Air cap of circulating fluidized bed

Abstract

A circulating fluidized bed hood comprises an outer cover and an air pipe, the air pipe is connected with the outer cover and protrudes relative to the outer cover so that at least part of the air pipe can be located outside the outer cover, an inner cavity is formed in the outer cover and communicated with the air pipe, and air holes are formed in the side face of the outer cover and communicated with the inner cavity. The surfaces of parts, in contact with airflow, on the flowing path from the air pipe to the air holes are all covered with enamel layers, so that the airflow can be prevented from entering the air chamber from the air cap, residues carried by the airflow from the air holes can be reduced, the risk that the air cap is blocked is reduced, furnace shutdown accidents are reduced, the labor cost of manual removal is reduced, and the production efficiency is improved. The flow guide structure can reduce the resistance of airflow entering the circulating fluidized bed from the air chamber, and the efficiency of the fan is improved.

Description

Technical Field

[0001] The utility model belongs to the field of circulating fluidized bed equipment, and in particular relates to a circulating fluidized bed hood. Background Art

[0002] The hood is one of the core components of a circulating fluidized bed boiler. Its main function is to control and guide the airflow so that the air entering the fluidized bed has a second diversion and has a certain kinetic energy to drive the fluidized combustion of the material above, thereby achieving uniform distribution of the fluidized air and disturbing the particles at the bottom of the furnace.

[0003] Conventional boiler hoods are usually made of heat-resistant and wear-resistant cast iron, cast steel or alloy steel. The most common form is a bell-shaped hood with horizontal holes at the bottom. In actual use, problems such as air duct blockage and reduced air volume are prone to occur, causing local overheating and coking of the boiler.

[0004] Moreover, in some boilers using special fuels such as sludge incinerators and garbage furnaces, since the primary air contains various residues such as dried sludge, garbage bin odor, dust, volatile organic compounds, etc., long-term operation will cause blockage and scaling of the inner wall of the wind hood, resulting in poor fluidization, affecting the long-term continuous operation of the unit and increasing the maintenance workload. Utility Model Content

[0005] In view of the above-mentioned prior art, the purpose of the utility model is to provide a more convenient and practical circulating fluidized bed hood.

[0006] The technical solution of the utility model is achieved as follows: a circulating fluidized bed hood, including an outer cover and an air duct, the air duct is connected to the outer cover and is protruding relative to the outer cover so that the air duct is at least partially located outside the outer cover, an inner cavity is provided inside the outer cover and is connected to the air duct, an air hole is provided on the side of the outer cover, the air hole is connected to the inner cavity, a guide structure is provided on the flow path from the air duct to the air hole, and the surfaces of the parts in contact with the airflow on the flow path from the air duct to the air hole are all covered with an enamel layer.

[0007] The beneficial effects of this design are: in this way, the residue is carried into the fluidized bed from the air hole as much as possible, the residual residue of the primary air in the inner cavity of the hood is reduced, the risk of air hole blockage is reduced, and the labor cost of manual removal is reduced. The increase of the guide structure can reduce the resistance of the air flow from the air chamber into the circulating fluidized bed, and improve the efficiency of the fan. The enamel surface is dense, smooth, and non-porous. The surface gas flow resistance is small, resistant to smoke erosion, dust is not easy to adhere, and it has the performance of high temperature resistance and corrosion resistance. In this solution, the air flow channel is covered with an enamel layer, which can effectively reduce dust blockage.

[0008] Furthermore, the outer cover includes an upper cover and a base, and the upper cover is detachably mounted on the base. The inner wall of the upper cover forms a cylindrical surface and matches the outer wall of the base which forms a cylindrical surface. The inner wall of the upper cover is provided with a locking protrusion, and the outer wall of the base is provided with a locking groove. The locking protrusion enters the locking groove to lock the upper cover and the base together, so that when cleaning is required, the upper cover can be directly opened to clean the inner cavity. Under normal circumstances, no tools are required and the upper cover can be manually rotated for disassembly. If it has been used for a long time, tools can be used to disassemble it. This is also very convenient to install.

[0009] Furthermore, the locking groove includes an axial groove and a circumferential groove. The axial groove and the circumferential groove are arranged at intervals so that when the upper cover is installed on the base, the locking protrusion must both rotate circumferentially and move axially in the locking groove. In this way, it needs to rotate and move linearly to prevent the upper cover from automatically detaching from the base under strong airflow and vibration, causing the hood to fail. Generally, short-term vibration or airflow is regular so that the upper cover will only move or rotate in a certain direction. In this way, locking grooves in different directions can ensure that it is basically impossible to automatically unlock the upper cover and cause it to detach from the base within a period of time, thereby improving the reliability of the hood.

[0010] Furthermore, locking bevel teeth are provided on the side of the circumferential groove. When the locking protrusion rotates in the circumferential groove, it contacts the locking bevel teeth so that the circumferential rotation resistance of the locking protrusion along the locking direction is smaller than the resistance of rotation in the opposite direction of the locking direction. In this way, the locking protrusion tends to move in the locking direction under irregular vibration, thereby further ensuring the stability and reliability of the locking.

[0011] Furthermore, the locking groove includes a first locking groove and a second locking groove, the first locking groove includes an oblique axial groove, a first axial groove, a first circumferential groove, a second axial groove and a second circumferential groove, the first circumferential groove and the second circumferential groove extending in opposite directions, the second locking groove includes a straight axial groove, a first axial groove, a first circumferential groove, a second axial groove and a second circumferential groove, the straight axial groove extends axially from the first axial groove, and the oblique axial groove extends circumferentially from the first axial groove and then extends axially. This design makes the unlocking process more complicated, greatly reducing the risk of the upper cover accidentally detaching from the base. In this way, if the upper cover is to be detached from the base, it needs to be rotated circumferentially first, and the locking protrusion is moved from The second circumferential groove moves to the second axial groove, then moves axially out of the second axial groove and enters the first circumferential groove, and then rotates in the opposite direction from the first circumferential groove to enter the first axial groove. At this time, the locking protrusion in the second locking groove can be disengaged from the second locking groove, but the locking protrusion in the first locking groove is locked by being obliquely inserted into the axial groove, and it is also necessary to move axially to unlock after a certain angle of circumferential rotation. During this unlocking action, the upper cover must remain in an inclined state, that is, the locking protrusion must be disengaged from the second locking groove, otherwise it cannot be rotated and cannot be unlocked. This action is very complicated and basically cannot occur under accidental circumstances, that is, it basically will not be unlocked, which greatly improves the safety of locking.

[0012] Furthermore, an air outlet is provided on the side of the air duct, and a covering plate is provided at the air outlet position. The covering plate is hingedly installed in a rotatable manner relative to the air outlet. The airflow in the air duct can push the covering plate to open the air outlet, and the airflow from outside the air duct to inside the air duct can push the covering plate to close the air outlet.

[0013] Furthermore, a guide plate is provided at the air hole of the inner cavity to guide the internal airflow to the air hole position, so that the airflow can also move the residue that accidentally enters the inner cavity to the air hole position under the guidance of the guide plate and leave the inner cavity with the airflow. The guide plate can also reduce turbulence, greatly reduce the resistance of the airflow flow when the airflow moves at high speed, and improve the working efficiency of the fan.

[0014] Furthermore, a spiral blade is provided between the guide plate and the cover plate to guide the airflow into a spiral flow, so that part of the residue entering the inner cavity can be removed from the air hole by utilizing the airflow.

[0015] Furthermore, the spiral blades, the guide plate and the cover plate are fixed on the same cylinder to form an integrated guide structure, which is convenient for replacement and installation, and can reduce maintenance labor costs.

[0016] Furthermore, a floating cover is provided on the base to divide the inner cavity into an upper cavity and a lower cavity. The spiral blades, guide plates and sealing plates are all located in the lower cavity. When the pressure of the lower cavity is greater than that of the upper cavity and the pressure difference reaches a certain value, the floating cover can be pushed upward. In this way, when the fan needs to work at high power under certain circumstances, the pressure difference increases. By pushing the floating cover upward, a large gap is formed between the upper cover and the base, and the airflow can enter the circulating fluidized bed from the gap, which reduces the airflow resistance and further improves the working efficiency of the fan. In addition, when the air holes are blocked, the pressure of the lower cavity is greater than that of the upper cavity and the pressure difference reaches a certain value, the floating cover can also be pushed upward. In this way, the stability of the circulating fluidized bed can be improved. Even if some air holes are blocked, a large amount of airflow will enter the circulating fluidized bed to ensure normal combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an overall three-dimensional schematic diagram of a circulating fluidized bed hood of the utility model;

[0018] Figure 2 This is a top view schematic diagram of a circulating fluidized bed hood of the utility model;

[0019] Figure 3 The utility model is a circulating fluidized bed hood Figure 2 Half-section diagram of the middle AA position;

[0020] Figure 4 This is a schematic diagram of an upper cover of a circulating fluidized bed hood according to the utility model;

[0021] Figure 5It is a three-dimensional schematic diagram of a circulating fluidized bed air hood without an upper cover according to the utility model;

[0022] Figure 6 It is a three-dimensional schematic diagram of a circulating fluidized bed air hood without an upper cover according to the utility model;

[0023] Figure 7 It is a top view schematic diagram of a circulating fluidized bed air hood without an upper cover according to the utility model;

[0024] Figure 8 It is a three-dimensional schematic diagram of a circulating fluidized bed air hood without an upper cover according to the utility model;

[0025] Fig. 9 It is a top view schematic diagram of a guide plate of a circulating fluidized bed air hood without an upper cover according to the utility model;

[0026] Fig.10 It is a three-dimensional schematic diagram of the diversion structure of the utility model;

[0027] Fig.11 This is a three-dimensional schematic diagram of the air duct of the utility model;

[0028] Fig.12 It is a schematic diagram of the locking helical teeth contacting the locking protrusion of the utility model. DETAILED DESCRIPTION

[0029] As required, detailed embodiments of the present invention are disclosed herein, but it should be understood that the disclosed embodiments are only exemplary of the present invention, and the present invention may be implemented in different and alternative forms. The drawings are not necessarily drawn to scale, and certain features may be exaggerated or reduced to show the details of specific components. Therefore, the specific structural and functional details disclosed herein should not be understood as having a limiting meaning, but only as a representative basis to teach those skilled in the art to adopt the present invention differently. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0030] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5As shown, a circulating fluidized bed hood comprises an outer cover 1 and an air duct 2, wherein the air duct 2 is connected to the outer cover 1 and is protruded relative to the outer cover 1 so that the air duct 2 is at least partially located outside the outer cover 1, an inner cavity 3 is provided inside the outer cover 1 and is connected to the air duct 2, an air hole 4 is provided on the side of the outer cover 1, and the air hole 4 is connected to the inner cavity 3, a guide structure 5 is provided on the flow path from the air duct 2 to the air hole 4, under the action of the guide structure 5, the flow resistance of the airflow flowing from the air duct 2 to the air hole 4 at the same flow rate is less than the flow resistance from the air hole 4 to the air duct 2, and the surfaces of the parts in contact with the airflow on the flow path from the air duct 2 to the air hole 4 are all covered with an enamel layer.

[0031] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the outer cover 1 includes an upper cover 6 and a base 7. The upper cover 6 and the base 7 are in a cylindrical structure. The upper cover 6 is detachably mounted on the base 7. The inner wall of the upper cover 6 is a cylindrical surface that matches the outer wall of the base 7. The inner wall of the upper cover 6 is provided with a locking protrusion 8, and the outer wall of the base 7 is provided with a locking groove 10. The locking protrusion 8 enters the locking groove 10 to lock the upper cover 6 and the base 7 together.

[0032] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the upper end of the upper cover 6 is provided with a T-shaped convex rib 9 for direction identification. The convex rib 9 has the function of installation and removal and can also be designed into other shapes. The outer side of the upper cover 6 is provided with a disassembly hole 11. The disassembly hole 11 can be a through hole or a blind hole. The blind hole is easy to be blocked, and the through hole is convenient for dredging. In addition, the through hole can also function as a vent 4 under certain circumstances. The inner side of the upper cover 6 is provided with four locking protrusions 8. The locking protrusions 8 are rectangular or spiral blade-shaped, and can also be directly set to a cylindrical shape. Of course, the locking effect of the cylindrical shape is poor. The locking effect is better when a serrated locking surface is set on the locking protrusion 8 and contacts the locking groove 10.

[0033] like Figure 5 and Figure 6 As shown, the locking groove 10 includes an axial groove 12 and a circumferential groove 13. The axial groove 12 and the circumferential groove 13 are arranged at intervals so that the locking protrusion 8 can rotate circumferentially and move axially in the locking groove 10 when the upper cover 6 is installed on the base 7. The circumferential groove 13 can not only be extended in the circumferential direction, but also extend a certain distance in the axial direction to form a spiral structure, just like a thread, it will be basically locked by a force in the linear direction, and it may be loosened only when a torque is generated by an external force.

[0034] like Figure 5 and Figure 6As shown, the side of the circumferential groove 13 is provided with a locking bevel tooth 14, and the locking protrusion 8 contacts the locking bevel tooth 14 when rotating in the circumferential groove 13, so that the circumferential rotation resistance of the locking protrusion 8 along the locking direction is smaller than the rotation resistance in the opposite direction of the locking direction. Fig.12 As shown, the two action surfaces of the locking bevel tooth 14 have different angles, so that the resistance to moving the locking protrusion 8 along the angle is smaller, and the resistance to moving the locking protrusion 8 in the opposite direction is larger. When there is no force in a specific direction, it is usually mainly a back and forth vibration, so that the locking protrusion 8 moves both forward and reverse relative to the locking bevel tooth 14, but even if the two directions act for the same time, it is obvious that the displacement along the direction of the bevel tooth is greater. In this way, general vibration will make the locking protrusion 8 lock more tightly, and it is not easy for the upper cover 6 and the base 7 to accidentally separate.

[0035] like Figure 5 and Figure 6 As shown, the locking groove 10 includes a first locking groove 16 and a second locking groove 17, and the first locking groove 16 and the second locking groove 17 are arranged on different sides of the base 7. The first locking groove 16 includes an oblique axial groove 15, a first axial groove 18, a first circumferential groove 19, a second axial groove 20 and a second circumferential groove 21, and the first circumferential groove 19 extends in opposite directions to the second circumferential groove 21. The second locking groove 17 includes a straight axial groove 22, a first axial groove 18, a first circumferential groove 19, a second axial groove 20 and a second circumferential groove 21, and the straight axial groove 22 extends axially from the first axial groove 18, the oblique axial groove 15 extends circumferentially from the first axial groove 18 and then extends axially. The difference between the first locking groove 16 and the second locking groove 17 is that the oblique axial groove 15 is different from the straight axial groove 22. In the embodiment, two first locking grooves 16 and two second locking grooves 17 are provided, or only one first locking groove 16 is provided. The first locking groove 16 must be less than half. When the upper cover 6 is installed on the base 7, when the locking protrusion 8 enters the oblique locking groove 10 at the beginning, the locking protrusions 8 at other positions are The locking protrusion 8 is not aligned with the straight-entry axial groove 22 and therefore cannot enter. The upper cover 6 is in an inclined position relative to the base 7. Only after the locking protrusion 8 rotates circumferentially in the oblique axial groove 15 for a certain angle, the locking protrusion 8 is aligned with the straight-entry axial groove 22, so that the locking protrusion 8 moves axially into the first axial groove 18 at the bottom of the straight-entry axial groove 22, and the locking protrusion 8 in the first locking groove 16 also enters the first axial groove 18 from the oblique axial groove 15. After that, the movement or rotation of the locking protrusion 8 in the first locking groove 16 and the second locking groove 17 is the same. The change in the extension direction of the locking groove 10 can help the stability of the locking, but the unlocking process is also more complicated. For example, the locking helical teeth 14 can only be set on one side of the locking groove 10, which makes unlocking more convenient. If there are helical teeth on both sides, it is difficult to achieve manual unlocking. A third axial groove 23 can also be set at the bottom of the second circumferential groove 21, and the second circumferential groove 21 can be connected to the middle position of the third axial groove 23. In this way, it is not possible to move the locking protrusion 8 to a position that is too high or too low to unlock, so the possibility of accidental unlocking is also lower.

[0036] like Figure 8 , Fig. 9 , Fig.10 and Fig.11 As shown, an air outlet 24 is provided on the side of the air duct 2, and a covering plate 25 is provided at the position of the air outlet 24. The covering plate 25 is hingedly installed in a manner that it can rotate relative to the air outlet 24. The airflow in the air duct 2 can push the covering plate 25 to open the air outlet 24, and the airflow from the outside of the air duct 2 to the inside of the air duct 2 can push the covering plate 25 to close the air outlet 24. To ensure that the covering plate 25 can close the air outlet 24 during reverse flow, the rotation range of the covering plate 25 should be limited, that is, when the covering plate 25 is open, the covering plate 25 has a certain cross-sectional area in the radial direction so that the reverse circumferential airflow can drive the covering plate 25 to close. In this case, the opening angle of the covering plate 25 is generally 30 degrees to 150 degrees, or the covering plate 25 has a smaller rotation angle, and the opening angle of the covering plate 25 is generally required to be less than 45 degrees. Under the action of the reverse airflow, the pressure on the side close to the airflow becomes smaller, so that the covering plate 25 closes the air outlet 24 under the reverse airflow, which is similar to the design of a one-way valve. The air duct 2 can be connected to the base 7 via a thread 34 .

[0037] like Figure 8 , Fig. 9 , Fig.10 and Fig.11 As shown, the inner cavity 3 is provided with a guide plate 26 at the air hole 4 to guide the internal airflow to the position of the air hole 4. In the case of downstream flow, that is, when the airflow flows from the air duct 2 to the air hole 4, the guide plate 26 generally needs to move radially from the inside to the outside and then move axially from the top to the bottom. Part of the airflow needs to be entrained and move circumferentially, and then move radially along the air hole 4 when it reaches the position of the air hole 4. Downstream flow is the normal working airflow, the smaller the airflow resistance, the better. In countercurrent flow, the guide plate 26 can change the radially moving airflow into circumferential movement. The circumferential airflow can use centrifugal force to separate part of the residue to avoid entering the air duct 2. The cyclone airflow can also use the cyclone airflow to close the cover plate 25, so that the cover plate 25 can be opened at a larger angle to reduce the resistance of the cover plate 25 to the gas in downstream flow.

[0038] like Figure 7 , Figure 8 and Fig.10 As shown, a spiral blade 27 is provided between the guide plate 26 and the cover plate 25 to guide the airflow into a spiral flow. The spiral airflow can generate centrifugal force to transfer the solid residue in the cavity to the position of the inner wall air hole 4 and further use the airflow to bring the residue out of the inner cavity 3. When the airflow flows in the reverse direction, the spiral blade 27 can generate a circumferential airflow, making it easier to close the cover plate 25, which has a good blocking effect on the pulsating airflow generated by the fluidized bed, avoiding shutdown accidents caused by reverse flow.

[0039] like Figure 8 , Fig. 9, Fig.10 and Fig.11 As shown, the spiral blades 27, the guide plate 26 and the cover plate 25 are fixed on the same cylinder 28 to form an integrated guide structure 5. The cylinder 28 is provided with an upper fixing ring 29 and a lower fixing ring 30 to hinge the cover plate 25. In order to reduce the cost, thin steel plates can be used for production. In order to increase the corrosion resistance, enamel materials can be used to treat the surface. That is, the spiral blades 27, the guide plate 26 and the cover plate 25 are welded to the cylinder 28 and then surface treated. They are then installed on the air duct 2 of the hood, and the base 7 can be processed with corresponding grooves to fix the guide plate 26.

[0040] like Figure 3 As shown, a floating cover 33 is provided on the base 7 to divide the inner cavity 3 into an upper cavity 31 and a lower cavity 32. The spiral blade 27, the guide plate 26 and the cover plate 25 are all located in the lower cavity 32. When the pressure of the lower cavity 32 is greater than that of the upper cavity 31 and the pressure difference reaches a certain value, the floating cover 33 can be pushed upward. The floating cover 33 is generally designed to be a semi-closed barrel structure. Under normal circumstances, the floating cover 33 cooperates with the base 7 to form two independent cavities, the lower cavity 32 and the upper cavity 31. Only when the pressure difference is too large, the upper cavity 31 and the lower cavity 32 are connected to form one cavity. That is, the guide structure 5 will have a great effect during normal operation, but the effect will be reduced under special circumstances.

Claims

1. A circulating fluidized bed hood, comprising an outer cover (1) and an air duct (2), wherein the air duct (2) is connected to the outer cover (1) and is arranged to protrude relative to the outer cover (1) so that at least a portion of the air duct (2) is located outside the outer cover (1), an inner cavity (3) is provided inside the outer cover (1) and is communicated with the air duct (2), and an air hole (4) is provided on a side surface of the outer cover (1), and the air hole (4) is communicated with the inner cavity (3), characterized in that: The surfaces of the components in contact with the air flow on the flow path from the air duct (2) to the air hole (4) are all covered with an enamel layer.

2. The circulating fluidized bed hood according to claim 1, characterized in that: The outer cover (1) comprises an upper cover (6) and a base (7); the upper cover (6) is detachably mounted on the base (7); the inner wall of the upper cover (6) forms a cylindrical surface and matches the outer wall of the base (7) forms a cylindrical surface; the inner wall of the upper cover (6) is provided with a locking protrusion (8); the outer wall of the base (7) is provided with a locking groove (10); the locking protrusion (8) enters the locking groove (10) so as to lock the upper cover (6) and the base (7) together.

3. The circulating fluidized bed hood according to claim 2, characterized in that: The locking groove (10) comprises an axial groove (12) and a circumferential groove (13), wherein the axial groove (12) and the circumferential groove (13) are arranged at intervals so that when the upper cover (6) is mounted on the base (7), the locking protrusion (8) can both rotate circumferentially and move axially in the locking groove (10).

4. The circulating fluidized bed hood according to claim 3, characterized in that: The side surface of the circumferential groove (13) is provided with a locking bevel tooth (14), and when the locking protrusion (8) rotates in the circumferential groove (13), it contacts the locking bevel tooth (14), so that the circumferential rotation resistance of the locking protrusion (8) in the locking direction is smaller than the rotation resistance in the direction opposite to the locking direction.

5. The circulating fluidized bed hood according to claim 4, characterized in that: The locking groove (10) comprises a first locking groove (16) and a second locking groove (17); the first locking groove (16) comprises an oblique axial groove (15), a first axial groove (18), a first circumferential groove (19), a second axial groove (20) and a second circumferential groove (21); the first circumferential groove (19) and the second circumferential groove (21) extend in opposite directions; the second locking groove (17) comprises a straight axial groove (22), a first axial groove (18), a first circumferential groove (19), a second axial groove (20) and a second circumferential groove (21); the straight axial groove (22) extends axially from the first axial groove (18); the oblique axial groove (15) extends circumferentially from the first axial groove (18) and then extends axially.

6. The circulating fluidized bed hood according to any one of claims 2 to 5, characterized in that: An air outlet (24) is provided on the side of the air duct (2), and a cover plate (25) is provided at the position of the air outlet (24). The cover plate (25) is hingedly mounted in a manner that it can rotate relative to the air outlet (24). The airflow in the air duct (2) can push the cover plate (25) to open the air outlet (24), and the airflow flowing from the outside of the air duct (2) to the inside of the air duct (2) can push the cover plate (25) to close the air outlet (24).

7. The circulating fluidized bed hood according to claim 6, characterized in that: The inner cavity (3) is provided with a guide plate (26) at the wind hole (4) so ​​as to guide the internal airflow to the position of the wind hole (4).

8. The circulating fluidized bed hood according to claim 7, characterized in that: A spiral blade (27) is provided between the guide plate (26) and the cover plate (25) and can guide the airflow into a spiral flow.

9. The circulating fluidized bed hood according to claim 8, characterized in that: The spiral blade (27), the guide plate (26) and the cover plate (25) are fixed on the same cylinder (28) to form an integrated guide structure (5).

10. The circulating fluidized bed hood according to claim 9, characterized in that: A floating cover (33) is provided on the base (7) to divide the inner cavity (3) into an upper cavity (31) and a lower cavity (32); the spiral blade (27), the guide plate (26) and the cover plate (25) are all located in the lower cavity (32); the pressure of the lower cavity (32) is greater than the pressure of the upper cavity (31) and when the pressure difference reaches a certain value, the floating cover (33) can be pushed upward.

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