Cyclone with variable cross-section inlet flue and circulating fluidized bed boiler

Abstract

The application discloses a cyclone separator with a variable cross-section inlet flue and a circulating fluidized bed boiler, and relates to the technical field of the circulating fluidized bed boiler, in particular to the cyclone separator with the variable cross-section inlet flue for the circulating fluidized bed boiler.The cyclone separator with the variable cross-section inlet flue for the circulating fluidized bed boiler comprises a cylindrical barrel, a conical section connected with the cylindrical barrel and located below the cylindrical barrel, an exhaust pipe arranged on a top wall of the cylindrical barrel, and an inlet flue comprising a top wall, a bottom wall, an outer side wall and an inner side wall, wherein the outer side wall is connected with the top wall and the bottom wall respectively and is tangent to the cylindrical barrel, and the horizontal section of the inner side wall meets a predetermined line shape, the predetermined line shape has a connecting point connected with the cylindrical barrel, an inlet point away from the cylindrical barrel in a direction parallel to the outer side wall, and a minimum cross-section point with the minimum distance to the outer side wall in a direction perpendicular to the outer side wall.The cyclone separator with the variable cross-section inlet flue for the circulating fluidized bed boiler has the advantages of high separation efficiency.

Description

Technical Field

[0001] This invention relates to the field of thermal power generation technology, and more specifically, to a cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue and a circulating fluidized bed boiler having the cyclone separator for a circulating fluidized bed boiler with the variable cross-section inlet flue. Background Technology

[0002] As the proportion of renewable energy generation in the power system gradually increases, thermal power generating units need to play a "ballast" role in the power system to ensure the absorption of renewable energy generation and the safe operation of the power grid.

[0003] In thermal power generation plants, circulating fluidized bed (CFB) boilers offer advantages such as wide fuel adaptability, low pollution control costs, and stable operation under low loads. However, to cope with the power system transformation, CFB boilers need to further leverage their fuel adaptability advantages, deepen the large-scale application of low-cost fuels, further strengthen the control of pollutants, especially nitrogen oxides and sulfur dioxide, in-furnace emissions, and further enhance operational flexibility. The separation efficiency and other performance characteristics of cyclone separators used in CFB boilers play a crucial role in enabling CFB boilers to adapt to the power system transformation.

[0004] Cyclone separators for circulating fluidized bed boilers in related technologies aim to improve the efficiency of cyclone separators by gradually shrinking the cross-sectional area of ​​the inlet section to accelerate the separation of gas and solid particles, but the improvement in separation efficiency is limited. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a cyclone separator for circulating fluidized bed boilers with a variable cross-section inlet flue, which has the advantages of high separation efficiency.

[0006] The present invention also proposes a circulating fluidized bed boiler having a cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue.

[0007] To achieve the above objectives, according to an embodiment of the first aspect of the present invention, a cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue is provided. The cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue includes: a cylindrical body; a conical section connected to the cylindrical body and located below the cylindrical body; an exhaust pipe disposed on the top wall of the cylindrical body; and an inlet flue including a top wall, a bottom wall, an outer side wall, and an inner side wall, the top wall, the bottom wall, the outer side wall, and the inner side wall jointly defining a flow area within the inlet flue. The top wall is flush with the top wall of the cylindrical body, the bottom wall is parallel to the top wall and spaced apart vertically, and the outer side walls are connected to the top wall and the bottom wall respectively and to the cylindrical body. The inner sidewall is tangent to the body, and its horizontal cross-section satisfies a predetermined shape. The predetermined shape is either a broken line or an arc, so that the cross-sectional area of ​​the flow area in the inlet flue, perpendicular to the flue gas inflow direction, gradually decreases and then gradually increases from the inlet of the inlet flue towards the inlet of the cylindrical body. The predetermined shape has a connection point connected to the cylindrical body, an inlet point away from the cylindrical body in the direction parallel to the outer sidewall, and a minimum cross-sectional point with the smallest distance from the outer sidewall in the direction perpendicular to the outer sidewall. The distance between the minimum cross-sectional point and the connection point in the direction perpendicular to the outer sidewall is equal to 2%-5% of the diameter of the cylindrical body, and the distance between the connection point and the connection point in the horizontal direction parallel to the outer sidewall is 5%-25% of the diameter of the cylindrical body.

[0008] The cyclone separator for circulating fluidized bed boilers with a variable cross-section inlet flue according to embodiments of the present invention has the advantages of high separation efficiency.

[0009] In addition, the cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue according to the above embodiments of the present invention may also have the following additional technical features:

[0010] According to one embodiment of the present invention, the distance between the connection point and the outer wall in a direction perpendicular to the outer wall is greater than the distance between the minimum cross-section point and the outer wall and less than the distance between the inlet point and the outer wall, so that the inlet area of ​​the circulation area in the inlet flue is greater than the outlet area of ​​the circulation area in the inlet flue.

[0011] According to one embodiment of the present invention, the distance between the minimum cross-section point and the connection point in a direction perpendicular to the outer side wall is 120-250 mm.

[0012] According to one embodiment of the present invention, the distance between the minimum cross-section point and the connection point in a horizontal direction parallel to the outer side wall is 300-1500 mm.

[0013] According to one embodiment of the present invention, the distance between the minimum cross-section point and the connection point in the direction perpendicular to the outer wall is 200 mm, and the distance between the minimum cross-section point and the connection point in the horizontal direction parallel to the outer wall is 700 mm.

[0014] According to one embodiment of the present invention, the predetermined line shape is a broken line and also has at least one secondary inflection point, the secondary inflection point being farther away from the outer wall from the minimum cross-section point in a direction perpendicular to the outer wall and farther away from the connection point from the minimum cross-section point in a horizontal direction parallel to the outer wall.

[0015] According to one embodiment of the present invention, the upper end of the exhaust pipe is higher than the top wall of the cylindrical body and the lower end extends into the cylindrical body.

[0016] According to one embodiment of the present invention, the diameter of the cylindrical body is 2-10 meters.

[0017] According to an embodiment of a second aspect of the present invention, a circulating fluidized bed boiler is provided, the circulating fluidized bed boiler comprising a cyclone separator for a circulating fluidized bed boiler having a variable cross-section inlet flue as described in an embodiment of a first aspect of the present invention.

[0018] The circulating fluidized bed boiler according to embodiments of the present invention has the advantage of high separation efficiency by utilizing the cyclone separator for circulating fluidized bed boilers with variable cross-section inlet flue as described in the first aspect of the present invention.

[0019] According to one embodiment of the present invention, the cyclone separator for the circulating fluidized bed boiler with variable cross-section inlet flue is of multiple types.

[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0022] Figure 1 This is a schematic diagram of the structure of a cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue according to an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the structure of a cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue, according to a specific embodiment of the present invention.

[0024] Figure 3This is a schematic diagram of the structure of a cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue, according to another specific embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of the structure of a cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue, according to another specific embodiment of the present invention.

[0026] Reference numerals in the attached drawings: Cyclone separator for circulating fluidized bed boilers with variable cross-section inlet flue 1, cylindrical body 11, conical section 12, exhaust pipe 20, inlet flue 30, top wall 31, bottom wall 32, outer side wall 33, inner side wall 34, connection point 41, inlet point 42, minimum cross-section point 43, secondary inflection point 44. Detailed Implementation

[0027] This application is based on the inventor's discoveries and understanding of the following facts and problems:

[0028] Cyclone separators for circulating fluidized bed boilers in related technologies aim to accelerate the separation of gas and solid particles by gradually shrinking the cross-sectional area of ​​the inlet section. However, the improvement in separation efficiency is limited, and the degree of shrinkage is difficult to determine. When the degree of shrinkage is not well selected, the separation efficiency will actually decrease.

[0029] Specifically, in the related technology, the cyclone separator for circulating fluidized bed boilers has a limited improvement in separation efficiency or may even decrease when the cross-sectional area of ​​the inlet section is reduced by a fixed ratio.

[0030] Some cyclone separators use a Venturi structure for the inlet section, which makes the cross-sectional area of ​​the inlet section decrease first and then increase in the direction of gas inflow. However, the Venturi structure itself has a complex effect on airflow, and its design and setting are difficult. The ratio of cross-sectional area change is even more difficult to determine, resulting in limited improvement or even reduction in separation efficiency.

[0031] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0032] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] The following description, with reference to the accompanying drawings, describes a cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue according to an embodiment of the present invention.

[0035] like Figures 1-4 As shown, the cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue according to an embodiment of the present invention includes a cylindrical body 11, a conical section 12, an exhaust pipe 20, and an inlet flue 30.

[0036] The conical section 12 is connected to the cylindrical body 11 and located below the cylindrical body 11. The exhaust pipe 20 is located on the top wall of the cylindrical body 11. The inlet flue 30 includes a top wall 31, a bottom wall 32, an outer wall 33, and an inner wall 34. The top wall 31, bottom wall 32, outer wall 33, and inner wall 34 together define the flow area within the inlet flue. The top wall 31 is flush with the top wall of the cylindrical body 11. The bottom wall 32 is parallel to the top wall 31 and spaced apart vertically. The outer wall 33 is connected to the top wall 31 and the bottom wall 32 respectively and is tangent to the cylindrical body 11. The horizontal cross-section of the inner wall 34 satisfies a predetermined shape, which is a broken line or an arc shape, so that the cross-sectional area of ​​the flow area within the inlet flue in the direction perpendicular to the flue gas inflow is equal to that of the inlet flue 31. The inlet of 0 gradually decreases and then gradually increases in the direction of the inlet of the cylindrical body 11. The predetermined line shape has a connection point 41 connected to the cylindrical body 11, an inlet point 42 away from the cylindrical body 11 in the direction parallel to the outer wall 33, and a minimum cross-section point 43 with the smallest distance from the outer wall 33 in the direction perpendicular to the outer wall 33. The distance between the minimum cross-section point 43 and the outer wall 33 in the direction perpendicular to the outer wall 33 is equal to 2%-5% of the diameter of the cylindrical body 11, and the distance between the minimum cross-section point 43 and the connection point 41 in the horizontal direction parallel to the outer wall 33 is 5%-25% of the diameter of the cylindrical body 11.

[0037] According to an embodiment of the present invention, the cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue can effectively accelerate the airflow after passing through the inlet flue 30 by gradually decreasing and then gradually increasing the cross-sectional area of ​​the flow area in the inlet flue perpendicular to the flue gas inflow direction. This increases the separation efficiency of the cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue. Compared with cyclone separators in related technologies where the cross-sectional area of ​​the flow area in the inlet flue gradually decreases, this method avoids the fixed-proportion contraction of the cross-sectional area of ​​the flow area in the inlet flue, which can more effectively increase the airflow velocity and improve the non-uniformity of particle and gas distribution in the inlet flue 30, thereby improving the separation efficiency and controlling the increase in pressure drop.

[0038] Furthermore, by ensuring that the horizontal cross-section of the inner wall 34 satisfies a predetermined shape, which is either a broken line or an arc, the predetermined shape has a connection point 41 connected to the cylindrical body 11, an inlet point 42 located away from the cylindrical body 11 in a direction parallel to the outer wall 33, and a minimum cross-section point 43 located at the minimum distance from the outer wall 33 in a direction perpendicular to the outer wall 33. The distance 'a' between the minimum cross-section point 43 and the connection point 41 in the direction perpendicular to the outer wall 33 is equal to 2%-5% of the diameter of the cylindrical body 11, and the distance 'a' between the minimum cross-section point 43 and the connection point 41 in the horizontal direction parallel to the outer wall 33 is equal to 2%-5% of the diameter of the cylindrical body 11. The distance b from point 41 is 5%-25% of the diameter of the cylindrical body 11. This not only facilitates the formation of a flow area in the inlet flue with a cross-section that first decreases and then increases, but also ensures the shape of the flow area in the inlet flue by limiting the position of the minimum cross-section point 43. This further enhances the acceleration effect of the flow area in the inlet flue on the airflow, further improves the non-uniformity of particle and gas distribution in the flow area of ​​the inlet flue, and further improves the separation efficiency of the cyclone separator 1 for circulating fluidized bed boilers with variable cross-section inlet flues and controls the increase in pressure drop.

[0039] Furthermore, by including a top wall 31, a bottom wall 32, an outer wall 33, and an inner wall 34 in the inlet flue 30, the shape of the flow area within the inlet flue can be adjusted solely by changing the shape of the predetermined line of the horizontal cross-section of the inner wall 34. Compared to cyclone separators with a Venturi structure in the inlet section in related technologies, this makes the shape of the flow area within the inlet flue more variable, reduces the difficulty of selecting the shape of the flow area within the inlet flue, facilitates the modification of existing cyclone separators, simplifies the design and installation of the inlet flue 30, and makes it easier to determine the shape of the predetermined line to determine the shape of the flow area within the inlet flue, thereby ensuring the improved separation efficiency of the inlet flue 30 and controlling the increase in pressure drop.

[0040] Therefore, the cyclone separator 1 for circulating fluidized bed boilers with a variable cross-section inlet flue according to the present invention has the advantages of high separation efficiency.

[0041] The following description, with reference to the accompanying drawings, describes a cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue, according to a specific embodiment of the present invention.

[0042] In some specific embodiments of the present invention, such as Figures 1-4 As shown, the cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue according to an embodiment of the present invention includes a barrel 10, an exhaust pipe 20, and an inlet flue 30.

[0043] Specifically, such as Figures 2-4As shown, in the direction perpendicular to the outer wall 33, the distance between the connection point 41 and the outer wall 33 is greater than the distance between the minimum cross-section point 43 and the outer wall 33, but less than the distance between the inlet point 42 and the outer wall 33, so that the inlet area of ​​the flow area in the inlet flue is greater than the outlet area of ​​the flow area in the inlet flue. This allows the cross-sectional area of ​​the flow area in the inlet flue to first increase and then decrease along the flue gas inflow direction, resulting in an overall smaller cross-sectional area. This facilitates airflow acceleration, improves the acceleration effect of the inlet flue 30 on the airflow, and controls the increase in pressure drop.

[0044] Optionally, the diameter of the cylindrical body 11 is 2-10 meters, and preferably 6 meters. This allows the cylindrical body 11 to have reasonable dimensions, which facilitates the manufacture of the cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue while ensuring volume.

[0045] Furthermore, the outer wall 33 has a horizontal length of 6 meters. This allows the inlet flue 30 to have reasonable dimensions, facilitating its manufacture while ensuring the acceleration and guidance effect on airflow.

[0046] Advantageously, such as Figures 2-4 As shown, the distance 'a' between the minimum cross-section point 43 and the connection point 41 in the direction perpendicular to the outer wall 33 is 120-300 mm, preferably 120-250 mm. This further defines the position of the minimum cross-section point 43, thereby facilitating the control of the shape of the inner wall 34 to limit the shape of the flow area within the inlet flue, improving the acceleration effect and non-uniformity of the airflow in the inlet flue 30, increasing the separation efficiency of the cyclone separator 1 for circulating fluidized bed boilers with variable cross-section inlet flues, and controlling the increase in pressure drop.

[0047] More advantageously, such as Figures 2-4 As shown, the distance b between the minimum cross-section point 43 and the connection point 41 in the horizontal direction parallel to the outer wall 33 is 300-1500 mm. This further defines the position of the minimum cross-section point 43, thereby further facilitating the control of the shape of the inner wall 34 to limit the shape of the flow area within the inlet flue, improving the acceleration effect and non-uniformity of the airflow in the inlet flue 30, improving the separation efficiency of the cyclone separator 1 for circulating fluidized bed boilers with variable cross-section inlet flues, and controlling the increase in pressure drop.

[0048] In some specific examples, the following is adopted: Figure 2The structure shown has a minimum cross-section point 43 and connection point 41 with a distance a of 200 mm in the direction perpendicular to the outer wall, and a distance b of 700 mm in the horizontal direction parallel to the outer wall 33. A cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue duct 30 (a = 200 mm, b = 700 mm) was verified using numerical simulation. Compared to cyclone separators in related technologies where the inlet section cross-section gradually decreases, the separation efficiency increased by 1.79%, while the pressure drop increase was only 408.71 Pa.

[0049] Those skilled in the art will understand that the above numerical simulations are only used to verify the above values ​​and do not indicate that the above values ​​were obtained through a limited number of experiments.

[0050] Figure 2 A cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue is shown according to some examples of the present invention. For example... Figure 2 As shown, the predetermined line shape of the inner wall 34 is a broken line with a single inflection point and the minimum cross-section point 43 is the inflection point.

[0051] Figure 3 A cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue is shown, according to some other examples of the present invention. For example... Figure 3 As shown, the predetermined line shape is a broken line and also has at least one secondary inflection point 44. The secondary inflection point 44 is farther away from the outer wall 33 than the minimum cross-section point 43 in the direction perpendicular to the outer wall 33 and farther away from the connection point 41 than the minimum cross-section point 43 in the horizontal direction parallel to the outer wall 33. This allows the predetermined line shape to be a broken line with multiple inflection points, with the minimum cross-section point 43 being one of the inflection points, thus allowing for more flexible selection of the shape of the inner wall 34.

[0052] Figure 4 A cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue is shown according to some further examples of the present invention. For example... Figure 4 As shown, the predetermined line shape is an arc shape.

[0053] Specifically, such as Figure 1 As shown, the upper end of the exhaust pipe 20 is higher than the top wall of the cylindrical body 11, and the lower end extends into the cylindrical body 11. This facilitates the installation of the exhaust pipe 20.

[0054] Optionally, the diameter of the cylindrical body 11 is 2-10 meters, and preferably 6 meters. This allows the cylindrical body 11 to have reasonable dimensions, which facilitates the manufacture of the cyclone separator 1 for a circulating fluidized bed boiler with a variable cross-section inlet flue while ensuring volume.

[0055] The following describes a circulating fluidized bed boiler according to an embodiment of the present invention. The circulating fluidized bed boiler according to an embodiment of the present invention includes a cyclone separator 1 for a circulating fluidized bed boiler having a variable cross-section inlet flue according to the above-described embodiment of the present invention.

[0056] The circulating fluidized bed boiler according to the embodiments of the present invention has the advantages of high separation efficiency by utilizing the cyclone separator 1 for circulating fluidized bed boiler with variable cross-section inlet flue according to the above embodiments of the present invention.

[0057] Optionally, there may be one or more cyclone separators 1 for circulating fluidized bed boilers with variable cross-section inlet flues.

[0058] Other configurations and operations of the circulating fluidized bed boiler according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0059] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue, characterized in that, include: Cylindrical tube; A tapered section, which is connected to the cylindrical body and located below the cylindrical body; An exhaust pipe is disposed on the top wall of the cylindrical body; An inlet flue includes a top wall, a bottom wall, an outer wall, and an inner wall. These walls collectively define a flow area within the inlet flue. The top wall is flush with the top wall of the cylindrical body. The bottom wall is parallel to the top wall and spaced apart vertically. The outer walls are connected to both the top and bottom walls and are tangent to the cylindrical body. The horizontal cross-section of the inner wall satisfies a predetermined shape, which is either a broken line or an arc, such that the cross-sectional area of ​​the flow area within the inlet flue perpendicular to the flue gas inflow direction is equal to the cross-sectional area of ​​the inlet flue. The inlet of the flue gradually decreases and then gradually increases in the direction towards the inlet of the cylindrical body. The predetermined line shape has a connection point connected to the cylindrical body, an inlet point away from the cylindrical body in the direction parallel to the outer wall, and a minimum cross-section point with the smallest distance from the outer wall in the direction perpendicular to the outer wall. The distance between the minimum cross-section point and the connection point in the direction perpendicular to the outer wall is equal to 2%-5% of the diameter of the cylindrical body, and the distance between the connection point and the connection point in the horizontal direction parallel to the outer wall is 5%-25% of the diameter of the cylindrical body. In a direction perpendicular to the outer wall, the distance between the connection point and the outer wall is greater than the distance between the minimum cross-section point and the outer wall and less than the distance between the inlet point and the outer wall, so that the inlet area of ​​the circulation area in the inlet flue is greater than the outlet area of ​​the circulation area in the inlet flue.

2. The cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue as described in claim 1, characterized in that, The distance between the minimum cross-section point and the connection point in the direction perpendicular to the outer side wall is 120-250 mm.

3. The cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue as described in claim 1, characterized in that, The distance between the minimum cross-section point and the connection point in the horizontal direction parallel to the outer side wall is 300-1500 mm.

4. The cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue as described in claim 1, characterized in that, The distance between the minimum cross-section point and the connection point in the direction perpendicular to the outer wall is 200 mm, and the distance between the minimum cross-section point and the connection point in the horizontal direction parallel to the outer wall is 700 mm.

5. The cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue according to claim 1, characterized in that, The predetermined line shape is a broken line and also has at least one secondary inflection point, which is farther away from the outer wall from the minimum cross-section point in a direction perpendicular to the outer wall and farther away from the connection point from the minimum cross-section point in a horizontal direction parallel to the outer wall.

6. The cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue according to claim 1, characterized in that, The upper end of the exhaust pipe is higher than the top wall of the cylindrical body, and the lower end extends into the cylindrical body.

7. The cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue according to claim 1, characterized in that, The diameter of the cylindrical body is 2-10 meters.

8. A circulating fluidized bed boiler, characterized in that, Includes a cyclone separator for a circulating fluidized bed boiler with a variable cross-section inlet flue according to any one of claims 1-7.

9. The circulating fluidized bed boiler according to claim 8, characterized in that, The circulating fluidized bed boiler uses multiple cyclone separators with variable cross-section inlet flues.

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