CFB (circulating fluidized bed) boiler and wide-load adjusting type flue gas separator thereof

Abstract

The invention relates to a CFB (Circulating Fluidized Bed) boiler and a wide-load adjusting type flue gas separator thereof in the technical field of boilers. The CFB boiler comprises a flue and a central cylinder, a smoke inlet is formed in the side face of the flue, a smoke outlet is formed in the top end of the flue, a smoke outlet is formed in the bottom end of the flue, and the center cylinder is located in the flue. The center cylinder is provided with gas guide holes, the gas guide holes are located above the gas inlet, the center cylinder is detachably connected with a cover plate, the cover plate covers the gas guide holes, the communicating number of the gas guide holes is adjusted through the cover plate, high-temperature flue gas entering the flue enters the center cylinder from the gas guide holes, the stroke of the high-temperature flue gas can be shortened, and then the gas-solid separation efficiency of the high-temperature flue gas is adjusted. The gas guide holes are opened by disassembling part of or all the cover plates, part of smoke is short-circuited, the length of the center cylinder is shortened in a disguised mode, the working condition requirement for low smoke and dust separation efficiency during low-load operation of a boiler is effectively met, and the load adjusting range of the smoke separator suitable for the boiler operation working condition is widened.

Description

Technical Field

[0001] The present invention relates to the technical field of CFB circulating fluidized bed boilers, and specifically, to a CFB circulating fluidized bed boiler and a wide-load regulating type flue gas separator thereof. Background Art

[0002] The boiler cyclone separator is one of the important components of the CFB circulating fluidized bed boiler, and the central cylinder is the core component installed on the cyclone separator. The size and length of the central cylinder are closely related to the performance of the separator. When the diameter of the central cylinder is reduced, the separation efficiency is improved; when the length of the central cylinder is increased, the separation efficiency is increased.

[0003] In reality, after the design, manufacture, and installation of the boiler are completed, the size and length of the central cylinder of the cyclone separator are determined. However, during the actual operation of the boiler, changes in the fuel composition, particle size distribution, or long-term load requirements of the boiler cause the operating conditions of the central cylinder to often deviate from the design values, which may result in a decrease in separation efficiency, a decrease in the ash concentration in the circulating loop, an increase in the carbon content of the fly ash in the boiler, and an accelerated wear of the heating surface in the tail flue; it may also cause too high separation efficiency, an increase in the ash concentration in the circulating loop, affect the furnace temperature, aggravate the furnace wear, and the resistance of the separator is too large, affecting the boiler load, seriously affecting the safe and economic operation of the boiler equipment.

[0004] Currently, after encountering the above problems during the use stage, due to the structural factors of the boiler cyclone separator itself, local adjustment cannot be carried out, and the overall technical transformation and replacement must be carried out, which has great construction difficulty, large workload, long cycle, and high cost. For example, the patent publication number CN202581291U discloses a central cylinder of a cyclone separator for a circulating fluidized bed boiler, including a cylinder tile, a fixed support, and a reinforcing rib plate. The tile is made of wear-resistant, high-temperature-resistant, and corrosion-resistant cast steel material. The central cylinder is evenly divided into several tiles along the circumferential direction (the number of slices is determined according to the size of the cylinder), and the tiles are welded together. In the length direction of the central cylinder, the originally long cylinder body is divided into several sections, and the sections are connected to each other by hooks. The technical concept of this technology still lies in changing the separation efficiency by changing the length of the central cylinder or the diameter change at the lower end, and there are still the above-related problems. Summary of the Invention

[0005] Aiming at the defects in the prior art, the purpose of the present invention is to provide a CFB circulating fluidized bed boiler and a wide-load regulating type flue gas separator thereof.

[0006] According to a wide-load regulating type flue gas separator provided by the present invention, it includes a flue and a central cylinder; The side of the flue is provided with a flue gas inlet, the top of the flue is provided with a flue gas outlet, the bottom of the flue is provided with a dust outlet, the central cylinder is located inside the flue, the air inlet of the central cylinder is located below the flue gas inlet, the air outlet of the central cylinder is communicated with the flue gas outlet, high-temperature flue gas enters the flue from the flue gas inlet, the dust particles in the high-temperature flue gas fall and are discharged through the dust outlet, and the separated high-temperature flue gas is discharged successively through the air inlet, the air outlet and the flue gas outlet; The central cylinder is provided with air guide holes, the air guide holes are located above the air inlet, and a plurality of the air guide holes are arranged circumferentially on the central cylinder. The central cylinder is detachably connected with a cover plate, and the cover plate covers outside the air guide holes. By adjusting the number of the air guide holes in communication through the cover plate, the high-temperature flue gas entering the flue enters the central cylinder from the air guide holes, which can shorten the travel of the high-temperature flue gas, and further adjust the gas-solid separation efficiency of the high-temperature flue gas.

[0007] In some embodiments, the positions of the air guide holes are correspondingly arranged with the position of the flue gas inlet, and the air guide holes are located between the extended surfaces of the upper and lower end faces of the flue gas inlet.

[0008] In some embodiments, the air guide holes are arranged in layers on the central cylinder, and at least one layer of the air guide holes is arranged on the central cylinder.

[0009] In some embodiments, the arrangement density of the air guide holes on the side of the central cylinder close to the flue gas inlet is greater than the arrangement density of the air guide holes on the side far from the flue gas inlet.

[0010] In some embodiments, the air guide holes are one or more combinations of rectangular holes, circular holes or oval holes.

[0011] In some embodiments, the central cylinder includes an upper cylinder body and a lower cylinder body, the upper cylinder body is detachably connected with the lower cylinder body, and the air guide holes are located on the upper cylinder body.

[0012] In some embodiments, the lower cylinder body is a frustum-shaped structure.

[0013] In some embodiments, the lower cylinder body is formed by enclosing a plurality of parts.

[0014] In some embodiments, the number N of the parts ≥ 3.

[0015] The present invention also provides a CFB circulating fluidized bed boiler, including the wide-load regulation type flue gas separator described above.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The wide-load adjustable flue gas separator of the present invention is provided with air guiding holes on the central cylinder and is equipped with detachable covers for blocking the air guiding holes. By removing some or all of the covers, the air guiding holes are opened, short-circuiting part of the flue gas, effectively shortening the length of the central cylinder, effectively meeting the working conditions requirements of low dust separation efficiency during the low-load operation of the boiler, broadening the lower limit of the applicable boiler operating conditions of the flue gas separator, effectively reducing the equipment cost, and being simple and convenient to operate and maintain, improving the production efficiency.

[0017] 2. The wide-load adjustable flue gas separator of the present invention optimizes the design of the central cylinder into a split structure. Through the split structure, the lower cylinder with different lengths and / or different diameters can be applied according to the working conditions, further broadening the load adjustment range of the flue gas separator applicable to the boiler operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] By reading the detailed description of the non-restrictive embodiments with reference to the following drawings, other features, objectives, and advantages of the present invention will become more apparent: Figure 1 is a structural cross-sectional view of the wide-load adjustable flue gas separator of the present invention; Figure 2 is a schematic structural view of the central cylinder of the wide-load adjustable flue gas separator of the present invention; Figure 3 is a schematic structural view of the central cylinder of the wide-load adjustable flue gas separator of the present invention provided with multiple layers of air guiding holes; Figure 4 is a schematic cross-sectional view of the split structure of the wide-load adjustable flue gas separator of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several changes and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention. Embodiment

[0020] This embodiment provides an adjustable cyclone separator, as Figures 1-4 shown, mainly including a flue 100 and a central cylinder 200 installed in the flue 100. As Figure 1As shown in the figure, the flue 100 is vertically arranged. A flue gas inlet 110 is provided on the side of the upper-middle part of the flue 100. High-temperature flue gas enters the cavity of the flue 100 from the flue gas inlet 110. A flue gas outlet 120 is provided at the upper end of the flue 100, which is used to discharge the high-temperature flue gas after gas-solid separation into the next heat exchange link. And the lower end of the flue is a dust outlet 130. The dust particles separated by gravity and centrifugal force are gathered at the dust outlet 130 and discharged.

[0021] The central cylinder 200 installed in the flue 100 is a columnar cylinder structure as a whole, as Figures 1-2 shown. The central cylinder 200 is fixedly connected to the isolation plate 140 at the upper end of the flue 100 by a clamping method. The upper and lower ends of the central cylinder 200 are an air outlet 220 and an air inlet 210 respectively. The air inlet 210 is located below the isolation plate 140, and the horizontal plane of the air inlet 210 is not higher than the horizontal plane where the lower end of the flue gas inlet 110 is located. And the air outlet 220 is located above the isolation plate 140. There are a plurality of air guide holes 230 provided on the circumferential surface of the central cylinder 200. The number of air guide holes 230 is multiple, and the air guide holes 230 are located on the central cylinder 200 between the air inlet 210 and the isolation plate 140. In this embodiment, the multiple air guide holes 230 are arranged at intervals in a circle on the circumferential surface of the central cylinder 200 to form an annular structure. The shape of the air guide holes 230 can be a round hole shape, an oval hole shape or a rectangular hole shape. The so-called shape of the air guide holes 230 here refers to the shape after orthographic projection. The air guide holes 230 provided on the cylinder body of the central cylinder 200 are arranged in layers. Each layer of air guide holes 230 refers to a plurality of air guide holes 230 arranged at intervals around the central cylinder 200 in a circle. The number of layers of the air guide holes 230 provided on the central cylinder 200 is at least 1 layer. In some embodiments, the number of layers can be 3 layers or more, as Figure 3 shown. The shape of the air guide holes 230 provided on the central cylinder 200 can be a single shape, such as all being rectangular hole structures, or a combination of multiple shapes. For example, rectangular holes and oval holes are arranged at intervals. The present invention does not limit this. At the same time, a cover plate 240 is covered and connected to the air guide holes 230. Each air guide hole 230 corresponds to a cover plate 240, and the air guide holes 230 are blocked through the cover plate 240. The cover plate 240 is detachably connected to the cylinder body of the central cylinder 200. Its connection method can be through the bolt-screw hole method. By connecting the bolt through the through hole or screw hole opened on the cover plate 240 with the screw hole provided on the cylinder body of the central cylinder 200, the cover plate 240 is detachably connected to the central cylinder 200 to realize the blocking of the air guide holes 230. Appropriately, the shape of the cover plate 240 is an arc-shaped plate, which is more adapted to the circular outer peripheral surface of the central cylinder 200 to ensure the blocking effect.

[0022] The working principle of the adjustable cyclone separator provided in this embodiment is explained as follows: when full-load operation is required to ensure the separation efficiency of smoke and dust, the air guide holes 230 arranged in a circle on the circumference of the central tube 200 are all blocked by the cover plate 240, and the high-temperature smoke enters the cavity of the flue 100 from the smoke inlet 110. Due to the obstruction of the partition 140, the high-temperature smoke moves downward in the direction of the smoke outlet 130. When the high-temperature smoke moves downward for a distance to the air inlet 210, the high-temperature smoke enters the air inlet 210 and moves upward. In the process of the high-temperature smoke moving upward, the dust particles in the smoke are separated from the smoke under the action of gravity and centrifugal force, and the concentration of the separated dust particles is relatively high. The flue gas is discharged from the smoke outlet 130, while the smoke with a smaller solubility of separated dust particles enters the smoke outlet 120 connected thereto from the air outlet 220 and is discharged; when it is necessary to reduce the load, that is, to reduce the smoke separation efficiency, the cover 240 covering part or all of the air guide holes 230 is removed according to predetermined parameters. At this time, when the high-temperature smoke is moving downward toward the smoke outlet 130, since the position of the air guide holes 230 is higher than the air inlet 210, part of the high-temperature smoke directly enters the cavity of the central tube 200 through the air guide holes 230, thereby achieving the effect of short-circuiting part of the smoke, thereby shortening the length of the central tube 200 in disguise and achieving the purpose of reducing the smoke separation efficiency. In this embodiment, air guide holes are opened on the central tube, and a detachable cover plate is used to seal the air guide holes. The air guide holes are opened by removing part or all of the cover plates, thereby short-circuiting part of the flue gas. This shortens the length of the central tube in disguise, effectively meeting the operating conditions of low smoke separation efficiency when the boiler is running at low load, and broadening the lower limit of the flue gas separator applicable to the boiler operating conditions, effectively reducing equipment costs, and simplifying and maintaining operations, thereby improving production efficiency.

[0023] In some embodiments, the position of the air guide holes 230 arranged in an annular shape on the central tube 200 is located in the position corresponding to the smoke inlet 210, that is, the position of the air guide holes 230 is located between the upper and lower end surfaces of the smoke inlet 210. This structural design allows the high-temperature smoke entering from the smoke inlet 210 to enter the central tube 200 through the air guide holes 230 more quickly, thereby increasing the rate of reducing the smoke separation efficiency at low load. Furthermore, the arrangement density of the air guide holes 230 located on the side facing the smoke inlet 210 is greater than the arrangement density of the air guide holes 230 on the side away from the smoke inlet 210, which not only facilitates the high-temperature smoke to quickly enter the central tube 200, but also reduces the amount of smoke that enters the central tube 200 laterally and is discharged through the air guide holes 230 on the other side when the cover plate 240 is fully opened, thereby ensuring that the smoke separation requirements at low load are met. Example

[0024] This Embodiment 2 is formed on the basis of Embodiment 1. By optimizing the design of the central cylinder into a split structure, the split structure can adapt to lower cylinders with different lengths and / or different diameters according to working conditions, further broadening the load adjustment range applicable to the boiler operation conditions of the flue gas separator. Specifically: As Figures 2-4 shown, the upper cylinder 201 and the lower cylinder 202 are connected and fixed by bolts in a socketing manner. In this embodiment, the upper end of the lower cylinder 202 is socketed to the lower end of the upper cylinder 201, and the bolts connecting them share the same set of bolts as those connecting the cover plate 240 and the central cylinder 200, which can reduce costs and physical damage to the central cylinder 200. The air guide hole 230 is located on the upper cylinder 201. In this implementation, the conductor hole 230 is close to the connection part of the upper cylinder 201 and the lower cylinder 202. By designing the central cylinder 200 as a detachable upper cylinder 201 and lower cylinder 202, by replacing the lower cylinder with different lengths and / or diameters, the requirements for the dust separation efficiency under different working conditions can be effectively met. For example, when it is necessary to improve the dust separation efficiency, the lower cylinder 202 with a longer length and / or a smaller diameter can be replaced, and when it is necessary to reduce the dust separation efficiency and opening the air guide hole 230 cannot meet the working condition requirements, the lower cylinder 202 with a shorter length and / or a larger diameter can be further replaced.

[0025] Furthermore, the lower cylinder 202 is a split structure. As Figure 4 shown, it is formed by enclosing multiple tiles 2020. As Figure 3 shown, in this embodiment, the lower cylinder 202 in a frustum shape is formed by welding six split parts 2020. By designing the lower cylinder 202 as a split structure, the maintenance of the lower cylinder 202 can be facilitated. Only a small maintenance window needs to be set in the separator device. Compared with the operation method of the integral structure that requires windowing the equipment body to repair the lower cylinder 202, the maintenance cost can be reduced.

[0026] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application.

[0027] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined arbitrarily with each other.

Claims

1. A wide load regulation type flue gas separator, characterized in that It includes a flue (100) and a central cylinder (200); A flue gas inlet (110) is provided on the side of the flue (100), a flue gas outlet (120) is provided at the top of the flue (100), and a soot outlet (130) is provided at the bottom of the flue (100). The central cylinder (200) is located inside the flue (100). The air inlet (210) of the central cylinder (200) is located below the flue gas inlet (110). The air outlet (220) of the central cylinder (200) is communicated with the flue gas outlet (120). High-temperature flue gas enters the flue (100) from the flue gas inlet (110). The dust particles in the high-temperature flue gas fall and are discharged through the soot outlet (130). The separated high-temperature flue gas is discharged in sequence through the air inlet (210), the air outlet (220), and the flue gas outlet (120); Air guiding holes (230) are provided on the central cylinder (200). The air guiding holes (230) are located above the air inlet (210). A plurality of the air guiding holes (230) are arranged circumferentially on the central cylinder (200). The central cylinder (230) is detachably connected with a cover plate (240). The cover plate (240) covers outside the air guiding holes (230). The number of the air guiding holes (230) in communication is adjusted through the cover plate (240). The high-temperature flue gas entering the flue (100) enters the central cylinder (200) from the air guiding holes (230), which can shorten the travel of the high-temperature flue gas, and thus adjust the gas-solid separation efficiency of the high-temperature flue gas.

2. The wide-load regulation type flue gas separator according to claim 1, characterized in that, The positions of the air guiding holes (230) are correspondingly arranged with those of the flue gas inlet (110). The air guiding holes (230) are located between the extended surfaces of the upper and lower end faces of the flue gas inlet (110).

3. The wide-load regulation type flue gas separator according to claim 2, characterized in that, The air guiding holes (230) are arranged in layers on the central cylinder (200). At least one layer of the air guiding holes (230) is provided on the central cylinder (200).

4. The wide-load-adjustable flue gas separator according to claim 3, characterized in that, The arrangement density of the air guiding holes (230) on the side of the central cylinder (200) close to the flue gas inlet (110) is greater than that of the air guiding holes (230) on the side far from the flue gas inlet (110).

5. The wide-load regulation type flue gas separator according to claim 1, characterized in that, The air guiding holes (230) are one or a combination of rectangular holes, circular holes, or elliptical holes.

6. The wide-load adjustment type flue gas separator according to any one of claims 1-5, characterized in that, The central cylinder (200) includes an upper cylinder body (201) and a lower cylinder body (202). The upper cylinder body (201) is detachably connected with the lower cylinder body (202). The air guiding holes (230) are located on the upper cylinder body (201).

7. The wide-load regulation type flue gas separator according to claim 6, characterized in that The lower cylinder body (202) is of a frustum-shaped structure.

8. The wide load adjustment type flue gas separator according to claim 7, characterized in that The lower cylinder body (202) is formed by enclosing a plurality of parts (2020).

9. The wide load adjustment type flue gas separator according to claim 8, characterized in that The number N of the parts (2020) is ≥3.

10. A CFB circulating fluidized bed boiler, characterized in that, It includes a wide-load-adjustable flue gas separator according to any one of claims 1-9.

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