Coal pulverizing system coupled with external powder bin, coal pulverizing method and boiler

Abstract

The invention relates to the technical field of boiler transformation, in particular to a coal pulverizing system coupled with an external powder bin, a coal pulverizing method and a boiler. An A-side coarse powder separator is arranged on one side of a coal mill, and a B-side coarse powder separator is arranged on the other side of the coal mill; pulverized coal of the A-side coarse powder separator sequentially passes through a cyclone separator, an air locking unloader and an air-powder mixer to enter an A-side combustor; the coal powder of the coarse powder separator on the side B directly enters the combustor, so that two different operation modes of the same coal mill are realized; when a unit operates at a low load, one side of the coal mill operates in a direct blowing manner to ensure a basic load under the condition that the output of the coal mill is not reduced, and the other side of the coal mill performs powder storage operation, powder feeding operation and simultaneous powder storage and feeding operation according to the load requirement of the unit, so that the operation stability of the system is ensured. The problem that in the prior art, a coal pulverizing system is poor in reliability in a low-load state is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of boiler modification, and in particular to a powder making system coupled with an external powder silo, a powder making method and a boiler. Background Art

[0002] As a large number of renewable energy sources, represented by solar and wind energy, are connected to the power grid, existing coal-fired boilers will play a new role in the new power system. On the one hand, they will be required to reduce load as much as possible when renewable energy is sufficient to make room for renewable energy; on the other hand, they can quickly increase load to ensure power supply when renewable energy is insufficient. Therefore, this requires existing coal-fired boilers to improve their operating flexibility and have deep adjustment capabilities to reduce the occurrence of problems in the grid connection and absorption of large-scale new energy power.

[0003] Numerous studies have shown that boiler unit flexibility can be improved through technical measures such as optimizing the coordination between the power plant's coal mill and burner, optimizing the burner to reduce minimum combustion power, and installing a pulverized coal silo. Optimizing the design of the pulverizing system has long been a key component in improving boiler operational flexibility. Improving the economic efficiency, reliability, and adaptability of the pulverizing system to various coal types and loads, improving boiler combustion stability and efficiency, and enhancing the adaptability of thermal power plants to various coal types and loads, operational reliability, and energy conservation and emission reduction are all of great practical significance. Pulverizing system optimization encompasses optimization of the pulverized coal separator, capacity expansion optimization, separator outlet flow field optimization, and pulverizer control mode optimization. Adding an intermediate pulverized coal storage silo within the capacity expansion optimization scheme is a relatively economical and flexible option. The intermediate pulverized coal storage silo can accommodate excess pulverized coal produced by the pulverizer and, when needed, can serve as a backup pulverized coal supply to the pulverizer. It can also simultaneously supply pulverized coal to the pulverizer to assist in carrying the unit load, improving the unit's load response rate.

[0004] At present, most units’ pulverizing systems are of positive pressure direct blowing type. The operation of the pulverizer directly affects the operating conditions of the boiler, resulting in low system reliability and large load adjustment lag. With the high proportion of new energy power systems connected to the grid, it is becoming more and more common for thermal power generating units to operate at 30% load for a long time. When the unit is at 30% load, in order to ensure the unit’s rapid load increase and safety at 30% load, the number of pulverizers in operation in the pulverizing system is small. If any pulverizer fails or is blocked by coal, it is very easy to cause unit load fluctuations and low system reliability. When the unit is running at 30% load, the operation of multiple pulverizers is also not conducive to nitrogen oxides (NO X ) emission control. Therefore, optimizing the performance of the milling system at 30% load becomes a key issue. Summary of the Invention

[0005] In view of the problem of poor reliability of the powder making system under low load state in the prior art, the present invention provides a powder making system coupled with an external powder silo.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a pulverizing system coupled with an external pulverizing silo, comprising a coal mill, wherein an A-side coarse powder separator and an A-side coal feeder are provided on one side of the coal mill, and a B-side coarse powder separator and a B-side coal feeder are provided on the other side of the coal mill; the A-side coarse powder separator and the B-side coarse powder separator are both connected to a primary air main pipe; The pulverized coal outlet of the coarse powder separator on side A is connected in sequence to a cyclone separator, an air lock discharger, an air-powder mixer and a burner on side A; the air-powder mixer is connected to the primary air main pipe; the exhaust gas outlet of the cyclone separator is divided into two routes, one of which is connected to a high-position burner and the other is connected to the air-powder mixer; The pulverized coal outlet of the B-side coarse powder separator is connected to a burner.

[0007] Optionally, a side A bypass damper and a side A capacity damper are provided between the air supply end of the primary air main pipe and the side A coarse powder separator, and the side A bypass damper and the side A capacity damper are connected in parallel.

[0008] Optionally, a B-side bypass damper and a B-side capacity damper are provided between the air supply end of the primary air main pipe and the B-side coarse powder separator, and the B-side bypass damper and the B-side capacity damper are connected in parallel.

[0009] Optionally, the pulverized coal outlet of the A-side coarse powder separator is connected to the cyclone separator via a pulverized coal collecting pipe.

[0010] Optionally, the pulverized coal outlet of the A-side coarse powder separator is provided with an A-side outlet valve.

[0011] Optionally, the pulverized coal outlet of the B-side coarse powder separator is provided with a B-side outlet valve.

[0012] Optionally, the exhaust gas outlet of the cyclone separator is provided with a dust exhaust fan.

[0013] Optionally, an exhaust gas powder delivery valve A is provided between the exhaust gas outlet of the cyclone separator and the air-powder mixer; a exhaust gas powder delivery valve B is provided between the exhaust gas outlet of the cyclone separator and the high-position burner; and a powder delivery valve is provided between the primary air main pipe and the air-powder mixer.

[0014] A method for producing powder using the above-mentioned powder producing system coupled with an external powder silo comprises: When the unit is running at low load: Stop the coal feeder on side A from delivering pulverized coal, and enable the coal feeder on side B to deliver pulverized coal according to the load demand; A part of the air from the primary air main pipe carries the pulverized coal from the coal mill into the coarse powder separator on the A side for separation; The fine powder separated by the coarse powder separator on the A side is transported to the cyclone separator, and after cyclone separation, it falls into the pulverized coal bin for storage, and the exhaust gas from the cyclone separator is sent to the high-position burner for combustion; The other part of the air from the primary air main pipe carries the pulverized coal from the pulverizer into the coarse powder separator on the B side for separation, and then the separated fine powder is transported to the burner for combustion, thus completing the pulverization process. When the unit is under high load or in normal operation: Make the coal feeders on the A side and the B side deliver pulverized coal at the same time according to the load demand; A part of the air from the primary air main pipe carries the pulverized coal from the coal mill into the coarse powder separator on the A side for separation; The fine powder separated by the coarse powder separator on side A is transported to the burner on side A through the cyclone separator, air lock discharger and air-powder mixer in sequence for combustion; Another part of the air from the primary air main pipe carries the coal powder ground by the pulverizer into the coarse powder separator on the B side for separation, and then the separated fine powder is transported to the burner to participate in combustion, completing the pulverizing process.

[0015] A boiler comprises the above-mentioned powder making system coupled with an external powder bin.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a pulverizing system coupled with an external pulverizing bin. The system arranges a side A coarse powder separator on one side of the coal mill and a side B coarse powder separator on the other side; the coal powder of the side A coarse powder separator enters the side A burner in sequence through a cyclone separator, an air lock discharger, and an air-powder mixer; the coal powder of the side B coarse powder separator directly enters the burner, thereby realizing two different operation modes of the same coal mill; when the unit is running at low load, the coal mill can be operated in a direct-blowing mode on one side to ensure the basic load without reducing the output of the coal mill, and the coal mill can be operated in a powder storage mode, a powder delivery mode, and a powder storage and delivery mode according to the load demand of the unit to ensure the stability of the system operation; the system has a simple structure, flexible and changeable operation modes, and low modification cost, and can ensure that coal powder is quickly fed into the unit, ensure the unit load and increase the unit load change rate. At the same time, the coal mill can always operate at the most economical load, thereby improving the adaptability of the boiler to coal types and loads. In addition, the coarse powder separator on side A uses exhaust gas to deliver powder, and there is no exhaust gas involved in the recirculation in the pulverizer cylinder. The pulverizer always operates at the optimal ventilation volume, which is more economical. At the same time, because there is no low-temperature exhaust gas entering the pulverizer, the pulverizer has a strong drying output, which meets the full-output operation requirements of high-moisture coal.

[0017] A side A bypass damper and a side A capacity damper are provided between the air supply end of the primary air main pipe and the side A coarse powder separator, and the side A bypass damper and the side A capacity damper are connected in parallel. The side A bypass damper can adjust the air volume entering the side A coarse powder separator, allowing the system to flexibly adjust the air volume according to factors such as coal type and load changes, thereby optimizing the separation effect and combustion efficiency of coal powder. The side A capacity damper is mainly used to control the total air volume entering the pulverizing system to ensure stable operation of the system. When the bypass damper is open, the capacity damper can be adjusted accordingly to maintain the balance and stability of the system air volume.

[0018] A B-side bypass damper and a B-side capacity damper are installed between the primary air main duct's air supply end and the B-side coarse powder separator. These dampers are connected in parallel. This parallel arrangement allows the system to flexibly adjust the air volume entering the B-side coarse powder separator based on actual needs, enabling rapid air volume adjustment and helping to maintain system stability and efficiency.

[0019] The coal dust outlet of the A-side coarse powder separator is connected to the cyclone separator via a coal dust collection pipe. This pipe, serving as a bridge between the A-side coarse powder separator and the cyclone separator, effectively collects coal dust discharged from the A-side coarse powder separator outlet. The cyclone separator, connected to the coal dust collection pipe, further separates and purifies the coal dust, improving its quality and purity. This helps reduce pollutant emissions during combustion, improves combustion efficiency, and reduces energy consumption.

[0020] The coal powder outlet of the A-side coarse powder separator is provided with an A-side outlet valve. The setting of the A-side outlet valve can more flexibly control and adjust the coal powder flow at the A-side coarse powder separator outlet, further improving the flexibility of the system.

[0021] The coal powder outlet of the B-side coarse powder separator is provided with a B-side outlet valve. The setting of the B-side outlet valve can more flexibly control and adjust the coal powder flow at the B-side coarse powder separator outlet, further improving the flexibility of the system.

[0022] The exhaust gas outlet of the cyclone separator is equipped with a pulverized coal exhaust fan. The exhaust gas separated by the cyclone separator is extracted from the cyclone separator outlet and transported to the subsequent high-level burner or air-pulverized coal mixer. The exhaust gas exhaust fan ensures timely and effective exhaust, preventing accumulation within the cyclone separator and improving the efficiency of pulverized coal transportation.

[0023] An exhaust gas powder delivery valve (A) is installed between the exhaust gas outlet of the cyclone separator and the air-powder mixer; an exhaust gas powder delivery valve (B) is installed between the exhaust gas outlet of the cyclone separator and the high-position burner; and a powder delivery valve is installed between the primary air main pipe and the air-powder mixer. The arrangement of these exhaust gas powder delivery valves (A), B, and the powder delivery valve allows for flexible adjustment of the pulverized coal flow rate entering the air-powder mixer and high-position burner based on combustion requirements, helping to optimize the combustion process and ensure stable equipment operation.

[0024] The present invention provides a pulverizing method using the pulverizing system coupled with an external pulverizing bin. When the unit is running at low load, the coal feeder on side A stops feeding pulverizing, thereby changing the operation mode of side A of the pulverizer to a pulverized coal storage mode, storing the pulverized coal separated on side A of the pulverizer in the pulverized coal bin, and allowing the exhaust gas to participate in the combustion. At the same time, the coal feeder on side B is made to feed pulverized coal for combustion according to the load demand, thereby ensuring the stable operation of the pulverizer and avoiding the impact of the operation of the pulverizer on the operation of the boiler, thereby improving the reliability of the system. When the unit is at high load or operating normally, the coal feeders on side A and side B are made to feed pulverized coal for combustion according to the load demand at the same time, thereby realizing the system's bilateral parallel processing capability, improving the overall flexibility and efficiency of the pulverizing system, adjusting the working status of both sides according to actual needs, optimizing resource allocation, and ensuring the continuity and stability of the pulverizing process.

[0025] A boiler comprising the aforementioned pulverizing system coupled with an external pulverizing silo has good combustion stability, high combustion efficiency, and low operating costs, and is of great significance for solving the problem of large-scale new energy power grid integration and consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The figure is a structural schematic diagram of a powder making system coupled with an external powder silo according to the present invention.

[0027] Figure 2 The present invention is a flow chart of a powder making method of a powder making system coupled with an external powder silo.

[0028] Among them, 1- coal mill, 2-A side bypass damper, 3-A side capacity damper, 4-A side coal feeder, 5- coal powder silo, 6- cyclone separator, 7- pulverized powder exhaust fan, 8- air lock discharger, 9-A exhaust gas pulverized powder feeding valve, 10- pulverized powder feeding valve, 11- burner, 12- primary air main pipe, 13-A side outlet valve, 14- coal powder collecting pipe, 15-B side outlet valve, 16-B side coal feeder, 17-B side bypass damper, 18-B side capacity damper, 19-B exhaust gas pulverized powder feeding valve, 20- high position burner, 21-A side coarse powder separator, 22-B side coarse powder separator, 23-A side burner, 24- air-powder mixer. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only 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 herein can be arranged and designed in various different configurations.

[0030] 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 as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0031] 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, it does not need to be further defined or explained in subsequent drawings.

[0032] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the inventive product is typically placed when in use. These terms are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] 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", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0035] The present invention will be further described in detail below with reference to specific embodiments, which are intended to explain the present invention rather than to limit it.

[0036] See also Figure 1 The present invention provides a pulverizing system coupled with an external pulverizing silo, comprising a coal mill 1, wherein an A-side coarse powder separator 21 and an A-side coal feeder 4 are provided on one side of the coal mill 1, and a B-side coarse powder separator 22 and a B-side coal feeder 16 are provided on the other side of the coal mill 1; the A-side coarse powder separator 21 and the B-side coarse powder separator 22 are both connected to a primary air main pipe 12; The pulverized coal outlet of the A-side coarse powder separator 21 is sequentially connected to the cyclone separator 6, the air lock discharger 8, the air-powder mixer 24, and the A-side burner 23; the air-powder mixer 24 is connected to the primary air main pipe 12; the exhaust gas outlet of the cyclone separator 6 is divided into two paths, one of which is connected to the high-level burner 20, and the other is connected to the air-powder mixer 24; The pulverized coal outlet of the B-side coarse powder separator 22 is connected to the burner 11 .

[0037] The system realizes two different operation modes of the same coal mill by setting a side A coarse powder separator 21 on one side of the coal mill and a side B coarse powder separator 22 on the other side; the coal powder in the side A coarse powder separator 21 enters the side A burner 23 in sequence through the cyclone separator 6, the air lock discharger 8, and the air-powder mixer 24; and the coal powder in the side B coarse powder separator 22 directly enters the burner 11; when the unit is running at low load, the coal mill can be operated in direct blowing mode on one side to ensure the basic load without reducing the output of the coal mill, and the other side of the coal mill can be operated in powder storage mode, powder delivery mode, and powder storage and delivery mode according to the load demand of the unit to ensure the stability of the unit operation. At the same time, the operation mode of side A can be flexibly adjusted to improve the stability of the unit operation and the economy of the coal mill 1.

[0038] Example 2 See also Figure 1 The present invention provides a pulverizing system coupled with an external pulverized coal silo, comprising a coal mill 1, an A-side bypass damper 2, an A-side capacity damper 3, an A-side coal feeder 4, a pulverized coal silo 5, a cyclone separator 6, a pulverized coal exhaust fan 7, an air-locking discharger 8, an A-side exhaust gas pulverized coal feeding valve 9, a pulverized coal feeding valve 10, a burner 11, a primary air main pipe 12, an A-side outlet valve 13, a pulverized coal collecting pipe 14, a B-side outlet valve 15, a B-side coal feeder 16, a B-side bypass damper 17, a B-side capacity damper 18, a B-side exhaust gas pulverized coal feeding valve 19, a high-position burner 20, an A-side coarse powder separator 21, a B-side coarse powder separator 22, an A-side burner 23, and an air-pulverized coal mixer 24. The pulverized coal air for the coal mill 1 is taken from the primary air main pipe 12. The coal is fed to the A side of the coal mill 1 by the A side coal feeder 4, and the air is supplied by the A side bypass damper 2 and the A side capacity damper 3. The coal is fed to the B side of the coal mill 1 by the B side coal feeder 16, and the air is supplied by the B side bypass damper 17 and the B side capacity damper 18. After the coal is ground into powder by the coal mill 1, it is fed to the A side coarse powder separator 21 and the B side coarse powder separator 22 respectively. The coal separated by the A side coarse powder separator 21 is sequentially passed through the A side outlet valve 21 and the coal powder collecting pipe 14. , cyclone separator 6, pulverized coal bin 5, air lock discharger 8 and air-powder mixer 24 deliver powder to A side burner 23 to enter the furnace and participate in combustion. The exhaust gas at the top of the cyclone separator 6 is divided into two paths through the powder exhaust fan 7. One path is delivered to the air-powder mixer 24 through the A exhaust gas powder delivery valve 9 to participate in the powder delivery of the powder bin 5, and the other path is delivered to the high-position burner 20 through the B exhaust gas powder delivery valve 19; the pulverized coal separated by the B side coarse powder separator 22 enters the B side burner 11 through the B side outlet valve 22 to participate in combustion.

[0039] Preferably, to reduce the number of pulverized coal pipeline components, the pulverized coal pipeline at the outlet of the A-side separator 21 can be combined into one, while considering the impact on the separation effect of the A-side separator. Preferably, to reduce the number of pulverized coal pipeline components, the pulverized coal pipeline at the outlet of the A-side coarse powder separator 21 can be combined into one, while considering the impact on the separation effect of the A-side coarse powder separator 21. To reduce the impact of exhaust gas on combustion in the furnace, a bag dust collector can be installed at the exhaust gas outlet of the exhaust fan 7, and the exhaust gas after dust removal is sent to the secondary air main pipe at the air preheater inlet. To improve the pulverized coal separation efficiency, the cyclone separator 6 can be appropriately increased according to the situation.

[0040] Pulverized coal storage process: When the unit needs to store pulverized coal in this coal mill, the coal feeder 4 delivers the raw coal to the coal mill 1, and the primary air in the primary air main pipe 12 enters the coal mill 1 through the A-side bypass damper 2 and the A-side capacity damper 3. The primary air carries the ground coal powder and passes through the A-side coarse powder separator 21 for separation. The separated fine powder is discharged from the A-side outlet valve 13, and then enters the cyclone separator 6 through the coal powder collection pipe 14. After cyclone separation, the coal powder falls into the coal powder bin 5. The exhaust gas at the top of the cyclone separator 6 is pressurized by the powder exhaust fan 7 and then passes through the high-position burner 20 to enter the furnace to participate in combustion or is sent to the air-powder mixer 24.

[0041] Powder feeding process: When the unit needs to feed pulverized coal from the A side of this coal mill, the pulverized coal in the pulverized coal bin 5 passes through the air lock discharger 8 and falls into the air-powder mixer 24. The pulverized coal is mixed with the primary air and fed into the A side burner 23. The primary air comes from the primary air main pipe 12 or the exhaust fan 7 outlet.

[0042] Operation mode: When the unit is under low load, to reduce the amount of pulverized coal input, side A of coal mill 1 stops feeding pulverized coal into the furnace, while side B of coal mill 1 continues or stops feeding pulverized coal according to load demand. At the same time, because the startup and shutdown time of coal mill 1 is relatively long, in order to improve the load response rate of the unit during the load increase phase, coal mill 1 enters a pulverized coal storage program. The pulverized coal is stored in the pulverized coal bin 5 through the cyclone separator 6. The exhaust gas is sent to the high-level burner 20 through the pulverized coal exhaust fan 7 to participate in the furnace combustion. Therefore, coal mill 1 does not need to be stopped and can continue to operate. When the unit is under extremely high load, the pulverized coal bin 5 stores sufficient pulverized coal, and coal mill 1 can continuously supply pulverized coal to the furnace at a high flow rate, improving the load response rate of the unit.

[0043] See also Figure 2 The present invention provides a method for producing powder using the powder producing system coupled with an external powder silo, comprising: When the unit is running at low load: S11: Stop the coal feeder 4 on the A side from delivering pulverized coal, and enable the coal feeder 16 on the B side to deliver pulverized coal according to the load requirement; S12: A portion of the air from the primary air main pipe 12 carries the pulverized coal from the coal mill 1 into the coarse powder separator 21 on the A side for separation; S13: The fine powder separated by the coarse powder separator 21 on the A side is transported to the cyclone separator 6, and after cyclone separation, it falls into the pulverized coal bin 5 for storage, and the exhaust gas of the cyclone separator 6 is sent to the high-level burner 20 for combustion; S14: Another portion of the air from the primary air main pipe 12 carries the pulverized coal from the coal mill 1 into the coarse powder separator 22 on the B side for separation. The separated fine powder is then transported to the burner 11 for combustion, completing the pulverization process. When the unit is under high load or in normal operation: S21: The coal feeder 4 on the A side and the coal feeder 16 on the B side are simultaneously fed with pulverized coal according to load requirements; S22: A portion of the air from the primary air main pipe 12 carries the pulverized coal from the coal mill 1 into the coarse powder separator 21 on the A side for separation; S23: The fine powder separated by the coarse powder separator 21 on the A side is transported to the burner 23 on the A side through the cyclone separator 6, the air lock discharger 8 and the air-powder mixer 24 to participate in combustion; S24: another part of the air from the primary air main pipe 12 carries the pulverized coal ground by the coal mill 1 into the coarse powder separator 22 on the B side for separation, and then the separated fine powder is transported to the burner 11 for combustion, thereby completing the pulverizing process.

[0044] The method stops the coal feeder 4 on the A side from delivering pulverized coal when the unit is running at low load, thereby switching the operation mode of the A side of the coal mill 1 to the pulverized coal storage mode, storing the pulverized coal separated on the A side of the coal mill 1 in the pulverized coal bin, and allowing the exhaust gas to participate in the combustion, while enabling the coal feeder 16 on the B side to deliver pulverized coal for combustion according to the load demand, thereby ensuring the stable operation of the coal mill 1 and avoiding the operation of the coal mill 1 from affecting the operation of the boiler, thereby improving the reliability of the system; when the unit is running at high load or in normal operation, the coal feeder 4 on the A side and the coal feeder 16 on the B side are simultaneously delivered for combustion according to the load demand, thereby realizing the system's bilateral parallel processing capability, improving the overall flexibility and efficiency of the pulverizing system, adjusting the working status of both sides according to actual needs, optimizing resource allocation, and ensuring the continuity and stability of the pulverizing process.

[0045] A boiler comprising the aforementioned pulverizing system coupled with an external pulverizing silo has good combustion stability, high combustion efficiency, and low operating costs, and is of great significance for solving the problem of large-scale new energy power grid integration and consumption.

[0046] In summary, the present invention provides a pulverizing system, a pulverizing method and a boiler coupled with an external powder silo. By dividing the two sides of a double-inlet and double-outlet coal mill into two operating modes, without reducing the output of the coal mill 1, one side of the coal mill 1 is operated in a direct-blowing mode to ensure the basic load, and the other side of the coal mill 1 is operated in a powder storage mode, a powder delivery mode and a powder storage and delivery mode according to the load requirements of the unit. The operating modes are flexible and changeable, which ensures the stability of different unit loads and improves the unit load change rate. At the same time, the coal mill 1 always operates at the most economical load, thereby improving the economy and load adaptability of the coal mill 1.

[0047] The above description is merely 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 replacements, and these modifications and replacements are also within the scope of protection covered by the claims.

Claims

1. A powder making system coupled with an external powder silo, characterized in that: The invention comprises a coal mill (1), wherein an A-side coarse powder separator (21) and an A-side coal feeder (4) are provided on one side of the coal mill (1), and a B-side coarse powder separator (22) and a B-side coal feeder (16) are provided on the other side of the coal mill (1); the A-side coarse powder separator (21) and the B-side coarse powder separator (22) are both connected to a primary air main pipe (12); The pulverized coal outlet of the A-side coarse powder separator (21) is sequentially connected to a cyclone separator (6), an air lock discharger (8), an air-powder mixer (24), and an A-side burner (23); the air-powder mixer (24) is connected to a primary air main pipe (12); the exhaust gas outlet of the cyclone separator (6) is divided into two paths, one of which is connected to a high-position burner (20), and the other is connected to the air-powder mixer (24); The coal powder outlet of the B-side coarse powder separator (22) is connected to a burner (11).

2. The powder making system coupled with an external powder silo according to claim 1, characterized in that: An A-side bypass damper (2) and an A-side capacity damper (3) are provided between the air supply end of the primary air main pipe (12) and the A-side coarse powder separator (21), and the A-side bypass damper (2) and the A-side capacity damper (3) are connected in parallel.

3. The powder making system coupled with an external powder silo according to claim 1, characterized in that: A B-side bypass damper (17) and a B-side capacity damper (18) are provided between the air supply end of the primary air main pipe (12) and the B-side coarse powder separator (22), and the B-side bypass damper (17) and the B-side capacity damper (18) are connected in parallel.

4. The powder making system coupled with an external powder silo according to claim 1, characterized in that: The coal powder outlet of the A-side coarse powder separator (21) is connected to the cyclone separator (6) via a coal powder collecting pipe (14).

5. The powder making system coupled with an external powder silo according to claim 1, characterized in that: The coal powder outlet of the A-side coarse powder separator (21) is provided with an A-side outlet valve (13).

6. The powder making system coupled with an external powder silo according to claim 1, characterized in that: The coal powder outlet of the B-side coarse powder separator (22) is provided with a B-side outlet valve (15).

7. The powder making system coupled with an external powder silo according to claim 1, characterized in that: The exhaust gas outlet of the cyclone separator (6) is provided with a powder exhaust fan (7).

8. The powder making system coupled with an external powder silo according to claim 1, characterized in that: An exhaust gas powder delivery valve (9) A is provided between the exhaust gas outlet of the cyclone separator (6) and the air-powder mixer (24); an exhaust gas powder delivery valve (19) B is provided between the exhaust gas outlet of the cyclone separator (6) and the high-position burner (20); and a powder delivery valve (10) is provided between the primary air main pipe (12) and the air-powder mixer (24).

9. A method for making flour using the flour making system coupled with an external flour silo according to any one of claims 1 to 8, characterized in that: include: When the unit is running at low load: The coal feeder (4) on the A side stops feeding coal powder, and the coal feeder (16) on the B side feeds coal powder according to load demand; A portion of the air from the primary air main pipe (12) carries the coal powder ground by the coal mill (1) into the coarse powder separator (21) on the A side for separation; The fine powder separated by the coarse powder separator (21) on the A side is transported to the cyclone separator (6), and after cyclone separation, falls into the coal powder bin (5) for storage, and the exhaust gas of the cyclone separator (6) is transported to the high-position burner (20) for combustion; Another part of the air from the primary air main pipe (12) carries the pulverized coal from the coal mill (1) into the coarse powder separator (22) on the B side for separation, and then the separated fine powder is transported to the burner (11) for combustion, thereby completing pulverizing; When the unit is under high load or in normal operation: The A-side coal feeder (4) and the B-side coal feeder (16) are configured to deliver coal powder at the same time according to the load requirements; A portion of the air from the primary air main pipe (12) carries the coal powder ground by the coal mill (1) into the coarse powder separator (21) on the A side for separation; The fine powder separated by the coarse powder separator (21) on the A side is transported to the burner (23) on the A side through the cyclone separator (6), the air lock discharger (8) and the air-powder mixer (24) to participate in combustion; Another part of the air from the primary air main pipe (12) carries the pulverized coal from the coal mill (1) into the coarse powder separator (22) on the B side for separation. The separated fine powder is then transported to the burner (11) for combustion, thereby completing pulverizing.

10. A boiler, characterized in that: A powder making system coupled with an external powder bin as described in any one of claims 1 to 8.

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