Method for reducing ammonia water consumption and ammonia escape in cement kiln SNCR (selective non-catalytic reduction) denitration

Abstract

The invention discloses a method for reducing ammonia water consumption and ammonia escape for cement kiln SNCR (selective non-catalytic reduction) denitration, which comprises the following steps of: accurately selecting the position of an SNCR denitration spray gun through computer simulation aided design, positioning the position of the spray gun at the conical part of a decomposing furnace, spraying flue gas entering into the decomposing furnace by the spray gun at the conical part of the decomposing furnace for denitration, and enabling the denitrated flue gas to enter into the decomposing furnace for denitration; when NOx is discharged, the NOx can flow along the inside of the decomposing furnace and is denitrated under the action of the other spray guns, quicker denitration is ensured, a set of SNCR secondary precise distribution system is additionally arranged, three ammonia water conveying pipelines are laid, each group of spray gun flow adjusting device is additionally arranged, and computer simulation and field detection verification show that the NOx distribution at the section of the decomposing furnace is very non-uniform. And more ammonia water needs to be sprayed in an area with high NOx concentration, otherwise, less ammonia water needs to be sprayed, so that the flow of each group of spray guns is required to be adjustable, the utilization rate of the ammonia water can be improved by reasonably adjusting the flow of each gun, and the denitration efficiency can also be improved.

Description

Technical Field

[0001] The invention relates to the field of cement kiln denitration, and in particular to a method for reducing ammonia water consumption and ammonia escape in cement kiln SNCR denitration. Background Art

[0002] SNCR is a technology commonly used in cement kiln denitrification. It reduces nitrogen oxide (NOx) emissions by adding NH3 (ammonia) or urea to the combustion process. The existing SNCR control system spray guns are located in the cone of the C5 cyclone, and 6 are set in the cone of C5A / C5B, totaling 12 spray guns. The spray guns use multi-hole spray guns with different lengths (4 long guns + 8 short guns). Currently, NOx is controlled within 100mg / Nm3. Under limited production conditions, the average ammonia consumption is 850kg / h. Under full production conditions, the average ammonia consumption is 1100kg / h. If NOx is controlled below 50mg / Nm3, the average ammonia consumption exceeds 2000kg / h, and it still cannot stably meet the emission index below 50mg / Nm3. The temperature at the front end of the gooseneck is about 897℃, and the C5 outlet temperature is about 892℃.

[0003] In the process of utilizing ammonia water for denitrification, ammonia water needs to react quickly with the nitric acid to be reacted. In order to better enable ammonia water to directly react with nitric acid after being sprayed out, atomized ammonia water is sprayed out by a spray gun. The atomized ammonia water increases the contact area with nitric acid and can better react with nitric acid. However, the atomized ammonia water sprayed out by the existing spray gun is effective in a range and cannot be adjusted. It can only be sprayed in a single direction and a single range, which is not conducive to better reaction between ammonia water and nitric acid. Summary of the invention

[0004] The object of the present invention is to provide a method for reducing the amount of ammonia water used and reducing ammonia escape in SNCR denitration of cement kilns, so as to solve the above technical problems.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The method for reducing ammonia consumption and ammonia escape for SNCR denitration in cement kiln comprises the following steps:

[0007] S1: Accurately select the installation position of the spray gun. According to the preliminary test results and the analysis of the on-site conditions, the final installation position of the spray gun is determined through CFD flow field simulation and further detection and analysis of the furnace atmosphere. By optimizing the position of the spray gun, the SNCR can be operated under the optimal temperature and atmosphere conditions, which can greatly improve the denitrification efficiency of the SNCR. In the later stage, special computer simulation and detection analysis will be provided for individual projects;

[0008] S2: A new SNCR secondary precision distribution system is added, including a control system and five flow distribution systems, to achieve precise control of the flow of three-layer spray guns at the outlet of the decomposition furnace gooseneck tube, the C5 straight tube part, and the outlet of the C5 tube, and automatic adjustment of the flow distribution ratio of each set. The outlet of the decomposition furnace gooseneck tube is equipped with 8 spray guns, the straight section of the C5A / B tube is equipped with 6 spray guns, and the outlet of the C5A / B tube is equipped with 4 spray guns, a total of 28 spray guns;

[0009] S3: Lay three ammonia water delivery pipelines to deliver ammonia water from the distribution cabinet to the gooseneck outlet of the decomposition furnace, the C5 straight tube, and the C5 outlet flue injection layer;

[0010] S4: The whole system consists of 5 modules and 4 control cabinets, among which the decomposition furnace gooseneck outlet module is provided with a control cabinet 1, the C5A straight section module is provided with a control cabinet 2, the C5B straight section module is provided with a control cabinet 3, and the C5A outlet and C5B outlet modules share a control cabinet 4. Each module can be automatically controlled separately, and the frequency of the regulating valve and pump can be automatically controlled through temperature and atmosphere;

[0011] S5: Add a flow rate regulating device for each group of spray guns. Through computer simulation and on-site test verification, it is found that the NOx distribution in the cross section of the decomposition furnace is very uneven. The area with high NOx concentration needs to spray more ammonia water, and vice versa. This requires that the flow rate of each group of spray guns can be adjusted. Reasonable adjustment of the flow rate of each gun can improve the utilization rate of ammonia water and the denitrification efficiency.

[0012] S7: The opening position of the spray gun is located according to the simulation results;

[0013] S8: Add an intelligent flue gas denitrification automatic control system to realize autonomous and stable operation of the denitrification system. The flow rate of each module spray gun can be independently and automatically distributed according to temperature changes. The system is developed based on the PID++ intelligent control system platform. The core of the control system is the neural network model. Many related variables are introduced into the model, such as the amount of ammonia sprayed by the decomposition furnace, secondary air temperature, NOx content at the outlet of the decomposition furnace / first-stage barrel, O2 content at the outlet of the decomposition furnace / first-stage barrel, and coal feeding amount of the decomposition furnace. The model prediction is used to eliminate the influence caused by long time lag.

[0014] A spray gun used in a method for reducing ammonia consumption and ammonia escape in SNCR denitrification of a cement kiln comprises a ventilation hood, characterized in that: a fixed column is fixedly connected inside the ventilation hood, a liquid inlet pipe is slidably connected inside the fixed column, a nozzle is threadedly connected to the fixed column, a mounting cover is fixedly connected to the nozzle, a first liquid infusion pipe is fixedly connected to the mounting cover, the first liquid infusion pipe is connected to the liquid inlet pipe, an impact atomization mechanism is fixedly connected to the bottom of the first liquid infusion pipe, a second liquid infusion pipe is fixedly connected to the right side of the liquid inlet pipe, a ventilation mechanism is fixedly connected to the second liquid infusion pipe, and the ventilation mechanism is connected to the liquid inlet pipe through the second liquid infusion pipe.

[0015] Preferably, the nozzle includes a threaded tube, the threaded tube is threadedly connected to the fixing column, the threaded tube is fixedly connected to the mounting cover, a sliding groove is provided on the threaded tube, a sealing block is slidingly connected inside the sliding groove, the sealing block is fixedly connected to the liquid inlet pipe, a second air inlet groove is provided inside the threaded tube and the mounting cover, a third air inlet groove is provided inside the sealing block, and a first air inlet groove is provided inside the fixing column.

[0016] Preferably, valves are installed on the first infusion tube and the second infusion tube, the parts of the first infusion tube and the second infusion tube located above the fixed column are hoses, and the parts of the first infusion tube and the second infusion tube located on the left and right sides of the ventilation hood are fixedly connected to the ventilation hood.

[0017] Preferably, the ventilation mechanism includes a first rotating ring, which is rotatably connected to a fixed column, a plurality of positioning components are fixedly connected to the first rotating ring, a first ventilation groove is provided on the first rotating ring, a plurality of latch teeth are fixedly connected to the first rotating ring, a first gear is meshed with the latch teeth, a first driving shaft is fixedly connected to the first gear, a first hollow box is rotatably connected to the first driving shaft, the first hollow box is fixedly connected to the ventilation cover, an impeller is provided inside the first hollow box, the impeller is fixedly connected to the first driving shaft, the first hollow box is fixedly connected to the second infusion tube, a second rotating ring is provided below the first rotating ring, a plurality of latch grooves are provided on the second rotating ring, the second rotating ring is fixedly connected to the ventilation cover and the fixed column, a second ventilation groove is penetrated through the second rotating ring, and a slot is provided on the second rotating ring.

[0018] Preferably, the positioning assembly includes a positioning tube, the positioning tube is fixedly connected to the first rotating ring, a slide is slidably connected inside the positioning tube, the top of the slide is connected to the positioning tube via a spring, the bottom of the slide is fixedly connected to an insert block, and the insert block is plugged into the slot.

[0019] Preferably, the impact atomization mechanism includes a fixed box, a rotating member is fixedly connected inside the fixed box, a first rotating rod is rotatably connected to the rotating member, a third gear is fixedly connected to the first rotating rod, a connecting plate is fixedly connected to the first rotating rod, a second auxiliary ring is fixedly connected to the connecting plate, a second rotating disk is rollingly connected to the second auxiliary ring, the second rotating disk is fixedly connected to the second rotating rod, the second rotating rod is fixedly connected to the second gear, the second gear is meshed with the third gear, the second rotating rod is fixedly connected to the first rotating disk, a first auxiliary ring is arranged above the first rotating disk, the first auxiliary ring is fixedly connected to the fixed box, the first auxiliary ring is rotatably connected to the first rotating disk, a rotating sleeve is rotatably connected to the bottom end of the second rotating rod, a connecting seat is fixedly connected to the rotating sleeve, a first pulley is fixedly connected to the bottom of the connecting seat, a rotating column is fixedly connected to the bottom of the first pulley, the rotating column is rotatably connected to the fixed box, the first rotating rod is fixedly connected to the second pulley, and the first pulley and the second pulley are connected by a connecting belt.

[0020] Preferably, an impact plate is fixedly connected to the top of the second rotating rod, and a plurality of protrusions are fixedly connected to the top of the impact plate, and the plurality of protrusions have different shapes.

[0021] Preferably, a second hollow box is fixedly connected to the bottom of the fixed box, a second driving shaft is rotatably connected to the second hollow box, the second driving shaft is fixedly connected to the rotating column, an impeller is provided inside the second hollow box, the impeller is fixedly connected to the second driving shaft, a third infusion tube is fixedly connected to one end of the second hollow box, the third infusion tube is communicated with the first infusion tube, and a fourth infusion tube is fixedly connected to the other end of the second hollow box.

[0022] The beneficial effects of the present invention are:

[0023] 1. The present invention uses computer simulation-assisted design to accurately select the position of the SNCR denitrification spray gun, and positions the spray gun at the cone of the decomposition furnace, so that the incoming flue gas is first sprayed with flue gas by the spray gun at the cone of the decomposition furnace for denitrification, and the flue gas after denitrification will also flow along the inside of the decomposition furnace and be denitrified by the remaining spray guns, ensuring faster denitrification.

[0024] 2. By opening the valve on the second infusion tube, the ammonia water input by the liquid inlet tube can be used to drive the first driving shaft, thereby rotating the first rotating ring, so that the first ventilation groove on the first rotating ring and the second ventilation groove on the second rotating ring will be connected, so that the gas introduced into the ventilation hood will be sprayed out along the fixed column and the mounting hood through the first ventilation groove and the second ventilation groove to form an air wall, which can effectively control the range of ammonia water atomization, and by pulling the liquid inlet tube, the liquid inlet tube drives the blocking block to move. The blocking block is located at different positions, and different air inlet slots can be controlled to discharge air, thereby forming wind walls of different sizes, which can further control the spray range of ammonia water and allow the atomized ammonia water to react with nitric acid according to needs.

[0025] 3. By opening the valve on the first infusion tube, the ammonia water inputted by the liquid inlet tube can be used to drive the second drive shaft, so that the second drive shaft not only drives the third gear to rotate, but also drives the second rotating rod to rotate. The rotation of the second rotating rod will drive the impact plate to rotate. The impact plate is provided with a plurality of protrusions of different shapes. In this way, after the high-pressure ammonia water in the liquid inlet tube is sprayed out, it will not only collide with different protrusions to be atomized, but also because the inclination angle of the impact plate is constantly changing, the angle of the flow direction of the atomized ammonia water after the spraying will also change. In this way, it can effectively prevent the ammonia water from being sprayed only in one place, and the rotation of the third gear will also cause the second rotating rod to rotate. In this way, the impact plate will rotate, and the rotating impact plate can further throw away the ammonia water that has been atomized by the impact, so that its diffusion range is larger. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The velocity distribution diagram of each cross section of the decomposition furnace and C5 of the present invention;

[0027] Figure 2 The NOx concentration distribution diagram of the decomposition furnace cross section of the present invention;

[0028] Figure 3 It is a structural schematic diagram of the spray gun of the present invention;

[0029] Figure 4 It is a schematic diagram of the internal structure of the spray gun of the present invention;

[0030] Figure 5 for Figure 4 A magnified schematic diagram of part A;

[0031] Figure 6 for Figure 4 An enlarged schematic diagram of part B;

[0032] Figure 7 for Figure 4 An enlarged schematic diagram of the C portion;

[0033] Figure 8 It is a schematic diagram of the connection between the first rotating ring and the second rotating ring of the present invention;

[0034] Fig. 9 It is a structural schematic diagram of the limit assembly of the present invention;

[0035] Fig.10 It is a schematic diagram of the internal structure of the first hollow box of the present invention;

[0036] Fig.11 It is a structural schematic diagram of the impact atomization mechanism of the present invention.

[0037] Figure numerals: 1, liquid inlet pipe; 2, ventilation cover; 3, first infusion pipe; 4, second infusion pipe; 5, mounting cover; 6, fixing column; 7, first air inlet groove; 8, threaded pipe; 10, slide groove; 12, second air inlet groove; 13, third air inlet groove; 14, blocking block; 15, latching tooth; 16, first driving shaft; 17, first gear; 18, first hollow box; 19, first rotating ring; 20, positioning pipe; 21, first ventilation groove; 23, latching groove; 24, second ventilation groove; 25, second rotating ring; 26, spring; 27, slide plate; 28 , plug; 29, impeller; 30, fixed box; 31, bump; 32, impact plate; 33, fourth infusion tube; 34, second hollow box; 35, third infusion tube; 36, first rotating rod; 37, second rotating rod; 38, first rotating disk; 39, first auxiliary ring; 40, second gear; 41, second rotating disk; 42, second auxiliary ring; 43, third gear; 44, connecting seat; 45, first pulley; 46, rotating column; 47, rotating sleeve; 48, connecting belt; 49, second pulley; 50, rotating member; 51, connecting plate. DETAILED DESCRIPTION

[0038] In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments and drawings, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0039] The specific embodiments of the present invention are described below with reference to the accompanying drawings.

[0040] Embodiment 1:

[0041] like Figure 1-11 As shown, the method for reducing ammonia consumption and ammonia escape in SNCR denitrification of cement kiln comprises the following steps:

[0042] S1: Accurately select the installation position of the spray gun. According to the preliminary test results and the analysis of the on-site conditions, the final installation position of the spray gun is determined through CFD calculation flow field simulation and further detection and analysis of the atmosphere in the furnace (the position of the spray gun is located in the cone of the decomposition furnace). By optimizing the position of the spray gun, the SNCR can be operated under the optimal temperature and atmosphere conditions, which can greatly improve the denitrification efficiency of the SNCR. In the later stage, special computer simulation and detection analysis will be provided for individual projects;

[0043] S2: A new SNCR secondary precision distribution system is added, including a control system and five flow distribution systems, to achieve precise control of the flow of three-layer spray guns at the outlet of the decomposition furnace gooseneck tube, the C5 straight tube part, and the outlet of the C5 tube, and automatic adjustment of the flow distribution ratio of each set. The outlet of the decomposition furnace gooseneck tube is equipped with 8 spray guns, the straight section of the C5A / B tube is equipped with 6 spray guns, and the outlet of the C5A / B tube is equipped with 4 spray guns, a total of 28 spray guns;

[0044] S3: Lay three ammonia water delivery pipelines to deliver ammonia water from the distribution cabinet to the gooseneck outlet of the decomposition furnace, the C5 straight tube, and the C5 outlet flue injection layer;

[0045] S4: The whole system consists of 5 modules and 4 control cabinets, among which the decomposition furnace gooseneck outlet module is provided with a control cabinet 1, the C5A straight section module is provided with a control cabinet 2, the C5B straight section module is provided with a control cabinet 3, and the C5A outlet and C5B outlet modules share a control cabinet 4. Each module can be automatically controlled separately, and the frequency of the regulating valve and pump can be automatically controlled through temperature and atmosphere;

[0046] S5: Add a flow rate regulating device for each group of spray guns. Through computer simulation and on-site test verification, it is found that the NOx distribution in the cross section of the decomposition furnace is very uneven. The area with high NOx concentration needs to spray more ammonia water, and vice versa. This requires that the flow rate of each group of spray guns can be adjusted. Reasonable adjustment of the flow rate of each gun can improve the utilization rate of ammonia water and the denitrification efficiency.

[0047] S7: The opening position of the spray gun is located according to the simulation results;

[0048] S8: Add an intelligent flue gas denitrification automatic control system to realize autonomous and stable operation of the denitrification system. The flow rate of each module spray gun can be independently and automatically distributed according to temperature changes. The system is developed based on the PID++ intelligent control system platform. The core of the control system is the neural network model. Many related variables are introduced into the model, such as the amount of ammonia sprayed by the decomposition furnace, secondary air temperature, NOx content at the outlet of the decomposition furnace / first-stage barrel, O2 content at the outlet of the decomposition furnace / first-stage barrel, and coal feeding amount of the decomposition furnace. The model prediction is used to eliminate the influence caused by long time lag.

[0049] Embodiment 2:

[0050] like Figure 3-11 As shown, when other parts are the same as those in Example 1, the difference between this embodiment and Example 1 is that: a spray gun in a method for reducing ammonia water consumption and ammonia escape in SNCR denitration of a cement kiln comprises a ventilation hood 2, a fixed column 6 is fixedly connected inside the ventilation hood 2, a liquid inlet pipe 1 is slidably connected inside the fixed column 6, a nozzle is threadedly connected to the fixed column 6, a mounting hood 5 is fixedly connected to the nozzle, a first liquid infusion pipe 3 is fixedly connected to the mounting hood 5, the first liquid infusion pipe 3 is connected to the liquid inlet pipe 1, an impact atomization mechanism is fixedly connected to the bottom of the first liquid infusion pipe 3, a second liquid infusion pipe 4 is fixedly connected to the right side of the liquid infusion pipe 1, a ventilation mechanism is fixedly connected to the second liquid infusion pipe 4, and the ventilation mechanism is connected to the liquid inlet pipe 1 through the second liquid infusion pipe 4;

[0051] The nozzle includes a threaded tube 8, which is threadedly connected to the fixing column 6, and the threaded tube 8 is fixedly connected to the mounting cover 5. A slide groove 10 is provided on the threaded tube 8, and a blocking block 14 is slidably connected inside the slide groove 10. The blocking block 14 is fixedly connected to the liquid inlet pipe 1, and a second air inlet groove 12 is provided inside the threaded tube 8 and the mounting cover 5, and a third air inlet groove 13 is provided inside the blocking block 14, and a first air inlet groove 7 is provided inside the fixing column 6;

[0052] Valves are installed on the first infusion tube 3 and the second infusion tube 4. The parts of the first infusion tube 3 and the second infusion tube 4 located above the fixed column 6 are hoses. The parts of the first infusion tube 3 and the second infusion tube 4 located on the left and right sides of the ventilation cover 2 are fixedly connected to the ventilation cover 2.

[0053] The ventilation mechanism includes a first rotating ring 19, which is rotatably connected to the fixed column 6, a plurality of positioning components are fixedly connected to the first rotating ring 19, a first ventilation groove 21 is provided on the first rotating ring 19, a plurality of latch teeth 15 are fixedly connected to the first rotating ring 19, a first gear 17 is meshed on the latch teeth 15, a first driving shaft 16 is fixedly connected to the first gear 17, a first hollow box 18 is rotatably connected to the first driving shaft 16, the first hollow box 18 is fixedly connected to the ventilation cover 2, an impeller 29 is arranged inside the first hollow box 18, the impeller 29 is fixedly connected to the first driving shaft 16, the first hollow box 18 is fixedly connected to the second infusion tube 4, a second rotating ring 25 is arranged below the first rotating ring 19, a plurality of latch grooves 23 are provided on the second rotating ring 25, the second rotating ring 25 is fixedly connected to the ventilation cover 2 and the fixed column 6, a second ventilation groove 24 is penetrated through the second rotating ring 25, and a slot is provided on the second rotating ring 25;

[0054] The positioning assembly includes a positioning tube 20, which is fixedly connected to the first rotating ring 19, a slide plate 27 is slidably connected inside the positioning tube 20, the top of the slide plate 27 is connected to the positioning tube 20 through a spring 26, and an insert block 28 is fixedly connected to the bottom of the slide plate 27, and the insert block 28 is plugged into the card slot 23;

[0055] When it is necessary to control the ammonia atomization range, and use a small range of ammonia atomization for precise denitrification;

[0056] The valve of the second infusion tube 4 can be opened, so that the ammonia water introduced into the inlet tube 1 will enter the second infusion tube 4, and then enter the first hollow box 18 through the second infusion tube 4, so that the impeller 29 in the first hollow box 18 rotates, and the impeller 29 drives the first drive shaft 16 to rotate, and the rotation of the first drive shaft 16 drives the first gear 17 to rotate, and the rotation of the first gear 17 drives the first rotating ring 19 to rotate through the latch 15. With the rotation of the first rotating ring 19, the first ventilation groove 21 on the first rotating ring 19 will be connected with the second ventilation groove 24 on the second rotating ring 25. In this way, the gas introduced into the ventilation cover 2 will be discharged along the gap between the fixed column 6 and the ventilation cover 2 through the first ventilation groove 21 and the second ventilation groove 24, and then discharged along the outer wall of the mounting cover 5 to form a gas wall, which can be used to limit the range of ammonia water atomization;

[0057] By pulling the liquid inlet pipe 1, the liquid inlet pipe 1 drives the blocking block 14 to move. When the top of the blocking block 14 contacts the threaded tube 8, the first air inlet groove 7 and the second air inlet groove 12 are blocked, so that the gas can only be discharged from the installation cover 5 to form an air wall. When the bottom of the blocking block 14 contacts the threaded tube 8, the second air inlet groove 12 is opened, so that the gas entering will extend along the inner and outer side walls of the installation cover 5 to form an air wall, further narrowing the range;

[0058] When the blocking block 14 blocks only the second air inlet groove 12, the gas is discharged from the mounting cover 5 to form an air wall, and is discharged from the opening of the threaded pipe 8 to form a smaller air wall range.

[0059] Embodiment 3:

[0060] like Figure 3-11As shown, in the case where other parts are the same as those in Example 1, the difference between this embodiment and Example 1 is that the impact atomization mechanism includes a fixed box 30, a rotating member 50 is fixedly connected inside the fixed box 30, a first rotating rod 36 is rotatably connected to the rotating member 50, a third gear 43 is fixedly connected to the first rotating rod 36, a connecting plate 51 is fixedly connected to the first rotating rod 36, a second auxiliary ring 42 is fixedly connected to the connecting plate 51, a second rotating disk 41 is rollingly connected to the second auxiliary ring 42, a second rotating disk 41 is fixedly connected to the second rotating rod 37, a second gear 40 is fixedly connected to the second rotating rod 37, and the second gear 40 is meshed with the third gear 43 The second rotating rod 37 is fixedly connected with the first rotating disk 38, a first auxiliary ring 39 is arranged above the first rotating disk 38, the first auxiliary ring 39 is fixedly connected with the fixed box 30, the first auxiliary ring 39 is rotatably connected with the first rotating disk 38, the bottom end of the second rotating rod 37 is rotatably connected with a rotating sleeve 47, the rotating sleeve 47 is fixedly connected with a connecting seat 44, the bottom of the connecting seat 44 is fixedly connected with a first pulley 45, the bottom of the first pulley 45 is fixedly connected with a rotating column 46, the rotating column 46 is rotatably connected with the fixed box 30, the first rotating rod 36 is fixedly connected with a second pulley 49, the first pulley 45 and the second pulley 49 are connected by a connecting belt 48;

[0061] The second rotating rod 37 has an impact plate 32 fixedly connected to the top thereof, and a plurality of protrusions 31 fixedly connected to the top of the impact plate 32, wherein the plurality of protrusions 31 have different shapes;

[0062] A second hollow box 34 is fixedly connected to the bottom of the fixed box 30, a second driving shaft is rotatably connected to the second hollow box 34, the second driving shaft is fixedly connected to the rotating column 46, an impeller 29 is arranged inside the second hollow box 34, the impeller 29 is fixedly connected to the second driving shaft, a third infusion tube 35 is fixedly connected to one end of the second hollow box 34, the third infusion tube 35 is connected to the first infusion tube 3, and a fourth infusion tube 33 is fixedly connected to the other end of the second hollow box 34;

[0063] When diffuse denitration is required, the valve on the second water delivery pipe can be closed, and the valve on the first liquid delivery pipe 3 can be opened, so that the ammonia water in the liquid inlet pipe 1 will enter the second hollow box 34 through the first liquid delivery pipe 3, so that the impeller 29 in the second hollow box 34 rotates, and the rotation of the impeller 29 drives the second drive shaft to rotate, and the rotation of the second drive shaft drives the rotating column 46 to rotate, and the rotating column 46 drives the second pulley 49 to rotate, and the second pulley 49 drives the connecting seat 44 to rotate, and the connecting seat 44 drives the rotating sleeve 47 to rotate, and the rotating sleeve 47 drives the second rotating rod 37 to rotate, and the second rotating rod 37 drives the first rotating disk 38 and the second rotating disk 41 to rotate, and the first rotating disk 38 rotates on the second auxiliary ring 42, and the second rotating disk 41 rotates on the second auxiliary ring 42, and the second rotating rod 37 also drives the impact disk 32 to rotate;

[0064] The high-pressure ammonia water sprayed from the liquid inlet pipe 1 will directly hit the impact plate 32, and be atomized by the impact, and the impact plate 32 is constantly tilted and rotated, so that the ammonia water atomized by the impact will drift along the inclined surface of the impact plate 32, thereby effectively changing the spraying path of the atomized ammonia water, so that it can spread over a wider range;

[0065] The impact plate 32 is provided with a plurality of bumps 31 of different shapes. When the ammonia water hits the bumps 31, the bumps 31 have different shapes and different contact surfaces with the ammonia water. Different surfaces reflect the ammonia water in different directions, which can further change the spraying path of the ammonia water and make it diffuse better.

[0066] The rotation of the second pulley 49 will also drive the first pulley 45 to rotate through the connecting belt 48, the first pulley 45 will drive the first rotating rod 36 to rotate, the first rotating rod 36 will drive the third gear 43 to rotate, the third gear 43 will drive the second gear 40 to rotate, the second gear 40 will drive the second rotating rod 37 to rotate, the rotation of the second rotating rod 37 will drive the impact disk 32 to rotate, the impact disk 32 will rotate, the rotating impact disk 32 can further throw away the ammonia water that has been atomized by impact, so that its diffusion range is larger.

[0067] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for reducing ammonia consumption and ammonia escape in SNCR denitration of cement kilns, characterized by: The following steps are involved: S1: Accurately select the installation position of the spray gun. According to the preliminary test results and the analysis of the on-site conditions, the final installation position of the spray gun is determined through CFD flow field simulation and further detection and analysis of the furnace atmosphere. By optimizing the position of the spray gun, the SNCR can be operated under the optimal temperature and atmosphere conditions, which can greatly improve the denitrification efficiency of the SNCR. In the later stage, special computer simulation and detection analysis will be provided for individual projects; S2: A new SNCR secondary precision distribution system is added, including a control system and five flow distribution systems, to achieve precise control of the flow of three-layer spray guns at the outlet of the decomposition furnace gooseneck tube, the C5 straight tube part, and the outlet of the C5 tube, and automatic adjustment of the flow distribution ratio of each set. The outlet of the decomposition furnace gooseneck tube is equipped with 8 spray guns, the straight section of the C5A / B tube is equipped with 6 spray guns, and the outlet of the C5A / B tube is equipped with 4 spray guns, a total of 28 spray guns; S3: Lay three ammonia water delivery pipelines to deliver ammonia water from the distribution cabinet to the gooseneck outlet of the decomposition furnace, the C5 straight tube, and the C5 outlet flue injection layer; S4: The whole system consists of 5 modules and 4 control cabinets, among which the decomposition furnace gooseneck outlet module is provided with a control cabinet 1, the C5A straight section module is provided with a control cabinet 2, the C5B straight section module is provided with a control cabinet 3, and the C5A outlet and C5B outlet modules share a control cabinet 4. Each module can be automatically controlled separately, and the frequency of the regulating valve and pump can be automatically controlled through temperature and atmosphere; S5: Add a flow rate regulating device for each group of spray guns. Through computer simulation and on-site test verification, it is found that the NOx distribution in the cross section of the decomposition furnace is very uneven. The area with high NOx concentration needs to spray more ammonia water, and vice versa. This requires that the flow rate of each group of spray guns can be adjusted. Reasonable adjustment of the flow rate of each gun can improve the utilization rate of ammonia water and the denitrification efficiency. S7: The opening position of the spray gun is located according to the simulation results; S8: Add an intelligent flue gas denitrification automatic control system to realize autonomous and stable operation of the denitrification system. The flow rate of each module spray gun can be independently and automatically distributed according to temperature changes. The system is developed based on the PID++ intelligent control system platform. The core of the control system is the neural network model. Many related variables are introduced into the model, such as the amount of ammonia sprayed by the decomposition furnace, secondary air temperature, NOx content at the outlet of the decomposition furnace / first-stage barrel, O2 content at the outlet of the decomposition furnace / first-stage barrel, and coal feeding amount of the decomposition furnace. The model prediction is used to eliminate the influence caused by long time lag.

2. A spray gun for reducing ammonia consumption and ammonia escape in SNCR denitration of cement kiln according to claim 1, comprising a vent hood (2), characterized in that: The ventilation cover (2) is fixedly connected to a fixing column (6), the fixing column (6) is slidably connected to a liquid inlet pipe (1), the fixing column (6) is threadedly connected to a nozzle, the nozzle is fixedly connected to a mounting cover (5), the mounting cover (5) is fixedly connected to a first liquid infusion pipe (3), the first liquid infusion pipe (3) is connected to the liquid inlet pipe (1), the bottom of the first liquid infusion pipe (3) is fixedly connected to an impact atomization mechanism, the right side of the liquid infusion pipe (1) is fixedly connected to a second liquid infusion pipe (4), the second liquid infusion pipe (4) is fixedly connected to a ventilation mechanism, and the ventilation mechanism is connected to the liquid inlet pipe (1) through the second liquid infusion pipe (4).

3. The spray gun according to claim 2, characterized in that: The nozzle comprises a threaded tube (8), the threaded tube (8) is threadedly connected to a fixing column (6), the threaded tube (8) is fixedly connected to a mounting cover (5), a slide groove (10) is provided on the threaded tube (8), a blocking block (14) is slidably connected inside the slide groove (10), the blocking block (14) is fixedly connected to a liquid inlet pipe (1), a second air inlet groove (12) is provided inside the threaded tube (8) and the mounting cover (5), a third air inlet groove (13) is provided inside the blocking block (14), and a first air inlet groove (7) is provided inside the fixing column (6).

4. The spray gun according to claim 2, characterized in that: Valves are installed on both the first infusion tube (3) and the second infusion tube (4); the portions of the first infusion tube (3) and the second infusion tube (4) located above the fixed column (6) are hoses; and the portions of the first infusion tube (3) and the second infusion tube (4) located on the left and right sides of the ventilation hood (2) are fixedly connected to the ventilation hood (2).

5. The spray gun according to claim 1, characterized in that: The ventilation mechanism comprises a first rotating ring (19), the first rotating ring (19) is rotatably connected to the fixed column (6), a plurality of positioning components are fixedly connected to the first rotating ring (19), a first ventilation groove (21) is provided on the first rotating ring (19), a plurality of latching teeth (15) are fixedly connected to the first rotating ring (19), a first gear (17) is meshed on the latching teeth (15), a first driving shaft (16) is fixedly connected to the first gear (17), a first hollow box (18) is rotatably connected to the first driving shaft (16), and the first hollow box (18) is connected to the ventilation The first hollow box (18) is fixedly connected to the ventilation cover (2); an impeller (29) is arranged inside the first hollow box (18); the impeller (29) is fixedly connected to the first drive shaft (16); the first hollow box (18) is fixedly connected to the second infusion tube (4); a second rotating ring (25) is arranged below the first rotating ring (19); a plurality of slots (23) are provided on the second rotating ring (25); the second rotating ring (25) is fixedly connected to the ventilation cover (2) and the fixing column (6); a second ventilation slot (24) is provided through the second rotating ring (25); and a slot is provided on the second rotating ring (25).

6. The spray gun according to claim 5, characterized in that: The positioning assembly comprises a positioning tube (20), the positioning tube (20) is fixedly connected to the first rotating ring (19), a slide plate (27) is slidably connected inside the positioning tube (20), the top of the slide plate (27) is connected to the positioning tube (20) via a spring (26), and an insert block (28) is fixedly connected to the bottom of the slide plate (27), and the insert block (28) is plugged into the slot (23).

7. The spray gun according to claim 2, characterized in that: The impact atomization mechanism comprises a fixed box (30), a rotating member (50) is fixedly connected inside the fixed box (30), a first rotating rod (36) is rotatably connected to the rotating member (50), a third gear (43) is fixedly connected to the first rotating rod (36), a connecting plate (51) is fixedly connected to the first rotating rod (36), a second auxiliary ring (42) is fixedly connected to the connecting plate (51), a second rotating disk (41) is rollingly connected to the second auxiliary ring (42), a second rotating rod (37) is fixedly connected to the second rotating disk (41), a second gear (40) is fixedly connected to the second rotating rod (37), the second gear (40) is meshed with the third gear (43), and the first rotating disk (41) is fixedly connected to the second rotating rod (37). 38), a first auxiliary ring (39) is arranged above the first rotating disk (38), the first auxiliary ring (39) is fixedly connected to the fixed box (30), the first auxiliary ring (39) is rotatably connected to the first rotating disk (38), the bottom end of the second rotating rod (37) is rotatably connected to a rotating sleeve (47), the rotating sleeve (47) is fixedly connected to a connecting seat (44), the bottom of the connecting seat (44) is fixedly connected to a first pulley (45), the bottom of the first pulley (45) is fixedly connected to a rotating column (46), the rotating column (46) is rotatably connected to the fixed box (30), the first rotating rod (36) is fixedly connected to a second pulley (49), the first pulley (45) and the second pulley (49) are connected by a connecting belt (48).

8. The spray gun according to claim 7, characterized in that: The top of the second rotating rod (37) is fixedly connected to an impact plate (32), and the top of the impact plate (32) is fixedly connected to a plurality of protrusions (31), wherein the plurality of protrusions (31) have different shapes.

9. The spray gun according to claim 7, characterized in that: A second hollow box (34) is fixedly connected to the bottom of the fixed box (30); a second driving shaft is rotatably connected to the second hollow box (34); the second driving shaft is fixedly connected to a rotating column (46); an impeller (29) is arranged inside the second hollow box (34); the impeller (29) is fixedly connected to the second driving shaft; a third infusion tube (35) is fixedly connected to one end of the second hollow box (34); the third infusion tube (35) is communicated with the first infusion tube (3); and a fourth infusion tube (33) is fixedly connected to the other end of the second hollow box (34).

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