Waste gas emission spray tower for steel mill denitration and use method of waste gas emission spray tower

Abstract

The invention relates to the technical field of spray towers, discloses an exhaust gas emission spray tower for steel mill denitration and a use method thereof, and aims to overcome the defect of insufficient reaction of absorption liquid and exhaust gas caused by high probability of airflow bias in the tower in the prior art. According to the invention, the arc-shaped fan blades which are reversely guided up and down are matched to form a turbulent flow area and a gas-liquid reciprocating mixing zone, so that the contact time of waste gas and atomized absorption liquid is prolonged, and the denitration reaction sufficiency is improved; by means of a cam-reciprocating cross plate structure linked with a central shaft, reciprocating knocking of the vibration rod on the annular pipe is achieved, and crystallization blockage of the atomization spray head is effectively reduced; by matching with the circulating box, the double filters and the PLC control system, the concentration of the absorption liquid and the rotating speed of the fan blades can be regulated and controlled in real time, the treatment stability is guaranteed, meanwhile, the equipment blockage risk and the fan energy consumption are reduced through the design of the dust removal filter and the demister, and the synergistic effect of efficient denitration, blockage prevention and consumption reduction is integrally achieved.

Description

Technical Field

[0001] This invention relates to the field of spray tower technology, and in particular to a waste gas emission spray tower for denitrification in steel plants and its usage method. Background Technology

[0002] A denitrification exhaust gas scrubbing tower is an environmental protection device used to treat industrial waste gases such as those from steel plants and power plants. Its core function is to remove nitrogen oxides (NOx) from the waste gases. x This reduces pollutant emissions and achieves efficient purification through the spray absorption principle, ensuring that exhaust gas meets emission standards.

[0003] Chinese Patent Publication No. CN115671996B discloses a waste gas purification device for denitrification in steel plants and its usage method. The device includes a spray tower body, a recovery box fixedly connected to the right side of the spray tower body, and three frames movably connected to the inner cavity of the spray tower body, arranged sequentially from top to bottom. A push plate is movably connected to the top of the recovery box. This invention solves the problem that because multiple filter plates are installed inside the spray tower, each filter plate needs to be removed individually during cleaning, resulting in a significant waste of time during disassembly and assembly, thus affecting the work efficiency of operators and reducing the amount of waste gas that can be treated.

[0004] Regarding the above-mentioned and existing related technologies, the inventors believe that the following defects exist:

[0005] This denitrification device utilizes a well-designed arrangement of multi-layer filter plates or specialized packing to create a core carrier for sufficient contact and reaction between the absorbent and the waste gas. However, during long-term operation, the filter plate surface is prone to blockage due to impurity deposition and reactant adhesion. This directly obstructs the flow of waste gas within the filter plate area, causing uneven gas transfer and transport. Consequently, the upward flow of air inside the tower becomes turbulent, and the airflow distribution in localized areas becomes unbalanced. Ultimately, this prevents the waste gas from achieving complete and sufficient contact and reaction with the absorbent in those areas. This insufficient contact directly weakens the overall efficiency and effectiveness of the denitrification reaction, adversely affecting the achievement of the final denitrification targets.

[0006] Therefore, we designed a waste gas emission spray tower for steel plant denitrification and its application method to solve the problems mentioned above. Summary of the Invention

[0007] The technical problem to be solved by this invention is that the existing technology is prone to airflow deviation in the tower, resulting in insufficient reaction between the absorbent liquid and the waste gas. To address this, we propose a waste gas emission spray tower for denitrification in steel plants and its usage method.

[0008] To achieve the above objectives, this application adopts the following technical solution: a waste gas emission spray tower for denitrification in steel plants and its usage method, comprising a spray tower body, a salt leg connected to the bottom end of the spray tower body, an exhaust pipe connected to the top end of the spray tower body, an air inlet pipe connected to one side of the spray tower body, an annular pipe fixed inside the spray tower body, a cross pipe connected to the inner side of the annular pipe, atomizing nozzles evenly arranged at the bottom of the annular pipe and the cross pipe, and a ring frame rotatably installed on the inner wall of the spray tower body above and below the annular pipe. Three fan blades are evenly fixed on the inner wall of the ring frame, and a central shaft is connected to the inner side of the same group of fan blades. The central shaft is located at the axis of the ring frame, and a second cone is fixed at the top end of the central shaft. Servo motors are installed on the side walls of the spray tower body at positions corresponding to the second bevel gear. One end of each servo motor is connected to a rotating shaft, and one end of each rotating shaft extends into the interior of the spray tower body and is connected to the first bevel gear. The first bevel gear meshes with the adjacent central shaft. A protective cover is fitted around the near end of the rotating shaft and the adjacent central shaft. The two sets of fan blades have opposite airflow directions: the lower fan blade guides airflow upwards, and the upper fan blade guides airflow downwards. The rotation speed of the upper fan blade is less than that of the lower fan blade. The air outlet of the air inlet pipe is located below the bottom fan blade. An airflow sensor monitors the airflow data of the exhaust pipe in real time and feeds it back to the PLC control system to adaptively adjust the speed of the servo motors.

[0009] Preferably, a demister is installed inside the spray tower body at the end near the exhaust pipe, and a dust filter is installed at the end of the air inlet pipe near the exhaust port.

[0010] Preferably, the cross-section of the fan blade is arc-shaped, the arc-shaped opening angle of the fan blade is 55°, and the interval opening angle between fan blades in the same group is 65°.

[0011] Preferably, a connecting rod is fixed on both inner sides of the annular tube, and a vibrating rod is fixed on the inner side of the bottom of the connecting rod. A reciprocating cross plate is connected between the two vibrating rods. A second guide hole is opened on the reciprocating cross plate. An eccentric shaft passes through the inside of the second guide hole. A cam is fixed at the bottom end of the eccentric shaft. A through shaft is fixed at the bottom axis of the cam. The bottom end of the through shaft passes through the protective cover and is coaxially connected with the central shaft below.

[0012] Preferably, the reciprocating cross plate has a first guide hole on both sides, and the bottom end of the vibrating rod passes through the first guide hole. The first guide hole and the second guide hole are vertically distributed.

[0013] Preferably, the length of the first guide hole is matched with the rotation diameter of the eccentric shaft.

[0014] Preferably, a circulation tank is provided on one side of the main body of the spray tower, and a circulation pump is installed at the top of the circulation tank. One end of the circulation pump is connected to the inside of the circulation tank through a liquid extraction pipe, and the other end of the circulation pump is connected to one side of the ring pipe through a liquid delivery pipe. The bottom of the circulation tank is connected to one side of the salt leg through a circulation pipe. A double filter is provided on the circulation pipe, and a replenishment pipe is connected to one side of the top of the circulation tank.

[0015] Preferably, a concentration sensor is installed on one side of the circulation tank, and the servo motor, circulation pump, concentration sensor and airflow sensor are all connected to the PLC control system.

[0016] The technical effects and advantages of this invention are as follows:

[0017] In this invention, to optimize the denitrification effect of waste gas, an innovative structural design is adopted to achieve multiple functions in synergy. The core lies in the arc-shaped fan blade assembly with upward and downward counter-current flow guidance. Through the counter-current flow guidance effect of the curved surface of the fan blades, the waste gas and the atomized absorbent liquid form a stable turbulent zone in the reaction chamber, while simultaneously constructing a gas-liquid reciprocating mixing zone. This significantly extends the contact path and reaction time between the two, allowing the denitrification chemical reaction to be more complete and thorough, and significantly improving the pollutant removal efficiency.

[0018] In terms of anti-clogging design, relying on the cam-reciprocating cross plate transmission structure linked to the central shaft, the vibrating rod is driven to reciprocate the annular liquid distribution pipe at high frequency. The vibration effect is used to destroy the formation conditions of crystallized deposits at the nozzle, effectively solving the industry pain point of easy crystallization and clogging of atomizing nozzles during long-term operation.

[0019] In addition, the system is equipped with a circulation tank, a two-stage precision filter, and a PLC intelligent control system, which can monitor and dynamically adjust the concentration of the absorbent and the fan blade rotation speed in real time to ensure that the treatment process is always under optimal conditions, guaranteeing the stability and consistency of the denitrification effect. At the same time, the dust filter pre-treatment removes particulate matter from the exhaust gas, and the demister separates liquid droplets entrained in the exhaust gas, which not only reduces the risk of clogging of subsequent equipment, but also reduces the operating resistance of the fan, achieving energy consumption optimization, and ultimately achieving multiple technical goals of efficient denitrification, anti-clogging, and energy saving. Attached Figure Description

[0020] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts:

[0021] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0022] Figure 2 This is a schematic diagram of the three-dimensional structure of the fan blade distribution of the present invention;

[0023] Figure 3This is a schematic diagram of the internal three-dimensional structure of the protective cover of the present invention;

[0024] Figure 4 This is a bottom-view three-dimensional structural diagram of the annular tube of the present invention;

[0025] Figure 5 This is a schematic diagram of the three-dimensional structure of the reciprocating cross plate of the present invention.

[0026] Explanation of reference numerals in the attached drawings: 1. Main body of the spray tower; 11. Salt leg; 12. Exhaust pipe; 13. Air inlet pipe; 2. Circulation box; 21. Circulation pump; 22. Liquid extraction pipe; 23. Liquid delivery pipe; 24. Liquid replenishment pipe; 25. Circulation pipe; 26. Dual filter; 3. Servo motor; 31. Rotating shaft; 32. First bevel gear; 4. Ring frame; 41. Fan blade; 42. Central shaft; 43. Second bevel gear; 5. Protective cover; 51. Through shaft; 52. Cam; 53. Eccentric shaft; 6. Annular pipe; 61. Cross pipe; 62. Atomizing nozzle; 63. Connecting rod; 64. Vibrating rod; 65. Reciprocating cross plate; 651. First guide hole; 652. Second guide hole. Detailed Implementation

[0027] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0028] Reference Figures 1-4As shown, the present invention provides a technical solution: a waste gas emission spray tower for denitrification in steel plants and its usage method, comprising a spray tower body 1, a salt leg 11 connected to the bottom end of the spray tower body 1, an exhaust pipe 12 connected to the top end of the spray tower body 1, an air inlet pipe 13 connected to one side of the spray tower body 1, an annular pipe 6 fixed inside the spray tower body 1, a cross pipe 61 connected to the inner side of the annular pipe 6, atomizing nozzles 62 evenly arranged at the bottom of the annular pipe 6 and the cross pipe 61, and a ring frame 4 rotatably installed on the inner wall of the spray tower body 1 above and below the annular pipe 6. The ring frame 4 is located in an annular groove opened in the inner wall of the spray tower body 1, and three fan blades 41 are evenly fixed on the inner wall of the ring frame 4. The inner side of the same group of fan blades 41 is connected to a central shaft 42, which is located in the ring frame. The top of the central shaft 42 is fixed with a second bevel gear 43. A servo motor 3 is installed on the side wall of the spray tower body 1 at the position corresponding to the second bevel gear 43. One end of the servo motor 3 is connected to a rotating shaft 31. One end of the rotating shaft 31 extends into the interior of the spray tower body 1 and is connected to a first bevel gear 32. The first bevel gear 32 and the adjacent central shaft 42 mesh with each other. The near ends of the rotating shaft 31 and the adjacent central shaft 42 are fitted with a protective cover 5. The two sets of fan blades 41 have opposite guiding directions. The fan blade 41 located below guides upward, and the fan blade 41 located above guides downward. The air outlet of the air inlet pipe 13 is located below the bottom fan blade 41. The rotation speed of the fan blade 41 located above is less than that of the fan blade 41 located below. An airflow sensor is installed at the air inlet of the exhaust pipe 12.

[0029] By utilizing the cooperation of the upper and lower sets of fan blades 41, the lower fan blade 41 guides the initial inlet exhaust gas into the spray tower, forcing the exhaust gas to flow evenly within the spray tower body 1. This simultaneously slows down the rapid dust settling of droplets in the exhaust gas and atomized liquid in the absorbent, thereby improving the full contact reaction between the exhaust gas and the absorbent. The upper fan blade 41 works in conjunction with the lower fan blade 41 to form a turbulent zone between them, dispersing the rising liquid mist to further improve the full contact between the mist and the absorbent. At the same time, this reverse rotational force causes the gas and liquid phases to form a reciprocating mixing zone in the middle of the spray tower body 1, extending the contact time. Furthermore, the slight upward airflow formed inside the spray tower body 1 reduces the wind pressure load on the fan connected to the exhaust pipe 12, which helps to reduce energy consumption.

[0030] Reference Figure 1 As shown in this embodiment: a demister is installed inside the spray tower body 1 at one end near the exhaust pipe 12, and a dust filter is installed at one end of the air inlet pipe 13 near the exhaust port.

[0031] The demister is used to further reduce the liquid droplets in the gas and improve the exhaust accuracy of the exhaust pipe 12. At the same time, the dust filter is used to further reduce the content of dust and other particulate impurities in the gas that enters the spray tower body 1 directly, thereby reducing dust collection and blockage inside the spray tower body 1.

[0032] Reference Figure 2 As shown, the cross-section of the fan blade 41 is arc-shaped, the arc opening angle of the fan blade 41 is 55°, and the interval opening angle between the fan blades 41 in the same group is 65°.

[0033] By adjusting the size and distribution of the fan blades 41, an airflow channel is ensured between the upper and lower sets of fan blades 41 regardless of their rotation, thus preventing undue pressure buildup.

[0034] Reference Figure 2 , Figure 4 , Figure 5 As shown, connecting rods 63 are fixed on both inner sides of the annular tube 6, and vibrating rods 64 are fixed on the inner side of the bottom of the connecting rods 63. A reciprocating cross plate 65 is connected between the two vibrating rods 64. A second guide hole 652 is provided on the reciprocating cross plate 65. An eccentric shaft 53 passes through the inside of the second guide hole 652. A cam 52 is fixed at the bottom end of the eccentric shaft 53. A through shaft 51 is fixed at the bottom axis of the cam 52. The bottom end of the through shaft 51 passes through the protective cover 5 and is coaxially connected to the lower central shaft 42.

[0035] By utilizing the cooperation of cam 52, eccentric shaft 53 and second guide hole 652, the reciprocating cross plate 65 can move back and forth, thereby reciprocatingly striking the vibrating rod 64 to cause a certain vibration of the annular tube 6 as a whole, thereby reducing the encapsulation of rising droplets on the outlet end of the atomizing nozzle 62 and avoiding phenomena such as crystallization blockage.

[0036] Reference Figure 5 As shown, the reciprocating cross plate 65 has a first guide hole 651 on both sides, and the bottom end of the vibrating rod 64 passes through the first guide hole 651. The first guide hole 651 and the second guide hole 652 are vertically distributed.

[0037] By utilizing the sliding of the eccentric shaft 53 inside the second guide hole 652, the reciprocating movement of the reciprocating cross plate 65 is realized, that is, the conversion between rotational movement and parallel movement.

[0038] Reference Figure 5 As shown, the length of the first guide hole 651 is matched with the rotation diameter of the eccentric shaft 53.

[0039] The relative arrangement of the through shaft 51 and the central shaft 42 is used to ensure the stability of the relative rotation of the cam 52 and the eccentric shaft 53.

[0040] Reference Figure 1As shown, a circulation tank 2 is provided on one side of the main body 1 of the spray tower. A circulation pump 21 is installed at the top of the circulation tank 2. One end of the circulation pump 21 is connected to the inside of the circulation tank 2 through a liquid extraction pipe 22. The other end of the circulation pump 21 is connected to one side of the annular pipe 6 through a liquid delivery pipe 23. The bottom of the circulation tank 2 is connected to one side of the salt leg 11 through a circulation pipe 25. A double filter 26 is provided on the circulation pipe 25. A replenishment pipe 24 is connected to one side of the top of the circulation tank 2.

[0041] The design incorporates a circulation tank 2 and dual filters 26 to facilitate the recycling of the original absorbent in the circulation tank 2, and the replenishment pipe 24 allows for timely replenishment of the absorbent.

[0042] Reference Figure 1 As shown, a concentration sensor is installed on one side of the circulation tank 2, and the servo motor 3, circulation pump 21, concentration sensor and airflow sensor are all connected to the PLC control system.

[0043] The PLC control system, in conjunction with a concentration sensor, can control the concentration of the absorbent in the circulation tank 2. That is, the amount of concentrate or water mixed is adjusted in real time according to the amount of absorbent circulating, so as to ensure the stability of the absorbent concentration in the circulation tank 2. The airflow sensor is used to adjust the speed of the two servo motors 3 in real time according to the changes in the air entering the air inlet pipe 13.

[0044] Working Principle: After being treated by the dust filter in the inlet pipe 13, the exhaust gas enters the main body 1 of the spray tower. At this time, the lower servo motor 3 starts, causing the lower rotating shaft 31 to drive the first bevel gear 32 to rotate, thereby meshing with the second bevel gear 43, causing the central shaft 42 to drive the fan blades 41 to rotate. This causes the lower fan blades 41 to drive the exhaust gas to rise evenly and slow down the rise of liquid droplets in the exhaust gas. At the same time, the circulation pump 21 starts, causing the absorbent liquid in the circulation tank 2 to enter the annular pipe 6 through the liquid delivery pipe 23. The absorbent liquid is then atomized by the atomizing nozzle 62 and mixes with the exhaust gas to form salts. These salts fall into the salt leg 11 under gravity. Due to the even rise of the gas, the contact between the exhaust gas and the atomized absorbent liquid is more thorough. Simultaneously, the upper servo motor 3 is started, causing the upper fan blades 41 to rotate. The blade 41 generates a downward airflow, which causes the exhaust gas to circulate in the area. At the same time, it further disperses the droplets, enhancing the reaction effect between the exhaust gas and the atomized absorbent. The atomized absorbent circulates and stagnates between the upper and lower blades 41 until the salts generated by the reaction fall into the salt leg 11 under gravity. The salts generated by the reaction precipitate in the salt leg 11 and are periodically discharged. Part of the liquid returns to the circulation tank 2 through the circulation pipe 25 and passes through the double filter 26 to remove impurities. The double filter 26 also filters the internal precipitated impurities. The circulation pump 21 is used to realize the circulation of the absorbent. At the same time, the addition of concentrated absorbent and clean water can be adjusted at any time using the replenishment pipe 24 to ensure the stability of the concentration in the circulation tank 2.

[0045] As the central shaft 42 rotates, the second bevel gear 43 rotates and drives the through shaft 51 to rotate, causing the cam 52 to drive the eccentric shaft 53 to rotate eccentrically. This causes the eccentric shaft 53 to drive the reciprocating cross plate 65 to move back and forth along the second guide hole 652, thereby causing the two side walls of the first guide hole 651 to reciprocate and alternately strike the vibrating rod 64, causing a certain vibration of the overall structure of the annular tube 6, thereby promoting the shedding of salts or droplets attached to the annular tube 6 and reducing crystallization blockage at the outlet of the atomizing nozzle 62.

[0046] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A waste gas emission spray tower for denitrification in steel plants and its usage method, characterized in that: The system includes a spray tower body (1), with a salt leg (11) connected to the bottom end of the spray tower body (1), an exhaust pipe (12) connected to the top end of the spray tower body (1), an air inlet pipe (13) connected to one side of the spray tower body (1), an annular pipe (6) fixed inside the spray tower body (1), a cross pipe (61) connected to the inner side of the annular pipe (6), atomizing nozzles (62) evenly arranged at the bottom of the annular pipe (6) and the cross pipe (61), and a ring frame (4) rotatably installed on the inner wall of the spray tower body (1) above and below the annular pipe (6). Three fan blades (41) are evenly fixed on the inner wall of the ring frame (4), and a central shaft (42) is connected to the inner side of the fan blades (41) in the same group. The central shaft (42) is located at the axis of the ring frame (4), and a second bevel gear (43) is fixed at the top end of the central shaft (42). Servo motors (3) are installed on the side wall of the spray tower body (1) at the position corresponding to the second bevel gear (43). One end of each servo motor (3) is connected to a rotating shaft (31). One end of each rotating shaft (31) extends into the interior of the spray tower body (1) and is connected to a first bevel gear (32). The first bevel gear (32) meshes with the adjacent central shaft (42). The near ends of the rotating shaft (31) and the adjacent central shaft (42) are fitted with a protective cover (5). The two sets of fan blades (41) have opposite flow directions. The fan blade (41) located below guides upwards, and the fan blade (41) located above guides downwards. The rotation speed of the fan blade (41) located above is less than that of the fan blade (41) located below. The air outlet of the air inlet pipe (13) is located below the bottom fan blade (41). An airflow sensor is installed at the air inlet of the exhaust pipe (12).

2. The waste gas emission spray tower for steel plant denitrification and its usage method as described in claim 1, characterized in that: A demister is provided inside the spray tower body (1) at one end near the exhaust pipe (12), and a dust filter is provided at one end of the air inlet pipe (13) near the exhaust port.

3. The waste gas emission spray tower for steel plant denitrification and its usage method according to claim 1, characterized in that: The cross-section of the fan blade (41) is arc-shaped, the arc opening angle of the fan blade (41) is 55°, and the interval opening angle between the fan blades (41) in the same group is 65°.

4. The waste gas emission spray tower for steel plant denitrification and its usage method according to claim 1, characterized in that: Both inner sides of the annular tube (6) are fixed with connecting rods (63), and the inner sides of the bottom of the connecting rods (63) are fixed with vibrating rods (64). The two vibrating rods (64) are connected together by a reciprocating cross plate (65). A second guide hole (652) is provided on the reciprocating cross plate (65). An eccentric shaft (53) passes through the inside of the second guide hole (652). A cam (52) is fixed at the bottom end of the eccentric shaft (53). A through shaft (51) is fixed at the bottom axis of the cam (52). The bottom end of the through shaft (51) passes through the protective cover (5) and is coaxially connected with the lower central shaft (42).

5. The waste gas emission spray tower for steel plant denitrification and its usage method according to claim 4, characterized in that: The reciprocating cross plate (65) has a first guide hole (651) on both sides, and the bottom end of the vibrating rod (64) passes through the first guide hole (651). The first guide hole (651) and the second guide hole (652) are vertically distributed.

6. The waste gas emission spray tower for steel plant denitrification and its usage method according to claim 5, characterized in that: The length of the first guide hole (651) is matched with the rotation diameter of the eccentric shaft (53).

7. The waste gas emission spray tower for steel plant denitrification and its usage method according to claim 1, characterized in that: A circulation tank (2) is provided on one side of the main body (1) of the spray tower. A circulation pump (21) is installed at the top of the circulation tank (2). One end of the circulation pump (21) is connected to the inside of the circulation tank (2) through a liquid extraction pipe (22). The other end of the circulation pump (21) is connected to one side of the ring pipe (6) through a liquid delivery pipe (23). The bottom end of the circulation tank (2) is connected to one side of the salt leg (11) through a circulation pipe (25). A double filter (26) is provided on the circulation pipe (25). A replenishment pipe (24) is connected to one side of the top of the circulation tank (2).

8. The waste gas emission spray tower for steel plant denitrification and its usage method according to claim 7, characterized in that: A concentration sensor is provided on one side of the circulation tank (2), and the servo motor (3), circulation pump (21), concentration sensor and airflow sensor are all connected to the PLC control system.

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