Tangential combustion boiler system capable of flexible operation

Abstract

This application relates to the field of boiler system technology, and provides a tangential combustion boiler system capable of flexible operation. The tangential combustion boiler system includes an interconnected direct-fired pulverizing unit, a fuel-adjustable combustion unit, and a dust-removing flue gas unit. The direct-fired pulverizing unit includes an interconnected grinding device and a cyclone dynamic separator. The fuel-adjustable combustion unit includes a boiler body, a fuel-adjustable burner, and a horizontal cyclone concentration separator. The horizontal cyclone concentration separator is used to adjust the concentration of the powdered material entering the fuel-adjustable burner, which receives and burns the powdered material and can adjust the combustion rate. The dust-removing flue gas unit is used to remove dust from the flue gas generated by the fuel-adjustable combustion unit and discharge it. The tangential combustion boiler system provided by this application can improve the operational flexibility of boiler systems.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of boiler, in particular to a tangentially fired boiler system capable of flexible operation. BACKGROUND

[0002] Thermal power generation refers to a power generation method of converting heat energy generated by combustion of combustible materials into electric energy through power generation devices. In China, coal-fired boiler power generation is an important way of power grid power generation.

[0003] The "Notice on Carrying out National Coal-fired Power Unit Modification and Upgrading" includes flexible modification and energy saving and consumption reduction modification. However, the boiler in the prior art has poor stable combustion effect when operating at low load, and it is difficult to realize flexible operation. SUMMARY

[0004] In view of this, the present application provides a tangentially fired boiler system capable of flexible operation to improve the flexibility of the boiler system operation.

[0005] The present application provides a tangentially fired boiler system capable of flexible operation, which comprises a direct-fired pulverizing unit, a burnable unit with adjustable fuel rate and a dust-removing flue gas unit connected with each other. The direct-fired pulverizing unit comprises a grinding device and a cyclone dynamic separation device connected with each other. The grinding device is used for crushing coal to obtain crushed material. The crushed material is mixed with a first gas flow in the grinding device to obtain a first gas-solid mixture. The cyclone dynamic separation device is used for receiving and separating the first gas-solid mixture to obtain a second gas-solid mixture, which comprises a pulverous fuel material with a preset particle size. The burnable unit with adjustable fuel rate comprises a boiler body, a burnable unit with adjustable fuel rate and a horizontal cyclone dense-thin separator. The burnable unit with adjustable fuel rate is arranged in the boiler body. The horizontal cyclone dense-thin separator is connected between the burnable unit with adjustable fuel rate and the cyclone dynamic separation device. In the working state, the extension direction of the horizontal cyclone dense-thin separator is arranged perpendicularly to the extension direction of the boiler body. The horizontal cyclone dense-thin separator is used for adjusting the concentration of the pulverous fuel material entering the burnable unit with adjustable fuel rate. The burnable unit with adjustable fuel rate is used for receiving and burning the pulverous fuel material. The burnable unit with adjustable fuel rate can adjust the combustion amount of the pulverous fuel material. The dust-removing flue gas unit is used for dust removal and discharge of the flue gas generated by the burnable unit with adjustable fuel rate.

[0006] Optionally, the horizontal cyclone concentration separation device comprises a first separation channel, a first cyclone assembly and an air extraction pipe, the extension direction of the first separation channel is perpendicular to the extension direction of the boiler body, the first cyclone assembly is arranged inside the first separation channel, and is used for making the second gas-solid mixture in a rotating state after entering the first separation channel, the second gas-solid mixture is separated by the centrifugal force to obtain a third gas-solid mixture and a fourth gas-solid mixture, the concentration of the pulverous fuel material in the third gas-solid mixture is higher than that in the fourth gas-solid mixture, and the third gas-solid mixture enters the fuel adjustable burner through the outlet end of the first separation channel.

[0007] Optionally, the first cyclone assembly comprises a plurality of separation blades which are distributed along the circumference of the air extraction pipe, the extension direction of the separation blade forms a first included angle A with the axial direction of the first separation channel, and the first included angle A satisfies the relationship: 25°≤A≤60°.

[0008] Optionally, the fuel adjustable combustion unit further comprises a secondary air nozzle which is communicated with the boiler body, and one end of the air extraction pipe is communicated with the secondary air nozzle, so that the fourth gas-solid mixture is used as the secondary air to organize combustion.

[0009] Optionally, the fuel adjustable burner comprises an area adjustable channel and a primary air nozzle which are connected with each other, the primary air nozzle is communicated with the hearth of the boiler body, the area adjustable channel is communicated with the outlet end of the first separation channel, the area adjustable channel is configured to be adjustable in the channel cross-sectional area, and the area adjustable channel is used for receiving and adjusting the pulverous fuel material and conveying the pulverous fuel material to the hearth through the primary air nozzle.

[0010] Optionally, the gas disturbance device is connected between the fuel adjustable combustion unit and the downstream of the dust removal type flue gas unit, and is used for guiding the dust-removed flue gas into the hearth of the boiler body.

[0011] Optionally, the gas disturbance device comprises a disturbance nozzle which is arranged in the boiler body and is communicated with the hearth, and a flue gas circulating pipeline which is communicated with the downstream of the dust remover at one end and is communicated with the disturbance nozzle at the other end, and a fan for extracting flue gas is arranged on the flue gas circulating pipeline.

[0012] Optionally, the cyclone dynamic separation device comprises a second separation channel which is connected with the grinding device and the horizontal cyclone concentration separation device at two ends along the extension direction of the second separation channel, and the second separation channel comprises at least a first separation section and a second separation section which are distributed along the conveying direction of the crushed material, the first separation section is provided with a second cyclone assembly to make the first gas-solid mixture in a rotating state to realize primary separation to obtain intermediate material, and the second separation section is provided with a rotating component which rotates to make the intermediate material perform centrifugal motion to realize secondary separation.

[0013] Optionally, the boiler body further comprises a plurality of spaced combustion zones, which are distributed on the side of the wall of the boiler body facing the furnace of the boiler body.

[0014] Optionally, the dust-removing flue gas unit comprises, in sequence, an economizer, a medium-temperature dust-removing device, a denitration device, and a nano purifier; the economizer is connected to the boiler body and is used to recover waste heat of the flue gas; the medium-temperature dust-removing device is used to remove dust from the flue gas; the denitration device is used to remove nitrogen oxides in the flue gas; and the nano purifier is used to perform secondary dust removal on the flue gas.

[0015] Compared with the prior art, the embodiments of the present application have at least the following beneficial effects:

[0016] The tangentially-fired boiler system capable of flexible operation according to the embodiments of the present application can obtain the pulverous fuel material including a preset particle size by arranging the direct-fired pulverizing unit. In the firing-intensity-adjustable burner unit, the horizontal-cyclone dense-and-thin separation device is arranged to separate the second gas-solid mixture into dense and thin components, so that the gas-solid mixture containing the dense pulverous fuel material enters the firing-intensity-adjustable burner, and then the firing amount of the pulverous fuel material is adjusted by the firing-intensity-adjustable burner. Since the concentration of the pulverous fuel material entering the firing-intensity-adjustable burner is high, the ignition heat can be reduced, the low-load stable combustion capability can be improved, and the reduced primary air volume can be used for organizing the combustion of the secondary air volume to improve the burnout rate. Meanwhile, the dust-removing flue gas unit can remove dust from the flue gas before discharging the flue gas, so that the flue gas meets the ultra-clean emission requirement. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0018] Figure 1 The connection relationship diagram of the tangentially-fired boiler system according to the embodiments of the present application is provided.

[0019] Figure 2 The overall structure diagram of the horizontal-cyclone dense-and-thin separation device according to the embodiments of the present application is provided.

[0020] Figure 3 The partial structure diagram of the horizontal-cyclone dense-and-thin separation device according to the embodiments of the present application is provided.

[0021] Figure 4 The structure diagram of the firing-intensity-adjustable burner according to the embodiments of the present application is provided.

[0022] Figure 5 The structure diagram of the cyclone dynamic separation device according to the embodiments of the present application is provided.

[0023] Figure 6A structural schematic diagram of a boiler body provided by the embodiment of the present application.

[0024] Reference signs:

[0025] 1, direct-fired pulverizing unit; 3, adjustable combustion unit; 5, dust-removing flue gas unit; 7, gas disturbance device;

[0026] 11, grinding device; 12, cyclone dynamic separation device; 121, second separation passage; 122, first separation section; 123, second cyclone assembly; 124, second separation section; 125, rotating component;

[0027] 31, horizontal cyclone dense-thin separator; 311, first separation passage; 312, first cyclone assembly; 312a, separation blade; 313, air extraction pipe; 32, adjustable burner; 321, area-adjustable passage; 322, primary air nozzle; 323, contraction valve; 33, boiler body; 331, furnace; 331a, main combustion zone; 331b, burnout zone; 332, secondary air nozzle; 71, disturbance nozzle.

[0028] The specific embodiments of the present application have been shown in the above-described drawings, and will be described in more detail hereinafter. These drawings and the written description are not intended to restrict the scope of the present application in any way, but to explain the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0029] In order to make the application purposes, technical solutions and beneficial technical effects of the present application clearer, the present application will be further described in detail in combination with embodiments. It should be understood that the embodiments described in the present specification are only for explaining the present application, and are not intended to limit the present application.

[0030] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the embodiments of the present application should be understood as the usual meanings understood by the skilled in the art to which the embodiments of the present application belong.

[0031] In the description of the embodiments of the present application, the technical terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential” and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and are not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0032] The orientation or positional relationship indicated by “inner”, “outer”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential” and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present application and simplifying the description, and is not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0033] In addition, the technical terms "first", "second" and the like are only for descriptive purposes and should not be construed as indicating or implying relative importance or implying the number of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise explicitly specified and limited.

[0034] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0035] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0036] Thermal power generation refers to a power generation method for converting heat energy generated by combustion of combustible materials into electric energy through power generation power devices. In China, coal-fired boiler power generation in thermal power generation is an important way of power grid power generation.

[0037] The "Notice on Carrying out National Coal-fired Power Unit Modification and Upgrading" includes flexible modification and energy saving and consumption reduction modification. However, the existing boiler has poor stable combustion effect when running at low load, and it is difficult to realize flexible operation.

[0038] In order to solve the problems in the prior art, the present application provides a tangentially fired boiler system capable of flexible operation, which can improve the flexibility of the boiler system operation. The tangentially fired boiler system provided by the present application will be introduced below. First, the tangentially fired boiler system provided by the present application will be introduced.

[0039] Please refer to Figure 1 The tangentially fired boiler system capable of flexible operation provided by the present application comprises a direct-fired pulverizing unit 1, a burnable unit 3 with adjustable fuel and a dust-removing flue gas unit 5 connected with each other.

[0040] The direct-fired pulverizing unit 1 comprises a pulverizing device 11 and a cyclone dynamic separation device 12 connected with each other, the pulverizing device 11 is used for crushing the coal to obtain crushed material, the crushed material is mixed with the first gas flow in the pulverizing device 11 to obtain a first gas-solid mixture, and the cyclone dynamic separation device 12 is used for receiving and separating the first gas-solid mixture to obtain a second gas-solid mixture, the second gas-solid mixture comprises pulverous fuel material of a preset particle size;

[0041] The fuel-adjustable combustion unit 3 comprises a boiler body 33, a fuel-adjustable burner 32 and a horizontal cyclone dense-thin separator 31, the fuel-adjustable burner 32 is arranged in the boiler body 33, the horizontal cyclone dense-thin separator 31 is connected between the fuel-adjustable burner 32 and the cyclone dynamic separation device 12, in the working state, the extension direction of the horizontal cyclone dense-thin separator 31 is arranged perpendicularly to the extension direction of the boiler body 33, the horizontal cyclone dense-thin separator 31 is used for adjusting the concentration of the pulverous fuel material entering the fuel-adjustable burner 32, the fuel-adjustable burner 32 is used for receiving and burning the pulverous fuel material, and the fuel-adjustable burner 32 can adjust the combustion amount of the pulverous fuel material;

[0042] The dust-removing flue gas unit 5 is used for removing dust from the flue gas generated by the fuel-adjustable combustion unit 3 and discharging the flue gas.

[0043] The tangentially-fired boiler refers to a boiler that uses a direct-flow burner to organize combustion in a furnace 331 according to an imaginary tangential circle to form a rotating large fire circle, the rotating direction of the tangential circle can be clockwise or counterclockwise, and the tangentially-fired boiler comprises a commonly-used four-corner tangentially-fired boiler or other tangentially-fired boilers.

[0044] In the embodiment, the direct-fired pulverizing unit 1 is used for providing the pulverous fuel material to the tangentially-fired boiler system, and the pulverous fuel material can be coal powder.

[0045] Exemplarily, the fuel material first enters the pulverizing device 11 and is crushed in the pulverizing device 11 to obtain the crushed material, the fuel material can be fed into the pulverizing device 11 by a coal feeder. The pulverizing device 11 can be connected with a primary air duct, the primary air duct has air introduced by an induced draft fan, or the pulverizing device 11 is connected with a flue gas duct, the flue gas duct has flue gas, or the pulverizing device 11 is simultaneously connected with the primary air duct and the flue gas duct, the first gas flow in the embodiment can be the air introduced by the induced draft fan in the primary air duct, the flue gas in the flue gas duct, or a mixture of the air and the flue gas, preferably, the flue gas in the flue gas duct is pressurized flue gas. The first gas flow is mixed with the crushed material in the pulverizing device 11 to obtain the first gas-solid mixture.

[0046] The first gas-solid mixture enters the cyclone dynamic separation device 12, which separates the larger particle size broken material in the first gas-solid mixture, which can flow back to the grinding device 11 for further crushing. The remaining components of the first gas-solid mixture form a second gas-solid mixture, which can continue to enter the adjustable-burnup combustion unit 3. The second gas-solid mixture includes powdered fuel material of a preset particle size, which can be set according to the combustion needs of the boiler system. The particle size of the powdered fuel material in the second gas-solid mixture can be selected by the cyclone dynamic separation device 12.

[0047] After the second gas-solid mixture enters the adjustable-burnup combustion unit 3, it first enters the horizontal cyclone concentration separation device 31. The horizontal cyclone concentration separation device 31 separates the second gas-solid mixture into a concentrated and a diluted mixture, so that the gas-solid mixture containing the concentrated powdered fuel material enters the adjustable-burnup burner 32, increasing the concentration of the powdered fuel material entering the adjustable-burnup burner 32, thereby reducing the ignition heat of the powdered fuel material and improving the stable combustion capability of the boiler system at low load.

[0048] The extension direction of the horizontal cyclone concentration separation device 31 is perpendicular to the extension direction of the boiler body 33, which can ensure that the direction of the flame formed is perpendicular to the extension direction of the boiler body 33, forming a tangent circle in the horizontal direction.

[0049] Due to the increased concentration of the powdered fuel material entering the burner, the primary air volume will decrease. To ensure the jet velocity of the burner, the adjustable-burnup burner 32 is used in combination with the horizontal cyclone concentration separation device 31. The adjustable-burnup burner 32 is arranged in the boiler body 33 and functions to receive the concentrated powdered fuel material from the horizontal cyclone concentration separation device 31 and burn it. The adjustable-burnup burner 32 can adjust the combustion amount of the powdered fuel material. For example, the combustion amount can be adjusted by adjusting the amount of powdered fuel material entering the adjustable-burnup burner 32, and the adjustment method can be to install a control valve. By adjusting the cross-sectional area of the adjustable-burnup burner 32 through which the powdered fuel material passes, the primary air volume can be matched, so that the jet velocity of the burner reaches the design value, and the reduced primary air volume can reduce the ignition heat of the coal powder, enhancing the stability of combustion. In addition, the reduced primary air volume can be used for secondary air volume organization combustion, improving combustion efficiency.

[0050] The flue gas after combustion enters the dust removal type flue gas unit 5, which functions to remove dust from the flue gas generated by the adjustable-burnup combustion unit 3 before discharging.

[0051] In summary, the tangentially firing boiler system capable of flexible operation has the following advantages. The straight blow type pulverizing unit 1 can obtain the pulverous fuel material with a preset particle size. The horizontal cyclone dense and thin separator 31 is arranged in the fuel quantity adjustable combustion unit 3, so that the second gas-solid mixture is subjected to dense and thin separation, the gas-solid mixture containing the relatively dense pulverous fuel material enters the fuel quantity adjustable burner 32, and then the fuel quantity adjustable burner 32 adjusts the combustion quantity of the pulverous fuel material. Since the concentration of the pulverous fuel material entering the fuel quantity adjustable burner 32 is high, the ignition heat can be reduced, the low load stable combustion capability is improved, and the primary air quantity can be used for the secondary air quantity to organize combustion, the burnout rate is improved, and the dust removal type flue gas unit 5 can discharge the flue gas after dust removal, so that the flue gas meets the ultra-clean emission requirement.

[0052] Please refer to Figure 2 In some embodiments, the horizontal cyclone dense and thin separator 31 comprises a first separation channel 311, a first cyclone assembly 312 and an air extraction pipe 313. The extension direction of the first separation channel 311 is arranged perpendicularly to the extension direction of the boiler body. The first cyclone assembly 312 is arranged inside the first separation channel 311 and used to make the second gas-solid mixture in a rotating state after entering the first separation channel 311. The second gas-solid mixture is subjected to separation under the action of centrifugal force to obtain a third gas-solid mixture and a fourth gas-solid mixture. The concentration of the pulverous fuel material of the third gas-solid mixture is higher than that of the fourth gas-solid mixture. The third gas-solid mixture enters the fuel quantity adjustable burner 32 through the outlet end of the first separation channel 311. One end of the air extraction pipe 313 is communicated with the first separation channel 311 and used to discharge the fourth gas-solid mixture.

[0053] The first cyclone assembly 312 is arranged in the first separation channel 311. The second gas-solid mixture contacts the first cyclone assembly 312 after entering the first separation channel 311, Figure 2 The arrow direction is the entering position of the second gas-solid mixture. The first cyclone assembly 312 is used to make the second gas-solid mixture in a rotating state. Since the centrifugal forces of the components in the second gas-solid mixture are different when rotating, the dense and thin separation is realized. The centrifugal force of the pulverous fuel material with a larger particle size is relatively large, so that the pulverous fuel material can rotate along the inner wall of the horizontal cyclone dense and thin separator in the first separation channel 311 to form the third gas-solid mixture. The centrifugal force of the gas flow and the pulverous fuel material with a smaller particle size is relatively small, so that the pulverous fuel material rotates around the axis of the first separation channel 311 to form the fourth gas-solid mixture. The third gas-solid mixture enters the fuel quantity adjustable burner 32 through the outlet end of the first separation channel 311. One end of the air extraction pipe 313 is communicated with the middle part of the first separation channel 311 and used to discharge the fourth gas-solid mixture.

[0054] By setting the first cyclone assembly 312 to make the second gas-solid mixture in a rotating state, the concentration of the third gas-solid mixture of the pulverized fuel can be much higher than that of the fourth gas-solid mixture, greatly improving the concentration and dilution separation effect of the second mixture. After the third gas-solid mixture enters the burner, the temperature of the boiler on the dense side rises faster, enhancing the effect of maintaining the combustion temperature and ensuring the stability of the combustion under low load. The application can adjust the first cyclone assembly 312 to make the concentration of the third gas-solid mixture of the pulverized fuel reach 9:1 compared with the fourth gas-solid mixture.

[0055] The extension direction of the first separation channel is perpendicular to the extension direction of the boiler body, which can make the third gas-solid mixture enter the furnace at an angle perpendicular to the extension direction of the furnace, and burn in the form of horizontal tangent circle.

[0056] Please refer to Figure 3 In some embodiments, the first cyclone assembly 312 includes a plurality of separation blades 312a distributed along the circumference of the air extraction pipe 313, and the extension direction of the separation blades 312a forms a first included angle A with the axial direction of the first separation channel 311, and the first included angle A satisfies the relationship: 25°≤A≤60°.

[0057] The first included angle A satisfies A≥25°, so that the gas-solid mixture after passing through the separation blades 312a has a sufficient exit angle and can be in a rotating state when reaching the inner wall of the first separation channel 311; the first included angle A satisfies A≤60°, so that the impact force between the gas-solid mixture after passing through the separation blades 312a and the inner wall of the first separation channel 311 is small, avoiding the situation that the pulverized fuel is impacted by the inner wall of the first separation channel 311 to the center of the first separation channel 311, thereby affecting the concentration and dilution separation effect.

[0058] In some embodiments, the horizontal cyclone concentration and dilution separator 31 further includes a deswirler assembly (not shown in the figure), which can be arranged at the discharge end of the first separation channel. The deswirler assembly is used to remove the rotating state of the mixture in the rotating state. Exemplarily, the deswirler assembly includes separation blades arranged along the circumference in the opposite direction of the extension direction of the cyclone assembly. The deswirler assembly can be arranged in other ways as long as the deswirling effect is achieved. Removing the rotating state can avoid the pulverized fuel still in the rotating state when entering the furnace, thereby affecting the normal combustion of the pulverized fuel in the furnace.

[0059] In some embodiments, the burnable unit with adjustable fuel intensity further includes a secondary air nozzle 332 in communication with the boiler body 33, and one end of the air extraction pipe 313 is in communication with the secondary air nozzle 332, for making the fourth gas-solid mixture as secondary air to organize combustion.

[0060] In the embodiments of the present application, the suction pipe 313 is communicated with the secondary air nozzle 332, the fourth gas-solid mixture can be introduced from the secondary air nozzle 332, so that the fourth gas-solid mixture is used as the secondary air to organize combustion. Preferably, the suction pipe 313 is communicated with the secondary air nozzle 332 as a branch pipe, that is, the secondary air nozzle 332 is communicated with a secondary air source in addition to the suction pipe 313, so that the boiler system can flexibly adjust the amount of secondary air. The fourth gas-solid mixture is used as the secondary air, which is beneficial to adjust the position of the flame center in the low load operation state and adjust the temperature of the superheated steam and reheated steam.

[0061] It can be understood that the suction pipe 313 is connected with a fan, and the fan can extract the fourth gas-solid mixture from the first separation channel 311. The fan can be, but is not limited to, a centrifugal fan, an axial fan, an inclined flow fan, or a cross flow fan.

[0062] Please refer to Figure 4 In some embodiments, the heat release adjustable burner 32 comprises an area adjustable channel 321 and a primary air nozzle 322 connected with each other, the primary air nozzle 322 is communicated with the furnace 331 of the boiler body 33, and the area adjustable channel 321 is communicated with the outlet end of the first separation channel 311. The area adjustable channel 321 is configured to be adjustable in cross-sectional area, and is used for receiving and adjusting the pulverized fuel material and delivering the pulverized fuel material to the furnace 331 through the primary air nozzle.

[0063] The heat release adjustable burner 32 used by the heat release adjustable combustion unit 3 uses the area adjustable channel 321, that is, the cross-sectional area of the channel can be adjusted when the pulverized fuel material passes through, so that the flow rate of the primary air can be changed without changing the wind speed of the primary air. The flow rate of the primary air of the area adjustable channel 321 can be adjusted according to the required load of the boiler system. Exemplarily, the area adjustable channel 321 can be realized by setting a contraction valve 323 in the channel. The contraction valve 323 can adjust the cross-sectional area of the area adjustable channel 321 in the axial direction, so as to adjust the delivery amount of the pulverized fuel material and adjust the concentration of the pulverized fuel material.

[0064] The use of the heat release adjustable burner 32 can realize the matching of the speed and concentration of the boiler system 20%-100% BMCR full load operation.

[0065] In some embodiments, the tangentially fired boiler system capable of flexible operation further comprises a gas disturbance device 7 connected between the heat release adjustable combustion unit 3 and the downstream of the dust removal type flue gas unit 5, which is used to guide the dust removal flue gas into the furnace 331 of the boiler body 33.

[0066] By setting the gas disturbance device 7, the air in the furnace 331 of the boiler body 33 can be disturbed, so that the air in the furnace 331 can be fully mixed with the powder to be combusted and burned, and the burnout rate of the powder to be combusted can be effectively improved, the carbon content of fly ash is reduced, and the thermal efficiency of the boiler body 33 is improved.

[0067] It should be noted that the gas disturbance device 7 is an independent structure and does not interfere with the original combustion system of the boiler system, so the gas disturbance device 7 can be used according to the operation of the boiler system or be universal, so that the gas disturbance device 7 has high flexibility.

[0068] In some embodiments, the gas disturbance device 7 comprises: a disturbance nozzle arranged in the boiler body 33 and communicated with the furnace 331; and a flue gas circulating pipeline, one end of which is communicated with the downstream of the dust collector, and the other end is communicated with the disturbance nozzle, and the flue gas circulating pipeline is provided with a fan for extracting flue gas.

[0069] The fan can be but is not limited to a centrifugal fan, an axial fan, an inclined flow fan or a cross flow fan.

[0070] It should be noted that the flue gas extraction point of the flue gas circulating pipeline can be a flue downstream of the dust collector or a clean flue downstream of the desulfurization tower of the boiler system, and the specific position of the flue gas extraction point of the flue gas circulating pipeline 20 is not limited.

[0071] Optionally, the wind pressure of the fan 30 is set to 8-15kPa, for example, the wind pressure of the fan can be but is not limited to 8kPa, 9kPa, 10kPa, 15kPa.

[0072] Optionally, the injection speed of the disturbance nozzle is set to 60-150m / s, for example, the injection speed of the disturbance nozzle can be but is not limited to 60m / s, 80m / s, 100m / s, 120m / s, 150m / s.

[0073] Optionally, the number of disturbance nozzles 71 can be one, two or more, and the specific number of disturbance nozzles 71 is not limited, which can be selected according to the actual situation. When the number of disturbance nozzles 71 is multiple, the multiple disturbance nozzles are arranged at intervals around the circumference of the boiler body 33, and the input ports of the multiple disturbance nozzles 71 are commonly communicated with one flue gas circulating pipeline.

[0074] For example, please refer to Figure 6 The furnace 331 comprises a main combustion zone 331a and a burnout zone 331b from bottom to top, the primary air nozzle 322 and the secondary air nozzle are communicated with the main combustion zone 331a, and the disturbance nozzle is communicated with the burnout zone 331b.

[0075] The powder-like fuel material cannot be ignited in the main combustion zone 331a, and the remaining unburned powder-like fuel material continues to burn in the ignition zone 331b to reduce the concentration of nitrogen oxide emissions. The injection direction of the disturbance nozzle 71 is parallel to the injection direction of the primary air nozzle 322, so that the flue gas injected by the disturbance nozzle 71 and the powder-like fuel material gas stream injected by the primary air nozzle 322 have the same flow path, which can reduce the influence of the disturbance nozzle 71 on the original combustion prevention system of the boiler system, effectively improving the reliability of the gas disturbance device.

[0076] Please refer to Figure 5 In some embodiments, the cyclone dynamic separation device 12 includes a second separation channel 121, which is connected to the grinding device 11 and the horizontal cyclone concentration separation device 31 at both ends along the extension direction of the second separation channel 121. The second separation channel 121 includes at least a first separation section 122 and a second separation section 124 distributed along the conveying direction of the crushed material. The first separation section 122 is provided with a second cyclone assembly 123 to make the first gas-solid mixture in a rotating state to achieve first-stage separation to obtain intermediate material. The second separation section 124 is provided with a rotating component 125, which rotates to make the intermediate material undergo centrifugal motion to achieve second-stage separation.

[0077] The cyclone dynamic separation device 12 separates the crushed material to obtain powder-like fuel material of qualified fineness. Specifically, the cyclone dynamic separation device 12 includes a second separation channel 121, which includes at least a first separation section 122 and a second separation section 124 distributed along the conveying direction of the crushed material. The conveying direction of the crushed material refers to the flow direction of the crushed material from the inlet of the cyclone dynamic separation device 12 to the outlet of the cyclone dynamic separation device 12. After the crushed material enters the cyclone dynamic separation device 12, it first passes through the first separation section 122 for first-stage separation, and then passes through the second separation section 124 for second-stage separation.

[0078] The first separation section 122 is provided with a second cyclone assembly 123, which can make the gas flow of the crushed material entering the cyclone dynamic separation device 12 rotate. Larger particles in the crushed material are subjected to a larger centrifugal force, and the larger particles will slide down along the first channel and be separated out. A powder return pipe can be provided to output the larger particles from the powder return pipe. Smaller particles in the crushed material continue to enter the second separation section 124 as primary material.

[0079] The second cyclone assembly 123 can be the same separation blade as the first cyclone assembly 312, and the included angle between the extension direction of the separation blade and the axis of the second separation channel 121 can be adjusted. It can be understood that the greater the cyclone speed or the greater the cutting angle, the smaller the particles of the pulverized fuel material that can be separated, and the smaller the primary material fineness obtained; conversely, the smaller the cyclone speed or the smaller the cutting angle, the greater the degree of separation of the particles of the pulverized fuel material, and the greater the primary material fineness. In this way, the cyclone speed and the cutting angle of the wind-powder mixture airflow in the first separation section can be adjusted by adjusting the included angle between the separation blade and the axis of the second separation channel 121, and different cyclone speeds and cutting angles can affect the fineness of the pulverized fuel material separation.

[0080] The second separation section 124 is provided 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 forms a rotating separation zone. The primary material in the rotating separation zone is subjected to the centrifugal force applied by the moving impeller, and the pulverized fuel material particles are subjected to the traction force of the airflow. When the centrifugal force acting on the pulverized fuel material particles is greater than the traction force, the pulverized fuel material particles are separated to the outside of the moving impeller; when the centrifugal force acting on the pulverized fuel material particles is less than the traction force, the pulverized fuel material particles are separated to the inside of the moving impeller, and the pulverized fuel material is obtained. It can be understood that the larger the particles of the primary material, the greater the centrifugal force applied by the moving impeller in the rotating separation zone. Therefore, the pulverized fuel material with unqualified fineness of large particles in the primary material is separated to the outside of the moving impeller by the moving impeller, and the pulverized fuel material with unqualified fineness is separated from the cyclone dynamic separation device 12 under the action of gravity and is recycled to the grinding device 11 for regrinding. The pulverized fuel material with qualified fineness of small particles in the primary material is separated by the moving impeller and is output to the horizontal cyclone concentration separation device 31 through the powder outlet pipe. Please refer to Figure 5 , the solid line arrow represents the movement direction of the pulverized fuel material with small particles, and the dashed line arrow represents the movement direction of the pulverized fuel material with large particles.

[0081] In some embodiments, the boiler body 33 further comprises a plurality of spaced-apart combustion support belts, which are distributed on the side of the wall of the boiler body 33 facing the hearth 331 of the boiler body 33.

[0082] In the present application, the spaced-apart combustion support belts are used instead of sheet combustion support belts, which can maintain the uniformity of the temperature of each cross section of the hearth 331 and prevent destructive coking of the hearth 331.

[0083] In some embodiments, the dust removal type flue gas unit 5 comprises a coal economizer, a medium-temperature dust removal device, a denitration device, and a nano purifier connected in sequence.

[0084] In the application, the economizer is connected with the boiler body, specifically, connected with the lower part of the flue of the boiler body, used for recovering the waste heat of the flue gas, and heating the feed water of the boiler body into saturated water under the pressure of the steam drum. The heating surface of the economizer can absorb the heat of the high-temperature flue gas, reduce the exhaust gas temperature of the flue gas, save energy, and improve efficiency.

[0085] The application adds a medium-temperature dust removal device in the dust removal type flue gas unit 5. The medium-temperature dust removal device is used for removing more than 60% of fly ash particles at 400oC-600oC. Preferably, the medium-temperature dust removal device uses the cyclone separation principle for dust removal. The denitration device is an SCR denitration device. Too much fly ash can first have a negative impact on the SCR denitration device, causing ammonia escape to exceed the standard. Excessive ammonia escape can further accelerate the damage of heat storage elements such as the air preheater and the low-temperature economizer, causing problems such as blockage, wear, and corrosion. The medium-temperature dust removal device is arranged between the economizer and the denitration system, which can reduce the resistance of the flue gas fineness, reduce the power consumption of the boiler primary air fan, the air supply fan, and the induced draft fan, reduce the wear of the denitration catalyst and the heat exchange elements of the air preheater, and reduce the unit maintenance cost. The denitration device is used for removing nitrogen oxides in the flue gas, and the nano purifier is used for secondary dust removal of the flue gas. The nano purifier of the application can realize centrifugal separation and through-flow separation using the temperature and pressure of the flue gas itself without consuming external energy, which can remove dust, SO3 aerosol, gypsum droplets, and sulfuric acid rain at low investment and low maintenance cost, so that the flue gas meets the ultra-clean emission requirements.

[0086] The above application content of the application is not intended to describe each disclosed embodiment or each implementation in the application. The following description illustrates exemplary embodiments more specifically. In many places throughout the application, guidance is provided by a series of examples, which can be used in various combinations. In each example, the enumeration is only representative of a group and should not be interpreted as exhaustive.

[0087] The above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed in the application, and these modifications or replacements should be covered within the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A tangentially fired boiler system capable of flexible operation, characterized in that, The tangentially-fired boiler system comprises a direct-fired pulverizing unit, a combustion-intensity-adjustable combustion unit and a dust-removing flue gas unit connected with each other; The direct-fired pulverizing unit comprises a pulverizing device and a cyclone dynamic separation device connected with each other, the pulverizing device is used for crushing coal to obtain crushed material, the crushed material is mixed with a first gas flow in the pulverizing device to obtain a first gas-solid mixture, and the cyclone dynamic separation device is used for receiving and separating the first gas-solid mixture to obtain a second gas-solid mixture comprising pulverous fuel material of a preset particle size. The combustion-intensity-adjustable combustion unit comprises a boiler body, a combustion-intensity-adjustable burner and a horizontal cyclone dense-thin separator, the combustion-intensity-adjustable burner is arranged in the boiler body, the horizontal cyclone dense-thin separator is connected between the combustion-intensity-adjustable burner and the cyclone dynamic separation device, in a working state, an extension direction of the horizontal cyclone dense-thin separator is arranged perpendicularly to an extension direction of the boiler body, the horizontal cyclone dense-thin separator is used for adjusting the concentration of the pulverous fuel material entering the combustion-intensity-adjustable burner, the combustion-intensity-adjustable burner is used for receiving and burning the pulverous fuel material, and the combustion-intensity-adjustable burner can adjust the combustion amount of the pulverous fuel material; the horizontal cyclone dense-thin separator comprises a first separation channel, a first cyclone assembly and an air extraction pipe, the extension direction of the first separation channel is arranged perpendicularly to the extension direction of the boiler body, the first cyclone assembly is arranged inside the first separation channel and used for making the second gas-solid mixture in a rotating state after entering the first separation channel, the second gas-solid mixture is separated by a centrifugal force to obtain a third gas-solid mixture and a fourth gas-solid mixture, the concentration of the pulverous fuel material of the third gas-solid mixture is higher than that of the fourth gas-solid mixture, the third gas-solid mixture enters the combustion-intensity-adjustable burner through an outlet end of the first separation channel, and one end of the air extraction pipe is communicated with the first separation channel and used for discharging the fourth gas-solid mixture. The dust-removing flue gas unit is used for removing dust from flue gas generated by the combustion-intensity-adjustable combustion unit and discharging the flue gas.

2. The tangentially fired boiler system capable of flexible operation according to claim 1, characterized in that, The first cyclone assembly comprises a plurality of separation blades distributed along the air extraction pipe in a circumferential direction, an extension direction of the separation blade forms a first included angle A with an axial direction of the first separation channel, and the first included angle A satisfies a relationship of 25°≤A≤60°.

3. The tangentially fired, flexibly operated, boiler system of claim 1, wherein, The combustion-intensity-adjustable combustion unit further comprises a secondary air injection port communicated with the boiler body, and one end of the air extraction pipe is communicated with the secondary air injection port, so that the fourth gas-solid mixture is used as secondary air for combustion.

4. The tangentially fired, flexibly operated, boiler system of claim 1, wherein, The fuel-adjustable combustor comprises mutually connected area-adjustable channels and primary air nozzles, the primary air nozzles are communicated with a hearth of the boiler body, the area-adjustable channels are communicated with outlet ends of the first separation channels, the area-adjustable channels are configured to be adjustable in channel cross-sectional area, and the area-adjustable channels are used for receiving and adjusting pulverized fuel materials and delivering the pulverized fuel materials to the hearth through the primary air nozzles.

5. The tangentially fired, flexibly operated, boiler system of claim 1, wherein, Further comprising a gas disturbance device connected between the fuel-adjustable combustion unit and downstream of the dust-removing flue gas unit, used for guiding the dust-removed flue gas into the hearth of the boiler body.

6. The tangentially fired, flexibly operable, boiler system of claim 5, wherein, The gas disturbance device comprises: A disturbance nozzle arranged in the boiler body and communicated with the hearth; And a flue gas circulating pipeline communicated at one end with downstream of the dust remover and at the other end with the disturbance nozzle, and provided with a fan for extracting the flue gas.

7. The tangentially fired, flexibly operable, boiler system of claim 1, wherein, The cyclone dynamic separation device comprises a second separation channel, the second separation channel is connected with the grinding device and the horizontal cyclone concentration separation device at two ends along the extension direction thereof, the second separation channel comprises 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 second cyclone assembly to make the first gas-solid mixture in a rotating state to achieve primary separation to obtain intermediate material, and the second separation section is provided with a rotating component, the rotating component rotates to make the intermediate material perform centrifugal motion to achieve secondary separation.

8. The tangentially fired, flexibly operated, boiler system of claim 1, wherein, The boiler body further comprises a plurality of interval arranged combustion support belts, the combustion support belts are distributed on a side of the wall of the boiler body facing the hearth of the boiler body.

9. The tangentially fired, flexibly operable, boiler system of claim 1, wherein, The dust-removing flue gas unit comprises a economizer, a medium-temperature dust removal device, a denitration device and a nano purifier connected in sequence; the economizer is connected with the boiler body and used for recovering waste heat of the flue gas, the medium-temperature dust removal device is used for dust removal of the flue gas, the denitration device is used for removing nitrogen oxides in the flue gas, and the nano purifier is used for secondary dust removal of the flue gas.

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