Ventilation mechanism and opposed firing boiler layer secondary air volume simulation device

Abstract

The utility model discloses a ventilation mechanism and an opposed firing boiler layer secondary air volume simulation device, which relate to the field of air duct flow field optimization, and comprise a ventilation pipe, the ventilation pipe comprises a main air duct, a shunting air duct and a steering air duct between the main air duct and the shunting air duct, the output end of the shunting air duct is connected with a first layer air duct and a second layer air duct, and an equipartition part, and the equipartition component is fixedly connected with the ventilation pipe and comprises a plurality of flow guide plate groups and partition plates. The secondary air distribution device has the advantages that the secondary air distribution problem of the whole process of a secondary air system of a typical opposed firing boiler layer is considered, three sets of optimized assemblies are designed along the way, and the air distribution uniformity between the front wall and the rear wall of the typical opposed firing boiler and between secondary air channels of all layers can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of air duct flow field optimization, in particular to a ventilation mechanism and a secondary air volume simulation device for a counter-combustion boiler layer. Background Art

[0002] For boilers with front and rear wall counter-fired combustion, due to the special structure and layout of their secondary air ducts, the secondary air, after coming out of the air preheater and passing through the main air duct, needs to pass through the front and rear wall distribution wind boxes, the layer secondary air ducts, and then enter the layer secondary wind boxes. Since the front and rear wall distribution wind boxes and the layer secondary air ducts have very complex structures, the secondary air volume is unevenly distributed between the front and rear walls and between the wind boxes on each layer. Since it is difficult to accurately measure the online air volume, operators generally keep the layer damper opening the same, and assume that the air volume of each layer of the operating layer burner is the same. In fact, the problem of uneven distribution of the secondary air volume in the layers of counter-fired combustion boilers exists naturally. Although the boiler factory keeps the layer air duct and layer wind box structure and shape exactly the same during design, and the air inlet area of ​​the layer air duct and layer wind box is also exactly the same, due to the different positions of the layer air duct and layer wind box, and the complex flow field distribution at the layer air duct entrance, the secondary air volume between the front and rear walls and each layer is also different. The deviation between the layer air volume has an adverse effect on the combustion air volume distribution and coal powder burnout, resulting in poor boiler combustion conditions, low boiler thermal efficiency, and increased unit coal consumption.

[0003] At present, some scholars at home and abroad have studied the optimization of the secondary air duct flow field and found that the mass flow rate of the air at each outlet of the boiler secondary air duct is generally not equal in actual operation. Some scholars have also optimized certain secondary air ducts to improve the uniformity of air volume distribution. However, the current research objects are mainly the secondary air system of the four-corner tangential boiler or a specific structure. For the counter-fired boiler, the typical structure of the secondary air system from the air preheater outlet to the wind box (one-side) is shown in the attached figure. Figure 1 As shown in the figure, after the air preheater outlet, it first passes through the secondary main air duct turning elbow, and then part of the secondary air passes through the rear wall distribution wind box and the rear wall layer air duct, and the remaining secondary air continues to flow to the front wall distribution wind box and the front wall layer air duct. For the typical hedge combustion boiler layer secondary air volume equalization device, no relevant research has been seen so far. Utility Model Content

[0004] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and in the abstract and title of the utility model to avoid obscuring the purpose of this section, the abstract and the title of the utility model, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0005] In view of the above-mentioned existing technical problems, the present utility model is proposed.

[0006] The utility model aims to provide a ventilation mechanism, which aims to solve the problem that the mass flow rates of air at various outlets of a furnace secondary air duct are generally unequal.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a ventilation mechanism, which includes a ventilation pipe, which includes a main air duct, a diversion air duct and a turning air duct between the two. The output end of the diversion air duct is connected to the first layer air duct and the second layer air duct, and an equalizing component is fixedly connected to the ventilation pipe. The equalizing component includes several groups of guide plate groups and partition plates.

[0008] As a preferred solution of the ventilation mechanism of the present invention, the main air duct includes an air inlet section and an L section, one end of the L section is horizontally connected to the turning air duct, and the other end is vertically connected to the air inlet section, and the point where the L section is perpendicular to the air inlet section is set as the first inflection point.

[0009] As a preferred solution of the ventilation mechanism of the present invention, the turning air duct is arranged in a 90° arc shape.

[0010] As a preferred solution of the ventilation mechanism of the present invention, the diversion air duct includes a rear wall distribution air box and a front wall distribution air box, and the rear wall distribution air box is set as the second inflection point away from one end of the turning air duct.

[0011] As a preferred solution of the ventilation mechanism of the present invention, wherein: the first-layer air duct is connected to the rear wall distribution wind box, the front wall distribution wind box is connected to the second-layer air duct, the first-layer air duct includes four groups of pipes, and is divided into a1, a2, a3, and a4 from top to bottom, and the second-layer air duct includes four groups of pipes, and is divided into b1, b2, b3, and b4 from top to bottom.

[0012] As a preferred solution of the ventilation mechanism of the present invention, the guide plate group is arranged in an arc shape, and the guide plate group includes two groups of first guide plates arranged at the first inflection point and a second guide plate on the central path of the turning air duct.

[0013] As a preferred solution of the ventilation mechanism of the present invention, two groups of third guide plates are set at pipes a3 and a4 in the first-layer air duct, one group of third guide plates is set at pipe b2 in the second-layer air duct, and two groups of third guide plates are set at pipes b3 and b4.

[0014] As a preferred solution of the ventilation mechanism of the present invention, the partition plate is welded to the second inflection point, and one end of the partition plate away from the second inflection point is inclined toward the rear wall distribution air box.

[0015] The beneficial effects of the ventilation mechanism of the present invention are: taking into account the secondary air volume distribution problem of the entire process of the secondary air system of a typical counter-fired boiler, three groups of optimization components are designed along the process, which can improve the uniformity of air volume distribution between the front and rear walls of the typical counter-fired boiler and between the secondary air ducts of each layer.

[0016] Another object of the present invention is to provide a device for simulating the secondary air volume of a counter-fired boiler layer, which aims to solve the problems of inaccurate simulation calculation process and unclear algorithm of the secondary air volume of a counter-fired boiler layer.

[0017] In order to solve the above technical problems, the utility model also provides the following technical solutions: a secondary air volume simulation device for a counter-combustion boiler layer, which includes a ventilation mechanism; and a simulation device, wherein the simulation device includes a Fluent system, and the Fluent system can perform flow field calculations using numerical simulation software.

[0018] As an optimal solution for the secondary air volume simulation device of the hedge combustion boiler layer of the utility model, the Fluent system counts the air volume between the secondary air ducts of each layer and adjusts the positions and angles of the three groups of optimized components according to the improvement of the flow deviation until the flow deviation is less than 5%.

[0019] The beneficial effects of the counter-combustion boiler layer secondary air volume simulation device of the present invention are: the simulation calculation process of the counter-combustion boiler layer secondary air volume can be measured more accurately and the algorithm is clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without inventive work. Among them:

[0021] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0022] Figure 2 It is a top view of the utility model.

[0023] Figure 3 It is a top cross-sectional view of the ventilation duct in the utility model.

[0024] Figure 4 This is a cross-sectional view of the first layer of air duct in the present invention.

[0025] Figure 5 It is a cross-sectional view of the second-layer air duct in the present utility model.

[0026] Figure 6This is a distribution diagram of the flow field of the secondary air system in this utility model.

[0027] Figure 7 This is a distribution diagram of the flow field of the secondary air system after the equalizing device is set in the utility model. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below with reference to the accompanying drawings.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0031] Example 1

[0032] Reference Figure 1 , which is the first embodiment of the utility model, provides a ventilation mechanism, including a ventilation duct 100, which includes a main air duct 101, a branch air duct 102 and a turning air duct 103 therebetween, the output end of the branch air duct 102 is connected to a first-layer air duct 104 and a second-layer air duct 105, the main air duct 101 includes an air inlet section 101a and an L section 101b, one end of the L section 101b is horizontally connected to the turning air duct 103, and the other end is vertically connected to the air inlet section 101a, and the point where the L section 101b is perpendicular to the air inlet section 101a is set as a first inflection point A.

[0033] Furthermore, the turning air duct 103 is set to a 90° arc, and the diversion air duct 102 includes a rear wall distribution air box 102a and a front wall distribution air box 102b. The rear wall distribution air box 102a is set to a second inflection point B at one end away from the turning air duct 103.

[0034] Furthermore, the first-layer air duct 104 is connected to the rear wall distribution wind box 102a, and the front wall distribution wind box 102b is connected to the second-layer air duct 105. The first-layer air duct 104 includes four groups of pipes, and is divided into a1, a2, a3, and a4 from top to bottom. The second-layer air duct 105 includes four groups of pipes, and is divided into b1, b2, b3, and b4 from top to bottom.

[0035] Specifically, the experiment started with ventilation. Since the air inlet section 101a and the L section 101b are arranged vertically, the wind is buffered when it reaches the L section 101b after passing through the air inlet section 101a, so that the wind flow rate can enter the L section 101b more smoothly and evenly. When the wind passes through the L section, it can be affected by the curved side wall of the turning air duct 103 to buffer the wind speed at all times. After the wind passes through the curved side wall, it enters the diversion air duct 102. The diversion air duct 102 is provided with a rear wall distribution air box 102a and a front wall distribution air box 102b. The diversion air duct 102 between the rear wall distribution air box 102a and the front wall distribution air box 102b is set to be narrower, so that the wind is divided after passing through the rear wall distribution air box 102a to the first-layer air duct 104, and the remaining air volume reaches the second-layer air duct 105 after passing through the narrower section. The air volume always remains uniform.

[0036] Example 2

[0037] Reference Figures 1 to 4 , which is the second embodiment of the present utility model. Different from the previous embodiment, it also includes an equal distribution component 200, which is fixedly connected to the ventilation pipe 100. The equal distribution component 200 includes several groups of guide plate groups 201 and partition plates 202. The guide plate group 201 is arranged in an arc shape. The guide plate group 201 includes two groups of first guide plates 201a arranged at the first inflection point A and a second guide plate 201b on the central path of the turning air duct 103.

[0038] Furthermore, two groups of third guide plates 201c are provided at pipes a3 and a4 in the first-layer air duct 104, one group of third guide plates 201c is provided at pipe b2 in the second-layer air duct 105, and two groups of third guide plates 201c are provided at pipes b3 and b4. The partition plate 202 is welded to the second inflection point B, and the end of the partition plate 202 away from the second inflection point B is inclined toward the rear wall distribution air box 102a.

[0039] Specifically, the two groups of first guide plates 201a set at the first inflection point A are set in parallel, and the second guide plate 201b is set at a position on the central path of the turning air duct 103. The second guide plate 201b symmetrically divides the air volume. A partition plate 202 is set at the position of the second inflection point. The front end of the partition plate 202 is inclined toward the side of the rear wall distribution air box 102a, which can achieve the effect of guiding the air volume.

[0040] Specifically, there are two groups of third guide plates 201c set at pipes a3 and pipes a4, two groups of third guide plates 201c are attached to the upper half of pipe a3, two groups of third guide plates 201c are attached to the upper half of pipe a4, a third guide plate 201c is set at the bottom of pipe b2, and two groups of third guide plates 201c are set at pipes b3 and b4 and are set in the upper half of the pipes.

[0041] The flow field streamlines of the main air duct 101 and the branch air duct 102 are shown in FIG. Figure 6 From the calculation results, it can be seen that: due to the action of the second guide plate 201b at the turning point of the main air duct 101 into the air duct 103, the uniformity of the distribution of secondary air in the main air duct 101 is improved. Combined with the distribution wind box averaging plate, the problem of low air volume on the front wall can be improved; under the action of the guide component at the entrance of the layer air duct, the flow distribution of the secondary air changes when it enters the layer air duct through the distribution wind box.

[0042] The statistical results of air volume on each floor before and after optimization are shown in the following table:

[0043] Table 1: Statistics of secondary air volume in the lower layer of the original air duct layout

[0044] Location Front wall, kg / s Back wall, kg / s SOFA 31.67 32.35 upper layer 26.58 26.85 Middle level 25.02 28.67 Lower level 26.64 28.83

[0045] Table 2: Statistics of secondary air volume after optimization

[0046] Location Front wall, kg / s Back wall, kg / s SOFA 33.17 31.27 upper layer 26.75 27.03 Middle level 26.37 27.79 Lower level 26.94 27.33

[0047] The secondary air volume of the front wall layer has increased, which is 0.2% lower than the average value of the rear wall burner layer. The air volume of the middle layer of the front wall is 2.5% lower than the average secondary air volume, which is a significant improvement compared with before the change, which is conducive to uniform air distribution between the layer wind boxes.

[0048] Example 3

[0049] Reference Figures 1 to 4 This is the third embodiment of the present invention, further providing a device for simulating the secondary air flow rate of a counter-fired boiler layer. The device includes a simulation device 300, which includes a Fluent system. The Fluent system can perform flow field calculations using numerical simulation software. The Fluent system 301 calculates the air flow rate between the secondary air ducts on each layer and adjusts the positions and angles of three optimized components based on the improvement in flow deviation until the flow deviation is within 5%.

[0050] Specifically, the calculation method is as follows: 1. Create a 1:1 three-dimensional model based on the secondary air system design drawings, and use Fluent numerical simulation software to calculate the flow field and count the air volume between the secondary air ducts on each layer; 2. The main air duct turning elbow guide components are evenly arranged in the air duct, and the structure is composed of a 90° arc guide plate + an end straight plate. The end straight plate is parallel to the air duct wall. The secondary air first passes through the arc section to turn, and then passes through the end straight plate to ensure that the airflow direction is parallel to the air duct wall; 3. The air box equalizing plate is divided according to the air volume deviation between the front and rear walls. The design is based on the difference. If the front wall flow is low, the averaging plate will be biased toward the inner wall of the duct to guide part of the secondary air flowing to the rear wall to the front wall duct; 4. The guide assembly at the entrance of the duct is installed at the duct with low flow to guide more air in the distribution box to the duct with low flow; 5. After completing the above preliminary design, the flow field calculation is performed again using Fluent numerical simulation software to count the air volume between the secondary ducts of each layer. According to the improvement of the flow deviation, the position and angle of the three groups of optimized components are adjusted until the flow deviation is less than 5%.

[0051] It will be appreciated that in the development of any actual embodiment, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will, for those of ordinary skill having the benefit of this disclosure, be a routine undertaking of design, fabrication, and production without undue experimentation.

[0052] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, and all of these should be included in the scope of the claims of the present invention.

Claims

1. A ventilation mechanism, characterized in that: include, A ventilation duct (100) comprises a main air duct (101), a diverting air duct (102), and a diverting air duct (103) therebetween, wherein the output end of the diverting air duct (102) is connected to a first-layer air duct (104) and a second-layer air duct (105); The evenly dividing component (200) is fixedly connected to the ventilation pipe (100), and the evenly dividing component (200) includes a plurality of guide plate groups (201) and a partition plate (202).

2. The ventilation mechanism according to claim 1, wherein: The main air duct (101) comprises an air inlet section (101a) and an L section (101b); one end of the L section (101b) is horizontally connected to the turning air duct (103), and the other end is vertically connected to the air inlet section (101a); The point where the L section (101b) is perpendicular to the air inlet section (101a) is set as a first inflection point (A).

3. The ventilation mechanism according to claim 2, wherein: The turning air duct (103) is configured to be in a 90° arc shape.

4. The ventilation mechanism according to claim 3, wherein: The diversion air duct (102) comprises a rear wall distribution air box (102a) and a front wall distribution air box (102b), and the rear wall distribution air box (102a) is arranged at an end away from the turning air duct (103) as a second inflection point (B).

5. The ventilation mechanism according to claim 4, wherein: The first-layer air duct (104) is in communication with the rear wall distribution air box (102a), and the front wall distribution air box (102b) is in communication with the second-layer air duct (105); The first layer of air duct (104) includes four groups of pipes, which are divided into a1, a2, a3, and a4 from top to bottom; The second-layer air duct (105) includes four groups of pipes, which are divided into b1, b2, b3, and b4 from top to bottom.

6. The ventilation mechanism according to claim 5, wherein: The guide plate group (201) is arranged in an arc shape, and comprises two groups of first guide plates (201a) arranged at a first inflection point (A) and a second guide plate (201b) on a central path of the turning air duct (103).

7. The ventilation mechanism according to claim 6, wherein: Two sets of third guide plates (201c) are provided at both the pipe a3 and the pipe a4 in the first-layer air duct (104), one set of third guide plates (201c) is provided at the pipe b2 in the second-layer air duct (105), and two sets of third guide plates (201c) are provided at both the pipe b3 and the pipe b4.

8. The ventilation mechanism according to claim 7, wherein: The partition plate (202) is welded to the second inflection point (B), and one end of the partition plate (202) away from the second inflection point (B) is inclined toward the rear wall distribution air box (102a).

9. A device for simulating secondary air volume in a counter-fired boiler layer, characterized by: It comprises the ventilation mechanism according to any one of claims 1 to 8; and a simulation device (300), wherein the simulation device comprises a Fluent system, and the Fluent system can perform flow field calculations using numerical simulation software.

10. The device for simulating secondary air volume in a counter-fired boiler layer according to claim 9, characterized in that: The Fluent system (301) counts the air volume between the secondary air ducts of each layer and adjusts the positions and angles of the three groups of optimized components according to the improvement of the flow deviation until the flow deviation is less than 5%.

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