Biomass boiler tail flue gas denitration and dust removal system

Abstract

The utility model relates to the technical field of flue gas treatment, in particular to a denitration and dust removal system for tail flue gas of a biomass boiler. The biomass boiler tail flue gas denitration and dust removal system comprises a biomass boiler body, the biomass boiler body comprises a tail vertical shaft flue, a first flue gas outlet is formed in the upper portion of the tail vertical shaft flue, and the first flue gas outlet is sequentially connected with a cyclone dust collector and a denitration and dust removal integrated device; an SCR catalyst thermal desorption device is arranged in the denitration and dust removal integrated device, the denitration and dust removal integrated device is further provided with a second flue gas outlet, the second flue gas outlet is connected with the lower portion of the tail vertical shaft flue, and a third flue gas outlet is formed in the bottom of the tail vertical shaft flue. According to the utility model, denitration and dust removal of the flue gas at the tail part of the biomass boiler are realized through two-step denitration and two-step dust removal.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas treatment, in particular to a denitration and dust removal system for the flue gas at the tail of a biomass boiler. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the overall understanding of the utility model, and it is not necessarily regarded as an admission or an indication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Biomass boilers using biomass as fuel utilize renewable agricultural and forestry residues to replace coal as boiler fuel, which can save conventional energy and optimize the energy structure. However, the composition of biomass fuel is relatively complex. In addition to containing conventional nitrogen oxides (NO x ), sulfur dioxide (SO2), and dust pollutants, the flue gas of biomass boilers also contains a large amount of sulfur trioxide (SO3), hydrogen chloride (HCl), hydrogen fluoride (HF), sodium (Na), potassium (K), and other pollutants. Therefore, effective denitration, desulfurization, and dust removal of biomass boiler flue gas are of great significance to environmental protection.

[0004] During the research process, it was found that the denitration of biomass boiler flue gas is a difficult problem in the treatment of biomass boiler flue gas. Traditional SNCR denitration (selective non-catalytic reduction) and SCR denitration (selective catalytic reduction) technologies cannot achieve good denitration effects. If the SCR denitration process is adopted, due to the relatively high mass fraction of alkali metals in the flue gas of biomass boilers, the SCR catalyst will be poisoned and deactivated by alkali metals within a short period of time (the engineering experience is at most no more than 3 months, and at least within 1 month); and since the SCR reactor is arranged in the tail flue of the biomass boiler, without dust removal, in addition to being poisoned and deactivated by alkali metals, the catalyst wear is also relatively serious. If the SNCR denitration process is adopted, due to the special structure of the biomass boiler, the overall furnace bed temperature is relatively low, generally between 700°C and 800°C, while the best temperature window for the SNCR denitration process is 850°C to 1050°C, so the SNCR temperature window is not suitable, resulting in very low efficiency. Therefore, how to achieve the denitration of biomass boiler flue gas is a technical problem that the biomass boiler industry urgently needs to solve. Summary of the Utility Model

[0005] In order to solve the above problems, the utility model provides a denitration and dust removal system for the flue gas at the tail of a biomass boiler.

[0006] To achieve the above technical objectives, the utility model adopts the following technical solutions:

[0007] A denitrification and dust removal system for the flue gas at the tail of a biomass boiler, comprising a biomass boiler body. The biomass boiler body includes a tail shaft flue. A first flue gas outlet is provided at the upper part of the tail shaft flue. The first flue gas outlet is sequentially connected to a cyclone dust collector and a denitrification and dust removal integrated device. An SCR catalyst thermal analysis device is arranged inside the denitrification and dust removal integrated device. The denitrification and dust removal integrated device is also provided with a second flue gas outlet, and the second flue gas outlet is connected to the lower part of the tail shaft flue. A third flue gas outlet is provided at the bottom of the tail shaft flue.

[0008] In one or more embodiments, the biomass boiler body further includes a furnace. The upper part of the furnace is communicated with the inlet of a cyclone separator. The cyclone separator is provided with a fourth flue gas outlet and a first ash conveying outlet. The fourth flue gas outlet is communicated with the upper part of the tail shaft flue. The first ash conveying outlet is communicated with the lower part of the furnace through a first ash conveying channel.

[0009] Preferably, the upper part of the furnace is communicated with the inlet of the cyclone separator through a horizontal flue, and an SNCR denitrification device is arranged at the inlet of the cyclone separator.

[0010] More preferably, the SNCR denitrification device includes a number of SNCR denitrification spray guns, and the air compression unit, the denitrifying agent unit and the dilution water unit are all connected to the SNCR denitrification spray guns through a distributor.

[0011] In one or more embodiments, the temperature of the flue gas at the first flue gas outlet is 230 - 250 °C, preferably 240 °C.

[0012] In one or more embodiments, the denitrification and dust removal integrated device includes a first flue gas inlet. The first flue gas inlet is communicated with a filter chamber through a first flue gas channel. The top of the filter chamber is communicated with a dust removal chamber. Filter bags are arranged around the dust removal chamber. A fifth flue gas outlet is provided at the top of the dust removal chamber.

[0013] Preferably, the filter bags adopt PTFE film coating, and the material of the filter bags is a high-temperature resistant filter material with surface treatment of ultra-fine fibers.

[0014] Preferably, a second ash conveying outlet is provided at the bottom of the filter chamber, and the second ash conveying outlet is connected to an ash bin through a second ash conveying channel.

[0015] Preferably, a first valve is arranged between the first flue gas channel and the filter chamber.

[0016] Preferably, the fifth flue gas outlet is connected to the inlet of the SCR reactor; the inlet of the SCR reactor is respectively connected to the inlets of multiple SCR reaction chambers; each SCR reaction chamber is connected to the outlet of the SCR reactor, and the outlet of the SCR reactor is connected to the second flue gas outlet.

[0017] More preferably, the structures of each SCR reaction chamber are the same, and a catalyst is loaded in the SCR reaction chamber.

[0018] Even more preferably, the effective catalytic temperature of the catalyst is 180 - 240 °C.

[0019] Even more preferably, a second valve is provided between the inlet of the SCR reactor and the inlet of the SCR reaction chamber; a third valve is provided between the SCR reaction chamber and the outlet of the SCR reactor, and a fourth valve is provided between the outlet of the SCR reactor and the second flue gas outlet.

[0020] In one or more embodiments, the SCR catalyst thermal desorption device includes a circulation pipeline, a heater and a circulation fan are provided on the circulation pipeline, and both ends of the circulation pipeline are respectively connected to the SCR reaction chamber.

[0021] In one or more embodiments, the third flue gas outlet is connected to an induced draft fan.

[0022] The beneficial effects of the present utility model are as follows:

[0023] (1) In the present utility model, denitrification and dust removal of the flue gas at the tail of the biomass boiler are achieved through two-step denitrification and two-step dust removal. Specifically, the denitrification process includes: when the flue gas in the furnace of the biomass boiler enters the cyclone separator, preliminary SNCR denitrification is first carried out at the inlet of the cyclone separator, and then the flue gas and the unreacted escaped ammonia in the SNCR denitrification process will enter the SCR reaction chamber of the denitrification and dust removal integrated device for deep denitrification, thereby achieving denitrification of the flue gas at the tail of the biomass boiler. The dust removal process includes: the flue gas in the tail shaft flue of the biomass boiler body first enters the cyclone dust collector for preliminary pre-dust removal, and the pre-dusted flue gas enters the dust removal chamber of the denitrification and dust removal integrated device for deep dust removal, thereby achieving dust removal of the flue gas at the tail of the biomass boiler.

[0024] (2) The pre-dusted flue gas enters the dust removal chamber of the denitrification and dust removal integrated device for deep dust removal and then enters the SCR reaction chamber for deep denitrification. By adopting a system of dust removal first and then denitrification, it can prevent the catalyst from deactivation and abrasion caused by too high dust concentration and reduce the service life of the catalyst.

[0025] (3) The denitration and dust removal integrated device is provided with multiple SCR reaction chambers. The compartmentalized setting can achieve the function of on-line maintenance. When the catalyst needs to be maintained, there is no need to stop the furnace. Only the valves for inlet and outlet flue gas of the SCR reaction chamber to be maintained need to be closed, and the SCR reaction chamber can be completely offline for maintenance. At the same time, the remaining SCR reaction chambers can continue to operate, ensuring denitration compliance without affecting the operation of the boiler.

[0026] (4) In the present utility model, multiple SCR reaction chambers share one SCR catalyst thermal desorption device, which can reduce the overall energy consumption. At the same time, when the catalyst in a certain SCR reaction chamber needs to be thermally desorbed, the valves for inlet and outlet flue gas of the SCR reaction chamber are closed. The SCR reaction chamber is connected to the SCR catalyst thermal desorption device, and the flue gas in the SCR reaction chamber is heated and circulated through a circulation fan and a heater. The heated flue gas circulates and scours the catalyst, vaporizing the ammonium bisulfate adhering to its surface, and realizing the recovery of the catalyst activity. At the same time, when thermally desorbing a certain SCR reaction chamber among the multiple compartmentalized SCR reaction chambers, there is no need to stop the furnace, and on-line thermal desorption can be achieved.

[0027] (5) The traditional SCR denitration device is to build a new SCR reactor on a separate steel frame after bag dust removal. However, for the denitration and dust removal integrated device provided by the present utility model, the SCR denitration device is directly placed inside the clean gas chamber of the bag filter, achieving the effect of collaborative denitration while having dust removal; so there is no need to build a new SCR reactor on a separate steel frame behind the bag dust removal. On the one hand, it reduces the floor area and makes the engineering site layout reasonable. On the other hand, it reduces the investment cost. This process has a two-in-one effect. Description of the Drawings

[0028] The specification drawings forming a part of the present utility model are used to provide a further understanding of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation of the present utility model.

[0029] Figure 1 It is the front view schematic diagram of the flue gas denitration and dust removal system at the tail of the biomass boiler;

[0030] Figure 2 It is the left view schematic diagram of the flue gas denitration and dust removal system at the tail of the biomass boiler;

[0031] Among them, 1-biomass boiler body, 2-furnace, 3-cyclone separator, 4-tail shaft flue, 5-SNCR denitration device, 5.1-SNCR denitration spray gun, 5.2-air compression unit, 5.3-denitration agent unit, 5.4-diluted water unit, 5.5-distributor, 6-first flue gas outlet, 7-first ash conveying outlet, 8-first ash conveying channel, 9-cyclone dust collector, 10-denitration and dust removal integrated device, 11-first flue gas inlet, 12-second flue gas outlet, 13-filter chamber, 14-second ash conveying outlet, 15-ash bunker, 16-SCR catalyst thermal desorption device, 16.1-heater, 16.2-circulation fan, 17-catalyst, 18-first flue gas channel, 19-dust removal chamber, 20-filter bag, 21-fifth flue gas outlet, 22-inlet of SCR reactor, 23-SCR reaction chamber, 24-outlet of SCR reactor, 25-induced draft fan, 26-third flue gas outlet. Detailed implementation manners

[0032] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0033] It should be noted that the terms used herein are only for describing the specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of the features, steps, operations, devices, components, and / or combinations thereof.

[0034] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are explanations of the present invention rather than limitations.

[0035] Embodiment 1

[0036] Refer to Figure 1 and Figure 2 , a denitration and dust removal system for the flue gas at the tail of a biomass boiler, comprising a biomass boiler body 1. The biomass boiler body 1 includes a tail shaft flue 4. A first flue gas outlet 6 is provided at the upper part of the tail shaft flue 4. The first flue gas outlet 6 is sequentially connected to a cyclone dust collector 9 and a denitration and dust removal integrated device 10. An SCR catalyst thermal desorption device 16 is arranged in the denitration and dust removal integrated device 10. A second flue gas outlet 12 is further provided in the denitration and dust removal integrated device 10. The second flue gas outlet 12 is connected to the lower part of the tail shaft flue 4. A third flue gas outlet 26 is provided at the bottom of the tail shaft flue 4.

[0037] Among them, the biomass boiler body 1 further includes a furnace 2. The upper part of the furnace 2 is connected to the inlet of the cyclone separator 3. The cyclone separator 3 is provided with a fourth flue gas outlet and a first ash conveying outlet 7. The fourth flue gas outlet is connected to the upper part of the tail shaft flue 4, and the first ash conveying outlet 7 is connected to the lower part of the furnace 2 through a first ash conveying channel 8. The flue gas generated in the furnace 2 first enters the cyclone separator 3. The cyclone separator 3 uses the cyclone effect to separate the solid particles in the gas-solid mixture and discharges the flue gas, achieving the effect of efficient flue gas separation.

[0038] In this embodiment, the upper part of the furnace 2 is connected to the inlet of the cyclone separator 3 through a horizontal flue, and an SNCR denitration device 5 is provided at the inlet of the cyclone separator 3. The SNCR denitration device includes three SNCR denitration spray guns 5.1. The air compression unit 5.2, the denitration agent unit 5.3, and the dilution water unit 5.4 are all connected to the SNCR denitration spray gun 5.1 through a distributor 5.5. The SNCR denitration device 5 provided at the inlet of the cyclone separator 3 can initially perform denitration.

[0039] In this embodiment, the denitration and dust removal integrated device 10 includes a first flue gas inlet 11 and 6 symmetrically arranged filter chambers 13 side by side. The first flue gas inlet 11 is connected to the filter chamber 13 through a first flue gas channel 18. The top of each filter chamber 13 is the same as the dust removal chamber 19, and filter bags 20 are arranged around the dust removal chamber 19; a fifth flue gas outlet 21 is provided at the top of the dust removal chamber 19. The flue gas enters the dust removal chamber 19 for dust removal, and the dust after dust removal will fall to the bottom of the filter chamber 13. Therefore, a second ash conveying outlet 14 is provided at the bottom of the filter chamber 13, and the second ash conveying outlet 14 is connected to the ash bin 15 through a second ash conveying channel.

[0040] Since the temperature of the flue gas at the first flue gas outlet is 230 - 250 °C, in order to improve the service life of the filter bag 20, in this embodiment, the filter bag is made of PTFE film, and the material of the filter bag is a high-temperature resistant filter material with surface treatment of ultrafine fibers.

[0041] In order to better control the inlet and outlet of the flue gas, a first valve is provided between the first flue gas channel 18 and the filter chamber 13.

[0042] The fifth flue gas outlet 21 provided at the top of the dust removal chamber 19 is communicated with the inlet 22 of the SCR reactor; the inlet 22 of the SCR reactor is respectively connected to the inlets of a plurality of SCR reaction chambers 23; each SCR reaction chamber 23 is communicated with the outlet 24 of the SCR reactor, and the outlet 24 of the SCR reactor is communicated with the second flue gas outlet 12. In this embodiment, a total of 5 SCR reaction chambers 23 are provided. The structure of each SCR reaction chamber 23 is the same, and a catalyst 17 is loaded in each SCR reaction chamber. Since the temperature of the flue gas at the first flue gas outlet is 230-250°C and the temperature will decrease to a certain extent during the flow process, the effective catalytic temperature of the catalyst defined in this embodiment is 180-240°C.

[0043] In order to better control the flow of the flue gas in the denitration and dust removal integrated device 10, a second valve is provided between the inlet 22 of the SCR reactor and the inlet of the SCR reaction chamber 23; a third valve is provided between the SCR reaction chamber 23 and the outlet 24 of the SCR reactor, and a fourth valve is provided between the outlet 24 of the SCR reactor and the second flue gas outlet 12.

[0044] Since ammonium bisulfate will adhere to the surface of the catalyst during use, which in turn deactivates the catalyst, in order to restore the activity of the catalyst, an SCR catalyst thermal desorption device 16 is provided in the denitration and dust removal integrated device 10. The SCR catalyst thermal desorption device 16 includes a circulation pipeline, and a heater 16.1 and a circulation fan 16.2 are provided on the circulation pipeline. The main pipelines A and B on both sides of the circulation pipeline are each divided into 5 branch pipelines, which are respectively communicated with 5 SCR reaction chambers. The main pipeline B of the circulation pipeline is connected to the pipeline at the second flue gas outlet through a fifth valve.

[0045] The third flue gas outlet 26 is connected to the induced draft fan 25, and the clean flue gas returns to the lower part of the tail shaft flue 4 and is discharged into the atmosphere through the induced draft fan 25.

[0046] The working process of the biomass boiler tail flue gas denitration and dust removal system is as follows:

[0047] Biomass fuel is burned in the furnace of the biomass boiler body, and a large amount of flue gas is generated during the combustion process. The flue gas first enters the cyclone separator through the horizontal flue. The SNCR denitration device provided at the inlet of the cyclone separator can initially carry out denitration; the cyclone separator uses the cyclone action to separate the solid particles in the gas-solid mixture and discharge the flue gas, achieving the effect of highly separating the flue gas.

[0048] The flue gas discharged from the cyclone separator enters the cyclone dust collector through the first flue gas outlet. The cyclone separator generates centrifugal force during rotation, throwing dust particles with a density greater than that of the gas towards the cylinder wall, thereby removing large particulate dust and sparks and achieving the effect of preliminary dust removal.

[0049] The flue gas after preliminary dust removal enters the denitration and dust removal integrated device for in-depth denitration and dust removal. Specifically, the flue gas after preliminary dust removal enters the first flue gas inlet, then is added to each filter chamber through the first flue gas channel, and then enters the dust removal chamber. Under the action of the filter bags in the dust removal chamber, in-depth dust removal is carried out. The dust after dust removal will fall to the bottom of the filter chamber and enter the second ash conveying channel through the second ash outlet at the bottom of the filter chamber and is then transported to the ash bunker. The flue gas after dust removal enters the inlet of the SCR reactor through the fifth flue gas outlet set at the top of the dust removal chamber, and then enters each SCR reaction chamber. Under the action of the catalyst in the SCR reaction chamber, it reacts with the escaped ammonia that did not react during the SNCR denitration process for in-depth denitration. The flue gas after denitration returns to the lower part of the tail shaft flue from the second flue gas outlet and is discharged into the chimney and the atmosphere through the induced draft fan.

[0050] Since ammonium bisulfate will adhere to the surface of the catalyst during use, causing the catalyst to deactivate, the denitration and dust removal integrated device is used to thermally desorb and revive the catalyst in each SCR reaction chamber. During the thermal desorption process, the first valve between the first flue gas channel and the filter chamber is closed, the second valve between the inlet of the SCR reactor and the inlet of the SCR reaction chamber is closed, the third valve between the SCR reaction chamber and the outlet of the SCR reactor is closed, and the branch pipeline between the SCR reaction chamber and the SCR catalyst thermal desorption device forms a circulation pipeline. The flue gas after dust removal in the SCR reaction chamber is used as the circulating flue gas. Under the action of the heater and the circulation fan, the heated flue gas circulates to scour the catalyst, making the ammonium bisulfate adhered to its surface vaporize, realizing the recovery of the catalyst activity. If the temperature of the heated flue gas is too high, the fifth valve on the main pipeline of the circulation pipeline B can be opened, and the clean flue gas discharged from the second flue gas outlet is sucked into the circulation pipeline by the circulation fan (the pressure of the circulation fan for thermal desorption is higher than the negative pressure of the induced draft fan). After the temperature drops to the set temperature, the fifth valve is closed. When the catalyst activity is restored, the fifth valve is opened to discharge the flue gas in the SCR reaction chamber.

[0051] Furthermore, if there is a problem with a certain SCR reaction chamber, the first valve between the first flue gas channel and the filter chamber is closed, the second valve between the inlet of the SCR reactor and the inlet of the SCR reaction chamber is closed, and the third valve between the SCR reaction chamber and the outlet of the SCR reactor is closed, and then maintenance can be carried out.

[0052] In the present utility model, denitration and dust removal of the flue gas at the tail of the biomass boiler are achieved through two-step denitration and two-step dust removal. The flue gas after preliminary dust removal enters the dust removal chamber of the denitration and dust removal integrated device for in-depth dust removal and then enters the SCR reaction chamber for in-depth denitration. By adopting a system of dust removal first and then denitration, it can prevent the deactivation and abrasion of the catalyst caused by too high dust concentration and reduce the service life of the catalyst. The denitration and dust removal integrated device is provided with multiple SCR reaction chambers. The compartmentalized setting can realize the function of online maintenance. When the catalyst needs to be maintained, there is no need to stop the furnace. Only the valves for the inlet and outlet flue gas of the SCR reaction chamber to be maintained need to be closed, and the SCR reaction chamber can be completely offline for maintenance. At the same time, the remaining SCR reaction chambers can continue to operate, ensuring denitration compliance without affecting the operation of the boiler. In the present utility model, multiple SCR reaction chambers share one SCR catalyst thermal desorption device, which can reduce the overall energy consumption. At the same time, when the catalyst in a certain SCR reaction chamber needs to be thermally desorbed, the valves for the inlet and outlet flue gas of the SCR reaction chamber are closed. The SCR reaction chamber is connected to the SCR catalyst thermal desorption device, and the flue gas in the SCR reaction chamber is heated and circulated by a circulation fan and a heater. The heated flue gas circulates and scours the catalyst, vaporizing the ammonium bisulfate adhering to its surface, and realizing the recovery of the activity of the catalyst. At the same time, when thermally desorbing a certain SCR reaction chamber among the compartmentalized multiple SCR reaction chambers, there is no need to stop the furnace, and online thermal desorption can be realized.

[0053] Finally, it should be noted that the above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent substitution on some of them. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A biomass boiler tail flue gas denitrification and dust removal system, characterized in that: It includes a biomass boiler body, which includes a tail shaft flue, a first flue gas outlet is arranged at the upper part of the tail shaft flue, the first flue gas outlet is connected to a cyclone dust collector and a denitrification and dust removal integrated device in sequence, an SCR catalyst thermal analysis device is arranged in the denitrification and dust removal integrated device, the denitrification and dust removal integrated device is also provided with a second flue gas outlet, the second flue gas outlet is connected to the lower part of the tail shaft flue, and a third flue gas outlet is arranged at the bottom of the tail shaft flue.

2. The biomass boiler tail flue gas denitrification and dust removal system according to claim 1, characterized in that: The biomass boiler body also includes a furnace, the upper part of which is connected to the inlet of a cyclone separator. The cyclone separator is provided with a fourth flue gas outlet and a first ash outlet. The fourth flue gas outlet is connected to the upper part of the tail shaft flue, and the first ash outlet is connected to the lower part of the furnace through a first ash conveying channel.

3. The biomass boiler tail flue gas denitrification and dust removal system according to claim 2, characterized in that: The upper part of the furnace is connected to the inlet of the cyclone separator through a horizontal flue, and an SNCR denitrification device is provided at the inlet of the cyclone separator; The SNCR denitration device comprises a plurality of SNCR denitration spray guns, and an air compression unit, a denitration agent unit and a dilution water unit are all connected to the SNCR denitration spray guns through a distributor.

4. The biomass boiler tail flue gas denitrification and dust removal system according to claim 1, characterized in that: The integrated denitrification and dust removal device includes a first flue gas inlet, which is connected to the filter chamber through a first flue gas channel. The top of the filter chamber is connected to the dust removal chamber, and filter bags are arranged around the dust removal chamber; a fifth flue gas outlet is arranged on the top of the dust removal chamber.

5. The biomass boiler tail flue gas denitrification and dust removal system according to claim 4, characterized in that: A second ash delivery outlet is provided at the bottom of the filter chamber, and the second ash delivery outlet is connected to the ash bin through a second ash delivery channel; Alternatively, a first valve is provided between the first smoke channel and the filter chamber.

6. The biomass boiler tail flue gas denitrification and dust removal system according to claim 4, characterized in that: The fifth flue gas outlet is connected to the inlet of the SCR reactor; the inlet of the SCR reactor is respectively connected to multiple SCR reaction chamber inlets; each SCR reaction chamber is connected to the outlet of the SCR reactor, and the outlet of the SCR reactor is connected to the second flue gas outlet.

7. The biomass boiler tail flue gas denitrification and dust removal system according to claim 6, characterized in that: Each SCR reaction chamber has the same structure, and a catalyst is loaded in the SCR reaction chamber.

8. The biomass boiler tail flue gas denitrification and dust removal system according to claim 6, characterized in that: A second valve is provided between the inlet of the SCR reactor and the inlet of the SCR reaction chamber; a third valve is provided between the SCR reaction chamber and the outlet of the SCR reactor; and a fourth valve is provided between the outlet of the SCR reactor and the second flue gas outlet.

9. The biomass boiler tail flue gas denitrification and dust removal system according to claim 1, characterized in that: The SCR catalyst thermal desorption device comprises a circulation pipeline, on which a heater and a circulation fan are arranged, and both ends of the circulation pipeline are respectively connected to the SCR reaction chamber.

10. The biomass boiler tail flue gas denitrification and dust removal system according to claim 1, characterized in that: The third smoke outlet is connected to the induced draft fan.

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