Coal-fired power plant flue gas denitration device based on SCR (Selective Catalytic Reduction) technology

Abstract

The utility model provides a coal-fired power plant flue gas denitration device based on SCR (Selective Catalytic Reduction) technology, which relates to the field of coal-fired power plant flue gas denitration and comprises a selective catalytic reduction reactor, a flue gas inlet is arranged at the upper end of the selective catalytic reduction reactor, an ammonia-air mixer is connected to the outer wall of the selective catalytic reduction reactor, and the ammonia-air mixer is connected with a flue gas outlet of the selective catalytic reduction reactor. The device comprises a selective catalytic reduction reactor, a purified smoke outlet is formed in the outer wall, close to the bottom, of the selective catalytic reduction reactor, a premixing assembly is arranged in the selective catalytic reduction reactor, an air uniformizing assembly is arranged on the lower side of the premixing assembly, a catalysis assembly is arranged on the lower side of the air uniformizing assembly, and the air uniformizing assembly comprises an upper net plate and a lower net plate. A horizontal curved plate is arranged between the upper screen plate and the lower screen plate, the catalysis assembly comprises a drawing frame, and a grid frame is arranged in the drawing frame. The flue gas denitration device solves the problems that an existing flue gas denitration device is provided with a uniform mixing structure, the denitration effect is poor, and a catalyst module is inconvenient to replace.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas denitration in coal-fired power plants, and in particular to a flue gas denitration device in coal-fired power plants based on the SCR technology. Background Art

[0002] In the selective catalytic reduction flue gas desulfurization device (SCR) of a coal-fired power plant, ammonia consumption is one of the most important performance evaluation indicators of the flue gas denitrification device. In the "Performance Acceptance Test Specification for Flue Gas Denitrification Devices in Coal-fired Power Plants" (DL / T 260-2012), this indicator is a performance indicator that should be done. After searching, the prior art (publication number: CN113694716B) records "a calibration method and system for an ammonia mass flowmeter for a flue gas denitrification device. The purpose of the present invention is to overcome the problem that the ammonia mass flowmeter of the denitrification system cannot be calibrated, and a calibration method and system for an ammonia mass flowmeter for a flue gas denitrification device are provided, which can simply and accurately calibrate the ammonia mass flowmeter of the flue gas denitrification device, and its calibration meets the calibration requirements of JJG 1038 2008. The calibration method and system provided by the present invention are simple, do not require special calibration devices, and can be calibrated using conventional equipment and instruments in thermal power plants. The calibration results are reliable and meet the requirements of JJG 1038 2008, providing a guarantee for the normal operation of the denitrification system."

[0003] Although the calibration method and system of the ammonia mass flowmeter for the flue gas denitrification device in the prior art have achieved the metering and detection effect of flue gas denitrification, there are still some shortcomings: the SCR reactor involved in the existing flue gas denitrification device lacks a uniform distribution structure for ammonia, air and flue gas, resulting in uneven mixing and poor denitrification effect. At the same time, the catalyst module used in conjunction has the defect of being inconvenient to replace at a later stage. Utility Model Content

[0004] In order to overcome the defects of the prior art, a flue gas denitrification device for a coal-fired power plant based on SCR technology is provided to solve the problem that the existing flue gas denitrification device has a uniform mixing structure, resulting in deviation in the denitrification effect and inconvenience in replacing the catalyst module.

[0005] To achieve the above-mentioned purpose, a flue gas denitrification device for a coal-fired power plant based on SCR technology is provided, comprising: a selective catalytic reduction reactor, a flue gas inlet is provided at the upper end of the selective catalytic reduction reactor, and an ammonia-air mixer is connected to the outer wall of the selective catalytic reduction reactor, and a clean smoke outlet is provided on the outer wall of the selective catalytic reduction reactor near the bottom, a premixing component is provided inside the selective catalytic reduction reactor, and an air distribution component is provided on the lower side of the premixing component, and a catalytic component is provided on the lower side of the air distribution component, the air distribution component comprises an upper mesh plate and a lower mesh plate, and a horizontal curved plate is provided between the upper mesh plate and the lower mesh plate, the catalytic component comprises a pull-out frame, and a grid frame is provided inside the pull-out frame, and catalyst fillers are provided in the grids of the grid frame.

[0006] Furthermore, the pipe connected to the inner side end of the ammonia-air mixer is inserted into the pipe at the lower end of the flue gas inlet, and the pipe at the lower end of the flue gas inlet is connected to the upper end of the premixing assembly.

[0007] Furthermore, the premixing assembly includes a conical structured flow guide cover, and the flow guide cover is a structure that is narrow at the top and wide at the bottom, and inclined curved plates are provided inside the flow guide cover, and flow guide gaps are provided between the inclined curved plates.

[0008] Furthermore, the air distribution component includes a fixing plate, and the fixing plate is fixed to the inner wall of the selective catalytic reduction reactor, and the fixing plate is connected around the upper mesh plate and the lower mesh plate.

[0009] Furthermore, the horizontal curved plate is configured as a multi-layer structure which is arranged at equal intervals up and down, and vertically penetrating ventilation holes are provided inside the horizontal curved plate.

[0010] Furthermore, the catalytic assembly is provided with a plurality of groups which are layered with equal spacing up and down, and the drawer frame is slidably inserted into the inner side of the guide rail provided on the inner wall of the selective catalytic reduction reactor.

[0011] Furthermore, a plurality of placement grooves of equal-sized rectangular structures are provided on the inner side of the grid frame, a grid bottom plate is provided at the bottom of the placement grooves, and the catalyst fillers are all placed in the placement grooves, and a handle is provided on the front side of the pull-out frame.

[0012] The beneficial effects of the utility model are:

[0013] 1. When in use, the original flue gas enters the selective catalytic reduction reactor through the flue gas inlet, and the ammonia (reducing agent) and air are mixed in the ammonia-air mixer and enter the selective catalytic reduction reactor. The two are pre-mixed in the pre-mixing component through the guide cover, inclined curved plate and guide gap included in the pre-mixing component. At this time, the reduction reaction with the original flue gas begins, and then the mixed gas is dispersed by turbulence through the lower air distribution component, the upper mesh plate, the horizontal curved plate, the ventilation hole and the lower mesh plate included in the air distribution component, and diffused downward evenly under the cross-sectional area of ​​the reactor, thereby achieving a large area and uniform contact with the lower catalytic component, and achieving a good catalytic denitrification reaction;

[0014] 2. The pull-out frame can be pulled out by the guide rail through the handle, and then the catalyst module can be placed independently through the multiple placement slots set inside the grid frame. It is also convenient to take it out independently, so that a single catalyst module can be replaced, and the overall catalyst module can be replaced, which is more convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a front view structural schematic diagram of an embodiment of the utility model.

[0016] Figure 2 This is a schematic diagram of the cross-sectional structure of a premixing component according to an embodiment of the present utility model.

[0017] Figure 3 It is a schematic diagram of the cross-sectional structure of the wind equalizing component of an embodiment of the utility model.

[0018] Figure 4 It is a schematic diagram of the top view of the catalytic component of an embodiment of the utility model.

[0019] In the figure: 1. Selective catalytic reduction reactor; 11. Flue gas inlet; 12. Clean smoke outlet; 13. Ammonia-air mixer; 2. Premixing assembly; 21. Air deflector; 22. Inclined curved plate; 23. Air deflection gap; 3. Air distribution assembly; 31. Fixed plate; 32. Upper mesh plate; 33. Horizontal curved plate; 34. Ventilation hole; 35. Lower mesh plate; 4. Catalytic assembly; 41. Pull-out frame; 42. Grid bottom plate; 43. Placement slot; 44. Grid rack; 45. Handle. DETAILED DESCRIPTION

[0020] Reference Figures 1 to 4As shown, the utility model provides a flue gas denitrification device for a coal-fired power plant based on SCR technology, comprising: a selective catalytic reduction reactor 1, a flue gas inlet 11 is provided at the upper end of the selective catalytic reduction reactor 1, and an ammonia-air mixer 13 is connected to the outer wall of the selective catalytic reduction reactor 1, and a clean smoke outlet 12 is provided on the outer wall near the bottom of the selective catalytic reduction reactor 1, a premixing component 2 is provided inside the selective catalytic reduction reactor 1, and an air distribution component 3 is provided at the lower side of the premixing component 2, and a catalytic component 4 is provided at the lower side of the air distribution component 3, the air distribution component 3 comprises an upper mesh plate 32 and a lower mesh plate 35, and a horizontal curved plate 33 is provided between the upper mesh plate 32 and the lower mesh plate 35, the catalytic component 4 comprises a pull-out frame 41, and a grid frame 44 is provided inside the pull-out frame 41, and catalyst fillers are provided in the grids of the grid frame 44.

[0021] In this embodiment, the selective catalytic reduction reactor 1 is a flue gas deoxidation reactor under the SCR technology, and the reactor also includes an internal premixing component 2, an air distribution component 3 and a catalytic component 4.

[0022] The ammonia-air mixer 13 involved adopts the ammonia-air mixing device mentioned in the prior art (disclosed as CN214915031U) to achieve full and uniform mixing of ammonia (reducing agent) and air.

[0023] like Figure 1 and Figure 2 As shown, the pipe connected to the inner end of the ammonia-air mixer 13 is inserted into the pipe at the lower end of the flue gas inlet 11, and the pipe at the lower end of the flue gas inlet 11 is connected to the upper end of the premixing component 2. The premixing component 2 includes a guide cover 21 with a conical structure, and the guide cover 21 is a structure that is narrow at the top and wide at the bottom, and an inclined curved plate 22 is provided inside the guide cover 21, and a guide gap 23 is provided between the inclined curved plates 22.

[0024] As a preferred embodiment, by providing a premixing assembly 2, ammonia, air and flue gas are premixed in the pipeline, and then the guiding effect of the inclined curved plate 22 is used to achieve uniform diffusion of the mixed gas downward over a large area.

[0025] like Figure 1 and Figure 3 As shown, the air equalizing component 3 includes a fixed plate 31, and the fixed plate 31 is fixed to the inner wall of the selective catalytic reduction reactor 1, and the fixed plate 31 is connected around the upper mesh plate 32 and the lower mesh plate 35. The horizontal curved plate 33 is set to a multi-layer structure arranged at equal intervals up and down, and the horizontal curved plate 33 is provided with vertically penetrating ventilation holes 34 inside.

[0026] As a preferred embodiment, the upper mesh plate 32, the lower mesh plate 35 and the ventilation holes 34 are provided to achieve the effect of upper and lower ventilation, and then the horizontal curved plate 33 is used to facilitate the realization of low gas flow resistance, so that the effect of lateral diffusion is achieved in each layer, thereby achieving the effect of uniform downward flow.

[0027] like Figure 1 and Figure 4 As shown, the catalytic assembly 4 is provided with a plurality of groups of layers with equal spacing up and down, and a pull-out frame 41 is slidably inserted into the inner side of a guide rail provided on the inner wall of the selective catalytic reduction reactor 1, a plurality of placement grooves 43 of equal-sized rectangular structures are provided on the inner side of a grid frame 44, a grid bottom plate 42 is provided at the bottom of the placement groove 43, and the catalyst fillers are all placed in the placement groove 43, and a handle 45 is provided on the front side of the pull-out frame 41.

[0028] Specifically, the upper side of the drawer frame 41 is configured as an open structure, and the grid base plate 42 at the bottom is configured as an integral structure, while the catalyst filler is configured as a modular structure, so as to facilitate overall removal and placement.

[0029] During use, the original flue gas enters the selective catalytic reduction reactor through the flue gas inlet, and at the same time, ammonia (reducing agent) and air are mixed through the ammonia-air mixer and then enter the selective catalytic reduction reactor, and the two are pre-mixed in the premixing component through the guide cover, inclined curved plate and guide gap included in the premixing component. At this time, the reduction reaction with the original flue gas also begins, and then through the lower side of the wind equalizing component, through the upper mesh plate, horizontal curved plate, ventilation holes and lower mesh plate included in the wind equalizing component, the mixed gas is turbulently dispersed and diffused downward evenly under the cross-sectional area of ​​the reactor, thereby achieving large-area and uniform contact with the lower catalyst component, achieving a good catalytic deoxidation reaction, and using the guide rail to pull out the pull-out frame through the handle, so that the catalyst module can be placed and removed independently.

[0030] The SCR technology-based flue gas denitrification device for coal-fired power plants of the utility model can effectively solve the problems of the existing flue gas denitrification devices having a uniform mixing structure, resulting in deviation in the denitrification effect and inconvenience in replacing the catalyst module. It achieves the effects of pre-mixing, uniform mixing and uniform diffusion on the basis of the existing SCR technology-based flue gas denitrification device for coal-fired power plants, thereby enhancing the flue gas denitrification effect and facilitating the replacement of the catalytic module.

Claims

1. A flue gas denitrification device for a coal-fired power plant based on SCR technology, comprising: A selective catalytic reduction reactor (1), characterized in that: a flue gas inlet (11) is provided at the upper end of the selective catalytic reduction reactor (1), an ammonia-air mixer (13) is connected to the outer wall of the selective catalytic reduction reactor (1), and a clean smoke outlet (12) is provided on the outer wall of the selective catalytic reduction reactor (1) near the bottom; a premixing assembly (2) is provided inside the selective catalytic reduction reactor (1), and an air distribution assembly (3) is provided at the lower side of the premixing assembly (2), and a catalytic assembly (4) is provided at the lower side of the air distribution assembly (3), the air distribution assembly (3) comprises an upper mesh plate (32) and a lower mesh plate (35), and a horizontal curved plate (33) is provided between the upper mesh plate (32) and the lower mesh plate (35), the catalytic assembly (4) comprises a drawer frame (41), and a grid frame (44) is provided inside the drawer frame (41), and catalyst fillers are provided in the grids of the grid frame (44).

2. The SCR technology-based flue gas denitrification device for coal-fired power plants according to claim 1, characterized in that: The pipe connected to the inner end of the ammonia-air mixer (13) is inserted into the pipe at the lower end of the flue gas inlet (11), and the pipe at the lower end of the flue gas inlet (11) is connected to the upper end of the premixing assembly (2).

3. The SCR technology-based flue gas denitrification device for coal-fired power plants according to claim 1, characterized in that: The premixing assembly (2) comprises a conical flow guide cover (21), wherein the flow guide cover (21) is narrow at the top and wide at the bottom, and an inclined curved plate (22) is provided inside the flow guide cover (21), and flow guide gaps (23) are provided between the inclined curved plates (22).

4. The SCR technology-based flue gas denitrification device for coal-fired power plants according to claim 1, characterized in that: The air distribution component (3) comprises a fixing plate (31), wherein the fixing plate (31) is fixed to the inner wall of the selective catalytic reduction reactor (1), and the fixing plate (31) is connected around the upper mesh plate (32) and the lower mesh plate (35).

5. The SCR technology-based flue gas denitrification device for coal-fired power plants according to claim 1, characterized in that: The horizontal curved plate (33) is configured as a multi-layer structure arranged at equal intervals up and down, and a vertically penetrating ventilation hole (34) is provided inside the horizontal curved plate (33).

6. The SCR technology-based flue gas denitrification device for coal-fired power plants according to claim 1, characterized in that: The catalytic components (4) are provided with a plurality of groups which are layered at equal intervals in the upper and lower parts, and the drawer frame (41) is slidably inserted into the inner side of a guide rail provided on the inner wall of the selective catalytic reduction reactor (1).

7. The SCR technology-based flue gas denitrification device for coal-fired power plants according to claim 1, characterized in that: A plurality of placement grooves (43) of equal size and rectangular structure are provided on the inner side of the grid frame (44), a grid bottom plate (42) is provided at the bottom of the placement grooves (43), and the catalyst fillers are all placed in the placement grooves (43), and a handle (45) is provided on the front side of the drawer frame (41).

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