Self-stable combustion burner for low-volatility pulverized coal and burner control method

Abstract

The invention provides a self-stable combustion burner for low-volatility pulverized coal and a burner control method.The burner comprises a burner body, a primary air duct assembly, a flow guide assembly and a heating element, and the burner body comprises an air inlet section, a front conical section and a rear conical section which are sequentially connected in the extending direction of the burner body; the primary air duct assembly comprises a primary air duct body, at least part of the primary air duct body is arranged in the combustor body, the flow guide assembly comprises a first flow guide part and blades, the first flow guide part is arranged around the primary air duct body in the circumferential direction of the primary air duct body, and the first flow guide part is located at an inlet of the combustor body. A secondary air channel is defined between the first flow guide part and the wall face of the burner body, the blades are arranged in the secondary air channel, and the heating part is connected with the first flow guide part and located at the end, away from an inlet of the burner body, of the first flow guide part. The combustor has the advantages of being good in economical efficiency and high in reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of pulverized coal burners, and in particular, to a self-stabilizing combustion burner for low-volatile pulverized coal and a burner control method. Background Art

[0002] The deep peak shaving operation of coal-fired power units is a key measure to promote the construction of a new energy system and steadily achieve the "dual carbon" goal, which is of great significance to the sustainable development of the power industry. Common ignition and stable combustion technologies such as plasma ignition and oil-assisted combustion have certain limitations. The "coal igniting coal" technology, that is, the technical idea of using a small amount of pulverized coal to burn first to ignite and stabilize the main pulverized coal airflow, shows obvious advantages in terms of economy and reliability.

[0003] In related technologies, in a double-cone reverse injection burner, pulverized coal flows through the primary air duct and is reversely injected into the ignition zone through a reflux cap to catch fire, and is ejected towards the burner outlet under the entrainment of the swirling secondary air, and a high-temperature zone is formed at the junction of the front cone and the rear cone of the burner. At the same time, under the combined action of the front cone structure of the burner and the primary air momentum, a reflux will be generated inside the burner, and this reflux will bring part of the heat in the high-temperature zone to the ignition zone, thus realizing the "coal igniting coal" technology.

[0004] However, for some inferior coals, especially low-volatile pulverized coal, to achieve self-sustaining combustion of "coal igniting coal", more heat is required in the ignition zone. However, under typical working conditions, the heat brought by the reflux from the high-temperature zone is relatively insufficient. There are two common engineering solutions: the first is not to introduce additional heat sources, and by reasonably distributing the air, the residence time of the pulverized coal in the burner is extended to ensure that the reflux brings enough heat to the ignition zone, but this will easily cause the temperature in the high-temperature zone to exceed the ash melting point of the coal, thereby exacerbating the coking problem; the second is to introduce additional heat sources in the ignition zone, that is, to use an oil gun to provide heat for the ignition zone, but the long-term co-combustion of diesel not only has a high cost, but also causes problems such as carbon deposition, and is easy to damage the burner and the bag filter. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems in the related technologies to some extent.

[0006] To this end, an embodiment of the present invention provides a self-stabilizing combustion burner for low-volatile pulverized coal, which not only avoids the problem of exacerbating coking due to the extension of the residence time of the pulverized coal resulting in the temperature in the high-temperature zone exceeding the ash melting point of the coal, but also avoids problems such as high cost, carbon deposition, and damage to the burner and the bag filter caused by using an oil gun, and has the advantages of good economy and high reliability.

[0007] The self-stabilizing combustion burner for low-volatile pulverized coal according to an embodiment of the present invention includes:

[0008] A burner body, which includes an air inlet section, a front cone section, and a rear cone section that are sequentially connected along the extending direction of the burner body.

[0009] A primary air duct assembly, which includes a primary air duct body, and at least a part of the primary air duct body is disposed inside the burner body.

[0010] A flow guiding assembly, which includes a first flow guiding member and blades. The first flow guiding member is arranged around the primary air duct body in the circumferential direction of the primary air duct body, and the first flow guiding member is located at the inlet of the burner body. A secondary air duct is defined between the first flow guiding member and the wall surface of the burner body, and the blades are disposed inside the secondary air duct.

[0011] A heating member, which is connected to the first flow guiding member and is located at one end of the first flow guiding member away from the inlet of the burner body.

[0012] The low-volatile pulverized coal self-stabilizing combustion burner according to the embodiment of the present invention can form a specific flow field inside the burner, so that the pulverized coal can be better mixed and burned during the combustion process, and it helps to form a recirculation, bringing the heat in the high-temperature zone back to the ignition zone. By using the heating member, the problem that the heat brought by the recirculation from the high-temperature zone is relatively insufficient under typical working conditions is made up, the problem of coking aggravation caused by the temperature in the high-temperature zone exceeding the ash melting point of the coal due to the extension of the pulverized coal residence time is avoided, and the problems of high cost, carbon deposition, and damage to the burner and bag filter caused by using an oil gun are also avoided, having better economy and reliability.

[0013] In some embodiments, the secondary air duct includes a secondary main air duct. The secondary main air duct includes a first section and a second section that are connected along the flowing direction of the secondary air. The blades are disposed inside the second section. In the direction from the inlet of the burner body to the outlet of the burner body, the cross-sectional area of the first section gradually decreases.

[0014] In some embodiments, the low-volatile pulverized coal self-stabilizing combustion burner according to the embodiment of the present invention further includes a tertiary air duct body. The flowing direction inside the tertiary air duct body is the same as the flowing direction inside the primary air duct body. An air duct hole is formed on the wall surface of the front cone section. The air duct hole communicates the tertiary air duct body with the front cone section, and the included angle between the extending direction of the tertiary air duct body and the extending direction of the air duct hole is less than 90 degrees.

[0015] In some embodiments, the side surface of the heating member away from the burner body is a concave arc surface.

[0016] In some embodiments, the low-volatile pulverized coal self-stabilizing combustion burner according to the embodiments of the present invention further includes a heat insulation member. In the direction from the inlet of the burner body to the outlet of the burner body, the heat insulation member is disposed between the first flow guiding member and the heating member. The heat insulation member has a groove, and the opening of the groove faces the outlet of the burner body, and the heating member is disposed in the groove.

[0017] In some embodiments, the flow guiding assembly further includes a second flow guiding member. The second flow guiding member is disposed in the burner body, and the second flow guiding member is located on the side of the first flow guiding member away from the inlet of the burner body. The side surface of the second flow guiding member adjacent to the burner body is a concave arc surface, and the distance between the second flow guiding member and the side wall of the burner body is less than the distance between the first flow guiding member and the side wall of the burner body.

[0018] In some embodiments, the secondary air duct further includes a secondary auxiliary air duct. The secondary auxiliary air duct is defined between the inner peripheral wall of the first flow guiding member and the outer peripheral wall of the primary air duct body. The flow guiding assembly further includes a third flow guiding member. The third flow guiding member is connected to the primary air duct body and is disposed adjacent to the heating member. In the extending direction of the burner body, there is a gap between the third flow guiding member and the heating member. One end of the heat insulation member adjacent to the main secondary air duct has a protrusion, and the protrusion extends towards the outlet of the burner body.

[0019] The burner control method according to the embodiments of the present invention is implemented by the low-volatile pulverized coal self-stabilizing combustion burner according to any one of the above embodiments, and includes the following steps:

[0020] Real-time monitor the combustion condition of the burner and the coal quality information of the pulverized coal;

[0021] Determine the flame intensity inside the burner and the coal quality information of the pulverized coal, and change the heating power of the heating member and the secondary air volume of the secondary air duct;

[0022] According to the combustion condition of the burner, determine and adjust the wall temperature of the high-temperature zone inside the burner, and change the flow rate of the tertiary air and the proportion of the flow direction of the secondary air according to the wall temperature.

[0023] In some embodiments, changing the heating power of the heating member includes the following steps:

[0024] When the volatile value of the pulverized coal is greater than or equal to the preset volatile value, turn off the heating member;

[0025] The volatile value of the pulverized coal is less than the preset volatile value, and the input power P of the heating element is adjusted, where P = Q × [k × (25% - V) + m × (d - 20)], where V is the volatile content, d is the particle size of the pulverized coal, Q is the calorific value of the pulverized coal, k is the volatile adjustment coefficient, and m is the particle size adjustment coefficient.

[0026] In some embodiments, adjusting the wall temperature of the high-temperature zone inside the burner includes the following steps:

[0027] When the wall temperature is higher than the preset temperature value, increase the tertiary air volume;

[0028] When the wall temperature is lower than or equal to the preset temperature value, reduce the tertiary air volume to ensure the wall temperature Δα3, where Δα3 = c × (T - T set ) × q, where T is the current wall temperature, T set is the set temperature, c is the adjustment coefficient, and q is the air volume required for complete combustion of the pulverized coal. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic cross-sectional view of a self-stabilizing combustion burner for low-volatile pulverized coal according to an embodiment of the present invention.

[0030] Figure 2 is a schematic diagram of the internal flow of a self-stabilizing combustion burner for low-volatile pulverized coal according to an embodiment of the present invention.

[0031] Figure 3 is a schematic diagram of the internal flow of a self-stabilizing combustion burner for low-volatile pulverized coal according to another embodiment of the present invention.

[0032] REFERENCE SIGNS:

[0033] 1, Burner body, 11, Air inlet section, 12, Front cone section, 13, Rear cone section,

[0034] 2, Primary air duct assembly, 21, Primary air duct body, 22, Return cap,

[0035] 3, Flow guiding assembly, 31, First flow guiding member, 32, Blade, 33, Secondary air duct, 331, Secondary main air duct, 3311, First section, 3312, Second section, 332, Secondary auxiliary air duct, 34, Second flow guiding member, 35, Third flow guiding member,

[0036] 4, Heating element,

[0037] 5, Tertiary air duct body,

[0038] 6, Air duct hole,

[0039] 7, Heat insulation member, 71, Protrusion. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] Embodiments of the present invention will be described in detail below. 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 a limitation of the present invention.

[0041] As Figures 1-3 shown, the low-volatile pulverized coal self-stabilizing combustion burner of the embodiment of the present invention includes: a burner body 1, a primary air duct assembly 2, a guiding assembly 3, and a heating element 4, where Figure 2 and Figure 3 the arrow directions in indicate the flow conditions of the internal flow field of the burner body.

[0042] The burner body 1 includes an air inlet section 11, a front cone section 12, and a rear cone section 13 that are sequentially connected along the extending direction of the burner body 1. The primary air duct assembly 2 includes a primary air duct body 21, and at least a part of the primary air duct body 21 is disposed inside the burner body 1. The guiding assembly 3 includes a first guiding member 31 and vanes 32. The first guiding member 31 is arranged around the primary air duct body 21 in the circumferential direction of the primary air duct body 21, and the first guiding member 31 is located at the inlet of the burner body 1. A secondary air duct 33 is defined between the first guiding member 31 and the wall surface of the burner body 1, and the vanes 32 are disposed in the secondary air duct 33. The heating element 4 is connected to the first guiding member 31 and is located at one end of the first guiding member 31 away from the inlet of the burner body 1.

[0043] Specifically, as Figure 1 and Figure 2 shown, the burner body 1 is sequentially an air inlet section 11, a front cone section 12, and a rear cone section 13 from left to right. The air inlet section 11 is the inlet of the burner body 1, and the outlet of the burner body 1 is provided at the rear cone section 13. The burner body 1 provides the space required for pulverized coal combustion. The right end of the primary air duct body 21 is disposed inside the burner body 1, and the left end of the primary air duct body 21 is used to introduce primary air. The first guiding member 31 is sleeved on the circumference of the primary air duct body 21, and a secondary air duct 33 is defined between the outer peripheral wall of the first guiding member 31 and the inner peripheral wall of the burner body 1, so as to introduce secondary air into the burner body 1 by using the secondary air duct 33. The heating element 4 is located at the right end of the first guiding member 31, so as to heat the circulating air flow on the right side of the first guiding member 31 by using the heating element 4.

[0044] It can be understood that, as Figure 1 and Figure 2As shown, the right end of the primary air duct body 21 is placed inside the burner body 1, which can accurately convey the primary air to a specific position of the burner, ensuring that the pulverized coal can smoothly enter the combustion area for combustion. The vane 32 is placed inside the secondary air duct 33, and the vane 32 can play a role in guiding and regulating the secondary air. In addition, the primary air duct assembly 2 further includes a reflux cap 22. The reflux cap 22 is arranged inside the burner and adjacent to the right end of the primary air duct body 21. The left side wall of the reflux cap 22 is provided with a reflux area, and the cross-section of the inner peripheral wall of this reflux area is "M"-shaped. So that the primary air introduced into the primary air duct body 21, under the guiding action of the reflux cap 22, flows along the peripheral wall of the primary air duct body 21 towards the inlet of the burner body 1, and the air flow flowing back towards the inlet of the burner body 1 generates convection with other air flows entering the burner body 1, thereby forming a reflux area (i.e., the ignition area) inside the burner body 1 (in the area adjacent to the first deflector 31), and a high-temperature area is formed on the side adjacent to the outlet inside the burner body 1.

[0045] Thus, as Figure 1 and Figure 2 shown, according to the air flow distribution inside the burner body 1, the heating element 4 can provide additional heat for the ignition area. For low-volatile pulverized coal, more heat is required in the ignition area to achieve self-sustaining combustion. The setting of the heating element 4 makes up for the problem that the heat brought by the reflux from the high-temperature area is relatively insufficient under typical working conditions.

[0046] In other words, the self-stabilizing combustion burner for low-volatile pulverized coal in the embodiment of the present invention can form a specific flow field inside the burner, enabling the pulverized coal to be better mixed and burned during the combustion process, and helping to form a reflux to bring the heat of the high-temperature area back to the ignition area. The setting of the heating element 4 makes up for the problem that the heat brought by the reflux from the high-temperature area is relatively insufficient under typical working conditions, avoids the problem of increased coking caused by the temperature in the high-temperature area exceeding the ash melting point of the coal due to the extended residence time of the pulverized coal, and also avoids problems such as high cost, carbon deposition, and damage to the burner and bag filter caused by using an oil gun, and has better economy and reliability.

[0047] In some embodiments, the secondary air duct 33 includes a secondary main air duct 331. The secondary main air duct 331 includes a first section 3311 and a second section 3312 connected along the flow direction of the secondary air. The vane 32 is placed inside the second section 3312. In the direction from the inlet of the burner body 1 to the outlet of the burner body 1, the cross-sectional area of the first section 3311 gradually decreases.

[0048] It can be understood that, as Figure 1 and Figure 2As shown, the cross-sectional area of the first section 3311 gradually decreases. According to the principle of fluid mechanics, when fluid flows in a channel with a variable cross-section, with a certain flow rate, as the cross-sectional area of the channel decreases, the flow velocity of the fluid will increase. Therefore, the secondary air will be accelerated when flowing through the first section 3311 of the secondary main air duct 331. The accelerated secondary air can enter the combustion zone faster, enhancing the mixing effect between the secondary air and the pulverized coal carried by the primary air. More thorough mixing is conducive to the more uniform contact between the pulverized coal and oxygen, thereby improving the combustion efficiency of the pulverized coal and making the combustion more complete.

[0049] That is to say, the secondary air enters the second section 3312 after being accelerated through the first section 3311, and the blades 32 are arranged in the second section 3312. The accelerated secondary air impacts the blades 32, and the blades 32 can further adjust and control the flow direction and velocity of the secondary air, thereby optimizing the flow field distribution within the entire burner. A reasonable flow field distribution helps to form a stable combustion flame, improve the combustion stability, and plays an important promoting role in the self-stable combustion of low-volatile pulverized coal.

[0050] Thus, the secondary air that is accelerated and adjusted by the blades 32 can participate more effectively in the combustion process. It can deliver more oxygen to the high-temperature zone, promoting more intense combustion reactions in the high-temperature zone. At the same time, it also helps to better transfer and diffuse the heat in the high-temperature zone, further improving the heat exchange situation within the burner and making the combustion process more stable and efficient. Moreover, this structural design can, to a certain extent, reduce the generation of local high temperatures, lower the risk of coking, and extend the service life of the burner.

[0051] In some embodiments, the low-volatile pulverized coal self-stable combustion burner of the embodiment of the present invention further includes a tertiary air duct body 5. The flow direction within the tertiary air duct body 5 is the same as that within the primary air duct body 21. Air duct holes 6 are opened on the wall surface of the front cone section 12. The air duct holes 6 connect the tertiary air duct body 5 and the front cone section 12, and the included angle between the extending direction of the tertiary air duct body 5 and the extending direction of the air duct holes 6 is less than 90 degrees.

[0052] It can be understood that, as Figure 1 and Figure 2 shown, the tertiary air duct body 5 is connected to the front cone section 12 through the air duct holes 6, and can supplement additional air (oxygen) to the combustion zone of the front cone section 12. For the combustion of low-volatile pulverized coal, sufficient oxygen supply is one of the key factors for achieving efficient combustion. The additional oxygen supplement can enable the pulverized coal to fully react with oxygen during the combustion process, improve the combustion efficiency, reduce the generation of incomplete combustion products, and thus reduce energy waste.

[0053] In addition, since the flow direction in the tertiary air duct body 5 is the same as that in the primary air duct body 21, and the included angle α between the extending direction of the tertiary air duct body 5 and the extending direction of the duct hole 6 is less than 90°, so that the tertiary air can enter the front cone section 12 in a relatively smooth manner. This helps the tertiary air to better mix with the pulverized coal carried by the primary air and the secondary air, making the combustion more uniform and stable. Uniform combustion can avoid local overheating or overcooling, and reduce the occurrence of problems such as coking.

[0054] Preferably, there are multiple duct holes 6, and the multiple duct holes 6 are arranged at intervals in the circumferential direction of the front cone section 12. It can be understood that the multiple duct holes 6 are arranged at intervals in the circumferential direction of the front cone section 12, so that the tertiary air can enter the combustion area evenly from multiple positions of the front cone section 12. This uniform air intake method can further optimize the flow field distribution in the burner and form a more stable combustion flame. A stable flow field helps to improve the stability and reliability of combustion, which is particularly important for the self-stable combustion of low-volatile pulverized coal.

[0055] That is to say, the tertiary air is introduced into the combustion area through the duct hole 6. Part of the combustion-supporting air enters the burner through the tertiary air path, optimizing the air distribution, strengthening the air dynamic field in the combustion area, and at the same time increasing the residence time and uniform distribution of the pulverized coal in the combustion area. Of course, the introduction of the tertiary air can be flexibly adapted to different coal types and combustion requirements by adjusting the width and air volume of the duct hole 6.

[0056] In some embodiments, the side surface of the heating element 4 away from the burner body 1 is a concave arc surface. It can be understood that, as Figure 1 and Figure 2 shown, the right side surface of the heating element 4 is a concave arc surface, that is, the concave arc surface has a larger surface area compared to a flat surface. When the heating element 4 works, the larger surface area means that it can have more contact area with the surrounding gas or pulverized coal. Taking heat conduction as an example, more contact area can make the heat transfer to the surrounding substances more efficiently, thereby improving the heating efficiency of the gas or pulverized coal passing through this area. For low-volatile pulverized coal, faster and more sufficient heating helps it reach the ignition point faster, and then achieve more stable combustion.

[0057] In addition, the structure of the concave arc surface will cause the gas flowing through its surface to form a special flow field (that is, it is easier to form a stable ignition zone). The gas will change its flow direction under the guidance of the concave arc surface and form a certain degree of turbulence. This turbulence can enhance the mixing degree of the gas and the surface of the heating element 4, make the gas absorb the heat emitted by the heating element 4 more fully, further improve the heating effect, and significantly improve the ignition efficiency. Even when using low-quality pulverized coal, ignition can be quickly achieved through concentrated heating.

[0058] That is to say, the concave arc surface of the heating element 4 can better transfer heat to the pulverized coal, enabling the pulverized coal to rapidly increase in temperature and reach the ignition point after entering the interior of the burner. Especially for low-volatile pulverized coal, sufficient heat supply is the key to achieving ignition and self-stabilized combustion. Faster ignition of the pulverized coal can reduce the amount of unburned pulverized coal, improve combustion efficiency, and reduce energy loss.

[0059] In some embodiments, the self-stabilized combustion burner for low-volatile pulverized coal according to the embodiments of the present invention further includes a heat insulation member 7. In the direction from the inlet of the burner body 1 towards the outlet of the burner body 1, the heat insulation member 7 is disposed between the first flow guiding member 31 and the heating element 4. The heat insulation member 7 has a groove, and the opening of the groove faces the outlet of the burner body 1, and the heating element 4 is disposed in the groove.

[0060] Specifically, as Figure 1 and Figure 2 shown, the heat insulation member 7 is arranged at the right end of the first flow guiding member 31. The heat insulation member 7 is used to prevent the heat generated by the heating element 4 from being transferred to the first flow guiding member 31 and other surrounding components, so as to reduce the heat dissipation to the surrounding environment. A groove is formed on the right side of the heat insulation member 7, and the notch of the groove faces the right side. The heating element 4 is fitted in the groove.

[0061] It can be understood that the groove on the heat insulation member 7 provides a fixed installation position for the heating element 4. The opening of the groove faces the outlet of the burner body 1, which not only facilitates the installation of the heating element 4 but also ensures the stable position of the heating element 4 during the operation of the burner. The heating element 4 will not be displaced due to factors such as the impact of air flow or vibration, thus ensuring the stability and consistency of the heating effect, enabling the ignition area to continuously obtain a stable heat supply, which is beneficial to the realization of self-stabilized combustion of low-volatile pulverized coal.

[0062] That is to say, the presence of the heat insulation member 7 can effectively reduce the heat dissipation to the surrounding environment, and the heat insulation member 7 can make the heat generated by the heating element 4 more concentrated in the area that needs to be heated, such as the ignition area. This helps to improve the utilization efficiency of heat, enables the heating element 4 to more effectively provide the heat required for the combustion of low-volatile pulverized coal, and reduces energy waste.

[0063] In some embodiments, the flow guiding assembly 3 further includes a second flow guiding member 34. The second flow guiding member 34 is disposed inside the burner body, and the second flow guiding member 34 is located on the side of the first flow guiding member 31 away from the inlet of the burner body 1. The side surface of the second flow guiding member 34 adjacent to the burner body 1 is a concave arc surface, and the distance between the second flow guiding member 34 and the side wall of the burner body 1 is less than the distance between the first flow guiding member 31 and the side wall of the burner body 1.

[0064] Specifically, as Figure 1 and Figure 2As shown, the second flow guide 34 is arranged adjacent to the right end of the first flow guide 31. The second flow guide 34 can be fixedly connected to the burner body 1 or the first flow guide 31 through a connecting member. There is a gap between the second flow guide 34 and the first flow guide 31, so that part of the secondary air can flow to the heating member 4 through the gap between the second flow guide 34 and the first flow guide 31. The left side surface of the second flow guide 34 is a concave arc surface, so that part of the secondary air can flow to the heating member 4 more easily.

[0065] It can be understood that, as Figure 1 and Figure 2 shown, the distance between the second flow guide 34 and the side wall of the burner body 1 is a, and the distance between the first flow guide 31 and the side wall of the burner body 1 is b, then a < b. That is to say, the second flow guide 34 is closer to the burner body 1 relative to the first flow guide 31, so that the secondary air can be separated into two parts by the second flow guide 34. That is, a part of the secondary air flows directly into the interior of the burner body 1 through the outside of the second flow guide 34, and the other part of the secondary air flows to the heating member 4 through the gap between the second flow guide 34 and the first flow guide 31. Thus, part of the secondary air is heated by the heating member 4 and then flows into the interior of the burner body 1, increasing the temperature of the combustion area inside the burner and enhancing the ignition and combustion performance of low-volatile pulverized coal, making up for the problems of difficult ignition and insufficient heat during the combustion of low-volatile pulverized coal.

[0066] In some other embodiments, the secondary air duct 33 further includes a secondary auxiliary air duct 332. A secondary auxiliary air duct 332 is defined between the inner peripheral wall of the first flow guide 31 and the outer peripheral wall of the primary air duct body 21. The flow guide assembly 3 further includes a third flow guide 35. The third flow guide 35 is connected to the primary air duct body 21 and is arranged adjacent to the heating member 4. There is a gap between the third flow guide 35 and the heating member 4 in the extending direction of the burner body 1. The heat insulation member 7 has a protrusion 71 at one end adjacent to the main secondary air duct. The protrusion 71 extends towards the outlet of the burner body 1.

[0067] Specifically, as Figure 3 shown, the first flow guide 31 is disposed between the primary air duct body 21 and the burner body 1, and a secondary main air duct 331 is defined between the first flow guide 31 and the burner body 1. A secondary auxiliary air duct 332 is defined between the first flow guide 31 and the primary air duct body 21. The third flow guide 35 is arranged at the right end of the secondary auxiliary air duct 332 to divert the secondary air flowing through the secondary auxiliary air duct 332 to the heating member 4. The outer edge of the heat insulation member 7 is provided with a protrusion 71 extending towards the right, so that after the secondary air flows through the heating member 4, under the re-diversion effect of the protrusion 71, a local small recirculation zone is formed inside the burner body 1 to ensure that the heated secondary air is transferred to the ignition zone.

[0068] That is to say, when the secondary air passes through the first deflector 31, it is divided into two parts (i.e., passing through the main secondary air duct 331 and the secondary auxiliary air duct 332 respectively) and flows into the interior of the burner. And the secondary air flowing into through the secondary auxiliary air duct 332 flows towards the heating element 4 under the guiding action of the third deflector 35. The secondary air heated by the heating element 4 forms a small recirculation zone on the right side of the third deflector 35, causing the air flow to form a turbulent flow state in a local area, promoting the mutual mixing between different air flows. And it enables the oxygen in the secondary air to contact the pulverized coal more evenly, improving the sufficiency of the combustion reaction, further enhancing the combustion effect, and also contributing to maintaining a stable temperature distribution in the ignition zone and the combustion area.

[0069] The burner control method of the embodiment of the present invention is described below.

[0070] The burner control method of the embodiment of the present invention is implemented by the low-volatile pulverized coal self-stabilizing combustion burner in any one of the above embodiments, and includes the following steps:

[0071] The combustion condition of the burner and the coal quality information of the pulverized coal are monitored in real time. It can be understood that the combustion condition of the burner includes flame intensity, combustion stability, etc. The coal quality information of the pulverized coal includes: volatile matter, ash content, moisture content, pulverized coal particle size, pulverized coal calorific value, etc. That is, the combustion characteristics of pulverized coal with different coal qualities vary greatly, and low-volatile pulverized coal requires more heat to achieve stable combustion. By monitoring the coal quality information in real time, the combustion difficulty of the pulverized coal can be understood in advance, and combined with the combustion condition, a more reasonable control strategy can be formulated to avoid problems such as incomplete combustion and flameout.

[0072] The flame intensity inside the burner and the coal quality information of the pulverized coal are determined, and the heating power of the heating element and the secondary air volume of the secondary air duct are changed. It can be understood that the heating power is adjusted according to the volatility of the pulverized coal and the flame intensity. When the volatility value of the pulverized coal is greater than or equal to the preset volatility value, it indicates that the pulverized coal is relatively easy to burn. At this time, turning off the heating element can save energy and reduce the operating cost. When the volatility of the pulverized coal is low, in order to ensure that there is enough heat in the ignition zone to ignite the pulverized coal and maintain stable combustion, it is necessary to increase the heating power of the heating element.

[0073] The flame intensity reflects the intensity and sufficiency of combustion. If the flame intensity is weak, it may be due to insufficient oxygen supply or uneven mixing of pulverized coal and air. At this time, the secondary air volume can be appropriately increased to provide more oxygen for combustion and promote the full combustion of pulverized coal. On the contrary, if the flame intensity is too strong, it may lead to too high combustion temperature and increase the risk of coking. At this time, the secondary air volume can be appropriately reduced.

[0074] According to the combustion condition of the burner, determine and adjust the wall temperature of the high-temperature zone inside the burner, and change the flow rate of the tertiary air and the proportion of the flow direction of the secondary air according to the wall temperature. It can be understood that too high a wall temperature in the high-temperature zone is likely to cause coking problems, affecting the normal operation and service life of the burner; too low a temperature may lead to incomplete combustion. Therefore, it is necessary to adjust the wall temperature according to the combustion condition to keep it within a suitable range.

[0075] That is to say, when the wall temperature is too high, the flow rate of the tertiary air can be increased. The tertiary air can play a role in cooling the wall, reducing the wall temperature and the possibility of coking. At the same time, the tertiary air can also provide additional oxygen for combustion, promoting the full progress of combustion. When the wall temperature is too low, the flow rate of the tertiary air can be appropriately reduced to avoid too much cold air entering the burner and affecting the combustion efficiency.

[0076] In some embodiments, changing the heating power of the heating element includes the following steps: when the volatile value of the pulverized coal is greater than or equal to the preset volatile value, turn off the heating element.

[0077] When the volatile value of the pulverized coal is less than the preset volatile value, adjust the input power P of the heating element, P = Q×[k×25% - V + m×d - 20, where V is the volatile content, d is the particle size of the pulverized coal, Q is the calorific value of the pulverized coal, k is the volatile adjustment coefficient, and m is the particle size adjustment coefficient. Optionally, the value range of k is 0.4 - 0.8, and the value range of m is 0.02 - 0.3.

[0078] It should be noted that taking low-volatile pulverized coal as an example, when the volatile content V of the pulverized coal is greater than or equal to 20%, the heating element does not need to operate, and the operation of the heating element can be turned off. When the volatile content V of the pulverized coal is less than 20%, the heating element needs to provide additional heat to promote ignition.

[0079] In addition, when the average particle size of the pulverized coal is less than 20 microns and the volatile content is greater than 25%, the heating element is turned off. If the above conditions are not met, the input power P of the high-temperature heating plate.

[0080] In some embodiments, adjusting the wall temperature of the high-temperature zone inside the burner includes the following steps:

[0081] When the wall temperature is higher than the preset temperature value, increase the flow rate of the tertiary air; when the wall temperature is lower than or equal to the preset temperature value, reduce the flow rate of the tertiary air to ensure the wall temperature Δα3, Δα3 = c×(T - T set )×q, where T is the current wall temperature, T set is the set temperature, c is the adjustment coefficient, and q is the air volume required for complete combustion of the pulverized coal. Optionally, the value range of c is 0.002 - 0.006.

[0082] That is to say, when the wall temperature exceeds the set value, increase the tertiary air volume three times to reduce the wall temperature. When it is too low, reduce the tertiary air volume to ensure the wall temperature.

[0083] In the description of the present invention, it should be understood that 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. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is 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 therefore should not be construed as a limitation of the present invention.

[0084] 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, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0085] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to", "fixed", etc. shall 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 communicable 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.

[0086] 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 indirectly in 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 first feature has a higher horizontal height than 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 first feature has a lower horizontal height than the second feature.

[0087] In the present invention, the terms "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 are not necessarily directed 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 the different embodiments or examples.

[0088] 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 low-volatile pulverized coal self-stabilizing combustion burner, characterized in that, Comprising: A burner body, the burner body including an air inlet section, a front cone section, and a rear cone section that are sequentially connected along the extension direction of the burner body; A primary air duct assembly, the primary air duct assembly including a primary air duct body, at least a part of the primary air duct body being disposed inside the burner body; A flow guiding assembly, the flow guiding assembly including a first flow guiding member and vanes, the first flow guiding member being arranged around the primary air duct body in the circumferential direction of the primary air duct body, and the first flow guiding member being located at the inlet of the burner body, a secondary air duct being defined between the first flow guiding member and the wall surface of the burner body, and the vanes being disposed in the secondary air duct; A heating member, the heating member being connected to the first flow guiding member and located at one end of the first flow guiding member away from the inlet of the burner body.

2. The low-volatile pulverized coal self-stabilizing combustion burner according to claim 1, characterized in that, The secondary air duct includes a secondary main air duct, the secondary main air duct including a first section and a second section that are connected in the flowing direction of the secondary air, the vanes being disposed in the second section, and in the direction from the inlet of the burner body to the outlet of the burner body, the cross-sectional area of the first section gradually decreases.

3. The low-volatile pulverized coal self-stabilizing combustion burner according to claim 2, wherein It further includes a tertiary air duct body, the flowing direction in the tertiary air duct body being the same as the flowing direction in the primary air duct body, air duct holes being formed on the wall surface of the front cone section, the air duct holes communicating the tertiary air duct body with the front cone section, and the included angle between the extension direction of the tertiary air duct body and the extension direction of the air duct holes being less than 90 degrees.

4. The low-volatile pulverized coal self-stabilizing combustion burner according to claim 3, characterized in that, The side surface of the heating member away from the burner body is a concave arc surface.

5. The low-volatile pulverized coal self-stabilizing combustion burner according to claim 4, wherein It further includes a heat insulation member, in the direction from the inlet of the burner body to the outlet of the burner body, the heat insulation member being disposed between the first flow guiding member and the heating member, the heat insulation member having a groove, the opening of the groove facing the outlet of the burner body, and the heating member being disposed in the groove.

6. The low-volatile pulverized coal self-stabilizing combustion burner according to claim 5, characterized in that The flow guiding assembly further includes a second flow guiding member, the second flow guiding member being provided in the burner body, and the second flow guiding member being located on the side of the first flow guiding member away from the inlet of the burner body, the side surface of the second flow guiding member adjacent to the burner body being a concave arc surface, and the distance between the second flow guiding member and the side wall of the burner body being less than the distance between the first flow guiding member and the side wall of the burner body.

7. The low-volatile pulverized coal self-stabilizing combustion burner according to claim 5, characterized in that, The secondary air duct further includes a secondary auxiliary air duct, the secondary auxiliary air duct being defined between the inner peripheral wall of the first flow guiding member and the outer peripheral wall of the primary air duct body, the flow guiding assembly further including a third flow guiding member, the third flow guiding member being connected to the primary air duct body and being arranged adjacent to the heating member, and there being a gap between the third flow guiding member and the heating member in the extension direction of the burner body, and one end of the heat insulation member adjacent to the secondary air main duct having a protrusion, the protrusion extending towards the outlet of the burner body.

8. A burner control method, which is implemented by the low-volatile pulverized coal self-stabilizing combustion burner according to any one of claims 1-7, characterized in that, Including the following steps: Real-time monitoring of the combustion condition of the burner and the coal quality information of the pulverized coal; Determining the flame intensity inside the burner and the coal quality information of the pulverized coal, and changing the heating power of the heating member and the secondary air volume of the secondary air duct; Determine and adjust the wall temperature of the high-temperature zone inside the burner according to the combustion condition of the burner, and change the flow rate of the tertiary air and the proportion of the flow direction of the secondary air according to the wall temperature.

9. The burner control method according to claim 8, characterized in that, Changing the heating power of the heating element includes the following steps: When the volatile value of the pulverized coal is greater than or equal to the preset volatile value, turn off the heating element; When the volatile value of the pulverized coal is less than the preset volatile value, adjust the input power P of the heating element, P = Q × [k × (25% - V) + m × (d - 20)], where V is the volatile content, d is the particle size of the pulverized coal, Q is the calorific value of the pulverized coal, k is the volatile adjustment coefficient, and m is the particle size adjustment coefficient.

10. The burner control method according to claim 8, characterized in that, Adjusting the wall temperature of the high-temperature zone inside the burner includes the following steps: When the wall temperature is higher than the preset temperature value, increase the flow rate of the tertiary air; The wall temperature is lower than or equal to the preset temperature value, reducing the tertiary air volume to ensure the wall temperature Δα3, where Δα3 = c × (T - T set ) × q, where T is the current wall temperature, T set is the set temperature, c is the adjustment coefficient, and q is the air volume required for complete combustion of pulverized coal.

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