Direct-fired pulverizing unit, W-type flame-fired boiler system and its operation method

Abstract

This application relates to the field of boiler technology, providing a direct-fired pulverizing unit, a W-type flame combustion boiler system, and its operation method. The direct-fired pulverizing unit includes a grinding device, a separation module, and a mixing device. The separation module includes a cyclone dynamic separation device, an air-powder separation device, a first powder channel, a collector, and a second powder channel. By connecting the air-powder separation device to the first powder channel and the collector, a portion of the powdered material to be burned directly through the first powder channel, while the remaining powdered material enters the collector. The amount of powdered material fed from the collector into the second powder channel can be controlled according to the combustion load of the boiler system. After being mixed in the mixing device, the powdered material in the first and second powder channels is transported to the burner of the boiler system, improving the operational flexibility of the boiler system.

Description

Technical Field

[0001] This application relates to the field of boiler technology, specifically to a direct-fired pulverizing unit, a W-type flame combustion boiler system, and its operation method. Background Technology

[0002] Thermal power generation refers to a method of generating electricity by using the heat energy generated when combustibles burn and converting it into electrical energy through power generation devices. In my country, coal-fired boiler power generation is an important method of power generation for the power grid.

[0003] In the field of coal-fired boiler technology, a pulverizing unit is typically used to first crush and screen coal to obtain pulverized coal, which is then fed into the boiler for combustion. In existing direct-fired pulverizing units, the grinding device and the burner are directly connected. When the combustion load changes significantly, the only solution is to start and stop the grinding device. However, starting and stopping the grinding device takes time, and pulverization is also delayed. This limits the ability to quickly adapt to changes in unit load and fails to meet the requirements for flexible operation. Summary of the Invention

[0004] In view of this, embodiments of this application provide a pulverizing system, a W-type flame combustion boiler system, and an operating method to improve the flexibility of boiler operation.

[0005] In a first aspect, embodiments of this application provide a direct-blown pulverizing unit comprising: a grinding device for crushing unburned material to obtain crushed material, wherein the crushed material is mixed with a first airflow in the grinding device to obtain a first gas-solid mixture; a separation module comprising a cyclone dynamic separation device, an air-powder separation device, a first powder channel, a collector, and a second powder channel; wherein the cyclone dynamic separation device is connected to the grinding device for receiving and separating the first gas-solid mixture to obtain a second gas-solid mixture, the second gas-solid mixture comprising powdered unburned material of a preset particle size; the air-powder separation device is connected to the cyclone dynamic separation device for receiving and separating the second gas-solid mixture to obtain powdered unburned material; the outlet end of the air-powder separation device is connected to the collector and the first powder channel respectively, and the outlet end of the collector is connected to the second powder channel; the first powder channel and the second powder channel are used to convey powdered unburned material, and the collector can adjust the conveying amount of powdered unburned material in the second powder channel; and a mixing device, connected to the first powder channel and the second powder channel, for mixing the powdered unburned material in the first powder channel and the second powder channel and outputting unburned material.

[0006] According to an embodiment of the first aspect of this application, the air-powder separation device includes a first air-powder separator and a second air-powder separator connected in series; the first air-powder separator is connected between the cyclone dynamic separation device and the first powder channel, and is used to receive a second gas-solid mixture to achieve a first gas-solid separation to obtain a first powder and a third gas-solid mixture; the second air-powder separator is connected between the first air-powder separator and the collector, and is used to receive a third air-powder mixture and achieve a second gas-solid separation to obtain a second powder and exhaust gas.

[0007] According to an embodiment of the first aspect of this application, the mass of the first powder separated by the first air-powder separator accounts for 50% to 90% of the mass of the powdered material to be combusted.

[0008] According to an embodiment of the first aspect of this application, the mixing device includes a mixing channel and a plurality of conveying channels that are connected in communication with the mixing channel. The extending direction of the mixing channel intersects the extending direction of the conveying channels. The mixing channel is connected in communication with a first powder channel and a second powder channel for mixing powdered materials to be combusted. The plurality of conveying channels are used to distribute the powdered materials to a plurality of ignition points.

[0009] According to an embodiment of the first aspect of this application, a pressurizing device is also included, which is connected to the air-powder separation device for receiving exhaust gas and pressurizing the exhaust gas to obtain pressurized exhaust gas.

[0010] According to an embodiment of the first aspect of this application, the cyclone dynamic separation device includes a separation channel, the two ends of which are connected to a grinding device and an air-powder separation device respectively along their extension direction. The separation channel includes at least a first separation section and a second separation section distributed along the conveying direction of the crushed material. The first separation section is provided with a cyclone component to make the first gas-solid mixture rotate to achieve primary separation and obtain intermediate material. The second separation section is provided with a rotating component, which rotates to make the intermediate material undergo centrifugal motion to achieve secondary separation.

[0011] Secondly, embodiments of this application provide a W-type flame combustion boiler system, including a steady-state combustion unit, a dust-removing flue gas unit, and at least one set of direct-fired pulverizing units according to any one of claims 1-6. The pulverizing unit is connected to the steady-state combustion unit to provide powdered combustible material to the combustion system. The steady-state combustion unit includes a boiler body and a vertical concentration-lean separation device disposed on the boiler body. The vertical concentration-lean separation device includes a concentration side outlet and a lean side outlet. The vertical concentration-lean separation device is used to move more than 70% of the powdered combustible material to the concentration side outlet for combustion under gravity during operation, while the remaining powdered combustible material is burned at the lean side outlet. The steady-state combustion unit is used to burn the powdered combustible material to obtain heat and generate flue gas. The dust-removing flue gas unit is connected to the steady-state combustion unit and is used to remove dust from the flue gas generated by the steady-state combustion unit and discharge it.

[0012] According to an embodiment of the second aspect of this application, the vertical concentration-dispersion device includes a vertical separation tube and a powder inlet, a dispersion outlet, and a concentration outlet connected in communication with the vertical separation tube. The dispersion outlet is located at the top of the vertical separation tube, and the concentration outlet is located at the bottom of the vertical separation tube. The powder inlet is located on the side wall of the vertical separation tube and is used to introduce a gas-solid mixture with a preset velocity. The vertical concentration-dispersion device also includes a first control valve located at the dispersion outlet for adjusting the pressure at the dispersion outlet, and a second control valve located at the concentration outlet for adjusting the pressure at the concentration outlet.

[0013] According to an embodiment of the second aspect of this application, the boiler body includes a wall portion and a furnace chamber enclosed by the wall portion. The wall portion includes an upper arch portion and a lower arch portion connected to each other. The upper arch portion includes an upper rich side nozzle and an upper secondary air nozzle, and the upper rich side nozzle is connected to the rich side outlet. The lower arch portion includes a lower light side nozzle and a lower secondary air nozzle, and the lower light side nozzle is connected to the light side outlet. The lower secondary air nozzle is configured to be inclined toward the ground when in operation.

[0014] According to an embodiment of the second aspect of this application, the under-arch light-side nozzle is configured to tilt towards the ground in the working state, and the under-arch light-side nozzle is divided into multiple light-side nozzle sections by a baffle, so that the powdery combustible material enters the furnace layer by layer downward.

[0015] According to an embodiment of the second aspect of this application, it further includes a plurality of spaced-apart flame-retardant belts distributed on the inner wall of the furnace.

[0016] According to an embodiment of the second aspect of this application, the dust removal flue gas unit includes an economizer, a medium-temperature dust removal device, a denitrification device, and a nano-purifier connected in sequence; the economizer is connected to the boiler body and is used to recover the waste heat of the flue gas, the medium-temperature dust removal device is used to remove dust from the flue gas, the denitrification device is used to remove nitrogen oxides from the flue gas, and the nano-purifier is used for secondary dust removal of the flue gas.

[0017] Thirdly, this application provides an operation method for a W-type flame combustion boiler system based on the above, including: feeding coal into a direct-fired pulverizing unit to obtain powdered material to be burned; allowing the powdered material to enter a vertical concentration-lean separation device, adjusting the pressure P1 at the concentration side outlet and the pressure P2 at the lean side outlet to satisfy the relationship: P1 = 10%P2 ~ 30%P2; adjusting the secondary air ratio of the secondary air nozzles above and below the arch to (50 ~ 60): (40 ~ 50).

[0018] Compared with the prior art, the embodiments of this application have at least the following beneficial effects:

[0019] The direct-fired pulverizing unit of this application embodiment includes a grinding device, a separation module, and a mixing device. The grinding device can crush the material to be burned to obtain crushed material and output a first gas-solid mixture. The separation module can process the first gas-solid mixture to obtain powdered material to be burned. Specifically, the separation module includes a cyclone dynamic separation device, an air-powder separation device, a first powder channel, a collector, and a second powder channel. The cyclone dynamic separation device can separate the first gas-solid mixture to obtain a second gas-solid mixture including powdered material to be burned with a preset particle size. The air-powder separation device can separate the second gas-solid mixture to obtain powdered material to be burned. By connecting the air-powder separation device with the first powder channel and the collector respectively... The device is connected to the combustion chamber, allowing a portion of the powdered material to be burned directly through the first powder channel, while the other portion enters the collector. The amount of powdered material fed into the second powder channel by the collector can be controlled according to the combustion load of the boiler system. After the powdered material in the first and second powder channels is mixed in the mixing device, it is transported to the burner of the boiler system. When the combustion load changes, the direct-fired pulverizing unit of this application can respond by adjusting the amount of powdered material fed into the second powder channel by the collector, instead of responding by starting and stopping the grinding device, thus avoiding the time delay of starting and stopping the grinding device and improving the operational flexibility of the boiler system. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0021] Figure 1 This is a schematic diagram showing the connection relationship between the direct-fired pulverizing unit, the steady-state combustion unit, and the dust-removing flue gas unit provided in the embodiments of this application.

[0022] Figure 2 This is a schematic diagram showing the connection relationship between the direct-fired pulverizing unit, the steady-state combustion unit, and the dust-removing flue gas unit, provided in another embodiment of this application.

[0023] Figure 3 This is a schematic diagram of the structure of the cyclone dynamic separation device provided in the embodiments of this application.

[0024] Figure 4 This is a schematic diagram of the steady-state combustion unit provided in an embodiment of this application.

[0025] Figure 5 A burner distribution diagram in a W-type flame combustion boiler system provided in an embodiment of this application.

[0026] Figure label:

[0027] 1. Direct-fired pulverizing unit; 3. Steady-state combustion unit; 5. Dust-removing flue gas unit;

[0028] 10. Grinding device; 11. Separation module; 12. Cyclone dynamic separation device; 121. Separation channel; 122. First separation section; 123. Cyclone assembly; 124. Second separation section; 125. Rotating component; 13. Air-powder separation device; 13a. First air-powder separator; 13b. Second air-powder separator; 14. First powder channel; 15. Collector; 16. Second powder channel; 17. Mixing device; 18. Pressurizing device; 19. Exhaust gas reheating device; 31. Boiler body; 32. Vertical thick-lean separation device; 32a. Lean side outlet; 32b. Thick side outlet; 32c. Powder inlet; 32d. Vertical separation pipe; 33. Wall; 34. Upper part of the arch; 34a. Thick side nozzle on the upper part of the arch; 35. Lower part of the arch; 35a. Lean side nozzle on the lower part of the arch; 35b. Secondary air nozzle on the lower part of the arch; 36. Furnace.

[0029] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0030] To make the purpose, technical solution, and beneficial technical effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the embodiments described in this specification are merely for explaining this application and are not intended to limit it.

[0031] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, although not explicitly stated, every point or individual value between the endpoints of the range is included within that range. Therefore, each point or individual value can be used as its own lower or upper limit and combined with any other point or individual value or with other lower or upper limits to form a range not explicitly stated.

[0032] In the description of this application, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, and "multiple" in "one or more" means two or more.

[0033] In the field of coal-fired boiler technology, a pulverizing unit is typically used to first crush and screen coal to obtain pulverized coal, which is then fed into the boiler for combustion. In existing direct-fired pulverizing units, the grinding device and the burner are directly connected. When the combustion load changes significantly, the only solution is to start and stop the grinding device. However, starting and stopping the grinding device takes time, and pulverization is also delayed. This limits the ability to quickly adapt to changes in unit load and fails to meet the requirements for flexible operation.

[0034] To address the problems of existing technologies, this application provides a direct-fired pulverizing unit, a W-type flame combustion boiler system, and an operating method, thereby improving the operational flexibility of the boiler system. The direct-fired pulverizing unit provided in this application embodiment is described below.

[0035] Figure 1 This is a schematic diagram showing the connection relationship of a direct-blown pulverizing unit 1 provided in some embodiments of this application.

[0036] like Figure 1 As shown, this application provides a direct-blown pulverizing unit 1, including: a grinding device 10 for crushing the material to be burned to obtain crushed material, wherein the crushed material is mixed with a first airflow in the grinding device 10 to obtain a first gas-solid mixture; a separation module 11, including a cyclone dynamic separation device 12, an air-powder separation device 13, a first powder channel 14, a collector 15, and a second powder channel 16; wherein the cyclone dynamic separation device 12 is connected to the grinding device 10 and is used to receive and separate the first gas-solid mixture to obtain a second gas-solid mixture, wherein the second gas-solid mixture includes powdered material to be burned with a preset particle size; the air-powder separation device 13 and the... A cyclone dynamic separator 12 is connected to receive and separate a second gas-solid mixture to obtain powdered combustible material; the outlet end of the air-powder separator 13 is connected to the collector 15 and the first powder channel 14 respectively, and the outlet end of the collector 15 is connected to the second powder channel 16; the first powder channel 14 and the second powder channel 16 are used to convey powdered combustible material, and the collector 15 can adjust the conveying amount of powdered combustible material in the second powder channel 16; a mixing device 17 is connected to the first powder channel 14 and the second powder channel 16 to mix the powdered combustible material in the first powder channel 14 and the second powder channel 16 and output combustible material.

[0037] In this embodiment of the application, the direct-fired pulverizing unit 1 is used to provide powdered materials to be burned into the boiler system. The powdered materials to be burned can be pulverized coal.

[0038] For example, the material to be burned first enters the grinding device 10 and is crushed in the grinding device 10 to obtain crushed material. The material to be burned can enter the grinding device 10 by being fed in by a coal feeder. The grinding device 10 can be connected to a primary air duct, which contains air introduced by an induced draft fan, or the grinding device 10 can be connected to an exhaust gas duct, which contains exhaust gas, or the grinding device 10 can be connected to both the primary air duct and the exhaust gas duct simultaneously. In this embodiment, the first airflow can be air introduced by an induced draft fan in the primary air duct, exhaust gas in the exhaust gas duct, or a mixture of air and exhaust gas. Exhaust gas refers to an airflow that contains no or a small amount of coal powder. Preferably, the exhaust gas in the exhaust gas duct is pressurized exhaust gas. The first airflow is mixed with the crushed material in the grinding device 10 to obtain a first gas-solid mixture.

[0039] After the first gas-solid mixture enters the separation module 11, it first enters the cyclone dynamic separator 12. The cyclone dynamic separator 12 separates the larger particles of the first gas-solid mixture. The larger particles can be returned to the grinding device 10 for further crushing. The remaining components in the first gas-solid mixture constitute the second gas-solid mixture, which then enters the air-powder separator 13 for further separation. The second gas-solid mixture includes powdered unburned material of a preset particle size. The preset particle size can be set according to the combustion requirements of the boiler system. This application does not specifically limit the value of the preset particle size. The particle size of the powdered unburned material in the second gas-solid mixture can be specifically screened by the cyclone dynamic separator 12.

[0040] The second gas-solid mixture enters the air-powder separator 13. The function of the air-powder separator 13 is to achieve gas-solid separation of the second gas-solid mixture, separating it into powdered unburned material and exhaust gas. The air-powder separator 13 only needs to meet the gas-solid separation effect. For example, a multi-tube dust collector or fine powder separator commonly used in the prior art can be used.

[0041] The outlet of the air-powder separator 13 is connected to the collector 15 and the first powder channel 14, respectively. The outlet of the collector 15 is connected to the second powder channel 16. This arrangement can divide the powdery material to be burned into two parts. One part of the powdery material to be burned goes directly through the first powder channel 14 for combustion, while the other part enters the collector 15. In this application, the amount of powdery material to be burned from the collector 15 to the second powder channel 16 can be controlled according to the combustion load of the boiler system. For example, the capacity of the collector 15 can be the amount of powdery material to be burned that is required for the boiler system to burn at full load for 5 to 15 minutes, without occupying a large space. After the powdery material to be burned in the first powder channel 14 and the second powder channel 16 is mixed in the mixing device 17, it is transported to the burner of the boiler system. When the combustion load changes, the direct-fired pulverizing unit 1 of this application can respond by adjusting the amount of powdery material to be burned from the collector 15 to the second powder channel 16, instead of responding by starting and stopping the grinding device 10.

[0042] In summary, the direct-fired pulverizing unit 1 of this application embodiment includes a grinding device 10, a separation module 11, and a mixing device 17. The grinding device 10 can crush the material to be burned to obtain crushed material and output a first gas-solid mixture. The separation module 11 can process the first gas-solid mixture to obtain powdered material to be burned. Specifically, the separation module 11 includes a cyclone dynamic separation device 12, an air-powder separation device 13, a first powder channel 14, a collector 15, and a second powder channel 16. The cyclone dynamic separation device 12 can separate the first gas-solid mixture to obtain a second gas-solid mixture including powdered material to be burned with a preset particle size. The air-powder separation device 13 can separate the second gas-solid mixture to obtain powdered material to be burned. By connecting the air-powder separation device 13 with the first powder channel... 14. The collector 15 is connected so that a portion of the powdery material to be burned goes directly through the first powder channel 14 for combustion, while the other portion enters the collector 15. The amount of powdery material to be burned from the collector 15 to the second powder channel 16 can be controlled according to the combustion load of the boiler system. The powdery material to be burned in the first powder channel 14 and the second powder channel 16 is mixed in the mixing device 17 and then transported to the burner of the boiler system. When the combustion load changes, the direct-fired pulverizing unit 1 of this application can respond by adjusting the amount of powdery material to be burned from the collector 15 to the second powder channel 16, instead of responding by starting and stopping the grinding device 10, thus avoiding the time delay of starting and stopping the grinding device 10 and improving the flexibility of boiler system operation.

[0043] In some embodiments, please refer to Figure 2The air-powder separation device 13 includes a first air-powder separator 13a and a second air-powder separator 13b connected in series. The first air-powder separator 13a is connected between the cyclone dynamic separation device 12 and the first powder channel 14, and is used to receive the second gas-solid mixture to achieve the first gas-solid separation to obtain the first powder and the third gas-solid mixture. The second air-powder separator 13b is connected between the first air-powder separator 13a and the collector 15, and is used to receive the third air-powder mixture and achieve the second gas-solid separation to obtain the second powder and the exhaust gas.

[0044] The second gas-solid mixture undergoes a first gas-solid separation in the first air-coal separator 13a, yielding a first powder and a third gas-solid mixture. The first powder enters the first powder channel 14. The third gas-solid mixture undergoes a second gas-solid separation in the second air-coal separator 13b, yielding a second powder and exhaust gas. The second powder enters the collector 15. Exhaust gas refers to an airflow containing little or no coal powder. The exhaust gas can be introduced into the combustion unit of the boiler system as tertiary air, or into the grinding mill 10 as primary airflow. It can be understood that the total mass of the first powder separated by the first air-coal separator 13a and the second powder separated by the second air-coal separator 13b is approximately equal to the total mass of the powdered material to be burned.

[0045] On the one hand, this application establishes independent first air-powder separators 13a and 13b, with the first air-powder separator 13a connected to the first powder channel 14, and the second air-powder separator 13b connected to the collector 15 and the second powder channel 16. This allows for different separation efficiencies in the first air-powder separator 13a and the second air-powder separator 13b, resulting in different distribution amounts of the powdery material to be combusted entering the first powder channel 14 and the collector 15, making the process easier to control. On the other hand, the combined use of the first air-powder separator 13a and the second air-powder separator 13b can reduce the space occupied by a single air-powder separation device 13, facilitating efficient space utilization. For example, the first air-powder separator 13a can be a multi-tube dust collector, and the second air-powder separator 13b can be a fine powder separator. Multi-tube dust collectors offer better gas-solid separation, and a multi-tube dust collector with a dust removal efficiency of 50%-90% can be selected as needed.

[0046] In some embodiments, the mass of the first powder separated by the first air-powder separator 13a accounts for 50% to 90% of the mass of the powdered material to be combusted.

[0047] The first powder accounts for approximately 50%-90% of the total amount of powdered materials to be burned, and can be used for direct combustion in the boiler system. Preferably, the first powder accounts for approximately 60%-80% of the total amount of powdered materials to be burned, which can ensure that a large amount of powdered materials to be burned directly. The remaining powdered materials to be burned can be temporarily stored or burned directly depending on the combustion load, thus improving the flexibility of boiler operation.

[0048] In some embodiments, the mixing device 17 includes a mixing channel and a plurality of conveying channels that are connected through the mixing channel. The extending direction of the mixing channel intersects the extending direction of the conveying channels. The mixing channel is connected through the first powder channel 14 and the second powder channel 16 for mixing powdered materials to be combusted. The conveying channels are used to distribute the powdered materials to a plurality of ignition points.

[0049] One end of the mixing channel extends through and connects to multiple conveying channels, while the other end connects to the first powder channel 14 and the second powder channel 16. This allows the powdered materials to be combusted in the first powder channel 14 and the second powder channel 16 to be mixed within the mixing channel, which helps improve combustion stability. After being mixed in the mixing channel, the powdered materials are distributed to multiple ignition points via the conveying channels. These ignition points can be burners; for example, the mixing device 17 can be a pulverized coal distributor.

[0050] By setting up the mixing device 17, the burners and the grinding device 10 are no longer in one-to-one correspondence. The burners have the conditions for uniform operation and shutdown at intervals, and the burner operation interval will not be uneven due to the shutdown of the coal mill. The burners can be used at uniform intervals, and the heat load in the width direction of the furnace is evenly distributed, ensuring that the thermal stress of the boiler furnace heating surface is balanced under each load, and ensuring the safe operation of the furnace.

[0051] In some embodiments, a pressurizing device 18 is also included, which is connected to the air-powder separator 13 and is used to receive exhaust gas and pressurize the exhaust gas to obtain pressurized exhaust gas.

[0052] This application obtains pressurized exhaust gas by pressurizing the exhaust gas. The pressurized exhaust gas can be introduced into the grinding device 10 to replace part of the primary air, reduce the primary air rate, and increase the secondary air rate. The secondary air can better organize combustion, improve the combustion effect of powdered materials to be burned, and achieve energy saving effect.

[0053] In some embodiments, the system further includes a waste gas reheating device 19, which is connected to a pressurizing device 18 and is used to receive and heat the waste gas. The heated waste gas can reduce the decrease in furnace temperature and improve combustion stability.

[0054] In some embodiments, please refer to Figure 3The cyclone dynamic separation device 12 includes a separation channel 121. The two ends of the separation channel 121 along its own extension direction are respectively connected to the grinding device 10 and the air-powder separation device 13. The separation channel 121 includes at least a first separation section 122 and a second separation section 124 distributed along the crushed material conveying direction. The first separation section 122 is provided with a cyclone component 123 to make the first gas-solid mixture rotate to achieve primary separation and obtain intermediate material. The second separation section 124 is provided with a rotating component 125. The rotating component 125 rotates to make the intermediate material undergo centrifugal motion to achieve secondary separation.

[0055] The function of the cyclone dynamic separator 12 is to separate crushed materials to obtain powdered materials of qualified fineness for combustion. Specifically, the cyclone dynamic separator 12 includes a first separation channel 121, which includes at least a first separation section 122 and a second separation section 124 distributed along the direction of conveying the crushed materials. The direction of conveying the crushed materials refers to the flow direction of the crushed materials from the inlet to the outlet of the cyclone dynamic separator 12. After entering the cyclone dynamic separator 12, the crushed materials first undergo a first separation in the first separation section 122, and then undergo a second separation in the second separation section 124.

[0056] The first separation section 122 is equipped with a cyclone assembly 123, which can cause the airflow of crushed material entering the cyclone dynamic separation device 12 to rotate. The larger particles in the crushed material are subjected to greater centrifugal force, and the larger particles will slide down along the first channel and be separated. A return powder pipe can be set so that the larger particles can be output from the return powder pipe. The smaller particles in the crushed material continue to enter the second separation section 124 as the initial material.

[0057] The swirl assembly 123 can be a swirl guide vane, and the angle between the swirl guide vane and the axis of the separation channel 121 can be adjusted. It is understood that the greater the swirl velocity or the larger the cutting angle, the smaller the coal powder particles that can be separated, and the finer the initial material. Conversely, the smaller the swirl velocity or the smaller the cutting angle, the larger the coal powder particles that can be separated, and the finer the initial material. Thus, by adjusting the angle between the swirl guide vane and the axis of the first separation channel 121, the swirl velocity and cutting angle of the air-coal mixture in the first separation zone can be adjusted, and different swirl velocities and cutting angles can affect the fineness of the separated coal powder.

[0058] The second separation section 124 is equipped with a rotating component 125, which can be a moving impeller. Taking the moving impeller as an example, the rotation of the moving impeller itself will form a rotating separation zone. The initial material in the rotating separation zone will be subjected to the centrifugal force applied by the moving impeller, and the coal powder particles themselves will be subjected to the traction force of the airflow. When the centrifugal force on the coal powder particles is greater than the traction force, the coal powder particles will be separated to the outside of the moving impeller; when the centrifugal force on the coal powder particles is less than the traction force, the coal powder particles will be separated to the inside of the moving impeller, obtaining powdered material to be burned. It can be understood that the larger the particles of the initial material, the greater the centrifugal force applied by the moving impeller in the rotating separation zone. Therefore, the coal powder with larger particles and unqualified fineness in the initial material will be passively separated by the impeller to the outside of the first blade. The coal powder with unqualified fineness will be separated from the cyclone dynamic separation device 12 under the action of gravity and recycled to the grinding device 10 for re-grinding. The initial material, consisting of smaller, qualified coal powder particles, is passively separated by the impeller and discharged through the powder outlet pipe to the air-coal separation unit 13. Please refer to... Figure 3 Solid arrows indicate the direction of movement of smaller coal powder particles, while dashed arrows indicate the direction of movement of larger coal powder particles.

[0059] Secondly, please refer to Figure 1 , Figure 2 and Figure 4 This application provides a W-type flame combustion boiler system, including a steady-state combustion unit 3, a dust removal flue gas unit 5, and at least one set of direct-fired pulverizing units 1 as described in any one of the claims. The pulverizing unit is connected to the steady-state combustion unit 3 to provide powdered material to the combustion system. The steady-state combustion unit 3 is used to burn the powdered material to obtain heat and generate flue gas. The vertical concentration-lean separation device 32 includes a concentration side outlet 32b and a lean side outlet 32a. The vertical concentration-lean separation device 32 is used to move more than 70% of the powdered material to the concentration side outlet 32b for combustion under gravity during operation, while the remaining powdered material is burned at the lean side outlet 32a. The dust removal flue gas unit 5 is connected to the steady-state combustion unit 3 and is used to remove dust from the flue gas generated by the steady-state combustion unit 3 and discharge it.

[0060] The W-type flame-fired boiler system provided in this application embodiment may include a set of direct-fired pulverizing units 1. A mixing device 17 in the direct-fired pulverizing unit 1 is connected to a steady-state combustion unit 3, specifically, to the burner in the steady-state combustion unit 3. The mixing device 17 distributes powdered pulverized material to the burner. Because the mixing device 17 uniformly distributes the powdered pulverized material to the burner, the burner has the condition of uniformly starting and stopping at intervals, preventing uneven burner operation intervals due to the shutdown of the coal mill. The burners can be used at uniform intervals, resulting in a uniform heat load distribution along the width of the furnace, ensuring balanced thermal stress on the boiler furnace heating surface under various loads and guaranteeing safe furnace operation. The W-type flame-fired boiler system provided in this application embodiment may include two sets of direct-fired pulverizing units 1. Taking 36 burners as an example, please refer to [link to relevant documentation]. Figure 5 A direct-fired pulverizing unit 1 is installed on both the front and rear walls of the furnace. The burners in the W-type flame-fired boiler system are divided into two groups (the first group includes burners 1-18, and the second group includes burners 19-36). The two sets of direct-fired pulverizing units 1 are connected to the two groups of burners respectively. One set of direct-fired pulverizing units supplies powdered pulverized material to the first group of burners, and the other set supplies powdered pulverized material to the second group of burners. This allows for the unified distribution of powdered pulverized material to the two groups of burners by the two mixing devices 17, improving the flexibility of pulverized material supply. The W-type flame-fired boiler system provided in this application embodiment may also include three, four, five, or six sets of direct-fired pulverizing units 1, which will not be elaborated further in this application.

[0061] In this embodiment, the steady-state combustion unit 3 includes a vertical concentration-lean separation device 32, which concentrates the powdered material with a mass fraction of 70% or more at the concentration side outlet 32b for combustion, thereby increasing the amount of powder at the concentration side outlet 32b and reducing the amount of powder ejected from the lean side outlet 32a. This makes it easier for the powder to ignite near the concentration side nozzle 34a in the furnace, increasing the pulverized coal burnout rate. Furthermore, the heat released by the pulverized coal combustion increases, enhancing the combustion temperature maintenance effect and thus improving stability under low load conditions.

[0062] In some embodiments, please continue reading Figure 4The vertical concentration-degradation separation device 32 includes a vertical separation pipe 32d and a degradation side 32a, a concentrated side outlet 32b, and a powder inlet 32c connected to the vertical separation pipe 32d. The degradation side is located at the top of the vertical separation pipe 32d, the concentrated side outlet 32b is located at the bottom of the vertical separation pipe 32d, and the powder inlet 32c is located on the side wall of the vertical separation pipe 32d. The powder inlet 32c is used to introduce a gas-solid mixture with a preset velocity. The vertical concentration-degradation separation device 32 also includes a first control valve located at the degradation side 32a for adjusting the pressure at the degradation side 32a, and a second control valve located at the concentrated side 32b for adjusting the pressure at the concentrated side outlet 32b. After the gas-solid mixture with a preset velocity enters the vertical separation pipe 32d through the powder inlet 32c, it rotates on the inner wall of the vertical separation pipe 32d. The coal powder in the gas-solid mixture generates centrifugal force and rotates against the inner wall. Under the combined action of gravity and centrifugal force, the coal powder moves downward. In this embodiment, the vertical rich-lean separation device 32 is arranged in the steady-state combustion unit 3 such that the vertical rich-lean separation device 32 is at a 60° angle to the ground. ° ~90 ° Angles of any degree between them; for example, the vertical concentration separation device 32 can be at a 60° angle to the ground. ° 70 ° 80 ° 90 ° Please refer to... Figure 4 The vertical concentration separation device 32 is installed vertically on the ground.

[0063] As an example, Figure 4 Only the structure of the upper part 34 and the lower part 35 of the arch on one side of the boiler body 31 is shown. It can be understood that a vertical thick and thin separation device 32 is also provided on the other side of the boiler body 31. Preferably, the vertical thick and thin separation devices 32 on both sides are symmetrically distributed.

[0064] In this embodiment, by coordinating the first and second control valves, most of the powdered combustible material can move towards the concentrated side 32b at the bottom under the combined action of pressure difference and gravity, while only a small portion of the powdered combustible material is carried by air to the light side 32a at the top. This results in a significantly higher coal powder concentration in the gas-solid mixture at the concentrated side outlet 32b compared to the light side outlet 32a, thus improving the concentration-light separation effect of the gas-solid mixture. For example, the pressure P1 at the concentrated side outlet 32b and the pressure P2 at the light side outlet 32a satisfy the following relationship: P1 = 10%P2 ~ 30%P2.

[0065] In some embodiments, the boiler body 31 includes a wall portion 33 and a furnace 36 formed by the wall portion 33. The wall portion 33 includes an upper arch portion 34 and a lower arch portion connected to each other. The upper arch portion 34 includes an upper arch rich side nozzle 34a and an upper arch secondary air nozzle. The upper arch rich side nozzle 34a is connected to the rich side outlet 32b. The lower arch portion includes a lower arch light side nozzle 35a and a lower arch secondary air nozzle 35b. The lower arch light side nozzle 35a is connected to the light side outlet 32a. The lower arch secondary air nozzle 35b is configured to be inclined toward the ground when in operation.

[0066] In this embodiment, the powdered material to be burned at the light-side outlet 32a enters the furnace 36 from the lower part of the arch, which can reduce the ignition heat of the rich-side 32b and improve the combustion stability of the rich-side 32b. The secondary air nozzle 35b under the arch is set to be inclined towards the ground in the working state, which can improve the penetration of the secondary air under the arch, facilitate the downward extension of the flame, increase the combustion stroke of pulverized coal, increase the burnout rate, and reduce the carbon content of fly ash.

[0067] In some embodiments, the under-arch light side nozzle 35a is configured to tilt towards the ground in the working state, and the under-arch light side nozzle 35a is divided into multiple light side nozzle sections by a partition, so that the powdered material to be burned enters the furnace 36 in layers downward.

[0068] The stratified powdered material is introduced in layers, which can reduce the ignition heat of the concentrated side outlet 32b and improve the combustion stability of the concentrated side outlet 32b. For example, there can be two, three, four or more layers.

[0069] In some embodiments, the furnace may also include a plurality of spaced-apart flame-retardant belts distributed on the inner wall of the furnace chamber 36.

[0070] This application uses spaced-out flame-retardant belts instead of sheet-type flame-retardant belts, which can maintain the temperature balance of each section of the furnace 36 on the one hand, and prevent destructive coking in the furnace 36 on the other hand.

[0071] In some embodiments, the dust removal flue gas unit 5 includes an economizer, a medium-temperature dust removal device, a denitrification device, and a nano-purifier connected in sequence.

[0072] In this application, the economizer is connected to the boiler body 31, specifically to the lower part of the flue of the boiler body 31, and is used to recover the waste heat of the flue gas. It is a heating surface that heats the boiler body feedwater to saturated water under the pressure of the steam drum. The economizer can absorb the heat of the high-temperature flue gas, reduce the exhaust temperature of the flue gas, save energy, and improve efficiency.

[0073] This application adds a medium-temperature dust removal device to the dust removal flue gas unit 5. This device removes 60%-95% or more of the fly ash particles at 400℃-600℃. Preferably, it utilizes cyclone separation for dust removal. The denitrification device is an SCR denitrification device. Excessive fly ash can negatively impact the SCR denitrification device, leading to excessive ammonia escape. Excessive ammonia escape further accelerates the damage to heat storage elements such as the air preheater and low-temperature economizer, causing blockages, wear, and corrosion. The medium-temperature dust removal device, located between the economizer and the denitrification system, reduces flue gas fineness resistance, lowers the power consumption of the boiler primary air fan, forced draft fan, and induced draft fan, reduces wear on the denitrification catalyst and air preheater heat exchange elements, and lowers unit maintenance costs. The denitrification device is used to remove nitrogen oxides from the flue gas, and the nano-purifier is used for secondary dust removal of the flue gas. The nano-purifier of this application uses the temperature and pressure of the flue gas itself for centrifugal separation and flow separation without consuming external energy. It can remove dust, SO3 aerosol, gypsum droplets and sulfuric acid rain with low investment and low maintenance costs, so that the flue gas can meet the ultra-clean emission requirements.

[0074] Thirdly, this application provides an operation method for the above-mentioned W-type flame combustion boiler system, comprising:

[0075] Coal is fed into the direct-fired pulverizing unit 1 to obtain powdered material ready for combustion.

[0076] The powdered material to be combusted is introduced into the vertical concentration-lean separation device 32. The pressure P1 at the concentration side outlet 32b and the pressure P2 at the lean side outlet 32a are adjusted to satisfy the following relationship: P1 = 10%P2 ~ 30%P2.

[0077] Adjust the secondary air ratio of the secondary air nozzles 35b above and below the arch to 50-60:40-50.

[0078] This application improves combustion stability under low load by adjusting the pressure at the concentrated side outlet 32b and the diluted side outlet 32a of the vertical concentrated-dilute separation device 32, allowing over 70%, or even 85%, of the powdery unburned material to concentrate at the concentrated side outlet 32b for combustion. Simultaneously, by adjusting the secondary air ratio at the upper and lower secondary air nozzles 35b of the arch, better staged combustion can be achieved, reducing NO₂ levels. x Production volume.

[0079] The foregoing description of this application is not intended to describe every disclosed implementation or method. Instead, the following description provides more specific examples of exemplary embodiments. Throughout the application, guidance is provided through a series of embodiments that can be used in various combinations. The examples listed are representative only and should not be construed as exhaustive.

[0080] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A direct-blown pulverizing unit, characterized in that, include: A grinding device is used to crush materials to be burned to obtain crushed materials, wherein the crushed materials are mixed with a first gas flow in the grinding device to obtain a first gas-solid mixture. The separation module includes a cyclone dynamic separation device, an air-powder separation device, a first powder channel, a collector, and a second powder channel; The cyclone dynamic separation device is connected to the grinding device and is used to receive and separate the first gas-solid mixture to obtain a second gas-solid mixture, wherein the second gas-solid mixture includes powdered material to be combusted with a preset particle size. The air-powder separator is connected to the cyclone dynamic separator and is used to receive and separate the second gas-solid mixture to obtain the powdered material to be combusted. The outlet end of the air-powder separator is connected to the collector and the first powder channel, respectively, and the outlet end of the collector is connected to the second powder channel. The first powder channel and the second powder channel are used to transport the powdered material to be combusted, and the collector can adjust the amount of powdered material to be combusted in the second powder channel. A mixing device, connected in communication with the first powder channel and the second powder channel, is used to mix the powdered flammable material in the first powder channel and the second powder channel and output the flammable material.

2. The direct-blown pulverizing unit according to claim 1, characterized in that, The air-dust separation device includes a first air-dust separator and a second air-dust separator connected in series. The first air-powder separator is connected between the cyclone dynamic separation device and the first powder channel, and is used to receive the second gas-solid mixture to achieve the first gas-solid separation, so as to obtain the first powder and the third gas-solid mixture; The second air-powder separator is connected between the first air-powder separator and the collector, and is used to receive the third gas-solid mixture and perform a second gas-solid separation to obtain the second powder and exhaust gas.

3. The direct-blown pulverizing unit according to claim 2, characterized in that, The mass of the first powder separated by the first air-powder separator accounts for 50% to 90% of the mass of the powdered material to be combusted.

4. The direct-blown pulverizing unit according to claim 1, characterized in that, The mixing device includes a mixing channel and multiple conveying channels that are connected to the mixing channel. The extending direction of the mixing channel intersects the extending direction of the conveying channels. The mixing channel is connected to the first powder channel and the second powder channel and is used to mix the powdered material to be combusted. The multiple conveying channels are used to distribute the powdered material to multiple ignition points.

5. The direct-blown pulverizing unit according to claim 2, characterized in that, It also includes a pressurizing device, which is connected to the air-powder separation device, for receiving the exhaust gas and pressurizing the exhaust gas to obtain pressurized exhaust gas.

6. The direct-blown pulverizing unit according to claim 1, characterized in that, The cyclone dynamic separation device includes a separation channel, the two ends of which are connected to the grinding device and the air-powder separation device, respectively. The separation channel includes at least a first separation section and a second separation section distributed along the conveying direction of the crushed material. The first separation section is provided with a cyclone component to make the first gas-solid mixture rotate to achieve primary separation and obtain intermediate material. The second separation section is provided with a rotating component, which rotates to make the intermediate material undergo centrifugal motion to obtain the powdered unburned material to achieve secondary separation.

7. A W-type flame combustion boiler system, characterized in that, The system includes a steady-state combustion unit, a dust-removing flue gas unit, and at least one direct-fired pulverizing unit as described in any one of claims 1-6. The pulverizing unit is connected to the steady-state combustion unit to provide powdered combustible material to the boiler system. The steady-state combustion unit includes a boiler body and a vertical concentration-lean separation device disposed on the boiler body. The vertical concentration-lean separation device includes a concentration-side outlet and a lean-side outlet. The vertical concentration-lean separation device is used to move more than 70% of the powdered combustible material to the concentration-side outlet for combustion under gravity during operation, while the remaining powdered combustible material is burned at the lean-side outlet. The steady-state combustion unit is used to burn the powdered combustible material to obtain heat and generate flue gas. The dust-removing flue gas unit is connected to the steady-state combustion unit and is used to remove dust from the flue gas generated by the steady-state combustion unit and discharge it.

8. The W-type flame combustion boiler system according to claim 7, characterized in that, The vertical concentration-to-dilute separation device includes a vertical separation tube and a powder inlet, a dilute side outlet, and a concentrated side outlet connected to the vertical separation tube. The dilute side outlet is located at the top of the vertical separation tube, the concentrated side outlet is located at the bottom of the vertical separation tube, and the powder inlet is located on the side wall of the vertical separation tube. The powder inlet is used to introduce a gas-solid mixture with a preset velocity. The vertical concentration-lean separation device further includes a first control valve located at the light-side outlet for adjusting the pressure at the light-side outlet; and a second control valve located at the concentrated-side outlet for adjusting the pressure at the concentrated-side outlet.

9. The W-type flame combustion boiler system according to claim 7, characterized in that, The boiler body includes a wall portion and a furnace chamber enclosed by the wall portion. The wall portion includes an upper arch portion and a lower arch portion connected to each other. The upper arch portion includes an upper rich side nozzle and an upper secondary air nozzle, and the upper rich side nozzle is connected to the rich side outlet. The lower arch portion includes a lower lean side nozzle and a lower secondary air nozzle, and the lower lean side nozzle is connected to the lean side outlet. The lower secondary air nozzle is configured to be inclined towards the ground when in operation.

10. The W-type flame combustion boiler system according to claim 9, characterized in that, The under-arch light-side nozzle is configured to tilt towards the ground during operation. The under-arch light-side nozzle is divided into multiple light-side nozzle sections by a partition, so that the powdery material to be burned enters the furnace in layers.

11. The W-type flame combustion boiler system according to claim 9, characterized in that, It also includes multiple spaced-apart flame-retardant zones, which are distributed on the inner wall of the furnace.

12. The W-type flame combustion boiler system according to claim 7, characterized in that, The dust removal flue gas unit includes an economizer, a medium-temperature dust removal device, a denitrification device, and a nano-purifier connected in sequence; the economizer is connected to the boiler body and is used to recover the waste heat of the flue gas, the medium-temperature dust removal device is used to remove dust from the flue gas, the denitrification device is used to remove nitrogen oxides from the flue gas, and the nano-purifier is used for secondary dust removal of the flue gas.

13. An operation method for a W-type flame combustion boiler system according to any one of claims 9-11, characterized in that, include: Coal is fed into a direct-fired pulverizing unit to obtain powdered unburned material. The powdered material to be combusted is fed into a vertical concentration-lean separation device, and the pressure P1 at the concentration side outlet and the pressure P2 at the lean side outlet are adjusted to satisfy the following relationship: P1 = 10%P2 ~ 30%P2. The secondary air ratio of the secondary air nozzles above and below the arch is adjusted to (50~60):(40~50).

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