A cement kiln flue gas SCR denitrification device

Abstract

The present invention discloses a cement kiln flue gas SCR denitrification device, comprising a plurality of ammonia spraying pipes installed at the air inlet end of a smoke-ammonia mixing pipe, wherein the plurality of ammonia spraying pipes are evenly distributed around the axis of the smoke-ammonia mixing pipe, and the ammonia spraying pipes located in the smoke-ammonia mixing pipe extend toward the side wall of the smoke-ammonia mixing pipe, and the nozzles at the ends of the ammonia spraying pipes are arranged horizontally; each ammonia spraying pipe is rotatably and sealedly connected to the end of the air inlet end of the smoke-ammonia mixing pipe, and an external gear is installed on the outer peripheral body of the ammonia spraying pipe located outside the smoke-ammonia mixing pipe, a reciprocating motor is installed at the axis of the outer end of the smoke-ammonia mixing pipe, and an executing end of the reciprocating motor is installed with a driving gear meshing with the external gear; the reciprocating motor drives the plurality of ammonia spraying pipes to rotate, so that ammonia can be in more complete contact with the smoke, thereby promoting the uniformity of the smoke gas reaction in the pipe and improving the denitrification efficiency.

Description

Technical Field

[0001] The invention relates to a cement kiln flue gas SCR denitrification device, belonging to the technical field of flue gas denitrification. Background Art

[0002] SCR denitrification is selective catalytic reduction technology, which has been developing rapidly in recent years. Selectivity refers to the preferential conversion of NH3 to NO under the action of catalyst and in the presence of oxygen. X A reduction reaction occurs to produce nitrogen and water, but no oxidation reaction occurs with oxygen in the flue gas. In the absence of a catalyst, the above chemical reaction only occurs within a very narrow temperature range. When a catalyst is used, the reaction temperature can be controlled at 300-400°C, which is equivalent to the flue gas temperature between the boiler economizer and the air preheater. The above reaction is an exothermic reaction. X The concentration in the flue gas is low, so the increase in catalyst temperature caused by the reaction can be ignored.

[0003] During the denitration reaction, ammonia is usually sprayed into the reaction vessel to react with the flue gas. However, in existing SCR denitration devices, the ammonia injection point is fixed. During the reaction, the flue gas near the injection point easily reacts first, while the flue gas far from the injection point reacts slowly or does not react at all. This causes uneven flue gas reaction inside the SCR denitration device and low denitration reaction efficiency. In addition, the mobile ammonia injection point has poor air tightness and poor practicality. Summary of the Invention

[0004] The purpose of the present invention is to provide a cement kiln flue gas SCR denitrification device, which drives multiple ammonia injection pipes to rotate through a reciprocating motor so that ammonia can be more fully in contact with the flue gas, promotes the uniformity of the flue gas reaction in the pipe, and improves the denitrification efficiency.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A cement kiln flue gas SCR denitrification device comprises a plurality of ammonia injection pipes installed at the air inlet end of a flue gas and ammonia mixing pipe, wherein the plurality of ammonia injection pipes are evenly distributed around the axis of the flue gas and ammonia mixing pipe, and the ammonia injection pipes located within the flue gas and ammonia mixing pipe extend toward the side wall of the flue gas and ammonia mixing pipe, and the nozzles at the ends of the ammonia injection pipes are arranged horizontally;

[0007] Each ammonia injection pipe is rotatably and sealingly connected to the air inlet end of the tobacco and ammonia mixing pipe, and an external gear is installed on the outer periphery of the ammonia injection pipe located outside the tobacco and ammonia mixing pipe. A reciprocating motor is installed at the axis of the outer end of the tobacco and ammonia mixing pipe, and the actuator end of the reciprocating motor is installed with a driving gear that meshes with the external gear.

[0008] The ammonia injection pipe is driven to rotate by a reciprocating motor to fully mix the flue gas and ammonia.

[0009] Preferably, the effective radius of the nozzle of each ammonia injection pipe is greater than the distance between the axis of the nozzle and the axis of the smoke-ammonia mixing pipe.

[0010] Preferably, a support assembly for stabilizing the ammonia injection pipeline is installed on the inner side of the air inlet end of the smoke and ammonia mixing pipeline.

[0011] Preferably, the support assembly includes a fixed plate, and the fixed plate is connected to the inner side wall of the air inlet end of the smoke-ammonia mixing pipe through a plurality of connecting rods;

[0012] A plurality of ammonia injection pipelines penetrate the fixed disk and are connected to the fixed disk for relative rotation.

[0013] Preferably, the number of the ammonia injection pipelines is 3-5.

[0014] Preferably, a mixer for improving the degree of mixing of flue gas and ammonia is also installed in the flue gas and ammonia mixing pipe located at the rear side of the ammonia injection pipe.

[0015] Preferably, the mixer comprises a front mixer and a rear mixer, and the front mixer and the rear mixer each comprise an outer ring body and a cross rod with a conical structure provided in the outer ring body;

[0016] An upper fan-shaped guide plate and a lower fan-shaped guide plate are provided between the cross rod bodies of the front mixer and the rear mixer; and the upper fan-shaped guide plate and the lower fan-shaped guide plate on the same mixer are located on different sides of the vertical cross rod; and the upper fan-shaped guide plates on the two mixers are located on different sides of the smoke and ammonia mixing pipe, and the lower fan-shaped guide plates are also located on different sides of the smoke and ammonia mixing pipe.

[0017] Preferably, the areas of the upper fan-shaped guide plate and the lower fan-shaped guide plate on the front mixer are smaller than the areas of the upper fan-shaped guide plate and the lower fan-shaped guide plate on the rear mixer.

[0018] Preferably, an arc-shaped chute is provided in the front mixer side smoke and ammonia mixing pipe and the rear mixer side smoke and ammonia mixing pipe respectively, and a slider is provided on the outer ring body to be embedded in the corresponding side arc-shaped chute;

[0019] A driving assembly is provided in the smoke-ammonia mixing pipeline, which drives the front mixer and the rear mixer to rotate along corresponding arc-shaped slide grooves and move closer to or away from each other.

[0020] Preferably, the drive assembly includes a bidirectional screw rod radially arranged in the tobacco-ammonia mixing pipe, one end of the bidirectional screw rod being connected to the inner wall of the tobacco-ammonia mixing pipe for relative rotation, and the other end of the bidirectional screw rod extending outside the tobacco-ammonia mixing pipe and also being connected to the tobacco-ammonia mixing pipe in a sealed and relative rotation manner;

[0021] A servo motor connected to the outer end of a bidirectional screw rod and capable of driving the bidirectional screw rod to rotate is installed on the tobacco and ammonia mixing pipe;

[0022] A rotating rod is rotatably provided at the center of the cross rod of the front mixer and the rear mixer, and a limit plate is provided on the rotating rod located on both sides of the cross rod;

[0023] Corresponding connecting plates are provided on the upper and lower sides of the side wall of the rotating rod close to one end of the bidirectional screw and on the side walls of the two wire seats of the bidirectional screw close to the corresponding side mixer, and a transmission rod is hinged between the corresponding connecting plates;

[0024] The servo motor drives the bidirectional screw to rotate in the forward and reverse directions to drive the two screw seats to move closer to or away from each other, and then the transmission rod pulls or pushes the front mixer and the rear mixer to move closer to or away from each other. Under the action of the arc-shaped slide, the front mixer and the rear mixer can rotate relative to each other when they move closer to or away from each other, thereby realizing dynamic mixing of ammonia and flue gas.

[0025] The beneficial effects of the present invention are:

[0026] 1. The reciprocating motor drives multiple ammonia injection pipes to rotate, so that the ammonia sprayed from the nozzle at the end of the ammonia injection pipe can fully contact the flue gas, thereby promoting the uniformity of the reaction between ammonia and flue gas in the pipe, and improving the denitrification efficiency and denitrification effect;

[0027] 2. The servo motor can pull or push the front mixer and the rear mixer closer to or away from each other, and under the action of the arc chute, the front mixer and the rear mixer can rotate relative to each other when they are closer to or away from each other. When the mixer rotates, the position of the guide plate will change relatively, thereby achieving dynamic mixing of ammonia and flue gas, and then promoting the reaction between ammonia and flue gas, thereby improving the denitrification efficiency and denitrification effect.

[0028] 3. The fan-shaped guide plates on the front mixer and the fan-shaped guide plates on the rear mixer are completely staggered, which can fully mix the flue gas and ammonia, thereby improving the denitrification efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a side sectional view of the denitrification device;

[0030] Figure 2 This is a schematic diagram of the main view of the ammonia injection pipeline;

[0031] Figure 3 It is a side cross-sectional view of the cross rod and the outer ring;

[0032] Figure 4 This is a schematic diagram of the front-end mixer;

[0033] Figure 5This is a schematic diagram of the main view of the back-end mixer;

[0034] The main reference numerals in the figures have the following meanings:

[0035] 1. Smoke and ammonia mixing pipe, 2. Ammonia spray pipe, 3. Fixed plate, 4. Connecting rod, 5. External gear, 6. Reciprocating motor, 7. Driving gear, 8. Front mixer, 9. Rear mixer, 10. Outer ring, 11. Cross rod, 12. Upper fan-shaped guide plate, 13. Lower fan-shaped guide plate, 14. Arc slide, 15. Slider, 16. Bidirectional screw, 17. Servo motor, 18. Rotating rod, 19. Limit plate, 20. Connecting plate, 21. Transmission rod. DETAILED DESCRIPTION

[0036] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0037] like Figure 1-5 As shown: This embodiment is a cement kiln flue gas SCR denitrification device, including three ammonia spray pipes 2 installed at the air inlet end of the smoke-ammonia mixing pipe 1, the multiple ammonia spray pipes 2 are evenly distributed around the axis of the smoke-ammonia mixing pipe 1, and the ammonia spray pipes 2 located in the smoke-ammonia mixing pipe 1 extend toward the side wall of the smoke-ammonia mixing pipe 1, and the nozzle at the end of the ammonia spray pipe 2 is horizontally arranged.

[0038] Each ammonia injection pipe 2 is rotatably and hermetically connected to the air inlet end of the flue gas-ammonia mixing pipe 1. To improve stability, a support assembly for stabilizing the ammonia injection pipe 2 is installed on the inner side of the air inlet end of the flue gas-ammonia mixing pipe 1. The support assembly includes a fixed disk 3, which is connected to the inner side wall of the air inlet end of the flue gas-ammonia mixing pipe 1 via multiple connecting rods 4. The three ammonia injection pipes 2 pass through the fixed disk 3 and are rotatably connected to the fixed disk 3. At the same time, to ensure that ammonia can be fully mixed with the flue gas, the effective radius of the nozzle of each ammonia injection pipe 2 is greater than the distance between the nozzle axis and the axis of the flue gas-ammonia mixing pipe 1.

[0039] An external gear 5 is installed on the outer periphery of the ammonia injection pipeline 2 located outside the smoke-ammonia mixing pipeline 1, and a reciprocating motor 6 is installed at the axis center of the outer end of the smoke-ammonia mixing pipeline 1. The execution end of the reciprocating motor 6 is installed with a driving gear 7 that meshes with the external gear 5; the reciprocating motor 6 drives the ammonia injection pipeline 2 to rotate so that the smoke and ammonia are fully mixed.

[0040] like Figure 1-2As shown, after the flue gas enters the smoke-ammonia mixing pipe 1 through the lower pipe, the reciprocating motor 6 is started. The reciprocating motor 6 drives the nozzle at the end of the ammonia injection pipe 2 to rotate relative to the axis of the smoke-ammonia mixing pipe 1 through the transmission of the driving gear 7 and the external gear 5, so that the ammonia gas sprayed through the ammonia injection pipe 2 can fully act on the flue gas in the smoke-ammonia mixing pipe 1; the commonly used control method is: first rotate forward 60-80°, then rotate reverse 120-160°, and then rotate forward 120°-160°, and repeat the cycle.

[0041] In order to improve the mixing degree of flue gas and ammonia, so as to achieve the goal of increasing efficiency and speed, a mixer is installed in the flue gas and ammonia mixing pipe 1 located at the rear side of the ammonia injection pipe 2. Figure 3-5 As shown, the mixer includes a front mixer 8 and a rear mixer 9, each of which includes an outer ring 10 and a conical cross rod 11 disposed within the outer ring 10. An upper fan-shaped guide plate 12 and a lower fan-shaped guide plate 13 are disposed between the cross rods 11 of the front mixer 8 and the rear mixer 9.

[0042] The upper and lower fan-shaped guide plates 12, 13 on the same mixer are located on different sides of the vertical crossbar 11; the upper and lower fan-shaped guide plates 12, 13 on the two mixers are located on different sides of the flue gas and ammonia mixing pipe 1, and the lower fan-shaped guide plates 13 are also located on different sides of the flue gas and ammonia mixing pipe 1. Furthermore, the areas of the upper and lower fan-shaped guide plates 12, 13 on the front mixer 8 are smaller than those on the rear mixer 9. The fan-shaped guide plates on the front mixer 8 and the rear mixer 9 are completely staggered, ensuring thorough mixing of the flue gas and ammonia, thereby improving denitrification efficiency.

[0043] In order to further improve the mixing effect of ammonia and flue gas, arc-shaped slide grooves 14 are respectively opened in the smoke-ammonia mixing pipe 1 on the front mixer 8 side and the smoke-ammonia mixing pipe 1 on the rear mixer 9 side, and a slider 15 embedded in the corresponding side arc-shaped slide groove 14 is provided on the outer ring body 10; and a driving component is provided in the smoke-ammonia mixing pipe 1 to drive the front mixer 8 and the rear mixer 9 to rotate along the corresponding arc-shaped slide groove 14 and approach or move away from each other.

[0044] The driving assembly includes a bidirectional screw rod 16 radially arranged in the tobacco and ammonia mixing pipe 1, one end of the bidirectional screw rod 16 is connected to the inner wall of the tobacco and ammonia mixing pipe 1 for relative rotation, and the other end extends to the outside of the tobacco and ammonia mixing pipe 1 and is also sealed and connected to the tobacco and ammonia mixing pipe 1 for relative rotation; a servo motor 17 connected to the outer end of the bidirectional screw rod 16 and capable of driving the bidirectional screw rod 16 to rotate is installed on the tobacco and ammonia mixing pipe 1; a rotating rod 18 is rotatably arranged at the center of the cross rod 11 of the front mixer 8 and the rear mixer 9, and a limiting plate 19 is provided on the rotating rod 18 on both sides of the cross rod 11; corresponding connecting plates 20 are provided on the upper and lower side walls of one end of the rotating rod 18 close to the bidirectional screw rod 16 and on the side walls of the two wire seats of the bidirectional screw rod 16 close to the corresponding side mixer, and a transmission rod 21 is hinged between the corresponding connecting plates 20.

[0045] In actual application, the bidirectional screw 16 is driven to rotate forward and reverse by the servo motor 17 to drive the two wire seats on the screw to move closer to or away from each other, and then the front end mixer 8 and the rear end mixer 9 can be pulled or pushed closer to or away from each other through the transmission rod 21, and under the guidance of the arc-shaped slide groove 14, the front end mixer 8 and the rear end mixer 9 will rotate relative to each other when they move closer to or away from each other; when the mixer rotates, the position of the guide plate will change relatively, so that dynamic mixing of ammonia and flue gas can be achieved, the reaction of ammonia and flue gas can be promoted, and the denitrification efficiency and denitrification effect can be improved.

[0046] The above is only a preferred embodiment of the patent of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the patent of the present invention. These improvements and modifications should also be regarded as the scope of protection of the patent of the present invention.

Claims

1. A cement kiln flue gas SCR denitrification device, characterized in that: The ammonia spraying pipe comprises a plurality of ammonia spraying pipes installed at the air inlet end of the tobacco smoke and ammonia mixing pipe, the plurality of ammonia spraying pipes are evenly distributed around the axis of the tobacco smoke and ammonia mixing pipe, and the ammonia spraying pipes located in the tobacco smoke and ammonia mixing pipe extend toward the side wall of the tobacco smoke and ammonia mixing pipe, and the nozzles at the ends of the ammonia spraying pipes are arranged horizontally; Each ammonia injection pipe is rotatably and sealingly connected to the air inlet end of the tobacco and ammonia mixing pipe, and an external gear is installed on the outer periphery of the ammonia injection pipe located outside the tobacco and ammonia mixing pipe. A reciprocating motor is installed at the axis of the outer end of the tobacco and ammonia mixing pipe, and a driving gear that meshes with the external gear is installed at the actuator end of the reciprocating motor; The reciprocating motor drives the ammonia injection pipe to rotate so that the flue gas and ammonia are fully mixed; A mixer for improving the mixing degree of flue gas and ammonia is also installed in the flue gas and ammonia mixing pipe located at the rear side of the ammonia injection pipe. The mixer includes a front mixer and a rear mixer. Both the front mixer and the rear mixer include an outer ring body and a cross rod with a conical structure arranged in the outer ring body. An upper fan-shaped guide plate and a lower fan-shaped guide plate are provided between the cross rods of the front mixer and the rear mixer; the upper fan-shaped guide plate and the lower fan-shaped guide plate on the same mixer are located on different sides of the vertical cross rod; the upper fan-shaped guide plates on the two mixers are located on different sides of the tobacco and ammonia mixing pipe, and the lower fan-shaped guide plates are also located on different sides of the tobacco and ammonia mixing pipe; Arc-shaped chutes are respectively provided in the smoke-ammonia mixing pipe on the front mixer side and the smoke-ammonia mixing pipe on the rear mixer side, and sliders embedded in the corresponding side arc-shaped chutes are provided on the outer ring body; A drive assembly is provided in the tobacco-ammonia mixing pipe to drive the front-end mixer and the rear-end mixer to rotate along corresponding arc-shaped slideways and move closer to or away from each other. The drive assembly includes a bidirectional screw rod radially arranged in the tobacco-ammonia mixing pipe, one end of the bidirectional screw rod is connected to the inner wall of the tobacco-ammonia mixing pipe for relative rotation, and the other end extends outside the tobacco-ammonia mixing pipe and is also connected to the tobacco-ammonia mixing pipe in a sealed and relatively rotational manner. A servo motor connected to the outer end of a bidirectional screw rod and capable of driving the bidirectional screw rod to rotate is installed on the tobacco and ammonia mixing pipe; A rotating rod is rotatably provided at the center of the cross rod of the front mixer and the rear mixer, and a limit plate is provided on the rotating rod located on both sides of the cross rod; Corresponding connecting plates are provided on the upper and lower side walls of the rotating rod close to one end of the bidirectional screw and on the side walls of the two wire seats of the bidirectional screw close to the corresponding side mixer, and a transmission rod is hinged between the corresponding connecting plates.

2. The cement kiln flue gas SCR denitrification device according to claim 1, characterized in that: The effective radius of each nozzle of the ammonia spraying pipeline is greater than the distance between the axis of the nozzle and the axis of the smoke-ammonia mixing pipeline.

3. The cement kiln flue gas SCR denitrification device according to claim 1, characterized in that: A support assembly for stabilizing the ammonia injection pipeline is installed on the inner side of the air inlet end of the smoke and ammonia mixing pipeline.

4. The cement kiln flue gas SCR denitrification device according to claim 3, characterized in that: The support assembly includes a fixed plate, which is connected to the inner side wall of the air inlet end of the smoke and ammonia mixing pipe through a plurality of connecting rods; A plurality of ammonia injection pipelines penetrate the fixed disk and are connected to the fixed disk for relative rotation.

5. The cement kiln flue gas SCR denitrification device according to claim 1, characterized in that: The number of the ammonia injection pipelines is 3-5.

6. The cement kiln flue gas SCR denitrification device according to claim 1, characterized in that: The areas of the upper fan-shaped guide plate and the lower fan-shaped guide plate on the front mixer are both smaller than those of the upper fan-shaped guide plate and the lower fan-shaped guide plate on the rear mixer.

7. The cement kiln flue gas SCR denitrification device according to claim 1, characterized in that: The servo motor drives the bidirectional screw to rotate in the forward and reverse directions to drive the two screw seats to move closer to or away from each other, and then the transmission rod pulls or pushes the front mixer and the rear mixer to move closer to or away from each other. Under the action of the arc-shaped slide, the front mixer and the rear mixer can rotate relative to each other when they move closer to or away from each other, thereby realizing dynamic mixing of ammonia and flue gas.

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