A device for improving flue gas uniformity in large-angle bend flow field of boiler

Abstract

The present invention discloses a device for improving the uniformity of flue gas in a large-angle bend flow field of a boiler, comprising a plurality of Y-shaped baffles, a plurality of obtuse-angle baffles and a plurality of arc-shaped baffles; the large-angle bend of the boiler comprises an inlet flue, a connecting flue and an outlet flue, the inlet flue is connected with an inlet on the left side of the connecting flue, and the outlet flue is connected with an outlet on the right side of the connecting flue, wherein each of the Y-shaped baffles, the obtuse-angle baffles and the arc-shaped baffles is located in the connecting flue and directly faces the outlet flue, and the device can effectively improve the uniformity of flue gas in the large-angle bend flow field of the boiler.

Description

Technical Field

[0001] The invention belongs to the technical field of boilers and relates to a device for improving the flue gas uniformity of a boiler large-angle bend flow field. Background Art

[0002] In the design of boiler structure, in order to facilitate the arrangement of heating surfaces, optimize heat transfer efficiency, and prevent serious local overheating, dust accumulation or wear, the requirements for flue gas uniformity are generally high. However, in the design of boiler structure, it is inevitable that there is a large angle flue structure. This structure causes a large velocity gradient of the flue gas after the turn, resulting in poor flue gas uniformity on the cross section, and sometimes even high-temperature flue gas sticking to the wall. If such a curved structure is not optimized, it will not only cause serious wall wear, but also make it impossible to arrange the heating surface reasonably. The actual operation of the boiler will deviate greatly from the theoretical design.

[0003] For the optimization of flow field in large-angle bends, dense grid plates, guide plates or air distribution plates are generally used to achieve better flow uniformity. However, due to the huge amount of materials used and the inability to withstand high temperatures, they are only used in the low-temperature part of the boiler, such as primary and secondary air, and the flue gas at the rear of the air preheater. In the high-temperature part of the boiler, such as the furnace outlet, the above structure is difficult to apply due to the very high temperature. Therefore, the optimization method of adding a flame deflection angle is generally used, but the optimization effect is very limited. Therefore, for large-angle bends in boilers, especially for the high-temperature part of the furnace outlet, there is still a lack of a systematic flow field uniformity optimization method that simultaneously considers flow field uniformity, particle deposition, and engineering feasibility. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a device for improving the uniformity of flue gas in a large-angle bend flow field of a boiler, which can effectively improve the uniformity of flue gas in a large-angle bend flow field of a boiler.

[0005] To achieve the above-mentioned purpose, the device for improving the flue gas uniformity of the boiler large-angle bend flow field of the present invention comprises a plurality of Y-shaped baffles, a plurality of obtuse-angle baffles and a plurality of arc-shaped baffles;

[0006] The large-angle bend of the boiler includes an inlet flue, a connecting flue and an outlet flue. The inlet flue is connected to the entrance on the left side of the connecting flue, and the outlet flue is connected to the outlet on the right side of the connecting flue. Among them, each Y-shaped baffle, obtuse-angle baffle and arc baffle is located in the connecting flue and directly faces the outlet flue.

[0007] A left chamfer and a right chamfer are respectively arranged at the positions connecting the two corners of the flue bottom, and a side wall deflection angle is arranged on the side of the flue, wherein the side wall deflection angle is located just above the right chamfer.

[0008] A flame deflection angle is arranged at the entrance position connected to the flue.

[0009] The obtuse-angle baffle is composed of two first baffles, wherein the ends of the two first baffles are separated, and the angle between the two first baffles is greater than 90° and less than or equal to 185°.

[0010] The Y-type baffle consists of a second baffle, a third baffle and a fourth baffle, wherein the second baffle is located below the third baffle and the fourth baffle, and the angle between the second baffle and the third baffle is 90°-175°, the angle between the fourth baffle and the third baffle is greater than 0° and less than 85°, and the second baffle, the third baffle and the fourth baffle are separated from each other, and the length of the fourth baffle is smaller than the second baffle and the third baffle.

[0011] The arc-shaped baffle is composed of a fifth baffle alone, and the fifth baffle is an arc-shaped long plate with a central angle of 30-160 degrees.

[0012] The first baffle, the second baffle, the third baffle, the fourth baffle and the fifth baffle are all provided with tube screens inside, wherein the tube screens are connected with a collecting box, and the outer walls of the first baffle, the second baffle, the third baffle, the fourth baffle and the fifth baffle are all provided with a wear-resistant castable layer.

[0013] The outlet connected to the flue is divided into N equally divided points, and an obtuse-angle baffle, a Y-shaped baffle or an arc-shaped baffle is arranged at each equally divided point.

[0014] The side wall baffle angle is arranged on the boiler furnace wall, wherein the angle of the side wall baffle angle is 90°-170°, and the position of the side wall baffle angle is an arc-shaped structure or a boss-shaped structure.

[0015] The present invention has the following beneficial effects:

[0016] During specific operation, the device for improving flue gas uniformity in the large-angle bend flow field of the boiler described in the present invention adds obtuse-angle baffles, Y-shaped baffles, arc-shaped baffles, side wall baffle angles, left chamfers, right chamfers and flame deflection angles in the connecting flue to significantly improve the flow field, and has the characteristics of high flow field uniformity, less particle deposition, and less wall wear. It greatly increases the uniformity of the flue flow field and significantly reduces the relative standard deviation of the normal velocity of the outlet flow field. At the same time, it eliminates the situation of high-temperature flue gas adhering to the wall and reduces the degree of wall wear. In addition, the design of chamfers and Y-shaped baffles greatly reduces the dead zone area of ​​the secondary flow in the connecting flue, which can effectively reduce particle deposition. It has a simple structure, good engineering feasibility, little effect on flue gas resistance, and has no effect on the structure and heating surface layout of the original inlet and outlet flues, laying a foundation for the good heat transfer efficiency and service life of the boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1a It is a structural schematic diagram of the present invention;

[0018] Figure 1b is a side view of the present invention;

[0019] Figure 2 is a schematic diagram of the internal structure of the first baffle;

[0020] Figure 3a It is a structural schematic diagram of embodiment 1;

[0021] Figure 3b It is a side view of the first embodiment;

[0022] Figure 4a It is a structural schematic diagram of the second embodiment;

[0023] Figure 4b It is a side view of the first embodiment;

[0024] Figure 5 This is a schematic diagram of the structure of the third embodiment.

[0025] Among them, 1 is the inlet flue, 2 is the connecting flue, 3 is the outlet flue, 4 is the obtuse-angle baffle, 5 is the arc-shaped baffle, 6 is the Y-type baffle, 7 is the left chamfer, 8 is the right chamfer, 9 is the side wall baffle angle, 10 is the flame baffle angle, 11 is the header, 12 is the tube screen, and 13 is the wear-resistant castable layer. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0027] refer to Figure 1a , Figure 1b and Figure 2 The device for improving the flue gas uniformity of the large-angle bend flow field of the boiler described in the present invention includes a plurality of Y-shaped baffles 6, a plurality of obtuse-angle baffles 4 and a plurality of arc-shaped baffles 5; the large-angle bend of the boiler includes an inlet flue 1, a connecting flue 2 and an outlet flue 3, the inlet flue 1 is connected to the inlet on the left side of the connecting flue 2, and the outlet flue 3 is connected to the outlet on the right side of the connecting flue 2, wherein each Y-shaped baffle 6, obtuse-angle baffle 4 and arc-shaped baffle 5 is located in the connecting flue 2 and directly opposite the outlet flue 3.

[0028] A left chamfer 7 and a right chamfer 8 are respectively arranged at the two corners of the bottom of the connecting flue 2, and a side wall deflection corner 9 is arranged on the side of the connecting flue 2, wherein the side wall deflection corner 9 is located directly above the right chamfer 8; a flame deflection corner 10 is arranged at the entrance of the connecting flue 2.

[0029] The obtuse-angle baffle 4 is composed of two first baffles, wherein the ends of the two first baffles are separated, and the angle between the two first baffles is greater than 90° and less than or equal to 185°; the Y-shaped baffle 6 is composed of a second baffle, a third baffle and a fourth baffle, wherein the second baffle is located below the third baffle and the fourth baffle, and the angle between the second baffle and the third baffle is 90°-175°, the angle between the fourth baffle and the third baffle is greater than 0° and less than 85°, and the second baffle, the third baffle and the fourth baffle are separated from each other, and the length of the fourth baffle is less than that of the second baffle and the third baffle. The arc baffle 5 is composed of a fifth baffle alone, and the fifth baffle is a long arc-shaped plate with a central angle of 30-160°.

[0030] The first baffle, the second baffle, the third baffle, the fourth baffle and the fifth baffle are all provided with tube screens 12, wherein the tube screens 12 are connected to the collecting box 11, and the outer walls of the first baffle, the second baffle, the third baffle, the fourth baffle and the fifth baffle are all provided with wear-resistant castable layers 13.

[0031] The outlet connected to the flue 2 is divided into N equally divided points, each of which is provided with an obtuse-angled baffle 4, an arc-shaped baffle 5 or a Y-shaped baffle 6; the side wall baffle angle 9 is provided on the boiler furnace wall, wherein the angle of the side wall baffle angle 9 is 90°-170°, and the position of the angle of the side wall baffle angle 9 is an arc-shaped structure or a boss-shaped structure.

[0032] Embodiment 1

[0033] refer to Figure 3a and Figure 3b In this embodiment, the connecting flue 2 is located at the bottom and also serves as an ash hopper, dividing the connecting flue 2 into three equal parts, a group of obtuse-angle baffles 4 are arranged at the left third, and a group of Y-shaped baffles 6 are arranged at the right third.

[0034] The width of the outlet flue 3 is defined as 100 units, and the obtuse-angle baffle 4 on the left side is composed of two first baffles with a length of 20 units. The angle between the two first baffles is set to 110°, and they do not touch each other. The length of the second baffle and the third baffle is 30 units, and the angle is 160 degrees; the length of the fourth baffle is 10 units, and it forms an angle of 20° with the vertical direction.

[0035] Chamfers are added at the two corners of the bottom connecting the flue 2, wherein the left chamfer 7 is 25 units wide and has an angle of 45° with the horizontal direction; the right chamfer 8 is 25 units wide and has an angle of 50° with the horizontal direction. A side wall deflection angle 9 is set on the upper wall of the right chamfer 8. As part of the boiler furnace wall, the angle between the two sides is 130°. The side length of the side wall deflection angle 9 is 10 units, and the tip adopts an arc structure, and no flame deflection angle 10 is set.

[0036] According to calculations, this embodiment can reduce the relative standard deviation of the normal velocity of the outlet flow field by about 76%, greatly improving the uniformity of the flow field, while the flue resistance increases by only about 4%.

[0037] Embodiment 2

[0038] refer to Figure 4a and Figure 4b In this embodiment, the connecting flue 2 is located at the top and is divided into four equal parts. A group of obtuse-angle baffles 4 are arranged at the left quarter, and two groups of Y-shaped baffles 6 are arranged at the middle half and the right quarter.

[0039] The width of the outflow flue 3 is defined as 100 units, and the obtuse-angle baffle 4 on the left side is composed of two first baffles with a length of 15 units. The angle between the two first baffles is 160 degrees, and they do not touch each other. The length of the second baffle and the third baffle is 25 units, and the angle is 170 degrees; the length of the fourth baffle is 10 units, and it forms an angle of 20 degrees with the vertical direction.

[0040] At the same time, a right chamfer 8 is added at the upper right corner of the connecting flue 2, with a width of 25 units and an angle of 50° with the horizontal direction. A side wall deflection angle 9 is set at the wall below the right chamfer 8. As a part of the boiler wall, the angle between the two sides is 130°, the side length of the side wall deflection angle 9 is 10 units, and the tip adopts an arc structure. A flame deflection angle 10 is set at the entrance of the connecting flue 2, with an angle between the two sides of 110° and a side length of 20 units. No left chamfer 7 is set.

[0041] According to calculations, this embodiment can reduce the relative standard deviation of the normal velocity of the outlet flow field by about 80%, greatly improving the uniformity of the flow field, while the flue resistance only increases by about 5%.

[0042] Embodiment 3

[0043] refer to Figure 5 In this embodiment, the connecting flue 2 is located at the bottom and also serves as an ash hopper. The connecting flue 2 is divided into five equal parts, and a group of arc-shaped baffles 5 are provided at each equal part, with a total of 4 groups of arc-shaped baffles.

[0044] Define the width of the outlet flue 3 as 100 units, then the first group of arc-shaped baffles 5 on the left are arc-shaped long plates with a radius of 15 units and a central angle of 85 degrees, the second group of arc-shaped baffles 5 on the left are arc-shaped long plates with a radius of 22 units and a central angle of 90 degrees, the third group of arc-shaped baffles 5 on the left are arc-shaped long plates with a radius of 27 units and a central angle of 85 degrees, and the fourth group of arc-shaped baffles 5 on the left are arc-shaped long plates with a radius of 35 units and a central angle of 90 degrees.

[0045] Chamfers are added at the two corners of the bottom connecting the flue 2, wherein the left chamfer 7 is 25 units wide and has an angle of 45° with the horizontal direction; the right chamfer 8 is 25 units wide and has an angle of 50° with the horizontal direction. A side wall deflection angle 9 is set on the upper wall of the right chamfer 8. As part of the boiler furnace wall, the angle between the two sides is 130°. The side length of the side wall deflection angle 9 is 10 units, and the tip adopts an arc structure, and no flame deflection angle 10 is set.

[0046] According to calculations, this embodiment can reduce the relative standard deviation of the normal velocity of the outlet flow field by about 87%, greatly improving the uniformity of the flow field, while the flue resistance increases by only about 3%.

Claims

1. A device for improving the flue gas uniformity of a boiler with a large angle bend flow field, characterized in that: It comprises a plurality of Y-shaped baffles (6), a plurality of obtuse-angle baffles (4) and a plurality of arc-shaped baffles (5); The boiler large-angle bend comprises an inlet flue (1), a connecting flue (2) and an outlet flue (3), wherein the inlet flue (1) is connected to an inlet on the left side of the connecting flue (2), and the outlet flue (3) is connected to an outlet on the right side of the connecting flue (2), wherein each Y-shaped baffle (6), obtuse-angle baffle (4) and arc-shaped baffle (5) are located in the connecting flue (2) and face the outlet flue (3); A left chamfer (7) and a right chamfer (8) are respectively arranged at the two corners of the bottom of the connecting flue (2), and a side wall deflection corner (9) is arranged on the side of the connecting flue (2), wherein the side wall deflection corner (9) is located directly above the right chamfer (8); A flame deflection angle (10) is provided at the entrance position connected to the flue (2); The obtuse-angle baffle (4) is composed of two first baffles, wherein the ends of the two first baffles are separated, and the angle between the two first baffles is greater than or equal to 90° and less than or equal to 175°; The Y-shaped baffle (6) is composed of a second baffle, a third baffle and a fourth baffle, wherein the second baffle is located below the third baffle and the fourth baffle, and the angle between the second baffle and the third baffle is 90°-175°, the angle between the fourth baffle and the third baffle is greater than 0° and less than 85°, and the second baffle, the third baffle and the fourth baffle are separated from each other, and the length of the fourth baffle is less than that of the second baffle and the third baffle; The arc-shaped baffle (5) is composed of a fifth baffle alone, and the fifth baffle is an arc-shaped long plate with a central angle of 30-160°; The first baffle, the second baffle, the third baffle, the fourth baffle and the fifth baffle are all provided with tube panels (12) inside, wherein the tube panels (12) are connected to a header (11), and the outer walls of the first baffle, the second baffle, the third baffle and the fourth baffle are all provided with a wear-resistant castable layer (13); The outlet connected to the flue (2) is divided into N equally divided points, and each equally divided point is provided with an obtuse-angle baffle (4), a Y-shaped baffle (6) or an arc-shaped baffle (5); The side wall baffle angle (9) is arranged on the boiler furnace wall, wherein the angle of the side wall baffle angle (9) is 90°-170°, and the position of the side wall baffle angle (9) is an arc-shaped structure or a boss-shaped structure.

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