primary gas flow 7 and the secondary gas flow 8 via the regulator 4. This means that the proportion of the primary gas flow 7 can be rationally allocated according to the pulverized coal conditions, adapting to various types of pulverized coal and achieving ignition and fully stable combustion.

[0051] Specifically, for coal types that are easy to ignite (ignition temperature ≤ 800℃), the flow rate of the primary airflow 7 is reduced by regulator 4 to prevent high-temperature coking and burn-off. Conversely, for coal types that are difficult to ignite (ignition temperature > 800℃), the flow rate of the primary airflow 7 is increased by regulator 4, increasing the volatile matter concentration per unit volume, which is beneficial for ignition and stable combustion of pulverized coal. This solves the problems of difficult ignition, stable combustion, and complete combustion of pulverized coal, as well as the difficulty of stable combustion at low boiler loads.

[0052] The specific arrangement and operating principle of the multi-stage pulverized coal burner according to an embodiment of the present invention are described below.

[0053] In this embodiment of the multi-stage pulverized coal burner, the regulator 4 is connected to the pulverized coal supply components of the power plant, such as a mill or coal bunker. The pulverized coal output from the mill or coal bunker is directly transported with the hot primary air through the primary air duct to the outer combustion chamber 1 of the boiler to form a mixed airflow 6. The pulverized coal supply to the burner 3 is independent, or it is enriched from the primary air duct by a pulverized coal enrichment and conveying device before being transported to the burner 3. The pulverized coal flowing through the burner 3 is ignited by the ignition device inside the burner 3 and kept burning continuously. Subsequently, the mixed airflow 6 enters the outer combustion chamber 1 and is split into a primary airflow 7 and a secondary airflow 8. The nozzle 301 of the burner 3 can eject a flame, which is directly aimed at the primary airflow 7, thus igniting the primary airflow 7. The ignited primary airflow 7 continues to be transported and mixed with the secondary airflow 8, igniting the secondary airflow 8. This achieves a gradual ignition effect. By igniting in batches, the heat required for a single ignition is reduced. Furthermore, unburned combustible gases in the mixed airflow 6 can mix with oxygen in the secondary airflow 8 for secondary combustion, achieving complete combustion. Further, the proportion of the primary airflow 7 can be adjusted from high to low according to the difficulty of igniting the pulverized coal, and detailed parameters such as the proportion of the primary airflow 7 can be designed based on actual tests and software simulations. Ultimately, this achieves easy ignition of various types of pulverized coal, maintains sufficient and stable combustion, enhances pulverized coal ignition, and also reduces nitrogen oxide emissions.

[0054] In some embodiments, the regulator 4 includes an outer shell 41 and a turbulence assembly 40. The outer shell 41 is in communication with the outer combustion chamber 1 and is used to introduce the mixed airflow 6 and divert it to the channel 9 and the inner combustion chamber 2. The turbulence assembly 40 is disposed inside the outer shell 41 and includes at least one of a double cone 401, a single cone 402, an annular body 403, and a swirling body 404. The turbulence assembly 40 is used to regulate the flow rates of the primary airflow 7 and the secondary airflow 8.

[0055] The multi-stage pulverized coal burner regulator 4 of this invention includes an outer shell 41 and a turbulence-inducing component 40. The outer shell 41 allows for easy connection to a power plant's grinding mill or coal bunker, facilitating the entry of the mixed airflow 6 into the outer combustion chamber 1. Simultaneously, the turbulence-inducing component 40 is disposed within the outer shell 41. When a different type of outer shell 41 needs to be replaced, it can be replaced directly without disassembling other components, achieving rapid replacement. The turbulence-inducing component 40 can take various forms, and the specific type of regulator 4 can be selected according to the type of pulverized coal to achieve a primary airflow 7 (inner airflow) and a secondary airflow 8 (outer airflow). Adjustments to the regulator 4 can achieve various types such as inner-rich and outer-lean, outer-rich and inner-lean, or uniform inner and outer flow.

[0056] In some embodiments, the regulator 4 further includes a connecting plate 43, one end of which can be connected to the turbulence assembly 40, and the other end of which can be connected to the housing 41.

[0057] Specifically, when the aerodynamic component 40 is any one of a double cone 401, a single cone 402, or a swirling flow 404, in order to achieve installation and avoid the aerodynamic component 40 with the above structure completely blocking the interior of the outer casing 41, a connecting plate 43 can be provided between the outer casing 41 and the aerodynamic component 40 for installation. When the aerodynamic component 40 is a ring 403, the outer edge of the ring 403 can be directly fixed to the outer casing 41 without the need for the connecting plate 43.

[0058] Furthermore, the specific form of the flow-dispersing component 40 can be more varied, such as a baffle, cylinder, square, etc., selected as needed to achieve different distribution ratios and flow rates of the primary airflow 7 and the secondary airflow 8 after the airflow is disturbed. This allows for the use of different coal types.

[0059] In some embodiments, the regulator 4 further includes a slide 42, a slider 44, a spring 45, and an operating rod 46. The slide 42 is disposed on the side wall of the housing 41 and is arranged in a direction parallel to the axis of the housing 41. The slider 44 is placed in the slide 42 and can move along the slide 42. The other end of the connecting plate 43 is connected to the slider 44. The spring 45 is placed in the slide 42, with one end of the spring 45 connected to the slide 42 and the other end of the spring 45 connected to the slider 44. The spring 45 is used to reset the slider 44 toward one end of the slide 42. The operating rod 46 is connected to the slider 44 and is used to operate the slider 44 and drive the turbulence assembly 40 to move together.

[0060] As attached Figure 11 As shown, in the multi-stage pulverized coal burner of this embodiment of the invention, some of the turbulence components 40 can be installed in a movable manner to achieve online adjustment of the position of the turbulence components 40, thereby changing the flow path of the airflow and further achieving the adjustment of the ratio of ·7 and ·8.

[0061] Taking the double cone 401 as an example, a groove 42 is provided on the inner wall of the outer shell 41, and a slider 44 placed in the groove 42 is provided on the connecting plate 43. The two sides of the double cone 401 are connected to the connecting plate 43. Through the above structure, the movement of the double cone 401 can be realized. See Appendix Figure 11-13 As shown, when the double cone 401 is in place, the distance between the double cone 401 and the inner combustion cylinder 2 changes, thus changing the area of ​​the double cone 401 blocking the inner combustion cylinder 2. This changes the flow area of ​​the inner combustion cylinder 2, enabling real-time adjustment of the ratio of the primary airflow 7 and the secondary airflow 8. In other words, through this example, the regulator 4 can perform real-time online adjustment by moving the double cone 401 to adapt to different coal types.

[0062] In addition, in this embodiment, a spring 45 and an operating lever 46 are also provided. The lower end of the operating lever 46 is placed on the outside, which can be easily adjusted manually from the outside or electrically adjusted in conjunction with a motor. In addition, the spring 45 can also be used to keep the double cone 401 close to or far away from the inner combustion cylinder 2 in the initial state, and to make online adjustment when needed.

[0063] In some specific embodiments, a baffle is provided between the connecting plate 43 and the slider 44. The baffle is designed along the inner wall surface of the outer shell 41 and can block the slider 44, thereby ensuring the integrity of the inner wall surface of the outer shell 41 and preventing the mixed airflow 6 inside the outer shell 41 from flowing to the outside of the outer shell 41.

[0064] In some embodiments, the double cone 401 has a smaller diameter at both ends and a larger diameter in the middle. The double cone 401 is connected to one end of the connecting plate 43. The axis of the double cone 401 coincides with the axis of the outer shell 41. One end of the double cone 401 faces the inner combustion cylinder 2 and can be placed inside the inner combustion cylinder 2.

[0065] As attached Figure 10 and attached Figure 12 As shown, the multi-stage pulverized coal burner double cone 401 of this embodiment is specifically a double cone, with the large ends of the two cones connected to each other, forming a shape that is small at both ends and large in the middle. After the mixed gas flow 6 flows through the double cone 401, because the double cone 401 has a shape with a small diameter at both ends and a large diameter in the middle, the flow path of the mixed gas flow 6 is blocked, and the flow rate into the inner combustion cylinder 2 or the channel 9 will also change.

[0066] When the double cone 401 is fixedly installed, that is, when the double cone 401 is directly connected to the side wall of the outer casing 41 via the connecting plate 43, the shape and installation parameters of the double cone 401, such as the maximum diameter of the double cone 401 and the length of the double cone 401 along the axial direction, can be designed to achieve different ratios of primary airflow 7 and secondary airflow 8. In practice, multiple double cones 401 with different shapes can be designed and replaced to adapt to different types of pulverized coal.

[0067] When the double cone 401 is installed in a movable manner, that is, the double cone 401 is installed through the slide groove 42, connecting plate 43, slider 44, spring 45, and operating rod 46. With the help of components such as electric telescopic rod or cylinder to control the operating rod 46, the double cone 401 can be adjusted online and realize the function of real-time adjustment.

[0068] In some embodiments, the single cone 402 is a cone or a frustum. The single cone 402 is connected to one end of the connecting plate 43. The axis of the single cone 402 coincides with the axis of the outer shell 41. The small end of the single cone 402 faces the mixed airflow 6. The portion of the mixed airflow 6 entering the channel 9 increases after being turbulent by the single cone 402.

[0069] As attached Figure 9 As shown, in this embodiment of the multi-stage pulverized coal burner, the conical surface of the single cone 402 causes most of the mixed airflow 6 to enter the channel 9 after passing through the single cone 402, reducing the proportion of the primary airflow 7 and achieving a richer external and leaner internal configuration. Furthermore, the single cone can also be installed in a similar fixed or movable manner as the double cone 401. Details are omitted here, to achieve adjustment of the flow rate of different primary airflows 7.

[0070] In some embodiments, the swirling fluid 404 includes a central cylinder connected to one end of the connecting plate 43. The axis of the central cylinder coincides with the axis of the outer shell 41. Turbulence fan blades are provided on the outer edge surface of the central cylinder. After being turbulent by the swirling fluid 404, the mixed airflow 6 can rotate into the channel 9 or the inner combustion cylinder 2, and the portion entering the channel 9 increases.

[0071] As attached Figure 7-8 As shown, in the multi-stage pulverized coal burner of this embodiment, the central cylinder of the swirling fluid 404 obstructs the smooth entry of the mixed airflow 6 into the inner combustion chamber 2, thus achieving a richer outer layer and a leaner inner layer. Furthermore, through the turbulence fan blades, the airflow entering the inner combustion chamber 2 or channel 9 is rotated, preventing pulverized coal residue from remaining on the pipe wall and improving combustion efficiency. Additionally, the swirling fluid 404 can also be installed in a similar fixed or movable manner as the double cone 401. Details are omitted here, to achieve adjustment of the flow rate of different stage airflows 7.

[0072] In some embodiments, the outer edge of the annular body 403 is connected to the side wall of the outer shell 41 or one end of the connecting plate 43, and the axis of the annular body coincides with the axis of the outer shell 41, so that the portion of the mixed airflow 6 entering the inner combustion cylinder 2 after being turbulent by the annular body 403 is increased.

[0073] As attached Figure 5-6As shown, in the multi-stage pulverized coal burner of this embodiment, a circular ring 403 is provided. The circular ring 403 blocks most of the mixed airflow 6 from entering the channel 9, thereby achieving a richer internal and leaner external configuration. Furthermore, by designing different sizes of the central hole of the circular ring 403, different degrees of richness and leanness can be adjusted to broaden its adaptability to different coal types. The outer edge of the circular ring 403 can be directly fixed to the side wall of the outer shell 41 without the need for a connecting plate 43. When the circular ring 403 needs to be moved, a similar installation method to the double cone 401 can be used, which will not be elaborated further, to adjust the flow rate of different stage airflows 7.

[0074] In some embodiments, the outer combustion cylinder 1 includes a first bend section 101, a first tapering section 102, and a first straight section 103, wherein the diameter of the first bend section 101 is larger than the diameter of the first straight section 103, one end of the first bend section 101 is connected to the first straight section 103 via the first tapering section 102, and the mixed airflow 6 is introduced through the first bend section 101 and flows sequentially through the first bend section 101 and the first tapering section 102 before being discharged from the first straight section 103.

[0075] The internal combustion cylinder 2 includes a second bend section 201, a second tapered section 202, a second straight section 203, a third tapered section 204, and a third straight section 205. The diameter of the second bend section 201 is larger than the diameter of the second straight section 203 and the diameter of the third straight section 205. One end of the second bend section 201 is connected to the second straight section 203 via the second tapered section 202, and the other end of the second bend section 201 is connected to the third tapered section 204 and the third straight section 205. The shapes of the second bend section 201 and the first bend section 101, the second tapered section 202 and the first tapered section 102, and the second straight section 203 and the first straight section 103 are adapted to each other.

[0076] As attached Figure 2 and 3As shown, in the multi-stage pulverized coal burner of this embodiment, the inner combustion cylinder 2 and the outer combustion cylinder 1 are mutually adapted, with the inner combustion cylinder 2 nested inside the outer combustion cylinder 1. The channel 9 is formed by the gap between the inner wall surface of the outer combustion cylinder 1 and the outer wall surface of the inner combustion cylinder 2. The axis of the inner combustion cylinder 2 coincides with the axis of the outer combustion cylinder 1, ensuring that the channel 9 is annular, so that the secondary airflow 8 can flow uniformly and stably along the channel 9. In addition, the inlet of the outer combustion cylinder 1 and the inlet of the inner combustion cylinder 2 can be flush. In this embodiment, due to the design of the third straight cylinder section 205, a flared section is formed at the inlet of the channel 9, which is conducive to the smooth entry of the secondary airflow 8 into the channel 9. Near the outlet of channel 9, at the junction of the first tapering section 102 and the second tapering section 202, the cross-section of channel 9 will shrink, thus increasing the concentration of primary airflow 7 and secondary airflow 8. According to Bernoulli's principle, the flow velocity of primary airflow 7 and secondary airflow 8 will increase. The increase in coal powder concentration and flow velocity facilitates ignition, reduces the difficulty of ignition, and increases the intensity of combustion.

[0077] In some embodiments, the internal combustion cylinder 2 further includes a fourth tapered section 206, which is a conical cylinder with one end larger than the other. Either end of the fourth tapered section 206 is connected to the third straight section 205. The primary airflow 7 enters through the fourth tapered section 206 and flows sequentially through the third straight section 205, the third tapered section 204, the second bend section 201, and the second tapered section 202 before exiting through the second straight section 203.

[0078] See appendix Figure 3 In sections 3.a and 3.b, the fourth tapering section 206 is a conical cylinder, i.e., one end is larger than the other. Through the design of different installation postures of the fourth tapering section 206, the flow ratio of the primary airflow 7 and the secondary airflow 8 can be adjusted. It can further cooperate with the regulator 4 to realize the adjustment of the flow of the primary airflow 7 and the secondary airflow 8, so as to adapt to different coal types.

[0079] In some embodiments, the distance from the center of the outer shell 41 to the connection point of the first bend section 101 is L1, and L1 is selected according to the type of pulverized coal. By pre-setting outer shells 41 of different lengths L1, different types of turbulence components 40 can be quickly replaced during use by changing the outer shell 41. In addition, when L1 is increased, the flow rate of the primary airflow 7 entering the inner combustion chamber 2 increases to accommodate coal types with difficult pulverized coal ignition. When the distance L1 is decreased, the double cone 401 partially blocks the inlet of the inner combustion chamber 2, increasing the inlet pressure of the inner combustion chamber 2, resulting in a reduction in the amount of air and pulverized coal entering the inner combustion chamber 2's primary airflow 7 to accommodate coal types with easy pulverized coal ignition.

[0080] In some embodiments, the diameter of the third straight section 205 is D. B1The diameter of the outer casing 41 and the diameter of the first bend section 101 are both D. B2 D B1 / D B2 =0.3-0.6. This achieves a balance between the cross-sectional area of ​​channel 9 and the cross-sectional area of ​​the inner combustion cylinder 2. The diameter at the maximum diameter of the double cone 401 is set to D. T D T <D B2 This ensures that the mixed airflow 6 can pass smoothly through the double cone 401, preventing the double cone 401 from completely blocking the outer shell 41. The vertical distance from the small end of the double cone 401 to the center of the double cone 401 is H. When H > D T That is, the entire double cone 401 becomes more elongated, increasing the proportion of pulverized coal entering channel 9. When H≤D T That is, the entire double cone 401 is wider, and the proportion of pulverized coal entering the channel 9 is reduced.

[0081] In some embodiments, the velocity of the primary airflow 7 is greater than or equal to 18 m / s. This serves two purposes: firstly, to prevent pulverized coal from depositing in the inner combustion chamber 2; and secondly, by increasing the velocity of the primary airflow 7, to reduce the residence time of pulverized coal in the inner combustion chamber 2, thereby reducing the risk of ash accumulation, coking, and burn-out in the burner.

[0082] See appendix Figure 13 For sections 13.a and 13.b, to ensure that the velocity of the first-order airflow 7 is greater than 18 m / s, the specific structural dimensional requirements for the bicone 401 are as follows:

[0083]

[0084] Wherein, the velocity of the mixed airflow 6 is V0, in such a case... Figure 13 Under the structure shown in 13.b (i.e., without the fourth tapering section 206), the adjustment range is relatively narrow due to the limitation of the minimum wind speed of the pulverized coal airflow. To increase the adjustment range, it is preferable to adopt a structure as shown in 13.b. Figure 13 The structure shown in 13.a (i.e., including a fourth tapered section 206 with its small end connected to the third straight section 205, and its large end facing the double cone 401). In 13.a, the diameter of the large end of the fourth tapered section 206 is D. B10 The projection length of the fourth tapering segment 206 along its own axis is L2. For example... Figure 13 The structure shown in 13.a has the following dimensional requirements:

[0085] (1) This ensures that as the double cone 401 approaches the fourth tapering section 206, the area at the entrance of the fourth tapering section 206 gradually decreases.

[0086] (2) Ensure that the velocity of the primary airflow 7 is greater than or equal to 18 m / s to prevent coal dust deposition.

[0087] Through the structural design in this embodiment and the expression for the flow velocity of the primary airflow 7, the specific structural parameters can be optimized through the above calculations or software simulations to meet the design requirements of the primary airflow 7 flow velocity and adapt to different types of pulverized coal.

[0088] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0089] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0090] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0091] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0092] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0093] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A multi-stage pulverized coal burner, characterized in that, include: External combustion chamber (1); An inner combustion cylinder (2) is located inside the outer combustion cylinder (1), and a channel (9) is formed between the outer combustion cylinder (1) and the inner combustion cylinder (2). Regulator (4), the regulator (4) is connected to the outer combustion cylinder (1), the regulator is used to introduce mixed airflow (6), the mixed airflow (6) can be split into primary airflow (7) flowing through the inner combustion cylinder (2) and secondary airflow (8) flowing through the channel (9), the regulator (4) is used to adjust the flow rate of the primary airflow (7) and the secondary airflow (8); A flame stabilizer (3) is connected to the inner combustion cylinder (2). The flame stabilizer (3) has a flame nozzle (301). The flame nozzle (301) is placed inside the inner combustion cylinder (2) and is used to spray flames to ignite the primary airflow (7) and the secondary airflow (8) step by step. The regulator (4) includes an outer shell (41), a turbulence assembly (40), a connecting plate (43), a slide (42), a slider (44), a spring (45), and an operating rod (46). The outer shell (41) is connected to the outer combustion chamber (1) and is used to introduce the mixed airflow (6) and divert it to the channel (9) and the inner combustion chamber (2). The turbulence assembly (40) is located inside the outer shell (41) and includes at least one of a double cone (401), a single cone (402), an annular body (403), and a swirling fluid (404). The turbulence assembly (40) is used to regulate the flow rates of the primary airflow (7) and the secondary airflow (8). One end of the connecting plate (43) can be connected to the turbulence assembly (40), and the other end of the connecting plate (43) can be connected to the other end of the turbulence assembly (40). It can be connected to the outer shell (41); the slide groove (42) is provided on the side wall of the outer shell (41), and the slide groove (42) is arranged in a direction parallel to the axis of the outer shell (41); the slider (44) is placed in the slide groove (42), and the slider (44) can move along the slide groove (42); the other end of the connecting plate (43) is connected to the slider (44); the spring (45) is placed in the slide groove (42), one end of the spring (45) is connected to the slide groove (42), and the other end of the spring (45) is connected to the slider (44); the spring (45) is used to reset the slider (44) toward one end of the slide groove (42); the operating rod (46) is connected to the slider (44) for operating the slider (44) and driving the turbulence assembly (40) to move together.

2. The multi-stage pulverized coal burner according to claim 1, characterized in that, The double cone has a smaller diameter at both ends and a larger diameter in the middle. The double cone is connected to one end of the connecting plate (43). The axis of the double cone coincides with the axis of the outer shell (41). One end of the double cone faces the inner combustion cylinder (2) and can be placed inside the inner combustion cylinder (2). And / or, the single cone (402) is a cone or a frustum, the single cone (402) is connected to one end of the connecting plate (43), the axis of the single cone coincides with the axis of the outer shell (41), the small end of the single cone (402) faces the mixed airflow (6), and the portion of the mixed airflow (6) entering the channel (9) after being turbulent by the single cone (402) increases; And / or, the swirling fluid (404) includes a central cylinder connected to one end of the connecting plate (43), the axis of the central cylinder coincides with the axis of the outer shell (41), and the outer edge of the central cylinder is provided with turbulence fan blades. The mixed airflow (6) can rotate into the channel (9) or the inner combustion cylinder (2) after being turbulent by the swirling fluid (404), and the portion entering the channel (9) increases.

3. The multi-stage pulverized coal burner according to claim 1, characterized in that, The outer edge of the annular body (403) is connected to the side wall of the outer shell (41) or one end of the connecting plate (43). The axis of the annular body coincides with the axis of the outer shell (41). The portion of the mixed airflow (6) entering the inner combustion cylinder (2) after being turbulent by the annular body (403) is increased.

4. The multi-stage pulverized coal burner according to claim 1, characterized in that, The outer combustion cylinder (1) includes a first bent pipe section (101), a first tapered section (102), and a first straight pipe section (103). The diameter of the first bent pipe section (101) is larger than the diameter of the first straight pipe section (103). One end of the first bent pipe section (101) is connected to the first straight pipe section (103) via the first tapered section (102). The mixed airflow (6) is introduced by the first bent pipe section (101) and flows sequentially through the first bent pipe section (101) and the first tapered section (102) before being discharged from the first straight pipe section (103).

5. The multi-stage pulverized coal burner according to claim 4, characterized in that, The internal combustion cylinder (2) includes a second bend section (201), a second tapered section (202), a second straight section (203), a third tapered section (204), and a third straight section (205). The diameter of the second bend section (201) is greater than the diameter of the second straight section (203) and the diameter of the third straight section (205). One end of the second bend section (201) is connected to the second straight section (203) via the second tapered section (202), and the other end of the second bend section (201) is connected to the third tapered section (204) and the third straight section (205). The shapes of the second bend section (201) and the first bend section (101), the second tapered section (202) and the first tapered section (102), and the second straight section (203) and the first straight section (103) are adapted to each other.

6. The multi-stage pulverized coal burner according to claim 5, characterized in that, The internal combustion cylinder (2) also includes a fourth tapered section (206), which is a conical cylinder with one end larger than the other. Either end of the fourth tapered section (206) is connected to the third straight section (205). The primary airflow (7) enters through the fourth tapered section (206) and flows sequentially through the third straight section (205), the third tapered section (204), the second bend section (201), and the second tapered section (202) before being discharged from the second straight section (203).

7. The multi-stage pulverized coal burner according to claim 5 or 6, characterized in that, The diameter of the third straight section (205) is D. B1 The diameter of the first bend (101) is D. B2 The diameter at the maximum diameter of the bipyramidal body is D. T The vertical distance from the small end of the bipyramid to the center of the bipyramid is H, where D B1 / D B2 =0.3-0.6, D T ≤D B2 H>D T .

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