SCR (Selective Catalytic Reduction) denitration system for biomass boiler flue gas

Abstract

The invention discloses an SCR denitration system for biomass boiler flue gas, and belongs to the technical field of SCR denitration, the SCR denitration system comprises an SCR denitration device, a flue gas diversion pipeline, a diversion mechanism and a detection mechanism, the SCR denitration device comprises a reactor body and a plurality of groups of catalyst modules arranged in the reactor body; the flue gas guide pipeline is respectively communicated with the economizer and the gas inlet end of the reactor body; the detection mechanisms comprise a plurality of groups of flow guide mechanisms, and each group of flow guide mechanism is positioned above the corresponding catalyst module and is used for guiding, regulating and controlling the flow direction and the flow rate of the biomass boiler flue gas; each detection mechanism is located between the corresponding catalyst module and the flow guide mechanism, and the detection mechanisms are used for monitoring the flow speed and distribution of the biomass boiler flue gas flowing through the catalyst modules. The flue gas flow of the biomass boiler can be accurately controlled, uniform distribution of the flue gas of the biomass boiler in the catalyst module is ensured, the service life of an SCR denitration catalyst is prolonged, and the working efficiency of the SCR denitration catalyst is improved.

Description

Technical Field

[0001] The invention relates to the technical field of SCR denitration, and in particular to an SCR denitration system for biomass boiler flue gas. Background Art

[0002] SCR denitrification technology, namely selective catalytic reduction (SCR for short), is a highly efficient biomass boiler flue gas purification method. This technology injects ammonia or a suitable reducing agent into the flue gas of the biomass boiler at the front end of the catalyst, and uses a catalyst containing elements such as iron, vanadium, chromium, cobalt, and molybdenum to reduce nitrogen oxides (NO x ) is catalytically converted into harmless nitrogen and water. However, in actual use, the catalysts inside traditional SCR denitration reactors are mostly fixed. In this case, the utilization of catalysts in different areas is likely to vary greatly, which can easily lead to waste.

[0003] Chinese Patent 202011010488.8 discloses an SCR denitration reactor, including a shell, an air intake mechanism, an emission mechanism, a reactor body, a catalytic mechanism, a motor, a connecting rod, a fixed block, a spring, a clamping rod, a fixed plate, a wire cage, a shaking mechanism, a slider, a pressure block and an extrusion block. The device drives the extrusion block to rotate simultaneously through the rotation of the mesh frame. When the extrusion block rotates to the position of the pressure block, the extrusion block will be forced to move, thereby driving the mesh frame to move, and the above operation is repeated continuously, so that the catalyst can be conveniently screened during use, thereby avoiding large differences in the utilization of catalysts in different areas and reducing the phenomenon of catalyst waste. Although the above-mentioned SCR denitration reactor drives the catalyst to rotate by the mesh frame, which effectively reduces the consumption of the catalyst, it still faces several key challenges in industrial practical applications. Specifically, although the biomass boiler flue gas has been initially guided by the guide plate before entering the reactor body, the dynamic fluctuations in the production process or the adjustment of process parameters often lead to non-steady-state changes in the biomass boiler flue gas flow rate, which in turn causes uneven distribution of the biomass boiler flue gas inside the reactor. This uneven distribution of biomass boiler flue gas can easily lead to abnormal increases in local flow velocity, aggravating the wear effect of fly ash particles on the catalyst surface and significantly shortening the effective service life of the catalyst.

[0004] In addition, during the catalytic conversion of the catalyst and biomass boiler flue gas, the distribution characteristics of the biomass boiler flue gas flow field have an important influence on the catalytic performance. In particular, with the increase of the biomass boiler flue gas flow rate, the same mass of fly ash particles will obtain greater kinetic energy. When these particles collide with the bottom of the catalyst, the erosion effect on the catalyst will be significantly enhanced, thereby reducing the catalytic conversion efficiency of the biomass boiler flue gas. When the bottom of the catalyst is severely eroded, it may cause the overall destruction of the catalyst layer structure, that is, the collapse of the catalyst layer. If necessary, it is necessary to stop production for replacement and maintenance. At the same time, the increase in the concentration of biomass boiler flue gas directly leads to a corresponding increase in the fly ash content. With the continuous operation of the denitrification system, fly ash particles gradually deposit on the catalyst surface, forming a pore blockage phenomenon, thereby reducing the effective channel area for the airflow. This change forces the biomass boiler flue gas to pass through the unblocked pores at a higher flow rate, increasing the mechanical stress on the inner wall of the catalyst pore, further exacerbating the wear and potential collapse risk of the catalyst. Summary of the invention

[0005] Technical problems to be solved: In view of the technical problems existing in the background technology, the present invention provides an SCR denitrification system for biomass boiler flue gas. The SCR denitrification catalyst adopts a rare earth coupled modified catalyst with resistance to alkali metal poisoning, and detects the airflow distribution of the biomass boiler flue gas when entering the catalyst module through a detection mechanism. The operating state of the guide mechanism is dynamically adjusted according to the detection result to achieve precise control of the biomass boiler flue gas flow rate, thereby ensuring the uniform distribution of the biomass boiler flue gas inside the catalyst module and improving the service life and working efficiency of the SCR denitrification catalyst.

[0006] Technical solution: The SCR denitration system for biomass boiler flue gas described in the present invention comprises: An SCR denitration device, the SCR denitration device comprising a reactor body having an air inlet end and an air outlet end, wherein a plurality of catalyst modules are layered in the reactor body along its height direction; A flue gas guide duct, one end of which is connected to the economizer, and the other end of which is connected to the air inlet end of the reactor body. The flue gas of the biomass boiler enters the reactor body from the economizer through the flue gas guide duct and reacts with the multi-layer catalyst module. A flow guiding mechanism, wherein the flow guiding mechanism comprises a plurality of groups arranged along the height direction of the reactor body, each group of the flow guiding mechanism is located above its corresponding catalyst module, and is used to guide and regulate the flow direction and flow rate of the flue gas from the biomass boiler; The detection mechanism includes a plurality of groups arranged along the height direction of the reactor body, each group of the detection mechanism is located between its corresponding catalyst module and the guide mechanism, and the detection mechanism is used to monitor the flow rate and distribution of the biomass boiler flue gas flowing through the catalyst module.

[0007] Preferably, the flow guiding mechanism comprises: A flow guide frame, wherein the flow guide frame is horizontally arranged in the reactor body; The guide plate includes a plurality of groups of guide plates distributed in a parallel array along the inside of a guide frame, and the guide plate includes a guide shaft and guide wing plates symmetrically distributed along both sides of the guide shaft; a deflection mechanism is provided at the connection between the two ends of the guide shaft and the guide frame, and the deflection mechanism is used to drive the guide plate to deflect back and forth along the guide frame, so as to control the flow path of the flue gas of the biomass boiler.

[0008] Preferably, the deflection mechanism comprises mounting grooves correspondingly arranged at both ends of the guide shaft body, and an arc groove is arranged on the inner wall of the mounting groove in the circumferential direction; Pushing members are correspondingly arranged on the two side walls of the guide frame, and a mounting shaft is arranged at one inner end of the pushing member. The mounting shaft is correspondingly clamped in the mounting groove, and a limiting protrusion slidably connected to the arc groove is arranged on the side wall of the mounting shaft; The pushing member drives the installation shaft to rotate, and the limiting protrusion squeezes the arc groove to drive the guide plate to deflect and adjust the guide angle.

[0009] Preferably, the detection mechanism comprises: A detection frame, the detection frame is horizontally arranged in the reactor body, and the detection frame is provided with mounting frame slots distributed in an array; The movable plate includes a plurality of blocks correspondingly arranged in the slot holes of the mounting frame; the movable plate is connected to the inner side wall of the slot hole of the mounting frame through a plurality of elastic members arranged around the movable plate. When the smoke from the biomass boiler impacts the movable plate, the expansion and contraction amount of the elastic members reflects the impact force of the smoke from the biomass boiler on the movable plate.

[0010] Preferably, a partition plate is vertically arranged in the center of the reactor body, and the partition plate divides the reactor body into two equal areas; The flow guiding mechanism, the detection mechanism and the catalyst module arranged in the reactor body are distributed in a mirror image with the partition plate as the center line.

[0011] Preferably, the partition plate is provided with first through holes and second through holes distributed in an array; A control valve is provided inside the first through hole, and the first through hole is correspondingly arranged between the flow guiding mechanism and the detection mechanism; A control valve is arranged inside the second through hole, and the second through hole is correspondingly arranged between the catalyst module and the flow guiding mechanism.

[0012] Preferably, an ammonia spraying grid is radially arranged in the flue gas guide duct, the ammonia spraying grid is connected to an ammonia spraying component arranged outside the flue gas guide duct, and the ammonia spraying component sprays ammonia into the flue gas guide duct through the ammonia spraying grid.

[0013] Preferably, the ammonia spraying assembly comprises a fan, a heater, an evaporator and a gas mixer; the fan has an air inlet and an air outlet, and is used to dilute the ammonia sprayed into the flue gas guide duct; the heater is connected to the air outlet of the fan, and the heater heats the air mixed with the ammonia; the evaporator is connected to an external liquid ammonia tank, and the evaporator is used to heat the liquid ammonia to evaporate it; one end of the gas mixer is connected to the evaporator, and the other end is connected to the ammonia spraying grid, and the gas mixer is used to mix and heat the air and ammonia.

[0014] Preferably, the ammonia injection grids are arranged in a plurality of groups in an array along the flue gas guide duct, and a height difference is provided between two adjacent ammonia injection grids.

[0015] Preferably, a static mixer is provided on the side of the ammonia injection grid close to the SCR denitrification device, and a plurality of vanes are distributed in an array in the static mixer, and the vanes are used to increase gas disturbance and accelerate the mixing of ammonia and biomass boiler flue gas.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The SCR denitration catalyst of the present invention adopts a rare earth coupled modified catalyst with resistance to alkali metal poisoning, thereby improving the resistance to alkali metal poisoning of the SCR denitration catalyst and improving the service life and working efficiency of the SCR denitration catalyst.

[0017] 2. The detection mechanism monitors the change in the expansion and contraction of the elastic part connected to the movable plate in the slot of the mounting frame to determine the distribution of the biomass boiler flue gas when it passes through the detection mechanism and enters the catalyst module. The deflection angle of the guide plate is dynamically adjusted according to the detection result, thereby achieving precise control of the biomass boiler flue gas flow rate, thereby ensuring the uniform distribution of the biomass boiler flue gas inside the catalyst module. Compared with the existing technology, the device improves the catalytic efficiency, extends the service life of the catalyst, and optimizes the performance of the entire biomass boiler flue gas treatment system.

[0018] 3. The guide mechanism can control the rotation direction of each guide plate by controlling the deflection mechanism, thereby controlling the flow of biomass boiler flue gas through the guide mechanism, and realizes intelligent regulation of the flow of biomass boiler flue gas flowing through the guide mechanism through the coordinated action of the guide plate and the detection mechanism; when the control system detects that the catalyst module is blocked, the deflection guide plate can be used to quickly adjust the flow of biomass boiler flue gas entering various areas of the reactor body, thereby avoiding further deterioration of the catalyst module blockage area; ensuring that the biomass boiler flue gas can pass through the catalyst module evenly and efficiently, thereby improving the efficiency and stability of the catalytic reduction reaction.

[0019] 4. When the catalyst module is blocked, the deflection of the guide plate not only adjusts the flue gas flow of the biomass boiler, but also physically cleans the blocked part of the catalyst module by impacting the movable plate in a pulsed manner. This cleaning method avoids the problem of reduced catalytic reduction effect of the catalyst due to blockage and effectively extends the service life of the catalyst. At the same time, by precisely controlling the deflection angle and frequency of the guide plate, accurate blowing or striking of the blocked area can be achieved, improving cleaning efficiency and accuracy.

[0020] 5. When the control system detects that the catalyst module may be over-eroded, the deflection guide plate can quickly block the original flow path of the biomass boiler flue gas and isolate the affected catalyst module. This isolation measure prevents the biomass boiler flue gas from failing to effectively react when passing through the damaged catalyst module and affecting the overall reaction effect of other biomass boiler flue gases. At the same time, by adjusting the flow path of the biomass boiler flue gas, the distribution of the biomass boiler flue gas in various areas can be optimized, reducing the load of the catalyst module in a specific area, thereby preventing the occurrence of excessive erosion.

[0021] The present invention also has other beneficial effects which are described in the embodiments of the specification and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the process of the biomass boiler flue gas SCR denitrification system according to an embodiment of the present invention; Figure 2 for Figure 1 Schematic diagram of the three-dimensional structure of the SCR denitrification device; Figure 3 for Figure 2 Schematic diagram of the internal structure of the reactor body; Figure 4 for Figure 2 Schematic diagram of the structure of the partition plate of the reactor body; Figure 5 for Figure 3 Schematic diagram of the three-dimensional structure of the detection mechanism; Figure 6for Figure 3 Schematic diagram of the three-dimensional structure of the middle flow guide mechanism; Figure 7 for Figure 6 Schematic diagram of the structure of the middle guide plate and its two ends; Figure 8 for Figure 7 A cross-sectional view of the middle guide plate along its axial structure; Fig. 9 for Figure 8 The enlarged structural diagram at A in the middle; Fig.10 for Figure 2 Schematic diagram of the state of the SCR denitration device when it is working normally; Fig.11 for Fig.10 Schematic diagram of the first working state of the SCR denitration device; Fig.12 for Fig.10 Schematic diagram of the second working state of the SCR denitration device; Fig.13 for Fig.10 Schematic diagram of the third working state of the SCR denitrification device.

[0023] Reference numerals: 100, economizer; 200, flue gas guide duct; 300, static mixer; 400, ammonia injection grid; 500, ammonia injection assembly; 5001, fan; 5002, heater; 5003, evaporator; 5004, gas mixer; 1. SCR denitration device; 101. Reactor body; 102. Air inlet end; 103. Air outlet end; 104. Catalyst module; 2. Partition plate; 201. First through hole; 202. Second through hole; 3. Guide mechanism; 301. Guide frame; 302. Guide plate; 303. Guide shaft; 304. Guide wing; 4. Deflection mechanism; 401. Pusher; 402. Mounting shaft; 403. Limiting protrusion; 404. Mounting groove; 405. Arc groove; 5. Detection mechanism; 501. Detection frame; 502. Movable plate; 503. Elastic member; 504. Mounting frame slot. DETAILED DESCRIPTION

[0024] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the following will be combined with the attached Figures 1 to 13 The technical solutions of the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0025] Example 1: During the SCR catalyst denitrification process, the flue gas from the biomass boiler will produce certain dynamic fluctuations when entering the reactor body, resulting in non-steady-state changes in the flue gas flow rate, which in turn causes uneven distribution of the flue gas inside the reactor. This uneven flue gas distribution can easily lead to abnormal increases in local flow rates, exacerbating the wear effect of fly ash particles on the catalyst surface, resulting in a decrease in the catalytic activity of the catalyst, thereby affecting the catalytic effect. Figures 1 to 4 As shown, an SCR denitration system for biomass boiler flue gas of the present invention comprises an SCR denitration device 1, a flue gas diversion duct 200, a diversion mechanism 3 and a detection mechanism 5. The SCR denitration device 1 comprises a reactor body 101 having an air inlet end 102 and an air outlet end 103, wherein a plurality of groups of catalyst modules 104 are arranged in layers along the height direction of the reactor body 101; the biomass boiler flue gas enters the reactor body 101 from the air inlet end 102, and undergoes a catalytic reaction with the catalyst modules 104 therein, and is finally discharged from the air outlet end 103.

[0026] One end of the flue gas guide pipe 200 is connected to the economizer 100, and the other end thereof is connected to the air inlet end 102 of the reactor body 101. The flue gas of the biomass boiler enters the reactor body 101 from the economizer 100 through the flue gas guide pipe 200, and reacts with the multi-layer catalyst module 104. In the reactor body 101, the flue gas of the biomass boiler passes through the catalytic action of the catalyst module 104, and ammonia reacts with nitrogen oxides in the flue gas of the biomass boiler to generate harmless nitrogen and water, thereby achieving effective removal of nitrogen oxides in the flue gas of the biomass boiler.

[0027] like Figures 2~4 As shown, the flow guiding mechanism 3 includes multiple groups arranged along the height direction of the reactor body, and each group of flow guiding mechanism 3 is located above its corresponding catalyst module 104, and is used to guide and regulate the flow direction and flow rate of the flue gas of the biomass boiler.

[0028] like Figure 6-7 As shown, the guide mechanism 3 includes a guide frame 301 and a guide plate 302. The guide frame 301 is horizontally arranged in the reactor body 101. The guide plate 302 includes multiple groups distributed in a parallel array along the inside of the guide frame 301. The guide plate 302 includes a guide shaft 303 and guide wing plates 304 symmetrically distributed along both sides of the guide shaft 303. A deflection mechanism 4 is provided at the connection between the two ends of the guide shaft 303 and the guide frame 301. The deflection mechanism 4 is used to drive the guide plate 302 to reciprocate along the guide frame 301 to control the flow path of the biomass boiler flue gas. In the process of driving the guide plate 302 to rotate, the deflection mechanism 4 simultaneously changes the flow direction of the biomass boiler flue gas, so that the biomass boiler flue gas is more evenly distributed above the catalyst module 104.

[0029] like Figures 8 and 9 As shown, the deflection mechanism 4 includes mounting grooves 404 correspondingly arranged at both ends of the guide shaft body 303, and the inner wall of the mounting groove 404 is provided with an arc groove 405 in the circumferential direction. Pushing members 401 are correspondingly arranged on the two side walls of the guide frame, and a mounting shaft 402 is arranged at one inner end of the pushing member 401. The mounting shaft 402 is correspondingly clamped in the mounting groove 404, and a limiting protrusion 403 slidably connected to the arc groove 405 is arranged on the side wall of the mounting shaft 402; during the process of driving the mounting shaft 402 to rotate by the pushing member 401, the arc groove 405 is squeezed by the limiting protrusion 403 to drive the guide plate 302 to deflect and adjust the guide angle. During operation, when the pusher 401 extends inward, the limiting protrusion 403 on the mounting shaft 402 slides in the arc groove 405, and squeezes and forces the guide plate 302 to deflect to the left; when the pusher 401 contracts outward, the limiting protrusion 403 on the mounting shaft 402 slides along the arc groove 405, and reversely squeezes and forces the guide plate 302 to deflect to the right, thereby achieving positive or reverse angle adjustment of the guide plate 302. It should be noted that a driving mechanism is provided on the outer side corresponding to the guide mechanism 3 and the deflection mechanism 4, and the driving mechanism can be a driving cylinder or a hydraulic cylinder, and the driving mechanism drives the multiple pushers 401 provided on one side to move inward or outward along their axial direction, thereby driving the pushers 401.

[0030] like Figure 3~4 As shown, the detection mechanism 5 includes multiple groups arranged along the height direction of the reactor body, each group of detection mechanism 5 is located between its corresponding catalyst module 104 and the guide mechanism 3, and the detection mechanism 5 is used to monitor the flow rate and distribution of the biomass boiler flue gas flowing through the catalyst module 104.

[0031] Specifically, Figure 5As shown, the detection mechanism 5 includes a detection frame 501 and a movable plate 502. The detection frame 501 is horizontally arranged in the reactor body 101, and the detection frame 501 is provided with array-distributed mounting frame slots. The movable plate 502 includes a plurality of blocks correspondingly arranged in the mounting frame slots 504. The movable plate 502 is connected to the inner side wall of the mounting frame slots 504 through a plurality of elastic members 503 arranged around it. When the flue gas of the biomass boiler impacts the movable plate 502, the expansion and contraction amount of the elastic member 503 reflects the impact strength of the flue gas of the biomass boiler on the movable plate 502. The elastic member 503 can be a spring, one end of the spring is connected to the inner side wall of the detection frame 501, and the other end of the spring is connected to the side wall of the movable plate 502. A pressure sensor is provided at the connection between the spring and the detection frame 501, and the pressure sensor is used to detect the expansion and contraction amount of the elastic member 503. During operation, after the biomass boiler flue gas enters the reactor body 101 through the air inlet end 102, before the biomass boiler flue gas contacts and reacts with each layer of the catalyst module 104 inside the reactor body 101, it first enters the detection mechanism 5 after being guided by the guide mechanism 3. The detection mechanism 5 detects the flow rate of the biomass boiler flue gas and diverts it, so that the biomass boiler flue gas can enter the catalyst module 104 in a uniform manner.

[0032] When the catalyst module is blocked, the deflection of the guide plate not only adjusts the flue gas flow of the biomass boiler, but also physically cleans the blocked part of the catalyst module by impacting the movable plate in a pulsed manner. This cleaning method avoids the problem of reduced catalytic reduction effect of the catalyst caused by blockage and effectively extends the service life of the catalyst. At the same time, by precisely controlling the deflection angle and frequency of the guide plate, accurate blowing or striking of the blocked area can be achieved, improving cleaning efficiency and accuracy.

[0033] It should be noted that a control terminal is disposed outside the reactor body 101 , and a control system is disposed inside the control terminal. The control system is used to control the movement of electrical components inside the reactor body 101 .

[0034] In the initial state, the deflection angles of the guide plates 302 arranged inside the reactor body 101 are all in a fixed state. The control system can determine whether the distribution of the biomass boiler flue gas is uniform when it enters the catalyst module 104 through the detection mechanism 5 by monitoring the expansion and contraction of the elastic member 503 inside the mounting frame slot 504. During operation, the control system can control the rotation direction of each guide plate by controlling the deflection mechanism, thereby controlling the flow of the biomass boiler flue gas through the guide mechanism, and realizing intelligent regulation of the flow of the biomass boiler flue gas flowing through the guide mechanism through the synergistic effect of the guide plate and the detection mechanism; when the control system detects that the catalyst module is blocked, the flow of the biomass boiler flue gas entering each area of ​​the reactor body can be quickly adjusted by deflecting the guide plate, thereby avoiding further deterioration of the blocked area of ​​the catalyst module; ensuring that the biomass boiler flue gas can pass through the catalyst module evenly and efficiently, thereby improving the efficiency and stability of the catalytic reduction reaction.

[0035] When the control system detects that the difference between the expansion and contraction amounts of the elastic members 503 distributed on a single detection frame 501 is in a stable state, it indicates that the incoming biomass boiler flue gas is evenly distributed after being guided by the guide mechanism 3, so that when the biomass boiler flue gas enters the catalyst module 104 through the detection mechanism 5, when the biomass boiler flue gas in different areas impacts the corresponding movable plate 502, the forces exerted on each movable plate 502 on the detection frame 501 are basically the same, thereby making the difference between the expansion and contraction amounts of the elastic members 503 in a stable state. At this time, the guide mechanism 3 maintains its original state, that is, the deflection angle of the guide plate 302 remains unchanged, such as Fig.10 The first working state of the SCR denitrification device is shown.

[0036] When the control system detects that the difference between the expansion and contraction amounts of the elastic members 503 distributed on a single detection frame 501 exceeds the set value, it indicates that due to actual production needs, the biomass boiler flue gas has a certain dynamic fluctuation after entering the reactor body, which causes the biomass boiler flue gas to be unevenly distributed after being guided by the guide mechanism 3, so that when the biomass boiler flue gas enters the catalyst module 104 through the detection mechanism 5, the biomass boiler flue gas in different areas impacts the corresponding movable plate 502, and the forces received by each movable plate 502 on the detection frame 501 are not the same, so that the difference between the expansion and contraction amounts of the elastic members 503 exceeds the set value. When the control system detects that the difference between the expansion and contraction amounts of each elastic member 503 on a single detection frame 501 exceeds the set value, the control system dynamically adjusts the deflection angle of the corresponding guide plate 302 according to the expansion and contraction amount data of the elastic members 503 in each area, in order to redistribute the biomass boiler flue gas flow rate and ensure that the biomass boiler flue gas can reach a uniform distribution state when passing through the detection mechanism 5 and entering the catalyst module 104, such as Figures 11 to 13The SCR denitrification device shown has a second operating state, a third operating state and a fourth operating state.

[0037] The specific process of adjusting the deflection angle of the guide plate 302 is as follows: the control system accurately identifies the area where the movable plate 502 is subjected to the greatest impact and the area where the movable plate 502 is subjected to the least impact based on the distribution of the expansion and contraction amount of the elastic member 503 on the detection frame 501. According to the difference in the expansion and contraction amount of the elastic member 503 between the two areas, the guide plate 302 corresponding to the area of ​​the movable plate 502 subjected to the greatest impact is precisely driven and controlled by the deflection mechanism 4, so that it is deflected toward the area where the movable plate 502 subjected to the least impact is located. This deflection operation causes the biomass boiler flue gas flowing through the detection mechanism 5 and about to enter the catalyst module 104 to redirect part of the flow from the area of ​​the movable plate 502 subjected to the greatest impact to the area of ​​the movable plate 502 subjected to the least impact under the influence of the guide plate 302, thereby achieving the ultimate goal of uniform distribution of the biomass boiler flue gas inside the catalyst module 104.

[0038] The present invention sets a guide plate 302 and an elastic member 503. The control system monitors the change in the expansion and contraction amount of the elastic member 503 inside the slot of the mounting frame to determine the distribution of the biomass boiler flue gas when it passes through the detection mechanism 5 and enters the catalyst module 104. When the control system detects that the biomass boiler flue gas is unevenly distributed, it will dynamically adjust the deflection angle of the corresponding guide plate 302 according to the expansion and contraction amount data of the elastic member 503 in each area, aiming to redistribute the biomass boiler flue gas flow rate and ensure that it can reach a uniform distribution state when it passes through the detection mechanism 5 and enters the catalyst module 104.

[0039] Example 2: The SCR denitration device of Example 1 can divert the biomass boiler flue gas, but in the process of catalytic conversion between the catalyst and the biomass boiler flue gas, as the flow rate of the biomass boiler flue gas increases, the erosion effect of the biomass boiler flue gas on the catalyst will increase simultaneously. When the bottom of the catalyst is severely eroded, it may cause the collapse of the catalyst layer, so that it is necessary to take measures to stop production and replace it; at the same time, with the continuous operation of the denitration system, fly ash particles gradually deposit on the surface of the catalyst, forming a pore blockage phenomenon, thereby reducing the effective channel area for the airflow to pass through and reducing the catalytic reduction effect of the catalyst. In view of this, based on the structure of the SCR denitration device of Example 1, such as Figure 3~4 As shown, a partition plate 2 is vertically arranged in the center of the reactor body 101, and the partition plate 2 divides the reactor body 101 into two equal areas; the guide mechanism 3, the detection mechanism 5 and the catalyst module 104 arranged in the reactor body 101 are distributed in a mirror image with the partition plate 2 as the center line.

[0040] like Figure 4As shown, the partition plate 2 is provided with a first through hole 201 and a second through hole 202 distributed in an array; a control valve is provided inside the first through hole 201, and the first through hole 201 is correspondingly arranged between the flow guide mechanism 3 and the detection mechanism 5; a control valve is provided inside the second through hole 202, and the second through hole 202 is correspondingly arranged between the catalyst module 104 and the flow guide mechanism 3.

[0041] like Fig.10 As shown, the partition plate 2 divides the reactor body 101 into an X region and a Y region along the middle. In the initial state, the control valves in the first through hole 201 and the second through hole 202 are both in a closed state, that is, the X region and the Y region cannot communicate with each other through the first through hole 201 and the second through hole 202.

[0042] When in use, after the biomass boiler flue gas enters the reactor body 101 through the air inlet end 102, it is affected by the partition plate 2 and is divided into two biomass boiler flue gases at the top of the partition plate 2. The two biomass boiler flue gases enter the X region and the Y region respectively. The biomass boiler flue gases entering the respective regions react with the catalyst modules 104 in the respective regions respectively. As the biomass boiler flue gas flows, the biomass boiler flue gases entering the X region and the Y region merge at the air outlet end 103 and are finally discharged from the reactor body 101. The specific situation is as follows: Fig.10 shown.

[0043] When the flue gas from the biomass boiler flows in the X region and the Y region, the control system detects whether the catalyst module 104 is over-eroded or blocked through the detection mechanisms 5 distributed on the upper and lower sides of the single catalyst module 104 .

[0044] In this embodiment, the reactor body 101 is provided with three sections, namely, the S1 section, the S2 section and the S3 section, and the catalyst module 104 is provided at the junction of the S1 section and the S2 section and at the junction of the S2 section and the S3 section. It should be noted that: under normal circumstances, the difference in the expansion and contraction amount of the elastic member 503 between the sections in the same area is in a stable state.

[0045] like Fig.11As shown, when the control system detects that the difference in the amount of expansion and contraction of some elastic members 503 between the S1 interval and the S2 interval in the X region exceeds the stable state, it indicates that the catalyst module 104 set between the S1 interval and the S2 interval in the X region has a regional blockage phenomenon, causing the expansion and contraction of some elastic members 503 in the S1 interval to be much greater than the expansion and contraction of the corresponding elastic members 503 in the S2 interval, that is, the difference in the amount of expansion and contraction of some elastic members 503 between the S1 interval and the S2 interval exceeds the stable state. When the control system detects that the catalyst module 104 has a regional blockage phenomenon, the control system controls the guide plate 302 in the S1 interval of the Y region to deflect. After the guide plate 302 deflects, the distance between the guide plates 302 is reduced, thereby reducing the biomass boiler flue gas flow entering the S1 interval of the Y region, that is, increasing the biomass boiler flue gas flow entering the S1 interval of the X region. While controlling the deflection of the guide plate 302 in the S1 section of the Y region, the guide plate 302 in the S1 section of the X region is reciprocatingly deflected. This reciprocating deflection mechanism causes the flue gas of the biomass boiler entering the S1 section of the X region to impact the movable plate 502 in a pulse form, thereby driving the movable plate 502 to reciprocate up and down on the detection frame 501. As the movable plate 502 moves up and down, the movable plate 502 will knock on the top of the catalyst module 104 located at the junction of the S1 and S2 sections in the X region. This knocking process is intended to effectively clean the blocked area on the catalyst module 104, thereby preventing the occurrence of a decrease in the catalytic reduction effect of the catalyst due to blockage.

[0046] like Fig.12 As shown, when the control system monitors that the difference in the expansion and contraction amount of all elastic members 503 between the S1 interval and the S2 interval in the X region exceeds the stable state, that is, the expansion and contraction amount of the elastic member 503 in the S1 interval is significantly greater than the expansion and contraction amount of the corresponding elastic member 503 in the S2 interval, this indicates that the catalyst module 104 located between the S1 interval and the S2 interval in the X region has been blocked, and this blockage causes the biomass boiler flue gas to be unable to smoothly move downward through the catalyst module 104, thereby causing the difference in the expansion and contraction amount of the elastic member 503 between the S1 and S2 intervals to exceed the normal range. When the control system detects that the catalyst module 104 has been blocked, it immediately controls the guide plates 302 in the S1 interval and the S2 interval in the X region to deflect to block the flow path of the biomass boiler flue gas. The specific situation is as follows Fig.12 At the same time, the guide plate 302 located in the interval S2 of the Y region is controlled to deflect. After the guide plate 302 is deflected, the distance between the guide plates 302 is shortened, thereby reducing the biomass boiler flue gas flow entering the interior of the interval S2 of the Y region. The specific situation is as follows Fig.12 shown.

[0047] After the deflection operation of the guide plate 302 in the X region and the Y region is completed, the catalyst module 104 between the S1 section and the S2 section of the X region is effectively isolated (the area where the catalyst module 104 is located is set as the isolation area). Subsequently, the control system opens the control valve in the second through hole 202 disposed below the catalyst module 104 between the S1 section and the S2 section, and the control valve in the first through hole 201 inside the S2 section, so that the flue gas of the biomass boiler can enter the isolation area through the second through hole 202, and enter the X region from the Y region through the first through hole 201. After the adjustment of the first through hole 201 and the second through hole 202, when the biomass boiler flue gas enters the reactor body 101 through the air inlet end 102, the biomass boiler flue gas cannot directly enter the interior of the X region, but first enters the Y region, and as the biomass boiler flue gas continues to flow, when the biomass boiler flue gas enters the interior of the S2 region, it is affected by the guide plate 302 inside the S2 region, and the biomass boiler flue gas is diverted above the guide plate 302, and a part of the biomass boiler flue gas enters the isolation region through the second through hole 202, and the other part enters below the guide plate 302. It should be noted that: by controlling the deflection angle of the guide plate 302, the biomass boiler flue gas flow entering the isolation region can be greater than the biomass boiler flue gas flow entering below the guide plate 302.

[0048] The biomass boiler flue gas entering the isolation area impacts the area below the catalyst module 104 between the S1 interval and the S2 interval, and recoils and cleans the fly ash blocked inside the catalyst module 104 until the control system detects a significant change in the expansion and contraction amount of the elastic part 503 above the catalyst module 104, indicating that the biomass boiler flue gas has completed the recoil and cleaning process of the catalyst module 104.

[0049] During this process, the biomass boiler flue gas entering the guide plate 302 below the S2 interval of the Y region is split again at the corresponding first through hole 201. Part of the biomass boiler flue gas enters the S3 interval of the Y region after being catalyzed by the catalyst module 104, and the other part enters the S2 interval of the X region through the first through hole 201, thereby avoiding the biomass boiler flue gas from staying in a single area for a long time, thereby reducing the catalyst module 104 in the area due to the excessive flow of the biomass boiler flue gas entering, resulting in excessive erosion of the catalyst module 104. When the adjustment is completed, all electrical components inside the reactor body 101 are restored to the initial state.

[0050] like Fig.13As shown, when the control system monitors that the difference in the expansion and contraction amount of all elastic members 503 between the S1 interval and the S2 interval in the X region is lower than the stable state threshold, that is, the expansion and contraction amount of the elastic member 503 in the S1 interval is basically consistent with the expansion and contraction amount of the corresponding elastic member 503 in the S2 interval or the change range is extremely small, this phenomenon reveals that the catalyst module 104 located between the S1 and S2 intervals in the X region may have suffered excessive erosion. Since the biomass boiler flue gas fails to obtain an effective catalytic reaction and sufficient kinetic energy consumption when passing through the catalyst module 104, the difference in the expansion and contraction amount of the elastic member 503 between the S1 and S2 intervals is maintained at a level lower than the normal stable state.

[0051] When the control system detects excessive erosion of the catalyst module 104, the guide plates 302 in the S1 and S2 regions of the X region are controlled to deflect to block the original flow path of the flue gas from the biomass boiler. For specific deflection conditions, please refer to Fig.13 As shown. After the deflection operation of the guide plate 302 is completed, the catalyst module 104 between the S1 section and the S2 section of the X region is effectively isolated to form an independent isolation area. In this isolation area, the catalyst module 104 no longer participates in the catalytic reduction reaction, which is intended to prevent the biomass boiler flue gas from failing to effectively react when passing through the catalyst module 104 and affecting the overall reaction effect of other biomass boiler flue gases. It should be noted that after the reactor body 101 completes the catalytic reduction reaction of the biomass boiler flue gas, the staff needs to replace the catalyst module 104 in the isolation area in a timely manner to ensure the subsequent efficient operation of the system.

[0052] After the catalyst module 104 between the S1 section and the S2 section of the X region is isolated, the control system will start the control valve in the first through hole 201 set inside the S2 section, so that the biomass boiler flue gas can smoothly pass through this channel from the Y region to the X region. This series of operations is intended to optimize the flow path of the biomass boiler flue gas and improve the efficiency and stability of the catalytic reduction reaction. After adjusting the first through hole 201, when the biomass boiler flue gas enters the reactor body 101 from the air inlet end 102, since the catalyst module 104 between the S1 section and the S2 section of the X region has been effectively isolated, the biomass boiler flue gas cannot directly flow into the X region, but is first directed to the Y region; with the continuous flow of the biomass boiler flue gas, in the S2 section of the Y region, the biomass boiler flue gas is diverted below the guide plate 302: a part of the biomass boiler flue gas enters the S3 section of the Y region after being catalytically treated by the catalyst module 104; the other part smoothly enters the S2 section of the X region through the first through hole 201. This diversion mechanism is intended to prevent the biomass boiler flue gas from being retained in any one area for a long time, thereby effectively alleviating the problem of excessive erosion of the catalyst module 104 in that area.

[0053] After the biomass boiler flue gas of the present invention enters the reactor body 101 through the air inlet end 102, it is divided into two streams by the partition plate 2 and enters the X area and the Y area respectively, and reacts with the catalyst module 104 in each area; then, the two streams of biomass boiler flue gas merge and are discharged at the air outlet end 103; during the flow of the biomass boiler flue gas, the control system monitors the expansion and contraction amount of the elastic member 503 on the upper and lower sides of the catalyst module 104 through the detection mechanism 5 to determine whether the catalyst module 104 is blocked or over-eroded. When the catalyst module 104 in a certain interval in the X area is blocked, the control system controls the deflection of the guide plate 302 in the corresponding interval of the Y area to reduce the flow rate of the biomass boiler flue gas entering the interval, and at the same time controls the reciprocating deflection of the guide plate 302 in the corresponding interval of the X area to impact the movable plate 502 in a pulse manner to clear the blocked catalyst module 104. If a certain section of the catalyst module 104 in the X area is seriously blocked, the control system will control the deflection of the relevant guide plate 302 to block the biomass boiler flue gas flow path, and open other channels to allow the biomass boiler flue gas to recoil and clean the blocked area. When excessive erosion of the catalyst module 104 is detected, the control system will also control the deflection of the relevant guide plate 302 to isolate the damaged module to prevent it from affecting the overall catalytic effect. After completing the deflection operation of the guide plate 302, the control system adjusts the biomass boiler flue gas flow path, optimizes the biomass boiler flue gas distribution by opening or closing specific channels, and ensures the efficient operation of the catalyst modules 104 in each area.

[0054] It should be noted that, in this embodiment, only the control method for the blockage or erosion of the catalyst module 104 between the S1 section and the S2 section of the X region is explained. If there is a problem with other catalyst modules 104 in the X region or the Y region of the SCR denitration device, the above method can also be used to clean up the blockage or isolate the catalyst module 104 to prevent excessive erosion.

[0055] Example 3: Based on the structure of the SCR denitration device of Example 1 and Example 2, Figure 1 As shown, an ammonia spraying grid 400 is radially arranged in the flue gas guide duct 200, and the ammonia spraying grid 400 is connected to an ammonia spraying assembly 500 arranged outside the flue gas guide duct 200. The ammonia spraying assembly 500 sprays ammonia into the flue gas guide duct 200 through the ammonia spraying grid 400. The ammonia is evenly sprayed into the flue gas upstream of the reactor body 101 through the ammonia spraying grid 400. The ammonia spraying grid 400 ensures that the ammonia is evenly distributed, thereby improving the denitrification efficiency of the SCR denitrification device and reducing the ammonia escape rate.

[0056] like Figure 1As shown, the ammonia spraying assembly 500 includes a fan 5001, a heater 5002, an evaporator 5003 and a gas mixer 5004. The fan 5001 has an air inlet and an air outlet, which are used to dilute the ammonia gas sprayed into the flue gas guide duct 200. The heater 5002 is connected to the air outlet of the fan 5001, and the heater 5002 heats the air mixed with the ammonia gas to increase the molecular motion speed of the ammonia gas. The evaporator 5003 is connected to the external liquid ammonia tank, and the evaporator 5003 is used to heat the liquid ammonia to evaporate it. A flow controller is provided between the liquid pump and the evaporator 5003, and the flow controller is used to control the flow rate of liquid ammonia passed into the evaporator 5003 by the liquid pump. One end of the gas mixer 5004 is connected to the evaporator 5003, and the other end is connected to the ammonia injection grid 400. The gas mixer 5004 is used to mix the heated air and ammonia, wherein the dilution air is provided by the fan 5001 to ensure that the ammonia reaches an appropriate concentration and dispersion before being sprayed into the flue gas.

[0057] like Figure 1 As shown, a plurality of groups of ammonia spray grids 400 are distributed in an array along the flue gas guide duct 200, and a height difference is set between two adjacent ammonia spray grids 400. By setting the position of the ammonia spray grids 400, the ammonia sprayed from the ammonia spray grids 400 has different speeds at the same position, thereby improving the mixing degree of ammonia and flue gas.

[0058] like Figure 1 As shown, a static mixer 300 is provided on one side of the ammonia injection grid 400 close to the SCR denitrification device 1. The static mixer 300 has a plurality of vanes distributed in an array, and the vanes are used to increase gas disturbance and accelerate the mixing of ammonia and biomass boiler flue gas.

[0059] During operation, liquid ammonia is first evaporated and gasified through the evaporator 5003 before being injected into the SCR denitration device 1. The evaporator 5003 adopts an electric heating method to ensure that the ammonia can be fully gasified. The gasified ammonia is evenly mixed with the dilution air in the gas mixer 5004 to ensure uniform distribution when it is subsequently sprayed into the biomass boiler flue gas. The evenly mixed ammonia is sprayed into the biomass boiler flue gas upstream of the SCR reactor through the ammonia spray grid 400. The ammonia spray grid 400 ensures that the ammonia can be evenly dispersed in the biomass boiler flue gas. When the ammonia is dispersed in the biomass boiler flue gas, the ammonia is fully in contact with the nitrogen oxides in the biomass boiler flue gas, preparing for the subsequent catalytic reduction reaction. After the biomass boiler flue gas enters the reactor body 101 through the air inlet end 102, it contacts the catalyst module 104 inside it. Under the action of the catalyst, the ammonia reacts with the nitrogen oxides in the biomass boiler flue gas to generate harmless nitrogen and water. Through the above catalytic reduction reaction, nitrogen oxides in the flue gas of the biomass boiler are effectively removed, thereby completing the SCR denitrification process. It should be noted that the operation path of the flue gas of the biomass boiler is as follows: the flue gas of the biomass boiler enters the flue gas guide duct 200 from the economizer 100, and is mixed with ammonia through the static mixer 300 in the middle of the flue gas guide duct 200, and then enters the reactor body 101 through the air inlet end 102 and reacts with the catalyst module 104 inside it.

[0060] The SCR denitration catalyst of the present invention adopts a rare earth coupled modified catalyst having resistance to alkali metal poisoning, thereby improving the resistance to alkali metal poisoning of the SCR denitration catalyst and improving the service life and working efficiency of the SCR denitration catalyst.

[0061] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. An SCR denitrification system for biomass boiler flue gas, characterized in that: The SCR denitration system comprises: An SCR denitration device (1), the SCR denitration device (1) comprising a reactor body (101) having an air inlet end (102) and an air outlet end (103), wherein a plurality of groups of catalyst modules (104) are arranged in layers along a height direction of the reactor body (101); A flue gas guide pipe (200), one end of the flue gas guide pipe (200) being connected to the economizer (100), and the other end of the flue gas guide pipe (200) being connected to the air inlet end (102) of the reactor body (101); the flue gas of the biomass boiler enters the reactor body (101) from the economizer (100) via the flue gas guide pipe (200) and reacts with the multi-layer catalyst module (104); A flow guiding mechanism (3), the flow guiding mechanism (3) comprising a plurality of groups arranged along the height direction of the reactor body, each group of the flow guiding mechanism (3) being located above its corresponding catalyst module (104) and being used to guide and regulate the flow direction and flow rate of the biomass boiler flue gas; A detection mechanism (5), the detection mechanism (5) comprising a plurality of groups arranged along the height direction of the reactor body, each group of the detection mechanism (5) being located between its corresponding catalyst module (104) and the flow guiding mechanism (3), the detection mechanism (5) being used to monitor the flow velocity and distribution of the biomass boiler flue gas flowing through the catalyst module (104).

2. The SCR denitrification system for biomass boiler flue gas according to claim 1, characterized in that: The flow guiding mechanism (3) comprises: A flow guide frame (301), wherein the flow guide frame (301) is horizontally arranged in the reactor body (101); A guide plate (302), the guide plate (302) comprising a plurality of groups arranged in a parallel array along the inside of a guide frame (301), the guide plate (302) comprising a guide shaft (303) and guide wing plates (304) symmetrically distributed along both sides of the guide shaft (303); a deflection mechanism (4) is provided at the connection between the two ends of the guide shaft (303) and the guide frame (301), the deflection mechanism (4) being used to drive the guide plate (302) to reciprocate along the guide frame (301) to control the flow path of the flue gas of the biomass boiler.

3. The SCR denitrification system for biomass boiler flue gas according to claim 2, characterized in that: The deflection mechanism (4) comprises mounting grooves (404) correspondingly arranged at both ends of the guide shaft body (303), and an arc-shaped groove (405) is provided on the inner wall of the mounting groove (404) in the circumferential direction; Pushing members (401) are correspondingly arranged on the two side walls of the guide frame, an inner end of the pushing member (401) is provided with a mounting shaft (402), the mounting shaft (402) is correspondingly clamped in the mounting groove (404), and a limiting protrusion (403) slidably connected to the arc groove (405) is provided on the side wall of the mounting shaft (402); The pushing member (401) drives the installation shaft (402) to rotate, and the limiting protrusion (403) squeezes the arc groove (405) to drive the guide plate (302) to deflect and adjust the guide angle.

4. The SCR denitrification system for biomass boiler flue gas according to any one of claims 1 to 3, characterized in that: The detection mechanism (5) comprises: A detection frame (501), the detection frame (501) being horizontally arranged in the reactor body (101), and having mounting frame slots distributed in an array; A movable plate (502), the movable plate (502) comprising a plurality of plates correspondingly arranged in the slot holes (504) of the mounting frame; the movable plate (502) is connected to the inner side wall of the slot holes (504) of the mounting frame via a plurality of elastic members (503) arranged around the movable plate (502); when the flue gas of the biomass boiler impacts the movable plate (502), the expansion and contraction amount of the elastic members (503) reflects the impact strength of the flue gas of the biomass boiler on the movable plate (502).

5. The SCR denitrification system for biomass boiler flue gas according to claim 4, characterized in that: A partition plate (2) is vertically arranged in the center of the reactor body (101), and the partition plate (2) divides the reactor body (101) into two equal areas; The flow guiding mechanism (3), the detection mechanism (5) and the catalyst module (104) arranged in the reactor body (101) are distributed in a mirror image with the partition plate (2) as the center line.

6. The SCR denitrification system for biomass boiler flue gas according to claim 5, characterized in that: The partition plate (2) is provided with first through holes (201) and second through holes (202) distributed in an array; A control valve is provided inside the first through hole (201), and the first through hole (201) is correspondingly arranged between the flow guiding mechanism (3) and the detection mechanism (5); A control valve is arranged inside the second through hole (202), and the second through hole (202) is correspondingly arranged between the catalyst module (104) and the flow guide mechanism (3).

7. The SCR denitrification system for biomass boiler flue gas according to claim 4, characterized in that: An ammonia spraying grid (400) is arranged radially in the flue gas guide duct (200); the ammonia spraying grid (400) is connected to an ammonia spraying assembly (500) arranged outside the flue gas guide duct (200); and the ammonia spraying assembly (500) sprays ammonia into the flue gas guide duct (200) through the ammonia spraying grid (400).

8. The SCR denitrification system for biomass boiler flue gas according to claim 7, characterized in that: The ammonia spraying assembly (500) comprises a fan (5001), a heater (5002), an evaporator (5003) and a gas mixer (5004); the fan (5001) has an air inlet and an air outlet, and is used to dilute the ammonia sprayed into the flue gas guide duct (200); the heater (5002) is connected to the air outlet of the fan (5001), and the heater (5002) heats the air mixed with the ammonia; the evaporator (5003) is connected to an external liquid ammonia tank, and the evaporator (5003) is used to heat the liquid ammonia to evaporate it; one end of the gas mixer (5004) is connected to the evaporator (5003), and the other end is connected to the ammonia spraying grid (400), and the gas mixer (5004) is used to mix the heated air and the ammonia.

9. The SCR denitrification system for biomass boiler flue gas according to claim 8, characterized in that: The ammonia injection grids (400) are arranged in a plurality of groups in an array along the flue gas guide duct (200), and a height difference is provided between two adjacent ammonia injection grids (400).

10. The SCR denitrification system for biomass boiler flue gas according to claim 9, characterized in that: A static mixer (300) is provided on one side of the ammonia injection grid (400) close to the SCR denitration device (1), wherein a plurality of vanes are arranged in an array in the static mixer (300), and the vanes are used to increase gas disturbance and accelerate mixing of ammonia and biomass boiler flue gas.

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