Boiler system and boiler combustion control method

Abstract

The invention provides a boiler system and a boiler combustion control method, and the boiler system comprises a coal grinding mechanism; the boiler is communicated with the coal grinding mechanism through a first pipeline; the particle size sorting device is communicated with the coal grinding mechanism through a second pipeline, and the particle size sorting device is used for sorting coal with a preset particle size; and the first coal bunker communicates with the particle size sorting device through a third pipeline so that the coal with the preset particle size can enter the first coal bunker, and the first coal bunker communicates with the boiler through a fourth pipeline. According to the technical scheme, the problem that the deep peak regulation capacity of the coal-fired unit is insufficient in the related technology is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of boiler combustion technology, and more specifically, to a boiler system and a boiler combustion control method. Background Technology

[0002] Currently, renewable energy generation such as wind and solar power exhibits significant intermittency and volatility, making it difficult to achieve continuous and stable output. Therefore, in order to maintain the real-time power balance and operational stability of the power system, traditional coal-fired power plants need to improve their flexibility and frequently participate in deep peak shaving, that is, operate flexibly under a wide load range.

[0003] In related technologies, the combustion systems of coal-fired power units are mostly designed around high-load conditions. Their structural parameters and operating strategies aim to achieve uniform distribution of heat load and efficient combustion within the furnace under high loads. However, under low-load conditions, they often face insufficient stable combustion capacity, which severely restricts the boiler's ability to participate in deep peak shaving. Furthermore, during rapid load changes in coal-fired power units, the coal mill, limited by its dynamic response characteristics and pulverizing rate, struggles to meet rapidly changing pulverized coal feeding demands in a timely manner, forming a bottleneck that restricts the flexible operation of the boiler. Summary of the Invention

[0004] The main objective of this invention is to provide a boiler system and a boiler combustion control method to solve the problem of insufficient deep peak-shaving capacity of coal-fired power units in related technologies.

[0005] To achieve the above objectives, according to one aspect of the present invention, a boiler system is provided, comprising: a coal pulverizing mechanism; a boiler connected to the coal pulverizing mechanism via a first pipeline; a particle size separation device connected to the coal pulverizing mechanism via a second pipeline, the particle size separation device being used to separate coal of a preset particle size; a first coal bunker connected to the particle size separation device via a third pipeline, so that coal of the preset particle size enters the first coal bunker, the first coal bunker being connected to the boiler via a fourth pipeline.

[0006] Furthermore, the boiler system also includes a second coal bunker, which is connected to a particle size separation device via a fifth pipeline. The particle size of the coal in the second coal bunker is larger than that of the coal in the first coal bunker. The second coal bunker is connected to the boiler via a sixth pipeline.

[0007] Furthermore, the sixth conduit is connected to the first conduit.

[0008] Furthermore, the boiler system also includes a pulverized coal mixing device, which is located at the connection between the sixth pipeline and the first pipeline.

[0009] Furthermore, the boiler system also includes a pulverized coal distribution device, which is connected to the boiler. The first pipeline and the fourth pipeline are both connected to the pulverized coal distribution device.

[0010] Furthermore, there are multiple first, fourth, and sixth pipelines, with multiple first and sixth pipelines arranged in a one-to-one correspondence. The boiler is equipped with multiple feed inlets, and the multiple first, fourth, and feed inlets are connected in a one-to-one correspondence.

[0011] Furthermore, multiple feed inlets are spaced apart along the circumference of the boiler.

[0012] Furthermore, the boiler system also includes multiple burners, each corresponding to a different feed inlet, and the burners are connected to the first pipeline.

[0013] Furthermore, the burner includes a first pulverized coal burner and a second pulverized coal burner. The first pulverized coal burner has a first coal inlet, and the second pulverized coal burner has a second coal inlet. The first pulverized coal burner is connected to a first pipeline, and the second pulverized coal burner is connected to a fourth pipeline.

[0014] Furthermore, the first pulverized coal burner includes a first pulverized coal nozzle, and a first blunt body is disposed inside the first pulverized coal nozzle, with both ends of the first blunt body connected to the first pulverized coal nozzle.

[0015] Furthermore, the second pulverized coal burner includes a second pulverized coal nozzle, and a second blunt body is provided inside the second pulverized coal nozzle, with both ends of the second blunt body connected to the second pulverized coal nozzle.

[0016] Furthermore, the burner also includes a primary and secondary air structure, which is located between the primary pulverized coal burner and the secondary pulverized coal burner.

[0017] Furthermore, the burner also includes a second secondary air structure and a third secondary air structure. The second secondary air structure is located on the side of the first pulverized coal burner away from the second pulverized coal burner, and the third secondary air structure is located on the side of the second pulverized coal burner away from the first pulverized coal burner.

[0018] Furthermore, the first and second secondary air structures have first and second secondary air nozzles, the second and third secondary air structures have second and third secondary air nozzles, and the flow area of ​​the first and second secondary air nozzles is greater than that of the second and third secondary air nozzles.

[0019] Furthermore, the particle size separation device adopts a vibration separation structure, a gravity settling separation structure, or a flow separation structure; and / or, the boiler system also includes a first feeder and a second feeder, with the first feeder installed on a third pipeline and the second feeder installed on a fifth pipeline.

[0020] According to a second aspect of the present invention, a boiler combustion control method is provided to control the above-mentioned boiler system. The boiler combustion control method includes: controlling the boiler system to be in a first operating mode.

[0021] When the boiler system is in the first working mode, the first coal powder generated by the coal grinding mechanism enters the particle size separation device, and the separated first coal powder is transported to the first coal bunker. The first coal powder in the first coal bunker and the second coal powder generated by the coal grinding mechanism are then transported to the boiler.

[0022] According to a third aspect of the present invention, a boiler combustion control method is provided to control the above-mentioned boiler system. The boiler combustion control method includes: controlling the boiler system to be in a second operating mode.

[0023] When the boiler system is in the second working mode, the third coal powder generated by the coal grinding mechanism enters the particle size separation device. The separated third coal powder is then transported to the second coal bunker. The third coal powder in the second coal bunker is mixed with the fourth coal powder generated by the coal grinding mechanism. The mixed third and fourth coal powders are then transported to the boiler.

[0024] According to a fourth aspect of the present invention, a boiler combustion control method is provided to control the above-mentioned boiler system. The boiler combustion control method includes: controlling the boiler system to be in a third operating mode.

[0025] When the boiler system is in the third working mode, the fifth coal powder generated by the coal mill enters the particle size separation device. The particle size separation device separates the fifth coal powder into the sixth coal powder and the seventh coal powder. The sixth coal powder is transported to the first coal bunker, and the seventh coal powder is transported to the second coal bunker. The seventh coal powder in the second coal bunker is mixed with the eighth coal powder generated by the coal mill. The mixed seventh coal powder and the eighth coal powder are then transported to the boiler along with the sixth coal powder.

[0026] Applying the technical solution of this invention, the coal pulverizing mechanism is connected to the boiler via a first pipeline, and the particle size separation device is connected to the coal pulverizing mechanism via a second pipeline, enabling the separation of the pulverized coal produced by the pulverizing mechanism. The first coal bunker is connected to the particle size separation device via a third pipeline, and the first coal bunker is connected to the boiler via a fourth pipeline. Through this arrangement, a portion of the coal pulverized by the coal pulverizing mechanism can be directly transferred to the boiler, while another portion can be transferred to the particle size separation device for separation. The separated coal is then transported to the first coal bunker for storage. When the boiler requires low-load combustion, the coal produced by the coal pulverizing mechanism and the coal in the first coal bunker can be simultaneously transferred to the boiler. This ensures the amount of small-sized pulverized coal particles entering the boiler, thereby guaranteeing stable combustion under low-load conditions. This also enables the boiler to meet the requirements for deep peak shaving. Therefore, the technical solution of this application effectively solves the problem of insufficient deep peak shaving capacity in related technologies for coal-fired power units. Attached Figure Description

[0027] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 A schematic diagram of the boiler system according to the present invention is shown;

[0029] Figure 2 It shows Figure 1 A schematic diagram of the boiler system under wide-load stable combustion conditions;

[0030] Figure 3 It shows Figure 1 A schematic diagram of the boiler system under variable load conditions;

[0031] Figure 4 It shows Figure 1 A partial structural diagram of the boiler system;

[0032] Figure 5 It shows Figure 1 A three-dimensional structural diagram of a portion of the burner in a boiler system;

[0033] Figure 6 It shows Figure 5 A front view schematic diagram of the burner;

[0034] Figure 7 It shows Figure 1 A schematic diagram of a particle size separation device for a boiler system;

[0035] Figure 8 It shows Figure 1 A schematic diagram of another sorting process in the particle size separation device of the boiler system;

[0036] Figure 9 A schematic flowchart of an embodiment of the first boiler combustion control method according to the present invention is shown;

[0037] Figure 10 A schematic flowchart of an embodiment of the second boiler combustion control method according to the present invention is shown;

[0038] Figure 11 A schematic flowchart of an embodiment of the third boiler combustion control method according to the present invention is shown.

[0039] The above figures include the following reference numerals:

[0040] 10. Coal grinding mechanism; 20. Boiler; 30. Particle size sorting device; 40. First coal bunker; 50. Second coal bunker; 60. Pulverized coal distribution device; 70. Burner; 71. First pulverized coal burner; 711. First pulverized coal nozzle; 712. First blunt body; 72. Second pulverized coal burner; 721. Second pulverized coal nozzle; 722. Second blunt body; 73. First and secondary air structure; 731. First and secondary air nozzle; 74. Second and secondary air structure; 741. Second and secondary air nozzle; 75. Third and secondary air structure; 751. Third and secondary air nozzle; 81. First feeder; 82. Second feeder; 83. Pulverized coal mixing device; 101. First pipeline; 102. Second pipeline; 103. Third pipeline; 104. Fourth pipeline; 105. Fifth pipeline; 106. Sixth pipeline. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0043] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0044] The fundamental reason for the difficulty in stable combustion of boilers under low load is that the furnace temperature drops at low loads, resulting in insufficient heat (ignition heat) required for ignition of the pulverized coal gas flow, leading to delayed ignition or even flameout. To solve the above technical problems, such as... Figure 1 , Figure 2 as well as Figure 4 As shown, in some embodiments, the boiler system includes: a coal pulverizing mechanism 10, a boiler 20, a particle size separation device 30, and a first coal bunker 40. The boiler 20 is connected to the coal pulverizing mechanism 10 via a first pipe 101. The particle size separation device 30 is connected to the coal pulverizing mechanism 10 via a second pipe 102, and is used to separate coal of a preset particle size. The first coal bunker 40 is connected to the particle size separation device 30 via a third pipe 103, allowing coal of the preset particle size to enter the first coal bunker 40. The first coal bunker 40 is connected to the boiler 20 via a fourth pipe 104.

[0045] Applying the technical solution of the above embodiments, the coal grinding mechanism 10 is connected to the boiler 20 through the first pipeline 101, and the particle size separation device 30 is connected to the coal grinding mechanism 10 through the second pipeline 102, which can separate the coal powder ground by the coal grinding mechanism 10. The first coal bunker 40 is connected to the particle size separation device 30 through the third pipeline 103, and the first coal bunker 40 is connected to the boiler 20 through the fourth pipeline 104. With the above arrangement, a portion of the coal ground by the coal grinding mechanism 10 can be directly transferred to the boiler 20, and another portion of the coal ground by the coal grinding mechanism 10 can be transferred to the particle size separation device 30 for separation. The separated coal is then transported to the first coal bunker 40 and stored. When the boiler needs to burn at a low load, the coal produced by the coal grinding mechanism 10 and the coal in the first coal bunker 40 can be transferred to the boiler simultaneously. This ensures the amount of small-sized coal powder entering the boiler, thereby ensuring the stable combustion effect of the boiler under low load conditions. This enables the boiler to meet the requirements for deep peak shaving. Therefore, the technical solution of this application effectively solves the problem of insufficient deep peak shaving capacity of coal-fired units in related technologies.

[0046] Specifically, the particle size separation device 30 separates the pulverized coal produced by the coal mill 10 into particles of a preset size, ensuring the stable combustion capability of the coal-fired boiler under wide load operation and enabling rapid load change response. The particle size separation device 30 effectively separates pulverized coal that meets the preset particle size requirements based on the physical differences of coal particles, such as vibration separation structures, gravity settling velocities, or particle size segregation during flow. This pulverized coal is then introduced into the first coal bunker 40 for storage via the third pipeline 103. When the boiler needs to operate under low load conditions, the smaller-sized pulverized coal in the first coal bunker is preferentially introduced into the boiler and fed into the boiler 20 via the fourth pipeline 104. Because the smaller-sized pulverized coal has a larger specific surface area, it can reduce the ignition heat, promote rapid ignition, and ensure stable combustion of the boiler 20 under low load conditions.

[0047] like Figure 1 and Figure 3 As shown, in some embodiments, the boiler system further includes a second coal bunker 50, which is connected to a particle size separation device 30 via a fifth pipe 105. The coal in the second coal bunker 50 has a larger particle size than the coal in the first coal bunker 40. The second coal bunker 50 is connected to the boiler 20 via a sixth pipe 106. The second coal bunker 50, connected to the particle size separation device 30 via the fifth pipe 105, receives and stores large-sized pulverized coal particles separated from the particle size separation device 30. These particles, due to their larger particle size than small pulverized coal particles, have specific combustion characteristics. The second coal bunker 50 is then directly connected to the boiler 20 via the sixth pipe 106, enabling rapid supply of pulverized coal under rapid load changes, compensating for the insufficient pulverizing rate of the coal mill, and achieving immediate response and dynamic balance of the boiler 20.

[0048] The aforementioned setup, by storing large-particle pulverized coal, effectively solves the problem of untimely pulverized coal feeding in traditional systems during load fluctuations, enhancing the flexibility and stability of coal-fired boilers during deep peak shaving. Simultaneously, the particle size separation device 30 ensures effective separation of small and large-particle pulverized coal, allowing small-particle pulverized coal to ignite preferentially under low-load conditions, driving the subsequent combustion of larger-particle pulverized coal, thereby achieving stable combustion.

[0049] like Figure 1 and Figure 3 As shown, in some embodiments, the sixth pipe 106 is connected to the first pipe 101. This arrangement, through the connection between the sixth pipe 106 and the first pipe 101, allows for the addition of pulverized coal from the second coal bunker 50 when needed, mixing it with the pulverized coal directly output from the coal mill 10, and then supplying it to the boiler 20. This ensures that large pulverized coal particles are ignited.

[0050] like Figure 1 and Figure 3 As shown, in some embodiments, the boiler system further includes a pulverized coal mixing device 83, which is located at the connection between the sixth pipeline 106 and the first pipeline 101. The pulverized coal mixing device 83 ensures thorough mixing of pulverized coal from different sources, and under the action of the pulverized coal mixing device 83, the amount of coal supplied to the boiler 20 can be guaranteed, thereby ensuring the combustion effect.

[0051] Specifically, in this embodiment, the pulverized coal mixing device 83 includes a first channel and a second channel. The two ends of the first channel are connected to the first pipeline, the first end of the second channel is connected to the first channel, and the second end of the second channel is connected to the sixth pipeline 106, so that the pulverized coal in the second coal bunker 50 is mixed with the pulverized coal generated by the coal grinding mechanism 10.

[0052] In an embodiment not shown in the figure, in order to ensure the mixing effect, the coal powder mixing device 83 includes a first channel and a second channel. A stirring shaft is provided in the first channel, and the axis of the stirring shaft is perpendicular to the center line of the first channel. The connection between the second channel and the first channel is corresponding to the stirring shaft, that is, the coal powder in the second coal bunker 50 can fall directly onto the stirring shaft. Through the movement of the stirring shaft, the coal powder in the first channel and the coal powder in the second coal bunker 50 are stirred and mixed, thereby making the mixing effect better.

[0053] like Figures 1 to 3As shown, in some embodiments, the boiler system further includes a pulverized coal distribution device 60, which is connected to the boiler 20. Both the first pipeline 101 and the fourth pipeline 104 are connected to the pulverized coal distribution device 60. The pulverized coal distribution device 60 can more precisely control the distribution and combustion process of pulverized coal within the boiler 20. The pulverized coal distribution device 60 improves the flexibility and adaptability of the boiler system and allows for a more uniform distribution of pulverized coal particles within the boiler 20, promoting improved combustion efficiency and balanced furnace heat load, thereby enhancing the dynamic response capability and low-load stable combustion performance of the coal-fired boiler.

[0054] like Figures 1 to 3 As shown, in some embodiments, there are multiple first pipes 101, fourth pipes 104, and sixth pipes 106. Multiple first pipes 101 and multiple sixth pipes 106 are arranged in a one-to-one correspondence. The boiler 20 is provided with multiple feed inlets, and the multiple first pipes 101, multiple fourth pipes 104, and multiple feed inlets are connected in a one-to-one correspondence. Through the above arrangement, the boiler system can more flexibly control the distribution of different pulverized coal flows, ensuring that pulverized coal can be evenly fed into each combustion zone within the boiler 20, thereby optimizing combustion efficiency and reducing problems such as localized overheating or incomplete combustion.

[0055] Under rapid load changes, this multi-pipeline design can quickly respond to pulverized coal feeding demands. By adjusting the flow rate of each pulverized coal stream, it achieves precise control of the boiler's heat load, improving the flexibility and stability of the coal-fired boiler. Furthermore, for wide-load stable combustion conditions, multiple small-sized pulverized coal output streams can more fully utilize the heat within the furnace, promoting ignition and stable combustion of the pulverized coal even at lower loads, further ensuring the stable operation of the coal-fired boiler across a wide load range.

[0056] like Figures 1 to 3 As shown, in some embodiments, multiple feed inlets are spaced apart circumferentially along the boiler 20. This arrangement makes the distribution of pulverized coal more uniform and allows the pulverized coal to cover the internal space of the boiler 20 more evenly, promoting a balanced distribution of the internal thermal field of the boiler 20, thereby improving combustion efficiency and stability.

[0057] Specifically, by using feed inlets spaced out along the circumference, pulverized coal particles can achieve multi-point combustion within the boiler 20, avoiding uneven combustion and excessively high local temperatures caused by a single feed point.

[0058] like Figures 1 to 3As shown, in some embodiments, the boiler system further includes multiple burners 70, each corresponding to a specific feed inlet, and the burners 70 are connected to the first pipeline 101. This arrangement, by matching each burner 70 with a specific feed inlet, enables the regulation of the heat load distribution within the boiler 20, ensuring the uniformity and stability of pulverized coal combustion.

[0059] Under rapid load changes, this layout allows for immediate adjustment of pulverized coal supply. Pre-stored large-particle pulverized coal is quickly replenished, combining with the pulverized coal produced in real-time by the pulverizing unit 10, achieving immediate response in boiler fuel supply and enhancing the dynamic adaptability of the boiler system. Under low-load stable combustion conditions, small-particle pulverized coal is preferentially supplied from the feed inlet of the corresponding burner 70. Its higher specific surface area and lower ignition heat characteristics promote rapid ignition, thereby ensuring the stable operation of the entire combustion process.

[0060] like Figure 5 and Figure 6 As shown, in some embodiments, the burner 70 includes a first pulverized coal burner 71 and a second pulverized coal burner 72. The first pulverized coal burner 71 has a first coal inlet, and the second pulverized coal burner 72 has a second coal inlet. The first pulverized coal burner 71 is connected to a first pipeline 101, and the second pulverized coal burner 72 is connected to a fourth pipeline 104. The first pulverized coal burner 71, connected to the first pipeline 101, is used to transport mixed pulverized coal; the second pulverized coal burner 72, connected to the fourth pipeline 104, is used to transport small-particle pulverized coal. This arrangement allows the burner 70 to simultaneously accept two different particle sizes of pulverized coal, achieving a multi-stage combustion strategy based on particle size distribution through flow allocation. Due to their larger specific surface area, small-particle pulverized coal can ignite rapidly at lower furnace temperatures, thereby igniting larger-particle pulverized coal and effectively improving the combustion stability of coal-fired boilers under low-load conditions. Meanwhile, when the boiler needs to rapidly change loads, the combination of the rapid supply capacity of mixed pulverized coal and the stable combustion advantage of small-particle pulverized coal ensures the continuity and flexibility of the combustion process. This overcomes the limitations of traditional coal-fired boilers in terms of pulverization rate when dealing with rapid load changes, and improves the overall system's response speed and operating efficiency. This combustion scheme based on multi-stage pulverized coal size separation and distribution not only enhances the boiler's stable combustion performance but also significantly improves its ability to participate in deep peak shaving.

[0061] like Figure 5 and Figure 6As shown, in some embodiments, the first pulverized coal burner 71 includes a first pulverized coal nozzle 711, within which a first blunt body 712 is disposed, with both ends of the first blunt body 712 connected to the first pulverized coal nozzle 711. The aforementioned first pulverized coal nozzle 711 effectively allows pulverized coal to pass through, thus enabling it to enter the boiler 20. Simultaneously, the first blunt body 712 enables the separation of concentrated and diluted pulverized coal. Furthermore, because both ends of the first blunt body 712 are connected to the first pulverized coal nozzle 711, the structural strength of the first pulverized coal burner 71 is improved.

[0062] like Figure 5 and Figure 6 As shown, in some embodiments, the first pulverized coal nozzle 711 has a first sidewall, a second sidewall, a third sidewall, and a fourth sidewall arranged sequentially. A first blunt body 712 is connected to both the first and third sidewalls. A first distance exists between the first blunt body 712 and the second sidewall, and a second distance exists between the first blunt body 712 and the fourth sidewall. The first distance is equal to the second distance. This arrangement ensures the symmetry of the first blunt body 712, thereby improving the structural strength of the first pulverized coal nozzle 711 and effectively preventing deformation or failure under large pressure or temperature changes, thus improving the stability and service life of the entire device.

[0063] like Figure 5 and Figure 6 As shown, in some embodiments, the second pulverized coal burner 72 includes a second pulverized coal nozzle 721, within which a second blunt body 722 is disposed, with both ends of the second blunt body 722 connected to the second pulverized coal nozzle 721. This arrangement effectively enhances the structural strength of the second pulverized coal burner 72 and achieves uniform separation and guidance of pulverized coal. Specifically, the connection between the second blunt body 722 and both ends of the second pulverized coal nozzle 721 forms a stable support frame, improving the dimensional stability and structural strength of the second pulverized coal burner 72 under high temperature and high pressure conditions, thereby ensuring the operational reliability of the boiler system.

[0064] It should be noted that the first blunt body 712 and the second blunt body 722 mentioned above serve to separate the parts.

[0065] Specifically, in this embodiment, a plurality of first protrusions are provided on the sidewall of the first blunt body 712, and the first protrusions located on both sides of the first blunt body 712 are spaced apart in the height direction of the first blunt body 712.

[0066] Similarly, a plurality of second protrusions are provided on the side wall of the second blunt body 722, and the second protrusions located on both sides of the second blunt body 722 are spaced apart in the height direction of the second blunt body 722.

[0067] like Figure 5 and Figure 6As shown, in some embodiments, the burner 70 further includes a first and second air structure 73, which is disposed between the first pulverized coal burner 71 and the second pulverized coal burner 72. This arrangement can regulate the air-powder mixing state. Specifically, by configuring the first and second air structure 73, additional airflow can be provided at different locations where pulverized coal enters the burner 70, thereby enhancing the contact and mixing of pulverized coal and air, and promoting complete combustion of the pulverized coal. Under low-load conditions, small pulverized coal particles preferentially enter the boiler 20 through specific pulverized coal inlets of the burner 70. Due to their lower ignition heat requirement, they can ignite quickly and form a stable flame center. Large pulverized coal particles, on the other hand, enter the furnace through other pulverized coal inlets of the burner 70 under high-load or rapidly changing load conditions. The air required for their combustion is supplemented by the first and second air structure 73, ensuring complete combustion of large pulverized coal particles under high load and providing the required heat output during rapid load changes.

[0068] It should be noted that the aforementioned secondary air refers to the second type of air blown into the boiler.

[0069] like Figure 5 and Figure 6 As shown, in some embodiments, the burner 70 further includes a second secondary air structure 74 and a third secondary air structure 75. The second secondary air structure 74 is located on the side of the first pulverized coal burner 71 away from the second pulverized coal burner 72, and the third secondary air structure 75 is located on the side of the second pulverized coal burner 72 away from the first pulverized coal burner 71. This arrangement allows the burner to control the air distribution entering the boiler 20. The airflow of the second secondary air structure 74 and the third secondary air structure 75 can be independently adjusted to provide the most suitable airflow for pulverized coal particles of different sizes, promoting their complete combustion. This not only improves combustion efficiency but also enhances the flexibility of the boiler system, enabling rapid adjustment of the burner's air intake strategy according to changes in the operating conditions of the boiler 20, ensuring stable and efficient combustion within the boiler 20 under rapid load changes or low-load stable combustion conditions.

[0070] like Figure 5 and Figure 6As shown, in some embodiments, the first secondary air structure 73 has a first secondary air nozzle 731, the second secondary air structure 74 has a second secondary air nozzle 741, and the third secondary air structure 75 has a third secondary air nozzle 751. The flow area of ​​the first secondary air nozzle 731 is larger than that of the second secondary air nozzle 741, and the flow area of ​​the first secondary air nozzle 731 is larger than that of the third secondary air nozzle 751. This configuration, by controlling the flow areas of the first secondary air nozzle 731, the second secondary air nozzle 741, and the third secondary air nozzle 751, achieves regulation of the pulverized coal airflow. Specifically, the first secondary air nozzle 731 helps to promote the smooth separation and transmission of large pulverized coal particles, while the second secondary air nozzle 741 and the third secondary air nozzle 751 are beneficial for the control and distribution of small pulverized coal particles. This setup effectively ensures that large and small pulverized coal particles are properly proportioned and supplied in a timely manner under various operating conditions. This not only improves the combustion stability of the coal-fired boiler at low loads but also significantly enhances its responsiveness and flexibility under rapid load changes.

[0071] Furthermore, by adjusting the flow areas of the first secondary air nozzle 731, the second secondary air nozzle 741, and the third secondary air nozzle 751, the combustion process can be further guaranteed, coal powder waste can be reduced, and combustion efficiency can be improved.

[0072] like Figure 7 and Figure 8 As shown, in some embodiments, the particle size separation device 30 employs a vibration separation structure, a gravity settling separation structure, or a flow separation structure. This design effectively separates pulverized coal particles of different sizes, thus providing a more flexible combustion scheme for coal-fired boilers across a wide load range. Through gravity settling separation, pulverized coal is naturally classified according to particle size in the vertical direction; while flow separation utilizes the size differences of pulverized coal during flow to achieve separation within a specific flow channel. Both separation methods can effectively classify pulverized coal particles, providing a foundation for multi-stage combustion in subsequent burners.

[0073] The particle size separation device 30 is used to separate coal powder particles of different sizes. The separation methods include, but are not limited to, gravity sedimentation separation and flow separation. This section only describes gravity sedimentation separation and flow separation in detail. Other separation methods, such as vibration separation (Brazil fruit effect), can also achieve or partially achieve similar effects.

[0074] Typical gravity sedimentation separation, such as Figure 7 and Figure 8As shown, in a rectangular gravity settling chamber, mixed-size pulverized coal particles are ejected from a pulverized coal nozzle at a certain horizontal velocity v, undergoing free settling motion. The settling velocity of the pulverized coal particles is related to their diameter. The settling velocity v can be obtained using Stokes' theorem. t The relationship with particle size d is as follows:

[0075]

[0076] Where v t ρ is the settling velocity, in m / s. g is the acceleration due to gravity, approximately 9.8 m / s². d is the diameter of the particle, in meters (m). Particle density, kg / m³. It is the density of the fluid, kg / m³. It is the dynamic viscosity of the fluid, and its unit is Pa·s.

[0077] In another embodiment, when mixed-size coal powder particles fall freely from a height to the inclined chute, the mixed particles will move downward along the inclined chute. During the movement, the mixed particles will undergo size separation under the drive of gravity, with small particles gathering on the left and large particles appearing on the right, thereby achieving the separation of large and small particles.

[0078] like Figures 1 to 4 As shown, in some embodiments, the boiler system further includes a first pulverizer 81 and a second pulverizer 82. The first pulverizer 81 is installed on the third pipeline 103, and the second pulverizer 82 is installed on the fifth pipeline 105. The first pulverizer 81, installed on the third pipeline 103, supplies pulverized coal to the first coal bunker 40, while the second pulverizer 82, installed on the fifth pipeline 105, supplies pulverized coal to the second coal bunker 50. This arrangement allows the boiler system to control the supply amount and particle size of pulverized coal under different operating conditions, thereby optimizing combustion efficiency and improving the flexibility and stable combustion capability of the coal-fired boiler.

[0079] Specifically, the technical solution of this embodiment has conventional operating conditions, rapid load change conditions, wide load stable combustion conditions, and wide load stable combustion flexible operating conditions.

[0080] Under normal operating conditions, the coal mill 10 continuously generates pulverized coal, which enters the boiler 20 for combustion through the first pipeline 101 and the burner 70. The pulverized coal mixing device 83, the first coal bunker 40, the second coal bunker 50, and the pulverized coal distribution device 60 are not activated.

[0081] For rapidly changing load conditions, such as Figure 3As shown, due to the limitations of rapid grinding in the coal mill 10, it cannot meet the coal feeding requirements of the boiler 20 under rapid load changes. In addition to the coal powder flow rate Q1 generated by the coal mill 10, an additional coal powder flow rate Q2 generated in the second coal bunker 50 is added. The two are mixed in the coal powder mixing device 83 and then enter the boiler 20 through the burner 70 at a flow rate of Q1+Q2, achieving rapid coal feeding and meeting the coal feeding requirements under rapid load changes. Another stream of coal powder generated by the coal mill 10 enters the particle size separation device 30. Larger particles after separation enter the second coal bunker 50 under the action of the second feeder 82, ensuring the amount of coal powder in the second coal bunker 50. The first coal bunker 40 is not used.

[0082] For stable combustion under wide load conditions, such as Figure 2 As shown, considering the decrease in furnace temperature under low load, the heat required for ignition of the pulverized coal gas flow (ignition heat) is relatively insufficient. Using small-sized pulverized coal particles makes successful ignition at lower furnace temperatures possible. Under this condition, small-particle pulverized coal in the first coal bunker 40 is fed to the pulverized coal distribution device 60 via the third feeder. Pulverized coal generated by the pulverizing mechanism 10 also enters the pulverized coal distribution device 60. The pulverized coal distribution device 60 adjusts the output of two or more pulverized coal output streams, which are then fed into the burner 70 and into the boiler 20 for combustion. One small-sized pulverized coal output stream enters the corresponding pulverized coal port of the burner 70, while the pulverized coal generated by the pulverizing mechanism 10 enters the other pulverized coal ports of the burner 70. The small-sized pulverized coal output stream ignites rapidly and drives the pulverized coal output streams of other ports to ignite, achieving stable combustion under low load.

[0083] For flexible operating conditions with stable combustion under wide loads, such as Figure 1 As shown, the pulverized coal flow rate Q1 generated by the coal mill 10 enters the pulverized coal mixing device 83 through the first pipeline 101. The pulverized coal stored in the second coal bunker 50 also enters the pulverized coal mixing device 83 at a flow rate Q2. The mixed pulverized coal then enters the pulverized coal distribution device 60 at a flow rate of Q1+Q2 to meet the feeding requirements for rapid load changes. Small pulverized coal particles in the first coal bunker 40 are fed to the pulverized coal distribution device 60 via the third feeder. The pulverized coal distribution device 60 adjusts and outputs two or more pulverized coal output streams, which are then fed into the burner 70 and sent to the boiler 20 for combustion. One small-sized pulverized coal output stream enters the corresponding pulverized coal port of the burner 70, while the other pulverized coal with a flow rate of Q1+Q2 passes through the pulverized coal ports of other burners 70. The small-sized pulverized coal output stream ignites quickly and drives the pulverized coal output streams of other pulverized coal ports to ignite, achieving stable and flexible combustion under wide loads. Different sized pulverized coal output streams correspond to different pulverized coal ports. Another stream of pulverized coal generated by the pulverizing mechanism 10 enters the particle size separation device 30. The larger particles after separation enter the second coal bunker 50 under the action of the second feeder 82, and the smaller particles after separation enter the first coal bunker 40 under the action of the first feeder 81.

[0084] According to a second aspect of this application, a boiler combustion control method is provided to control the aforementioned boiler system, such as... Figure 9 As shown, the boiler combustion control method in this embodiment includes: controlling the boiler system to be in a first working mode;

[0085] When the boiler system is in the first working mode, the first coal powder generated by the coal milling mechanism 10 enters the particle size separation device 30, and the separated first coal powder is transported to the first coal bunker 40. The first coal powder in the first coal bunker 40 and the second coal powder generated by the coal milling mechanism 10 are then transported to the boiler 20.

[0086] The first pulverized coal produced by the coal mill 10 is separated by the particle size separator 30 and transported to the first coal bunker 40. By transporting the smaller-sized first pulverized coal in the first coal bunker 40 and the second pulverized coal directly produced by the coal mill 10 into the boiler 20 for combustion, the boiler's stable combustion capability under low load conditions is enhanced. This setup utilizes the easy ignition characteristic of small-sized pulverized coal, significantly reducing the heat required for ignition and ensuring successful ignition of the pulverized coal gas flow even at lower furnace temperatures. Simultaneously, under rapid load changes, the control method can quickly mobilize the smaller-sized pulverized coal stored in the first coal bunker 40 and mix it with the second pulverized coal, avoiding the problem of insufficient pulverization response of the coal mill 10 and realizing the boiler's rapid load change capability.

[0087] According to a third aspect of this application, a boiler combustion control method is provided to control the aforementioned boiler system, such as... Figure 10 As shown, the boiler combustion control method in this embodiment includes: controlling the boiler system to be in a second working mode;

[0088] When the boiler system is in the second working mode, the third coal powder generated by the coal mill 10 enters the particle size separation device 30. The separated third coal powder is transported to the second coal bunker 50, where the third coal powder in the second coal bunker 50 is mixed with the fourth coal powder generated by the coal mill 10. The mixed third and fourth coal powders are then transported to the boiler 20.

[0089] The third type of pulverized coal produced by the pulverizing mechanism 10 first enters the particle size separation device 30. After particle size separation, the third type of pulverized coal is conveyed to the second coal bunker 50. Subsequently, the third type of pulverized coal in the second coal bunker 50 is mixed with the fourth type of pulverized coal newly produced by the pulverizing mechanism 10, and finally the mixed pulverized coal is conveyed to the boiler 20 for combustion. This method ensures that when the boiler needs to respond quickly to load changes, it can provide pre-treated pulverized coal that meets specific combustion requirements in a timely manner, thereby overcoming the limitation of slow dynamic response of the pulverizer, enhancing the boiler's flexible peak-shaving capability, and achieving high efficiency and stability in the operation of the coal-fired boiler.

[0090] According to a fourth aspect of this application, a boiler combustion control method is provided to control the aforementioned boiler system, such as... Figure 11 As shown, the boiler combustion control method in this embodiment includes: controlling the boiler system to be in a third working mode;

[0091] When the boiler system is in the third working mode, the fifth coal powder generated by the coal mill 10 enters the particle size separation device 30. The particle size separation device 30 separates the fifth coal powder into the sixth coal powder and the seventh coal powder. The sixth coal powder is transported to the first coal bunker 40, and the seventh coal powder is transported to the second coal bunker 50. The seventh coal powder in the second coal bunker 50 is mixed with the eighth coal powder generated by the coal mill 10. The mixed seventh coal powder and the eighth coal powder are then transported to the boiler 20 along with the sixth coal powder.

[0092] The fifth pulverized coal generated by the pulverizing mechanism 10 is guided to the particle size separation device 30, which finely separates it into sixth and seventh pulverized coal. The sixth pulverized coal is then transferred to the first coal bunker 40 for storage, while the seventh pulverized coal enters the second coal bunker 50. Next, the seventh pulverized coal in the second coal bunker 50 is mixed with the newly generated eighth pulverized coal from the pulverizing mechanism 10 in a pulverized coal mixing device. Finally, the mixed seventh and eighth pulverized coal, along with the sixth pulverized coal, is fed into the boiler 20 for combustion. This method not only optimizes the size distribution of the pulverized coal and improves the flexibility of boiler combustion, but also enhances the boiler system's responsiveness under rapid load changes and stable combustion performance under low load conditions by pre-storing pulverized coal of different particle sizes. The pre-storage and immediate use of small-sized pulverized coal reduces the ignition heat requirement of the pulverized coal, promotes ignition of the pulverized coal at low furnace temperatures, and ensures the continuity and stability of combustion. Meanwhile, the pre-storage of large-sized pulverized coal provides the system with additional pulverized coal reserves, enabling rapid replenishment of pulverized coal supply during rapid load changes. This overcomes the limitations of the pulverizing rate of the coal mill mechanism and achieves efficient and flexible boiler operation.

[0093] In the description of this invention, it should be understood that "a plurality of" means two or more. Directional terms such as "front, back, up, down, left, right," "horizontal, vertical, perpendicular, horizontal," and "top, bottom" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner or outer contours relative to the outline of each component itself.

[0094] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0095] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A boiler system, characterized in that, include: Coal grinding mechanism (10); The boiler (20) is connected to the coal milling mechanism (10) via the first pipeline (101); The particle size separation device (30) is connected to the coal grinding mechanism (10) through the second pipeline (102). The particle size separation device (30) is used to separate coal with a preset particle size. The first coal bunker (40) is connected to the particle size sorting device (30) through the third pipeline (103) so that coal of the preset particle size can enter the first coal bunker (40). The first coal bunker (40) is connected to the boiler (20) through the fourth pipeline (104).

2. The boiler system according to claim 1, characterized in that, The boiler system also includes a second coal bunker (50), which is connected to the particle size sorting device (30) via a fifth pipeline (105). The particle size of the coal in the second coal bunker (50) is larger than that of the coal in the first coal bunker (40). The second coal bunker (50) is connected to the boiler (20) via a sixth pipeline (106).

3. The boiler system according to claim 2, characterized in that, The sixth pipe (106) is connected to the first pipe (101).

4. The boiler system according to claim 2, characterized in that, The boiler system also includes a pulverized coal mixing device (83), which is located at the connection between the sixth pipeline (106) and the first pipeline (101).

5. The boiler system according to claim 2, characterized in that, The boiler system also includes a pulverized coal distribution device (60), which is connected to the boiler (20). The first pipeline (101) and the fourth pipeline (104) are both connected to the pulverized coal distribution device (60).

6. The boiler system according to claim 2, characterized in that, There are multiple first pipelines (101), multiple fourth pipelines (104) and multiple sixth pipelines (106). Multiple first pipelines (101) and multiple sixth pipelines (106) are arranged in a one-to-one correspondence. Multiple feed inlets are provided on the boiler (20). Multiple first pipelines (101), multiple fourth pipelines (104) and multiple feed inlets are connected in a one-to-one correspondence.

7. The boiler system according to claim 6, characterized in that, The plurality of feed inlets are arranged at circumferential intervals along the boiler (20).

8. The boiler system according to claim 6, characterized in that, The boiler system also includes multiple burners (70), each burner (70) is provided in a one-to-one correspondence with a multiple feed inlet, and each burner (70) is connected to a first pipeline (101).

9. The boiler system according to claim 8, characterized in that, The burner (70) includes a first pulverized coal burner (71) and a second pulverized coal burner (72). The first pulverized coal burner (71) has a first coal inlet, and the second pulverized coal burner (72) has a second coal inlet. The first pulverized coal burner (71) is connected to the first pipeline (101), and the second pulverized coal burner (72) is connected to the fourth pipeline (104).

10. The boiler system according to claim 9, characterized in that, The first pulverized coal burner (71) includes a first pulverized coal nozzle (711), and a first blunt body (712) is provided inside the first pulverized coal nozzle (711). The two ends of the first blunt body (712) are connected to the first pulverized coal nozzle (711).

11. The boiler system according to claim 9, characterized in that, The second pulverized coal burner (72) includes a second pulverized coal nozzle (721), and a second blunt body (722) is provided inside the second pulverized coal nozzle (721). The two ends of the second blunt body (722) are connected to the second pulverized coal nozzle (721).

12. The boiler system according to claim 9, characterized in that, The burner (70) also includes a first secondary air structure (73), which is disposed between the first pulverized coal burner (71) and the second pulverized coal burner (72).

13. The boiler system according to claim 12, characterized in that, The burner (70) further includes a second secondary air structure (74) and a third secondary air structure (75). The second secondary air structure (74) is located on the side of the first pulverized coal burner (71) away from the second pulverized coal burner (72), and the third secondary air structure (75) is located on the side of the second pulverized coal burner (72) away from the first pulverized coal burner (71).

14. The boiler system according to claim 13, characterized in that, The first secondary air structure (73) has a first secondary air nozzle (731), the second secondary air structure (74) has a second secondary air nozzle (741), and the third secondary air structure (75) has a third secondary air nozzle (751). The flow area of ​​the first secondary air nozzle (731) is larger than that of the second secondary air nozzle (741), and the flow area of ​​the first secondary air nozzle (731) is larger than that of the third secondary air nozzle (751).

15. The boiler system according to claim 2, characterized in that, The particle size separation device (30) adopts a vibration separation structure, a gravity settling separation structure, or a flow separation structure; and / or, the boiler system further includes a first feeder (81) and a second feeder (82), the first feeder (81) being installed on the third pipeline (103) and the second feeder (82) being installed on the fifth pipeline (105).

16. A boiler combustion control method for controlling the boiler system according to any one of claims 1 to 15, characterized in that, The boiler combustion control method includes: controlling the boiler system to be in a first operating mode; When the boiler system is in the first working mode, the first coal powder generated by the coal grinding mechanism (10) enters the particle size separation device (30), and the separated first coal powder is transported to the first coal bunker (40). The first coal powder in the first coal bunker (40) and the second coal powder generated by the coal grinding mechanism (10) are then transported to the boiler (20).

17. A boiler combustion control method for controlling the boiler system according to any one of claims 2, 3, 5 to 14, characterized in that, The boiler combustion control method includes: controlling the boiler system to a second operating mode; When the boiler system is in the second working mode, the third coal powder generated by the coal grinding mechanism (10) enters the particle size separation device (30), and the separated third coal powder is transported to the second coal bunker (50). The third coal powder in the second coal bunker (50) is mixed with the fourth coal powder generated by the coal grinding mechanism (10), and the mixed third coal powder and the fourth coal powder are transported to the boiler (20).

18. A boiler combustion control method for controlling the boiler system according to any one of claims 2, 3, 5 to 14, characterized in that, The boiler combustion control method includes: controlling the boiler system to a third operating mode; When the boiler system is in the third working mode, the fifth coal powder generated by the coal mill (10) enters the particle size separation device (30), which separates the fifth coal powder into the sixth coal powder and the seventh coal powder. The sixth coal powder is transported to the first coal bunker (40), and the seventh coal powder is transported to the second coal bunker (50). The seventh coal powder in the second coal bunker (50) is mixed with the eighth coal powder generated by the coal mill (10), and the mixed seventh coal powder and the eighth coal powder are transported to the boiler (20) along with the sixth coal powder.

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