A low-load stable combustion and ignition method, device and application

Abstract

The present invention discloses a low-load stable combustion and ignition method, device and application, wherein the stable combustion and ignition device comprises a pulverized coal burner and a pulverized coal pipe; the pulverized coal pipe is provided with a branch pipe, and the side wall of the pulverized coal burner is provided with a stable combustion support burner, and the pulverized coal in the branch pipe is divided into a dilute phase pulverized coal airflow and a concentrated pulverized coal airflow through a pulverized coal concentrator, and is respectively connected to the dilute phase pulverized coal airflow inlet and the dense phase pulverized coal airflow inlet of the stable combustion support burner; the tail end of the stable combustion support burner is provided with a pilot oil gun. The low-load stable combustion and ignition device of the present invention increases the concentration of pulverized coal entering the stable combustion support burner through a pulverized coal concentration unit, so that the pulverized coal is easier to ignite in the stable combustion support burner, and then the pulverized coal flame enters the pulverized coal burner, ignites more pulverized coal, and realizes the long-term stable operation of the coal-fired unit of the thermal power plant under low-load conditions, for example, when the unit is in a deep peak load regulation of less than 30%, the flexibility, safety and stability of its operation are guaranteed, and the furnace fire extinguishing, pulverized coal explosion and other phenomena do not occur.

Description

Technical Field

[0001] The invention relates to the field of coal-fired boiler equipment for thermal power generating sets, in particular to a low-load stable combustion and ignition device. Background Art

[0002] With the rapid development of new energy power technologies such as photovoltaics and wind power, deep peak load regulation and low-load operation of coal-fired units will become the norm, and the flexibility transformation of thermal power units is imperative. All power generation companies should plan ahead, seize opportunities, give full play to their own advantages, and make technical and condition reserves in advance. The peak load regulation of thermal power units is related to many factors, including furnace flame stability, boiler water circulation, tail denitrification flue gas temperature, etc., and is related to the economy, environmental protection, and safety of unit operation, and corresponding solutions should be available. This research topic only focuses on the safe and stable combustion of power plant pulverized coal boilers using direct current burners under long-term low loads, as well as fuel-saving ignition during boiler startup.

[0003] The generator set of a thermal power plant is a huge system with a very complicated startup process. Once it is put into operation, it often runs for several months. The load range of the pulverized coal furnace in an ordinary power station is about 40-100%. If it is operated at a load lower than 40%, the furnace temperature of the boiler will drop, which will cause the risk of flameout. The common operation mode is to start the large oil gun to consume fuel to maintain boiler combustion. The output of a single large oil gun is about 1000-2000kg / h. If several large oil guns are put into use at the same time, the fuel consumption is considerable. In recent years, small oil gun ignition and stable combustion technology has emerged. The output of a single small oil gun has been reduced to 100-200kg / h, which can greatly reduce fuel consumption. This technology is used for unit ignition and startup, and the fuel consumption is acceptable because the unit is started less frequently (3-4 times a year) and the time is short (generally 8-10 hours). However, it is still an unbearable expense for power generation companies to use it for a long time (such as dozens of consecutive hours) or frequent low-load stable combustion. Oil is a strategic material. my country is an oil-poor country and mainly relies on imports. Saving oil and replacing oil with coal is a basic national policy, and continuous research and development of new oil-saving technologies is the direction of our major's unremitting efforts. Summary of the invention

[0004] After research, the inventors set up a small pulverized coal combustion chamber outside the boiler furnace, using the heat of the pulverized coal itself and only using very little fuel oil (about 20-30kg / h for a single burner) to ignite the pulverized coal before it enters the furnace burner. As the temperature of the combustion chamber outside the furnace rises, the output of the oil gun can continue to be adjusted down until the pulverized coal ignites by itself and runs completely without oil. Therefore, this technology ignites a large amount of pulverized coal in the pulverized coal burner and at the burner nozzle after a small amount of pulverized coal is ignited, without relying on the furnace temperature. The unit can ensure the safety and stability of its operation when the deep peak regulation is less than 30%, and there will be no furnace fire extinguishing, pulverized coal explosion and other phenomena. At the same time, it can also save a lot of fuel, with significant economic benefits.

[0005] The purpose of the present invention is to provide a stable combustion and ignition device which has a novel and unique structure, is easy to use, and can achieve long-term low-load operation; the specific technical scheme is:

[0006] A low-load stable combustion and ignition method, wherein the pulverized coal airflow in the pulverized coal pipe is divided into a mainstream and a branch flow; the pulverized coal airflow in the mainstream enters a pulverized coal burner; the pulverized coal airflow in the branch flow is divided into a dilute phase pulverized coal airflow and a dense phase pulverized coal airflow, the dense phase pulverized coal is ignited by an ignition oil gun and then burns in a stable combustion support burner, and a stable ignition energy is output from the stable combustion support burner outlet on the inner wall of the pulverized coal burner, thereby achieving stable combustion of the pulverized coal burner at low load or unit startup ignition.

[0007] Furthermore, the dilute-phase pulverized coal airflow is introduced into the combustion stabilizing support burner and burns together with the dense-phase pulverized coal in the combustion stabilizing support burner.

[0008] The present application also discloses a low-load stable combustion and ignition device, including a pulverized coal burner and a pulverized coal pipe; the pulverized coal pipe is provided with a branch pipe, and the side wall of the pulverized coal burner is provided with a stable combustion support burner, the pulverized coal in the branch pipe is divided into two paths, a dilute phase pulverized coal airflow and a dense phase pulverized coal airflow, the dilute phase pulverized coal gas is connected to the dilute phase pulverized coal airflow inlet of the stable combustion support burner; the dense phase pulverized coal airflow is connected to the dense phase pulverized coal airflow inlet of the stable combustion support burner; the tail end of the stable combustion support burner is provided with an ignition oil gun.

[0009] Furthermore, the branch pipe divides the pulverized coal into the dilute phase pulverized coal airflow and the dense phase pulverized coal airflow through a pulverized coal concentrator.

[0010] Furthermore, the pulverized coal concentrator is provided with a dilute-phase pulverized coal airflow extraction unit, and the dilute-phase pulverized coal airflow extraction unit is composed of a gas-solid separation structure and a centrifugal fan connected in series.

[0011] Furthermore, the gas-solid separation structure is composed of a separation cylinder and a separation core, the separation core is sleeved in the separation cylinder, and the separation core is composed of a plurality of conical caps and conical funnels arranged in series at intervals; the outer diameter of the conical cap is smaller than the conical funnel; the top edge of the conical funnel is fixedly connected to the inner wall of the separation cylinder, and a funnel mouth is arranged in the center.

[0012] Furthermore, the combustion chamber of the combustion stabilizing support burner is provided with a heat insulating sleeve.

[0013] Furthermore, a central combustion stabilizing cover is provided in the combustion chamber of the combustion stabilizing support burner.

[0014] Furthermore, the outer layer of the stable combustion supporting burner is provided with a combustion-supporting air channel, which is connected to the boiler secondary air wind box; and a linkage baffle with an adjustable angle is provided at the channel entering the combustion chamber.

[0015] The present invention also discloses that the low-load stable combustion and ignition device can be directly used as an ignition device for a pulverized coal burner. When the boiler is started, after ignition using the low-load stable combustion and ignition device, the pulverized coal burner does not need to rely on an auxiliary oil gun to continuously supply a large amount of oil. It can maintain a stable combustion state by only relying on the heat generated by the combustion of pulverized coal in the stable combustion support burner as ignition energy.

[0016] The low-load stable combustion and ignition device of the present invention separates part of the air in the coal powder through a coal powder concentration unit, thereby increasing the concentration of the coal powder entering the stable combustion supporting burner, so that the coal powder can achieve long-term stable combustion in the stable combustion supporting burner. When the unit is subjected to deep peak regulation of less than 30%, the safety and stability of its operation are guaranteed, and phenomena such as furnace fire extinguishing and coal powder explosion will not occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The structure of the low-load stable combustion and ignition device of the present invention is shown in FIG. Figure 1 ;

[0018] Figure 2 This is a schematic diagram of the structure of the concentration unit of the low-load stable combustion and ignition device of the present invention;

[0019] Figure 3 The structure of the low-load stable combustion and ignition device stable combustion support burner of the present invention is shown in FIG. Figure 1 ;

[0020] Figure 4 The structure of the low-load stable combustion and ignition device stable combustion support burner of the present invention is shown in FIG. Figure 2 ;

[0021] Figure 5 The structure of the low-load stable combustion and ignition device of the present invention is shown in FIG. Figure 2 .

[0022] In the figure: 1. pulverized coal burner; 2. centrifugal fan; 3. gas-solid separation structure; 31. separation cylinder; 32. center connecting rod; 33. end bracket; 34. conical cap; 35. conical funnel; 4. pulverized coal pipe; 5. branch pipe; 6. gas valve; 7. tee; 8. stable combustion support burner; 81. outer cylinder; 82. insulation sleeve; 821. cross streamline blunt body; 822. spiral groove; 83. combustion-supporting air inlet; 831. swirl blade; 832. combustion-supporting air duct; 833. adjustable baffle; 84. dilute phase pulverized coal air flow inlet; 85. dense phase pulverized coal pipe; 851. center combustion pipe; 86. ignition oil gun; 87. stable combustion hood; 9. auxiliary oil gun; 10. furnace body interface; 11. bellows. DETAILED DESCRIPTION

[0023] The present invention is described more fully below using embodiments. The present invention can be embodied in many different forms and should not be construed as being limited to the exemplary embodiments described herein.

[0024] For ease of description, spatially relative terms such as "upper", "lower", "left", "right", etc. may be used herein to describe the relationship of one element or feature shown in the figure relative to another element or feature. It should be understood that, in addition to the orientation shown in the figure, the spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is inverted, the elements described as being "below" other elements or features will be positioned "above" other elements or features. Therefore, the exemplary term "lower" can include both upper and lower orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here can be interpreted accordingly.

[0025] like Figure 1 As shown, the low-load stable combustion and ignition device in this embodiment has a main part that is basically the same as the existing equipment, including a pulverized coal burner 1 and a pulverized coal pipe 4; the pulverized coal burner 1 is fixedly connected to the furnace body through the furnace body interface 10. The pulverized coal as fuel enters the pulverized coal burner 1 from the pulverized coal pipe 4, and the pulverized coal is sent into the high-temperature furnace and burns. When the unit is peak-shifted at a depth of less than 30%, the furnace temperature is low, and the pulverized coal cannot be reliably ignited after entering the furnace, which often causes fire extinguishing and deflagration. In order to avoid the above-mentioned accidents, the prior art is to maintain stable combustion of the pulverized coal burner 1 by spraying oil with a large oil gun; this will increase fuel consumption.

[0026] The difference from the existing equipment is that the low-load stabilizing combustion and ignition device in this embodiment is provided with a stabilizing combustion support burner 8 on the side wall of the pulverized coal burner 1; when the unit is in deep peak regulation of less than 30%, as long as the stabilizing combustion support burner 8 is in operation, it can ensure that the pulverized coal is ignited inside the pulverized coal burner 1, avoiding furnace fire extinguishing and explosion.

[0027] The combustion-stabilizing support burner 8 is fueled by the pulverized coal provided by the branch pipe 5 provided in the pulverized coal pipe 4, that is, a part of the pulverized coal in the pulverized coal pipe 4 enters the branch pipe 5 as the fuel of the combustion-stabilizing support burner 8. The flow cross section of the branch pipe 5 accounts for about 10% of the flow cross section of the pulverized coal pipe 4. In order to make the pulverized coal easier to ignite, the pulverized coal entering the combustion-stabilizing support burner 8 needs to be concentrated.

[0028] The concentration method is as follows: the pulverized coal in the branch pipe 5 can be separated into two paths, a dilute phase pulverized coal airflow branch and a dense phase pulverized coal airflow branch, through the tee 7; the dilute phase pulverized coal airflow branch is a bypass branch. The separated dilute phase pulverized coal airflow is connected to the dilute phase pulverized coal airflow inlet 84 of the stable combustion support burner 8; the remaining concentrated pulverized coal is connected to the pulverized coal inlet of the stable combustion support burner 8; a pilot oil gun 86 is provided at the rear end of the stable combustion support burner 8. The concentrated pulverized coal is sprayed into the combustion chamber from the dense pulverized coal inlet at the rear end of the stable combustion support burner 8 through the dense phase pulverized coal pipe 85, ignited by the pilot oil gun 86, and burned in the combustion chamber.

[0029] In this embodiment, the pulverized coal in the branch pipe 5 is divided into dilute phase pulverized coal and concentrated pulverized coal by a pulverized coal concentrator.

[0030] like Figure 2 As shown, the pulverized coal concentrator is provided with a dilute phase pulverized coal airflow extraction unit, which is composed of a gas-solid separation structure 3 and a centrifugal fan 2 connected in series. The centrifugal fan 2 generates low pressure to suck air in the pulverized coal; the gas-solid separation structure 3 prevents the pulverized coal from entering the centrifugal fan 2 along with the air. Since the centrifugal fan 2 forms a low pressure area at the upper end of the separation cylinder 31, part of the pulverized coal in the branch pipe 5 will flow to the separation cylinder 31.

[0031] The gas-solid separation structure 3 is composed of a separation cylinder 31 and a separation core, wherein the separation core is sleeved in the separation cylinder 31, and the separation core is composed of a plurality of conical caps 34 and conical funnels 35 arranged at intervals and connected in series from bottom to top; wherein, the small end of the conical cap is at the top, and the top is connected to the central connecting rod 32, and the central connecting rod 32 is fixedly connected to the inner walls of the two ends of the separation cylinder 31 by screws or welding through the end brackets 33 at both ends; the outer diameter of the conical cap is smaller than the inner diameter of the separation cylinder 31; the top edge of the conical funnel is connected to the inner wall of the separation cylinder 31 by welding or bonding, and the gap is very small; a funnel mouth is provided at the bottom of the conical funnel located in the center; a gap is left between the funnel mouth and the top of the conical cap 34.

[0032] Due to the inertia of coal powder and gravity, the coal powder content flowing to the separation cylinder 31 located in the bypass branch will be less; the air content will be greater, and the small amount of coal powder carried in the air will be blocked by the separation core, and most of it will gather and fall back to the branch pipe 5, and finally the coal powder concentration flowing to the concentrated coal powder inlet will be about 30% higher than the coal powder concentration in the main pipe, which can reach a concentration that is easier to ignite.

[0033] Since the outer diameter of the conical cap is smaller than that of the conical funnel, part of the coal powder entering from the lower conical cap hits the conical funnel wall and falls down; a small amount of coal powder will enter the upper layer from the middle funnel mouth for further processing. After the coal powder gathers, the gravity is greater than the wind force and other factors and falls from the funnel mouth, overcomes the airflow resistance, returns to the branch pipe 5, and is then dispersed by the coal powder flow in the branch pipe 5, and flows to the concentrated coal powder entrance with most of the coal powder. The coal powder enters the funnel cavity from the funnel mouth of the first-stage conical funnel with the airflow through the outer edge of the first-stage conical cap; the air will form turbulence in the semi-enclosed hollow of the conical cap 34, guiding part of the coal powder to flow into the hollow part, hit the wall of the hollow cavity and fall or be adsorbed; the semi-enclosed blind cavity between the outer edge of the conical funnel and the inner wall of the separation cylinder 31 will also form turbulence, guiding part of the coal powder to flow into the blind cavity part, hit the wall of the blind cavity and fall or be adsorbed; the first-stage concentration is completed.

[0034] After two to three stages of concentration, the amount of pulverized coal entering the centrifugal fan 2 is reduced; not only is the pulverized coal concentrated, but also the damage of the pulverized coal to the centrifugal fan blades is reduced.

[0035] like Figure 3 As shown, the combustion chamber of the stable combustion support burner 8 is composed of an outer tube 81 and an insulating sleeve 82; the insulating sleeve 82 is arranged in the outer tube 81, and is made of high-temperature resistant heat-insulating materials such as silicon carbide, aluminum silicate, etc., which reduces the heat dissipation of the combustion chamber and is conducive to maintaining the high temperature in the combustion chamber.

[0036] A wedge-shaped cross-shaped streamlined bluff body 821 is arranged in the insulation sleeve 82; the wedge-shaped cross-shaped streamlined bluff body 821 can be integrally formed with the insulation sleeve 82 or separately manufactured; the wedge-shaped cross-shaped streamlined bluff body 821 causes the flame airflow to generate vortices on the back of the wedge-shaped bluff body, which is beneficial to increasing the temperature of the combustion chamber.

[0037] In order to make the coal powder burn more fully in the secondary combustion chamber, a combustion-supporting air inlet 83 is also provided at the front end of the secondary combustion chamber. The combustion-supporting air inlet 83 is preferably arranged tangentially so that the combustion-supporting air rotates in the combustion chamber. A swirl blade 831 may also be provided at the combustion-supporting air outlet to rapidly increase the temperature of the secondary combustion chamber to about 800°C. In this way, when the pilot oil gun 86 stops working, the coal powder airflow will be ignited automatically after entering, achieving oil-free stable combustion.

[0038] The dense phase pulverized coal pipe 85 is arranged at the tail of the combustion stabilizing support burner 8; the end of the dense phase pulverized coal pipe 85 is a turning portion; it radially enters the inner sleeve through the turning portion and is ignited by the flame sprayed from the pilot oil gun 86. The tail of the dense phase pulverized coal pipe 85 serves as the primary combustion chamber of the combustion stabilizing support burner 8.

[0039] The turning part of the dense phase pulverized coal pipe 85 is provided with a pilot oil gun 86. The pilot oil gun 86 adopts a product of existing design, and other ignition energy such as a gas ignition gun and a plasma ignition gun can also be used, which will not be described in detail here.

[0040] You can also Figure 4 , Figure 5 As shown, a combustion stabilizing hood 87 is provided in the center of the combustion chamber of the combustion stabilizing support burner 8, which is conducive to forming a high temperature zone and self-ignition of coal powder.

[0041] The pulverized coal burner 1 is covered with a large boiler secondary air wind box (referred to as wind box 11) to provide combustion-supporting air for the furnace cavity.

[0042] A combustion-supporting air duct 832 can also be set between the insulation sleeve 82 and the outer tube 81. The combustion-supporting air duct 832 is connected to the wind box 11 through the combustion-supporting air channel to obtain combustion-supporting air, and the combustion-supporting air is heated by the insulation sleeve 82. A swirl blade 831 is set at the entrance of the combustion-supporting air duct 832 so that the combustion-supporting air forms a swirl effect at the outlet of the combustion-supporting air duct 832.

[0043] The combustion-supporting air inlet 83 may not be provided; a part of the dilute coal powder airflow inlet 84 enters the secondary combustion chamber from the front end; a swirl blade 831 is provided at the inlet of the secondary combustion chamber; the other part flows into the combustion-supporting air duct 832 added outside the heat insulation sleeve 82. The swirl blade 831 can be set to be angle-adjustable; a number of adjustable baffles 833 (manual or electric) with adjustable linkage are provided in the combustion-supporting air duct 832, and the combustion-supporting air pressure and air volume can be adjusted by changing the angle of the adjustable baffle 833. The rotating shaft of each adjustable baffle 833 passes through the outer wall of the combustion-supporting air duct 832 and is controlled by a torsion bar. One end of the torsion bar is fixedly connected to the rotating shaft of the adjustable baffle 833, and the other end is fixed to the linkage ring. When the linkage ring rotates, it can drive all the adjustable baffles 833 to change their angles. The rotation of the linkage ring is driven by the existing technology, which will not be repeated here.

[0044] The front end of the pilot oil gun 86 is arranged in the primary combustion chamber of the stable combustion support burner 8. The concentrated dense phase coal powder airflow enters the primary combustion chamber through the dense coal powder inlet; a central combustion tube 851 is arranged in the primary combustion chamber, and the central combustion tube 851 divides the primary combustion chamber into two parts, the inner and outer parts. The coal powder near the center has a higher concentration and is first ignited by the flame sprayed by the pilot oil gun 86, and the primary combustion chamber heats up rapidly; the coal powder in the dilute phase coal powder airflow flowing through the outside of the central combustion tube 851 is lower in concentration than that in the central combustion tube 851; the flow rate is faster; it flows through the tail end of the central combustion tube 851, is ignited by the coal powder flowing out of the central combustion tube 851, and participates in the combustion; the coal powder burns more violently.

[0045] The secondary combustion chamber is arranged behind the primary combustion chamber. The outer cylinder 81 of the combustion stabilization support burner 8 is fixedly connected to the outer shell provided with a dilute coal powder airflow inlet 84 through a flange. The central axis of the dilute coal powder airflow inlet 84 deviates from the central axis of the outer shell, so as to facilitate the formation of a rotating airflow after the dilute coal powder airflow enters tangentially. The outlet of the dilute coal powder airflow pipeline is arranged at the front end of the secondary combustion chamber. The air content in the dilute coal powder airflow is relatively high, and it can be used as combustion-supporting air in the secondary combustion chamber; although the coal powder contained in the dilute coal powder airflow is small, it can also be fully utilized as fuel.

[0046] A spiral groove 822 is provided on the inner wall of the heat insulating sleeve 82 to induce swirl of the flame, enhance the stagnation effect, and increase the furnace temperature.

[0047] The working principle of the stable combustion support burner 8 in this embodiment is: when the load needs to be reduced, the dense phase coal powder entering from the dense phase coal powder inlet is ignited by the ignition oil gun 86; it enters the combustion chamber through the dense phase coal powder pipe 85; because the centrifugal fan 2 draws away part of the air, the dense phase coal powder airflow velocity is reduced, and it spontaneously ignites in the high temperature area in the secondary combustion chamber, and a stable flame is formed at the outlet of the secondary combustion chamber, which can continuously ignite the coal powder in the coal powder burner 1, achieving an oil-free stable combustion effect.

[0048] The stable combustion support burner 8 in this embodiment can be used directly for starting ignition; an auxiliary oil gun 9 can also be set on the side wall of the coal powder burner 1. When the stable combustion support burner 8 cannot be used due to a fault, the auxiliary oil gun 9 can be enabled for ignition to improve the reliability of the system. At the inlet end of the branch pipe 5, a gas valve 6 can be set. When the gas valve 6 is not opened at high load, the coal powder does not enter the branch pipe 5; when the deep peak regulation is performed, the gas valve 6 is opened, the coal powder enters the branch pipe 5, and the stable combustion support burner 8 is ignited for stable combustion. In this way, the auxiliary oil gun 9 can also be used for direct ignition when the unit is started; when the deep peak regulation of the unit is less than 30%, the stable combustion support burner 8 is used for stable combustion, which is beneficial to prolong the life of the stable combustion support burner 8.

[0049] The present invention also discloses that the low-load stable combustion and ignition device can be directly used as an ignition device for a pulverized coal burner. When the boiler is started, after ignition using the low-load stable combustion and ignition device, the pulverized coal burner does not need to rely on an auxiliary oil gun to continuously supply a large amount of oil; it can maintain a stable combustion state by only relying on the heat generated by the combustion of pulverized coal in the stable combustion support burner as ignition energy.

[0050] The above examples are only used to illustrate the present invention. In addition, there are many different implementations. These implementations are all conceivable by those skilled in the art after understanding the concept of the present invention. Therefore, they are not listed here one by one.

Claims

1. A low-load stable combustion and ignition device, comprising a pulverized coal burner and a pulverized coal pipe; characterized in that: The pulverized coal pipe is provided with a branch pipe, and a stable combustion support burner is provided on the side wall of the pulverized coal burner. The pulverized coal in the branch pipe is divided into two paths: a dilute phase pulverized coal airflow and a dense phase pulverized coal airflow. The dilute phase pulverized coal airflow is connected to the dilute phase pulverized coal airflow inlet of the stable combustion support burner; the dense phase pulverized coal airflow is connected to the pulverized coal inlet of the stable combustion support burner; a pilot oil gun is provided at the tail end of the stable combustion support burner; the branch pipe divides the pulverized coal into the dilute phase pulverized coal airflow and the dense phase pulverized coal airflow through the pulverized coal concentrator; the pulverized coal concentrator is provided with a dilute phase pulverized coal airflow extraction unit, and the dilute phase pulverized coal airflow extraction unit is composed of a gas-solid two-phase separation structure and a centrifugal fan connected in series; the gas-solid two-phase separation structure is composed of a separation cylinder and a separation core, the separation core is sleeved in the separation cylinder, and the separation core is composed of a plurality of tapered caps and tapered funnels arranged in series at intervals; the outer diameter of the tapered cap is smaller than the tapered funnel; the top edge of the tapered funnel is fixedly connected to the inner wall of the separation cylinder, and a funnel mouth is provided in the center.

2. The low-load combustion stabilization and ignition device according to claim 1, characterized in that: The stable combustion support burner is provided with a dilute coal powder interface, which enters tangentially along the volute-shaped air duct, and the dense coal powder airflow enters the central tube combustion chamber from the elbow. There is a sleeve inside, and the coal powder in the inner sleeve is ignited and then ignites the outer layer of coal powder.

3. The low-load combustion stabilization and ignition device according to claim 2, characterized in that: The combustion chamber of the combustion stabilizing support burner is provided with a spiral groove heat insulation sleeve.

4. The low-load combustion stabilization and ignition device according to claim 2, characterized in that: The combustion chamber of the combustion stabilizing support burner is provided with a combustion stabilizing cover.

5. The low-load combustion stabilization and ignition device according to claim 2, characterized in that: The outer layer of the stable combustion supporting burner is provided with a combustion-supporting air channel which is connected to the large secondary air wind box of the boiler.

6. The low-load stable combustion and ignition method of the low-load stable combustion and ignition device according to claim 1, characterized in that: The pulverized coal airflow in the pulverized coal pipe is separated into a branch flow from the main flow; the pulverized coal airflow in the main flow enters the pulverized coal burner; the pulverized coal airflow in the branch flow is divided into two paths: a dilute phase pulverized coal airflow and a dense phase pulverized coal airflow. After the dense phase pulverized coal airflow is ignited by the ignition oil gun, it burns in the stable combustion support burner. The stable combustion support burner outlet on the inner wall of the pulverized coal burner outputs stable ignition energy, thereby realizing stable operation of the pulverized coal burner under low load conditions. The device can also be used for normal start-up and ignition of the unit.

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