Secondary air flow speed adjusting structure and fluidized bed boiler thereof

Abstract

The utility model belongs to the technical field of boiler air and smoke systems, and particularly relates to a secondary air flow speed adjusting structure and a fluidized bed boiler thereof. The structure comprises a main air box suitable for generating secondary air; one end of each shunting air pipe is connected with the air outlet of the main air box; wherein at least one shunting air pipe is provided with an air adjusting door; and when the main air bellow runs at low load, the air adjusting door closes the corresponding shunting air pipe, so that the air volume of the normally-open shunting air pipe is increased. The main air bellow is connected with the multiple flow dividing air pipes to achieve flow dividing of secondary air, the air adjusting door is installed on at least one flow dividing air pipe, when the main air bellow is in a low load state, the corresponding flow dividing air pipe is closed to improve the air volume in the remaining flow dividing air pipes, and it is ensured that the air speed can reach the preset value under the low load state.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the boiler wind and smoke system technical field, concretely relates to secondary air flow velocity adjusting structure and fluidized bed boiler. BACKGROUND

[0002] According to the oxygen distribution rule in the circulating fluidized bed boiler hearth, the single layer is arranged secondary air nozzle, and the nozzle adopts the design concept of high air speed and large momentum;The inclined section of the secondary air pipe is designed into a long "big head" shape, and the secondary air can form an accelerated state in the inclined section, so that the secondary air has high stiffness. Can effectively reduce the fly ash combustible, improve the boiler thermal efficiency.

[0003] When the boiler is running at low load, the required secondary air volume will be reduced, and in the case of reduced secondary air volume, it is impossible to ensure that the secondary air also has high wind speed, the wind speed of the secondary air decreases, the penetration ability weakens, which will lead to the increase of fly ash combustible, and further lead to the decrease of boiler thermal efficiency.

[0004] Therefore, it is urgent to design a secondary air flow velocity adjusting structure and fluidized bed boiler to solve the above-mentioned technical problem of secondary air wind speed decrease at low load of the boiler.

[0005] It should be noted that the above information disclosed in the background section of the present application is only used to understand the background of the present application, and therefore, it can contain information which does not constitute prior art. CONTENT OF THE UTILITY MODEL

[0006] The present application provides at least a secondary air flow velocity adjusting structure and fluidized bed boiler.

[0007] In the first aspect, the present application provides a secondary air flow velocity adjusting structure, comprising: a main air box adapted to generate secondary air;

[0008] A plurality of shunt air pipes, one end of which is connected with the gas outlet of the main air box;

[0009] Among them, at least one shunt air pipe is provided with an air regulating door;

[0010] And when the main air box is running at low load, the air regulating door closes the corresponding shunt air pipe, so that the shunt air pipe which is always open increases the air volume.

[0011] In an alternative embodiment, an expansion joint is installed on the shunt air pipe.

[0012] In an alternative embodiment, the cross-sectional area of the end of the shunt air pipe away from the main air box is smaller than the cross-sectional area of the end close to the main air box.

[0013] In a second aspect, the present disclosure provides a secondary air flow rate adjusting structure, comprising: a main air box adapted to generate secondary air;

[0014] two branch air pipes, one end of each of which is connected to an air outlet of the main air box;

[0015] wherein, one of the branch air pipes is provided with an air adjusting door;

[0016] and when the main air box is in a low load operation mode, the air adjusting door is closed to the corresponding branch air pipe, so that the air volume of the other branch air pipe is increased;

[0017] an expansion joint is installed on the branch air pipe;

[0018] a cross-sectional area of the end of the branch air pipe away from the main air box is smaller than that of the end of the branch air pipe close to the main air box.

[0019] In an optional embodiment, the two branch air pipes are arranged in parallel.

[0020] In an optional embodiment, the vertical distance between the two ends of the branch air pipe away from the main air box is 450 mm.

[0021] In a third aspect, the present disclosure provides a fluidized bed boiler, comprising the secondary air flow rate adjusting structure as described above, and the fluidized bed boiler further comprises a furnace;

[0022] a plurality of the secondary air flow rate adjusting structures are installed on the side wall of the furnace in a circumferential direction.

[0023] In an optional embodiment, the outer wall of the furnace is provided with a plurality of air inlets;

[0024] the end of the branch air pipe away from the main air box is inserted into the air inlet.

[0025] In an optional embodiment, the outer side of the air inlet is provided with a sealing shell;

[0026] the sealing shell covers the branch air pipe.

[0027] The present utility model has the advantages that the main air box is connected with a plurality of branch air pipes to realize the distribution of secondary air, and an air adjusting door is installed on at least one of the branch air pipes, so that when the main air box is in a low load operation mode, the corresponding branch air pipe is closed to increase the air volume in the remaining branch air pipe and ensure that the air speed reaches the preset value.

[0028] The other features and advantages of the present application will be more apparent from the following description, and will be partially apparent from the description, or will be learned through implementation of the present application. The objects and other advantages of the present application are achieved and obtained by the structure specifically indicated in the description, claims, and drawings.

[0029] In order to make the above objects, features and advantages of the present application more apparent and easy to understand, the following preferred embodiments are specifically described below, and the accompanying drawings are described in detail as follows. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0031] Figure 1 A structural schematic diagram of a secondary air flow rate adjusting structure provided by the embodiment of the present disclosure;

[0032] Figure 2 A structural schematic diagram of a fluidized bed boiler provided by the embodiment of the present disclosure.

[0033] In the drawings:

[0034] 1, main air box; 2, shunt air pipe; 3, air regulating door; 4, expansion joint;

[0035] 5, furnace; 6, sealing shell. DETAILED DESCRIPTION

[0036] In order to make the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the present application will be described clearly and completely in combination with the drawings. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0037] It is found through research that when the boiler is running at low load, the required secondary air quantity will be reduced. In the case of reduced secondary air quantity, it is impossible to ensure that the secondary air also has high air speed. The air speed of the secondary air decreases, the penetration ability is weakened, which will lead to the rising of fly ash combustibles, and further lead to the reduction of boiler thermal efficiency.

[0038] The above-mentioned defects are the results of the inventors' practice and careful research, and thus the discovery process of the above-mentioned problems and the solutions proposed by the present disclosure to solve the above-mentioned problems should be the contributions of the inventors to the present disclosure.

[0039] Some embodiments of the present application will be described in detail with reference to the drawings. In the case of no conflict, the embodiments described below and the features in the embodiments can be combined with each other. In addition, in the drawings, the thickness of the components can be exaggerated or reduced for effective description of the technical content.

[0040] It should be noted that similar reference numerals and letters represent similar items in the following drawings, and thus once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

[0041] Based on the above research, with reference to Figure 1 The secondary air flow speed adjusting structure provided by the embodiments of the present disclosure comprises a main air box 1 adapted to generate secondary air. In order to ensure that the combustible content of fly ash entering the furnace 5 is maintained at a preset level and the thermal efficiency of the boiler is maintained stable, the secondary air speed entering the furnace 5 should be maintained at 90 m / s or above. However, when the boiler is in a low load state, the secondary air volume generated by the main air box 1 will be reduced to below 90 m / s, so that under the same conditions, the secondary air speed entering the furnace 5 will also decrease, and its penetration ability will decrease significantly, so that air and materials cannot be fully mixed and combusted, ultimately leading to an increase in the combustible content of fly ash and a decrease in the thermal efficiency of the boiler.

[0042] Therefore, with reference to Figure 1 In at least one embodiment, the secondary air flow speed adjusting structure comprises a plurality of shunt air pipes 2, one end of each shunt air pipe 2 is connected to the air outlet of the main air box 1, and at least one shunt air pipe 2 is provided with an air adjusting door 3, which can be used to control the opening degree and opening and closing of the corresponding shunt air pipe 2. The shunt air pipe 2 is provided with an expansion joint 4 to compensate for the thermal expansion difference of the shunt air pipe 2, reduce the axial load, and avoid damage to the shunt air pipe 2.

[0043] In some embodiments, with reference to Figure 1 The number of shunt air pipes 2 is set to two, and one shunt air pipe 2 is provided with an air adjusting door 3, and the other is in a normally open state. Through the above setting, when the main air box 1 is in a low load state, the air adjusting door 3 closes the corresponding shunt air pipe 2, so that the air volume of the normally open shunt air pipe 2 increases, and thus the air volume in the normally open shunt air pipe 2 is maintained at the air volume under the normal load state, and thus the air speed in the normally open shunt air pipe 2 is maintained at 90 m / s or above.

[0044] In some embodiments, with reference to Figure 1The cross-sectional area of the branch air duct 2 at the end far from the main air box 1 is smaller than the cross-sectional area at the end close to the main air box 1. That is, the branch air duct 2 is arranged in a "size head" shape, so that the speed of the secondary air increases when the secondary air flows from the "big head" to the "small head".

[0045] In at least one embodiment, referring to Figure 1 The number of the branch air duct 2 is two, and the two branch air ducts 2 are arranged in parallel, and the vertical distance between the two ends of the branch air duct 2 far from the main air box 1 is 450 mm. Through the above arrangement, the air direction of the branch air duct 2 is consistent, and the two branch air ducts 2 are spaced apart in the vertical direction, so that the secondary air blown by the two branch air ducts 2 does not interfere with each other.

[0046] The disclosure also provides a fluidized bed boiler, referring to Figure 2 The fluidized bed boiler further comprises a hearth 5, and a plurality of secondary air flow rate adjustment structures are installed on the side wall of the hearth 5 in the circumferential direction. The secondary air is delivered into the hearth 5 by the secondary air flow rate adjustment structures at different positions, so as to ensure sufficient supply of secondary air in the hearth 5.

[0047] In some embodiments, referring to Figure 2 The outer wall of the hearth 5 is provided with a plurality of air inlets, and the end of the branch air duct 2 far from the main air box 1 is inserted into the air inlet.

[0048] In some embodiments, referring to Figure 2 The outer side of the air inlet is provided with a sealing shell 6, and the sealing shell 6 covers the branch air duct 2. The sealing shell 6 is used to seal the connection between the branch air duct 2 and the air inlet of the hearth 5, so as to avoid leakage of the secondary air.

[0049] In the several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are only illustrative, for example, the division of units is only a logical function division, and in actual implementation, another division mode can be used, and for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. Based on the above ideal embodiments of the present application, through the above description, relevant personnel can make various changes and modifications without departing from the scope of the technical idea of the present application. The technical scope of the present application is not limited to the content in the specification, and must be determined according to the scope of the claims.

Claims

1. A secondary air flow rate adjusting structure characterized by comprising: The secondary air flow speed adjusting structure comprises a main air box (1) adapted to generate secondary air; a plurality of branch air pipes (2) having one end connected with the air outlet of the main air box (1); wherein at least one of the branch air pipes (2) is provided with an air regulating door (3); and when the main air box (1) is in low load operation, the air regulating door (3) is closed to the corresponding branch air pipe (2) so as to increase the air flow of the normally open branch air pipe (2).

2. The secondary air flow speed adjusting structure according to claim 1, wherein the branch air pipe (2) is provided with an expansion joint (4).

3. The secondary air flow speed adjusting structure according to claim 1, wherein the cross-sectional area of the end of the branch air pipe (2) away from the main air box (1) is smaller than that of the end close to the main air box (1). The secondary air flow speed adjusting structure comprises a main air box (1) adapted to generate secondary air; two branch air pipes (2) having one end connected with the air outlet of the main air box (1); wherein one of the branch air pipes (2) is provided with an air regulating door (3); and when the main air box (1) is in low load operation, the air regulating door (3) is closed to the corresponding branch air pipe (2) so as to increase the air flow of the other branch air pipe (2); the branch air pipe (2) is provided with an expansion joint (4); and the cross-sectional area of the end of the branch air pipe (2) away from the main air box (1) is smaller than that of the end close to the main air box (1).

5. The secondary air flow speed adjusting structure according to claim 4, wherein the two branch air pipes (2) are arranged in parallel.

6. The secondary air flow speed adjusting structure according to claim 4, wherein the vertical distance of the ends of the two branch air pipes (2) away from the main air box (1) is 450 mm. The fluidized bed boiler comprises the secondary air flow speed adjusting structure according to any one of claims 4-6, and further comprises a furnace (5); A plurality of the secondary air flow speed adjusting structures are arranged on the side wall of the furnace (5) in a circumferential direction.

8. The fluidized bed boiler according to claim 7, wherein the outer wall of the furnace (5) is provided with a plurality of air inlets; and the end of the branch air pipe (2) away from the main air box (1) is inserted into the air inlet.

4. A secondary air flow rate adjusting structure characterized by comprising:

9. The fluidized bed boiler according to claim 8, wherein the outer side of the air inlet is provided with a sealing cover (6); and the sealing cover (6) covers the branch air pipe (2). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 7. A fluidized bed boiler, characterized in that ​ ​ ​ ​ ​ ​ ​ ​

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