Blast cap of circulating fluidized bed boiler capable of balancing bed temperature distribution and circulating fluidized bed boiler

Abstract

The invention discloses an air cap of a circulating fluidized bed boiler capable of balancing bed temperature distribution and the circulating fluidized bed boiler, the air cap comprises an air guide pipe, an air cap outer cover and a heat conduction pipe, and the air guide pipe is provided with an air inlet and a flow guide port which are communicated; the hood outer cover is arranged on the outer side of the air guide pipe in a sleeving mode and provided with an air outlet, a circulation space is formed between the air guide pipe and the hood outer cover, and the flow guide opening communicates with the air outlet through the circulation space; the heat conduction pipe and the hood outer cover are arranged in the axis direction of the hood outer cover, and the heat conductivity of the end, close to the hood outer cover, of the heat conduction pipe is smaller than that of the end, away from the hood outer cover, of the heat conduction pipe. The end, close to the hood outer cover, of the heat conduction pipe is used for preventing heat in the upper area of the bed material from being transferred downwards, and the end, away from the hood outer cover, of the heat conduction pipe is used for transferring heat in the lower area of the bed material upwards, so that the temperature uniformity of the bed material is facilitated, and the surface temperature of the bed material is increased; and more heat can be transferred to the heating surface of the hearth during banking fire, so that the steam parameter is improved, and the banking fire duration is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power generation, in particular to a wind cap of a circulating fluidized bed boiler for balancing bed temperature distribution and a circulating fluidized bed boiler. BACKGROUND

[0002] The circulating fluidized bed boiler has a large amount of bed material and castable, so it has a large heat storage capacity and can realize the operation of fire suppression. It is of great significance to use the fire suppression of the circulating fluidized bed unit for grid peak shaving and consumption of new energy power. However, one bottleneck of the fire suppression of the circulating fluidized bed boiler is that the fire suppression time is short, which cannot meet the requirement of the dispatching on the fire suppression time.

[0003] Due to the low thermal conductivity of the bed material, during the fire suppression, the temperature distribution of the bed material along the vertical direction presents the distribution characteristics of high in the middle and low on both sides, that is, the temperature of the bed material in the upper surface area of the bed material drops very quickly, which is much lower than the center temperature of the bed material and the average temperature of the bed material.

[0004] Since the heat exchange between the upper surface of the bed material and the water wall is mainly in the form of radiation during the fire suppression, and the radiation heat transfer is proportional to the absolute temperature of the heat transfer surface, as the temperature of the upper surface of the bed material decreases, the heat transfer amount decreases significantly, so that the steam parameters cannot meet the operation requirements of the steam turbine. That is, due to the low thermal conductivity of the bed material, a large amount of heat of the bed material cannot be effectively released, resulting in a decrease in the heat transfer amount between the bed material and the heat transfer surface, and the steam parameters cannot meet the operation of the unit, thereby greatly reducing the fire suppression time of the unit and significantly affecting the ability of the circulating fluidized bed unit to suppress the fire.

[0005] Therefore, how to solve the problem of uneven temperature distribution of the bed material during the fire suppression of the circulating fluidized bed boiler, which leads to low temperature in the upper surface area of the bed material and cannot effectively provide heat to the heating surface in the circulating fluidized bed boiler, is a technical problem to be solved by those skilled in the art. SUMMARY

[0006] Therefore, the present application provides a magnetic field adjusting motor which can dynamically and quickly respond and achieve efficient and deep magnetic field adjustment. In addition, the present application also provides a power consumption device having the above-mentioned magnetic field adjusting motor and a magnetic field adjusting and coordinating control method of the magnetic field adjusting motor.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0008] A wind cap of a circulating fluidized bed boiler for balancing bed temperature distribution, comprising:

[0009] A wind guide pipe, one end of the wind guide pipe is provided with an air inlet, and the other end is provided with a flow guide opening, the flow area of the flow guide opening is smaller than the flow area of the air inlet, and the air inlet and the flow guide opening are in communication;

[0010] A hood cover is sleeved outside the air duct, and the hood cover has an air outlet; the air duct and the hood cover have a flow-through space, and the air guide hole communicates with the air outlet through the flow-through space;

[0011] A heat conduction pipe is arranged along the axial direction of the hood cover, and the heat conduction pipe is arranged at one end of the hood cover away from the air inlet; the heat conductivity of the end of the heat conduction pipe close to the hood cover is smaller than the heat conductivity of the end of the heat conduction pipe away from the hood cover.

[0012] Preferably, in the hood of the circulating fluidized bed boiler for balancing the bed temperature distribution, the heat conduction pipe comprises a first chamber and a second chamber distributed along the axial direction, the first chamber and the second chamber are isolated from each other, the first chamber is a sealed chamber, the second chamber is a hollow structure, and the heat conductivity of the first chamber is greater than that of the second chamber.

[0013] Preferably, in the hood of the circulating fluidized bed boiler for balancing the bed temperature distribution, the first chamber is filled with a heat-conducting filler, and the heat conductivity of the heat-conducting filler is greater than that of air.

[0014] Preferably, in the hood of the circulating fluidized bed boiler for balancing the bed temperature distribution, the first chamber is in a vacuum state.

[0015] Preferably, in the hood of the circulating fluidized bed boiler for balancing the bed temperature distribution, the size of the second chamber along the axial direction is smaller than the size of the first chamber along the axial direction.

[0016] Preferably, in the hood of the circulating fluidized bed boiler for balancing the bed temperature distribution, the air duct is provided with a plurality of air guide holes in the circumferential direction;

[0017] And / or, the circumferential side wall of the hood cover is provided with a plurality of air outlets.

[0018] Preferably, in the hood of the circulating fluidized bed boiler for balancing the bed temperature distribution, the top of the air duct along the axial direction abuts and connects with the top of the hood cover along the axial direction, and the bottom of the air duct along the axial direction protrudes out of the hood cover.

[0019] The air guide hole is located on the side wall of the top of the air duct, and the air inlet is located at the bottom of the air duct.

[0020] Preferably, in the hood of the circulating fluidized bed boiler for balancing the bed temperature distribution, the air outlet is located at the lower part of the hood cover along the axial direction,

[0021] And the position of the flow guide hole along the axis direction is higher than the position of the air outlet along the axis direction.

[0022] A circulating fluidized bed boiler, comprising a hood and a furnace body, the hood being the hood of the circulating fluidized bed boiler with balanced bed temperature distribution as claimed in any one of the preceding claims, the air inlet of the hood being in communication with the primary air of the furnace body, and the heat conducting pipe of the hood being inserted into the bed material in the furnace body.

[0023] Preferably, in the circulating fluidized bed boiler, the bed material of the furnace body comprises a lower region, a middle region and an upper region arranged in sequence along the axis direction of the furnace body, and the lower region is close to the primary air chamber of the furnace body.

[0024] The first chamber of the heat conducting pipe is located in the middle region and the upper region, and the second chamber of the heat conducting pipe is located in the lower region.

[0025] The axis direction of the furnace body is parallel to the axis direction of the hood cover of the hood.

[0026] The hood of the circulating fluidized bed boiler with balanced bed temperature distribution disclosed in the embodiments of the present application can increase the length of the hood by adding a heat conducting pipe at the upper part of the hood cover. After the hood is applied to the circulating fluidized bed, the hood can have a larger length extending into the bed material, which is beneficial to increase the heat conducting area of the hood and increase the heat storage capacity of the hood.

[0027] The heat conductivity of the end of the heat conducting pipe close to the hood cover is set to be smaller than the heat conductivity of the end of the heat conducting pipe away from the hood cover. The first chamber can prevent the heat in the upper region of the bed material from being transferred downward, and the second chamber can transfer the heat in the lower region of the bed material upward, which is beneficial to ensure the uniformity of the bed material temperature. In addition, the temperature of the surface of the bed material can also be increased, so that more heat can be transferred to the furnace heating surface during the pressure holding period, the steam parameters can be improved, and the pressure holding time can be prolonged.

[0028] In addition, the embodiments of the present application also disclose a circulating fluidized bed boiler with the hood of the circulating fluidized bed boiler with balanced bed temperature distribution as described above. Therefore, the circulating fluidized bed boiler with the hood of the circulating fluidized bed boiler with balanced bed temperature distribution also has the technical effects as described above, and details are not repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0030] Figure 1 A front view of a cross section of a wind cap of a circulating fluidized bed boiler with an even bed temperature distribution according to an embodiment of the present application;

[0031] Figure 2 A front view of a cross section of a partial structure of a wind cap of a circulating fluidized bed boiler with an even bed temperature distribution according to an embodiment of the present application;

[0032] Figure 3 A front view of a cross section of a first structure of a heat conducting pipe of a wind cap of a circulating fluidized bed boiler with an even bed temperature distribution according to an embodiment of the present application;

[0033] Figure 4 A front view of a cross section of a second structure of a heat conducting pipe of a wind cap of a circulating fluidized bed boiler with an even bed temperature distribution according to an embodiment of the present application;

[0034] Figure 5 A schematic view of a partial structure of a circulating fluidized bed according to an embodiment of the present application.

[0035] wherein,

[0036] 1 - air guide pipe, 2 - wind cap cover, 3 - heat conducting pipe, 4 - heat conducting filler;

[0037] 11 - air inlet, 12 - air guide hole, 21 - air outlet; 31 - first chamber, 32 - second chamber, 33 - partition, 321 - through hole;

[0038] 101 - lower region, 102 - middle region, 103 - upper region. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without any creative work fall within the protection scope of the present application.

[0040] Hereinafter, the terms "first" and "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features.

[0041] The circulating fluidized bed boiler has a large amount of bed material and castable, and thus has a large heat storage capacity and can realize the fire banking operation. The fire banking peak shaving of the circulating fluidized bed unit is of great significance for grid peak shaving and new energy power consumption. However, a bottleneck of the fire banking peak shaving of the circulating fluidized bed boiler is that the fire banking time is short and cannot meet the requirement of the fire banking time length of the dispatch.

[0042] The factors affecting the fire banking time length include that during the fire banking, the bed material of the boiler and the water-cooled wall and other heating surfaces in the furnace perform radiation heat exchange, and the temperature decreases. However, since the thermal conductivity coefficient of the bed material is only 0.1 W / (m·K)-2 W / (m·K), the thermal conductivity coefficient of the bed material is low, and the heat in the bed material cannot be released in time.

[0043] In addition, due to the low thermal conductivity coefficient of the bed material, during the fire banking, the temperature distribution of the bed material along the vertical direction presents the distribution characteristics that the middle part is high and the two sides are low, that is, the temperature of the bed material in the upper surface region of the bed material decreases very fast and is far lower than the center temperature of the bed material and the average temperature of the bed material. Since the heat exchange mode between the bed material in the upper surface region of the bed material and the water-cooled wall is mainly radiation heat exchange during the fire banking, and the radiation heat exchange amount is proportional to the fourth power difference of the absolute temperature of the heat exchange surface, with the decrease of the temperature of the bed material in the upper surface region of the bed material, the heat exchange amount decreases significantly, so that the steam parameters cannot meet the operation requirements of the steam turbine. Even if the average temperature of the bed material is very high, due to the decrease of the surface temperature of the bed material, a large amount of heat cannot be effectively released, the heat exchange amount decreases, and the steam parameters cannot meet the operation of the unit, thereby greatly reducing the fire banking time length of the unit and significantly affecting the fire banking peak shaving capacity of the fluidized bed unit.

[0044] In order to solve the problem that the temperature distribution of the bed material is uneven during the fire banking of the circulating fluidized bed boiler, the temperature of the upper surface region of the bed material is low, and the bed material cannot effectively provide heat for the heating surface in the furnace of the circulating fluidized bed boiler, the embodiment of the present application proposes a wind cap of a circulating fluidized bed boiler for balancing bed temperature distribution.

[0045] The wind cap of the circulating fluidized bed boiler for balancing bed temperature distribution of the embodiment can carry the heat in the middle region of the bed material to the upper surface of the bed material during the fire banking process, so as to strengthen the heat exchange amount between the surface of the bed material and the water-cooled wall and the screen heating surface, improve the steam parameters, and prolong the fire banking time length.

[0046] As shown in Figure 1 The wind cap of the circulating fluidized bed boiler for balancing bed temperature distribution of the embodiment includes a wind guide pipe 1, a wind cap outer cover 2 and a heat conduction pipe 3.

[0047] The wind cap outer cover 2 and the heat conduction pipe 3 are arranged along the axis direction of the wind cap, and the wind guide pipe 1 extends into the inside of the wind cap outer cover 2.

[0048] In combination with Figure 1and Figure 2 As shown in the drawings, the air guide pipe 1 has an air inlet 11 at one end along the axial direction of the air guide pipe 1, and has a flow guide hole 12 at the other end along the axial direction of the air guide pipe 1, and the flow guide hole 12 is arranged along the circumferential direction of the air guide pipe 1. It can be understood that the circumferential direction of one end of the air guide pipe 1 has a plurality of through holes, which are the flow guide holes 12, and the number of flow guide holes 12 can be set according to different needs.

[0049] The flow area of the flow guide hole 12 of the embodiment is smaller than the flow area of the air inlet 11, so that the flow rate of the primary air entering the air inlet 11 can be increased during the process of passing through the flow guide hole 12.

[0050] Optionally, the flow guide holes 12 can be distributed in multiple layers along the axial direction of the air guide pipe 1, and the flow guide holes 12 of adjacent layers can be arranged in a staggered manner along the axial direction.

[0051] The air cap cover 2 is sleeved on the outside of the air guide pipe 1, and the top of the air guide pipe 1 along the axial direction (the end away from the air inlet 11) abuts against the top of the air cap cover 2 and is fixed. Optionally, the top of the air guide pipe 1 is welded to the air cap cover 2.

[0052] In some embodiments, the air guide pipe 1 and the air cap cover 2 can be coaxially arranged, and the axis of the air guide pipe 1 and the air cap cover 2 is the axis of the air cap.

[0053] The air cap cover 2 and the air guide pipe 1 have a gap in the radial direction, which can be understood as the inner diameter of the air cap cover 2 being greater than the outer diameter of the air guide pipe 1, so that a flow space is formed between the air cap cover 2 and the air guide pipe 1.

[0054] The lower end of the air cap cover 2 along the axial direction is in sealing contact with the air guide pipe 1, so that the flow space formed between the air cap cover 2 and the air guide pipe 1 is closed.

[0055] The air cap cover 2 is provided with an air outlet 21 along the circumferential direction, and the air outlet 21 is in communication with the flow space, so that the air cap forms an air duct of the air inlet 11, the flow guide hole 12, the flow space and the air outlet 21. The primary air enters the air cap through the air inlet 11, and the flow rate increases after passing through the small-diameter flow guide hole 12, and is sprayed out through the air outlet 21, forming an air cushion layer at the bottom of the bed material of the circulating fluidized bed, so that the bed material particles are uniformly fluidized.

[0056] Optionally, the air outlet 21 is arranged at the lower part of the air cap cover 2 along the axial direction, and the air outlet 21 is located on the side wall of the air cap cover 2 and is close to the lower part. It can be known from the positions of the flow guide hole 12 and the air outlet 21 that the flow guide hole 12 and the air outlet 21 are arranged in a staggered manner along the axial direction of the air cap. Optionally, the position of the flow guide hole 12 is higher than the position of the air outlet 21 along the axial direction.

[0057] In some embodiments, the air outlets 21 can be uniformly arranged along the circumference of the air cap cover 2 to improve the uniformity of the air cap in fluidizing the bed material.

[0058] In combination Figure 1 and Figure 3 As shown in the drawings, the heat pipe 3 is arranged along the axial direction of the air cap cover 2, and optionally, the heat pipe 3 is arranged at the top of the air cap cover 2 along the axial direction (away from the air inlet 11). For example, the heat pipe 3 is fixedly connected to the top of the air cap cover 2, for example, the heat pipe 3 is welded to the air cap cover 2.

[0059] The heat pipe 3 extends along the axial direction of the air cap, and a partition plate 33 is arranged in the heat pipe 3, and the partition plate 33 divides the inside of the heat pipe 3 into a first chamber 31 and a second chamber 32, and the first chamber 31 and the second chamber 32 are isolated from each other.

[0060] The first chamber 31 and the second chamber 32 are arranged along the axial direction of the air cap, and the second chamber 32 is located between the first chamber 31 and the air cap cover 2. It can be understood that along the axial direction of the air cap, the second chamber 32 is close to the air cap cover 2.

[0061] The first chamber 31 of the embodiment is a sealed chamber, and the heat pipe 3 has a ventilation opening 321 on the side wall at the second chamber 32, that is, the ventilation opening 321 communicates with the second chamber 32.

[0062] The second chamber 32 communicates with the outside, which can increase the heat exchange efficiency between the second chamber 32 and the outside, and reduce the thermal conductivity of the second chamber 32. It can be understood that the thermal conductivity of the second chamber 32 of the heat pipe 3 is set to be less than the thermal conductivity of the first chamber 31 of the heat pipe 3, that is, the thermal conductivity of the end of the heat pipe 3 close to the air cap cover 2 is less than the thermal conductivity of the end of the heat pipe 3 away from the air cap cover 2.

[0063] The air cap of the balanced bed temperature distribution circulating fluidized bed boiler of the embodiment increases the heat pipe 3 at the upper part of the air cap cover 2, which can increase the length of the air cap, so that the air cap can be inserted into the bed material with a larger length, which is beneficial to increase the heat conduction area of the air cap and increase the heat storage capacity of the air cap.

[0064] After the air cap is applied to the circulating fluidized bed, the air cap can be inserted into the bed material with a larger length; the thermal conductivity of the end of the heat pipe 3 close to the air cap cover 2 is set to be less than the thermal conductivity of the end of the heat pipe 3 away from the air cap cover 2, which can prevent the heat of the upper region of the bed material from being transmitted downward by using the first chamber 31, and the heat of the lower region of the bed material can be transmitted upward by using the second chamber 32, which is beneficial to ensure the uniformity of the bed material temperature, in addition, it can also improve the temperature of the surface of the bed material, so that more heat can be transmitted to the furnace heating surface during the fire pressing period, the steam parameters can be improved, and the fire pressing time can be prolonged.

[0065] Optionally, the air vents 321 are multiple and arranged along the circumference of the heat conduction pipe 3. For example, the air vents 321 are four and uniformly arranged along the circumference of the heat conduction pipe 3. Of course, the number of the air vents 321 in the embodiment is not limited to four, and can be one, two or more.

[0066] The increase of the number of the air vents 321 can reduce the weight of the air cap, reduce the cost, and increase the heat exchange efficiency between the second chamber 32 and the outside, and reduce the downward heat transfer of the middle region of the bed material.

[0067] It should be noted that the shape, number and arrangement position of the air vents 321 can be set according to different needs. For example, the air vents 321 can be strip-shaped holes extending along the axis direction of the air cap, and the air vents 321 can be arranged in a staggered manner along the circumference of the heat conduction pipe 3.

[0068] The material of the heat conduction pipe 3 in the embodiment can be a metal material such as aluminum, or other heat conduction materials, and all are within the protection scope. The partition plate 33 in the embodiment can be a heat insulation material such as glass fiber.

[0069] In combination with Figure 5 As shown in the scene of the air cap of the circulating fluidized bed boiler with the balanced bed temperature distribution in the embodiment, when the circulating fluidized bed boiler is on fire, the first chamber 31 of the heat conduction pipe 3 of the air cap is opposite to the middle region 102 and the upper region 103 of the bed material in the dense phase zone along the height direction of the boiler; and the second chamber 32 of the heat conduction pipe 3 is opposite to the lower region 101 of the bed material along the height direction of the boiler.

[0070] It should be noted that the upper region 103, the middle region 102 and the lower region 101 of the bed material in the dense phase zone in the embodiment can be set according to different needs, and there is no obvious boundary, which can be set by the person skilled in the art according to the heat exchange requirement.

[0071] The second chamber 32 can reduce the heat transfer from the middle region 102 and the upper region 103 of the bed material to the lower region 101 of the bed material, and even can avoid the heat transfer from the middle region 102 and the upper region 103 of the bed material to the lower region 101 of the bed material, thereby facilitating the upward diffusion of the heat of the middle region 102 of the bed material.

[0072] The first chamber 31 has a high thermal conductivity, and can transmit the heat of the middle region 102 of the bed material upward to the upper region 103 of the bed material. In addition, the first chamber 31 can directly or indirectly transmit the heat of the bed material to the furnace heating surface by using the high thermal conductivity, thereby being able to transmit more heat to the furnace heating surface during the fire, improving the steam parameter, and prolonging the fire time.

[0073] In combination with Figure 1 and Figure 4In the shown embodiment, the first chamber 31 is filled with a heat-conducting filler 4, which can be, for example, aluminum or boron nitride.

[0074] The filling of the first chamber 31 with the heat-conducting filler 4 can improve the heat conductivity of the first chamber 31. Specifically, the heat conductivity of aluminum is much higher than that of the bed material. In an example, the heat conductivity of aluminum is as high as 237 W / (m·K), while the heat conductivity of the ash varies with the composition and temperature and is typically between 0.1 W / (m·K) and 2 W / (m·K). Therefore, the heat-conducting performance of aluminum is significantly better than that of the ash, which is conducive to the rapid transfer and storage of heat. During the process of pressing the fire, the heat of the bed material in the middle region can be transferred to the bed material in the upper region through the first chamber 31 of the heat-conducting pipe 3 of the wind cap or directly radiated to the hearth by the heat-conducting pipe 3 of the wind cap.

[0075] In the embodiment, the heat-conducting filler 4 filled in the first chamber 31 is selected to be aluminum, which can ensure a large heat conductivity and good heat transfer effect while reducing the weight of the wind cap. In addition, the selection of aluminum as the heat-conducting filler 4 can also utilize the phase change of aluminum to increase the heat exchange effect.

[0076] Specifically, during the process of pressing the fire, the temperature of the bed material of the circulating fluidized bed generally decreases from 850°C to about 600°C, and the melting point of aluminum is generally about 660.32°C. Therefore, the aluminum filled in the first chamber 31 is just in the temperature range of the bed material during the pressing of the fire. When the temperature of the bed material decreases to the melting point of aluminum, the aluminum in the heat-conducting pipe 3 condenses from a liquid state to a solid state, i.e., a phase change occurs. A large amount of heat is released during the phase change of aluminum, and the calculated heat released during the condensation of aluminum is about 396 kJ / kg. The released heat is transferred to the heating surface of the boiler, which can significantly improve the steam parameters of the boiler and increase the length of time during which the fire is pressed.

[0077] In some embodiments, the first chamber 31 is vacuumized, i.e., after the first chamber 31 is filled with the heat-conducting filler 4, a vacuumizing operation is performed to make the first chamber 31 in a vacuum state. After the vacuumizing of the first chamber 31, the heat conductivity of the first chamber 31 filled with the heat-conducting filler 4 can be further increased. In addition, after the vacuumizing of the interior of the first chamber 31 of the heat-conducting pipe 3, the expansion stress caused by the temperature change of the gas in the interior of the first chamber 31 can be avoided.

[0078] In some embodiments, the size of the first chamber 31 along the axis direction of the wind cap is greater than the length of the second chamber 32 along the axis direction of the wind cap, so as to increase the heat exchange area of the first chamber 31 of the wind cap and improve the temperature of the upper region 103 of the bed material.

[0079] In combination with Figure 5As shown, the embodiment of the present application also discloses a circulating fluidized bed boiler, comprising a furnace body and a wind cap, wherein the hearth of the furnace body comprises a dense phase zone and bed material in the dense phase zone. Along the height direction of the furnace body, the bed material comprises a lower region 101, a middle region 102 and an upper region 103.

[0080] The wind cap of the circulating fluidized bed boiler is the wind cap of the circulating fluidized bed boiler with the balanced bed temperature distribution disclosed in the above embodiment, and therefore, the circulating fluidized bed boiler with the wind cap of the circulating fluidized bed boiler with the balanced bed temperature distribution also has all the technical effects described above, which will not be described herein again.

[0081] The wind cap is arranged in the boiler, and the air inlet 11 of the wind cap is communicated with the primary air of the boiler, the air guide pipe 1 and the outer cover 2 of the wind cap extend into the lower region 101 of the bed material, the second chamber 32 of the heat guide pipe 3 extends into the lower region 101 of the bed material, and the first chamber 31 of the heat guide pipe 3 extends into the middle region 102 and the upper region 103 of the bed material.

[0082] The wind cap of the circulating fluidized bed boiler of the embodiment increases the heat guide pipe 3 at the upper part of the outer cover 2 of the wind cap, which can increase the length of the wind cap, thereby increasing the length of the wind cap extending into the bed material, being beneficial to increasing the heat conduction area of the wind cap and increasing the heat storage capacity of the wind cap.

[0083] In addition, the heat conduction rate of the end of the heat guide pipe 3 close to the outer cover 2 of the wind cap is arranged to be smaller than the heat conduction rate of the end of the heat guide pipe 3 away from the outer cover 2 of the wind cap, which can prevent the heat of the upper region of the bed material from being transferred downward by the first chamber 31 and transfer the heat of the lower region of the bed material upward by the second chamber 32, being beneficial to ensuring the uniformity of the bed material temperature, and in addition, the temperature of the surface of the bed material can be increased, thereby being able to transfer more heat to the heating surface of the hearth during the pressure holding period, improving the steam parameter, and prolonging the pressure holding time.

[0084] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0085] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wind cap for a circulating fluidized bed boiler with balanced bed temperature distribution, characterized in that, include: The air duct (1) has an air inlet (11) at one end and a flow guide (12) at the other end. The flow area of ​​the flow guide (12) is smaller than the flow area of ​​the air inlet (11). The air inlet (11) and the flow guide (12) are connected. The wind cap cover (2) is fitted on the outside of the air guide pipe (1) and has an air outlet (21); there is a flow space between the air guide pipe (1) and the wind cap cover (2) and the air guide port (12) is connected to the air outlet (21) through the flow space; A heat pipe (3) is arranged along the axial direction of the hood cover (2) and the heat pipe (3) is located at the end of the hood cover (2) away from the air inlet (11). The thermal conductivity of the end of the heat pipe (3) near the hood cover (2) is less than that of the end away from the hood cover (2).

2. The air cap of the circulating fluidized bed boiler with balanced bed temperature distribution according to claim 1, characterized in that, The heat pipe (3) includes a first chamber (31) and a second chamber (32) distributed along the axial direction. The first chamber (31) and the second chamber (32) are isolated from each other. The first chamber (31) is a sealed chamber, and the second chamber (32) is a hollow structure. The thermal conductivity of the first chamber (31) is greater than that of the second chamber (32).

3. The air cap of the circulating fluidized bed boiler with balanced bed temperature distribution according to claim 2, characterized in that, The first chamber (31) is filled with thermally conductive filler (4), and the thermal conductivity of the thermally conductive filler (4) is greater than that of air.

4. The air cap of the circulating fluidized bed boiler with balanced bed temperature distribution according to claim 3, characterized in that, The first chamber (31) is in a vacuum state.

5. The air cap of the circulating fluidized bed boiler with balanced bed temperature distribution according to any one of claims 2 to 4, characterized in that, The second chamber (32) has a smaller dimension along the axial direction than the first chamber (31) along the axial direction.

6. The air cap of a circulating fluidized bed boiler with balanced bed temperature distribution according to any one of claims 1 to 4, characterized in that, The air duct (1) is provided with a plurality of air inlets (12) in the circumferential direction. And / or, the circumferential sidewall of the hood cover (2) is provided with a plurality of air outlets (21).

7. The air cap of the circulating fluidized bed boiler with balanced bed temperature distribution according to any one of claims 1 to 4, characterized in that, The top of the air guide pipe (1) along the axial direction abuts and connects with the top of the wind cap cover (2) along the axial direction, and the bottom of the air guide pipe (1) along the axial direction extends outward from the wind cap cover (2). The air guide (12) is located on the top side wall of the air guide pipe (1), and the air inlet (11) is located at the bottom of the air guide pipe (1).

8. The air cap of the circulating fluidized bed boiler with balanced bed temperature distribution according to claim 7, characterized in that, The air outlet (21) is located at the lower part of the outer cover (2) along the axis. Furthermore, the position of the guide port (12) along the axial direction is higher than the position of the air outlet (21) along the axial direction.

9. A circulating fluidized bed boiler, characterized in that, Includes an air cap and a furnace body, wherein the air cap is the air cap of a circulating fluidized bed boiler with balanced bed temperature distribution as described in any one of claims 1 to 8, the air inlet (11) of the air cap is connected to the primary air of the furnace body, and the heat-conducting pipe (3) of the air cap is inserted into the bed material inside the furnace body.

10. The circulating fluidized bed boiler according to claim 9, characterized in that, The bed material of the furnace body includes a lower region (101), a middle region (102) and an upper region (103) arranged sequentially along the axial direction of the furnace body, wherein the lower region (101) is close to the primary air chamber of the furnace body; The first chamber (31) of the heat pipe (3) is located in the middle region (102) and the upper region (103); the second chamber (32) of the heat pipe (3) is located in the lower region (101). The axial direction of the furnace body is parallel to the axial direction of the wind cap outer cover (2).

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