Boiler staged low-NOX combustion system
By designing a split-combustion air wind blower and a secondary air wind blower in the boiler graded low NOX combustion system, the problems of insufficient combustion and uneven air flow distribution in the boiler low nitrogen combustion technology are solved, and low NOX emissions and coal powder combustion are achieved Improved efficiency.
Patent Information
- Application Number
- CN202411314968.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2025-01-03
AI Technical Summary
In boiler low nitrogen combustion technology, oxygen-depleted in the main combustion area of the furnace leads to insufficient combustion, reducing boiler efficiency, and uneven distribution of rotating airflow in the combustion method of four corner cut-in circle arrangement affects the combustion and transportation process of coal powder.
Design a boiler graded low NOX combustion system, including four sets of burners at the four corners of the lower part of the furnace and four corners of the upper part of the furnace. The air duct is arranged through the split ash wind wind box and the secondary air duct to ensure the air duct. The air flow rate is low, which improves the air flow distribution characteristics, reduces the losses of coal powder and air during combustion and transportation, and achieves more uniform combustion through multi-layer secondary air and ember air nozzles.
The low emissions of NOX and the improvement of coal powder combustion efficiency are achieved, ensuring uniform temperature distribution in the furnace, improving the combustion circle effect, and reducing the loss of wind during combustion and transportation.
Smart Images
Figure CN119245022A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of boilers and boiler environmental protection, and in particular to a boiler graded low NO X Combustion system. Background Art
[0002] In order to achieve the ultra-low NOx emission target, domestic thermal power plants generally use air-staged combustion boiler low-nitrogen combustion technology, which makes the NOx emission mass concentration in the furnace better controlled after the low-nitrogen combustion transformation. However, due to the oxygen deficiency in the main combustion zone of the furnace, the volume fraction of reducing gases represented by CO increases, which easily causes incomplete combustion and reduces boiler efficiency. In the actual low-nitrogen combustion operation of the boiler, there is an obvious contradiction between boiler efficiency and furnace NOx emissions. How to effectively balance the contradiction between the two is currently a hot topic in the research of efficient, economical and environmentally friendly operation of boilers.
[0003] At present, the four-corner tangential circle combustion method based on direct current combustion technology cooperates with the ember wind system to achieve early control of fuel nitrogen through air staging and fuel staging. It is mainly achieved by forming an overall rotating airflow in the furnace. However, the rotating airflow is usually prone to uneven airflow distribution and affects the thick and thin separation effect due to the process of coal powder entering the furnace. The pressure loss generated at the integral bellows and the elbows of the pipeline for the coal powder entering the furnace may even affect the pressure and wind speed of the primary air, secondary air and ember wind due to different coal quality conditions, thereby affecting the combustion and transportation process of the coal powder. Summary of the invention
[0004] In view of the above problems, the present application provides a boiler graded low NO X The combustion system can reduce the loss of pulverized coal and primary air, secondary air and ember air during the combustion and transportation process, ensuring NO X It can not only reduce emissions, but also improve the combustion efficiency of pulverized coal.
[0005] To achieve the purpose of this application, this application provides the following technical solutions:
[0006] The present application provides a boiler graded low NO XThe combustion system comprises four groups of burner devices respectively arranged at the four corners of the lower part of the furnace and ember wind devices arranged at the four corners of the upper part of the furnace, wherein each group of the burner devices comprises at least two burners and at least three layers of secondary air nozzles, and each of the ember wind devices comprises at least one layer of ember wind nozzles; a left secondary air wind box is arranged at the lower part of the left wall of the furnace, and a left ember wind wind box is arranged at the upper part of the left wall of the furnace; the second corner burner device and the third corner burner device of the four groups of burner devices are connected to the left secondary air wind box at the same time, and the second corner ember wind device and the third corner ember wind device of the four corner ember wind devices are connected to the left ember wind wind box at the same time; a right secondary air wind box is arranged at the lower part of the right wall of the furnace, and a right ember wind wind box is arranged at the upper part of the right wall of the furnace, The first-corner burner device and the fourth-corner burner device in the four groups of burner devices are connected to the right secondary air wind box at the same time, and the first-corner burner wind device and the fourth-corner burner wind device in the four corners are connected to the right burner wind box at the same time; wherein, the left wall and the right wall are located at the relatively outer sides of the box body of the furnace, and the second-corner burner device and the third-corner burner device are respectively located at the second corner and the third corner corresponding to the left wall, and the second-corner burner wind device is located at the second corner, and the third-corner burner wind device is located at the third corner; the first-corner burner device and the fourth-corner burner device are respectively located at the first corner and the fourth corner corresponding to the right wall, and the first-corner burner wind device is located at the first corner, and the fourth-corner burner wind device is located at the fourth corner;
[0007] The left secondary air box and the left ember air box are connected to the blower outlet through the first air duct and the second air duct respectively; the right secondary air box and the right ember air box are connected to the blower outlet through the third air duct and the fourth air duct respectively.
[0008] In a possible implementation, the first air duct and the second air duct are led out from the top and bottom of the output horizontal pipe section of the blower outlet respectively; based on the first guide air duct, the airflow in the left secondary air box is led out from the left and right to the second angle burner device and the third angle burner device respectively, forming the secondary air in the second angle burner device and the third angle burner device; based on the second guide air duct, the airflow in the left ember air box is led out from the left and right to the second angle ember air device and the third angle ember air device respectively, forming the ember wind in the second angle ember wind device and the third angle ember wind device.
[0009] In a possible implementation, each group of the burner devices includes several horizontal rich-lean burners, and a block is provided inside the inlet end of each of the horizontal rich-lean burners of the second-angle burner device and the third-angle burner device. The block is located at the outer corner of the airflow through the inlet section.
[0010] In a possible implementation, the first stopper corresponding to the horizontal thick-lean burner at the upper part of the second angle burner device is located at the upper right of the corresponding inlet section; the second stopper corresponding to the horizontal thick-lean burner at the lower part of the second angle burner device is located at the lower left of the corresponding inlet section; the area of the third stopper corresponding to the horizontal thick-lean burner at the middle position of the second angle burner device is smaller than the area of the first stopper / the second stopper.
[0011] In a possible implementation, the center elevation of the left ember wind box is 34-35.2 m; the center elevation of the output horizontal pipe section is 31.5 m.
[0012] In a possible implementation, the at least two layers of secondary air nozzles include a first secondary air nozzle and a second secondary air nozzle, the first secondary air nozzle is a fixed nozzle, and the second secondary air nozzle is a swing nozzle.
[0013] In one possible implementation, the at least two layers of secondary air nozzles include eight layers of secondary air nozzles arranged longitudinally, at least one layer of the secondary air nozzles in the bottom layer is a fixed nozzle, and the seven layers of secondary air nozzles in the upper layer are swinging nozzles; the swing amplitude of the swinging nozzle is ±15°.
[0014] In a possible implementation, the ember wind device includes four layers of ember wind nozzles arranged longitudinally.
[0015] In a possible implementation, a vertical blunt body is provided between the rich coal powder room and the light coal powder room of each of the horizontal rich-lean burners; horizontal stabilizing teeth are arranged in the rich coal powder room; and the outlet blunt plate of each of the horizontal rich-lean burners is vertical.
[0016] In a possible implementation, a booster fan is provided at the end of the air duct corresponding to the inlet of the ember air wind box.
[0017] The present application provides a boiler graded low NO XThe combustion system is provided with a separate ember air box and a secondary air box on the outer wall on the opposite side of the furnace, and the conveying pipelines of the secondary air system and the ember air system are arranged respectively, wherein the air duct and the air box are fully considered, so that the air velocity in each air duct and the air box is low, the distribution characteristics are improved, the temperature distribution in the furnace is more uniform, the combustion cutting effect in the furnace is better, the loss of pulverized coal and primary air, secondary air and ember air in the combustion and conveying process is reduced, and NO X Low emissions, improved coal powder combustion rate and boiler efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings are used to provide a further understanding of the present application and form a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation to the present application.
[0019] Figure 1 The boiler graded low NO provided in the embodiment of the present application X Schematic diagram of the combustion system;
[0020] Figure 2 A schematic diagram of the structure of a burner device of any group provided in an embodiment of the present application;
[0021] Figure 3 A schematic diagram of the structure of the air guide duct provided in the embodiment of the present application;
[0022] Figure 4 A schematic diagram of the top view of the air guide duct provided in an embodiment of the present application;
[0023] Figure 5 A schematic diagram of the structure of the burner outlet provided in an embodiment of the present application;
[0024] Figure 6 The boiler graded low NO provided in the embodiment of the present application X Schematic diagram of the pulverized coal ring structure formed by the combustion system.
[0025] Reference numerals:
[0026] 1, secondary air nozzle No. 1; 2, sixth burner; 3, secondary air nozzle No. 2; 4, secondary air nozzle No. 3; 5, fourth burner; 6, secondary air nozzle No. 4; 7, secondary air nozzle No. 5; 8, secondary air nozzle No. 6; 9, secondary air nozzle No. 7; 10, secondary air nozzle No. 8; 11, horn No. 2; 12, horn No. 3; 13, horn No. 1; 14, horn No. 4. DETAILED DESCRIPTION
[0027] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0028] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of this application, unless otherwise specified, "plurality" means two or more.
[0029] In order to achieve the ultra-low emission target of nitrogen oxides (NOx), domestic thermal power plants generally use air-staged combustion boiler low-nitrogen combustion technology, which makes the NOx emission mass concentration in the furnace better controlled after the low-nitrogen combustion transformation. However, due to the oxygen deficiency in the main combustion zone of the furnace, the volume fraction of reducing gases represented by CO increases, which easily causes incomplete combustion and reduces boiler efficiency. In the actual low-nitrogen combustion operation of the boiler, there is an obvious contradiction between boiler efficiency and furnace NOx emissions. How to effectively balance the contradiction between the two is currently a hot topic in the research of efficient, economical and environmentally friendly operation of boilers.
[0030] For coal-fired boilers, four rows of burners and four rows of ember wind devices are arranged in a four-corner tangential circle manner. The four-corner jet flame formed by the direct current combustion technology is easy to achieve staged treatment of air and fuel. By changing the air supply mode and controlling the distribution of air volume in the furnace, the pulverized coal can be intensified in the ignition stage while ensuring that there is no excess oxygen, thus reducing NO as much as possible. X The amount of NO generated X Most of the coal powder can be reduced in the reduction zone above the main combustion zone, and the unburned coal powder is mixed with the ember wind and burned completely in the ember zone above the furnace. X Emission reduction is a necessary technological transformation route with important application value.
[0031] At present, the four-corner tangential circle arrangement combustion method based on direct current combustion technology is mainly to form an overall rotating airflow in the furnace. The rotating airflow is usually prone to uneven airflow distribution and affects the thick and thin separation effect due to the process of coal powder entering the furnace. The pressure loss generated at the integral bellows and the elbows of the pipeline for the coal powder entering the furnace may even affect the pressure and wind speed of the primary air, secondary air and ember air due to different coal quality conditions, thereby affecting the combustion and transportation process of the coal powder.
[0032] In order to solve the above technical problems, the present invention proposes the following technical solutions and corresponding embodiments.
[0033] Example 1
[0034] Combine the following Figures 1 to 6 The embodiments shown describe the technical solution of the present invention:
[0035] Reference Figures 1 to 6 As shown, the boiler graded low NO X The combustion system includes four groups of burner devices arranged at the four corners of the lower part of the furnace and four ember wind devices arranged at the four corners of the upper part of the furnace, wherein the burner devices and the ember wind devices are arranged in a four-corner tangential circle manner, and each group of burners includes 6 horizontal low-nitrogen strong entrainment pulverized coal burners, and the 6 horizontal low-nitrogen strong entrainment pulverized coal burners are divided into two groups and arranged longitudinally at one corner, wherein the 3 horizontal low-nitrogen strong entrainment pulverized coal burners of the first longitudinal group and the 3 horizontal low-nitrogen strong entrainment pulverized coal burners of the second longitudinal group are separated by a physical partition, and the 6 horizontal low-nitrogen strong entrainment pulverized coal burners are arranged longitudinally at one corner. A secondary air nozzle is respectively provided at the upper and lower positions of the device, wherein the secondary air nozzles at the upper and lower positions of the first five horizontal thin-concentration, low-nitrogen, strong entrainment pulverized coal burners are all of the first caliber, and a second caliber secondary air nozzle is provided below the lowest horizontal thin-concentration, low-nitrogen, strong entrainment pulverized coal burner, wherein the second aperture is larger than the first aperture, so that the lowest secondary air nozzle can hold the fallen unburned coal powder particles to improve the combustion efficiency. Here, it should be noted that the lowest layer can be a horizontal thin-concentration, low-nitrogen, strong entrainment pulverized coal burner and can be an oil gun layer, which includes a micro-oil gun for realizing ignition in the furnace.
[0036] That is to say, reference Figure 2As shown, in the arrangement of each group of burners, a second-caliber No. 1 secondary air nozzle 1 is provided below the sixth burner 2 at the bottom, a second-caliber No. 2 secondary air nozzle 3 is provided above the sixth burner 2, a fifth burner is provided above the second secondary air nozzle 3, a first-caliber No. 3 secondary air nozzle 4 is provided above the fifth burner, a fourth burner 5 is provided above the third secondary air nozzle 4, a first-caliber No. 4 secondary air nozzle 6 is provided above the fourth burner 5, and a first group of longitudinal burners is provided above the fourth secondary air nozzle 6. A physical partition between the burner and the second group of longitudinal burners is provided, and a No. 5 secondary air nozzle 7 of the first caliber is provided above the physical partition, and a third burner is provided above the No. 5 secondary air nozzle 7, and a No. 6 secondary air nozzle 8 of the first caliber is provided above the third burner, and a second burner is provided above the No. 6 secondary air nozzle 8, and a No. 7 secondary air nozzle 9 of the first caliber is provided above the second burner, and a first burner located at the top is provided above the No. 7 secondary air nozzle 9, and a No. 8 secondary air nozzle 10 of the first caliber is provided above the first burner. At the same time, in the four groups of burner devices, the four uppermost secondary air nozzles located at the four corners are designed for hedging.
[0037] In the embodiment of the present application, for each group of burner devices mentioned above, the No. 1 secondary air nozzle, the sixth burner and the nozzles on the layer where the fifth burner are located in each corner do not participate in the swing and are fixed, and the layer where the No. 1 secondary air nozzle is located needs to keep the nozzle in a horizontal position; the remaining nozzles are set to participate in the swing, and the swing range is within the range of ±15°. A swing connecting rod is installed corresponding to each swinging layer and butt-welded with the original connecting rod. For the nozzles that need to be adjusted, they are adjusted through the adjusting nut on the connecting rod. Among them, when adjusting the vertical swing of the secondary air port, first adjust the outer cylinder of the boiler to make it swing to the zero scale, and after the nozzle in the furnace is fixed to a horizontal position, cut the swing connecting rod according to the actual size of the new connecting rod. Among them, the secondary air nozzles are provided with guide plates that are cross-distributed longitudinally and transversely.
[0038] In the embodiment of the present application, a left secondary air wind box is provided at the lower part of the left wall of the furnace, and a left ember air wind box is provided at the upper part of the left wall of the furnace, wherein the second angle burner device and the third angle burner device are simultaneously connected to the left secondary air wind box through the first guide air duct, and the second angle ember air device and the second ember air device are simultaneously connected to the left ember air wind box through the second guide air duct; a right secondary air wind box is provided at the lower part of the right wall of the furnace, and a right ember air wind box is provided at the upper part of the right wall of the furnace, the first angle burner device and the fourth angle burner device are simultaneously connected to the right secondary air wind box through the third guide air duct, and the first angle ember air device and the fourth angle ember air device are simultaneously connected to the right ember air wind box through the fourth guide air duct; wherein, reference Figure 1As shown, the left wall and the right wall are located on opposite sides of the box body of the furnace, the No. 2 corner burner device and the No. 3 corner burner device are respectively located at the No. 2 corner 11 and the No. 3 corner 12 corresponding to the left wall, the No. 2 corner ember wind device is located at the No. 2 corner 11 (i.e. the lower left corner / first corner), and the No. 3 corner ember wind device is located at the No. 3 corner 12 (i.e. the upper left corner / second corner); the No. 1 corner burner device and the No. 4 corner burner device are respectively located at the No. 1 corner 13 and the No. 4 corner 14 corresponding to the right wall, the No. 1 corner ember wind device is located at the No. 1 corner 13 (i.e. the lower right corner / third corner), and the No. 4 corner ember wind device is located at the No. 4 corner 14 (i.e. the upper right corner / fourth corner).
[0039] Here, reference Figure 1 As shown, the left secondary air box and the left ember air box are connected to the blower outlet through the first air duct and the second air duct respectively (the left secondary air box and the left ember air box are located on one side of the furnace, as shown in FIG. Figure 1 The first air guide duct and the second air guide duct have the same structure. Figure 1 Only the top view structure of the second guide air duct connected to the second corner ember wind device and the third corner ember wind device can be seen from the top view); the right secondary air box and the right ember wind box are connected to the outlet of the blower through the third air duct and the fourth air duct respectively, and the third air duct and the fourth air duct are respectively led out from the output horizontal pipe section of the blower outlet on one side of the furnace from the top and bottom (reference Figure 1 The right side of Figure 1 The top-down angle in the figure can only show the top-down structure of a single fourth guide air duct connected to the first-horn ember burning wind device and the fourth-horn ember burning wind device), the first air duct and the second air duct are led out from the output horizontal pipe section of the blower outlet on the other side of the furnace from the top and bottom respectively, here, the first air duct includes a part of the left-side output horizontal pipe section and the first guide air duct, the second air duct includes a part of the left-side output horizontal pipe section and the second guide air duct, the third air duct includes a part of the right-side output horizontal pipe section and the third guide air duct, and the fourth air duct includes a part of the right-side output pipe and the fourth guide air duct. Among them, the first guide air duct, the second guide air duct, the third guide air duct and the fourth guide air duct are duct structures of the same structure, refer to Figure 3 , Figure 4 As shown. Through software simulation test, the distribution characteristics of the bellows and air duct are good, and there is no phenomenon that the wind speed of a certain nozzle is too high or too low due to different resistance.
[0040] As a feasible implementation method, the left secondary air bellows in the embodiment of the present application can also be in the form of an angle bellows, which is located at the lower part of the left wall of the furnace, and the number two angle burner device and the number three angle burner device are integrally contained in the angle bellows, so that the secondary air can directly pass into the number two angle burner device and the number three angle burner device after being introduced into the left secondary air bellows. Among them, the left secondary air bellows is connected to the outlet of the blower through the first air duct, and the secondary air is introduced into the left secondary air bellows. The right secondary air bellows in the embodiment of the present application can adopt the same form as above, which will not be repeated here.
[0041] In the embodiment of the present application, the center elevations of the left and right ember wind wind boxes are both 34-35.2m; the center elevation of the output horizontal pipe section is 31.5m. In a feasible implementation, booster fans are provided at the ends of the air ducts corresponding to the inlets of the left and right ember wind wind boxes. In the embodiment of the present application, the ember wind does not affect the secondary air supply in the main combustion area after it is led out. On the one hand, this is because the secondary air volume in the main combustion area is reduced during the formulation of the burner plan. On the other hand, this is because the flow rate in the entire wind box air duct is relatively low, forming a constant pressure container as a whole. The differential pressure between the wind box and the furnace is completely converted into kinetic energy after overcoming the resistance of the SOFA air duct.
[0042] In the embodiment of the present application, the number of ember wind nozzles of the ember wind device 11 is 4, and the 4 ember wind nozzles are arranged longitudinally. In this way, a total of 18 layers of nozzles are arranged in each corner, including 6 layers of burners, 8 layers of secondary air nozzles and 4 layers of ember wind nozzles. Figure 2 As shown, the separated combustion air SOFA1-SOFA4 refers to 4 combustion air nozzles, and the AA layer to the FF layer are 14 layers corresponding to the burner device, including 6 layers of burners and 8 layers of secondary air nozzles, wherein the burner layer is a single letter, such as A, B, etc., and the secondary air nozzle is a combination of letters, such as AA, AB, BC, etc.
[0043] In the embodiment of the present application, each group of the burner device includes 6 horizontal thick and thin burners (corresponding to the horizontal thick and thin low nitrogen strong entrainment pulverized coal burners in the embodiment of the present application), and a vertical blunt body is provided between the thick coal powder room and the thin coal powder room of each of the horizontal thick and thin burners, so that a certain angle is formed between the thick and thin primary air, which can play the role of entraining high-temperature flue gas, delay the mixing of the thick and thin primary air, and at the same time be conducive to ignition and stable combustion, ensure horizontal thick and thin combustion, and reduce the generation of NOx. Under low nitrogen combustion conditions, the main burner area is in a reducing atmosphere, and furnace slagging and high-temperature corrosion are more likely to occur. Compared with vertical up and down thick and thin, horizontal thick and thin is more beneficial to preventing furnace slagging and high-temperature corrosion, thereby improving boiler safety.
[0044] In the embodiment of the present application, horizontal stable combustion teeth are arranged between the concentrated coal powder to enhance the high-temperature smoke entrainment capacity near the nozzle and the residence time of the coal powder airflow near the nozzle, retaining the characteristics that are conducive to the ignition and stable combustion of coal powder, and more conducive to reducing the carbon content of fly ash and large slag, and improving combustion efficiency. The outlet blunt plate baffle of each horizontal concentrated and diluted burner is changed from the original "+" type to the "l" type to ensure that the rigidity of the coal powder jet is enhanced under the same primary wind speed.
[0045] In the examples of this application, refer to Figure 5 As shown, a block is provided inside the inlet end of each of the horizontal thick-lean burners of the No. 2 angle burner device and the No. 3 angle burner device, and the block is located at the outer corner of the airflow flowing through the inlet section, and the first block corresponding to the upper horizontal thick-lean burner of the No. 2 angle burner device is located at the upper right of the corresponding inlet section (from the direction of the furnace interior), and the second block corresponding to the lower horizontal thick-lean burner of the No. 2 angle burner device is located at the lower left of the corresponding inlet section (from the direction of the furnace interior). In the embodiment of the present application, the area of the third block corresponding to the horizontal thick-lean burner (such as the third burner and the fourth burner) in the middle position of the No. 2 angle burner device is smaller than the area of the first block / the second block.
[0046] Based on the aforementioned embodiments, the present application is applicable to the combustion method of the above-mentioned combustion system as follows: when in use, the burner devices located at the four corners of the furnace are turned on at the same time, taking corner No. 2 as an example, the gas at the outlet of the blower is led out from top and bottom through the output horizontal pipe section to the left-side burnout air box located at the upper left part of the furnace and the left-side secondary air box located at the lower left part of the furnace, and then the secondary air is led from the left-side secondary air box through the guide air duct to the secondary air nozzle located at the upper left corner of the furnace, and is injected into the furnace through multiple secondary air nozzles. After the coal powder and primary air are introduced into the furnace through multiple burners, the secondary air is taken into the furnace based on the 8 secondary air nozzles arranged longitudinally, and the burner device is started; then after the combustion is stable, the burnout air is injected into the furnace through the left-side burnout air box that has been raised to a higher height, to complete the graded combustion treatment process in the furnace.
[0047] The present disclosure exemplarily describes the working process of the boiler in the embodiment of the present application as follows:
[0048] The primary fans are started so that the primary fans located around the furnace spray the primary air carrying the pulverized coal through the burner to the main combustion zone in the furnace, thereby forming a pulverized coal ring in the furnace that is close to or similar to the first imaginary tangential circle. Figure 6 As shown; and start the burner to ignite the pulverized coal in the furnace to make the boiler run; at this time, due to the small amount of air, the combustion in the main combustion zone is in an oxygen-deficient state, forming a reducing atmosphere. In this atmosphere, the nitrogen in the fuel is not easily oxidized into nitrogen oxides, which inhibits the initial generation of nitrogen oxides;
[0049] Start the secondary fan, and the secondary air after air preheating is sprayed into the furnace through the secondary air nozzle arranged in the burner device to form a reduction zone, and gradually increase the supply of secondary air; alternatively, start the secondary fan at the same time as starting the primary fan. The present disclosure does not specifically limit the order of starting the primary fan and the secondary fan.
[0050] After the combustion in the main combustion zone is basically stable, the ember wind device is started to spray the ember wind from the ember wind box through the ember wind nozzle into the furnace, providing sufficient oxygen for the incompletely burned pulverized coal to ensure complete combustion of the fuel.
[0051] The present application provides a low NO X The boiler staged combustion system with advanced technology is designed. By setting separate ember air wind boxes and secondary air wind boxes on the outer walls on the opposite sides of the furnace, the secondary air system and the ember air system are respectively provided with conveying pipelines. The air ducts and wind boxes are fully considered, so that the air flow rate in each air duct and wind box is relatively low. Based on the multi-dimensional digital simulation, the air flow distribution characteristics can be improved to make the temperature distribution in the furnace more uniform, the combustion cutting circle effect is better, and the loss of pulverized coal and primary air, secondary air and ember air in the combustion and transportation process is reduced, and NO X Low emissions and improved coal powder combustion efficiency.
[0052] The above embodiments are only used to illustrate the technical solution of the present application, but not to limit it. The present application is not limited to the exact structure described above and illustrated in the accompanying drawings, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, various changes and modifications made without departing from the concept of the present application should be deemed to belong to the protection scope of the present application.
[0053] In the several embodiments provided in the present application, it should be understood that the disclosed systems, modules and methods can be implemented in other ways. For example, the module embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, modules or units, which can be electrical, mechanical or other forms.
[0054] The above embodiments are only used to illustrate the technical solution of the present application, but not to limit it. The present application is not limited to the exact structure described above and illustrated in the accompanying drawings, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, various changes and modifications made without departing from the concept of the present application should be deemed to belong to the protection scope of the present application.
Claims
1. A boiler graded low NO X A combustion system, characterized in that It comprises four groups of burner devices respectively arranged at the four corners of the lower part of the furnace and ember wind devices arranged at the four corners of the upper part of the furnace, wherein each group of the burner devices comprises at least two burners and at least three layers of secondary air nozzles, and each of the ember wind devices comprises at least one layer of ember wind nozzles; a left secondary air wind box is arranged at the lower part of the left wall of the furnace, and a left ember wind wind box is arranged at the upper part of the left wall of the furnace, the second corner burner device and the third corner burner device of the four groups of burner devices are connected to the left secondary air wind box at the same time, and the second corner ember wind device and the third corner ember wind device of the four corner ember wind devices are connected to the left ember wind wind box at the same time; a right secondary air wind box is arranged at the lower part of the right wall of the furnace, and a right ember wind wind box is arranged at the upper part of the right wall of the furnace, The first-corner burner device and the fourth-corner burner device in the group of burner devices are connected to the right-side secondary air wind box at the same time, and the first-corner burner wind device and the fourth-corner burner wind device in the four-corner burner wind devices are connected to the right-side burner wind box at the same time; wherein, the left wall and the right wall are located at the relatively outer sides of the box body of the furnace, and the second-corner burner device and the third-corner burner device are respectively located at the second corner and the third corner corresponding to the left wall, and the second-corner burner wind device is located at the second corner, and the third-corner burner wind device is located at the third corner; the first-corner burner device and the fourth-corner burner device are respectively located at the first corner and the fourth corner corresponding to the right wall, and the first-corner burner wind device is located at the first corner, and the fourth-corner burner wind device is located at the fourth corner; The left secondary air box and the left ember air box are connected to the blower outlet through the first air duct and the second air duct respectively; the right secondary air box and the right ember air box are connected to the blower outlet through the third air duct and the fourth air duct respectively.
2. A boiler graded low NOx according to claim 1 X A combustion system, characterized in that The first air duct and the second air duct are led out from the output horizontal pipe section of the blower outlet from the top and bottom respectively; Based on the first guide air duct, the airflow in the left secondary air box is led out from the left and right to the second angle burner device and the third angle burner device respectively, so as to form the secondary air in the second angle burner device and the third angle burner device; Based on the second guide air duct, the airflow in the left ember wind box is led out from the left and right to the second-angle ember wind device and the third-angle ember wind device respectively, forming the ember wind at the second-angle ember wind device and the third-angle ember wind device.
3. A boiler graded low NOx according to claim 2 X A combustion system, characterized in that Each group of the burner devices includes several horizontal thick-lean burners. A block is provided inside the inlet end of each of the horizontal thick-lean burners of the second-angle burner device and the third-angle burner device. The block is located at the outer corner of the airflow passing through the inlet section.
4. A boiler graded low NOx according to claim 3 X A combustion system, characterized in that The first stopper corresponding to the horizontal thick-lean burner at the upper part of the No. 2 angle burner device is located at the upper right of the corresponding inlet section; the second stopper corresponding to the horizontal thick-lean burner at the lower part of the No. 2 angle burner device is located at the lower left of the corresponding inlet section; the area of the third stopper corresponding to the horizontal thick-lean burner at the middle position of the No. 2 angle burner device is smaller than the area of the first stopper / the second stopper.
5. A boiler graded low NOx according to claim 2 X A combustion system, characterized in that The center elevation of the left ember wind bellows is 34-35.2m; the center elevation of the output horizontal pipe section is 31.5m.
6. A boiler graded low NOx according to claim 1 X A combustion system, characterized in that The at least two layers of secondary air nozzles include a first secondary air nozzle and a second secondary air nozzle, the first secondary air nozzle is a fixed nozzle, and the second secondary air nozzle is a swing nozzle.
7. A boiler graded low NOx according to claim 6 X A combustion system, characterized in that The at least two layers of secondary air nozzles include eight layers of secondary air nozzles arranged longitudinally, at least one layer of secondary air nozzles in the bottom layer is a fixed nozzle, and the seven layers of secondary air nozzles in the upper layer are swing nozzles; the swing amplitude of the swing nozzle is ±15°.
8. A boiler graded low NOx according to claim 1 X A combustion system, characterized in that The ember wind device comprises four layers of ember wind nozzles arranged longitudinally.
9. A boiler graded low NOx according to claim 3 X A combustion system, characterized in that A vertical blunt body is provided between the rich coal powder room and the light coal powder room of each of the horizontal rich-lean burners; horizontal stabilizing teeth are arranged in the rich coal powder room; and the outlet blunt plate of each of the horizontal rich-lean burners is vertical.
10. A boiler graded low NOx according to any one of claims 1 to 9 X A combustion system, characterized in that A booster fan is provided at the end of the air duct corresponding to the inlet of the ember wind box.