Tangent circle combustion boiler system
By using coal powder air mixing components and flue gas recirculation technology in the cut-circular combustion boiler, a high-temperature and high-pressure air-oxygen-flue gas mixture is formed, and the burner layout is optimized, and the boiler thermal deviation and combustion stability are solved in the deep peak condition. The problem of this problem improves operational safety and economy and reduces NOx emissions.
Patent Information
- Application Number
- CN202421165501.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-27
- Publication Date
- 2025-01-07
- Estimated Expiration
- 2034-05-27
AI Technical Summary
In the deep peak condition, the cut-circular combustion boiler faces the problems of large thermal deviation and poor combustion stability, which leads to an increase in the amount of NOx generated by the pipe wall of the heated surface, which seriously affects the safety, economy and flexibility of the unit.
A combined system using a coal powder air mixing component, a medium pressure air generation component, a medium pressure oxygen generation component, a burner, a furnace and a flue gas recirculation fan is used to form high-temperature and high-pressure air-oxygen-smoke by pressurizing and heating the air and oxygen. Gas mixture, uniformly input to the burner and furnace, optimize burner arrangement and flue gas recirculation to ensure more full and even combustion.
Solve the problems of large thermal deviation and poor combustion stability of boilers under deep peak condition, improve the safety, economy and flexibility of boiler operation, reduce NOx emissions, prevent the heated surface from over-temperature bursting, and improve the coal powder ignition. Combustion stability.
Smart Images
Figure CN222316962U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of coal-fired power generation, and in particular to a tangentially fired boiler system. Background Art
[0002] As the proportion of renewable energy power generation continues to increase, the deep peak-shaving capability of coal-fired power generation is becoming increasingly important. The deep peak-shaving operation of coal-fired power generation is a technical support for participating in auxiliary services in the power market, and it is also an important basis for ensuring the safe and stable operation of the power grid. The boiler is one of the key equipment in a coal-fired power generation unit, and the deep peak-shaving capability of the boiler basically determines the deep peak-shaving capability of the unit. Under the deep peak-shaving condition of the unit, the boiler generally faces the problem of large thermal deviation, and the problem of overheating of the heating surface tube wall or even tube burst is prominent, which seriously threatens the safe and stable operation of the unit.
[0003] Tangentially fired boilers are a commonly used form of pulverized coal combustion and are widely used in large-capacity coal-fired units. Under deep peak load regulation, tangentially fired boilers face problems such as uneven combustion in the furnace, insufficient water power, and poor combustion stability. The temperature distribution of the heating surface tube wall is uneven and easily overheated. The main / reheat steam temperature deviates far from the design. The NOx generation in the furnace increases significantly, and the pulverized coal combustion stability ability decreases significantly, which seriously affects the safety, economy and flexibility of the unit. The above problems need to be solved. Utility Model Content
[0004] In order to solve the problems of large thermal deviation and poor combustion stability of boilers under deep peak load regulation and improve the safety, economy and flexibility of boiler operation, the present application provides a tangentially fired boiler system, which adopts the following technical solutions:
[0005] The present application provides a tangential combustion boiler system, comprising a pulverized coal-air mixing component, a medium-pressure air generating component, a medium-pressure oxygen generating component, a burner, a furnace, a gas mixer and a flue gas recirculation fan, wherein the gas outlet end of the pulverized coal-air mixing component is connected to the burner, and the burner is installed in the furnace, the medium-pressure air generating component and the medium-pressure oxygen generating component are both connected to the gas inlet end of the gas mixer, the gas outlet end of the gas mixer is connected to the burner, one side of the gas outlet end of the furnace is connected to the gas inlet end of the flue gas recirculation fan, and the gas outlet end of the flue gas recirculation fan is connected to the gas inlet end of the gas mixer, wherein the burner comprises a first burner and a second burner, the first burner is installed at the four diagonals of the furnace, and the second burner is installed on the wall of the furnace.
[0006] Preferably, the pulverized coal-air mixing assembly includes a first fan, an air heater and a coal mill, the air outlet end of the first fan is connected to the air inlet end of the air heater, the air outlet end of the air heater is connected to the air inlet end of the coal mill, and the air outlet end of the coal mill is connected to a burner.
[0007] Preferably, the medium-pressure air generating component comprises a second fan and an air preheater, the air outlet end of the second fan is connected to the air inlet end of the air preheater, and the air outlet end of the air preheater is connected to the air inlet end of the gas mixer.
[0008] Preferably, the medium-pressure oxygen generation component comprises an air separator and an oxygen heater, the air outlet end of the air separator is connected to the air inlet end of the oxygen heater, and the air outlet end of the oxygen heater is connected to the air inlet end of the gas mixer.
[0009] Preferably, the first burner includes a plurality of pulverized coal burners and a plurality of first smoke and air burners, the pulverized coal burners and the first smoke and air burners are arranged at intervals along the height direction of the furnace, the air inlet end of the pulverized coal burner is connected to the air outlet end of the coal mill, and the air inlet end of the first smoke and air burner is connected to one of the air outlet ends of the gas mixer.
[0010] Preferably, the second burner includes a plurality of second smoke and air burners, and the plurality of second smoke and air burners are arranged at intervals along the height direction of the furnace, and the air inlet end of the second smoke and air burner is connected to the other air outlet end of the gas mixer.
[0011] Preferably, each of the first burner and the second burner is respectively provided with at least three layers.
[0012] Preferably, each corresponding layer between the first burner and the second burner is arranged in parallel with equal height.
[0013] Preferably, the flow velocity at the outlet end of the second smoke and air burner is greater than or equal to 20 m / s.
[0014] In summary, compared with the prior art, the technical solution provided by this application has at least the following beneficial effects:
[0015] The present application pressurizes and heats the input air through a pulverized coal-air mixing component, processes the obtained high-temperature and high-pressure air and mixes it with raw coal, and obtains a pulverized coal-air mixture that is input into the burner and furnace for combustion; the air is pressurized and heated by a medium-pressure air generating component to generate high-temperature medium-pressure air that is input into a gas mixer; the oxygen in the air is then separated by a medium-pressure oxygen generating component and heated; the obtained high-temperature medium-pressure oxygen is input into the gas mixer and mixed with the high-temperature medium-pressure air, and then input into the burner and furnace to support the combustion of pulverized coal; the burner evenly inputs the gas into the furnace for combustion; the high-temperature flue gas obtained by the combustion is circulated to the gas mixer through a flue gas recirculation fan for mixing; the obtained high-temperature medium-pressure air-oxygen-flue gas mixture is then input into the burner and furnace to support the combustion of pulverized coal, thereby making the combustion more complete and uniform, solving the problems of large thermal deviation and poor combustion stability of the boiler under deep peak-shaving conditions, and improving the safety, economy and flexibility of boiler operation. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a structural schematic diagram of a tangentially fired boiler system described in an embodiment of the present application.
[0017] Figure 2 It is a schematic structural diagram of the horizontal arrangement of the circular burner described in the embodiment of the present application.
[0018] Figure 3 It is a schematic structural diagram of the vertical arrangement of the circular burner described in the embodiment of the present application.
[0019] Description of reference numerals:
[0020] 1. First fan; 2. Air heater; 3. Coal mill; 4. Burner; 41. First burner; 411. Pulverized coal burner; 412. First smoke and air burner; 42. Second burner; 421. Second smoke and air burner; 5. Furnace; 6. Second fan; 7. Air preheater; 8. Gas mixer; 9. Air separation unit; 10. Oxygen heater; 11. Flue gas recirculation fan. DETAILED DESCRIPTION
[0021] The following combination Figure 1-Figure 3 The present application is described in further detail. The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to be limiting.
[0022] Reference Figure 1 The present application involves a tangential combustion boiler system, which specifically includes a pulverized coal-air mixing component, a medium-pressure air generating component, a medium-pressure oxygen generating component, a burner 4, a furnace 5, a gas mixer 8 and a flue gas recirculation fan 11, the gas outlet end of the pulverized coal-air mixing component is connected to the burner 4, the burner 4 is installed in the furnace 5, the medium-pressure air generating component and the medium-pressure oxygen generating component are both connected to the air inlet end of the gas mixer 8, the gas outlet end of the gas mixer 8 is connected to the burner 4, one side of the gas outlet end of the furnace 5 is connected to the air inlet end of the flue gas recirculation fan 11, and the gas outlet end of the flue gas recirculation fan 11 is connected to the air inlet end of the gas mixer 8, wherein the burner 4 includes a first burner 41 and a second burner 42, the first burner 41 is installed at the four diagonals of the furnace 5, and the second burner 42 is installed on the wall of the furnace 5.
[0023] Specifically, the present application obtains air and raw coal through a pulverized coal-air mixing assembly, pressurizes and heats the input air, processes the air to obtain high-temperature and high-pressure air and mixes it with the raw coal, and obtains a pulverized coal-air mixture that is input into the burner 4 and the furnace 5 for combustion. Air is obtained through a medium-pressure air generation assembly, pressurized and heated, and high-temperature medium-pressure air is generated and input into one of the input ports of the gas mixer 8. Air is then obtained through the medium-pressure oxygen generating component, the oxygen in the air is separated and then heated, and the obtained high-temperature medium-pressure oxygen is input to another input port of the gas mixer 8, and the high-temperature medium-pressure oxygen is mixed with the high-temperature medium-pressure air through the gas mixer 8 and then input to the burner 4, and the burner 4 evenly inputs the gas into the furnace 5 to support the combustion of coal powder. The high-temperature flue gas obtained by the combustion is circulated to the third input port of the gas mixer 8 through the flue gas recirculation fan 11, and then mixed again through the gas mixer 8 to obtain a high-temperature medium-pressure air-oxygen-flue gas mixture, which is then input to the burner 4 and the furnace 5 to support the combustion of coal powder, so that the combustion is more complete and uniform, thereby solving the problems of large thermal deviation and poor combustion stability of the boiler under deep peak-shaving conditions, and improving the safety, economy and flexibility of boiler operation.
[0024] As one of the embodiments, the pulverized coal-air mixing assembly includes a first fan 1, an air heater 2 and a coal mill 3, the air outlet end of the first fan 1 is connected to the air inlet end of the air heater 2, the air outlet end of the air heater 2 is connected to the air inlet end of the coal mill 3, and the air outlet end of the coal mill 3 is connected to the burner 4.
[0025] Specifically, the first fan 1 draws air from the atmosphere, the air is pressurized into high-pressure air, and the high-pressure air is input into the air heater 2; the air heater 2 receives the high-pressure air output by the first fan 1, the high-pressure air is heated into high-temperature and high-pressure air, and the high-temperature and high-pressure air is input into the coal mill 3; the coal mill 3 simultaneously receives the raw coal and the high-temperature and high-pressure air output by the air preheater 7, the high-temperature and high-pressure air dries the raw coal and prepares it into a coal powder-air mixture, and the coal powder-air mixture is input into the burner 4; the burner 4 receives the coal powder-air mixture output by the coal mill 3, and the coal powder-air mixture is input into the furnace 5 for combustion after mixing and distribution.
[0026] As one embodiment, the medium-pressure air generating component includes a second fan 6 and an air preheater 7, the air outlet end of the second fan 6 is connected to the air inlet end of the air preheater 7, and the air outlet end of the air preheater 7 is connected to the air inlet end of the gas mixer 8.
[0027] Specifically, the second fan 6 draws air from the atmosphere, the air is pressurized into medium-pressure air, and the medium-pressure air is input into the air preheater 7; the air preheater 7 receives the medium-pressure air output by the second fan 6, the medium-pressure air is heated into high-temperature medium-pressure air, and the high-temperature medium-pressure air is input into the gas mixer 8, and the high-temperature medium-pressure air is used as one of the gases mixed by the gas mixer 8.
[0028] As one embodiment, the medium-pressure oxygen generation component includes an air separator 9 and an oxygen heater 10, wherein the air outlet of the air separator 9 is connected to the air inlet of the oxygen heater 10, and the air outlet of the oxygen heater 10 is connected to the air inlet of the gas mixer 8.
[0029] Specifically, the air separator 9 draws air from the atmosphere, separates the medium-pressure oxygen from the air, and the medium-pressure oxygen is input into the oxygen heater 10; the oxygen heater 10 receives the medium-pressure oxygen output by the air separator 9, and the medium-pressure oxygen is heated into high-temperature medium-pressure oxygen, and the high-temperature medium-pressure oxygen is input into the gas mixer 8.
[0030] The flue gas recirculation fan 11 extracts part of the high-temperature flue gas from the rear end of the furnace 5, and the high-temperature flue gas is pressurized into high-temperature medium-pressure flue gas, which is input into the gas mixer 8; the gas mixer 8 simultaneously receives the high-temperature medium-pressure air output by the air preheater 7, the high-temperature medium-pressure oxygen output by the oxygen heater 10, and the high-temperature medium-pressure flue gas output by the flue gas recirculation fan 11, and the high-temperature medium-pressure air, high-temperature medium-pressure oxygen, and high-temperature medium-pressure flue gas are mixed into a high-temperature air-oxygen-flue gas mixture, which is input into the burner 4; the burner 4 receives the high-temperature air-oxygen-flue gas mixture output by the gas mixer 8, and the high-temperature air-oxygen-flue gas mixture is distributed and rectified before being input into the furnace 5 for combustion; the furnace 5 receives the pulverized coal-air mixture and the high-temperature air-oxygen-flue gas mixture output by the burner 4, and the pulverized coal reacts with the air, oxygen, and flue gas.
[0031] As one embodiment, the burner 4 includes a first burner 41 and a second burner 42 . The first burner 41 is installed at four diagonal corners of the furnace 5 , and the second burner 42 is installed on the wall of the furnace 5 .
[0032] Specifically, refer to Figure 2 The burner 4 is installed on the furnace 5, including a first burner 41 and a second burner 42. The first burner 41 is installed on the four diagonals of the furnace 5, and the second burner 42 is installed on the wall of the furnace 5, and the second burner 42 is installed on the fire side of the wall of the furnace 5. Specifically, the number of second burners 42 is usually the same as the first burner 41. For example, the shape of the furnace 5 when viewed from above is a quadrilateral, each first burner 41 is installed on the diagonal of the furnace 5, and the second burner 42 is installed on the wall close to one of the first burners 41, so that the flue gas in the furnace 5 can circulate and burn, thereby achieving the effect of uniform combustion and sufficient combustion.
[0033] As one embodiment, the first burner 41 includes a plurality of pulverized coal burners 411 and a plurality of first smoke and air burners 412, and the pulverized coal burners 411 and the first smoke and air burners 412 are arranged at intervals along the height direction of the furnace 5, and the air inlet end of the pulverized coal burner 411 is connected to the air outlet end of the coal mill 3, and the air inlet end of the first smoke and air burner 412 is connected to one of the air outlet ends of the gas mixer 8.
[0034] Specifically, the pulverized coal burner 411 receives the pulverized coal-air mixture output by the coal mill 3, and the pulverized coal-air mixture enters the furnace 5 for combustion after being mixed, distributed, and ignited. The first smoke-air burner 412 receives a portion of the high-temperature air-oxygen-smoke mixture output by the gas mixer 8, and the high-temperature air-oxygen-smoke mixture enters the furnace 5 to support the stable ignition and rapid combustion of the pulverized coal.
[0035] As one embodiment, the second burner 42 includes a plurality of second smoke and air burners 421 , which are arranged at intervals along the height direction of the furnace 5 , and the air inlet end of the second smoke and air burner 421 is connected to the other air outlet end of the gas mixer 8 .
[0036] Specifically, the second burner 42 is a second smoke and air burner 421, which receives another high-temperature air-oxygen-smoke mixture output by the gas mixer 8. The high-temperature air-oxygen-smoke mixture enters the furnace 5 to assist the coal powder to burn fully and correct the combustion dynamic field of the inscribed circle in the furnace. The outlet flow rate of the second smoke and air burner 421 is not less than 20m / s, so that the combustion smoke in the furnace 5 can be burned according to the Figure 2 The combustion is carried out in a cyclic manner.
[0037] As one embodiment, each of the first burner 41 and the second burner 42 is respectively provided with at least three layers. Each corresponding layer between the first burner 41 and the second burner 42 is arranged in parallel at the same height. The first burner 41 and the second burner 42 are arranged in at least three layers and are arranged in parallel at the same height.
[0038] Specifically, refer to Figure 3 The pulverized coal burner 411, the first smoke and air burner 412 or the second smoke and air burner 421 of each layer are kept at the same height, so that each layer has Figure 2Circulation combustion, so that the pulverized coal in the furnace 5 is fully and evenly burned. The gas mixer 8 adopts a Venturi structure. The design pressure head of the first fan 1 is 10-15kPa, the design pressure head of the second fan 6 is 3-5kPa, and the design pressure head of the flue gas recirculation fan 11 is 3-5kPa. The design pressure head of the oxygen output by the air separator 9 is 3-5kPa. The high-temperature flue gas flow rate extracted by the flue gas recirculation fan 11 is 0.5-1.5 times the air flow rate of the first fan 1, and the temperature range of the extracted high-temperature flue gas is 400℃-800℃; the air heater 2 and the oxygen heater 10 use tubular heat exchangers, and the heat source is high-temperature flue gas. The air preheater 7 uses a rotary heat exchanger, and the heat source is high-temperature flue gas. The oxygen concentration of the high-temperature air-oxygen-flue gas mixture output by the gas mixer 8 is not less than 21%, and the temperature is not less than 350℃.
[0039] The present application provides a tangential combustion boiler system, which optimizes the arrangement of the burner 4 and the flue gas recirculation, improves the tangential combustion dynamic characteristics in the furnace under low load conditions and the radiation-convection heat absorption characteristics of the working medium, reduces the thermal deviation of the boiler, increases the main / reheat steam temperature, reduces NOx emissions during the combustion process, prevents overheating of the boiler heating surface and tube burst, and increases the oxygen concentration of the recirculated flue gas by supplementing oxygen, optimizes the boiler oxygen distribution pattern, improves the ignition and combustion stability of coal powder, and improves the safety, economy and flexibility of boiler operation under deep peak regulation conditions. The boiler system has the advantages of simple structure, flexible adjustment and reliable operation.
[0040] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described device and product can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.
[0041] In several embodiments provided in this application, it should be understood that the disclosed system can be implemented in other ways.
[0042] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A tangentially fired boiler system, characterized in that: It includes a pulverized coal-air mixing component, a medium-pressure air generating component, a medium-pressure oxygen generating component, a burner, a furnace, a gas mixer and a flue gas recirculation fan, the gas outlet end of the pulverized coal-air mixing component is connected to the burner, the burner is installed in the furnace, the medium-pressure air generating component and the medium-pressure oxygen generating component are both connected to the air inlet end of the gas mixer, the gas outlet end of the gas mixer is connected to the burner, one side of the gas outlet end of the furnace is connected to the air inlet end of the flue gas recirculation fan, the gas outlet end of the flue gas recirculation fan is connected to the air inlet end of the gas mixer, wherein the burner includes a first burner and a second burner, the first burner is installed at the four diagonals of the furnace, and the second burner is installed on the wall of the furnace.
2. The tangentially fired boiler system according to claim 1, characterized in that: The pulverized coal-air mixing assembly includes a first fan, an air heater and a coal mill, wherein the air outlet of the first fan is connected to the air inlet of the air heater, the air outlet of the air heater is connected to the air inlet of the coal mill, and the air outlet of the coal mill is connected to a burner.
3. The tangentially fired boiler system according to claim 1, characterized in that: The medium-pressure air generating assembly comprises a second fan and an air preheater, wherein an air outlet of the second fan is connected to an air inlet of the air preheater, and an air outlet of the air preheater is connected to an air inlet of the gas mixer.
4. The tangentially fired boiler system according to claim 3, characterized in that: The medium-pressure oxygen generation component comprises an air separator and an oxygen heater, wherein the gas outlet of the air separator is connected to the gas inlet of the oxygen heater, and the gas outlet of the oxygen heater is connected to the gas inlet of the gas mixer.
5. The tangentially fired boiler system according to claim 1, characterized in that: The first burner includes a plurality of pulverized coal burners and a plurality of first smoke and air burners, and the pulverized coal burners and the first smoke and air burners are arranged at intervals along the height direction of the furnace, the air inlet end of the pulverized coal burner is connected to the air outlet end of the coal mill, and the air inlet end of the first smoke and air burner is connected to one of the air outlet ends of the gas mixer.
6. The tangentially fired boiler system according to claim 1, characterized in that: The second burner comprises a plurality of second smoke and air burners, which are arranged at intervals along the height direction of the furnace, and the air inlet end of the second smoke and air burner is connected to the other air outlet end of the gas mixer.
7. The tangentially fired boiler system according to claim 1, characterized in that: Each of the first burner and the second burner is respectively provided with at least three layers.
8. The tangentially fired boiler system according to claim 1, characterized in that: Each corresponding layer between the first burner and the second burner is arranged in parallel with the same height.
9. The tangentially fired boiler system according to claim 6, characterized in that: The flow velocity at the outlet end of the second smoke and air burner is greater than or equal to 20m / s.