Half-capacity storage type / direct blowing type coal pulverizing system, coal pulverizing method and boiler

Abstract

The invention relates to the technical field of boiler transformation, in particular to a half-capacity storage type / direct blowing type coal pulverizing system, a coal pulverizing method and a boiler, pulverized coal treatment paths on the two sides of a coal mill are improved, pulverized coal treated by the coal mill is divided into a direct blowing mode and a storage mode, and when a thermal power generating unit operates at a high load, the pulverized coal is stored in the direct blowing mode. The fuel is directly delivered to a hearth to participate in combustion in a direct blowing mode, and stable load supply is ensured; pulverized coal separated by a coal mill is collected and stored in a storage mode, and when the power demand fluctuates, a proper amount of pulverized coal is extracted and mixed with primary air to participate in combustion according to the load requirement. By means of the coal pulverizing mode, the frequency of frequent starting and stopping of the coal mill can be reduced when the thermal power generating unit operates in a low-load mode, the response speed and flexibility of the thermal power generating unit to load changes are improved, and the economical efficiency and stability of the system are enhanced. The problems that the stability of a thermal power generating unit system is affected and energy consumption is large due to frequent starting and stopping of an existing coal mill are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of boiler transformation, and in particular to a semi-capacity storage type / direct-blowing type powder making system, a powder making method and a boiler. Background Art

[0002] As energy crisis and environmental pollution problems worsen, the development of new energy is receiving more and more attention. As a renewable green energy, new energy has the advantages of being clean, environmentally friendly, sustainable and long-lasting. It has become one of the important choices for people to cope with energy shortages, climate change and energy conservation and emission reduction. As the global energy structure rapidly transforms to low-carbon, the installed capacity of renewable energy is accelerating, especially intermittent renewable energy such as wind power and photovoltaic power generation has become the main force of new global installed capacity. However, new energy power generation has strong volatility and uncertainty. As the installed capacity of new energy generators accounts for an increasing proportion of the local total power capacity, the injection rate of new energy continues to increase. The absorption capacity of new energy is limited. Excess new energy needs to be frequently transmitted to the load center through long-distance transmission lines, which makes new energy have a greater impact on the transient stability of the power system. In order to maintain stability, thermal power generators need to frequently perform peak and frequency regulation operations, and often operate for a long time at loads as low as 30%.

[0003] In the process of thermal power generation, the fuel is first processed by the pulverizing system and ground into fine coal powder. The coal powder is then sent into the furnace of the boiler, mixed with air and burned, releasing a large amount of heat energy to heat the water in the boiler, turning it into high-temperature, high-pressure steam. The steam is used to drive the turbine to rotate, drive the generator to generate electricity, and finally convert mechanical energy into electrical energy. Therefore, the pulverizing system is an important auxiliary system in the thermal power generating unit. When the thermal power generating unit is running at low load, the demand for pulverized coal in the boiler is reduced, which will cause the pulverizing system to start and stop frequently to adapt to the load changes, especially the frequent start and stop of the coal mill in the pulverizing system; the start or stop of the coal mill in a short period of time will consume a lot of plant electricity, which not only increases the cost of power generation, but also aggravates the wear of the equipment and shortens the service life of the equipment; at the same time, the start time of the coal mill is relatively long, which affects the continuity and stability of load regulation to a certain extent. In the process of thermal power generation, the rapid change of load may have an adverse effect on the operating stability of the unit and may even cause safety accidents. Summary of the invention

[0004] In view of the problem in the prior art that low-load operation of thermal power units causes frequent start and stop of coal mills, affecting system stability of thermal power units and high energy consumption, the present invention provides a semi-capacity storage / direct-blowing pulverizing system, pulverizing method and boiler.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a semi-capacity storage type / direct-blowing type pulverizing system, comprising a coal mill and a primary air main pipe; The A side of the coal mill is connected to an A side coal feeder and an A side coarse powder separator, and the B side of the coal mill is connected to a B side coal feeder and a B side coarse powder separator; The coal powder outlet of the B-side coarse powder separator is connected to the B-side burner; The coal powder outlet of the coarse powder separator on the A side is divided into two paths, one of which is connected to the burner on the A side, and the other is connected in sequence to the cyclone separator, the powder bin, the powder feeder and the air-powder mixer; the outlet of the air-powder mixer is connected to the burner on the A side; The primary air main pipe is divided into three routes, the first route is connected to the A side of the coal mill, the second route is connected to the B side of the coal mill, and the third route is connected to the A side burner; the exhaust gas outlet of the cyclone separator is connected to the burnt air layer burner.

[0006] Optionally, an A-side primary air door is provided between the primary air main pipe and the A-side of the coal mill.

[0007] Optionally, a B-side primary air door is provided between the primary air main pipe and the B side of the coal mill.

[0008] Optionally, a powder bin primary air door is provided between the primary air main pipe and the A-side burner.

[0009] Optionally, a powder bin powder delivery door is provided between the air-powder mixer and the A-side burner.

[0010] Optionally, an exhaust gas fan is provided between the cyclone separator and the burnt-out air layer burner.

[0011] Optionally, a bypass powder delivery door is provided between the A-side coarse powder separator and the cyclone separator; and a direct blowing powder delivery door is provided between the A-side coarse powder separator and the A-side burner.

[0012] Optionally, a B-side powder delivery door is provided between the B-side coarse powder separator and the B-side burner.

[0013] A method for making powder using the above-mentioned semi-capacity storage type / direct-blowing type powder making system comprises: When the thermal power unit is running at low load: The coal feeders on the A side and the B side are used to feed coal, and the ground coal powder is carried by primary air into the coarse powder separator on the A side and the coarse powder separator on the B side for separation; The coal powder separated by the coarse powder separator on the A side is dropped into the powder bin for storage through the cyclone separator, and the exhaust gas separated by the cyclone separator is sent to the burnout air layer burner; The coal powder separated by the coarse powder separator on the B side directly enters the burner on the B side to complete the pulverizing; When the thermal power unit is operating at high load or normally: The coal feeders on the A side and the B side are used to feed coal, and the ground coal powder is carried by primary air into the coarse powder separator on the A side and the coarse powder separator on the B side for separation; The coal powder separated by the coarse powder separator on the A side is sent to the air-powder mixer through the cyclone separator, the powder bin and the powder feeder in turn, mixed with the primary air from the primary air main pipe, and sent to the burner on the A side for combustion; The coal powder separated by the coarse powder separator on the B side directly enters the burner on the B side to complete the pulverizing.

[0014] The present invention also provides a boiler, comprising the above-mentioned half-capacity storage type / direct-blowing type powder making system.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a semi-capacity storage type / direct blowing type pulverizing system, which includes a coal mill and a primary air main pipe; the coal powder is separated by arranging coarse powder separators on both sides of the coal mill, and the coal powder outlet of the coarse powder separator on the A side is connected to the burner on the A side and the cyclone separator, the powder bin, the powder feeder and the air-powder mixer respectively, so as to achieve a more detailed separation and storage of the coal powder, ensure that the quality of the coal powder fed into the burner is more uniform, which is helpful to improve the combustion efficiency and reduce the loss caused by incomplete combustion. The design of the burnout air layer burner is helpful to further promote the burnout of the coal powder, reduce the carbon content of the fly ash, and improve the overall energy utilization efficiency. The structure divides the operation of the coal mill into two modes, one of which is the direct blowing mode, that is, the coal powder treated by the coal mill is directly transported to the furnace to participate in the combustion, ensuring the stable supply of the basic load; the other is the storage mode, that is, the coal powder separated by the coal mill is collected by the cyclone separator and stored in the powder bin. When the power demand fluctuates, according to the actual load requirements, an appropriate amount of coal powder can be taken out from the powder bin and mixed with the primary air, and then fed into the furnace for combustion. This pulverizing method can not only reduce the number of frequent starts and stops of coal mills when thermal power units are running at low load, reduce power consumption and equipment wear, but also improve the response speed and flexibility of thermal power units to load changes, and enhance the economy and stability of the system. While ensuring power generation efficiency, it can effectively deal with the problem of unstable power output caused by a high proportion of new energy access to the power grid, and realize efficient and stable operation of thermal power generating units in complex operating environments.

[0016] A side primary air door is provided between the primary air main pipe and the side A of the coal mill. The side A primary air door can accurately control the air volume entering the side A of the coal mill, ensuring that the side A of the coal mill obtains a stable and appropriate amount of air intake, thereby ensuring stable transportation and efficient grinding of coal powder. When the load changes, the coal quality fluctuates, or the coal mill output needs to be adjusted quickly, the side A primary air door can be adjusted to respond quickly and adjust the air volume entering the coal mill to meet the demand of the combustion system for coal powder.

[0017] A B-side primary air door is provided between the primary air main pipe and the B-side of the coal mill. The B-side primary air door can accurately adjust the primary air volume entering the B-side of the coal mill, optimize the operating efficiency of the coal mill, and reduce energy consumption and wear. When the load changes, the coal quality fluctuates, or the coal mill output needs to be adjusted quickly, the B-side primary air door can be adjusted to respond quickly and adjust the air volume entering the coal mill to meet the demand of the combustion system for coal powder.

[0018] A powder bin primary air door is provided between the primary air main pipe and the burner on side A. The powder bin primary air door is mainly used to accurately adjust the coal powder air volume delivered from the powder bin to the burner on side A, to ensure the stability and efficiency of the coal powder during the combustion process, and to optimize the mixing ratio of coal powder and air, thereby improving the combustion efficiency and enhancing the system flexibility.

[0019] A powder bin powder delivery door is provided between the air-powder mixer and the A-side burner. The powder bin powder delivery door can accurately control the amount of pulverized coal delivered from the pulverized coal bin to the A-side burner through the air-powder mixer, while maintaining stable combustion of the burner, optimizing the mixing ratio of pulverized coal and air, thereby improving combustion efficiency, ensuring that pulverized coal is fully burned in the burner, releasing more heat energy, and improving the thermal efficiency of the boiler.

[0020] An exhaust gas fan is arranged between the cyclone separator and the burnout air layer burner. The exhaust gas fan helps the light coal powder airflow separated from the cyclone separator to enter the furnace, realizes the separation of thick and thin coal powder, ensures that the combustion of coal powder in the furnace is more stable, and improves the combustion efficiency. At the same time, when the boiler is running at low load, the exhaust gas fan can adjust the amount of air entering the furnace, thereby optimizing the air distribution, ensuring that the coal powder is fully burned in the furnace, reducing the loss of incomplete combustion, and reducing the emission of pollutants.

[0021] A bypass powder delivery door is provided between the coarse powder separator on the A side and the cyclone separator; a direct blowing powder delivery door is provided between the coarse powder separator on the A side and the burner on the A side. The bypass powder delivery door can flexibly adjust the conveying path of the coal powder, so that part of the coal powder enters the powder bin for storage through the cyclone separator, thereby improving the flexibility of the thermal power unit system. The setting of the direct blowing powder delivery door can directly deliver the coal powder to the burner for combustion when the load of the thermal power unit is high or full load, and cooperate with the bypass powder delivery door to realize the adjustment of pulverizing according to the load of the thermal power unit, reducing the number of start-stop times of the coal mill.

[0022] A B-side powder delivery door is provided between the B-side coarse powder separator and the B-side burner. The B-side powder delivery door can accurately control the amount of pulverized coal delivered from the B-side coarse powder separator to the B-side burner, maintain stable combustion of the burner, ensure that the pulverized coal is fully burned in the burner, and improve combustion efficiency.

[0023] The present invention also provides a method for making powder using the above-mentioned semi-capacity storage type / direct-blowing type powder making system. The method realizes flexible operation of the system by making the coal feeders on the A side and the B side feed coal at the same time when the thermal power unit is running at low load, but adopting different coal powder processing paths. The coal powder on the A side passes through the cyclone separator and falls into the powder bin for storage, while the coal powder on the B side directly enters the burner. This design allows the coal powder on the A side to be stored in the powder bin. When the load of the unit increases, the coal powder can be reused, which not only improves the utilization rate of the coal powder, but also avoids the problem of unstable combustion caused by excessive coal powder at low load. When the thermal power unit is running at high load or normally, the present invention realizes efficient utilization of coal powder by passing the coal powder on the A side through the cyclone separator, the powder bin and the powder feeder, and then sending it to the air-powder mixer to mix with the primary air, and then sending it to the burner. At the same time, the coal powder on the B side still directly enters the burner, ensuring the stability and efficiency of combustion. That is, by flexibly adjusting the coal powder transportation path and optimizing the combustion process, the flexibility and adaptability of the system are enhanced, the coal powder utilization rate and combustion efficiency are improved, and the energy conservation, emission reduction and environmental protection performance are improved. While promoting the efficient, stable and environmentally friendly operation of the thermal power unit, the number of starts and stops of the coal mill is reduced, the loss of the coal mill is reduced, and the economy of the thermal power unit is further improved.

[0024] The present invention also provides a boiler, including the above-mentioned semi-capacity storage / direct-blowing pulverizing system. The boiler can self-adjust according to the operating load of the thermal power unit to adapt to the load adjustment of the thermal power unit. It has good flexibility, long service life, low operation and maintenance costs, low losses, and better economy. It can better respond to and meet the needs of the power grid, which is of great significance for improving the overall economic benefits and market competitiveness of the power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of a half-capacity storage / direct-blowing powder making system of the present invention.

[0026] Figure 2 The present invention is a flow chart of a semi-capacity storage / direct-blowing powder making method.

[0027] Among them, 1- coal mill, 2- primary air door on A side, 3- coal feeder on A side, 4- coarse powder separator on A side, 5- direct blowing powder delivery door, 6- bypass powder delivery door, 7- powder delivery door on B side, 8- coarse powder separator on B side, 9- coal feeder on B side, 10- primary air door on B side, 11- cyclone separator, 12- powder silo, 13- powder feeder, 14- air-powder mixer, 15- powder silo delivery door, 16- exhaust air fan, 17- primary air main pipe, 18- primary air door on powder silo, 19- burnout air layer burner, 20- burner on A side, 21- burner on B side. DETAILED DESCRIPTION

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

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0031] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0032] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0035] Example 1 See also Figure 1 , the present invention provides a semi-capacity storage type / direct-blowing type pulverizing system, comprising a coal mill 1 and a primary air main pipe 17; The A side of the coal mill 1 is connected to an A side coal feeder 3 and an A side coarse powder separator 4, and the B side of the coal mill 1 is connected to a B side coal feeder 9 and a B side coarse powder separator 8; The coal powder outlet of the B-side coarse powder separator 8 is connected to the B-side burner 21; The coal powder outlet of the A-side coarse powder separator 4 is divided into two paths, one of which is connected to the A-side burner 20, and the other is sequentially connected to the cyclone separator 11, the powder bin 12, the powder feeder 13 and the air-powder mixer 14; the outlet of the air-powder mixer 14 is connected to the A-side burner 20; The primary air main pipe 17 is divided into three routes, the first route is connected to the A side of the coal mill 1, the second route is connected to the B side of the coal mill 1, and the third route is connected to the A side burner 20; the exhaust gas outlet of the cyclone separator 11 is connected to the burnt air layer burner 19.

[0036] The system separates the coal powder by setting up coarse powder separators on both sides of the coal mill, and connects the coal powder outlet of the coarse powder separator 4 on the A side to the A side burner 20 and the cyclone separator 11, the powder bin 12, the powder feeder 13 and the air-powder mixer 14, respectively, to achieve more detailed separation and storage of the coal powder, ensure that the quality of the coal powder fed into the burner is more uniform, help improve the combustion efficiency and reduce the loss caused by incomplete combustion, and the design of the burnout air layer burner 19 helps to further promote the burnout of coal powder, reduce the carbon content of fly ash, and improve the overall energy utilization efficiency. The structure divides the operation of the coal mill 1 into two modes, one of which is the direct blowing mode, that is, the coal powder treated by the coal mill 1 is directly transported to the furnace to participate in combustion, ensuring the stable supply of basic load; the other is the storage mode, that is, the coal powder separated by the coal mill 1 is collected by the cyclone separator 11 and stored in the powder bin 12. When the power demand fluctuates, according to the actual load requirements, an appropriate amount of coal powder can be taken out from the powder bin 12 and mixed with the primary air, and then sent to the furnace for combustion. This pulverizing method can not only reduce the number of frequent starts and stops of coal mills when thermal power units are running at low load, reduce power consumption and equipment wear, but also improve the response speed and flexibility of thermal power units to load changes, and enhance the economy and stability of the system. While ensuring power generation efficiency, it can effectively deal with the problem of unstable power output caused by a high proportion of new energy access to the power grid, and realize efficient and stable operation of thermal power generating units in complex operating environments.

[0037] Example 2 See also Figure 1The present invention provides a semi-capacity storage type / direct blowing type pulverizing system, comprising a coal mill 1, a primary air door 2 on the A side, a coal feeder 3 on the A side, a coarse powder separator 4 on the A side, a direct blowing powder delivery door 5, a bypass powder delivery door 6, a powder delivery door 7 on the B side, a coarse powder separator 8 on the B side, a coal feeder 9 on the B side, a primary air door 10 on the B side, a cyclone separator 11, a powder bin 12, a powder feeder 13, an air-powder mixer 14, a powder bin powder delivery door 15, an exhaust air fan 16, a primary air main pipe 17, a powder bin primary air door 18, a burnout air layer burner 19, an A side burner 20 and a B side burner 21; The primary air of the primary air main pipe 17 is divided into three routes, wherein the first route is connected to the primary air door 2 on the A side, the second route is connected to the primary air door 10 on the B side, and the third route is connected to the primary air door 18 on the powder bin; the A and B sides of the coal mill 1 are respectively connected to the A side coal feeder 3 and the B side coal feeder 9, and the coal powder outlet of the coal mill 1 is respectively connected to the A side coarse powder separator 4 and the B side coarse powder separator 8; the outlet of the A side coarse powder separator 4 of the coal mill 1 is a three-way, and a direct blowing powder delivery door 5 and a bypass powder delivery door 6 are respectively provided, the bypass powder delivery door 6 is connected to the cyclone separator 11, and the direct blowing powder delivery door 5 is connected to the A side burner 20 is connected, the top outlet of the cyclone separator outlet 11 is connected to the exhaust gas fan 16, and the exhaust gas fan outlet 16 is connected to the burnout air layer burner 19; the bottom outlet of the cyclone separator 11 is connected to the powder bin 12, the bottom of the powder bin 12 is connected to the powder feeder 13, the outlet of the powder feeder 13 is arranged at the lower part of the air-powder mixer 14, the outlet of the air-powder mixer 14 is connected to the powder bin powder delivery door 15, and the outlet of the air-powder mixer 14 is connected to the A-side burner 20; the coal powder outlet of the B-side coarse powder separator 8 of the coal mill 1 is connected to the B-side powder delivery door 7, and the B-side powder delivery door 7 is connected to the B-side burner 21.

[0038] Powder storage process: The powder delivery air of the coal mill 1 is taken from the primary air main pipe 17, the primary air enters the A side of the coal mill 1 through the A side primary air door 2, the coal powder enters the A side of the coal mill 1 through the A side coal feeder 3, the primary air carries the ground coal powder in the coal mill 1 and enters the A side coarse powder separator 4 and the B side coarse powder separator 8 for separation, the coal powder separated from the B side coarse powder separator 8 is sent to the B side burner 21 through the B side powder delivery door 7, the coal powder separated from the A side coarse powder separator 4 is sent to the cyclone separator 11 through the bypass powder delivery door 6, the coal powder passes through the cyclone separator 11 and falls into the powder bin 12, the separated exhaust gas is discharged from the top of the cyclone separator 11 and is sent to the burnout air layer burner 19 through the exhaust gas fan 16.

[0039] Powder feeding process: the coal powder enters the powder feeder 13 through the top outlet of the powder bin 12, the coal powder is sent to the air-powder mixer 14 through the powder feeder 13, the coal powder is mixed with the primary air from the primary air main pipe 17 in the air-powder mixer 14, and the air-powder mixture is sent to the A-side burner 20 through the powder bin powder feeding door 15.

[0040] Operation mode: The coal mill 1 is a double-inlet and double-outlet coal mill. The coal mill 1 can be operated on one side or both sides. The present invention has the following operation modes: Powder storage operation, which is mainly used in the low-load stage of the unit; the coal powder produced by the coal mill 1 is stored in the powder bin 12, and the coal mill 1 does not need to be shut down, reducing the time and operation steps of starting and stopping the coal mill 1; Direct blowing + direct blowing operation, this operation mode is mainly used in the medium and high load stage of the unit; the pulverized coal produced by the pulverizer 1 is not stored, but all sent to the A-side burner 20 and the B-side burner; Powder storage + direct blowing operation, which is mainly used in the low-load stage of the unit, so that part of the coal powder produced by the pulverizer 1 is stored in the powder bin 12, and part is sent to the B-side burner 21 to enter the furnace for combustion; Powder delivery + direct blowing operation, this operation mode is mainly used in the variable load stage of the unit; the pulverized coal stored in the pulverized coal bin 12 is delivered to the burner 20 on the A side, and the pulverized coal ground by the coal mill 1 is delivered to the burner 21 on the B side to enter the furnace to participate in combustion, and the pulverized coal on the A side of the coal mill 1 is not pulverized; Double-side powder delivery / direct blowing + direct blowing operation. This operation mode is mainly used in the high load stage and variable load stage of the unit. The coal powder ground by the pulverizer 1 is delivered to the A-side burner 20 and the B-side burner 21, and the coal powder in the powder bin 12 is also delivered to the A-side burner 20, thereby improving the top load capacity of the unit.

[0041] In actual application, the operation mode can be adaptively selected according to the load and regulation of the thermal power unit, so as to achieve the purpose of matching the operation of the thermal power unit, avoid frequent start and stop of the coal mill 1, reduce the power generation cost and equipment wear, and improve the continuity and stability of load regulation.

[0042] See also Figure 2 The present invention provides a method for making powder using the above-mentioned semi-capacity storage type / direct blowing type powder making system, comprising: When the thermal power unit is running at low load: S11: The coal feeder 3 on the A side and the coal feeder 9 on the B side feed coal, and the ground coal powder is carried by primary air into the coarse powder separator 4 on the A side and the coarse powder separator 8 on the B side for separation; S12: The coal powder separated by the coarse powder separator 4 on the A side is dropped into the powder bin 12 for storage through the cyclone separator 11, and the exhaust gas separated by the cyclone separator 11 is sent to the burnout air layer burner 19; S13: The pulverized coal separated by the coarse powder separator 8 on the B side directly enters the burner 21 on the B side to complete pulverizing; When the thermal power unit is operating at high load or normally: S21: The coal feeder 3 on the A side and the coal feeder 9 on the B side feed coal, and the ground coal powder is carried by primary air into the coarse powder separator 4 on the A side and the coarse powder separator 8 on the B side for separation; S22: The pulverized coal separated by the coarse powder separator 4 on the A side is sent to the air-powder mixer 14 through the cyclone separator 11, the powder bin 12 and the powder feeder 13, and mixed with the primary air from the primary air main pipe 17, and then sent to the burner 20 on the A side for combustion; S23: The pulverized coal separated by the coarse powder separator 8 on the B side directly enters the burner 21 on the B side to complete pulverizing.

[0043] This method improves the utilization rate and combustion efficiency of pulverized coal by flexibly adjusting the coal powder conveying path and optimizing the combustion process, thereby enhancing the flexibility and adaptability of the system, improving the utilization rate and combustion efficiency of pulverized coal, improving energy conservation, emission reduction and environmental protection performance, and enhancing the stability and reliability of the thermal power unit system. It promotes the efficient, stable and environmentally friendly operation of the thermal power unit, while reducing the start and stop times of the coal mill, reducing the loss of the coal mill, and further improving the economy of the thermal power unit.

[0044] The present invention also provides a boiler, including the above-mentioned semi-capacity storage / direct-blowing pulverizing system. The boiler can self-adjust according to the operating load of the thermal power unit to adapt to the load adjustment of the thermal power unit. It has good flexibility, long service life, low operation and maintenance costs, low losses, and better economy. It can better respond to and meet the needs of the power grid, which is of great significance for improving the overall economic benefits and market competitiveness of the power plant.

[0045] In summary, the present invention provides a semi-capacity storage / direct-blowing pulverizing system, pulverizing method and boiler, which are intended to optimize the performance of thermal power generating units under low load and variable load conditions, by dividing the operation of the coal mill 1 into a direct blowing mode and a storage mode. The direct blowing mode is to directly transport the pulverized coal processed by the coal mill to the furnace to participate in combustion, thereby ensuring a stable supply of basic load; the storage mode is that the pulverized coal separated by the coal mill 1 is collected by a cyclone separator 11 and stored in a pulverized coal bin 12. When the power demand fluctuates, an appropriate amount of pulverized coal can be taken out from the pulverized coal bin 12 according to the actual load requirements, mixed with the primary air, and then sent to the furnace for combustion. This method not only reduces the number of frequent starts and stops of the coal mill 1, reduces the power consumption of the plant and the wear of the equipment, but also improves the response speed and flexibility of the unit to load changes, and enhances the economy and stability of the system.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and substitutions, and these modifications and substitutions are also within the scope of protection covered by the claims.

Claims

1. A semi-capacity storage / direct-blowing powder making system, characterized in that: It includes a coal mill (1) and a primary air main pipe (17); The A side of the coal mill (1) is connected to an A side coal feeder (3) and an A side coarse powder separator (4), and the B side of the coal mill (1) is connected to a B side coal feeder (9) and a B side coarse powder separator (8); The coal powder outlet of the B-side coarse powder separator (8) is connected to the B-side burner (21); The coal powder outlet of the A-side coarse powder separator (4) is divided into two paths, one of which is connected to the A-side burner (20), and the other is connected in sequence to the cyclone separator (11), the powder bin (12), the powder feeder (13) and the air-powder mixer (14); the outlet of the air-powder mixer (14) is connected to the A-side burner (20); The primary air main pipe (17) is divided into three paths, the first path is connected to the A side of the coal mill (1), the second path is connected to the B side of the coal mill (1), and the third path is connected to the A side burner (20); the exhaust gas outlet of the cyclone separator (11) is connected to the burnt air layer burner (19).

2. The semi-capacity storage / direct-blowing powder making system according to claim 1, characterized in that: An A-side primary air door (2) is provided between the primary air main pipe (17) and the A-side of the coal mill (1).

3. The semi-capacity storage type / direct-blowing type powder making system according to claim 1, characterized in that: A B-side primary air door (10) is provided between the primary air main pipe (17) and the B-side of the coal mill (1).

4. The semi-capacity storage type / direct-blowing type powder making system according to claim 1, characterized in that: A powder bin primary air door (18) is provided between the primary air main pipe (17) and the A-side burner (20).

5. The semi-capacity storage type / direct-blowing type powder making system according to claim 1, characterized in that: A powder bin powder delivery door (15) is provided between the air-powder mixer (14) and the A-side burner (20).

6. The semi-capacity storage / direct-blowing powder making system according to claim 1, characterized in that: An exhaust gas fan (16) is provided between the cyclone separator (11) and the burnt-out air layer burner (19).

7. The semi-capacity storage type / direct-blowing type powder making system according to claim 1, characterized in that: A bypass powder delivery door (6) is provided between the A-side coarse powder separator (4) and the cyclone separator (11); and a direct blowing powder delivery door (5) is provided between the A-side coarse powder separator (4) and the A-side burner (20).

8. The semi-capacity storage type / direct-blowing type powder making system according to claim 1, characterized in that: A B-side powder delivery door (7) is provided between the B-side coarse powder separator (8) and the B-side burner (21).

9. A method for making powder using the semi-capacity storage type / direct-blowing type powder making system according to any one of claims 1 to 8, characterized in that: include: When the thermal power unit is running at low load: The A-side coal feeder (3) and the B-side coal feeder (9) feed coal, and the ground coal powder is carried by primary air to enter the A-side coarse powder separator (4) and the B-side coarse powder separator (8) for separation; The coal powder separated by the coarse powder separator (4) on the A side is dropped into the powder bin (12) for storage through the cyclone separator (11), and the exhaust gas separated by the cyclone separator (11) is sent to the burnout air layer burner (19); The pulverized coal separated by the coarse powder separator (8) on the B side directly enters the burner (21) on the B side to complete pulverizing; When the thermal power unit is operating at high load or normally: The A-side coal feeder (3) and the B-side coal feeder (9) feed coal, and the ground coal powder is carried by primary air to enter the A-side coarse powder separator (4) and the B-side coarse powder separator (8) for separation; The coal powder separated by the coarse powder separator (4) on the A side is sent to the air-powder mixer (14) through the cyclone separator (11) and the powder bin (12) and the powder feeder (13) in sequence to be mixed with the primary air from the primary air main pipe (17) and then sent to the burner (20) on the A side to participate in combustion; The coal powder separated by the coarse powder separator (8) on the B side directly enters the burner (21) on the B side to complete the pulverizing process.

10. A boiler comprising the semi-capacity storage / direct-blowing pulverizing system according to any one of claims 1 to 8.

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