Wall-attached air structure of front and back wall opposed firing boiler

Abstract

The present disclosure relates to a wall-attached air structure of a front and back wall opposed combustion boiler, which is used to solve the technical problem that the wall-attached air system on the furnace wall has limited mitigation effect on high-temperature corrosion of metal. The wall-attached air structure of the front and back wall opposed combustion boiler is installed on the front and back wall opposed combustion boiler, and the front and back wall opposed combustion boiler comprises a furnace wall and a plurality of burners. The furnace wall comprises a front wall and a back wall arranged oppositely, and two side walls arranged oppositely. The front wall, the back wall and the two side walls enclose a hearth. The plurality of burners are located in the hearth and arranged oppositely on the front wall and the back wall. The oppositely arranged burners can be opposed combustion to form a reducing atmosphere on the wall surface of the side wall. The reducing atmosphere comprises a low-concentration reducing atmosphere and a high-concentration reducing atmosphere. The wall-attached air structure of the front and back wall opposed combustion boiler comprises a plurality of wall-attached air nozzles arranged on the side wall. The number of wall-attached air nozzles in the low-concentration reducing atmosphere range is less than the number of wall-attached air nozzles in the high-concentration reducing atmosphere range.

Description

Technical Field

[0001] This disclosure relates to the field of boiler equipment technology, and more specifically, to a wall-mounted air structure for a front and rear wall opposed combustion boiler. Background Technology

[0002] Boilers generate heat radiation through combustion in the furnace via burners, which heats water into steam to power a steam turbine for electricity generation. The combustion of pulverized coal in the furnace easily produces a reducing atmosphere. This atmosphere contains large amounts of carbon monoxide (CO) and hydrogen sulfide (H₂S), which can easily cause high-temperature corrosion of metal components such as water-cooled wall tubes, superheaters, and reheaters when in contact with them. While existing technologies employ wall-mounted air systems to mitigate this corrosion, their effectiveness in mitigating high-temperature corrosion is limited, and large areas of metal corrosion still occur. Summary of the Invention

[0003] The purpose of this disclosure is to provide a wall-mounted air structure for a front and rear wall opposed combustion boiler, aiming to solve the technical problem that the wall-mounted air system on the furnace wall has limited effect on mitigating high-temperature corrosion of metals.

[0004] To achieve the above objectives, this disclosure provides a wall-mounted air structure for a front-and-rear wall opposed combustion boiler, which is installed on the front-and-rear wall opposed combustion boiler, the front-and-rear wall opposed combustion boiler comprising:

[0005] The furnace wall includes a front wall and a rear wall arranged opposite each other, and two side walls arranged opposite each other, the front wall, the rear wall, and the two side walls enclosing the furnace chamber; and,

[0006] Multiple burners are located inside the furnace and are arranged opposite to each other on the front wall and the rear wall. The oppositely arranged burners can burn in opposite directions to form a reducing atmosphere on the wall surface of the side wall. The reducing atmosphere includes a low-concentration reducing atmosphere and a high-concentration reducing atmosphere, wherein the concentration of the low-concentration reducing atmosphere is less than the concentration of the high-concentration reducing atmosphere.

[0007] The wall-mounted air structure of the front and rear wall opposed combustion boiler includes multiple wall-mounted air nozzles disposed on the side walls. The number of wall-mounted air nozzles in the low concentration reducing atmosphere range is less than the number of wall-mounted air nozzles in the high concentration reducing atmosphere range.

[0008] In some embodiments, the plurality of wall-mounted air nozzles are arranged in layers along the sidewall from low to high.

[0009] The number of wall-mounted air nozzles per layer in the low-concentration reducing atmosphere range is less than the number of wall-mounted air nozzles per layer in the high-concentration reducing atmosphere range.

[0010] In some embodiments, the plurality of wall-mounted air nozzles arranged in layers include: a first layer of wall-mounted air nozzles, a second layer of wall-mounted air nozzles, a third layer of wall-mounted air nozzles, and a fourth layer of wall-mounted air nozzles arranged sequentially along the side wall from low to high.

[0011] The first and second layer wall-mounted air nozzles are located within the low-concentration reducing atmosphere range, and each layer has two wall-mounted air nozzles; the third and fourth layer wall-mounted air nozzles are located within the high-concentration reducing atmosphere range, and each layer has four wall-mounted air nozzles.

[0012] In some embodiments, the front and rear wall opposed combustion boiler further includes a plurality of water-cooled wall tubes disposed inside the furnace and spirally mounted on the furnace wall;

[0013] The wall-mounted air nozzle passes through the space between adjacent water-cooled wall tubes, and the wall-mounted air nozzle is elongated and inclined along the spiral direction of the water-cooled wall tube.

[0014] In some embodiments, the wall-mounted air nozzle includes a first sub-nozzle and a second sub-nozzle;

[0015] Along the inclined direction of the water-cooled wall tube, the first sub-nozzle and the second sub-nozzle are staggered and arranged in a centrally symmetrical manner, and a plurality of the water-cooled wall tubes are inserted between the first sub-nozzle and the second sub-nozzle.

[0016] In some embodiments, the distance between the centers of adjacent wall-mounted air nozzles along the height direction of the sidewall is 4.5m-5.5m;

[0017] Along the horizontal direction, the distance between the centers of adjacent wall-mounted air nozzles is 2.5m-3.5m.

[0018] In some embodiments, the front wall and the rear wall are equipped with multiple layers of wall-mounted air nozzles along the height direction, and the wall-mounted air nozzles are located close to the side wall;

[0019] The spray direction of the wall-mounted air nozzle has a downward tilt angle, and the downward tilt angle of the wall-mounted air nozzle in the low concentration reducing atmosphere range is different from that in the high concentration reducing atmosphere range.

[0020] In some embodiments, the downward tilt angle of the wall-mounted air nozzle in the low-concentration reducing atmosphere range is smaller than that in the high-concentration reducing atmosphere range.

[0021] In some embodiments, a first layer of wall-mounted air nozzles, a second layer of wall-mounted air nozzles, and a third layer of wall-mounted air nozzles are sequentially arranged along the front wall and the rear wall from low to high.

[0022] The first layer of wall-mounted air nozzles is located within the low-concentration reducing atmosphere range, and the downward tilt angle of the first layer of wall-mounted air nozzles is 5°; the second layer of wall-mounted air nozzles and the third layer of wall-mounted air nozzles are located within the high-concentration reducing atmosphere range, and the downward tilt angle of the second layer of wall-mounted air nozzles and the third layer of wall-mounted air nozzles is 15°.

[0023] In some embodiments, the front and rear wall opposed combustion boiler further includes a hot primary air system and a hot secondary air system;

[0024] The wall-mounted air nozzle is drawn from the primary hot air system, and the wall-mounted air outlet is drawn from the secondary hot air system.

[0025] Compared with the prior art, the beneficial effects of this disclosure are:

[0026] This disclosure involves installing multiple wall-mounted air nozzles on the side walls of the furnace. These nozzles supply air into the furnace to supplement oxygen, ensuring complete combustion of pulverized coal and reducing the content of gases such as carbon monoxide (CO) and hydrogen sulfide (H2S), thus minimizing the reducing atmosphere. Furthermore, this disclosure uses fewer wall-mounted air nozzles in low-concentration reducing atmosphere areas and more in high-concentration reducing atmosphere areas, making the air supply within the furnace more targeted. This ensures complete combustion of pulverized coal in both high and low-concentration reducing atmosphere areas, thereby reducing the reducing atmosphere in both regions and mitigating the problem of large-area high-temperature corrosion of metal components such as water-cooled wall tubes within the furnace.

[0027] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0028] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0029] Figure 1This is a cross-sectional structural diagram of the boiler in the wall-mounted air structure of a front and rear wall opposed combustion boiler provided in an exemplary embodiment of the present disclosure.

[0030] Figure 2 yes Figure 1 A cross-sectional structural diagram of section AA of the opposed combustion boiler with front and rear walls in the middle;

[0031] Figure 3 yes Figure 1 Schematic diagram of the wall-mounted air nozzle structure arrangement of a wall-mounted air structure in a middle and front wall opposed combustion boiler;

[0032] Figure 4 This is a cross-sectional view of a spiral water-cooled wall tube installed in a front and rear wall opposed combustion boiler according to an exemplary embodiment of the present disclosure.

[0033] Figure 5 yes Figure 4 A schematic diagram of the wall-mounted air nozzles between adjacent water-cooled wall tubes;

[0034] Figure 6 yes Figure 1 A schematic diagram of the wall-mounted air nozzle structure on the front wall of a counter-flow combustion boiler with opposing front and rear walls.

[0035] Figure 7 yes Figure 6 A cross-sectional view of the wall-mounted air nozzles on the front wall with their downward tilt angle.

[0036] Explanation of reference numerals in the attached figures

[0037] 01-Front and rear wall opposed combustion boiler; 10-Furnace wall; 11-Front wall; 110-Wall-attached air nozzle; 111-First layer wall-attached air nozzle; 112-Second layer wall-attached air nozzle; 113-Third layer wall-attached air nozzle; 12-Rear wall; 13-Side wall; 130-Wall-attached air nozzle; 130a-First sub-nozzle; 130b-Second sub-nozzle; 131-First layer wall-attached air nozzle; 132-Second layer wall-attached air nozzle; 133-Third layer wall-attached air nozzle; 134-Fourth layer wall-attached air nozzle; 14-Furnace; 20-Burner; 30-Reducing atmosphere; 31-Low concentration reducing atmosphere; 32-High concentration reducing atmosphere; 40-Water-cooled wall tube; 51-Hot primary air system; 52-Hot secondary air system. Detailed Implementation

[0038] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0039] In the description of this disclosure, it should be understood that the terms "upper," "lower," etc., indicating orientation or positional relationship are defined based on the drawing orientation and are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientation construction and operation. Therefore, they should not be construed as limitations on this disclosure. In addition, the terms "inner" and "outer" refer to the inner and outer contours of the corresponding structures. Furthermore, the terms "first," "second," etc., are only used to distinguish one element from another and do not have sequential or importance implications.

[0040] In the description of this disclosure, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "connect," "link," and "install" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0041] This disclosure provides a wall-mounted air structure for a front and rear wall opposed combustion boiler, such as... Figure 1 and Figure 2 As shown, the wall-mounted air structure of the front and rear wall opposed combustion boiler can be installed on the front and rear wall opposed combustion boiler 01. The front and rear wall opposed combustion boiler 01 can include a furnace wall 10 and multiple burners 20. The furnace wall 10 can include a front wall 11 and a rear wall 12 arranged opposite each other, and two side walls 13 arranged opposite each other. The front wall 11, rear wall 12 and two side walls 13 can form a furnace 14. The multiple burners 20 can be located in the furnace 14 and arranged opposite each other on the front wall 11 and rear wall 12. The oppositely arranged burners 20 can perform opposed combustion to form a reducing atmosphere 30 on the wall surface of the side wall 13. The reducing atmosphere 30 can include a low-concentration reducing atmosphere 31 and a high-concentration reducing atmosphere 32. The concentration of the low-concentration reducing atmosphere 31 can be less than the concentration of the high-concentration reducing atmosphere 32. The wall-mounted air structure of the front and rear wall opposed combustion boiler may include multiple wall-mounted air nozzles 130 disposed on the side wall 13. The number of wall-mounted air nozzles 130 in the low concentration reducing atmosphere 31 range is less than the number of wall-mounted air nozzles 130 in the high concentration reducing atmosphere 32 range.

[0042] In this disclosure, the low-concentration reducing atmosphere 31 refers to the gas concentration relative to the high-concentration reducing atmosphere 32, and is not a limitation on the specific value of the reducing atmosphere 30 concentration. Depending on the different combustion conditions of the pulverized coal in the furnace 14, the number of wall-mounted air nozzles 130 within the ranges of low-concentration reducing atmosphere 31 and high-concentration reducing atmosphere 32 can be adjusted as needed. This disclosure does not impose any specific limitations on the specific concentration of the reducing atmosphere 30.

[0043] A front and rear wall opposed combustion boiler 01 refers to a boiler in which multiple burners 20 can be arranged opposite each other on the same axis of the front wall 11 and the rear wall 12, and the fuel (pulverized coal) and hot air can expand independently after being injected into the furnace 14. Figure 2 (As shown by the dashed line), and the combustion pattern of rising flames after impacting the center of the front wall 11 and the rear wall 12 ( Figure 1 (As indicated by the hollow arrow). In some embodiments, the burner 20 can also be configured to spray fuel (pulverized coal) and hot air in a rotating manner, so that the fuel and hot air sprayed from the front wall 11 and the rear wall 12 can be more fully mixed and combusted. The rotation directions of adjacent burners 20 can be opposite to increase the swirl intensity of the burner 20, thereby optimizing the combustion conditions within the furnace 14. Of course, multiple layers of burners 20 can also be provided on the front wall 11 and the rear wall 12. This disclosure does not impose any special limitation on the number of layers of burners 20 provided on the furnace wall 10.

[0044] Based on this, according to the different degrees of fuel combustion within the furnace 14, the combustion zone within the furnace 14 can be divided from bottom to top (as shown by the coordinates in the figure) into a main combustion zone, a reduction zone, and a burnout zone. The main combustion zone is located downstream of the flame, near and below the lowest burner 20, where the gas outside the flame is primarily oxidizing or weakly reducing. The reduction zone is located above the main combustion zone, above the lowest burner 20, where the gas outside the flame is primarily reducing atmosphere 30. Secondary hot air is introduced above the reduction zone to ensure complete fuel combustion; this area is the burnout zone. The reduction zone, under the combined effects of high temperature and reducing atmosphere 30, causes reducing corrosion to the metal. In actual combustion, the concentration of reducing atmosphere 30 at the top of the reduction zone is usually greater than that at the bottom, and the reducing atmosphere 30 mostly accumulates on the sidewalls 13 on both sides of the combustion flame, making the metal components on the sidewalls 13 susceptible to large-area corrosion.

[0045] This disclosure provides multiple wall-mounted air nozzles 130 on the sidewall 13 of the furnace wall 10. These nozzles supply hot air into the furnace 14, increasing oxygen levels and ensuring complete combustion of pulverized coal. This reduces the content of gases such as carbon monoxide (CO) and hydrogen sulfide (H2S), thus decreasing the reducing atmosphere 30. Furthermore, this disclosure uses fewer wall-mounted air nozzles 130 within the relatively low-concentration reducing atmosphere 31 and more within the relatively high-concentration reducing atmosphere 32, making the air supply to the furnace 14 more targeted. This ensures complete combustion of pulverized coal in both the high-concentration reducing atmosphere 32 and low-concentration reducing atmosphere 31, thereby reducing both the low-concentration and high-concentration reducing atmospheres 31 and 32, and improving the situation of large-scale corrosion of metal components within the furnace 14.

[0046] The range of reducing atmosphere 30 refers to the projection range of the reducing atmosphere 30 of the gas outside the flame onto the side wall 13 (the reducing atmosphere 30 accumulated on the side wall 13 is greater than that accumulated on the front wall 11 and the rear wall 12). The location and number of wall-mounted air nozzles 130 on the side wall 13 are specifically designed according to the concentration of reducing atmosphere 30. This not only reduces the content of reducing atmosphere 30 but also avoids problems such as complex preparation processes, difficult maintenance, damage to combustion energy in the furnace 14 and the overall structure of the furnace wall 10, and loss of make-up air energy caused by a large number of openings on the furnace wall 10. In other words, given the same number of openings on the furnace wall 10, this disclosure, by specifically setting different locations and numbers of wall-mounted air nozzles 130 based on the concentration of reducing atmosphere 30, achieves a more significant effect in reducing reducing atmosphere 30.

[0047] Specifically, such as Figure 3 As shown, multiple wall-mounted air nozzles 130 can be arranged in layers along the side wall 13 from low to high (from bottom to top in the figure). The number of wall-mounted air nozzles 130 per layer is less in the low-concentration reducing atmosphere 31 range than in the high-concentration reducing atmosphere 32 range. Since the concentration of the reducing atmosphere 30 at the top of the reduction zone is usually greater than that at the bottom, arranging the wall-mounted air nozzles 130 in layers on the side wall 13 allows multiple nozzles 130 to specifically cover the entire range of the reducing atmosphere 30, thereby improving the mixing degree between the makeup air sprayed from the nozzles 130 and the reducing atmosphere 30. Furthermore, the layered arrangement of the wall-mounted air nozzles 130 also helps maintain the regularity of the furnace wall 10 opening structure, avoiding messy openings on the furnace wall 10 and reducing the difficulty of opening the furnace wall 10.

[0048] Therefore, for a low-concentration reducing atmosphere 31, a smaller number of wall-mounted air nozzles 130 can be configured per layer. For a high-concentration reducing atmosphere 32, a larger number of wall-mounted air nozzles 130 can be configured per layer. Of course, the position of the wall-mounted air nozzles 130 can also be set according to the actual concentration of the reducing atmosphere 30 measured in the furnace 14. For example, depending on the different positions of the burners 20 in the furnace 14, the different ranges of the reducing atmosphere 30 formed, and the different concentrations of the reducing atmosphere 30 at different positions, the multiple wall-mounted air nozzles 130 can also be arranged in a circular or radial pattern on the side wall 13. This disclosure does not impose any special restrictions on the arrangement of the wall-mounted air nozzles 130 on the side wall 13.

[0049] In some implementations, such as Figure 3 As shown, the multiple wall-mounted air nozzles 130 arranged in layers may include: a first layer of wall-mounted air nozzles 131, a second layer of wall-mounted air nozzles 132, a third layer of wall-mounted air nozzles 133, and a fourth layer of wall-mounted air nozzles 134 arranged sequentially from low to high along the side wall 13. The first layer of wall-mounted air nozzles 131 and the second layer of wall-mounted air nozzles 132 can be located within a low-concentration reducing atmosphere 31, and each layer can have two wall-mounted air nozzles 130. The third layer of wall-mounted air nozzles 133 and the fourth layer of wall-mounted air nozzles 134 can be located within a high-concentration reducing atmosphere 32, and each layer can have four wall-mounted air nozzles 130.

[0050] This disclosure matches different concentrations of reducing atmosphere 30 by setting different numbers of wall-mounted air nozzles 130 in each layer. This allows for a smaller number of wall-mounted air nozzles 130 within the low-concentration reducing atmosphere 31 range and a larger number within the high-concentration reducing atmosphere 32 range. Therefore, multiple wall-mounted air nozzles 130 can not only cover the entire range of the reducing atmosphere 30 through layered arrangement, but also adapt to different concentrations of the reducing atmosphere 30 by setting different numbers in each layer, thereby significantly reducing the reducing atmosphere 30 within the furnace 14 and preventing large-scale corrosion of the metal. Of course, depending on the size of the reducing atmosphere 30 range, each layer of wall-mounted air nozzles 130 can also be set to five, six, or more. Furthermore, within the same concentration of reducing atmosphere 30, the number of wall-mounted air nozzles 130 in adjacent layers can be the same or different. This disclosure does not impose any specific restrictions on the exact number of wall-mounted air nozzles 130 in each layer.

[0051] Based on this, such as Figure 4As shown, the front and rear wall opposed combustion boiler 01 may also include multiple water-cooled wall tubes 40, which can be installed inside the furnace 14 and spirally mounted on the furnace wall 10. Wall-mounted air nozzles 130 can penetrate between adjacent water-cooled wall tubes 40, and the wall-mounted air nozzles 130 are elongated and inclined along the spiral direction of the water-cooled wall tubes 40. In this way, the spirally mounted water-cooled wall tubes 40 cause the water inside to rise in a rotating manner, thus receiving more heating time in the furnace 14 to heat the water inside the water-cooled wall tubes 40 into steam. At this time, the wall-mounted air nozzles 130 can be inclined along the spiral direction of the water-cooled wall tubes 40 to increase the air supply area of ​​the wall-mounted air nozzles 130, ensuring sufficient air for complete combustion of pulverized coal in the sidewall 13. Furthermore, when opening the wall-mounted air nozzles 130 between the water-cooled wall tubes 40, the water-cooled wall tubes 40 need to be bent along the outer periphery of the wall-mounted air nozzles 130. The elongated shape of the wall-mounted air nozzles 130 can also reduce the amount of work required for bending the water-cooled wall tubes 40, thereby reducing the difficulty of boiler manufacturing. During installation, rectangular air ducts can be welded to the wall-mounted air nozzles 130. Of course, the wall-mounted air nozzles 130 can also be set as circular openings; this disclosure does not impose any special restrictions on the opening shape of the wall-mounted air nozzles 130.

[0052] Specifically, such as Figure 5 As shown, the wall-mounted air nozzle 130 may include a first sub-nozzle 130a and a second sub-nozzle 130b. Along the inclined direction of the water-cooled wall tube 40, the first sub-nozzle 130a and the second sub-nozzle 130b may be staggered, and the first sub-nozzle 130a and the second sub-nozzle 130b may be centrally symmetrically arranged. Multiple water-cooled wall tubes 40 may be inserted between the first sub-nozzle 130a and the second sub-nozzle 130b. By configuring the wall-mounted air nozzle 130 with an staggered structure of the first sub-nozzle 130a and the second sub-nozzle 130b, the coverage area of ​​the wall-mounted air nozzle 130 can be increased along its elongated length. Multiple water-cooled wall tubes 40 can be inserted between the first sub-nozzle 130a and the second sub-nozzle 130b, so that the first sub-nozzle 130a and the second sub-nozzle 130b can be separated by a certain distance. On the one hand, it can increase the coverage area of ​​the wall-mounted air nozzle 130 in the width direction of the long strip. On the other hand, it can also avoid the problem of low strength and easy breakage of the water-cooled wall tube 40 caused by only a single water-cooled wall tube 40 inserted between the first sub-nozzle 130a and the second sub-nozzle 130b.

[0053] The structure of the above embodiments, such as Figure 3As shown, along the height direction of the side wall 13, the distance between the centers of adjacent wall-mounted air nozzles 130 can be set to 4.5m-5.5m. Along the horizontal direction, the distance between the centers of adjacent wall-mounted air nozzles 130 can be set to 2.5m-3.5m. The center of adjacent wall-mounted air nozzles 130 can be the center of centrosymmetry between the first sub-nozzle 130a and the second sub-nozzle 130b in the above embodiment. This results in a larger distance between adjacent wall-mounted air nozzles 130 vertically and horizontally on the side wall 13, thereby reducing the number of wall-mounted air nozzles 130 installed on the side wall 13 and lowering the difficulty of boiler manufacturing.

[0054] The above embodiments provide a detailed description of the location and number of wall-mounted air nozzles 130 on the side wall 13. To reduce the reducing atmosphere 30 within the furnace 14, such as... Figure 2 As shown, wall-mounted air nozzles 110 can also be installed on the front wall 11 and the rear wall 12. The following embodiment will use the front wall 11 as an example to describe the specific structure of the wall-mounted air nozzle 110 in detail. The wall-mounted air nozzle 110 installed on the rear wall 12 can be the same as the wall-mounted air nozzle 110 installed on the front wall 11. Figure 6 As shown, the front wall 11 and the rear wall 12 can be equipped with multiple layers of wall-mounted air nozzles 110 along the height direction (from bottom to top in the figure). The wall-mounted air nozzles 110 can be positioned close to the side wall 13. The spray direction of the wall-mounted air nozzles 110 has a downward tilt angle. The downward tilt angle of the wall-mounted air nozzles 110 within the low concentration reducing atmosphere 31 range can be different from the downward tilt angle of the wall-mounted air nozzles 110 within the high concentration reducing atmosphere 32 range.

[0055] The wall-mounted air nozzle 110 is positioned close to the side wall 13, allowing the supplementary hot air ejected from the nozzle to diffuse towards the center of the side wall 13. This enables the supplementary air from the nozzle 110 to mix with the supplementary air from the wall-mounted air nozzle 130, promoting complete combustion of pulverized coal and reducing the generation of gases such as carbon monoxide (CO) and hydrogen sulfide (H2S). Simultaneously, the downward tilt of the wall-mounted air nozzle 110 increases the upward resistance of the supplementary air ejected from the wall-mounted air nozzle 130 as it flows with the flue gas, reducing the diffusion of the airflow towards the outer wall and weakening the generation of the reducing atmosphere 30 at its source. Furthermore, the downward-spraying supplementary air extends along the depth of the furnace 14, thereby increasing the coverage area of ​​the supplementary air on the side wall 13.

[0056] For example, such as Figure 7As shown, the downward tilt angle of the wall-mounted air nozzle 110 within the low-concentration reducing atmosphere 31 range can be smaller than that within the high-concentration reducing atmosphere 32 range. In this way, since the high-concentration reducing atmosphere 32 is located higher than the low-concentration reducing atmosphere 31, the makeup air ejected by the wall-mounted air nozzle 110 with a larger downward tilt angle within the high-concentration reducing atmosphere 32 range can penetrate deeper into the furnace 14 than the makeup air ejected by the wall-mounted air nozzle 110 with a smaller downward tilt angle within the low-concentration reducing atmosphere 31 range. This increases the coverage of the wall-mounted airflow along the depth direction of the furnace 14 and reduces the reducing atmosphere 30 in the central region of the sidewall 13. Conversely, the low-concentration reducing atmosphere 31 has a lower concentration and is located lower, therefore the wall-mounted air nozzle 110 within the low-concentration reducing atmosphere 31 range can be set with a smaller downward tilt angle.

[0057] Specifically, such as Figure 7 As shown, a first layer of wall-mounted air nozzles 111, a second layer of wall-mounted air nozzles 112, and a third layer of wall-mounted air nozzles 113 are sequentially arranged along the front wall 11 and the rear wall 12 from low to high. The first layer of wall-mounted air nozzles 111 is located within the low-concentration reducing atmosphere 31, and the downward tilt angle of the first layer of wall-mounted air nozzles 111 is 5°. The second layer of wall-mounted air nozzles 112 and the third layer of wall-mounted air nozzles 113 are located within the high-concentration reducing atmosphere 32, and the downward tilt angle of the second layer of wall-mounted air nozzles 112 and the third layer of wall-mounted air nozzles 113 is 15°.

[0058] When the downward tilt angle of the first-layer wall-mounted air nozzle 111 is too small, the makeup air ejected by the first-layer wall-mounted air nozzle 111 may not be able to penetrate into the low-concentration reducing atmosphere 31 at the bottom of the reduction zone, resulting in insufficient reduction of the low-concentration reducing atmosphere 31. When the downward tilt angle of the first-layer wall-mounted air nozzle 111 is too large, the makeup air ejected by the first-layer wall-mounted air nozzle 111 may exceed the bottom of the reduction zone, resulting in a loss of makeup air. When the downward tilt angles of the second-layer wall-mounted air nozzle 112 and the third-layer wall-mounted air nozzle 113 are too small, the coverage area of ​​the wall-mounted airflow is small, and some areas still have reducing atmosphere 30. When the downward tilt angles of the second-layer wall-mounted air nozzle 112 and the third-layer wall-mounted air nozzle 113 are too large, the makeup air ejected by the second-layer wall-mounted air nozzle 112 and the third-layer wall-mounted air nozzle 113 may not completely cover the reducing atmosphere 30 area of ​​the side wall 13, resulting in the presence of reducing atmosphere 30 in the middle area of ​​the side wall 13.

[0059] Furthermore, depending on the scale of the opposed-wall combustion boiler 01, more layers of wall-mounted air nozzles 110 can be installed on the front wall 11 and rear wall 12. This disclosure does not impose any specific limitation on the number of layers of wall-mounted air nozzles 110 installed on the front wall 11 and rear wall 12. In some embodiments, the height of the wall-mounted air nozzles 110 installed on the front wall 11 and rear wall 12 can be higher than the height of the wall-mounted air nozzles 130 installed on the side wall 13. This not only allows the makeup air ejected by the wall-mounted air nozzles 110 to cover a large area of ​​the side wall 13, but also ensures that the makeup air ejected by the wall-mounted air nozzles 110 can be fully mixed with the makeup air ejected by the wall-mounted air nozzles 130.

[0060] In the above embodiments, such as Figure 1 As shown, the front and rear wall opposed combustion boiler 01 may also include a primary hot air system 51 and a secondary hot air system 52. The wall-mounted air nozzle 110 can be drawn from the primary hot air system 51, and the wall-mounted air nozzle 130 can be drawn from the secondary hot air system 52. In practical engineering, the primary hot air system 51 can be a system for providing the hot air required for combustion in the burner 20, and the secondary hot air system 52 can be a system for providing the hot air required for combustion in the burnout zone. Typically, the airflow of the primary hot air system 51 is greater than that of the secondary hot air system 52. Drawing the wall-mounted air nozzle 110 from the primary hot air system 51 and the wall-mounted air nozzle 130 from the secondary hot air system 52 can prevent the makeup air ejected from the wall-mounted air nozzle 130 from directly entering the flame and affecting the combustion energy within the furnace 14. Simultaneously, it allows the makeup air ejected from the wall-mounted air nozzle 110 to extend as far as possible to the middle of the side wall 13.

[0061] The airflow of the wall-mounted air nozzle 110 can be controlled by a pneumatic and manual adjustment device on the main pipeline leading from the hot primary air system 51, or the airflow of each individual wall-mounted air nozzle 110 can be individually adjusted by a manual adjustment baffle on each nozzle. Similarly, the airflow of the wall-mounted air outlet 130 can be controlled by a pneumatic and manual adjustment device on the main pipeline leading from the hot secondary air system 52, or the airflow of each individual outlet can be individually adjusted by a manual adjustment baffle on each outlet.

[0062] In summary, the wall-mounted air structure of the front and rear wall-opposed combustion boiler provided in this disclosure, through the specific design of the position and number of wall-mounted air nozzles 110 and 130, allows for timely air replenishment at the middle position of the side wall 13. This prevents the accumulation of reducing atmosphere 30 on the middle wall surface of the side wall 13, thus avoiding large-area corrosion of metal components such as the water-cooled wall tubes 40. The modified front and rear wall-opposed combustion boiler 01 operates stably and does not negatively affect boiler output or key operating parameters. Furthermore, the hydrodynamic characteristics of the front and rear wall-opposed combustion boiler 01 are not disrupted, greatly avoiding the problems of tube wall overheating and tube rupture caused by metal corrosion of metal components such as the water-cooled wall tubes 40.

[0063] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0064] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0065] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A wall-mounted air structure for a front and rear wall-opposed combustion boiler, characterized in that, Installed on a front and rear wall opposed combustion boiler, the front and rear wall opposed combustion boiler includes: The furnace wall includes a front wall and a rear wall arranged opposite each other, and two side walls arranged opposite each other, the front wall, the rear wall, and the two side walls enclosing the furnace chamber; and, Multiple burners are located inside the furnace and are arranged opposite to each other on the front wall and the rear wall. The oppositely arranged burners can burn in opposite directions to form a reducing atmosphere on the wall surface of the side wall. The reducing atmosphere includes a low-concentration reducing atmosphere and a high-concentration reducing atmosphere, wherein the concentration of the low-concentration reducing atmosphere is less than the concentration of the high-concentration reducing atmosphere. The wall-mounted air structure of the front and rear wall-opposed combustion boiler includes multiple wall-mounted air nozzles disposed on the side walls. The number of wall-mounted air nozzles in the low-concentration reducing atmosphere range is less than the number of wall-mounted air nozzles in the high-concentration reducing atmosphere range.

2. The wall-mounted air structure of the front and rear wall-opposed combustion boiler according to claim 1, characterized in that, The plurality of wall-mounted air nozzles are arranged in layers along the side wall from low to high. The number of wall-mounted air nozzles per layer in the low-concentration reducing atmosphere range is less than the number of wall-mounted air nozzles per layer in the high-concentration reducing atmosphere range.

3. The wall-mounted air structure of the front and rear wall-opposed combustion boiler according to claim 2, characterized in that, The multiple wall-mounted air nozzles arranged in layers include: a first layer of wall-mounted air nozzles, a second layer of wall-mounted air nozzles, a third layer of wall-mounted air nozzles, and a fourth layer of wall-mounted air nozzles arranged sequentially along the side wall from low to high. The first and second layer wall-mounted air nozzles are located within the low-concentration reducing atmosphere range, and each layer has two wall-mounted air nozzles; the third and fourth layer wall-mounted air nozzles are located within the high-concentration reducing atmosphere range, and each layer has four wall-mounted air nozzles.

4. The wall-mounted air structure of the front and rear wall-opposed combustion boiler according to claim 1, characterized in that, The front and rear wall opposed combustion boiler also includes multiple water-cooled wall tubes, which are disposed inside the furnace and spirally mounted on the furnace wall. The wall-mounted air nozzle passes through the space between adjacent water-cooled wall tubes, and the wall-mounted air nozzle is elongated and inclined along the spiral direction of the water-cooled wall tube.

5. The wall-mounted air structure of the front and rear wall-opposed combustion boiler according to claim 4, characterized in that, The wall-mounted air nozzle includes a first sub-nozzle and a second sub-nozzle; Along the inclined direction of the water-cooled wall tube, the first sub-nozzle and the second sub-nozzle are staggered and arranged in a centrally symmetrical manner, and a plurality of the water-cooled wall tubes are inserted between the first sub-nozzle and the second sub-nozzle.

6. The wall-mounted air structure of the front and rear wall-opposed combustion boiler according to claim 5, characterized in that, Along the height direction of the sidewall, the distance between the centers of adjacent wall-mounted air nozzles is 4.5m-5.5m; Along the horizontal direction, the distance between the centers of adjacent wall-mounted air nozzles is 2.5m-3.5m.

7. The wall-mounted air structure of the front and rear wall-opposed combustion boiler according to any one of claims 1-6, characterized in that, The front wall and the rear wall are equipped with multiple layers of wall-mounted air nozzles along the height direction, and the wall-mounted air nozzles are located close to the side wall; The spray direction of the wall-mounted air nozzle has a downward tilt angle, and the downward tilt angle of the wall-mounted air nozzle in the low concentration reducing atmosphere range is different from that in the high concentration reducing atmosphere range.

8. The wall-mounted air structure of the front and rear wall-opposed combustion boiler according to claim 7, characterized in that, The downward tilt angle of the wall-mounted air nozzle in the low-concentration reducing atmosphere range is smaller than that in the high-concentration reducing atmosphere range.

9. The wall-mounted air structure of the front and rear wall-opposed combustion boiler according to claim 8, characterized in that, A first layer of wall-mounted air nozzles, a second layer of wall-mounted air nozzles, and a third layer of wall-mounted air nozzles are sequentially arranged along the front wall and the rear wall from low to high. The first layer of wall-mounted air nozzles is located within the low-concentration reducing atmosphere range, and the downward tilt angle of the first layer of wall-mounted air nozzles is 5°; the second layer of wall-mounted air nozzles and the third layer of wall-mounted air nozzles are located within the high-concentration reducing atmosphere range, and the downward tilt angle of the second layer of wall-mounted air nozzles and the third layer of wall-mounted air nozzles is 15°.

10. The wall-mounted air structure of the front and rear wall-opposed combustion boiler according to claim 7, characterized in that, The front and rear wall opposed combustion boiler also includes a hot primary air system and a hot secondary air system; The wall-mounted air nozzle is drawn from the primary hot air system, and the wall-mounted air outlet is drawn from the secondary hot air system.

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