Boiler flue gas treatment equipment and boiler unit system

Abstract

The present application discloses a boiler flue gas treatment device and a boiler unit system, belonging to the technical field of flue gas treatment. The disclosed boiler flue gas treatment device includes a furnace body, a main burner mechanism, a reduction mechanism, and an overfire air mechanism. The furnace body has a furnace chamber, and the main burner mechanism, the reduction mechanism, and the overfire air mechanism are arranged in sequence from bottom to top in the height direction of the furnace chamber; the furnace body is provided with a secondary air nozzle, and the secondary air nozzle is oppositely arranged with respect to the combustion area of the main burner mechanism; the overfire air mechanism includes a first overfire air nozzle and a second overfire air nozzle, and at least part of the first overfire air nozzle is provided with an avoidance space, and the second overfire air nozzle is arranged in the avoidance space. The above solution can solve the problem that there is insufficient layout space in the height direction of the current boiler flue gas treatment device in the furnace chamber.

Description

Technical Field

[0001] This application belongs to the technical field of boiler flue gas treatment, and specifically relates to a boiler flue gas treatment device and a boiler unit system. Background Art

[0002] In pulverized coal boilers of power plants, in order to suppress the generation of NO X in the furnace, air staging is usually carried out along the height direction in the furnace. The staged air mainly consists of separated overfire air arranged at a certain height above the main combustion zone, and thus an overfire zone is formed.

[0003] Currently, in order to ensure that the overfire zone has a better burnout effect, the overfire zone includes a relatively large number of overfire air nozzles. This will cause a reduction in the proportion of the main combustion zone and the reduction zone in the furnace height direction, which will not only lead to an increase in unburned components such as carbon particles and CO in the flue gas, but also weaken the treatment effect on NO X ; however, if the number of overfire air nozzles is reduced, the oxygen supply in the overfire zone will be insufficient, resulting in a poor burnout effect. Summary of the Invention

[0004] The purpose of the embodiments of this application is to provide a boiler flue gas treatment device and a boiler unit system, which can solve the problem of insufficient layout space in the height direction of the furnace of the current boiler flue gas treatment device.

[0005] To solve the above technical problems, this application is implemented as follows:

[0006] On the one hand, the embodiments of this application provide a boiler flue gas treatment device, which includes a furnace body, a main burner mechanism, a reduction mechanism, and an overfire air mechanism. The furnace body has a furnace chamber, and the main burner mechanism, the reduction mechanism, and the overfire air mechanism are arranged in sequence from bottom to top in the height direction of the furnace chamber; the main burner mechanism includes secondary air nozzles, and the secondary air nozzles are arranged opposite to the combustion area of the main burner mechanism;

[0007] The overfire air mechanism includes a first overfire air nozzle and a second overfire air nozzle, and an avoidance space is arranged in at least part of the first overfire air nozzle, and the second overfire air nozzle is arranged in the avoidance space.

[0008] On the other hand, the embodiments of this application provide a boiler unit system, which includes the aforementioned boiler flue gas treatment device.

[0009] In the boiler flue gas treatment equipment disclosed in the embodiments of the present application, the overfire air mechanism includes a first overfire air nozzle and a second overfire air nozzle. At least part of the first overfire air nozzle is provided with an avoidance space, and the second overfire air nozzle is arranged in the avoidance space. With such an arrangement, the compactness of the first overfire air nozzle and the second overfire air nozzle is relatively high, which can improve the overall integration degree of the overfire air mechanism. Compared with the prior art in which the overfire air nozzles are arranged at intervals, undoubtedly, more overfire air nozzles can be arranged per unit area, and thus the purpose of balanced layout in the main combustion zone, reduction zone and burnout zone can be achieved.

[0010] Meanwhile, in the boiler flue gas treatment equipment disclosed in the embodiments of the present application, the second overfire air nozzle is equivalent to being embedded in the first overfire air nozzle. The overfire air ejected from the two overfire air nozzles can converge into a stronger synthetic air, which can cover and spread to a larger area when sprayed into the burnout zone, optimize the flow field in the burnout zone, and the oxygen content of the synthetic air is more sufficient. Furthermore, the unburned components in the flue gas can be fully burned, so as to improve the cleanliness of the flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic structural diagram of the boiler flue gas treatment equipment disclosed in the embodiments of the present application;

[0012] Figure 2 is a partial side view structural diagram of the furnace disclosed in the embodiments of the present application;

[0013] Figure 3 is about Figure 2 a partial enlarged view of A in

[0014] Figure 4 is a schematic structural diagram of a spray element disclosed in the embodiments of the present application;

[0015] DESCRIPTION OF THE REFERENCE NUMERALS

[0016] 100 - furnace body, 110 - furnace

[0017] 200 - main burner mechanism, 210 - secondary air nozzle, 220 - ignition element

[0018] 300 - reduction mechanism, 310 - spray element, 320 - reductant supply source, 330 - main conveying pipeline, 340 - pumping assembly, 350 - circulating bypass pipeline, 360 - distribution assembly

[0019] 400 - overfire air mechanism, 410 - first overfire air nozzle, 411 - avoidance space, 420 - second overfire air nozzle

[0020] 500 - first air supply mechanism, 600 - second air supply mechanism. DETAILED DESCRIPTION

[0021] Next, in combination with the accompanying drawings in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0022] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are usually of the same category, and the number of objects is not limited. For example, the first object can be one or multiple. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / ", generally represents an "or" relationship between the associated objects before and after.

[0023] The following will, in combination with the accompanying drawings, detail the technical solutions disclosed in the embodiments of the present application.

[0024] Please refer to Figures 1 to 4 , an embodiment of the present application discloses a boiler flue gas treatment device, which can treat the flue gas generated by a power plant boiler. The disclosed boiler flue gas treatment device includes a furnace body 100, a main burner mechanism 200, a reduction mechanism 300, and an overfire air mechanism 400.

[0025] Among them, the furnace body 100 is the main structure of the boiler flue gas treatment device. It can not only provide an installation and support foundation for other structures, but also play a certain protective role, and at the same time provide a treatment space for the flue gas treatment process. In this embodiment, the furnace body 100 has a furnace chamber 110, and the furnace chamber 110 is the treatment space for the boiler flue gas.

[0026] The main burner mechanism 200, the reduction mechanism 300, and the overfire air mechanism 400 are all functional structures of the boiler flue gas treatment device. The main burner mechanism 200 can realize the combustion of the air-powder mixture, and the air-powder mixture will generate flue gas during the combustion process. Within the action range of the main burner mechanism 200, a main combustion zone is formed in the furnace chamber 110.

[0027] The reduction mechanism 300 can perform reduction treatment on NO in the flue gas. X Specifically, NO in the flue gas generated by the power plant boiler XIt mainly includes polluting NO and NO2. After being reduced, NO and NO2 generate non-polluting N2 to improve the cleanliness of the flue gas. Within the action range of the reduction mechanism 300, a reduction zone is formed in the furnace 110.

[0028] To avoid the secondary generation of NO X , the action area of the reduction mechanism 300 can be set within the temperature window range of 1200 - 1400 °C, where the average molar concentration of oxygen in this temperature window is less than 1%. Therefore, it can further ensure that the reducing agent medium is difficult to be directly oxidized to NO under oxygen-deficient conditions X , but is oxidized to non-polluting N2. At the same time, it can also ensure the reduction effect on NO X .

[0029] The burnout air mechanism 400 can provide burnout air, which can provide oxygen for the unburned components in the flue gas (such as carbon particles, CO, etc.) and promote their full combustion, thereby reducing the proportion of unburned components in the flue gas to improve the cleanliness of the flue gas. Within the action range of the burnout air mechanism 400, a burnout zone is formed in the furnace 110.

[0030] In this embodiment, the main burner mechanism 200, the reduction mechanism 300, and the burnout air mechanism 400 are arranged in sequence from bottom to top in the height direction of the furnace 110. Based on the above settings, the air staging technology is applied in the flue gas treatment equipment of this boiler. With such settings, when the pulverized coal-air mixture burns in the main combustion zone, flue gas will be generated, and the flue gas will gradually rise through the reduction zone and the burnout zone in sequence.

[0031] Specifically, the main burner mechanism 200 includes a secondary air nozzle 210, and the secondary air nozzle 210 is arranged opposite to the combustion area of the main burner mechanism 200. It should be understood that the main burner mechanism 200 includes a primary air nozzle. Before combustion, the pulverized coal forms a pulverized coal-air mixture with the primary air. The pulverized coal-air mixture is transported from the primary air nozzle to the furnace 110 via the pulverized coal delivery air duct and burns in the combustion area of the main burner mechanism 200. The primary air serves to transport the pulverized coal, and the secondary air in the main combustion zone ejected from the secondary air nozzle 210 serves to provide a preset amount of combustion-supporting oxygen.

[0032] It should be noted that based on the air staging technology, during the combustion process in the main combustion zone, since the secondary air ejected from the secondary air nozzle 210 supplies less oxygen than the required amount, the nitrogen element cannot obtain enough oxygen element, thus effectively suppressing the generation of NO X ; of course, because the supplied oxygen is insufficient, unburned components are left in the flue gas. Of course, to ensure that the pulverized coal-air mixture can burn in the main combustion zone, the main burner mechanism 200 also includes an ignition element 220, and the ignition element 220 is usually preferably an ignition gun.

[0033] In this embodiment, the overfire air mechanism 400 includes a first overfire air nozzle 410 and a second overfire air nozzle 420. An avoidance space 411 is provided in the first overfire air nozzle 410, and the second overfire air nozzle 420 is arranged in the avoidance space 411. It should be understood that with such an arrangement, the second overfire air nozzle 420 is integrally arranged in the first overfire air nozzle 410. Compared with the prior art where the two overfire air nozzles are arranged at intervals, it undoubtedly has better compactness and improves the overall integration degree of the overfire air mechanism 400.

[0034] It should be noted that the overfire air nozzle is usually part of the overfire air duct. Thus, the above implementation manner can also be understood as that the first overfire air nozzle 410 is part of the first overfire air duct, an avoidance space 411 is provided in the first overfire air duct, and the second overfire air nozzle 420 is part of the second overfire air duct, and the second overfire air duct is arranged in the avoidance space 411, so that the second overfire air nozzle 420 is embedded in the first overfire air nozzle 410, enabling the two overfire airflows to converge and combine into a combined airflow.

[0035] Under normal circumstances, as Figure 3 shown, the second overfire air nozzle 420 is arranged corresponding to the center of the first overfire air nozzle 410, which is more convenient for the two overfire airflows to converge. Of course, the second overfire air nozzle 420 can also be arranged to tend to one side of the first overfire air nozzle 410, and this embodiment does not limit it.

[0036] Meanwhile, this embodiment does not limit the specific shape of the second overfire air nozzle 420. As Figure 3 shown, the second overfire air nozzle 420 can be set as a rectangular nozzle, and of course, it can also be set as a circular nozzle, a triangular nozzle, etc.

[0037] From the above description, it can be seen that in the boiler flue gas treatment equipment disclosed in the embodiment of the present application, the overfire air mechanism 400 includes a first overfire air nozzle 410 and a second overfire air nozzle 420. An avoidance space 411 is provided in at least part of the first overfire air nozzle 410, and the second overfire air nozzle 420 is arranged in the avoidance space 411. With such an arrangement, the first overfire air nozzle 410 and the second overfire air nozzle 420 have higher compactness, can improve the overall integration degree of the overfire air mechanism 400, and compared with the prior art where the overfire air nozzles are arranged at intervals, it can undoubtedly arrange more overfire air nozzles per unit area, and thus can achieve the purpose of evenly arranging the main combustion zone, the reduction zone, and the burnout zone.

[0038] At the same time, in the boiler flue gas treatment equipment disclosed in the embodiment of the present application, the second burnout air nozzle 420 is equivalent to being embedded in the first burnout air nozzle 410, and the burnout winds ejected from the two burnout air nozzles can converge into a stronger synthetic wind, which can cover and diffuse to a larger area when sprayed into the burnout zone, thereby optimizing the flow field in the burnout zone, and the synthetic wind has more oxygen content, thereby enabling the incompletely burned components in the flue gas to be fully burned, thereby improving the cleanliness of the flue gas.

[0039] In this embodiment, the specific structure of the burnout air mechanism 400 is various, which can be determined according to the specific layout of the three regions of the main combustion zone, the reduction zone and the burnout zone. Generally, the burnout air mechanism 400 can include multiple first burnout air nozzles 410, so as to provide sufficient burnout air.

[0040] At least part of the plurality of first overburnt air nozzles 410 is provided with an avoidance space 411, and the second overburnt air nozzles 420 are provided in the avoidance space 411. It should be understood that in this embodiment, the second overburnt air nozzles 420 may be embedded in part of the first overburnt air nozzles 410, or the second overburnt air nozzles 420 may be embedded in all the first overburnt air nozzles 410. In the former embodiment, the integration degree of the overburnt air mechanism 400 is changed based on the number of the second overburnt air nozzles 420, and in the latter embodiment, the integration degree of the overburnt air mechanism 400 is maximized.

[0041] Furthermore, the plurality of first overcombustion air jets 410 may be arranged in a plurality of groups along the circumferential direction in the furnace 110 , and each group of first overcombustion air jets 410 is arranged in the height direction of the furnace 110 . It should be understood that, under such an arrangement, the burnout air ejected from different burnout air nozzles in each group of first burnout air nozzles 410 can form a burnout air area, which can undoubtedly achieve better burnout effect and flow field optimization effect compared with the arrangement of a single burnout air nozzle; secondly, since the multiple first burnout air nozzles 410 are divided into multiple groups and arranged circumferentially in the furnace 110, that is, multiple burnout air areas are formed in the circumferential direction of the furnace 110, all the rising flue gas can be covered by the burnout air as much as possible, so that the incompletely burned components therein can be burned; furthermore, since each group of first burnout air nozzles 410 is arranged in the height direction of the furnace 110, the burnout air mechanism 400 achieves burnout air coverage within a certain range in the height direction of the furnace 110, and during the rising process of the flue gas, the flue gas can have a longer time in contact with the burnout air, thereby improving the burnout efficiency of the burnout air mechanism 400.

[0042] Meanwhile, at least part of each set of overfire air nozzles 410 is provided with an avoidance space 411, and a second overfire air nozzle 420 is arranged in the avoidance space 411. That is to say, in each set of overfire air nozzles 410, part of them can be embedded with the second overfire air nozzles 420, or all of them can be embedded with the second overfire air nozzles 420. Combining the foregoing, with such a setting, undoubtedly, the burnout efficiency of the overfire air mechanism 400 and the flow field optimization effect can be further optimized, and the structural space utilization rate of the boiler flue gas treatment equipment can also be improved.

[0043] Under normal circumstances, the overfire air mechanism 400 is dispersedly arranged at the four corners of the furnace body 100. As Figure 2 shown, in a specific embodiment, a set of first overfire air nozzles 410 are respectively arranged at the corners of the furnace body 100. A set of first overfire air nozzles 410 includes four first overfire air nozzles 410 arranged along the height direction of the furnace chamber 110, and a second overfire air nozzle 420 is embedded in one of the overfire air nozzles 410.

[0044] Of course, the specific installation position of the overfire air mechanism 400 is not limited in this embodiment, and the overfire air mechanism 400 can also be arranged on the inner furnace wall of the furnace body 100.

[0045] Since air vortices will be formed during the upward movement of the flue gas, it may be difficult for the overfire air to pass through the air vortices and enter the central area of the air vortices. As a result, it will be difficult for the flue gas inside the air vortex center to come into contact with the overfire air, resulting in more unburned components in this part of the flue gas, and ultimately the flue gas will still have a high level of pollution. Based on this, in an optional solution, the overfire air velocity of the second overfire air nozzle 420 can be greater than that of the first overfire air nozzle 410.

[0046] Specifically, there is a velocity difference between the overfire air of the second overfire air nozzle 420 and the overfire air of the first overfire air nozzle 410. Relatively speaking, the synthetic air includes a high-speed air in the middle and a low-speed air on the periphery. The high-speed air can form a high-speed jet with strong rigidity, which can cause the synthetic air to form an entrainment effect on the surrounding flue gas, making more oxygen in the surrounding area be entrained into the synthetic air, thereby eliminating unburned components such as carbon particles and CO in the flue gas. Undoubtedly, this can expand the burnout area of the overfire air mechanism 400; at the same time, due to the existence of the high-speed air in the synthetic air, the airflow formed by the synthetic air is stronger, which can pass through the air vortex and enter the central area of the air vortex (usually located in the central area of the furnace chamber 110), and come into contact with the unburned components in the central area of the air vortex to achieve complete combustion, thereby reducing the proportion of components such as carbon particles and CO in the flue gas to improve the cleanliness of the flue gas. Undoubtedly, this further expands the burnout area of the overfire air mechanism 400.

[0047] In this embodiment, the specific wind speed of the burnout air in the second burnout air nozzle 420 is not limited. The wind speed of the second burnout air nozzle 420 is usually selectable as 80 m / s - 100 m / s. For example, it can be specifically selected as 85 m / s or 90 m / s. Of course, the wind speed of the burnout air in the second burnout air nozzle 420 can be determined according to the actual wind speed of the burnout air in the first burnout air nozzle 410 to ensure that a speed difference can be formed between the two. It should be noted that the wind speeds of both the first burnout air nozzle 410 and the second burnout air nozzle 420 are related to the capacity of the furnace 110 of the equipment, so they can be determined according to the actual working conditions. In some embodiments, the wind speed of the burnout air in the second burnout air nozzle 420 can be greater than 100 m / s.

[0048] Furthermore, in order to facilitate the synthetic air to pass through the gas cyclone and enter the central area of the gas cyclone, the second burnout air nozzle 420 can be arranged opposite to the central area of the furnace 110. It should be understood that since the flue gas rises along the height direction of the furnace 110, the central area of the flue gas cyclone generally coincides with the central area of the furnace 110. With such an arrangement, the air flow movement path of the synthetic air is directed towards the central area of the gas cyclone. Undoubtedly, it can prevent the synthetic air from deviating from the gas cyclone during movement, enabling the synthetic air to smoothly pass through the gas cyclone and enter the central area of the gas cyclone, and contact with the unburned components in the central area of the gas cyclone to achieve complete combustion, thereby reducing the proportion of components such as carbon particles and CO in the flue gas and improving the cleanliness of the flue gas.

[0049] Normally, the first burnout air nozzle 410 and the second burnout air nozzle 420 are of a fixed configuration. Of course, they can also be of a swinging configuration, that is, the first burnout air nozzle 410 and the second burnout air nozzle 420 can swing in their circumferential or radial directions. For example, the first burnout air nozzle 410 and the second burnout air nozzle 420 can perform swinging actions up and down, left and right.

[0050] In this embodiment, there are various types of reduction mechanisms 300. For example, the reduction mechanism 300 can include a filter screen, and a reducing agent medium can be arranged on the filter screen. When the flue gas contacts the filter screen during its upward movement, the flue gas will contact the reducing agent medium to thereby achieve the reduction of NO X As shown in Figure 4 In another specific embodiment, the reduction mechanism 300 can include a plurality of spraying elements 310. The plurality of spraying elements 310 are arranged on the inner furnace wall of the furnace body 100 and are arranged circumferentially.

[0051] It should be understood that the spraying elements 310 can spray the reducing agent medium in a mist or fluid state. The flue gas contacts the reducing agent medium during its upward movement, and the reducing agent medium can reduce NO XDenitrification treatment is carried out by reduction, and pollution-free X2 is generated. At the same time, since multiple spraying elements 310 are circumferentially arranged on the inner furnace wall of the furnace body 100, it is undoubtedly possible to make the reducing agent medium evenly distributed in the furnace chamber 110 after being ejected, so that the reducing agent medium can cover a larger range of flue gas.

[0052] In order to further improve the coverage range of the spraying element 310, as Figure 2 shown, in an alternative solution, multiple spraying elements 310 can be arranged in multiple layers in the height direction of the furnace chamber 110, and two adjacent spraying elements 310 belonging to different layers are staggeredly distributed.

[0053] Specifically, the spraying elements 310 arranged in multiple layers undoubtedly result in a larger number of spraying elements 310 being provided in the furnace chamber 110, so that the amount of the reducing agent medium ejected by the spraying elements 310 can be increased, and thus it can be ensured that the flue gas can be fully denitrified when contacting the reducing agent medium; the staggered distribution of two adjacent spraying elements 310 belonging to different layers means that the two spraying elements 310 in adjacent layers are not in the same height direction, and there are also spraying elements 310 corresponding to the area between two adjacent spraying elements 310 in the same layer in another layer. With such an arrangement, it is undoubtedly possible to make the spraying elements 310 in the furnace chamber 110 more densely arranged, thereby avoiding the formation of omission areas between adjacent spraying elements 310.

[0054] In this embodiment, there are various types of reducing agent media. Usually, the reducing agent medium can be selected as urea solution, ammonia-containing solution, etc. This embodiment does not limit the spraying angle range of the spraying element 310 either. For example, the spraying angle range of the spraying element 310 can be selected as 30°, 60°, 90°, etc.

[0055] Usually, the reduction mechanism 300 further includes a reducing agent supply source 320, a main conveying pipeline 330, and a pumping assembly 340. The reducing agent supply source 320 is connected to multiple spraying elements 310 through the main conveying pipeline 330, and the pumping assembly 340 is arranged on the main conveying pipeline 330. Specifically, based on the pumping assembly 340, the reducing agent medium in the reducing agent supply source 320 can be smoothly conveyed to the spraying elements 310 and then ejected by the spraying elements 310 in the furnace chamber 110. The pumping assembly 340 can usually be selected as a water pump.

[0056] In this embodiment, the specific type of the reducing agent supply source 320 is not limited. It can usually be a reducing agent preparation device. Of course, it can also directly select the urea solution tank in the urea hydrolysis workshop of the power plant.

[0057] The reduction mechanism 300 may further include a circulating bypass pipeline 350. One end of the circulating bypass pipeline 350 is connected to the main conveying pipeline 330, and the other end of the circulating bypass pipeline 350 is connected to the reducing agent supply source 320. It should be noted that the reducing agent medium in the main conveying pipeline 330 can return to the reducing agent supply source 320 through the circulating bypass pipeline 350, so that the flow rate in the main conveying pipeline 330 under different working conditions can be flexibly adjusted to match the flue gas volume in the furnace 110. At the same time, the circulating bypass pipeline 350 can also play a role in dredging the main conveying pipeline 330 to prevent pressure buildup.

[0058] Under normal circumstances, the boiler flue gas treatment equipment includes a first air supply mechanism 500. The first air supply mechanism 500 can be connected to the secondary air nozzle 210, and the air-powder mixture is sent into the furnace 110. In this embodiment, the first air supply mechanism 500 can be connected to the secondary air nozzle 210 through a first branch pipeline, and the first air supply mechanism 500 is also connected to the first overfire air nozzle 410 through a second branch pipeline. The air rate of the overfire air mechanism 400 is 30%-40%.

[0059] It should be understood that in the prior art, the overfire air mechanism 400 only includes the first overfire air nozzle 410. Therefore, the air rate of the overfire air mechanism 400 in the total air volume required by the boiler is usually 20%-30%. However, in this embodiment, the second overfire air nozzle 420 can increase the air rate ratio of the overfire air mechanism 400, so that the air rate of the overfire air mechanism 400 in the total air volume required by the boiler is increased to 30%-40%. In this case, the air rate of the secondary air nozzle 210 in the total air volume required by the boiler is reduced. Therefore, the oxygen supplied to the main combustion zone by the secondary air in the main combustion zone is reduced, and the content of NO in the flue gas generated in the main combustion zone X will decrease accordingly. Although the unburned components in the flue gas will increase, due to the increase in the overfire air ejected by the overfire air mechanism 400 in the burnout zone, the increased unburned components can be correspondingly treated in the burnout zone. Generally speaking, this embodiment not only ensures the burnout rate of the unburned components but also further reduces the generation amount of NO X and significantly improves the cleanliness of the flue gas.

[0060] Combined with the foregoing, in order to enable the second overfire air nozzle 420 to eject high-speed air, the boiler flue gas treatment equipment may further include a second air supply mechanism 600. The second air supply mechanism 600 can be connected to the second overfire air nozzle 420 through the second overfire air duct. Of course, the output end of the second air supply mechanism 600 can also be directly connected to the second overfire air nozzle 420.

[0061] The boiler flue gas treatment equipment may further include a de-swirl mechanism. Based on this de-swirl mechanism, it can eliminate the residual rotation of the flue gas at the tail of the furnace 110, moderately reduce the radiant heat transfer in the furnace 110, and reduce the combustion flame from brushing against the furnace wall. This is beneficial to enhancing the convective heat transfer in the tail region, can effectively increase the load and improve the situation of low reheat steam temperature under rapid load change conditions, and achieve the effects of enhancing the combustion safety and economy of the boiler.

[0062] Based on the aforementioned boiler flue gas treatment equipment, the embodiment of the present application also discloses a boiler unit system, which includes the aforementioned boiler flue gas treatment equipment. Through this boiler flue gas treatment equipment, the boiler unit system can achieve full combustion and denitrification treatment of the internal flue gas and improve the cleanliness of the flue gas. In an alternative solution, the boiler unit system may further include an SCR (Selective Catalytic Reduction of flue gas denitrification) subsystem or an SNCR (Non-Selective Catalytic Reduction of flue gas denitrification) subsystem to further process the flue gas discharged from the boiler flue gas treatment equipment.

[0063] Certainly, the specific type of the boiler unit system in this embodiment is not limited. Specifically, it can be selected as a 330MW boiler unit system. Of course, it can also be selected as other types of boiler unit systems, such as a 300MW boiler unit system, a 450MW boiler unit system, etc.

[0064] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, and all of them fall within the protection scope of the present application.

Claims

1. A boiler flue gas treatment device, characterized in that, It includes a furnace body (100), a main burner mechanism (200), a reduction mechanism (300) and an overfire air mechanism (400). The furnace body (100) has a furnace chamber (110). The main burner mechanism (200), the reduction mechanism (300) and the overfire air mechanism (400) are arranged in sequence from bottom to top in the height direction of the furnace chamber (110). The main burner mechanism (200) includes a secondary air nozzle (210), and the secondary air nozzle (210) is oppositely arranged with respect to the combustion area of the main burner mechanism (200). The overfire air mechanism (400) includes a first overfire air nozzle (410) and a second overfire air nozzle (420). At least part of the first overfire air nozzle (410) is provided with an avoidance space (411), and the second overfire air nozzle (420) is arranged in the avoidance space (411). The overfire air velocity of the second overfire air nozzle (420) is greater than that of the first overfire air nozzle (410), and the second overfire air nozzle (420) is oppositely arranged with respect to the central area of the furnace chamber (110).

2. The boiler flue gas treatment equipment according to claim 1, characterized in that, The overfire air mechanism (400) includes a plurality of first overfire air nozzles (410). At least part of the plurality of first overfire air nozzles (410) is provided with the avoidance space (411), and the second overfire air nozzle (420) is arranged in the avoidance space (411).

3. The boiler flue gas treatment equipment according to claim 2, characterized in that, The plurality of first overfire air nozzles (410) are arranged in multiple groups along the circumferential direction in the furnace chamber (110). Each group of the first overfire air nozzles (410) is arranged in the height direction of the furnace chamber (110), and at least part of each group of the first overfire air nozzles (410) is provided with the avoidance space (411), and the second overfire air nozzle (420) is arranged in the avoidance space (411).

4. The boiler flue gas treatment equipment according to claim 1, characterized in that The reduction mechanism (300) includes a plurality of spraying elements (310). The plurality of spraying elements (310) are arranged on the inner furnace wall of the furnace body (100) and are arranged along the circumferential direction.

5. The boiler flue gas treatment equipment according to claim 4, characterized in that, The plurality of spraying elements (310) are arranged in multiple layers in the height direction of the furnace chamber (110), and two adjacent spraying elements (310) belonging to different layers are staggeredly distributed.

6. The boiler flue gas treatment equipment according to claim 4 or 5, characterized in that, The reduction mechanism (300) further includes a reductant supply source (320), a main conveying pipeline (330) and a pumping assembly (340). The reductant supply source (320) is connected to the plurality of spraying elements (310) through the main conveying pipeline (330), and the pumping assembly (340) is arranged on the main conveying pipeline (330). The reduction mechanism (300) further includes a circulating bypass pipeline (350). One end of the circulating bypass pipeline (350) is connected to the main conveying pipeline (330), and the other end of the circulating bypass pipeline (350) is connected to the reductant supply source (320).

7. The boiler flue gas treatment equipment according to claim 1, characterized in that, The boiler flue gas treatment equipment includes a first air supply mechanism (500). The first air supply mechanism (500) is connected to the secondary air nozzle (210) through a first branch pipeline, and the first air supply mechanism (500) is also connected to the first overfire air nozzle (410) through a second branch pipeline; the air rate of the overfire air mechanism (400) is 30%-40%.

8. A boiler unit system, characterized in that, It includes the boiler flue gas treatment equipment according to any one of the preceding claims 1 to 7.

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