Low-power pulverized coal burner of W flame boiler and coal pulverizing system

Abstract

The invention belongs to the technical field of power station boiler pulverized coal combustion power generation, and particularly relates to a W flame boiler low-power pulverized coal burner and a coal pulverizing system. According to the technical scheme, the W flame boiler low-power pulverized coal burner and the coal pulverizing system comprise a coal mill and a low-power burner installed on a hearth, and a distribution unit is connected between the coal mill and the low-power burner; an exhaust gas separation unit is connected between an inlet of the low-power combustor and a water cooling wall of the hearth, a combustor inlet elbow and a pulverized coal concentrator are arranged in the low-power combustor, and a V-shaped bluff body of a pulverized coal nozzle is arranged at an outlet of the low-power combustor. The invention provides a W flame boiler low-power pulverized coal burner and a coal pulverizing system. The W flame boiler low-power pulverized coal burner and the coal pulverizing system have extremely wide coal type adaptability and excellent wide load adjusting capacity, low-nitrogen emission capacity and anti-coking capacity.

Description

Technical Field

[0001] The invention belongs to the technical field of power station boiler pulverized coal combustion power generation, and in particular relates to a W-flame boiler low-power pulverized coal burner and a pulverizing system. Background Art

[0002] The thermal power generating units in the new power system must have the ability of flexible peak regulation, high efficiency and low pollutant emission, and the pulverized coal combustion equipment, as one of the core equipment of the thermal power units, must have better ignition and stable combustion capabilities, especially for W-flame boilers burning low-volatile coal, which face a more severe test of wide load regulation capability.

[0003] Conventionally, the thermal power of a single burner of a W-flame boiler burning low-volatile coal is about 40 to 60MW. The thermal power load regulation capability of a single burner is poor. At low load, the combustion heat load is poorly uneven in the width direction of the boiler, which can easily lead to cracking of the water-cooled wall. All of the above factors make the minimum stable combustion load of a W-flame boiler unit burning low-volatile coal greater than 40% without adding oil. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the purpose of the present invention is to provide a W-flame boiler low-power pulverized coal burner and pulverizing system, which has extremely wide coal type adaptability, extremely wide load regulation capability, low nitrogen emission capability and anti-coking capability.

[0005] The technical solution adopted by the present invention is:

[0006] A W-flame boiler low-power pulverized coal burner and pulverizing system, comprising a coal mill and a low-power burner installed on a furnace, wherein a distribution unit is connected between the coal mill and the low-power burner; an exhaust gas separation unit is connected between the inlet of the low-power burner and the water-cooled wall of the furnace, a burner inlet elbow and a pulverized coal concentrator are arranged in the low-power burner, and a pulverized coal nozzle V-shaped blunt body is arranged at the outlet of the low-power burner.

[0007] According to the load regulation requirements, the present invention can operate with a single burner or simultaneously operate two low-power burners in the form of a burner group. The thermal power of a single low-power pulverized coal burner is about 18-25MW, and the thermal power of each burner group is about 36-50MW. The single low-power burner and the burner group have strong ignition and stable combustion capabilities. Under low-load conditions, there is no need to adjust the output of a single burner, and stable combustion of the entire furnace can be achieved by only adjusting the number of burners in operation. For low-volatile coal, the lowest non-oil stable combustion load of <25% can be achieved, which greatly improves the wide load regulation capability of the low-volatile coal-fired boiler unit.

[0008] The present invention organically combines the exhaust gas separation unit, the burner inlet elbow, the wedge-shaped large blunt body coal powder concentrator, and the thick and thin separation coal powder nozzle V-shaped blunt body to perform four-stage concentration of air powder, and obtain an ultra-high concentration of coal powder airflow at the burner outlet end, which is beneficial to its ignition organization, stable combustion and low nitrogen emission.

[0009] When the unit load changes, the present invention is coupled with the W-flame boiler wide load adjustment system. It can achieve uniform distribution of heat load in the entire furnace and stable combustion by only cutting off the coal mill or part of the coal mill's pulverized coal pipes and their corresponding burners without adjusting the output of a single pulverized coal burner, and has the ability to quickly respond to changes in the boiler unit load.

[0010] As a preferred embodiment of the present invention, low-power burners are provided on both sides of the front and rear of the furnace, and the distribution units are respectively connected to the low-power burners on both sides. The two low-power burners of the present invention are combined back to back to form a burner group. Under high-load conditions, the center of the burner group is high-concentration coal powder, and the two sides are light coal powder airflows. Peripheral wind is set outside the light coal powder airflow. On the one hand, the formation of wind-enclosed powder is conducive to ignition and stable combustion. On the other hand, the momentum of the primary wind powder is increased to increase the downward stroke of the coal powder and the residence time of the coal powder in the lower furnace, which greatly improves the stable combustion and burnout ability of the coal powder. The increase in the primary wind powder stroke can also ensure the flame fullness of the lower furnace, increase the heat absorption of the water-cooled wall, thereby reducing the temperature in the furnace, which is beneficial to control NO X generate.

[0011] As a preferred embodiment of the present invention, the major diameter direction of the burner inlet elbow is consistent with the concentrated side direction of the pulverized coal concentrator.

[0012] As a preferred embodiment of the present invention, the exhaust gas unit includes an exhaust gas separation device, which is installed at the inlet of the low-power burner. The exhaust gas separation device is connected to an exhaust gas pipeline, on which an exhaust gas regulating valve is provided, and the other end of the exhaust gas pipeline is connected to the exhaust gas nozzle.

[0013] As a preferred solution of the present invention, a peripheral wind nozzle is arranged on the side of the low-power burner, and the peripheral wind nozzle is located close to the outlet of the low-power burner.

[0014] As a preferred solution of the present invention, the outlet of the low-power burner is further provided with a flame stabilizing tooth.

[0015] As a preferred solution of the present invention, a square-circle section is provided on the side of the burner inlet elbow close to the coal powder concentrator.

[0016] As a preferred embodiment of the present invention, the distribution unit includes a large pulverized coal pipeline, on which a pulverizer outlet gate is provided, the outlet of the large pulverized coal pipeline is connected to a pulverized coal distributor, and the other end of the pulverized coal distributor is connected to a low-power burner through a small pulverized coal pipeline.

[0017] As a preferred solution of the present invention, the pulverized coal distributor is connected with an adjustable shrinkage hole and a pulverized coal online monitoring device.

[0018] As a preferred solution of the present invention, the inlet end of the low-power burner is connected with a burner front plug-in door.

[0019] The beneficial effects of the present invention are:

[0020] 1. According to the load regulation requirements, the present invention can operate with a single burner or simultaneously operate two low-power burners in the form of a burner group. The thermal power of a single low-power pulverized coal burner is about 18-25MW, and the thermal power of each burner group is about 36-50MW. The single low-power burner and the burner group have strong ignition and stable combustion capabilities. Under low-load conditions, there is no need to adjust the output of a single burner, and the stable combustion of the entire furnace can be achieved by only adjusting the number of burners in operation. For low-volatile coal, the lowest stable combustion load without oil addition can be achieved at <25%, which greatly improves the wide load regulation capability of low-volatile coal-fired boiler units.

[0021] 2. The present invention organically combines the exhaust gas separation unit, the burner inlet elbow, the wedge-shaped large blunt body coal powder concentrator, and the V-shaped blunt body of the coal powder nozzle for thick and thin separation to carry out four-stage concentration of the air powder, and obtain an ultra-high concentration of coal powder airflow at the burner outlet, which is beneficial to its ignition organization, stable combustion, and low nitrogen emission.

[0022] 3. When the unit load changes, the present invention is coupled with the W-flame boiler wide load adjustment system. It can achieve uniform distribution of heat load in the entire furnace and stable combustion by only cutting off the coal mill or part of the coal mill's pulverized coal pipes and their corresponding burners without adjusting the output of a single pulverized coal burner, and has the ability to quickly respond to changes in the boiler unit load.

[0023] 4. The two low-power burners of the present invention are back-to-back combined to form a burner group. Under high-load conditions, the center of the burner group is high-concentration coal powder, and the two sides are light coal powder airflows. A peripheral wind is arranged outside the light coal powder airflow. On the one hand, the formation of wind-enclosed powder is conducive to ignition and stable combustion. On the other hand, the momentum of the primary wind powder is increased to increase the downward stroke of the coal powder and the residence time of the coal powder in the lower furnace, which greatly improves the stable combustion and burnout capabilities of the coal powder; the increase in the primary wind powder stroke can also ensure the flame fullness of the lower furnace, increase the heat absorption of the water-cooled wall, thereby reducing the temperature in the furnace, which is conducive to controlling NO X generate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the present invention;

[0025] Figure 2 It is a structural diagram of a low-power burner;

[0026] Figure 3It is a schematic diagram of the four-stage concentration principle.

[0027] In the figure: 1- coal mill; 2- large pulverized coal pipeline; 3- pulverized coal outlet plug door; 4- pulverized coal distributor; 5- adjustable shrinkage hole; 6- pulverized coal online monitoring device; 7- small pulverized coal pipeline; 8- burner front plug door; 9- low-power burner; 10- furnace; 11- exhaust gas nozzle; 12- exhaust gas pipeline; 13- exhaust gas separation device; 14- exhaust gas regulating valve; 15- burner inlet elbow; 16- square and round section; 17- pulverized coal concentrator; 18- perimeter wind nozzle; 19- pulverized coal nozzle V-shaped blunt body; 20- flame stabilizing tooth. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0030] like Figure 1 to Figure 3 As shown, the W-flame boiler low-power pulverized coal burner and pulverizing system of this embodiment includes a coal mill 1 and a low-power burner 9 installed on a furnace 10, a distribution unit is connected between the coal mill 1 and the low-power burner 9, and the distribution unit provides uniform air and pulverized coal for each low-power pulverized coal burner; an exhaust gas separation unit is connected between the inlet of the low-power burner 9 and the water-cooled wall of the furnace 10, a burner inlet elbow 15 and a pulverized coal concentrator 17 are arranged in the low-power burner 9, and a pulverized coal nozzle V-shaped blunt body 19 is arranged at the outlet of the low-power burner 9.

[0031] The major diameter direction of the burner inlet elbow 15 is consistent with the concentrated side direction of the pulverized coal concentrator 17 .

[0032] Specifically, the exhaust gas unit includes an exhaust gas separation device 13, which is installed at the inlet of the low-power burner 9. The exhaust gas separation device 13 is connected to an exhaust gas pipeline 12, on which an exhaust gas regulating valve 14 is provided. The other end of the exhaust gas pipeline 12 is connected to the exhaust gas nozzle 11.

[0033] Furthermore, the side of the low-power burner 9 is provided with a peripheral wind nozzle 18, and the peripheral wind nozzle 18 is located near the outlet of the low-power burner 9. The outlet of the low-power burner 9 is also provided with a flame stabilizing tooth 20. The side of the burner inlet elbow 15 close to the coal powder concentrator 17 is provided with a square section 16. The inlet end of the low-power burner 9 is connected to the burner front plug-in plate door 8.

[0034] Specifically, the distribution unit includes a large pulverized coal pipeline 2, on which a pulverizer outlet gate 3 is provided, and the outlet of the large pulverized coal pipeline 2 is connected to a pulverized coal distributor 4, and the other end of the pulverized coal distributor 4 is connected to a low-power burner 9 through a small pulverized coal pipeline 7. The pulverized coal distributor 4 is connected to an adjustable shrinkage hole 5 and a pulverized coal online monitoring device 6.

[0035] According to the load regulation requirements, the present invention can operate with a single burner or simultaneously operate two low-power burners 9 in the form of a burner group. The thermal power of a single low-power pulverized coal burner is about 18-25MW, and the thermal power of each burner group is about 36-50MW. The single low-power burner 9 and the burner group have strong ignition and stable combustion capabilities. Under low-load conditions, there is no need to adjust the output of a single burner, and stable combustion of the entire furnace 10 can be achieved by only adjusting the number of burners in operation. For low-volatile coal, the lowest non-oil stable combustion load of <25% can be achieved, which greatly improves the wide load regulation capability of the low-volatile coal-fired boiler unit.

[0036] The present invention organically combines the exhaust gas separation unit, the burner inlet elbow 15, the wedge-shaped large blunt body coal powder concentrator 17, and the thick and thin separation coal powder nozzle V-shaped blunt body 19 to perform four-stage concentration of air powder, and obtain an ultra-high concentration of coal powder airflow at the burner outlet end, which is beneficial to its ignition organization, stable combustion and low nitrogen emission.

[0037] When the unit load changes, the present invention is coupled with the W-flame boiler wide load adjustment system. It can achieve uniform distribution of heat load and stable combustion in the entire furnace 10 by only shutting down the coal mill 1 or part of the pulverized coal pipes of the coal mill 1 and their corresponding burners without adjusting the output of a single pulverized coal burner, and has the ability to quickly respond to changes in the boiler unit load.

[0038] In some embodiments, low-power burners 9 are provided on both the front and rear sides of the furnace 10, and the distribution units are respectively connected to the low-power burners 9 on both sides. The two low-power burners 9 of the present invention are combined back to back to form a burner group. Under high-load conditions, the center of the burner group is high-concentration coal powder, and the two sides are light coal powder airflows. Peripheral wind is set outside the light coal powder airflow. On the one hand, the formation of wind-enclosed powder is conducive to ignition and stable combustion. On the other hand, the momentum of the primary wind powder is increased to increase the downward stroke of the coal powder and the residence time of the coal powder in the lower furnace 10, which greatly improves the stable combustion and burnout ability of the coal powder; the increase of the primary wind powder stroke can also ensure the flame fullness of the lower furnace 10, increase the heat absorption of the water-cooled wall, thereby reducing the temperature in the furnace, which is conducive to controlling NO X generate.

[0039] The present invention is not limited to the above-mentioned optional implementation modes. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that fall within the scope defined by the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A low-power pulverized coal burner and pulverizing system for a W-flame boiler, characterized in that: The invention comprises a coal mill (1) and a low-power burner (9) installed on a furnace (10); a distribution unit is connected between the coal mill (1) and the low-power burner (9); an exhaust gas separation unit is connected between the inlet of the low-power burner (9) and the water-cooled wall of the furnace (10); a burner inlet elbow (15) and a coal powder concentrator (17) are arranged in the low-power burner (9); and a coal powder nozzle V-shaped blunt body (19) is arranged at the outlet of the low-power burner (9).

2. A W-flame boiler low-power pulverized coal burner and pulverizing system according to claim 1, characterized in that: Low-power burners (9) are arranged on both the front and rear sides of the furnace (10), and the distribution units are respectively connected to the low-power burners (9) on both sides.

3. A W-flame boiler low-power pulverized coal burner and pulverizing system according to claim 1, characterized in that: The major diameter direction of the burner inlet elbow (15) is consistent with the concentrated side direction of the pulverized coal concentrator (17).

4. A W-flame boiler low-power pulverized coal burner and pulverizing system according to claim 1, characterized in that: The exhaust gas unit comprises an exhaust gas separation device (13), which is installed at the inlet of the low-power burner (9), the exhaust gas separation device (13) is connected to an exhaust gas pipeline (12), an exhaust gas regulating valve (14) is arranged on the exhaust gas pipeline (12), and the other end of the exhaust gas pipeline (12) is connected to the exhaust gas nozzle (11).

5. A W-flame boiler low-power pulverized coal burner and pulverizing system according to claim 1, characterized in that: A peripheral wind nozzle (18) is arranged on the side of the low-power burner (9), and the peripheral wind nozzle (18) is located close to the outlet of the low-power burner (9).

6. A W-flame boiler low-power pulverized coal burner and pulverizing system according to claim 1, characterized in that: The outlet of the low-power burner (9) is also provided with a flame stabilizing tooth (20).

7. A W-flame boiler low-power pulverized coal burner and pulverizing system according to claim 1, characterized in that: A square section (16) is provided on one side of the burner inlet elbow (15) close to the coal powder concentrator (17).

8. A W-flame boiler low-power pulverized coal burner and pulverizing system according to claim 1, characterized in that: The distribution unit comprises a large pulverized coal pipeline (2), on which a coal mill outlet gate (3) is arranged, the outlet of the large pulverized coal pipeline (2) is connected to a pulverized coal distributor (4), and the other end of the pulverized coal distributor (4) is connected to a low-power burner (9) via a small pulverized coal pipeline (7).

9. A W-flame boiler low-power pulverized coal burner and pulverizing system according to claim 8, characterized in that: The pulverized coal distributor (4) is connected to an adjustable shrinkage hole (5) and a pulverized coal online monitoring device (6).

10. A W-flame boiler low-power pulverized coal burner and pulverizing system according to any one of claims 1 to 9, characterized in that: The inlet end of the low-power burner (9) is connected to a burner front plug-in door (8).

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