Gas distributor and fluidized bed gasifier

Abstract

The utility model provides a gas distributor and a fluidized bed gasifier. The gas distributor comprises a gas distribution plate and an annular pipe, the gas distribution plate is a conical distribution plate, a narrow opening is formed in the bottom of the conical distribution plate, and a wide opening is formed in the top of the conical distribution plate; the conical distribution plate is provided with a plurality of rows of through holes arranged along the circumferential direction of the conical distribution plate; the central axis extension lines of at least part of the through holes intersect with the axis of the conical distribution plate; the central axis extension lines of at least part of the through holes deviate from the axis of the conical distribution plate to form a first preset angle; and the narrow opening is connected with the ring pipe through a first turning joint. The gas distributor disclosed by the utility model can optimize a gas flowing path and promote the mixing of gas and materials through the venturi tube. And the stress generated by thermal expansion, pressure change or mechanical vibration and the like can be effectively absorbed and dispersed, so that the gas distribution plate and the annular pipe are protected from being damaged by stress concentration.

Description

Technical Field

[0001] The utility model relates to a gas distributor and a fluidized bed gasifier. Background Art

[0002] The existing structure of the distribution plate is a metal distribution plate in a funnel-like shape. The connection between the lower end of the distribution plate and the annular pipe is in a form of direct welding, resulting in stress concentration. During use, due to thermal expansion and contraction, the weld at the lower end cracks, causing the device to stop operating, which will bring huge losses.

[0003] There are many small holes distributed on the distribution plate and metal short pipes are welded to allow the gasifying agent (such as steam) to be blown into the gasifier through the small holes. A layer of anti-wear castable is poured on the distribution plate. During the operation of the gasifier, the castable on the distribution plate is subject to the friction and collision of the materials in the furnace, and the thermal expansion coefficients of the castable and the distribution plate are quite different, so the castable is prone to fall off, blocking the slag discharge port and causing the gasifier to stop operating. After the castable falls off, the metal short pipes are bent, affecting the fluidization state of the materials in the furnace and causing a shutdown. Moreover, during later maintenance, it is extremely easy to bend or even block the metal short pipes.

[0004] Since the short pipes of the distribution plate (gasifying agent inlets) are horizontally oriented towards the center, it causes strong interference to the central area, affecting the jet state in the central pipe area, and the oxygen concentration in the central area will change back and forth in each part, being extremely prone to deviation and causing scar formation in the furnace, affecting production. Summary of the Utility Model

[0005] The technical problem to be solved by the utility model is to overcome the defects in the prior art that the orientation of the gasifying agent inlets of the gas distribution plate is fixed, resulting in interference to the central area of the gasifier and poor durability of the distribution plate, and to provide a gas distributor and a fluidized bed gasifier.

[0006] In a first aspect, the utility model provides a gas distributor, which includes a gas distribution plate and an annular pipe; the gas distribution plate is a conical distribution plate, the bottom of the conical distribution plate is provided with a narrow opening, and the top of the conical distribution plate is provided with a wide opening;

[0007] The conical distribution plate is provided with multiple rows of through holes arranged along its circumference; the extension lines of the central axes of at least some of the through holes intersect with the axis of the conical distribution plate; the extension lines of the central axes of at least some of the through holes deviate from the axis of the conical distribution plate, forming a first preset angle;

[0008] The narrow opening is connected to the annular pipe through a first elbow joint; a Venturi tube is coaxially embedded at one end of the annular pipe close to the narrow opening.

[0009] In the present utility model, multiple rows of through-holes on the conical distribution plate are arranged circumferentially. The extension lines of the central axes of some through-holes intersect with the axis of the conical distribution plate, and some deviate from the axis to form a first preset angle. This design can optimize the gas flow path, reduce turbulence and dead zones during gas flow, and improve the contact efficiency between gas and materials. The Venturi tube utilizes the principle of fluid dynamics to promote the mixing of gas and materials, which helps to improve the efficiency of the entire gasification process. The narrow opening is connected to the annular tube through a first elbow joint, which can effectively absorb and disperse the stress generated due to reasons such as thermal expansion, pressure change, or mechanical vibration, thereby protecting the gas distribution plate and the annular tube from damage caused by stress concentration, extending the service life of the equipment, reducing the frequency of maintenance and replacement, and lowering the long-term operation cost.

[0010] In the present utility model, the first elbow joint may have an integrally formed first connecting portion, a bending portion, and a second connecting portion. The first connecting portion is welded to the gas distribution plate, the second connecting portion is welded to the annular tube, and the first connecting portion and the second connecting portion are connected through the bending portion.

[0011] Among them, the angle between the first connecting portion and the second connecting portion may be the same as the angle between the gas distribution plate and the annular tube.

[0012] Preferably, the angle between the gas distribution plate and the horizontal line may be 30° - 70°; for example, 45°.

[0013] Among them, the thicknesses of the first connecting portion and the second connecting portion may be independently 8 - 40 mm.

[0014] Among them, the radius of curvature of the outer wall at the connection of the first connecting portion and the second connecting portion may be 20 - 100 mm.

[0015] Among them, the distance from the welding point of the first connecting portion and the conical distribution plate to the connection of the bending portion and the first connecting portion may be 30 mm.

[0016] Among them, the distance from the welding point of the second connecting portion and the annular tube to the connection of the bending portion and the second connecting portion may be 30 mm.

[0017] In the present utility model, the apertures of at least some of the through-holes arranged along the direction from the narrow opening to the wide opening may be the same.

[0018] In the present utility model, the first preset angle may be 0 - 20°; for example, 8°.

[0019] In the present utility model, along the direction from the narrow opening to the wide opening, there may be a first through-hole area, a second through-hole area, and a third through-hole area in sequence. The aperture of the through-holes in the first through-hole area is a first aperture, the aperture of the through-holes in the second through-hole area is a second aperture, and the aperture of the through-holes in the third through-hole area is a third aperture. The first aperture is smaller than the second aperture, and the second aperture is smaller than the third aperture.

[0020] In the present utility model, the design of through-hole areas with different apertures helps to form a differential flow field inside the gasifier, thereby optimizing the gas flow in different regions. Through the increasing design where the first aperture is smaller than the second aperture and the second aperture is smaller than the third aperture, it can ensure that the gas flow gradually increases from the narrow opening to the wide opening direction, thus achieving a more uniform intake air distribution.

[0021] Among them, the first aperture can be 4.0 - 6.0 mm, such as 4.7 mm. The second aperture can be 4.0 - 6.0 mm, such as 4.9 mm. The third aperture can be 4.0 - 6.0 mm, such as 5.1 mm.

[0022] Among them, the first through-hole area, the second through-hole area, and the third through-hole area can be respectively provided with 1 - 10 layers of through-holes, such as 5 layers of through-holes.

[0023] Among them, the extension line of the central axis of the through-holes in the first through-hole area can intersect with the central axis at the center of the conical distribution plate.

[0024] Among them, the extension line of the central axis of the through-holes in the second through-hole area can deviate from the central axis at the center of the conical distribution plate by a first preset angle counterclockwise along the circumferential direction of the conical distribution plate.

[0025] Among them, the extension line of the central axis of the through-holes in the third through-hole area can deviate from the central axis at the center of the conical distribution plate by a first preset angle clockwise along the circumferential direction of the conical distribution plate.

[0026] In the present utility model, the design that the extension lines of the central axes of the through-holes in the second through-hole area and the third through-hole area deviate from the central axis enables the gas to flow in a spiral shape in the peripheral area of the fluidized bed, which helps to enhance the mixing of the gas and the material. When the material falls near the conical distribution plate, it is affected by the oxygen blown into from the through-holes and rotates inward, thus forming a fluidized state similar to a fountain form. This improves the uniformity and efficiency of the gasification reaction. Through the design of deviating by a certain angle counterclockwise and clockwise along the circumferential direction, it can enable the gas to form a circulating flow in the fluidized bed, reduce the dead corners of the gas flow, and improve the gasification uniformity of the entire bed layer.

[0027] Among them, the extension line of the central axis of the through hole in the second through hole area can be deviated clockwise by 8° from the central axis at the center of the circular cone of the conical distribution plate along the circumferential direction of the conical distribution plate.

[0028] Among them, the extension line of the central axis of the through hole in the third through hole area can be deviated counterclockwise by 8° from the central axis at the center of the circular cone of the conical distribution plate along the circumferential direction of the conical distribution plate.

[0029] In the present utility model, the conical distribution plate can be a single-layer structure or a multi-layer structure; when the conical distribution plate is a multi-layer structure, each layer of the conical distribution plate is connected in sequence, and the included angle between each layer of the conical distribution plate and the horizontal line increases sequentially from top to bottom.

[0030] In the present utility model, when the conical distribution plate is a multi-layer structure, multiple horizontal included angles are set, and the closer to the lower part, the larger the included angle of the distribution plate. The multi-layer structure design of the conical distribution plate can adapt to materials with different particle sizes. Especially when the particle size of the bottom material is large, increasing the included angle is beneficial to the smooth discharge of the material and reduces blockage. Since the flow of the material at the bottom is smoother, the wear of the gas distributor and the inner wall of the fluidized bed is reduced, and the service life of the equipment is prolonged.

[0031] In a specific embodiment of the present utility model, the conical distribution plate is an integrally formed double-layer structure, the included angle between the upper conical distribution plate and the horizontal line is 45°, and the included angle between the lower conical distribution plate and the horizontal line is 60°.

[0032] In the present utility model, the gas distributor may further include a central pipe, and the central pipe is coaxially arranged inside the annular pipe.

[0033] Among them, there is a gap between the central pipe and the Venturi tube, and the gap is for materials to enter and exit the fluidized bed gasifier. The gap between the central pipe and the Venturi tube provides a channel for materials to enter and exit the fluidized bed gasifier, ensuring that the materials can smoothly enter the gasifier and participate in the gasification reaction. The presence of the central pipe can reduce the deposition of materials in the gas distributor area and avoid the blockage of the gas flow or uneven gasification caused by the deposition of materials.

[0034] In the present utility model, the tube body of the Venturi tube may include a contraction section, a throat, and a diffusion section that are connected in sequence from top to bottom, and the inner surfaces of the contraction section, the throat, and the diffusion section are smoothly transitioned. The local negative pressure formed by the throat helps to suck in the materials and mix them with the gas, enhancing the mixing effect of the materials and the gas.

[0035] Among them, the contraction section starts from the upper opening of the annular pipe, and the included angle between the contraction section and the inner wall of the annular pipe can be 5° - 30°, such as 18°. The included angle between the diffusion section and the inner wall of the annular pipe can be 5° - 30°, such as 11°.

[0036] In the present utility model, a support member may be provided below the Venturi tube. The support member is a metal rod. One end of the metal rod vertically penetrates the inner wall of the annular tube and is fixedly connected. The other end of the metal rod extends towards the central tube, and there is a gap between the other end and the outer wall of the central tube. The arrangement of the metal rod helps to absorb and disperse the vibration caused by the high-speed airflow.

[0037] Wherein, the width of the gap may be 2 mm.

[0038] Wherein, four metal rods may be evenly arranged circumferentially along the annular tube.

[0039] Wherein, the diameter of the metal rod may be 10 mm.

[0040] In the present utility model, the gas distributor may further include an expansion joint, and the expansion joint is arranged around the outer side wall of the annular tube. The expansion joint can compensate for the thermal expansion of the annular tube material caused by temperature changes and maintain the integrity and sealing performance of the gas distributor.

[0041] In a second aspect, the present utility model provides a fluidized bed gasifier, which includes a gasifier shell and the gas distributor as described above.

[0042] In the present utility model, the gasifier shell may include an outer shell and an inner shell, and the outer shell is hermetically connected to the inner shell;

[0043] In the present utility model, the wide opening of the gas distribution plate may be connected to the gasifier shell through a second elbow joint;

[0044] In the present utility model, the annular tube may penetrate the bottom of the gasifier shell.

[0045] In the present utility model, the wide opening of the gas distribution plate may be connected to the inner shell through a second elbow joint.

[0046] In the present utility model, the wide opening of the gas distribution plate is connected to the gasifier shell through a second elbow joint, providing a stable connection point to ensure the sealing performance and structural stability between the gas distributor and the gasifier shell. The second elbow joint can effectively absorb and disperse the stress generated due to thermal expansion, pressure change or mechanical vibration, etc., thereby protecting the gas distribution plate and the gasifier shell from damage caused by stress concentration.

[0047] On the basis of not violating the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present utility model.

[0048] The positive and progressive effects of the present utility model are as follows:

[0049] (1) In the gas distributor of the present utility model, multiple rows of through holes on the conical distribution plate are arranged circumferentially. The extension lines of the central axes of some through holes intersect with the axis of the conical distribution plate, and some deviate from the axis to form a first preset angle. This design can optimize the gas flow path, reduce turbulence and dead zones during gas flow, optimize the gas distribution in the fluidized bed, and improve the contact efficiency between gas and materials.

[0050] (2) In the gas distributor of the present utility model, the Venturi tube utilizes the principle of fluid dynamics to increase the local gas velocity, separate the slag material falling into the distributor, and the material with a high carbon content returns to the gasifier for reuse, which helps to improve the conversion efficiency of the entire gasification process.

[0051] (3) In the gas distributor of the present utility model, the narrow opening is connected to the annular pipe through the first elbow joint, which can effectively absorb and disperse the stress concentration caused by thermal expansion, pressure change or mechanical vibration, etc., thereby protecting the gas distribution plate and the annular pipe from damage caused by stress concentration, extending the service life of the equipment, reducing the frequency of maintenance and replacement, and lowering the long-term operation cost.

[0052] (4) Compared with the prior art in which the distribution plate and the annular pipe are directly welded, the maximum stress of the gas distributor of the present utility model using the elbow joint structure is reduced by more than 20%, and the metal thickness can be appropriately reduced. The equipment is safer and the service life of the equipment is extended by 3 - 5 years. At the same time, the fluidization effect is uniform, the residual carbon at the bottom for slag discharge is lower (from 10% - 15% reduced to 3% - 10%, or even less), and the carbon conversion rate is increased by 1% - 3%. Description of the Drawings

[0053] Figure 1 It is a partial structural schematic diagram of the first elbow joint for Comparative Example 1 and Comparative Example 3;

[0054] Figure 2 It is a sectional view of the gas distributor of Example 1 in the gasifier;

[0055] Figure 3 It is a structural schematic diagram of the first elbow joint of Example 1;

[0056] Figure 4 It is a schematic top sectional view of the through hole of Example 1;

[0057] Figure 5 It is a structural schematic diagram of the gas distribution plate of Example 2;

[0058] Description of the reference numerals: conical distribution plate 1, through hole 2, first elbow joint 3(3’), first connecting part 31, bending part 32, second connecting part 33, annular pipe 4, metal rod 5, fluidized bed gasifier 6, central pipe 7, Venturi tube 8, expansion joint 9, second elbow joint 10. Detailed Embodiments

[0059] The present utility model will be further described below by way of examples, but the present utility model is not limited to the scope of the described examples. For the experimental methods without specific conditions in the following examples, they are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0060] In the embodiments of the present utility model, prefix words such as "first" and "second" are only used to distinguish different described objects, and have no restrictive effect on the position, order, priority, quantity or content of the described objects, etc. The use of ordinal numbers and other prefix words for distinguishing described objects in the embodiments of the present utility model does not constitute a restriction on the described objects. For the statements of the described objects, refer to the description in the claims or the context of the embodiments. It should not constitute an unnecessary restriction due to the use of such prefix words. In addition, in the description of this embodiment, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0061] It should be noted that the gasifying agent in the present utility model refers to the gas medium necessary in the coal gasification process. In this embodiment, the gasifying agent involved in the through holes 2 is mainly steam and a small amount of oxygen, the gasifying agent involved in the central tube 7 is mainly steam and a large amount of oxygen, and the gasifying agent involved in the annular tube 4 is mainly nitrogen or air.

[0062] Embodiment 1

[0063] This embodiment provides a fluidized bed gasifier 6, which includes a gasifier housing and a gas distributor. The gas distributor is as Figure 2 shown, and includes: a gas distribution plate and an annular tube 4; the gas distribution plate is a conical distribution plate 1, the bottom of the conical distribution plate 1 is provided with a narrow opening, and the top is provided with a wide opening; the conical distribution plate 1 is provided with multiple rows of through holes 2 arranged along its circumference; the extension line of the central axis of at least part of the through holes 2 intersects with the axis of the conical distribution plate 1; the extension line of the central axis of at least part of the through holes 2 deviates from the axis of the conical distribution plate 1 to form a first preset angle; the narrow opening is connected to the annular tube 4 through a first elbow 3; a Venturi tube 8 is coaxially embedded at one end of the annular tube 4 near the narrow opening. The gasifying agent enters the interior of the fluidized bed gasifier 6 through the through holes 2, making the materials in the furnace in a fluidized state.

[0064] In this embodiment, as Figure 3As shown, the first elbow joint 3 has an integrally formed first connecting portion 31, a bending portion 32, and a second connecting portion 33. The first connecting portion 31 is welded to the conical distribution plate 1, and the second connecting portion 33 is welded to the annular pipe 4. The first connecting portion 31 and the second connecting portion 33 are connected by the bending portion 32. The angle between the first connecting portion 31 and the second connecting portion 33 is the same as the angle between the conical distribution plate 1 and the annular pipe 4. The thickness of the first connecting portion 31 and the second connecting portion 33 is 30 mm, and in other embodiments, it can be any value between 8 - 40 mm. The material of the conical distribution plate 1 is Incoloy 800HT, which is suitable for high temperature and wear resistance. The curvature radius R of the outer wall at the connection of the first connecting portion 31 and the second connecting portion 33 is 88 mm, and in other embodiments, it can be any value between 20 - 100 mm. The distance L1 from the welding point of the first connecting portion 31 and the conical distribution plate 1 to the connection of the bending portion and the first connecting portion 31 is 30 mm, and the distance L2 from the welding point of the second connecting portion 33 and the annular pipe 4 to the connection of the bending portion and the second connecting portion 33 is 30 mm. The conical distribution plate 1 and the annular pipe 4 are connected by the first elbow joint 3 to form an integral body with a certain flexibility. When the conical distribution plate 1 and the annular pipe are thermally displaced due to heat, the first elbow joint 3 can absorb a part of the deformation amount, and the thermal stress is distributed throughout the first elbow joint 3 instead of concentrating at the weld, preventing the weld from cracking.

[0065] In this embodiment, the surface of the first elbow joint 3 is coated with a wear-resistant layer. The thickness of the wear-resistant layer is 5 - 10 mm, which plays a role in anti-corrosion and wear resistance. The wear-resistant layer is formed by supersonic flame spraying Cr3C2-NiCr75-25; it is sprayed from the welding point of the first connecting portion 31 and the conical distribution plate 1 down to the welding point of the second connecting portion 33 and the annular pipe 4.

[0066] In this embodiment, the multiple rows of through holes 2 on the conical distribution plate 1 are arranged circumferentially. The extension lines of the central axes of some through holes 2 intersect with the axis of the conical distribution plate 1, and some deviate from the axis to form a first preset angle. This design can optimize the gas flow path, reduce turbulence and dead zones during gas flow, and improve the contact efficiency between gas and materials. The Venturi tube 8 can promote the mixing of gas and materials using the principle of fluid dynamics, which helps to improve the efficiency of the entire gasification process.

[0067] In this embodiment, along the direction from the narrow opening to the wide opening, there are a first through-hole area, a second through-hole area, and a third through-hole area in sequence; the aperture of the through-hole 2 in the first through-hole area is a first aperture; the aperture of the through-hole 2 in the second through-hole area is a second aperture; the aperture of the through-hole 2 in the third through-hole area is a third aperture; the first aperture is smaller than the second aperture, and the second aperture is smaller than the third aperture. The design of through-hole areas with different apertures helps to form a differential flow field inside the fluidized bed gasifier 6, thereby optimizing the gas flow in different regions. By the increasing design where the first aperture is smaller than the second aperture and the second aperture is smaller than the third aperture, it can ensure that the gas flow gradually increases from the narrow opening to the wide opening direction, thus achieving a more uniform intake air distribution.

[0068] In this embodiment, the extension line of the central axis of the through-hole 2 in the first through-hole area intersects the central axis at the center of the conical distribution plate 1; the extension line of the central axis of the through-hole 2 in the second through-hole area deviates counterclockwise along the circumferential direction of the conical distribution plate 1 from the central axis at the center of the conical distribution plate 1 by a first preset angle; the extension line of the central axis of the through-hole 2 in the third through-hole area deviates clockwise along the circumferential direction of the conical distribution plate 1 from the central axis at the center of the conical distribution plate 1 by the first preset angle. The design that the extension lines of the central axes of the through-holes 2 in the second through-hole area and the third through-hole area deviate from the central axis of the distribution plate enables the gas to flow in a spiral shape in the peripheral area of the fluidized bed, which helps to enhance the mixing of the gas and the material. When the material falls to the vicinity of the conical distribution plate, affected by the oxygen blown into from the through-hole 2, it rotates and moves inward, thus forming a fluidized state similar to a fountain form. This improves the uniformity and efficiency of the gasification reaction. Through the design of deviating by a certain angle counterclockwise and clockwise along the circumferential direction, it can enable the gas to form a circulating flow in the fluidized bed, reduce the dead corners of the gas flow, and improve the gasification uniformity of the entire bed layer.

[0069] In this embodiment, the apertures of at least some of the through-holes 2 arranged along the direction from the narrow opening to the wide opening are the same. In this embodiment, the first through-hole area, the second through-hole area, and the third through-hole area are respectively provided with 5 rows of through-holes 2, totaling 15 rows, and the apertures of the through-holes 2 in each through-hole area are kept the same. In this embodiment, the first aperture is 4.7 mm, the second aperture is 4.9 mm, and the third aperture is 5.1 mm. The extension line of the central axis of the through-hole 2 in the second through-hole area deviates clockwise along the circumferential direction of the conical distribution plate 1 from the central axis at the center of the conical distribution plate 1 by 8°; the extension line of the central axis of the through-hole 2 in the third through-hole area deviates counterclockwise along the circumferential direction of the conical distribution plate 1 from the central axis at the center of the conical distribution plate 1 by 8°. In other embodiments, the through-holes 2 in each through-hole area are not limited to 5 rows, and the corresponding number can be set as needed.

[0070] In this embodiment, the gas distributor further includes a central pipe 7 coaxially arranged inside the annular pipe 4; there is a gap between the central pipe 7 and the Venturi tube 8 for the material to enter and exit the fluidized bed gasifier 6; the central pipe 7 is the main inlet for the gasifying agent to enter, and the gasifying agent enters the interior of the fluidized bed gasifier 6 from bottom to top. A high-temperature zone (high oxygen concentration zone) is formed in the area directly above the central pipe 7.

[0071] Specifically, the through holes 2 (gasifying agent inlets) in the first to fifth rows on the conical distribution plate 1 are aligned with the central axis of the conical distribution plate 1. The steam pushes the material in the fluidized bed gasifier 6 towards the central area, and then the mixture of steam and oxygen in the central pipe 7 drives it upward. Larger particulate matters fall into the subsequent slag discharge tank through the gap between the central pipe 7 and the annular pipe 4. Figure 4 It shows that the extension line of the central axis of the through hole 2 deflects counterclockwise, the sixth to tenth rows deflect 8° clockwise, the steam pushes the material in the fluidized bed gasifier 6 towards the central area while reducing the disturbance to the central area. The eleventh to fifteenth rows deflect 8° (counterclockwise) in the opposite direction to the sixth to tenth rows to offset the clockwise driving force from the sixth to tenth rows. This makes the position of the central area relatively fixed, stabilizes the reaction state inside the fluidized bed gasifier 6, and achieves the prevention of coking and furnace shutdown caused by gas flow deviation. In this embodiment, the annular gap between the interior of the annular pipe 4 and the central pipe 7 serves as the inlet and slag outlet for another part of the gasifying agent. It should be noted that in other embodiments, the deflection directions of the second through-hole area and the third through-hole area can be reversed, which is not limited here.

[0072] The gas distributor of this embodiment further includes an expansion joint 9, which is annularly arranged on the outer side wall of the annular pipe 4. The expansion joint 9 installed on the annular pipe 4 is used to absorb the longitudinal expansion amount.

[0073] In this embodiment, the conical distribution plate 1 is a single-layer structure, and the angle between the conical distribution plate 1 and the horizontal line is 45°; in other embodiments, the angle between the conical distribution plate 1 and the horizontal line can be designed as other angles according to needs, such as 30°, 60°, etc.

[0074] In this embodiment, a support member is provided below the Venturi tube 8. The support member is a metal rod 5. One end of the metal rod 5 vertically penetrates the inner wall of the annular pipe 4 and is fixedly connected. The other end of the metal rod 5 extends towards the central pipe 7, and there is a gap between the other end and the outer wall of the central pipe 7; in this embodiment, the width of the gap is 2 mm; four metal rods 5 are evenly arranged along the circumferential direction of the annular pipe 4; the diameter of the metal rod 5 is 10 mm. The material of the metal rod 5 is 0Cr25Ni20. The metal rod 5 is provided to prevent the central pipe 7 from swinging when the high-speed gas flow blows into the gasifier 6.

[0075] In this embodiment, the tube body of the Venturi tube 8 includes a contraction section, a throat, and a diffusion section that are connected in sequence from top to bottom. The inner surfaces of the contraction section, the throat, and the diffusion section are smoothly transitioned; the contraction section starts from the upper opening of the annular tube 4, and the included angle between the contraction section and the inner wall of the annular tube 4 is 18°; the included angle between the diffusion section and the inner wall of the annular tube 4 is 11°.

[0076] In this embodiment, the function of the Venturi tube 8 is to allow the gasifying agent inside the annular tube 4 to enter the fluidized bed gasifier 6. When the gasifying agent passes through the throat of the Venturi tube 8, the flow rate becomes faster, causing small particulate matter to return to the fluidized bed gasifier 6 for re-reaction, reaching an agglomerated state. At the same time, by adjusting the amount of the gasifying agent, the slag discharge speed of the fluidized bed gasifier 6 can be adjusted.

[0077] The shell of the fluidized bed gasifier 6 in this embodiment includes an outer shell and an inner shell, and the outer shell and the inner shell are hermetically connected; the wide opening of the gas distribution plate is connected to the gasifier shell through the second elbow joint 10; the annular tube 4 penetrates through the bottom of the gasifier shell. The gasifier shell includes an outer shell and an inner shell, and the outer shell and the inner shell are hermetically connected; the wide opening of the gas distribution plate is connected to the inner shell through the second elbow joint 10.

[0078] In this embodiment, the wide opening of the gas distribution plate is connected to the gasifier shell through the second elbow joint 10, providing a stable connection point to ensure the sealing and structural stability between the gas distributor and the gasifier shell. The second elbow joint 10 can effectively absorb and disperse the stress generated due to reasons such as thermal expansion, pressure change, or mechanical vibration, thereby protecting the gas distribution plate and the gasifier shell from damage caused by stress concentration.

[0079] In this embodiment, the through holes 2 on the conical distribution plate 1 are horizontally and circularly distributed. There are 15 rows (but not limited to 15 rows) from bottom to top and 655 holes. There is one hole diameter for every 5 rows, and there are three specifications of φ4.7mm, φ4.9mm, and φ5.1mm respectively. When the fluidized bed gasifier 6 is in production operation, the conical distribution plate 1 expands due to heat, elongating longitudinally along the distribution plate. The annular tube 4 elongates in the up and down directions and expands outward at the same time; when the conical distribution plate 1 expands obliquely upward, the thermal stress is absorbed by the second elbow joint 10. When it expands obliquely downward, the thermal stress is absorbed by the first elbow joint 3, and at the same time, a vertically downward force acts on the annular tube 4, and the force of the annular tube 4 expanding up and down due to thermal stress is absorbed by the expansion joint 9. In this way, the forces on the entire distribution plate 1 and the annular tube 4 are relatively uniform, eliminating stress concentration, and thus extending the service life. Among them, the conical distribution plate 1 is in a funnel shape. The through holes 2 on the conical distribution plate 1 are the channels for the gasifying agent to enter the gasifier interior. Among them, the conical distribution plate 1 is in a funnel shape. The through holes 2 on the conical distribution plate 1 are the channels for the gasifying agent to enter the gasifier interior.

[0080] In the cold state, the material state in the fluidized bed gasifier 6 is as follows: The gasifying agent in the central tube 7 is blown vertically upward at a high speed into the interior of the fluidized bed gasifier 6, driving the materials inside the fluidized bed gasifier 6 to move upward. When the materials reach the vertex, they disperse in all directions and then move downward under the influence of gravity. When the materials fall near the conical distribution plate 1, they are affected by the oxygen blown into from the through holes 2 and rotate inward to form a fluidized state similar to a fountain. Due to the 8° angle between the through holes 2 and the central axis of the distribution plate, larger particulate matters move downward under the action of centrifugal force, and smaller particulate matters move toward the central area (high-temperature area) and continue to participate in the reaction. In this way, the influence of the steam blown into the central area from the conical distribution plate 1 on the central area (high-temperature area or high oxygen concentration area) is reduced, and the jet state of the central tube 7 is stabilized, so that the materials in the furnace reach a more reasonable fluidized state.

[0081] In the hot state, since most of the oxygen is blown into the interior of the fluidized bed gasifier 6 from the central tube 7, a rich oxygen area is formed in the upper part of the central tube 7. The reaction between oxygen and coal generates a large amount of heat, which is also called a high-temperature area. The temperature in the high-temperature area is controlled near the ash melting point of the coal, so that the ash in the coal agglomerates. After agglomeration, it grows from small to large. When the ash agglomeration particles become larger, they fall outward and downward under the influence of gravity and fall into the annular gap between the annular tube 4 and the central tube 7 and are discharged into the slag lock.

[0082] In this embodiment, the multiple rows of through holes 2 on the conical distribution plate 1 are arranged circumferentially. The extension lines of the central axes of some of the through holes 2 intersect with the axis of the conical distribution plate 1, and some deviate from the axis to form a first preset angle. This design can optimize the gas flow path, reduce turbulence and dead zones during gas flow, and improve the contact efficiency between gas and materials. The Venturi tube 8 can promote the mixing of gas and materials by using the principle of fluid dynamics, which helps to improve the efficiency of the entire gasification process. The narrow opening is connected to the annular tube 4 through the first elbow joint 3, which can effectively absorb and disperse the stress generated due to reasons such as thermal expansion, pressure change or mechanical vibration, thereby protecting the gas distribution plate and the annular tube 4 from damage caused by stress concentration, extending the service life of the equipment, reducing the frequency of maintenance and replacement, and reducing the long-term operation cost.

[0083] Embodiment 2

[0084] The difference from Embodiment 1 is that the conical distribution plate 1 is a multi-layer structure, and each layer of conical distribution plate is connected in sequence. The angle between each layer of conical distribution plate 1 and the horizontal line increases sequentially from top to bottom. As Figure 5As shown, the conical distribution plate 1 is a double-layer structure formed by integral molding. The angle between the upper conical distribution plate 1 and the horizontal line is 45°, and the angle between the lower conical distribution plate 1 and the horizontal line is 60°. The distribution plate is divided into multiple layers with various horizontal angles. The closer to the lower part, the larger the angle of the distribution plate. The multi-layer structure design of the conical distribution plate 1 can adapt to materials with different particle sizes. Especially when the particle size of the bottom material is relatively large, increasing the angle is beneficial to the smooth discharge of the material and reduces blockage. Since the material flows more smoothly at the bottom, the wear of the material on the gas distributor and the inner wall of the fluidized bed is reduced, and the service life of the equipment is extended. In other embodiments, the conical distribution plate 1 can be three layers or more.

[0085] Comparative Example 1

[0086] Compared with Example 1, the difference is that the connection form between the conical distribution plate 1 and the annular pipe 4 is welding, as Figure 1 . The thermal stress of the weld is relatively concentrated and prone to cracking.

[0087] Comparative Example 2

[0088] Compared with Example 2, the difference is that the conical distribution plate 1 adopts a single aperture - 5 mm, and there are 12 (3×4) rows of through holes 2.

[0089] Comparative Example 3

[0090] Compared with Example 1, the difference is that the conical distribution plate 1 adopts a single aperture - 5 mm, and there are 12 (3×4) rows of through holes 2. The conical distribution plate 1 and the annular pipe 4 are directly welded, as Figure 1 . The venturi tube is not provided in the annular pipe 4.

[0091] Effect Example

[0092] Compared with Comparative Example 1, in Example 1, the maximum stress of the kink joint structure is reduced by more than 20%, and the metal thickness can be appropriately reduced. Specifically, by using the finite element analysis calculation model, finite element models of the two distribution plate structures are established respectively. Considering working conditions such as cold start, hot reaction, and shutdown, the above conclusions are obtained by stress evaluation of the two distribution plates. During the model optimization process, the thickness of some metal plates is appropriately thinned.

[0093] In Comparative Example 2, the distribution plate structure of the present utility model was not adopted. Under the working conditions of a coal feeding rate of 11 t / h, a fixed carbon content of 50%, and an ash content of 18%, the bottom slag discharge amount was 2.25 t / h, and the carbon content in the bottom slag was 12%. In Example 2, the distribution plate openings were divided into three rows, and the aperture diameters were optimized according to the pressure drop in the bed layer. The aperture diameters of the three layers were different, and the opening directions caused the fluidization direction of the bed layer to not only be in the vertical direction but also have a certain lateral rotation, increasing the residence time of the coal in the bed layer, deepening the reaction process, and making the carbon content in the bottom slag lower. The distribution plate adopted a multi-layer structure with a small upper included angle and a large lower included angle, which promoted the bottom ash slag to more easily fall into the annular pipe and was not easily accumulated here. The angle between the lower distribution plate and the annular pipe was more conducive to the ash slag falling, reducing the abrasion of the annular pipe fluidization gas on the connection between the two, and extending the service life of the distribution plate. The slag discharge annular pipe adopted a Venturi tube type. During slag discharge, the falling bottom slag was fluidized and screened, so that the ash slag with a lower carbon content and a higher density was screened and fell, while the ash slag with a higher carbon content, due to a lower density, was re-blown into the bed layer to continue the reaction. The carbon content in the bottom slag was reduced to 5.61% or even lower, and the carbon conversion rate increased by 1.82% compared with Comparative Example 2.

[0094] In Comparative Example 3, after gasification operation, under the working conditions of a gasification furnace temperature above 900 °C, an inlet coal mass of 11 T / h, a fixed carbon content of 50%, and an ash content of 18%, after about 1 year of operation, inspection found that the bottom of the distribution plate was severely worn and the welds were cracked, requiring repair. The carbon content of the operating bottom slag was relatively high, about 12%.

[0095] Although the specific implementation manners of the present utility model have been described above, those skilled in the art should understand that this is only an example. The protection scope of the present utility model is defined by the appended claims. Without departing from the principles and essence of the present utility model, those skilled in the art can make various changes or modifications to these implementation manners, but these changes and modifications all fall within the protection scope disclosed by the present utility model.

Claims

1. A gas distributor, characterized in that: It includes a gas distribution plate and a ring pipe; The gas distribution plate is a conical distribution plate, the bottom of the conical distribution plate is provided with a narrow opening, and the top of the conical distribution plate is provided with a wide opening; The conical distribution plate is provided with a plurality of rows of through holes arranged along its circumference; at least part of the central axis extension lines of the through holes intersect with the axis of the conical distribution plate; at least part of the central axis extension lines of the through holes deviate from the axis of the conical distribution plate to form a first preset angle; The narrow opening is connected to the annular tube through a first elbow joint; a venturi tube is coaxially embedded in the annular tube at one end close to the narrow opening.

2. The gas distributor according to claim 1, characterized in that The first elbow joint has an integrally formed first connection part, a bending part and a second connection part, the first connection part is welded to the gas distribution plate, the second connection part is welded to the ring tube, and the first connection part and the second connection part are connected through the bending part; the angle between the first connection part and the second connection part is consistent with the angle between the gas distribution plate and the ring tube; the angle between the gas distribution plate and the horizontal line is 30°-70°; the distance from the welding point of the first connection part and the conical distribution plate to the connection between the bending part and the first connection part is 30mm, and the distance from the welding point of the second connection part and the ring tube to the connection between the bending part and the second connection part is 30mm; the thickness of the first connection part is 8-40mm; the thickness of the second connection part is 8-40mm; the radius of curvature of the outer wall at the connection between the first connection part and the second connection part is 20-100mm; The apertures of at least some of the through holes arranged along the direction from the narrow opening to the wide opening are consistent; The first preset angle is 0-20°.

3. The gas distributor according to claim 1, characterized in that Along the direction from the narrow opening to the wide opening, there are the first through hole area, the second through hole area and the third through hole area in sequence, the aperture of the through holes in the first through hole area is the first aperture, the aperture of the through holes in the second through hole area is the second aperture, the aperture of the through holes in the third through hole area is the third aperture, the first aperture is smaller than the second aperture, and the second aperture is smaller than the third aperture; the first aperture is 4.0-6.0mm; the second aperture is 4.0-6.0mm, and the third aperture is 4.0-6.0mm; the first through hole area is provided with 1-10 layers of through holes; the second through hole area is provided with 1-10 layers of through holes; the third through hole area is provided with 1-10 layers of through holes.

4. The gas distributor according to claim 3, characterized in that The extension line of the central axis of the through hole in the first through hole zone intersects with the central axis at the center of the cone distribution plate; The extension line of the central axis of the through hole in the second through hole zone deviates counterclockwise from the central axis at the center of the conical distribution plate by a first preset angle along the circumference of the conical distribution plate; An extension line of a central axis of the through hole in the third through hole zone deviates clockwise from a central axis at the center of the conical distribution plate by a first preset angle along the circumference of the conical distribution plate.

5. The gas distributor according to claim 1, characterized in that The conical distribution plate is a single-layer structure or a multi-layer structure; when the conical distribution plate is a multi-layer structure, each layer of the conical distribution plates is connected in sequence, and the angle between each layer of the conical distribution plates and the horizontal line increases from top to bottom; The conical distribution plate is an integrally formed double-layer structure, the angle between the upper conical distribution plate and the horizontal line is 45°, and the angle between the lower conical distribution plate and the horizontal line is 60°.

6. The gas distributor according to claim 1, characterized in that It also includes a central tube, which is coaxially arranged in the annular tube; there is a gap between the central tube and the venturi tube; The tube body of the venturi tube includes a contraction section, a throat and a diffusion section which are connected in sequence from top to bottom, and the inner surfaces of the contraction section, the throat and the diffusion section have a smooth transition; the contraction section starts from the upper opening of the annular tube, and the angle between the contraction section and the inner wall of the annular tube is 5°-30°; the angle between the diffusion section and the inner wall of the annular tube is 5°-30°.

7. The gas distributor according to claim 6, characterized in that A support member is provided below the venturi tube, and the support member is a metal rod. One end of the metal rod vertically penetrates the inner wall of the ring tube and is fixedly connected, and the other end of the metal rod extends toward the center tube and there is a gap with the outer wall of the center tube; the width of the gap is 2 mm; the diameter of the metal rod is 10 mm; four metal rods are evenly arranged along the circumference of the ring tube.

8. The gas distributor according to claim 1, characterized in that The gas distributor also includes an expansion joint, and the expansion joint is arranged on the outer side wall of the annular tube.

9. A fluidized bed gasifier, characterized in that: It comprises a gasifier shell and a gas distributor as claimed in any one of claims 1 to 8.

10. The fluidized bed gasifier according to claim 9, characterized in that: The gasifier shell comprises an outer shell and an inner shell, wherein the outer shell is tightly connected to the inner shell; the wide opening of the gas distribution plate is connected to the inner shell via a second elbow; The wide opening of the gas distribution plate is connected to the gasifier shell through a second elbow; The annular pipe penetrates through the bottom of the gasifier shell.

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