Efficient ammonia spraying device for SCR (Selective Catalytic Reduction) denitration

Abstract

The utility model discloses an efficient ammonia spraying device for SCR (Selective Catalytic Reduction) denitration, which is applied to the field of flue gas denitration and is characterized in that a preheater is connected with an ammonia spraying tower through pipelines, the two pipelines are respectively a first pipeline and a second pipeline, a reaction tower is communicated with the ammonia spraying tower, an ammonia spraying control mechanism is arranged in the ammonia spraying tower, and the ammonia spraying control mechanism is connected with the reaction tower. A catalyst layer is arranged in the reaction tower, and by arranging the preheater, the first pipeline, the second pipeline, the ammonia spraying tower, the reaction tower, the ammonia spraying control mechanism and the catalyst layer, in the using process, flue gas is preheated through the preheater and then is discharged into the ammonia spraying tower through the first pipeline and the second pipeline; due to the fact that the quality of the flue gas with the high NOX content is correspondingly high, the flue gas with the different NOX contents can enter the ammonia spraying tower through the first pipeline and the second pipeline respectively, then the ammonia spraying control mechanism can detect the NOX content in the first pipeline opening and the NOX content in the second pipeline opening, then different amounts of ammonia are sprayed out, and excessive use or insufficient use of the ammonia is avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of flue gas denitration, and particularly relates to a high-efficiency ammonia injection device for SCR denitration. Background Art

[0002] In the power industry, flue gas generated by coal-fired power plants, gas-fired power plants, combined cycle power stations, etc. contains a large amount of NOX. The working principle of the SCR denitration technology is to selectively reduce NOX in the flue gas into non-toxic and pollution-free N2 and H2O by using a reducing agent (such as ammonia water, liquid ammonia or urea) under certain temperature and the action of a catalyst.

[0003] At present, the Chinese utility model patent announced as CN220386226U discloses an ammonia injection control device for an SCR denitration system, which is provided with a control terminal, a first logic operation unit, a second logic operation unit, an outlet NOX concentration detector, a main PID controller, a sub-PID controller, a feedforward controller, an inlet NOX concentration correction device, an ammonia injection valve and an ammonia injection amount detector. The structure of this ammonia injection control device can realize the advance control of the ammonia injection valve, and then control the ammonia injection amount, so that the ammonia injection control of the denitration system can achieve the purpose of adapting to the change of working conditions.

[0004] This patent adopts a fixed ammonia injection strategy, ignoring the uneven spatial distribution of flue gas flow and NOX concentration, which easily leads to excessive or insufficient use of ammonia, and then affects the NOX removal efficiency and the stability of the system. Content of the Utility Model

[0005] The purpose of the utility model is to provide a high-efficiency ammonia injection device for SCR denitration, which solves the problems of the existing ammonia injection control device for SCR denitration system that adopts a fixed ammonia injection strategy, ignores the uneven spatial distribution of flue gas flow and NOX concentration, easily leads to excessive or insufficient use of ammonia, and then affects the NOX removal efficiency and the stability of the system.

[0006] The above technical purpose of the utility model is achieved by the following technical solutions. The high-efficiency ammonia injection device for SCR denitration includes a preheater, an ammonia injection tower and a reaction tower, and is characterized in that: the preheater and the ammonia injection tower are connected by pipelines, the number of the pipelines is two, namely a first pipeline and a second pipeline, the reaction tower is communicated with the ammonia injection tower, an ammonia injection control mechanism is arranged inside the ammonia injection tower, and a catalyst layer is arranged inside the reaction tower;

[0007] The ammonia injection control mechanism includes a partition baffle, a first NOX sensor, a second NOX sensor, a first ammonia injection grid, a second ammonia injection grid, a connecting pipe, an integrated ammonia evaporation and mixing system, and a control valve. The partition baffle is fixedly arranged inside the ammonia injection tower. The partition baffle is located between the first pipeline and the second pipeline. The cross-section of the partition baffle is L-shaped. The first NOX sensor is arranged inside the first pipeline. The second NOX sensor is arranged inside the second pipeline. The first ammonia injection grid is arranged inside the ammonia injection tower and is located between the partition baffle and the first pipeline. The second ammonia injection grid is arranged inside the ammonia injection tower and is located below the second pipeline. The number of connecting pipes is two, which are respectively arranged on the first ammonia injection grid and the second ammonia injection grid. The integrated ammonia evaporation and mixing system is arranged at the other end of the connecting pipe. The integrated ammonia evaporation and mixing system includes an ammonia evaporator and an ammonia / air mixer. The control valve is arranged on the connecting pipe.

[0008] With the above technical solution, by setting a preheater, a first pipeline, a second pipeline, an ammonia injection tower, a reaction tower, an ammonia injection control mechanism, and a catalyst layer, during use, first, the flue gas is preheated through the preheater, and then discharged into the ammonia injection tower through the first pipeline and the second pipeline. Since the flue gas with a high NOX content also has a relatively high mass, the flue gas with different NOX contents can enter the inside of the ammonia injection tower through the first pipeline and the second pipeline respectively. Then, the ammonia injection control mechanism can detect the NOX content at the ports of the first pipeline and the second pipeline, and then spray different amounts of ammonia to avoid overuse or shortage of ammonia. Then, after the flue gas is mixed with ammonia, it enters the reaction tower and reacts with the catalyst layer. The ammonia injection control mechanism includes a partition baffle, a first NOX sensor, a second NOX sensor, a first ammonia injection grid, a second ammonia injection grid, a connecting pipe, an integrated ammonia evaporation and mixing system, and a control valve. During use, first, the partition baffle separates the first pipeline and the second pipeline, so that the flue gas with different NOX contents enters from different pipelines. Then, according to the NOX concentration at the ports of the first pipeline and the second pipeline detected by the first NOX sensor and the second NOX sensor, the control valve controls the ammonia generated by the integrated ammonia evaporation and mixing system to be sprayed out from the first ammonia injection grid and the second ammonia injection grid through the connecting pipe and mixed with the flue gas, enabling the flue gas with different NOX contents to be mixed with different amounts of ammonia.

[0009] Furthermore: A fixed block is fixedly arranged inside the ammonia injection tower. An inlet channel is arranged inside the fixed block. The number of inlet channels is several and they are evenly arranged on the fixed block. An acceleration channel is arranged on the inlet channel. A spray channel is arranged on the acceleration channel. A rotating rod is rotatably connected inside the spray channel. Mixing plates are arranged on the rotating rod. The number of mixing plates is four and they are arranged circumferentially.

[0010] With the above technical solution, by setting the fixed block, inlet channel, acceleration channel, ejection channel, rotating rod and mixing plate, after the flue gas is mixed with ammonia, it can enter the acceleration channel from the inlet channel to increase the speed of the gas, and then be ejected from the ejection channel. The force of the ejected gas acts on the mixing plate, driving the rotating rod to rotate, and further causing the mixing plate to rotate, further enhancing the mixing effect of the flue gas and ammonia.

[0011] Furthermore: A deflector plate is fixedly arranged at the inner top of the ammonia injection tower, and the number of the deflector plates is several and they are evenly arranged.

[0012] With the above technical solution, by setting the deflector plate, after the flue gas and ammonia are fully mixed, the gas can be guided into the reaction tower through the deflector plate to react with the catalyst layer in the reaction tower.

[0013] Furthermore: A controller is arranged on the ammonia injection tower, and the controller is electrically connected to the first NOX sensor, the second NOX sensor, the integrated ammonia evaporation and mixing system and the control valve.

[0014] With the above technical solution, by setting the controller, during use, the controller can control the first NOX sensor, the second NOX sensor, the integrated ammonia evaporation and mixing system and the control valve.

[0015] Furthermore: Two outlet pipes are arranged on the reaction tower and are symmetrically arranged.

[0016] With the above technical solution, by setting the outlet pipes, after the flue gas treatment is completed, it can be discharged through the outlet pipes.

[0017] Furthermore: A cross plate is fixedly connected to the lower end of the reaction tower, and support columns are arranged on the cross plate, and the support columns are used to provide a supporting effect for the preheater and the ammonia injection tower.

[0018] With the above technical solution, by setting the cross plate and the support columns, during use, the cross plate can increase the stability of the reaction tower, and then the support columns can provide a supporting effect for the preheater and the ammonia injection tower.

[0019] Furthermore: A fixing seat for improving stability is arranged on the surface of the integrated ammonia evaporation and mixing system.

[0020] With the above technical solution, by setting the fixing seat, during use, the fixing seat can improve the stability of the integrated ammonia evaporation and mixing system.

[0021] Furthermore: A heater is arranged at the inner top of the reaction tower.

[0022] With the above technical solution, by setting up a heater, the heater can raise the temperature of the mixed gas of flue gas and ammonia, enabling better reaction with the catalyst layer.

[0023] In summary, the present utility model has the following beneficial effects:

[0024] By setting up an ammonia injection control mechanism, first, the partition baffle separates the first pipeline and the second pipeline, allowing flue gas with different NOX contents to enter from different pipelines. Then, according to the NOX concentrations detected by the first NOX sensor and the second NOX sensor at the outlets of the first pipeline and the second pipeline, the ammonia generated by the integrated ammonia evaporation and mixing system is controlled by the control valve to be sprayed out from the first ammonia injection grid and the second ammonia injection grid through the connecting pipe, and mixed with the flue gas, enabling the flue gas with different NOX contents to be mixed with different amounts of ammonia.

[0025] By setting up a fixed block, an inlet channel, an acceleration channel, a spray channel, a rotating rod, and a mixing plate, after the flue gas and ammonia are mixed, they can enter the acceleration channel from the inlet channel to increase the speed of the gas, and then be sprayed out from the spray channel. The force of the gas spray acts on the mixing plate, driving the rotating rod to rotate, and further causing the mixing plate to rotate, further enhancing the mixing effect of the flue gas and ammonia.

[0026] Based on the above improvement points, the overall technical effect achieved by this device is to mix flue gas with different NOX contents with different amounts of ammonia, avoiding the situation of excessive or insufficient use of ammonia. Description of the Drawings

[0027] Figure 1 is the overall structural schematic diagram of the present utility model;

[0028] Figure 2 is the left view of the present utility model;

[0029] Figure 3 is the Figure 2 three-dimensional sectional view at A - A of the present utility model;

[0030] Figure 4 is the structural schematic diagram of the first ammonia injection grid, the second ammonia injection grid, and the connecting pipe of the present utility model;

[0031] Figure 5 is the Figure 3 enlarged view at A of the present utility model.

[0032] In the figure, 1 is a preheater; 2 is an ammonia injection tower; 3 is a reaction tower; 4 is a first pipeline; 5 is a second pipeline; 6 is an ammonia injection control mechanism; 7 is a catalyst layer; 8 is a fixing block; 9 is an inlet channel; 10 is an acceleration channel; 11 is an ejection channel; 12 is a rotating rod; 13 is a mixing plate; 14 is a guiding plate; 15 is a controller; 16 is an outlet pipe; 17 is a horizontal plate; 18 is a support column; 19 is a fixing seat; 20 is a heater; 601 is a partition baffle; 602 is a first NOX sensor; 603 is a second NOX sensor; 604 is a first ammonia injection grid; 605 is a second ammonia injection grid; 606 is a connecting pipe; 607 is an integrated ammonia evaporation and mixing system; 608 is a control valve. Detailed implementation mode

[0033] The present utility model will be further described in detail below with reference to the accompanying drawings.

[0034] Embodiment:

[0035] Please refer to Figures 1 - 5 , the present utility model provides a technical solution: an SCR denitration high-efficiency ammonia injection device, including a preheater 1, an ammonia injection tower 2 and a reaction tower 3. The preheater 1 and the ammonia injection tower 2 are connected by pipelines. The number of pipelines is two, namely a first pipeline 4 and a second pipeline 5. The reaction tower 3 is communicated with the ammonia injection tower 2. An ammonia injection control mechanism 6 is arranged inside the ammonia injection tower 2, and a catalyst layer 7 is arranged inside the reaction tower 3;

[0036] The ammonia injection control mechanism 6 includes a partition baffle 601, a first NOX sensor 602, a second NOX sensor 603, a first ammonia injection grid 604, a second ammonia injection grid 605, a connecting pipe 606, an integrated ammonia evaporation and mixing system 607 and a control valve 608. The partition baffle 601 is fixedly arranged inside the ammonia injection tower 2. The partition baffle 601 is located between the first pipeline 4 and the second pipeline 5. The cross-section of the partition baffle 601 is L-shaped. The first NOX sensor 602 is arranged inside the first pipeline 4, and the second NOX sensor 603 is arranged inside the second pipeline 5. The first ammonia injection grid 604 is arranged inside the ammonia injection tower 2 and is located between the partition baffle 601 and the first pipeline 4. The second ammonia injection grid 605 is arranged inside the ammonia injection tower 2 and is located below the second pipeline 5. The number of connecting pipes 606 is two, which are respectively arranged on the first ammonia injection grid 604 and the second ammonia injection grid 605. The integrated ammonia evaporation and mixing system 607 is arranged at the other end of the connecting pipe 606. The integrated ammonia evaporation and mixing system 607 includes an ammonia evaporator and an ammonia / air mixer. The control valve 608 is arranged on the connecting pipe 606.

[0037] By setting up a preheater 1, a first pipeline 4, a second pipeline 5, an ammonia injection tower 2, a reaction tower 3, an ammonia injection control mechanism 6, and a catalyst layer 7, during use, first, the flue gas is preheated through the preheater 1, and then discharged into the ammonia injection tower 2 through the first pipeline 4 and the second pipeline 5. Since the flue gas with a high NOX content also has a relatively high mass, the flue gas with different NOX contents can enter the interior of the ammonia injection tower 2 through the first pipeline 4 and the second pipeline 5 respectively. Then, the ammonia injection control mechanism 6 can detect the NOX content at the mouths of the first pipeline 4 and the second pipeline 5, and then spray different amounts of ammonia to avoid overuse or insufficiency of ammonia. Then, after the flue gas is mixed with ammonia, it enters the reaction tower 3 and reacts with the catalyst layer 7;

[0038] Among them, the ammonia injection control mechanism 6 includes a partition baffle 601, a first NOX sensor 602, a second NOX sensor 603, a first ammonia injection grid 604, a second ammonia injection grid 605, a connecting pipe 606, an integrated ammonia evaporation and mixing system 607, and a control valve 608. During use, first, the partition baffle 601 separates the first pipeline 4 and the second pipeline 5, so that the flue gas with different NOX contents enters from different pipelines. Then, according to the NOX concentrations at the mouths of the first pipeline 4 and the second pipeline 5 detected by the first NOX sensor 602 and the second NOX sensor 603, the control valve 608 is used to control the ammonia generated by the integrated ammonia evaporation and mixing system 607 to be sprayed out from the first ammonia injection grid 604 and the second ammonia injection grid 605 through the connecting pipe 606 and mixed with the flue gas, enabling the flue gas with different NOX contents to be mixed with different amounts of ammonia.

[0039] Reference Figure 5 Inside the ammonia injection tower 2, a fixed block 8 is fixedly arranged. An inlet channel 9 is arranged inside the fixed block 8. The number of inlet channels 9 is several and they are evenly arranged on the fixed block 8. An acceleration channel 10 is arranged on the inlet channel 9. A spray channel 11 is arranged on the acceleration channel 10. A rotating rod 12 is rotatably connected inside the spray channel 11. A mixing plate 13 is arranged on the rotating rod 12. The number of mixing plates 13 is four and they are arranged circumferentially. By setting up the fixed block 8, the inlet channel 9, the acceleration channel 10, the spray channel 11, the rotating rod 12, and the mixing plate 13, after the flue gas is mixed with ammonia, it can enter the acceleration channel 10 from the inlet channel 9 to increase the speed of the gas, and then be sprayed out from the spray channel 11. The force of the gas spray acts on the mixing plate 13, driving the rotating rod 12 to rotate, and further causing the mixing plate 13 to rotate, further enhancing the mixing effect of the flue gas and ammonia.

[0040] Reference Figure 3, a flow guide plate 14 is fixedly arranged at the inner top of the ammonia injection tower 2. The number of the flow guide plates 14 is several and they are evenly arranged. By arranging the flow guide plate 14, after the flue gas and ammonia are fully mixed, the gas can be introduced into the reaction tower 3 through the flow guide plate 14 to react with the catalyst layer 7 in the reaction tower 3.

[0041] Reference Figure 1 , a controller 15 is arranged on the ammonia injection tower 2. The controller 15 is electrically connected to the first NOX sensor 602, the second NOX sensor 603, the integrated ammonia evaporation and mixing system 607 and the control valve 608. By arranging the controller 15, during use, the controller 15 can control the first NOX sensor 602, the second NOX sensor 603, the integrated ammonia evaporation and mixing system 607 and the control valve 608.

[0042] Reference Figure 1 , two outlet pipes 16 are arranged on the reaction tower 3 and are symmetrically arranged. By arranging the outlet pipes 16, after the flue gas treatment is completed, it can be discharged through the outlet pipes 16.

[0043] Reference Figure 1 , a cross plate 17 is fixedly connected to the lower end of the reaction tower 3. Support columns 18 are arranged on the cross plate 17. The support columns 18 are used to provide a supporting effect on the preheater 1 and the ammonia injection tower 2. By arranging the cross plate 17 and the support columns 18, during use, the cross plate 17 can increase the stability of the reaction tower 3, and then the support columns 18 can provide a supporting effect on the preheater 1 and the ammonia injection tower 2.

[0044] Reference Figure 1 , a fixing seat 19 for improving stability is arranged on the surface of the integrated ammonia evaporation and mixing system 607. By arranging the fixing seat 19, during use, the fixing seat 19 can improve the stability of the integrated ammonia evaporation and mixing system 607.

[0045] Reference Figure 3 , a heater 20 is arranged at the inner top of the reaction tower 3. By arranging the heater 20, the heater 20 can increase the temperature of the mixed gas of the flue gas and ammonia, and can react better with the catalyst layer 7.

[0046] Brief description of the use process:

[0047] In use, first, the flue gas is preheated by the preheater 1, and then discharged into the ammonia injection tower 2 through the first pipeline 4 and the second pipeline 5. Since the flue gas with a high NOX content also has a relatively high mass, the flue gas with different NOX contents can enter the interior of the ammonia injection tower 2 through the first pipeline 4 and the second pipeline 5 respectively. The partition baffle 601 separates the first pipeline 4 and the second pipeline 5, enabling the flue gas with different NOX contents to enter from different pipelines. Then, according to the NOX concentrations at the inlets of the first pipeline 4 and the second pipeline 5 detected by the first NOX sensor 602 and the second NOX sensor 603, the control valve 608 controls the ammonia gas generated by the integrated ammonia evaporation and mixing system 607 to be ejected from the first ammonia injection grid 604 and the second ammonia injection grid 605 through the connecting pipe 606 and mixed with the flue gas, enabling the flue gas with different NOX contents to be mixed with different amounts of ammonia gas (the first NOX sensor 602 and the second NOX sensor 603 are directly applied in this application and not within the protection scope of this application. Their reference models can be: 5WK97103);

[0048] Then, after the flue gas is mixed with ammonia gas, it can enter the acceleration channel 10 from the inlet channel 9 to increase the speed of the gas, and then be ejected from the ejection channel 11. The force of the ejected gas acts on the mixing plate 13, driving the rotating rod 12 to rotate, and further causing the mixing plate 13 to rotate, further enhancing the mixing effect of the flue gas and ammonia gas. After the flue gas and ammonia gas are fully mixed, the deflector 14 can guide the gas into the reaction tower 3 to react with the catalyst layer 7 in the reaction tower 3. After the flue gas treatment is completed, it can be discharged through the outlet pipe 16;

[0049] Finally, the cross plate 17 can increase the stability of the reaction tower 3, and then the support column 18 can provide a supporting effect for the preheater 1 and the ammonia injection tower 2, and the fixing seat 19 can improve the stability of the integrated ammonia evaporation and mixing system 607.

[0050] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. An SCR denitration high-efficiency ammonia injection device, comprising a preheater (1), an ammonia injection tower (2) and a reaction tower (3), characterized in that: The preheater (1) and the ammonia injection tower (2) are connected by pipelines, the number of the pipelines being two, namely a first pipeline (4) and a second pipeline (5); the reaction tower (3) is connected to the ammonia injection tower (2); an ammonia injection control mechanism (6) is provided inside the ammonia injection tower (2); and a catalyst layer (7) is provided inside the reaction tower (3); The ammonia injection control mechanism (6) comprises a partition baffle (601), a first NOx sensor (602), a second NOx sensor (603), a first ammonia injection grid (604), a second ammonia injection grid (605), a connecting pipe (606), an integrated ammonia evaporation mixing system (607) and a control valve (608), wherein the partition baffle (601) is fixedly arranged inside the ammonia injection tower (2), the partition baffle (601) is located between the first pipeline (4) and the second pipeline (5), and the cross section of the partition baffle (601) is L-shaped, the first NOx sensor (602) is arranged inside the first pipeline (4), and the second NOx sensor (603) is arranged inside the first pipeline (4). The first ammonia spraying grid (604) is arranged inside the ammonia spraying tower (2) and is located between the partition baffle (601) and the first pipeline (4); the second ammonia spraying grid (605) is arranged inside the ammonia spraying tower (2) and is located below the second pipeline (5); the number of the connecting pipes (606) is two and they are arranged on the first ammonia spraying grid (604) and the second ammonia spraying grid (605) respectively; the integrated ammonia evaporation and mixing system (607) is arranged at the other end of the connecting pipe (606); the integrated ammonia evaporation and mixing system (607) includes an ammonia evaporator and an ammonia-air mixer; and the control valve (608) is arranged on the connecting pipe (606).

2. The SCR denitration high-efficiency ammonia injection device according to claim 1 is characterized in that: A fixed block (8) is fixedly arranged inside the ammonia spray tower (2), an inlet channel (9) is arranged inside the fixed block (8), the inlet channels (9) are in a plurality and are evenly arranged on the fixed block (8), an acceleration channel (10) is arranged on the inlet channel (9), an ejection channel (11) is arranged on the acceleration channel (10), a rotating rod (12) is rotatably connected inside the ejection channel (11), a mixing plate (13) is arranged on the rotating rod (12), and the mixing plates (13) are in four numbers and are arranged in a circle.

3. The SCR denitration high-efficiency ammonia injection device according to claim 1 is characterized in that: A guide plate (14) is fixedly arranged on the inner top of the ammonia injection tower (2), and the guide plates (14) are multiple and evenly arranged.

4. The SCR denitration high-efficiency ammonia injection device according to claim 1 is characterized in that: The ammonia injection tower (2) is provided with a controller (15), and the controller (15) is electrically connected to the first NOx sensor (602), the second NOx sensor (603), the integrated ammonia evaporation and mixing system (607) and the control valve (608).

5. The SCR denitration high-efficiency ammonia injection device according to claim 1 is characterized in that: The reaction tower (3) is provided with an air outlet pipe (16), and the number of the air outlet pipes (16) is two and they are symmetrically arranged.

6. The SCR denitration high-efficiency ammonia injection device according to claim 1 is characterized in that: The lower end of the reaction tower (3) is fixedly connected to a transverse plate (17), and a support column (18) is arranged on the transverse plate (17). The support column (18) is used to provide support for the preheater (1) and the ammonia injection tower (2).

7. The SCR denitration high-efficiency ammonia injection device according to claim 1 is characterized in that: A fixing seat (19) for improving stability is arranged on the surface of the integrated ammonia evaporation and mixing system (607).

8. The SCR denitration high-efficiency ammonia injection device according to claim 1 is characterized in that: A heater (20) is provided at the inner top of the reaction tower (3).

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