Dry powder spray gun for desulfurization and catalytic cracking device

Abstract

The utility model provides a dry powder spray gun for desulfurization and a catalytic cracking device, and relates to the technical field of flue gas desulfurization. One end of the spray gun body is provided with an alkaline dry powder inlet, and the other end of the spray gun body is of a curved surface structure. A plurality of circulation hole assemblies are arranged on the side wall of the spray gun body and arranged at intervals in the axial direction of the spray gun body. Each circulation hole assembly comprises two circulation holes, and the two circulation holes are symmetrically formed in the side wall of the spray gun body. The curved surface structure is provided with an end circulation hole, the two ends of the end circulation hole extend to the side wall of the spray gun body correspondingly, and the two ends of the end circulation hole are symmetrically arranged on the side wall of the spray gun body. The alkaline dry powder is uniformly distributed on the section of the flue, so that the alkaline dry powder can be more uniformly dispersed in the flue, and the contact area with to-be-treated flue gas is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas desulfurization, in particular to a dry powder spray gun for desulfurization and a catalytic cracking device. Background Art

[0002] The catalytic cracking unit is an important heavy oil lightening equipment in the oil refining enterprise. During the operation of the catalytic cracking unit, the flue gas generated by the burning of the regenerator will pollute the atmosphere. The main pollutants include SO x 、NO x and particulate matter, etc.

[0003] Wet desulfurization is a widely used flue gas purification technology for catalytic cracking. When the SO3 concentration in the flue gas is high, flue gas purification equipment using wet desulfurization will experience secondary problems such as blue smoke plume and equipment corrosion.

[0004] The key to solving the above problems lies in removing SO3. The main method of removing SO3 at present is to use a dry powder spray gun to inject alkaline dry powder into the flue, so that the alkaline dry powder reacts chemically with SO3 in the flue gas to produce solid salt particles. The particles are then removed using dust removal equipment, thereby reducing aerosol emissions and eliminating the blue smoke phenomenon.

[0005] In the prior art, dry powder spray guns use a method of spraying along the direction of flue gas flow. Due to the fast flue gas flow rate and large gas volume, the diffusion of alkaline dry powder is poor, the alkaline dry powder is unevenly distributed in the flue, and the contact between flue gas and alkaline dry powder is uneven. Utility Model Content

[0006] The purpose of the utility model is to provide a dry powder spray gun for desulfurization, so as to solve the technical problem of uneven distribution of alkaline dry powder in the flue in the prior art.

[0007] The dry powder spray gun for desulfurization provided by the utility model comprises a spray gun main body;

[0008] One end of the spray gun body is provided with an alkaline dry powder inlet, and the other end of the spray gun body is a curved surface structure;

[0009] The side wall of the spray gun body is provided with a plurality of flow hole assemblies, and the plurality of flow hole assemblies are spaced apart along the axial direction of the spray gun body;

[0010] Each group of the flow hole assembly includes two flow holes, and the two flow holes are symmetrically arranged on the side wall of the spray gun body;

[0011] The curved surface structure is provided with an end flow hole, both ends of the end flow hole respectively extend to the side wall of the spray gun body, and the two ends of the end flow hole are symmetrically arranged on the side wall of the spray gun body.

[0012] Furthermore, the number of the flow hole assemblies is 3 to 5 groups.

[0013] Furthermore, the widths of the plurality of flow holes are the same;

[0014] Along the axial direction of the spray gun body and in a direction from the alkaline dry powder inlet toward the curved surface structure, the lengths of the plurality of flow holes increase sequentially.

[0015] Furthermore, along the axial direction of the spray gun body, the length of the flow holes close to the alkaline dry powder inlet among the multiple flow holes is 20mm-30mm, the width of the flow holes close to the alkaline dry powder inlet among the multiple flow holes is 5mm-8mm, and the length of the multiple flow holes increases by 10mm successively.

[0016] Furthermore, the length of the end circulation hole is 100 mm to 150 mm, and the width of the end circulation hole is 20 mm to 30 mm.

[0017] Furthermore, the desulfurization dry powder spray gun further includes a guide plate;

[0018] The guide plate includes a first plate body and a second plate body, the first plate body and the second plate body are vertically arranged, and the first plate body and the second plate body are fixedly connected;

[0019] The first plate is connected to the inner side wall of the spray gun body, and the second plate is arranged opposite to the flow hole.

[0020] Furthermore, the first plate body and the second plate body transition smoothly.

[0021] Furthermore, a fixing flange is provided on the outer side wall of the spray gun body.

[0022] Furthermore, a connecting flange is provided on the outer edge of the alkaline dry powder inlet.

[0023] The purpose of the utility model is also to provide a catalytic cracking device, including a flue and a dry powder spray gun for desulfurization provided by the utility model;

[0024] The spray gun body extends into the flue, the spray gun body is connected to the side wall of the flue, and the axial direction of the spray gun body is perpendicular to the flue gas flow direction.

[0025] The dry powder spray gun for desulfurization provided by the present invention includes a spray gun body; an alkaline dry powder inlet is provided at one end of the spray gun body, and the other end of the spray gun body is a curved surface structure; a plurality of groups of flow hole assemblies are provided on the side wall of the spray gun body, and the plurality of groups of flow hole assemblies are arranged at intervals along the axial direction of the spray gun body; each group of the flow hole assemblies includes two flow holes, and the two flow holes are symmetrically arranged on the side wall of the spray gun body; the curved surface structure is provided with an end flow hole, and the two ends of the end flow hole respectively extend to the side wall of the spray gun body, and the two ends of the end flow hole are symmetrically arranged on the side wall of the spray gun body. Driven by high-pressure air, alkaline dry powder enters the spray gun body through the alkaline dry powder inlet. Inside the spray gun body, the alkaline dry powder is divided into multiple streams, which are ejected into the flue through multiple flow holes and the end flow hole. Because the multiple flow hole assemblies are spaced apart along the axial direction of the spray gun body, and each flow hole assembly includes two flow holes symmetrically arranged on the side wall of the spray gun body, the multiple flow holes are distributed more evenly within the flue cross-section, enabling the alkaline dry powder to be more evenly distributed across the flue cross-section, thereby achieving more uniform dispersion within the flue and increasing the contact area with the flue gas to be treated. The alkaline dry powder flowing out of the end flow hole is distributed in a fan-shaped pattern, allowing the alkaline dry powder to more comprehensively cover the entire flue cross-section, fully contacting the flue gas and increasing the contact area between the alkaline dry powder and the flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic structural diagram of a dry powder spray gun for desulfurization provided by an embodiment of the utility model;

[0028] Figure 2 This is a structural schematic diagram of a guide plate of a dry powder spray gun for desulfurization provided by an embodiment of the utility model;

[0029] Figure 3 This is a velocity distribution cloud diagram of a dry powder spray gun for desulfurization in a flue cross section provided by an embodiment of the present utility model;

[0030] Figure 4 This is a velocity vector distribution diagram of a dry powder spray gun for desulfurization in a flue cross section provided by an embodiment of the utility model.

[0031] Icons: 1-spray gun body; 2-alkaline dry powder inlet; 3-connecting flange; 4-fixing flange; 5-first flow hole; 6-second flow hole; 7-third flow hole; 8-end flow hole; 9-guide plate; 91-first plate; 92-second plate. DETAILED DESCRIPTION

[0032] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0033] The utility model provides a dry powder spray gun for desulfurization and a catalytic cracking device. A plurality of embodiments are given below to describe in detail the dry powder spray gun for desulfurization and the catalytic cracking device provided by the utility model.

[0034] Example 1

[0035] The desulfurization dry powder spray gun provided in this embodiment is as follows: Figures 1 to 4 As shown, it includes a spray gun body 1; an alkaline dry powder inlet 2 is provided at one end of the spray gun body 1, and the other end of the spray gun body 1 is a curved surface structure; a plurality of flow hole assemblies are provided on the side wall of the spray gun body 1, and the plurality of flow hole assemblies are arranged at intervals along the axial direction of the spray gun body 1; each group of flow hole assemblies includes two flow holes, and the two flow holes are symmetrically arranged on the side wall of the spray gun body 1; the curved surface structure is provided with an end flow hole 8, and the two ends of the end flow hole 8 respectively extend to the side wall of the spray gun body 1, and the two ends of the end flow hole 8 are symmetrically arranged on the side wall of the spray gun body 1.

[0036] When in use, the spray gun body 1 is extended into the flue, and the spray gun body 1 is fixed to the side wall of the flue, and the axis of the spray gun body 1 is perpendicular to the flow direction of the flue gas to be purified.

[0037] Driven by high-pressure air, the alkaline dry powder enters the spray gun body 1 from the alkaline dry powder inlet 2. Inside the spray gun body 1, the alkaline dry powder is divided into multiple strands, which are ejected into the flue from multiple flow holes and the end flow hole 8 respectively. Since the multiple groups of flow hole assemblies are arranged at intervals along the axial direction of the spray gun body 1, and each group of flow hole assemblies includes two flow holes symmetrically arranged on the side wall of the spray gun body 1, the multiple flow holes are distributed more evenly in the cross section of the flue, which can make the alkaline dry powder more evenly distributed in the cross section of the flue, so that the alkaline dry powder can be more evenly dispersed in the flue, thereby increasing the contact area with the flue gas to be treated.

[0038] The alkaline dry powder flowing out of the end flow hole 8 is distributed in a fan shape, which can make the alkaline dry powder more comprehensively cover the entire flue cross section, fully contact with the flue gas, and increase the contact area between the alkaline dry powder and the flue gas.

[0039] Specifically, the outer contour of the spray gun body 1 is cylindrical, one end of the spray gun body 1 is an open structure, and the open structure serves as the alkaline dry powder inlet 2. The other end of the spray gun body 1 is a curved structure. In this embodiment, the other end of the spray gun body 1 is a spherical structure.

[0040] The side wall of the spray gun body 1 is provided with a plurality of flow hole assemblies, and the plurality of flow hole assemblies can be evenly spaced along the axial direction of the spray gun body 1 so that the plurality of flow hole assemblies are distributed more evenly.

[0041] Each group of flow hole assemblies includes two flow holes, and the two flow holes are symmetrically arranged on the side wall of the spray gun body 1, so that the two flow holes in each group of flow hole assemblies are symmetrically distributed on the side wall of the spray gun body 1. When the alkaline dry powder flows out to the flue through any group of flow hole assemblies, it can flow out through the two symmetrically distributed flow holes, so that the alkaline dry powder can be more evenly dispersed in the flue.

[0042] The end flow hole 8 has a U-shaped outer contour, with one end extending to one end of the side wall of the spray gun body 1, and the other end extending to the other end of the side wall of the spray gun body 1. The two ends of the end flow hole 8 are symmetrically arranged on the side wall of the spray gun body 1, and the end flow hole 8 is symmetrically arranged on the spherical structure, on the great circle of the spherical structure, and extends through the apex of the spherical structure. The alkaline dry powder flowing out of the end flow hole 8 is distributed in a fan-shaped manner, allowing the alkaline dry powder to more comprehensively cover the entire flue cross-section, fully contacting the flue gas, and increasing the contact area between the alkaline dry powder and the flue gas.

[0043] The number of the flow hole assemblies can be any suitable number such as 3, 4 or 5. The number of the flow hole assemblies can be set according to the diameter of the flue.

[0044] In this embodiment, the number of flow hole assemblies is 3 groups, and the 3 groups of flow hole assemblies are respectively a first flow hole assembly, a second flow hole assembly and a third flow hole assembly. Along the axis of the spray gun body 1, the first flow hole assembly, the second flow hole assembly and the third flow hole assembly are arranged in sequence, and the first flow hole assembly is arranged close to the alkaline dry powder inlet 2.

[0045] The first flow hole assembly includes two first flow holes 5, which are symmetrically arranged on the side wall of the spray gun body 1; the second flow hole assembly includes two second flow holes 6, which are symmetrically arranged on the side wall of the spray gun body 1; the third flow hole assembly includes two third flow holes 7, which are symmetrically arranged on the side wall of the spray gun body 1.

[0046] The length direction of the flow hole is as follows: Figure 1 In the direction indicated by the arrows ab, the width direction of the flow hole is as follows Figure 1 In the direction indicated by the arrow cd.

[0047] Furthermore, the widths of the plurality of flow holes are the same; along the axial direction of the spray gun body 1 and from the alkaline dry powder inlet 2 toward the curved surface structure, the lengths of the plurality of flow holes increase sequentially.

[0048] The width of the flow hole is the dimension of the flow hole in the width direction, and the length of the flow hole is the dimension of the flow hole in the length direction.

[0049] The plurality of flow holes on the spray gun body 1 have the same width.

[0050] In this embodiment, along the axial direction of the spray gun body 1 and in the direction from the alkaline dry powder inlet 2 toward the curved surface structure, the first flow hole 5, the second flow hole 6, and the third flow hole 7 are sequentially arranged. The lengths of the first flow hole 5, the second flow hole 6, and the third flow hole 7 increase in sequence. That is, the length of the first flow hole 5 is shorter than that of the second flow hole 6, and the length of the second flow hole 6 is shorter than that of the third flow hole 7. This achieves the effect of better coverage of the flue cross-section by the alkaline dry powder after spraying, thereby increasing the coverage area of ​​the flue cross-section by the alkaline dry powder.

[0051] Specifically, the lengths of the first flow hole 5, the second flow hole 6 and the third flow hole 7 at one end of the side wall of the spray gun body 1 increase successively, and the lengths of the first flow hole 5, the second flow hole 6 and the third flow hole 7 at the other end of the side wall of the spray gun body 1 increase successively.

[0052] Furthermore, along the axial direction of the spray gun body 1 , the length of the flow holes near the alkaline dry powder inlet 2 among the multiple flow holes is 20mm-30mm, the width of the flow holes near the alkaline dry powder inlet 2 among the multiple flow holes is 5mm-8mm, and the length of the multiple flow holes increases by 10mm sequentially.

[0053] In this embodiment, the length of the first circulation hole 5 is 20 mm-30 mm, the width of the first circulation hole 5 is 5 mm-8 mm, the length of the second circulation hole 6 is 10 mm longer than the length of the first circulation hole 5, the length of the third circulation hole 7 is 10 mm longer than the length of the second circulation hole 6, and the widths of the first circulation hole 5, the second circulation hole 6 and the third circulation hole 7 are the same.

[0054] The length of the first circulation hole 5 can be any suitable length such as 20 mm, 25 mm or 30 mm, and the width of the first circulation hole 5 can be any suitable length such as 5 mm, 6 mm, 7 mm or 8 mm.

[0055] Furthermore, the length of the end flow hole 8 is 100 mm to 150 mm, and the width of the end flow hole 8 is 20 mm to 30 mm.

[0056] Along the extending direction of the end flow hole 8 , the distance between the two ends of the end flow hole 8 is the length of the end flow hole 8 .

[0057] The width direction of the end flow hole 8 is as follows Figure 1 The width of the end flow hole 8 is the dimension in the width direction of the flow hole.

[0058] The length of the end circulation hole 8 can be any suitable length such as 100mm, 110mm, 120mm, 130mm, 140mm or 150mm. The length of the end circulation hole 8 can be adjusted according to the flue diameter and the alkaline dry powder delivery amount; the width of the end circulation hole 8 is any suitable width such as 20mm, 25mm or 30mm.

[0059] Furthermore, the dry powder spray gun for desulfurization also includes a guide plate 9; the guide plate 9 includes a first plate body 91 and a second plate body 92, the first plate body 91 and the second plate body 92 are vertically arranged, and the first plate body 91 and the second plate body 92 are fixedly connected; the first plate body 91 is connected to the inner side wall of the spray gun body 1, and the second plate body 92 is arranged opposite to the flow hole.

[0060] A guide plate 9 is provided on the inner side of each flow hole, that is, one guide plate 9 is provided corresponding to one flow hole.

[0061] The first plate 91 is fixedly connected to the inner wall of the spray gun body 1 . The first plate 91 is connected to the edge of the flow hole facing the curved structure. The second plate 92 is opposite to the flow hole and spaced apart.

[0062] When the alkaline dry powder flows out through the flow hole, it must pass through the guide plate 9. The guide plate 9 can change the movement direction of the alkaline dry powder into the flue. Under the action of the guide plate 9, the angle of the alkaline dry powder entering the flue is increased (the angle between the direction of the dry powder entering the flue and the axial direction of the spray gun body 1 is increased). The alkaline dry powder sprayed out of the two flow holes in each group of flow hole components is distributed in a "V" shape. Under the action of the guide plate 9, the angle of the "V" shape can be increased, so that the alkaline dry powder sprayed out of the two flow holes in each group of flow hole components is distributed in a "V" shape with a larger angle, so that the alkaline dry powder is more evenly dispersed. The first flow hole 5 is arranged close to the side wall of the flue, so that alkaline dry powder flows near the side wall of the flue.

[0063] The length of the second plate body 92 of the guide plate 9 is the same as the length of the flow hole opposite to it, and the width of the second plate body 92 of the guide plate 9 is the same as the width of the flow hole opposite to it.

[0064] Along the radial direction of the spray gun body 1 , the height of the first plate 91 is adjusted according to the diameter of the spray gun body 1 , and the distance between the two guide plates 9 corresponding to the two flow holes in each group of flow hole components is half the diameter of the spray gun body 1 .

[0065] Furthermore, the first plate body 91 and the second plate body 92 have a smooth transition.

[0066] The first plate body 91 and the second plate body 92 are connected by a smooth surface, so that the transition between the first plate body 91 and the second plate body 92 is smoother.

[0067] Furthermore, a fixing flange 4 is provided on the outer side wall of the spray gun body 1 .

[0068] The fixed flange 4 is used to connect with the flue opening flange. The size of the fixed flange 4 can be adjusted according to the diameter of the spray gun body 1 and the size of the flue opening flange.

[0069] The fixing flange 4 is fixed on the outer side wall of the spray gun body 1 , and the spray gun body 1 is fixed on the flue through the fixing flange 4 .

[0070] Furthermore, a connecting flange 3 is provided on the outer edge of the alkaline dry powder inlet 2 .

[0071] The connecting flange 3 is connected to the alkaline dry powder conveying system. The alkaline dry powder enters the spray gun body 1 from the alkaline dry powder inlet 2 under the drive of high-pressure air. The size of the connecting flange 3 can be adjusted according to the alkaline dry powder conveying amount and the diameter of the spray gun body 1.

[0072] Example 2

[0073] The catalytic cracking device provided in this embodiment includes a flue and the dry powder spray gun for desulfurization provided in Example 1; the spray gun body 1 extends into the flue, the spray gun body 1 is connected to the side wall of the flue, and the axial direction of the spray gun body 1 is perpendicular to the flue gas flow direction.

[0074] The spray gun body 1 is fixed to the side wall of the flue through a fixing flange 4, and the axial direction of the spray gun body 1 is perpendicular to the flow direction of the flue gas to be purified.

[0075] like Figure 3 and Figure 4 In the horizontal cross section of the flue shown, the flue gas to be purified flows in the vertical direction, the axial direction of the spray gun body 1 is arranged in the horizontal direction, one flow hole in each flow hole assembly is located on the front side of the side wall of the spray gun body 1, and the other flow hole in each flow hole assembly is located on the rear side of the side wall of the spray gun body 1. The end flow hole 8 extends to one end of the side wall of the spray gun body 1 and is located on the front side of the side wall of the spray gun body 1, and the other end of the end flow hole 8 extends to the side wall of the spray gun body 1 and is located on the rear side of the side wall of the spray gun body 1 in the figure. The front and rear directions are as shown in FIG. Figure 3 The direction indicated by the coordinate axis z.

[0076] The catalytic cracking unit provided in this embodiment employed the computational fluid dynamics software FLUENT, applying steady-state, non-isothermal, and incompressible conditions in a full-scale flue. The k-ε turbulence model was used to calculate the flow at the design load, assuming a uniform flue gas velocity distribution in the inlet. The simulations simulated the distribution of alkaline dry powder within a flue equipped with the desulfurization dry powder spray gun provided in this embodiment, with a flue diameter of 3400 mm.

[0077] The velocity distribution of the external flow field of the desulfurization dry powder spray gun was recorded at the horizontal section of the flue where the desulfurization dry powder spray gun is located. The velocity distribution can represent the area covered by the fluid. The study shows that the air flow velocity distribution at the horizontal section of the flue is uniform (such as Figure 3 As shown), and when the alkaline dry powder flows evenly into the desulfurization dry powder spray gun, after passing through each flow hole and the end flow hole 8 of the desulfurization dry powder spray gun, the alkaline dry powder fluid can basically cover the horizontal cross-section of the flue.

[0078] From the vector distribution (such as Figure 4 As shown, after the alkaline dry powder enters the spray gun body 1, the deflector plates 9 at the first three groups of flow holes act at a gentle exit angle, gradually diffusing toward the flue wall with uniform distribution and no eddy currents, thereby increasing the fluid coverage area. Furthermore, due to the larger end flow holes 8, the fluid sprayed from these end flow holes also covers a larger area, essentially covering the horizontal cross-section of the flue. This demonstrates that the desulfurization dry powder spray gun provided by this embodiment has excellent gas distribution performance.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dry powder spray gun for desulfurization, characterized in that: Including the spray gun body; One end of the spray gun body is provided with an alkaline dry powder inlet, and the other end of the spray gun body is a curved surface structure; The side wall of the spray gun body is provided with a plurality of flow hole assemblies, and the plurality of flow hole assemblies are spaced apart along the axial direction of the spray gun body; Each group of the flow hole assembly includes two flow holes, and the two flow holes are symmetrically arranged on the side wall of the spray gun body; The curved surface structure is provided with an end flow hole, both ends of the end flow hole respectively extend to the side wall of the spray gun body, and the two ends of the end flow hole are symmetrically arranged on the side wall of the spray gun body.

2. The dry powder spray gun for desulfurization according to claim 1, characterized in that: The number of the flow hole components is 3 to 5 groups.

3. The dry powder spray gun for desulfurization according to claim 1, characterized in that: The widths of the plurality of flow holes are the same; Along the axial direction of the spray gun body and in a direction from the alkaline dry powder inlet toward the curved surface structure, the lengths of the plurality of flow holes increase sequentially.

4. The dry powder spray gun for desulfurization according to claim 3, characterized in that: Along the axial direction of the spray gun body, the length of the flow holes close to the alkaline dry powder inlet among the multiple flow holes is 20mm-30mm, the width of the flow holes close to the alkaline dry powder inlet among the multiple flow holes is 5mm-8mm, and the length of the multiple flow holes increases by 10mm successively.

5. The dry powder spray gun for desulfurization according to claim 1, characterized in that: The length of the end flow hole is 100 mm to 150 mm, and the width of the end flow hole is 20 mm to 30 mm.

6. The dry powder spray gun for desulfurization according to claim 1, characterized in that: The desulfurization dry powder spray gun also includes a guide plate; The guide plate includes a first plate body and a second plate body, the first plate body and the second plate body are vertically arranged, and the first plate body and the second plate body are fixedly connected; The first plate is connected to the inner side wall of the spray gun body, and the second plate is arranged opposite to the flow hole.

7. The dry powder spray gun for desulfurization according to claim 6, characterized in that: The first plate body and the second plate body are smoothly transitioned.

8. The dry powder spray gun for desulfurization according to claim 1, characterized in that: The outer side wall of the spray gun body is provided with a fixing flange.

9. The dry powder spray gun for desulfurization according to claim 1, characterized in that: A connecting flange is provided on the outer edge of the alkaline dry powder inlet.

10. A catalytic cracking unit, characterized in that: It comprises a flue and a dry powder spray gun for desulfurization according to any one of claims 1 to 9; The spray gun body extends into the flue, the spray gun body is connected to the side wall of the flue, and the axial direction of the spray gun body is perpendicular to the flue gas flow direction.

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