Low-NOx pulverized coal burner for boiler of thermal power plant and burning method of low-NOx pulverized coal burner

Abstract

The invention relates to the technical field of thermal power generation equipment, in particular to a thermal power plant boiler low-NOx pulverized coal burner and a burning method thereof.The thermal power plant boiler low-NOx pulverized coal burner comprises an air supply mechanism, an air supply device is arranged on one side of the air inlet end of the air supply mechanism, a burning chamber is arranged at the air outlet end of the air supply mechanism, and an ignition gun penetrating through the air inlet end and the air outlet end is arranged in the air supply mechanism; a combustion-supporting gas conveying mechanism is further communicated between the combustion chamber and the air outlet end and comprises a combustion-supporting gas sleeve and a flow dividing sleeve, the flow dividing sleeve is communicated with the air outlet end, the combustion chamber is located in the flow dividing sleeve, a flow dividing plate is arranged between the flow dividing sleeve and the combustion chamber, and combustion-supporting gas nozzles and rotational flow channels which are staggered are arranged on the flow dividing plate. The combustion-supporting gas sleeve is arranged on the outer side of the flow dividing sleeve in a sleeving mode, a combustion-supporting gas inlet pipe is arranged on the bottom side of the combustion-supporting gas sleeve, and a combustion-supporting gas spraying pipe is arranged on the inner side of the combustion-supporting gas sleeve, extends into the flow dividing sleeve and is located on one side of the combustion-supporting gas nozzle. By optimizing the structural design and combustion process control of the combustor, generation and emission of NOx are effectively reduced, meanwhile, the combustion efficiency is improved, the adaptability to different coal types is enhanced, and the equipment cost and the maintenance difficulty are reduced.

Description

Technical Field

[0001] This invention relates to the field of thermal power generation equipment technology, and in particular to a low NO₂ level boiler for thermal power plants. x Pulverized coal burners and their combustion methods. Background Technology

[0002] In the thermal power generation industry, the performance of the boiler combustion system plays a crucial role in power generation efficiency and environmental performance indicators. Traditional pulverized coal burners produce large amounts of nitrogen oxides (NOx) during combustion. x NO x NO is one of the major air pollutants, leading to environmental problems such as acid rain and photochemical smog, causing serious harm to the ecological environment and human health. With increasingly stringent environmental regulations, reducing NO emissions during the combustion process in thermal power plant boilers is becoming increasingly important. x Emissions have become a critical issue that urgently needs to be addressed within the industry.

[0003] Currently, there are many ways to reduce nitrogen oxides. For example, improving the burner structure can shorten the residence time of gas in the high-temperature zone and reduce the maximum flame temperature, thereby reducing the nitrogen oxide concentration. Another method is to introduce the air required for combustion into the combustion chamber in stages, creating "fuel-rich" and "fuel-lean" zones to reduce peak combustion temperature and oxygen concentration, thus inhibiting nitrogen oxide formation. Additionally, flue gas recirculation technology can be used to introduce a portion of the boiler exhaust (mainly composed of inert gases such as N2, CO2, and H2O) into the combustion zone, diluting the oxygen concentration and reducing the flame temperature, thus inhibiting nitrogen oxide formation.

[0004] Currently, although various technologies and equipment for reducing NOx emissions exist on the market, they generally have some problems. For example, some burners have poor adaptability to different types of coal and cannot guarantee a stable low NOx emission effect when burning pulverized coal of different qualities; some burners have complex structures, high manufacturing costs, and are difficult to maintain; and some burners, while reducing NOx emissions, lead to a decrease in combustion efficiency, increasing power generation costs.

[0005] Therefore, it is necessary to develop a method that can efficiently reduce NO x The development of pulverized coal burners and their combustion methods that can reduce emissions while ensuring combustion efficiency and stability, and that are adaptable to different coal types, simple in structure, and low in cost, is of great practical significance. Summary of the Invention

[0006] The purpose of this invention is to provide a low NO content for boilers used in thermal power plants. x Pulverized coal burners and their combustion methods effectively reduce NO through optimized burner structural design and combustion process control. x It reduces the generation and emission of pollutants, while improving combustion efficiency, enhancing adaptability to different coal types, and reducing equipment costs and maintenance difficulty.

[0007] To achieve the above objectives, the present invention provides a low NO₂ level for boilers used in thermal power plants. x A pulverized coal burner includes an air supply mechanism. An air supply device is provided on one side of the air inlet end of the air supply mechanism, and a combustion chamber is provided on the air outlet end of the air supply mechanism. An ignition gun is provided inside the air supply mechanism, penetrating both the air inlet and outlet ends. A combustion-supporting gas delivery mechanism is also connected between the combustion chamber and the air outlet end. The combustion-supporting gas delivery mechanism includes a combustion-supporting gas sleeve and a diverting sleeve. The diverting sleeve is connected to the air outlet end, and the combustion chamber is located inside the diverting sleeve. A diverting plate is provided between the diverting sleeve and the combustion chamber. The diverting plate has intersecting combustion-supporting gas nozzles and swirling channels. The combustion-supporting gas sleeve is fitted onto the outside of the diverting sleeve. A combustion-supporting gas inlet pipe is provided on the bottom side of the combustion-supporting gas sleeve, and a combustion-supporting gas nozzle is provided on the inner side of the combustion-supporting gas sleeve. The combustion-supporting gas nozzle extends into the diverting sleeve and is located on one side of the combustion-supporting gas nozzle.

[0008] Preferably, the air supply device includes a fan and an air inlet hood. The fan and the air inlet hood are symmetrically arranged on both sides of the air supply mechanism. A pulverized coal inlet is provided on the front side of the air inlet hood. A filter screen is provided at the pulverized coal inlet. A pulverized coal flow regulating valve is provided inside the filter screen. The end of the air inlet hood away from the air supply mechanism is connected to the flue gas recirculation mechanism.

[0009] Preferably, the flue gas recirculation mechanism includes a flue gas recirculation pipe, one end of which is connected to the air inlet hood via a flue gas flow regulating valve, and the other end of which is connected to the flue gas pre-processor, which is connected to the boiler exhaust port.

[0010] Preferably, the flue gas pre-processor includes a treatment chamber and a filter chamber. The filter chamber is connected to the treatment chamber through a flue gas inlet pipe. The top of the treatment chamber is connected to a flue gas duct. The treatment chamber is filled with an alkaline aqueous solution. The flue gas inlet pipe extends into the treatment chamber and is connected to an aerator. The filter chamber is connected to the boiler exhaust port. The filter chamber is filled with packing material, which includes crushed stone layers on both sides and an adsorption layer in the middle. The adsorption layer is activated carbon powder.

[0011] Preferably, an annular air cavity is formed between the flow divider sleeve and the combustion chamber, and a ventilation port communicating with the combustion chamber is provided on the inner wall of the annular air cavity.

[0012] Preferably, the swirl channel includes a pulverized coal nozzle and swirl blades, with the swirl blades obliquely connected to one side of the pulverized coal nozzle.

[0013] Preferably, the air supply mechanism includes an air supply chamber 1 and an air supply chamber 2 that are interconnected. An air flow regulating mechanism is provided between the air supply chamber 1 and the air supply chamber 2. The air supply chamber 1 is connected to the air supply device, and the air supply chamber 2 is connected to the gas-supporting delivery mechanism.

[0014] Preferably, the airflow regulating mechanism includes a V-shaped guide plate, an upper flip plate, and a lower flip plate. The V-shaped guide plate is located in the middle, and the upper and lower flip plates are symmetrically arranged on the upper and lower sides of the V-shaped guide plate. The middle part of the upper flip plate is connected to a flip rod one, and the middle part of the lower flip plate is connected to a flip rod two. One end of the flip rod one is connected to the flip rod two through a connecting rod assembly, and the other end of the flip rod one is connected to the regulating motor.

[0015] This invention also provides a combustion method for a low-NOx pulverized coal burner in a thermal power plant boiler, comprising the following steps: S1. Start the air supply device, which will initially mix the coal powder with the air during the air intake process to form a primary airflow carrying the coal powder; S2. The combustion gas enters the combustion gas sleeve through the combustion gas inlet pipe, and is then injected into the combustion chamber after being guided by the combustion gas nozzle inside the combustion gas sleeve. S3. The primary air carrying pulverized coal enters the diversion sleeve from the air outlet of the air supply mechanism, and enters the combustion chamber through the staggered swirl channels on the diversion plate, where it is fully mixed with the combustion-supporting gas. S4. Start the ignition gun to ignite the pulverized coal and begin the combustion process.

[0016] The beneficial effects of this invention are: (1) This invention uses flue gas recirculation technology to introduce some low-temperature flue gas to reduce the combustion temperature and reduce thermal NO. x The formation of NO₂ is achieved through the staged introduction of combustion-supporting fuels and primary air during the initial combustion phase, creating a low-oxygen, fuel-rich atmosphere and suppressing the generation of NO₂ in fuels. x The generation of NO. Actual testing showed that using the burner of this invention, the NO at the furnace outlet... x Emission concentrations can be stably controlled at low levels, meeting stringent environmental standards.

[0017] (2) The unique structural design of the burner of this invention, such as the swirling channel that causes the pulverized coal to swirl, increases the uniformity of mixing of pulverized coal with combustion gas and air; the setting of the annular air chamber and vent optimizes the airflow distribution in the combustion chamber, ensuring that the fuel can be fully burned. Actual operating data shows that by using the burner and combustion method of this invention, the combustion efficiency of the boiler is significantly improved, fuel consumption is effectively reduced, and the economic efficiency of power generation is improved.

[0018] (3) By setting up a coal powder flow regulating valve, an air flow regulating mechanism and a combustion gas inlet valve, the present invention can flexibly adjust the flow rate and ratio of coal powder, air and combustion gas according to the characteristics of different coal types, so that the burner can adapt to the combustion requirements of various coal types, broaden the range of coal types that thermal power plants can choose from, and reduce fuel procurement costs.

[0019] (4) The burner structure of the present invention is reasonably designed. Compared with the traditional complex burner, it has a moderate number of components and a simple connection method, which facilitates installation, maintenance and repair. At the same time, each adjustment mechanism is easy to operate and can be remotely monitored and adjusted through an automated control system, which reduces the maintenance cost of the equipment and the difficulty of manual operation.

[0020] (5) The high combustion efficiency of this invention reduces fuel consumption costs; low NO x Emissions are reduced, lowering the cost of subsequent flue gas denitrification treatment; the simple structure and easy maintenance reduce equipment maintenance costs. Overall, the burner and combustion method of this invention can effectively reduce the operating costs of thermal power plants and improve economic efficiency.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This invention relates to a low NO content boiler for thermal power plants. x Schematic diagram of a pulverized coal burner; Figure 2 This is a schematic diagram of the air supply mechanism of the present invention; Figure 3 This is a schematic diagram of the air supply chamber and the second air supply chamber of the air supply mechanism of the present invention; Figure 4 This is a three-dimensional structural schematic diagram of the gas-supporting delivery mechanism of the present invention; Figure 5 This is a side view of the gas-supporting delivery mechanism of the present invention; Figure 6 This is a cross-sectional view of the gas-supporting conveying mechanism of the present invention; Figure 7 This is a schematic diagram of the flue gas pre-processor of the present invention.

[0023] Figure label: 1. Air supply mechanism; 11. Air supply chamber one; 12. Air supply chamber two; 13. Air flow regulation mechanism; 131. V-shaped guide vane; 132. Upper tilting plate; 133. Lower tilting plate; 134. Tilting rod one; 135. Tilting rod two; 136. Linkage assembly; 137. Adjustment motor; 2. Air supply device; 21. Fan; 22. Air inlet hood; 23. Filter screen; 3. Combustion chamber; 4. Ignition gun; 5. Combustion-supporting gas delivery mechanism; 51. Combustion-supporting gas sleeve; 52. Diverting sleeve; 53. Combustion-supporting gas inlet pipe; 54. Combustion-supporting gas nozzle; 55. Annular air cavity; 56. Ventilation outlet; 6. Diverter plate; 61. Combustion-supporting nozzle; 62. Swirl channel; 621. Pulverized coal nozzle; 622. Swirl blades; 7. Flue gas recirculation mechanism; 71. Flue gas recirculation pipeline; 72. Flue gas flow regulating valve; 73. Flue gas pre-processor; 731. Processing chamber; 732. Filter chamber; 733. Flue gas inlet pipe; 734. Aerator. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0025] Example 1 Please see Figures 1 to 7 This invention provides a low NO content for boilers in thermal power plants. x A pulverized coal burner includes an air supply mechanism 1. An air supply device 2 is provided on one side of the air inlet end of the air supply mechanism 1. The air supply mechanism 1 includes two interconnected air supply chambers 11 and 12. Air supply chamber 11 is connected to the air supply device 2 and is used to receive a mixture of air and pulverized coal supplied by the air supply device 2. Air supply chamber 12 is connected to a combustion-supporting gas delivery mechanism 5 and is used to introduce combustion-supporting gas. An air flow regulating mechanism 13 is provided between air supply chamber 11 and air supply chamber 12, which can precisely regulate the flow rate and velocity of the mixed airflow entering air supply chamber 12, thereby forming primary air that meets the combustion requirements.

[0026] The airflow regulating mechanism 13 includes a V-shaped guide plate 131, an upper tilting plate 132, and a lower tilting plate 133. The V-shaped guide plate 131 is located in the middle, and the upper tilting plate 132 and the lower tilting plate 133 are symmetrically arranged on the upper and lower sides of the V-shaped guide plate 131. The middle part of the upper tilting plate 132 is connected to a tilting rod 134, and the middle part of the lower tilting plate 133 is connected to a tilting rod 135. One end of the tilting rod 134 is connected to the tilting rod 135 via a connecting rod assembly 136, and the other end is connected to a regulating motor 137. By operating the regulating motor 137, the tilting rod 134 is driven to rotate, which in turn causes the tilting rod 135 to rotate synchronously via the connecting rod assembly 136. This achieves control over the opening and closing angles of the upper tilting plate 132 and the lower tilting plate 133, and, combined with the V-shaped guide plate 131 guiding the airflow direction, achieves the purpose of regulating the airflow rate and velocity. The air outlet of the air supply mechanism 1 is connected to the combustion chamber 3 to provide primary air carrying pulverized coal for the combustion process.

[0027] The air supply device 2 includes a fan 21 and an air inlet hood 22. The fan 21 and the air inlet hood 22 are symmetrically arranged on both sides of the air supply mechanism 1. The fan 21 provides power to deliver outside air to the air inlet hood 22. A pulverized coal inlet is located on the front side of the air inlet hood 22, and a filter screen 23 is installed at the pulverized coal inlet to filter impurities and ensure the quality of the pulverized coal entering the burner. A pulverized coal flow regulating valve is located inside the filter screen 23, which can precisely adjust the amount of pulverized coal entering according to the combustion conditions, so that the pulverized coal and air are mixed in a suitable ratio. The end of the air inlet hood 22 away from the air supply mechanism 1 is connected to the flue gas recirculation mechanism 7, which can introduce a portion of the treated boiler exhaust gas into the air inlet hood 22 to mix with fresh air and pulverized coal, participating in the combustion process, thereby reducing the combustion temperature and reducing NOx formation.

[0028] The air supply mechanism 1 has a combustion chamber 3 at its outlet, which receives primary air from the air supply mechanism 1 and auxiliary combustion gas (air, O2, natural gas, hydrogen) from the auxiliary combustion gas supply mechanism 5, providing space for the full combustion of pulverized coal. The air supply mechanism 1 is equipped with an ignition gun 4 that runs through the air inlet and outlet, which can quickly generate a high-temperature flame when started, providing an initial ignition source for the subsequent combustion of pulverized coal.

[0029] A combustion chamber 3 is connected to an air outlet end by a combustion-supporting gas delivery mechanism 5. The combustion-supporting gas delivery mechanism 5 includes a combustion-supporting gas sleeve 51 and a diversion sleeve 52. The diversion sleeve 52 is connected to the air outlet end. The combustion chamber 3 is located inside the diversion sleeve 52. A diversion plate 6 is provided between the diversion sleeve 52 and the combustion chamber 3. The diversion plate 6 is provided with intersecting combustion-supporting gas nozzles 61 and swirling channels 62. The combustion-supporting gas sleeve 51 is sleeved on the outside of the diversion sleeve 52. A combustion-supporting gas inlet pipe 53 is provided on the bottom side of the combustion-supporting gas sleeve 51 for introducing combustion-supporting gas.

[0030] A combustion-supporting sleeve 51 has a combustion-supporting nozzle 54 inside, which extends into the distribution sleeve 52 and is located on one side of the combustion-supporting nozzle 61. This nozzle precisely guides the combustion-supporting gas to the nozzle 61, allowing it to be injected into the combustion chamber 3 and mixed with the primary air entering from the swirl channel 62, thus promoting combustion. An annular air chamber 55 is formed between the distribution sleeve 52 and the combustion chamber 3. A vent 56 communicating with the combustion chamber 3 is provided on the inner wall of the annular air chamber 55. Primary air can enter the combustion chamber 3 through the vent 56 at a suitable angle and speed, further optimizing the airflow distribution and mixing effect within the combustion chamber 3. The swirl channel 62 includes a pulverized coal nozzle 621 and swirl blades 622. The swirl blades 622 are obliquely connected to one side of the pulverized coal nozzle 621. When primary air carrying pulverized coal passes through the swirl channel 62, the swirl blades 622 cause the pulverized coal to swirl, increasing the uniformity of mixing between the pulverized coal, combustion-supporting gas, and air, and improving combustion efficiency.

[0031] The flue gas recirculation mechanism 7 includes a flue gas recirculation pipe 71. One end of the flue gas recirculation pipe 71 is connected to the air inlet hood 22 via a flue gas flow regulating valve 72, and the other end of the flue gas pipe is connected to a flue gas pre-processor 73. The flue gas pre-processor 73 is connected to the boiler exhaust port and is used to treat the high-temperature flue gas discharged from the boiler. The flue gas pre-processor 73 includes a treatment chamber 731 and a filter chamber 732. The filter chamber 732 is connected to the treatment chamber 731 via a flue gas inlet pipe 733. The top of the treatment chamber 731 is connected to the flue gas pipe. The treatment chamber 731 contains an alkaline aqueous solution (such as NaOH or Ca(OH)2 solution). The flue gas inlet pipe 733 extends into the treatment chamber 731 and is connected to an aerator 734. The aerator 734 allows the flue gas to come into full contact with the alkaline aqueous solution, which can neutralize some acidic pollutants, including some nitrogen oxides, thus removing some acidic pollutants from the flue gas.

[0032] The filter chamber 732 is connected to the boiler exhaust port. The filter chamber 732 is filled with packing material, including crushed stone layers on both sides and an adsorption layer in the middle. The adsorption layer is made of activated carbon powder, which has a well-developed pore structure and a large specific surface area. It can remove some residual impurities and harmful substances such as nitrogen oxides through physical adsorption, further purifying the flue gas. The purified flue gas passes through the flue gas circulation pipe 71, and after the flow rate is regulated by the flue gas flow regulating valve 72, it enters the air inlet hood 22 to mix with fresh air and pulverized coal.

[0033] Example 2 The present invention also provides a low NO content in a thermal power plant boiler according to Example 1. x The combustion method of a pulverized coal burner includes the following steps: S1. Fuel and air premixing: Start the air supply device 2, and the fan 21 will transport outside air through the air inlet hood 22 to the air supply chamber 11 of the air supply mechanism 1. At the same time, pulverized coal enters the air inlet hood 22 at a set flow rate after passing through the pulverized coal inlet and being filtered for impurities by the filter screen 23. With the help of the pulverized coal flow regulating valve, it will be initially mixed with the air during the air intake process to form a primary airflow carrying pulverized coal. In addition, some of the flue gas discharged from the boiler exhaust port will be treated by the flue gas pre-processor 73 and then pass through the flue gas circulation pipe 71. After the flow rate is regulated by the flue gas flow regulating valve 72, it will be mixed with the air-pulverized coal mixture entering from the air inlet hood 22 to further optimize the composition of the combustion raw materials.

[0034] S2, Combustion supply: Combustion enters the combustion sleeve 51 through the combustion inlet pipe 53. After being guided by the combustion nozzle 54 inside the combustion sleeve 51, it is injected into the combustion chamber 3 from the combustion nozzle 61 to provide additional combustion support for the combustion process. S3. Airflow distribution and mixing: The primary air carrying pulverized coal enters the diversion sleeve 52 from the air outlet of the air supply mechanism 1, and enters the combustion chamber 3 through the staggered swirl channels 62 on the diversion plate 6. The swirl blades 622 in the swirl channels 62 cause the pulverized coal to form a swirl, which increases the degree of mixing between the pulverized coal and the air. At the same time, the primary air also enters the combustion chamber 3 at a suitable angle and speed through the ventilation port 56 on the inner wall of the annular air cavity 55, and mixes fully with the combustion gas entering from the combustion gas nozzle 61, creating good conditions for combustion. S4. Ignition and Combustion: After the primary air and combustion-supporting gas are distributed and positioned within the combustion chamber 3, the ignition gun 4 is activated. The ignition gun 4 passes through the air inlet and outlet of the air supply mechanism 1, effectively igniting the high-concentration coal powder gas flow in the center and initiating the combustion process. In the initial stage of combustion, due to the staged introduction of combustion-supporting gas and primary air, a low-oxygen, fuel-rich atmosphere is formed in the combustion zone, effectively suppressing fuel-type NO. x As combustion progresses, the flow rate and ratio of primary air, combustion gas, and recirculated flue gas are continuously optimized by adjusting the air flow regulating mechanism 13, the valves on the combustion gas intake pipe 53, and the flue gas flow regulating valve 72, thereby ensuring the stability of the combustion process. S5. Late Combustion and Burnout: In the later stages of combustion, as fuel is consumed, the air flow regulating mechanism 13 is further adjusted to increase the amount of air entering the combustion chamber 3. Simultaneously, the replenishment of combustion-supporting fuel is rationally controlled to ensure that unburned pulverized coal is fully burned in a sufficient oxygen environment, reducing the carbon content of fly ash and improving combustion efficiency. Throughout the combustion process, parameters such as temperature and oxygen content within the combustion chamber 3 are continuously monitored. Based on the monitoring data, various regulating mechanisms and valves are adjusted in real time to ensure efficient and stable combustion and achieve low NO₂ levels. x emission.

[0035] Application Example 1 The low-NOx pulverized coal burner of Embodiment 1 of this invention was installed on a boiler in a 300MW thermal power plant. In the burner's air supply mechanism 1, the diameter of air supply chamber one 11 is 800mm, and the diameter of air supply chamber two 12 is 600mm. The V-shaped guide plate 131 of the air flow regulating mechanism 13 has a length of 500mm, and the lengths of the upper tilting plate 132 and the lower tilting plate 133 are both 300mm. The power of the regulating motor 137 is 5kW. The rated air volume of the fan 21 of the air supply device 2 is 100,000 m³ / h. 3 / h, the cross-sectional area of ​​the air inlet shroud 22 is 2m². 2The diameter of the pulverized coal inlet is 200mm, and the adjustment range of the pulverized coal flow regulating valve is 0-50t / h. In the flue gas recirculation mechanism 7, the diameter of the flue gas circulation pipe 71 is 400mm, and the adjustment accuracy of the flue gas flow regulating valve 72 is ±5%. In the combustion-supporting gas conveying mechanism 5, the diameter of the combustion-supporting sleeve 51 is 800mm, the diameter of the diversion sleeve 52 is 1000mm, the diameter of the combustion-supporting gas nozzle 54 is 50mm, the diameter of the combustion-supporting gas nozzle 61 is 30mm, the diameter of the pulverized coal nozzle 621 of the swirl channel 62 is 80mm, and the inclination angle of the swirl blade 622 is 45°.

[0036] During combustion, the primary air velocity is controlled at 25 m / s, and the pulverized coal concentration is 0.6 kg / m³. 3 The auxiliary combustion gas is natural gas, and its flow rate is adjusted according to the combustion conditions via the auxiliary combustion gas inlet pipe valve 53 to maintain a suitable ratio with the primary air. The flue gas recirculation volume accounts for 15% of the total air volume and is precisely controlled by the flue gas flow regulating valve 72. The air flow regulating mechanism 13 maintains the opening angle of the upper tilting plate 132 and the lower tilting plate 133 at 30°, ensuring stable primary air flow and velocity entering the combustion chamber 3. After a period of operation and testing, the boiler's NOx... x Emission concentration remained stable at 180 mg / Nm 3 The boiler achieves a thermal efficiency of over 90%, operates stably within a load range of 50%-100%, and exhibits good adaptability to bituminous and lean coal.

[0037] Application Example 2 The technical solution of this invention is applied to the boiler of a 600MW thermal power plant. In the air supply mechanism 1 of the burner, the diameter of the first air supply chamber 11 is 1200mm, and the diameter of the second air supply chamber 12 is 1000mm. The V-shaped guide plate 131 of the air flow regulating mechanism 13 has a length of 800mm, and the lengths of the upper tilting plate 132 and the lower tilting plate 133 are both 500mm. The power of the regulating motor 137 is 10kW. The rated air volume of the fan 21 of the air supply device 2 is 200,000m³. 3 / h, the cross-sectional area of ​​the air inlet shroud 22 is 3m². 2 The diameter of the pulverized coal inlet is 300mm, and the adjustment range of the pulverized coal flow regulating valve is 0-100t / h. In the flue gas recirculation mechanism 7, the diameter of the flue gas circulation pipe 71 is 600mm, and the adjustment accuracy of the flue gas flow regulating valve 72 is ±3%. In the combustion-supporting gas conveying mechanism 5, the diameter of the combustion-supporting sleeve 51 is 1200mm, the diameter of the diversion sleeve 52 is 1500mm, the diameter of the combustion-supporting gas nozzle 54 is 80mm, the diameter of the combustion-supporting gas nozzle 61 is 50mm, the diameter of the pulverized coal nozzle 621 of the swirl channel 62 is 120mm, and the inclination angle of the swirl blade 622 is 30°.

[0038] During operation, the primary air velocity is maintained at 30 m / s, and the pulverized coal concentration is 0.5 kg / m³. 3 The combustion-supporting gas is hydrogen, and its flow rate is regulated by the valve on the combustion-supporting gas inlet pipe 53 to achieve a good mixing ratio with the primary air. The flue gas recirculation volume accounts for 20% of the total air volume and is strictly controlled by the flue gas flow regulating valve 72. The air flow regulating mechanism 13 is adjusted so that the opening angle of the upper tilting plate 132 and the lower tilting plate 133 is 40° to ensure a stable supply of primary air.

[0039] Actual operating results show that the NO of this boiler x Emission concentration can be controlled at 150 mg / Nm³ 3 The boiler's thermal efficiency reaches over 92%, and it operates stably within a load range of 30%-100%, achieving efficient and low-NOx combustion for both anthracite and lignite.

[0040] Table 1 Comparison of running parameters between Application Example 1 and Application Example 2

[0041] The above embodiments are only some implementations of the present invention. In practical applications, the structure and operating parameters of the burner can be further optimized and adjusted according to the boiler parameters and requirements of different thermal power plants to achieve optimal low NO₂ levels. x Combustion effect.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A low-NOx boiler for thermal power plants x A pulverized coal burner includes an air supply mechanism, an air supply device on one side of the air inlet end of the air supply mechanism, a combustion chamber on the air outlet end of the air supply mechanism, and an ignition gun penetrating through the air inlet end and the air outlet end within the air supply mechanism, characterized in that: A combustion chamber and an air outlet are connected by a combustion gas delivery mechanism. The combustion gas delivery mechanism includes a combustion gas sleeve and a diversion sleeve. The diversion sleeve is connected to the air outlet. The combustion chamber is located inside the diversion sleeve. A diversion plate is provided between the diversion sleeve and the combustion chamber. The diversion plate is provided with intersecting combustion gas nozzles and swirling channels. The combustion gas sleeve is fitted on the outside of the diversion sleeve. A combustion gas inlet pipe is provided on the bottom side of the combustion gas sleeve. A combustion gas nozzle is provided on the inside of the combustion gas sleeve. The combustion gas nozzle extends into the diversion sleeve and is located on one side of the combustion gas nozzle.

2. A low-NOx boiler for thermal power plants according to claim 1 x A pulverized coal burner, characterized in that: The air supply device includes a fan and an air inlet hood. The fan and the air inlet hood are symmetrically arranged on both sides of the air supply mechanism. A pulverized coal inlet is provided on the front side of the air inlet hood. A filter screen is provided at the pulverized coal inlet. A pulverized coal flow regulating valve is provided inside the filter screen. The end of the air inlet hood away from the air supply mechanism is connected to the flue gas recirculation mechanism.

3. A low-NOx boiler for thermal power plants according to claim 1 x A pulverized coal burner, characterized in that: The flue gas recirculation mechanism includes a flue gas recirculation duct. One end of the flue gas recirculation duct is connected to the air inlet hood through a flue gas flow regulating valve, and the other end of the flue gas duct is connected to the flue gas pre-processor. The flue gas pre-processor is connected to the boiler exhaust port.

4. A low-NOx boiler for thermal power plants according to claim 3 x A pulverized coal burner, characterized in that: The flue gas pre-processor includes a treatment chamber and a filter chamber. The filter chamber is connected to the treatment chamber through a flue gas inlet pipe. The top of the treatment chamber is connected to a flue gas duct. The treatment chamber is filled with an alkaline aqueous solution. The flue gas inlet pipe extends into the treatment chamber and is connected to an aerator. The filter chamber is connected to the boiler exhaust port. The filter chamber is filled with packing material, which includes crushed stone layers on both sides and an adsorption layer in the middle. The adsorption layer is made of activated carbon powder.

5. A low-NOx boiler for thermal power plants according to claim 1 x A pulverized coal burner, characterized in that: An annular air cavity is formed between the flow divider sleeve and the combustion chamber, and a ventilation port communicating with the combustion chamber is provided on the inner wall of the annular air cavity.

6. A low-NOx boiler for thermal power plants according to claim 1 x A pulverized coal burner, characterized in that: The swirl channel includes a pulverized coal nozzle and swirl blades, with the swirl blades obliquely connected to one side of the pulverized coal nozzle.

7. A low-NOx boiler for thermal power plants according to claim 1 x A pulverized coal burner, characterized in that: The air supply mechanism includes two interconnected air supply chambers, Air Supply Chamber 1 and Air Supply Chamber 2. An air flow regulating mechanism is provided between Air Supply Chamber 1 and Air Supply Chamber 2. Air Supply Chamber 1 is connected to the air supply device, and Air Supply Chamber 2 is connected to the combustion-supporting gas delivery mechanism.

8. A low-NOx boiler for thermal power plants according to claim 7 x A pulverized coal burner, characterized in that: The airflow regulating mechanism includes a V-shaped guide plate, an upper flip plate, and a lower flip plate. The V-shaped guide plate is located in the middle, and the upper and lower flip plates are symmetrically arranged on the upper and lower sides of the V-shaped guide plate. The middle part of the upper flip plate is connected to flip rod one, and the middle part of the lower flip plate is connected to flip rod two. One end of flip rod one is connected to flip rod two through a connecting rod assembly, and the other end of flip rod one is connected to the regulating motor.

9. A low-NOx boiler for thermal power plants as described in any one of claims 1-8 x The combustion method of a pulverized coal burner is characterized by: Includes the following steps, S1. Start the air supply device, which will initially mix the coal powder with the air during the air intake process to form a primary airflow carrying the coal powder; S2. The combustion gas enters the combustion gas sleeve through the combustion gas inlet pipe, and is then injected into the combustion chamber after being guided by the combustion gas nozzle inside the combustion gas sleeve. S3. The primary air carrying pulverized coal enters the diversion sleeve from the air outlet of the air supply mechanism, and enters the combustion chamber through the staggered swirl channels on the diversion plate, where it is fully mixed with the combustion-supporting gas. S4. Start the ignition gun to ignite the pulverized coal and begin the combustion process.

Images