Adjustment Structure of Circulating Flow Rate of Circulating Fluidized Bed Boiler

Abstract

The present invention discloses a structure for regulating the circulation flow rate of a circulating fluidized bed boiler, comprising a cyclone separator, a ventilation pipe, and an air intake and exhaust assembly. The ventilation pipe passes through the side wall of the material leg of the cyclone separator, one end of the ventilation pipe is located at the inner upper end of the material leg and has a vent, and the other end of the ventilation pipe is located outside the material leg; the air intake and exhaust assembly is connected to the other end of the ventilation pipe, and is used to introduce air into the inner upper end of the material leg through the ventilation pipe to increase the pressure at the inner upper end of the material leg, and to exhaust air from the inner upper end of the material leg through the ventilation pipe to reduce the pressure at the inner upper end of the material leg. The present invention can regulate the circulation flow rate of a circulating fluidized bed boiler, and has a fast response speed, is easy to adjust, and is simple to operate.

Description

Technical Field

[0001] The invention relates to the technical field of circulating fluidized bed boilers, in particular to a regulating structure for the circulation flow rate of a circulating fluidized bed boiler. Background Art

[0002] In order to meet the "dual carbon" goals, my country's power system is facing transformation. Circulating fluidized bed boilers will also play an important role in the new power system due to their advantages such as wide fuel, low pollution emissions, and stable operation at low load. Unleashing deep peak-shaving potential and improving operational flexibility are important directions for the development of circulating fluidized bed boiler units.

[0003] The key to load regulation of circulating fluidized bed boilers lies in the regulation of the circulation flow rate. In order to increase the load regulation rate of circulating fluidized bed boilers, the regulation rate of the circulation flow rate needs to be improved while ensuring the stable and safe operation of the boiler. However, due to its own technical characteristics, the ability of circulating fluidized bed boilers to adapt to rapid load changes is low, and there is a large room for improvement. As an important component of a circulating fluidized bed boiler, the separation efficiency of the cyclone separator directly determines the amount of particles entering the feed leg, that is, determines the size of the circulation flow rate. Therefore, the circulation flow rate can be adjusted within a certain range by adjusting the separation efficiency of the cyclone separator. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a circulating fluidized bed boiler circulation rate adjustment structure, which can adjust the circulation rate of the circulating fluidized bed boiler and has the advantages of easy adjustment, fast response speed and simple operation.

[0005] The regulating structure of the circulating flow rate of a circulating fluidized bed boiler according to an embodiment of the present invention comprises:

[0006] Cyclone separator;

[0007] A ventilation pipe, the ventilation pipe passes through the side wall of the dipleg of the cyclone separator, one end of the ventilation pipe is located at the inner upper end of the dipleg and has a vent, and the other end of the ventilation pipe is located outside the dipleg;

[0008] An air intake and exhaust assembly is connected to the other end of the ventilation pipe, and is used for intake air into the inner upper end of the material leg through the ventilation pipe to increase the pressure at the inner upper end of the material leg, and exhaust air from the inner upper end of the material leg through the ventilation pipe to reduce the pressure at the inner upper end of the material leg.

[0009] The regulating structure of the circulating fluidized bed boiler circulation rate according to the embodiment of the present invention has the following advantages: first, the circulating fluidized bed boiler circulation rate can be regulated without making complex changes to the overall structure of the circulating fluidized bed boiler, and the normal operation of the furnace and the return system of the circulating fluidized bed boiler will not be disturbed, which is convenient for promotion and application; second, the circulating flow rate can be flexibly adjusted according to the operating load required by the circulating fluidized bed boiler, so that the circulating fluidized bed boiler can cope with operating conditions of different loads; third, the separation efficiency of the cyclone separator can be adjusted by controlling the air intake speed and the exhaust speed of the ventilation pipe, so that the circulating flow rate of the circulating fluidized bed boiler can be quickly adjusted. Therefore, the present invention improves the rate of load change during the operation of the circulating fluidized bed boiler, increases the flexibility of the operation of the circulating fluidized bed boiler, helps the deep peak regulation of the circulating fluidized bed unit, and is suitable for the transformation of newly built units and existing units; fourth, the regulating structure of the circulating fluidized bed boiler circulation rate of the present invention is easy to adjust, simple to operate, has a longer service life, and has little interference with the combustion state in the furnace.

[0010] In some embodiments, the air intake and exhaust components include an air intake bypass and an exhaust bypass; one end of the air intake bypass is connected to the other end of the ventilation pipe, and is used to introduce air into the inner upper end of the material leg; one end of the exhaust bypass is connected to the other end of the ventilation pipe, and is used to exhaust air from the inner upper end of the material leg.

[0011] In some embodiments, the air intake bypass includes an air intake pipe and an air intake fan; one end of the air intake pipe is connected to the other end of the ventilation pipe, and the other end of the air intake pipe is connected to the air intake fan. The air intake bypass also includes an air intake regulating valve, and the air intake regulating valve is arranged on the air intake pipe.

[0012] In some embodiments, the exhaust bypass includes an exhaust pipe and an exhaust fan; one end of the exhaust pipe is connected to the other end of the ventilation pipe, and the other end of the exhaust pipe is connected to the exhaust fan. The exhaust bypass also includes an exhaust regulating valve, which is arranged on the exhaust pipe. The part of the ventilation pipe located outside the material leg and the wall surface of the exhaust pipe are insulating walls or water-cooled walls.

[0013] In some embodiments, one end of the ventilation tube extends coaxially with the dipleg.

[0014] In some embodiments, the vent is facing upward or downward, or the vent is located on a side wall at one end of the ventilation pipe; when the vent is facing upward, a hood is provided above the vent.

[0015] In some embodiments, the vent is provided with a filter.

[0016] In some embodiments, the gap between one end of the ventilation pipe and the material leg is 2 to 5 times the outer diameter of the ventilation pipe.

[0017] In some embodiments, the vent tube includes an expansion joint, which is located outside the dipleg and does not contact the dipleg.

[0018] In some embodiments, the circulating fluidized bed boiler includes one or more cyclone separators, and each cyclone separator is equipped with the ventilation pipe and the air intake and exhaust components.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0021] Figure 1 It is a schematic diagram of the overall structure of the regulating structure of the circulation flow rate of a circulating fluidized bed boiler according to an embodiment of the present invention.

[0022] Figure 2 It is a front view of the regulating structure of the circulating fluidized bed boiler circulation flow rate according to an embodiment of the present invention.

[0023] Figure 3 This is a bottom view of the circulating fluidized bed boiler circulation flow rate adjustment structure of the embodiment of the present invention after removing the lower seat.

[0024] Figure 4 This is a cross-sectional view with the vent facing upward.

[0025] Figure 5 It is a first structural schematic diagram when the ventilation opening is located on a side wall at one end of the ventilation pipe.

[0026] Figure 6 It is a second structural schematic diagram when the ventilation port is located on a side wall at one end of the ventilation pipe.

[0027] Figure 7 Schematic diagram of the structure of the second connecting mechanism in an embodiment of the present invention.

[0028] Reference numerals:

[0029] Circulating fluidized bed boiler circulation rate adjustment structure 1000

[0030] Cyclone separator 1

[0031] Material leg 101 cone section 102 cylinder section 103 exhaust pipe 104 inlet flue 105

[0032] Ventilation pipe 2

[0033] Vertical pipe section 201 Horizontal pipe section 202 Ventilation port 203 Wind cap 2031 Expansion joint 204

[0034] Air intake and exhaust components 3

[0035] Intake bypass 301 Intake pipe 3011 Intake fan 3012 Intake regulating valve 3013

[0036] Air extraction bypass 302 Air extraction pipe 3021 Air extraction machine 3022 Air extraction regulating valve 3023 DETAILED DESCRIPTION

[0037] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0038] Combine the following Figures 1 to 7 The regulating structure 1000 of the circulating fluidized bed boiler circulation flow rate of the present invention is described.

[0039] like Figures 1 to 7 As shown, the structure 1000 for regulating the circulation flow rate of a circulating fluidized bed boiler according to an embodiment of the present invention comprises a cyclone separator 1, a ventilation pipe 2 and an air intake and exhaust assembly 3, the ventilation pipe 2 passes through the side wall of the material leg 101 of the cyclone separator 1, one end of the ventilation pipe 2 is located at the inner upper end of the material leg 101 and has a ventilation port 203, and the other end of the ventilation pipe 2 is located outside the material leg 101; the air intake and exhaust assembly 3 is connected to the other end of the ventilation pipe 2, and is used for intake air into the inner upper end of the material leg 101 through the ventilation pipe 2 to increase the pressure at the inner upper end of the material leg 101, and exhaust air from the inner upper end of the material leg 101 through the ventilation pipe 2 to reduce the pressure at the inner upper end of the material leg 101.

[0040] Specifically, the cyclone separator 1 includes a material leg 101, a tapered section 102, a barrel section 103 and an exhaust pipe 104 which are sequentially connected from bottom to top. The lower end of the exhaust pipe 104 extends into the barrel section 103. An inlet flue 105 is provided on the side wall of the barrel section 103 near the top. The wall surfaces of the tapered section 102 and the barrel section 103 may be insulated wall surfaces, water-cooled wall surfaces or steam-cooled wall surfaces to reduce heat loss.

[0041] The ventilation pipe 2 passes through the side wall of the dipleg 101 of the cyclone separator 1 , one end of the ventilation pipe 2 is located at the inner upper end of the dipleg 101 and has a ventilation opening 203 , and the other end of the ventilation pipe 2 is located outside the dipleg 101 . One end of the ventilation pipe 2 is located at the inner upper end of the material leg 101, that is, one end of the ventilation pipe 2 is close to the lower outlet of the conical section 102. It should be noted that the part of the ventilation pipe 2 located inside the material leg 101 includes a vertical pipe section 201 and a horizontal pipe section 202. The vertical pipe section 201 extends in the up and down direction. The vent 203 is arranged on the vertical pipe section 201. The lower end of the vertical pipe section 201 is fixedly connected to one end of the horizontal pipe section 202. The horizontal pipe section 202 is fixed on the material leg 101. In this way, when the ventilation pipe 2 is taking in air or the ventilation pipe 2 is exhausting air, the airflow direction near one end of the ventilation pipe 2 is or is approximately vertical, so that the airflow near one end of the ventilation pipe 2 will not be turbulent or the turbulence is very small, which is beneficial to prolonging the service life of the ventilation pipe 2 and the cyclone separator 1.

[0042] The air intake and exhaust assembly 3 is connected to the other end of the ventilation pipe 2, and is used to intake air into the inner upper end of the material leg 101 through the ventilation pipe 2 to increase the pressure at the inner upper end of the material leg 101, that is, to increase the pressure near the lower outlet of the conical section 102, thereby causing the air flow field at the bottom of the conical section 102 to become turbulent, thereby achieving the purpose of reducing the separation efficiency of the cyclone separator 1. At this time, the amount of fly ash escaping from the exhaust pipe 104 increases.

[0043] Air is extracted from the inner upper end of the material leg 101 through the ventilation pipe 2 to reduce the pressure at the inner upper end of the material leg 101, that is, to reduce the pressure near the lower outlet of the conical section 102, so that the air flow field at the bottom of the conical section 102 is more orderly, thereby improving the separation efficiency of the cyclone separator 1. At this time, the amount of fly ash escaping from the exhaust pipe 104 is reduced.

[0044] In summary, according to the circulating fluidized bed boiler circulation flow rate adjustment structure 1000 of the embodiment of the present invention, a ventilation pipe 2 having one end located at the inner upper end of the material leg 101 and having a ventilation port 203 is provided, and an air intake and exhaust assembly 3 is provided outside the material leg 101 and connected to the other end of the ventilation pipe 2. Thus, the air flow field at the bottom of the conical section 102 can be changed by intake air into the inner upper end of the material leg 101 and exhaust air from the inner upper end of the material leg 101, so that the separation efficiency of the cyclone separator 1 is changed, thereby realizing the adjustment of the circulation flow rate of the circulating fluidized bed boiler.

[0045] The circulating fluidized bed boiler circulation rate regulating structure 1000 according to the embodiment of the present invention has the following advantages: first, the circulating fluidized bed boiler circulation rate can be regulated without making complex changes to the overall structure of the circulating fluidized bed boiler, and the normal operation of the furnace and the return system of the circulating fluidized bed boiler will not be disturbed, which is convenient for promotion and application; second, the circulating flow rate can be flexibly adjusted according to the operating load required by the circulating fluidized bed boiler, so that the circulating fluidized bed boiler can cope with operating conditions of different loads; third, the separation efficiency of the cyclone separator 1 can be adjusted by controlling the air intake speed and the exhaust speed of the ventilation pipe 2, so that the circulation flow rate of the circulating fluidized bed boiler can be quickly regulated. Therefore, the present invention improves the rate of load change during the operation of the circulating fluidized bed boiler, increases the flexibility of the operation of the circulating fluidized bed boiler, helps the deep peak regulation of the circulating fluidized bed unit, and is suitable for the transformation of new units and existing units; fourth, the circulating fluidized bed boiler circulation rate regulating structure 1000 of the present invention is easy to adjust, simple to operate, has a longer service life, and has little interference with the combustion state in the furnace.

[0046] In some embodiments, Figure 1 and Figure 2 As shown, the air intake and exhaust assembly 3 includes an air intake bypass 301 and an exhaust bypass 302; one end of the air intake bypass 301 is connected to the other end of the ventilation pipe 2, and is used to introduce air into the inner upper end of the material leg 101; one end of the exhaust bypass 302 is connected to the other end of the ventilation pipe 2, and is used to exhaust air from the inner upper end of the material leg 101. That is to say, the air intake bypass 301 and the air extraction bypass 302 are independently separated. When it is necessary to reduce the load of the circulating fluidized bed boiler and the circulation flow rate of the circulating fluidized bed boiler, the air intake bypass 301 can be opened, the air intake rate of the air intake bypass 301 can be increased, and the air extraction bypass 302 can be closed at the same time, thereby increasing the pressure near the lower outlet of the conical section 102, thereby reducing the separation efficiency of the cyclone separator 1; when it is necessary to increase the load of the circulating fluidized bed boiler and the circulation flow rate of the circulating fluidized bed boiler, the air extraction bypass 302 can be opened, the air intake rate of the air extraction bypass 302 can be increased, and the air intake bypass 301 can be closed at the same time, thereby reducing the pressure near the lower outlet of the conical section 102, thereby increasing the separation efficiency of the cyclone separator 1. The use of independently separated air intake bypass 301 and air extraction bypass 302 can make the response speed of air intake and air extraction control faster, which is conducive to improving the regulation rate of the circulation flow rate.

[0047] In some embodiments, the air intake bypass 301 includes an air intake pipe 3011 and an air intake fan 3012; one end of the air intake pipe 3011 is connected to the other end of the ventilation pipe 2, and the other end of the air intake pipe 3011 is connected to the air intake fan 3012, so that the start and stop of air intake can be controlled by controlling the opening and closing of the air intake fan 3012, and the size of air intake can be adjusted by controlling the frequency of the air intake fan 3012. Specifically, the air intake fan 3012 can be an induced draft fan, and the induced draft fan here can be an induced draft fan in an existing circulating fluidized bed boiler, so that the implementation cost of the present invention can be reduced, which is conducive to the popularization and implementation of the present invention.

[0048] In some embodiments, the air intake bypass 301 further includes an air intake regulating valve 3013, which is disposed on the air intake pipe 3011. It is understood that the air intake rate of the air intake bypass 301 can be adjusted by adjusting the opening of the air intake regulating valve 3013. When the opening of the air intake regulating valve 3013 is increased, the pressure increase near the lower outlet of the conical section 102 increases, thereby greatly reducing the separation efficiency of the cyclone separator 1, and thus the circulation flow rate of the circulating fluidized bed boiler can be adjusted within a certain range to cope with operating conditions of different loads.

[0049] In some embodiments, the exhaust bypass 302 includes an exhaust pipe 3021 and an exhaust fan 3022; one end of the exhaust pipe 3021 is connected to the other end of the ventilation pipe 2, and the other end of the exhaust pipe 3021 is connected to the exhaust fan 3022, so that the start and stop of exhaust can be controlled by controlling the opening and closing of the exhaust fan 3022, and the exhaust rate can be adjusted by controlling the frequency of the exhaust fan 3022. Specifically, the exhaust fan 3022 can be a Roots blower, and the Roots blower here can be a Roots blower in an existing circulating fluidized bed boiler, so that the implementation cost of the present invention can be reduced, which is conducive to the popularization and implementation of the present invention.

[0050] In some embodiments, the exhaust bypass 302 further includes an exhaust regulating valve 3023, which is disposed on the exhaust pipe 3021. It is understandable that the exhaust rate of the exhaust bypass 302 can be adjusted by adjusting the opening of the exhaust regulating valve 3023. When the opening of the exhaust regulating valve 3023 is increased, the pressure reduction near the lower outlet of the conical section 102 increases, and the separation efficiency of the cyclone separator 1 is greatly improved, thereby achieving the adjustment of the circulation flow rate of the circulating fluidized bed boiler within a certain range to cope with operating conditions of different loads.

[0051] In some embodiments, the portion of the ventilation pipe 2 outside the material leg 101 and the wall surface of the exhaust pipe 3021 are insulated walls or water-cooled walls. This is because the temperature inside the cyclone separator 1 is very high, and the ventilation pipe 2 is generally a metal pipe with good thermal conductivity. Therefore, the temperature of the portion of the ventilation pipe 2 outside the material leg 101 is usually very high. Setting the portion of the ventilation pipe 2 outside the material leg 101 as an insulated wall surface or a water-cooled wall surface can reduce heat loss and ensure on-site safety; when exhausting air from the cyclone separator 1, the high-temperature gas in the cyclone separator 1 will be discharged through the exhaust pipe 3021, so the temperature of the exhaust pipe 3021 will also be very high, so setting the wall surface of the exhaust pipe 3021 as an insulated wall surface or a water-cooled wall surface can reduce heat loss and ensure on-site safety.

[0052] In some embodiments, one end of the ventilation pipe 2 extends coaxially with the material leg 101. That is, the extension direction of the material leg 101 is the up-down direction, so the extension direction of one end of the ventilation pipe 2 is also the up-down direction, that is, the extension direction of the vertical pipe section 201 of the ventilation pipe 2 is the up-down direction, so that when air is introduced into the vicinity of the lower outlet of the conical section 102 through the ventilation pipe 2 or air is extracted from the vicinity of the lower outlet of the conical section 102, the air flow near one end of the ventilation pipe 2 can be orderly without turbulence or the degree of turbulence is very low, which is conducive to improving the service life of the ventilation pipe 2 and the cyclone separator 1. In addition, the vertical pipe section 201 of the ventilation pipe 2 is coaxially arranged with the material leg 101, so that the vertical pipe section 201 of the ventilation pipe 2 can avoid the high-concentration particle area near the inner wall surface of the material leg 101 as much as possible, reduce wear, and improve the service life of the ventilation pipe 2.

[0053] In some embodiments, the vent 203 faces upward (eg, Figure 1 , Figure 3 , Figure 4 and Figure 7 ) or downward (as shown Figure 2 As shown), or the vent 203 is located on the side wall of one end of the ventilation pipe 2 (as shown Figure 5 and Figure 6 As shown). That is to say, one end of the vertical pipe section 201 of the ventilation pipe 2 is designed to be open, and the opening is upward or downward, or the vent 203 is located on the side wall of the vertical pipe section 201. It can be understood that when the vent 203 is set on the side wall of the vertical pipe section 201, one vent 203 or multiple vents 203 can be set on the side wall of the vertical pipe section 201. When the vent 203 is set on the side wall of the vertical pipe section 201, the diameter of the vent 203 can be set smaller, so that the airflow near one end of the ventilation pipe 2 will not be greatly impacted during air intake or air extraction, so that the airflow near one end of the ventilation pipe 2 will not be disturbed in a large area, thereby ensuring the service life of the ventilation pipe 2 and the cyclone separator 1. When the vent 203 is located on the side wall of the vertical pipe section 201, one end of the ventilation pipe 2 is closed.

[0054] In some embodiments, when the vent 203 faces upward, a hood 2031 is disposed above the vent 203. As shown in FIG7, the hood 2031 is disposed on the upward vent 203, thereby preventing particles from falling directly into the ventilation pipe 2 and blocking the ventilation pipe 2.

[0055] In some embodiments, the vent 203 is provided with a filter (not shown in the figure). It is understandable that the filter can filter the gas entering the ventilation pipe 2, and can prevent larger particles from entering the ventilation pipe 2, thereby preventing the particles from blocking the ventilation pipe 2.

[0056] In some embodiments, the gap between one end of the ventilation pipe 2 and the material leg 101 is 2 to 5 times the outer diameter of the ventilation pipe 2, that is, the gap between one end of the ventilation pipe 2 and the material leg 101 can be 2 times, 3 times, 4 times, 5 times, etc., the outer diameter of the ventilation pipe 2, so that the ventilation pipe 2 can avoid the high-concentration particle area near the inner wall of the material leg 101, reduce the wear of the ventilation pipe 2, and extend the service life of the ventilation pipe 2.

[0057] In some embodiments, Figure 3 As shown, the ventilation pipe 2 includes an expansion joint 204, which is located outside the material leg 101 and does not contact the material leg 101. It can be understood that the arrangement of the expansion joint 204 allows the ventilation pipe 2 to adapt to the deformation caused by the thermal expansion and contraction of the ventilation pipe 2 and the cyclone separator 1, thereby avoiding deformation and damage of the ventilation pipe 2. It can be understood that the expansion joint 204 is arranged on the part of the transverse pipe section 202 located outside the material leg 101.

[0058] In some embodiments, the ventilation pipe 2 is a heat-resistant stainless steel pipe with a wall thickness of 8-20 mm and a maximum tolerable temperature of 1050° C., thereby ensuring the normal use of the ventilation pipe 2 .

[0059] In some embodiments, the circulating fluidized bed boiler includes one or more cyclone separators 1, each cyclone separator 1 is equipped with a ventilation pipe 2 and an air intake and exhaust assembly 3. When the circulating fluidized bed boiler includes multiple cyclone separators 1, the air intake and exhaust assemblies 3 of multiple cyclone separators 1 can be adjusted simultaneously, so that the circulation flow rate of the circulating fluidized bed boiler can be adjusted within a larger range. The multiple cyclone separators 1 are connected in parallel.

[0060] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0061] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A circulating fluidized bed boiler circulation rate adjustment structure, characterized in that: include: Cyclone separators; A ventilation pipe, the ventilation pipe passes through the side wall of the dipleg of the cyclone separator, one end of the ventilation pipe is located at the inner upper end of the dipleg and has a vent, and the other end of the ventilation pipe is located outside the dipleg; an air intake and exhaust assembly connected to the other end of the ventilation pipe, and used for intake air into the inner upper end of the material leg through the ventilation pipe to increase the pressure at the inner upper end of the material leg, and exhaust air from the inner upper end of the material leg through the ventilation pipe to reduce the pressure at the inner upper end of the material leg; The air intake and air extraction components include an air intake bypass and an air extraction bypass; one end of the air intake bypass is connected to the other end of the ventilation pipe, and is used to introduce air into the inner upper end of the material leg; one end of the air extraction bypass is connected to the other end of the ventilation pipe, and is used to extract air from the inner upper end of the material leg; One end of the ventilation pipe extends coaxially with the material leg.

2. The circulating fluidized bed boiler circulation rate adjustment structure according to claim 1, characterized in that: The air intake bypass includes an air intake pipe and an air intake fan; one end of the air intake pipe is connected to the other end of the ventilation pipe, and the other end of the air intake pipe is connected to the air intake fan. The air intake bypass also includes an air intake regulating valve, which is arranged on the air intake pipe.

3. The circulating fluidized bed boiler circulation rate adjustment structure according to claim 2, characterized in that: The exhaust bypass includes an exhaust pipe and an exhaust fan; one end of the exhaust pipe is connected to the other end of the ventilation pipe, and the other end of the exhaust pipe is connected to the exhaust fan. The exhaust bypass also includes an exhaust regulating valve, which is arranged on the exhaust pipe. The part of the ventilation pipe located outside the material leg and the wall surface of the exhaust pipe are insulated walls or water-cooled walls.

4. The circulating fluidized bed boiler circulation rate adjustment structure according to claim 1, characterized in that: The vent is facing upward or downward, or the vent is located on a side wall at one end of the ventilation pipe; when the vent is facing upward, a hood is arranged above the vent.

5. The circulating fluidized bed boiler circulation rate adjustment structure according to claim 4, characterized in that: The vent is provided with a filter.

6. The circulating fluidized bed boiler circulation rate adjustment structure according to claim 1, characterized in that: The gap between one end of the ventilation pipe and the material leg is 2 to 5 times the outer diameter of the ventilation pipe.

7. The circulating fluidized bed boiler circulation rate adjustment structure according to any one of claims 1 to 3, characterized in that: The ventilation pipe includes an expansion joint, which is located outside the dipleg and does not contact the dipleg.

8. The circulating fluidized bed boiler circulation rate adjustment structure according to any one of claims 1 to 3, characterized in that: The circulating fluidized bed boiler comprises one or more cyclone separators, and each cyclone separator is equipped with the ventilation pipe and the air intake and exhaust components.

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