Coal-fired flue gas desulfurization system

Abstract

A flue gas desulfurization system for purifying sulfur-containing flue gas generated by coal-fired equipment in factories includes a desulfurization tower body. A spiral inlet duct at the bottom of the tower body is designed to lift the flue gas upwards. Inside the tower body, from bottom to top, are a flue gas dispersion seat and a first desulfurizing agent injection section. The flue gas dispersion seat is an inverted conical seat, supported by a support member and positioned in the middle of the tower body, with its axis coaxial with the tower body's axis. In this invention, the sulfur-containing flue gas flows spirally upwards through the spiral inlet duct towards the top of the tower body. Under the action of the flue gas dispersion seat, the flue gas is dispersed, causing most of it to flow towards a variable-diameter spiral tube in the opposite direction of its rotation. Alkaline powder injected through the first desulfurizing agent nozzle comes into direct contact with and reacts with the sulfur-containing flue gas, prolonging the reaction time between the flue gas and the alkaline powder within the tower body, improving desulfurization efficiency, and reducing powder waste.

Description

Technical Field

[0001] This invention relates to the field of flue gas desulfurization technology, specifically a coal-fired flue gas desulfurization system. Background Technology

[0002] Sulfur dioxide is one of the air pollutants, mainly from the combustion of fossil fuels. To reduce sulfur dioxide emissions, desulfurization treatment is required for the sulfur-containing flue gas produced by fossil fuel combustion. The common mainstream desulfurization methods are wet desulfurization and dry desulfurization. In the dry desulfurization process, the flue gas is discharged from the bottom of the desulfurization tower and comes into countercurrent contact with the desulfurizing agent injected by the desulfurizing agent injection device at the top of the desulfurization tower to achieve a desulfurization reaction. Then it is discharged from the top of the desulfurization tower for further treatment.

[0003] A dry desulfurization device for a lime rotary kiln, with patent number CN112546848B, discloses the installation of powder spraying components, swirl plates, and turbulence components inside the kiln. When the flue gas flows through the swirl plates, the shearing force of the swirl blades forms a vortex-like airflow, which then impacts the swinging blades of the turbulence components, forming a chaotic airflow. This increases the contact time and contact area between the airflow and the alkaline powder, thereby improving the desulfurization efficiency and the effective utilization rate of the alkaline powder. The large amount of flue gas entering the device from the flue gas inlet can only be discharged through the swirl holes. Although it can disperse the flue gas into multiple disordered airflows, the alkaline powder sprayed by the powder spraying component cannot be sprayed directly in the upward direction of the flue gas flow. Instead, it can only cover the disordered flue gas by spraying a large amount of alkaline powder, which results in the waste of alkaline powder. Because there is a certain cavity between the swirl plate and the anti-settling plate, most of the flue gas entering from the flue gas inlet will remain between the swirl plate and the anti-settling plate, which will reduce the temperature of the high-temperature flue gas and is not conducive to the activation of alkaline powder by the high-temperature flue gas, thus affecting the desulfurization effect. Furthermore, if the desulfurization products generated by the reaction between alkaline powder and flue gas are not cleaned for a long time, they will cause the nozzle to become clogged, affecting the amount of alkaline powder sprayed. Summary of the Invention

[0004] To address the technical problems mentioned above, this invention provides a coal-fired flue gas desulfurization system that extends the reaction time between sulfur-containing flue gas and alkaline powder within the desulfurization tower, thereby improving the desulfurization effect and reducing powder waste.

[0005] The technical solution of this invention is as follows:

[0006] A coal-fired flue gas desulfurization system is used to purify sulfur-containing flue gas generated by coal-fired equipment in a factory. It includes a desulfurization tower body, a spiral flue gas inlet duct at the bottom of the desulfurization tower body that can spirally lift the flue gas upwards, and a flue gas dispersion seat and a first desulfurizing agent injection section arranged from bottom to top inside the desulfurization tower body.

[0007] The flue gas dispersion seat is an inverted conical seat. The conical seat is set in the middle of the desulfurization tower body through a support member, and the axis of the conical seat is set coaxially with the axis of the desulfurization tower body.

[0008] The first desulfurizing agent injection section includes a variable diameter spiral tube disposed on a conical seat and multiple first desulfurizing agent nozzles disposed on the lower surface of the variable diameter spiral tube. The upper end of the variable diameter spiral tube is connected to an external automatic desulfurizing agent feeding device through a first pipe. The spiral inner diameter of the variable diameter spiral tube decreases from top to bottom and the spiral direction is opposite to that of the spiral flue. The minimum diameter at the lower end of the variable diameter spiral tube is greater than the maximum diameter at the upper end of the conical seat. The nozzle of the first desulfurizing agent nozzle is inclined downward along the downward spiral direction of the variable diameter spiral tube.

[0009] The conical seat is provided with a second desulfurizing agent injection section that is taller than the first desulfurizing agent injection section and can move up and down. The lower part of the second desulfurizing agent injection section is provided with several second desulfurizing agent nozzles with adjustable injection diameter, and the upper part is provided with an openable and closable concealed injection port.

[0010] A flue gas inlet pipe is connected to the outer bottom of the desulfurization tower body. Sulfur-containing flue gas generated by the coal-fired equipment enters the spiral flue gas inlet duct at the bottom of the desulfurization tower body through this pipe. The spiral flue gas inlet duct is spiral-shaped, causing the sulfur-containing flue gas to flow upwards in a spiral pattern towards the upper part of the desulfurization tower body. This extends the flow path of the flue gas within the limited height of the desulfurization tower. A flue gas dispersion seat inside the desulfurization tower body further disperses most of the spirally upward sulfur-containing flue gas to the outside of the variable-diameter spiral pipe. The dispersed sulfur-containing flue gas can directly contact and react with the alkaline powder sprayed by the first desulfurizing agent nozzle, thus extending the flow path of the sulfur-containing flue gas during desulfurization. The reaction time between the sulfur tower body and the alkaline powder can be optimized to fully utilize the alkaline powder and reduce its waste. A portion of the sulfur-containing flue gas rising from the flue gas dispersion seat will also flow into the variable-diameter spiral tube under the spiral upward action of the sulfur-containing flue gas. Alkaline powder injected by the second desulfurizing agent injection unit is used to desulfurize the sulfur-containing flue gas flowing into the variable-diameter spiral tube. Furthermore, the second desulfurizing agent injection unit can control the opening and closing of the concealed injection port and the injection diameter of the second desulfurizing agent nozzle according to the amount of sulfur-containing flue gas entering the tube, thereby automatically adjusting the amount of alkaline powder injected and reducing its waste.

[0011] The structure of the second desulfurizing agent injection section is as follows: the second desulfurizing agent injection section includes a vertical spray pipe, a lifting assembly is installed inside the conical seat, the top of the lifting assembly is connected to the vertical spray pipe, the lower end of the vertical spray pipe is a closed end, the top is a feed inlet, and a feed sleeve is sleeved on the top. The upper end of the feed sleeve is connected to the discharge port of the external automatic desulfurizing agent feeding device through a second pipe. The side wall of the feed sleeve is provided with multiple through first discharge ports within the moving range of the vertical spray pipe, which can communicate with the inside of the feed sleeve when the vertical spray pipe moves downward.

[0012] According to the above structure, the second desulfurizing agent nozzle is positioned such that multiple second desulfurizing agent nozzles are connected to the vertical spray pipe along the axial direction, and each second desulfurizing agent nozzle is movably connected to the vertical spray pipe and is inclined downwards.

[0013] The connection between the second desulfurizing agent nozzle and the vertical spray pipe is as follows: the vertical spray pipe has an opening for installing the second desulfurizing agent nozzle, the tube body of the second desulfurizing agent nozzle passes through the opening and is hinged to the vertical spray pipe through a hinge rod, and a first feed port is opened on the upper part of one side of the tube body located inside the vertical spray pipe.

[0014] If the desulfurization products generated by the reaction of alkaline powder with flue gas are not cleaned for a long time, they will cause the nozzle to become clogged and affect the amount of alkaline powder sprayed. Therefore, a descaling mechanism is installed under the conical seat to clean the dirt on the front of the first desulfurizing agent nozzle.

[0015] The specific structure of the descaling mechanism is as follows: the descaling mechanism includes multiple annular pipes of different diameters and multiple descaling nozzles installed on the annular pipes. The multiple annular pipes are connected and connected to an external descaling agent delivery chamber through a third pipe. The descaling agent in the descaling agent delivery chamber can be a descaling agent corresponding to the desulfurization products or water. The descaling agent can be sprayed onto the descaling nozzles. After the descaling agent reacts with and loosens the desulfurization products, the descaling agent is replaced with clean water. The clean water is used to clean the descaling nozzles and the waste liquid falls into the waste liquid collection chamber at the bottom of the desulfurization tower body. The waste liquid collection chamber is located above the spiral flue gas inlet and does not affect the spiral flue gas inlet from delivering sulfur-containing flue gas into the desulfurization tower body.

[0016] To ensure that the descaling nozzle can spray upwards onto the front of the corresponding first desulfurizing agent nozzle, the descaling nozzle is tilted upwards so that the front of the descaling nozzle is opposite to the front of the tilted first desulfurizing agent nozzle.

[0017] The descaling nozzles are tilted upwards and can be blocked by the alkaline powder sprayed when the first desulfurizing agent nozzle is working. To reduce the clogging of the descaling nozzles, a nozzle blocking assembly is installed above the annular pipe. The nozzle blocking assembly can block multiple descaling nozzles and can be rotated at a certain angle to stagger the descaling nozzles.

[0018] The nozzle shielding assembly is structured as follows: the nozzle shielding assembly includes a cover plate corresponding to multiple annular tubes, the cover plate has a through hole corresponding to the descaling nozzle, and the cover plate is driven to rotate by a rotating assembly.

[0019] When spraying descaling agent, the cover plate needs to be staggered from the descaling nozzle to avoid the cover plate blocking the descaling agent from being sprayed out. The rotating component includes a first bevel gear and a second bevel gear set in a conical seat. The first bevel gear and the second bevel gear mesh with each other. The first bevel gear is connected to the middle of the cover plate through a vertically set first central shaft. The second bevel gear is connected to the drive motor on the outside of the desulfurization tower body through a second central shaft, and is driven to rotate by the drive motor.

[0020] The beneficial effects of this invention are that the sulfur-containing flue gas flows spirally towards the upper part of the desulfurization tower body through the spiral flue gas inlet. Under the action of the flue gas dispersion seat, the sulfur-containing flue gas is dispersed, so that most of the sulfur-containing flue gas flows towards the variable diameter spiral tube opposite to its spiral direction. The alkaline powder sprayed through the first desulfurizing agent nozzle comes into direct contact with the sulfur-containing flue gas and reacts, prolonging the reaction time of the sulfur-containing flue gas with the alkaline powder in the desulfurization tower body, improving the desulfurization effect, and reducing the waste of powder.

[0021] For the portion of sulfur-containing flue gas that escapes to the upper part of the variable diameter spiral tube after passing through the flue gas dispersion seat, the second desulfurizing agent injection unit removes the sulfur-containing flue gas through a separation reaction. The second desulfurizing agent injection unit can control the opening and closing of the hidden injection port according to the flue gas inlet volume of sulfur-containing flue gas, control the injection diameter of the second desulfurizing agent nozzle, realize automatic adjustment of the amount of alkaline powder injected, and further reduce the waste of alkaline powder. Attached Figure Description

[0022] In the attached diagram:

[0023] Figure 1 This is a schematic diagram of the cross-sectional structure;

[0024] Figure 2 for Figure 1 Enlarged structural diagram at point A in the middle;

[0025] Figure 3 for Figure 1 Enlarged structural diagram at point B;

[0026] Figure 4 for Figure 1 Enlarged structural diagram at point C;

[0027] Figure 5 A schematic diagram of the first desulfurizing agent injection section and the descaling mechanism;

[0028] Figure 6 for Figure 5 Enlarged structural diagram at point D;

[0029] Figure 7 This is a schematic diagram of the cover plate structure;

[0030] Figure 8 This is a schematic diagram of a ring-shaped pipe structure;

[0031] Figure 9 This is a front view;

[0032] The components represented by the various reference numerals in the diagram are:

[0033] 1. Desulfurization tower body; 2. Flue gas dispersion seat; 21. Flue gas duct; 3. Variable diameter spiral pipe; 4. First desulfurizing agent nozzle; 5. Automatic desulfurizing agent feeding device; 6. Vertical spray pipe; 61. Opening; 7. Second desulfurizing agent nozzle; 71. First feed inlet; 72. Pipe body; 73. Second discharge outlet; 8. Feed sleeve; 81. First discharge outlet; 9. Lifting assembly; 10. Hinge rod; 11. Flue gas inlet pipe; 12. Exhaust chimney; 13. Ring 14. Descaling nozzle; 15. Descaling agent delivery chamber; 16. Cover plate; 161. Through hole; 17. First bevel gear; 18. Second bevel gear; 19. First central shaft; 20. Second central shaft; 21. Drive motor; 22. Support component; 23. First pipe; 24. Second pipe; 25. Third pipe; 26. Demister; 27. First electric discharge valve; 28. Second electric discharge valve; 29. ​​Third electric discharge valve. Detailed Implementation

[0034] like Figure 1 , Figure 9 The system shown is a coal-fired flue gas desulfurization system used to purify sulfur-containing flue gas generated by coal-fired equipment in a factory. It includes a desulfurization tower body 1, with an inlet pipe 11 connected to the outer side of the bottom of the desulfurization tower body 1. A spiral inlet duct capable of spirally lifting the flue gas upwards is provided at the bottom of the desulfurization tower body 1. The interior of the desulfurization tower body 1 is provided from bottom to top with a descaling mechanism, a flue gas dispersion seat 2, a first desulfurizing agent injection section and a demister 26. An exhaust chimney 12 is provided at the upper end of the desulfurization tower body 1.

[0035] The flue gas dispersion seat 2 is an inverted conical seat. Multiple flue gas inlet grooves 21 are formed along the generatrix of the conical surface. The extension line of the axis of the flue gas inlet groove 21 is located inside the variable-diameter spiral pipe 3, and the cross-section of the flue gas inlet groove 21 is set in an arc shape or an irregular shape. The conical seat is set in the middle of the desulfurization tower body 1 by a support member 22, which is a transverse support rod set laterally on the inner wall of the desulfurization tower body 1. The upper part of the flue gas dispersion seat 2 is fixedly connected to the transverse support rod. Furthermore, the axis of the conical seat is coaxial with the axis of the desulfurization tower body 1, which facilitates the dispersion of the spirally rising sulfur-containing flue gas in the middle of the desulfurization tower body 1. The dispersed sulfur-containing flue gas, compared to the scattered and disordered sulfur-containing flue gas, is more conducive to the desulfurization reaction through the injection of the first desulfurizing agent, reducing the waste of alkaline powder.

[0036] Among them, such as Figure 5 , Figure 6As shown, the first desulfurizing agent injection section includes a variable diameter spiral tube 3 mounted on a conical seat and multiple first desulfurizing agent nozzles 4 connected to the lower surface of the variable diameter spiral tube 3. The upper port of the variable diameter spiral tube 3 is connected to an external automatic desulfurizing agent feeding device 5 through a first pipe 23. A first electric discharge valve 27 capable of controlling the amount of alkaline powder sprayed is provided on the first pipe 23. The spiral inner diameter of the variable diameter spiral tube 3 decreases sequentially from top to bottom, and the direction of rotation is opposite to that of the spiral flue gas inlet. The minimum diameter at the lower end of the variable diameter spiral tube 3 is greater than the maximum diameter at the upper end of the conical seat. The nozzles of the first desulfurizing agent nozzles 4 are inclined downward along the downward rotation direction of the variable diameter spiral tube 3.

[0037] The sulfur-containing flue gas generated by the coal-fired equipment enters the spiral flue gas inlet duct at the bottom of the desulfurization tower body 1 through the flue gas inlet pipe 11. The spiral flue gas inlet duct is spiral-shaped inside, causing the sulfur-containing flue gas to flow upwards in a spiral shape towards the upper part of the desulfurization tower body 1. The spiral flue gas inlet duct is existing technology and will not be described in detail here. The flue gas dispersion seat 2 set inside the desulfurization tower body 1 can further disperse most of the sulfur-containing flue gas spirally upwards to the outside of the variable diameter spiral pipe 3, so that most of the sulfur-containing flue gas can come into direct contact with and react with the alkaline powder sprayed by the first desulfurizing agent nozzle 4 at different heights on the variable diameter spiral pipe 3. The aforementioned first desulfurizing agent nozzle 4 can react fully with the sulfur-containing flue gas in stages. Moreover, multiple first desulfurizing agent nozzles 4 are arranged along the downward spiral direction of the variable diameter spiral tube 3, which can spray alkaline powder downward at an angle along the spiral direction of the variable diameter spiral tube 3. This allows them to come into contact with the sulfur-containing flue gas that is spiraling upward in the opposite direction, which can prolong the reaction time of the sulfur-containing flue gas with the alkaline powder in the desulfurization tower body 1, and make full use of the alkaline powder, thereby reducing the waste of alkaline powder.

[0038] The sulfur-containing flue gas rising from the flue gas dispersion seat 2 will also flow into the variable diameter spiral tube 3 under the spiral upward action of the sulfur-containing flue gas. This part of the desulfurized flue gas is the escape flue gas. For this reason, a second desulfurizing agent injection section with a height greater than the first desulfurizing agent injection section and capable of moving up and down is provided on the conical seat. The lower part of the second desulfurizing agent injection section is provided with several second desulfurizing agent nozzles 7 with adjustable injection diameters, and the upper part is provided with an openable and closable concealed injection port. The alkaline powder sprayed through the second desulfurizing agent nozzles 7 is used to desulfurize the escape flue gas. The second desulfurizing agent injection section can control the opening and closing of the concealed injection port and the injection diameter of the second desulfurizing agent nozzles 7 according to the flue gas inlet volume containing sulfur, so as to automatically adjust the amount of alkaline powder sprayed and reduce the waste of alkaline powder.

[0039] like Figure 2 , Figure 4As shown, the structure of the second desulfurizing agent injection section is as follows: the second desulfurizing agent injection section includes a vertical spray pipe 6, and a lifting assembly 9 is installed in the conical seat. The lifting assembly 9 is an electric push rod, a hydraulic cylinder or other type of lifting tool. The output end of the top of the lifting assembly 9 is connected to the vertical spray pipe 6. The lifting assembly 9 can drive the vertical spray pipe 6 to move up and down. The lower end of the vertical spray pipe 6 is a closed end, and the top is a feed inlet. A feed sleeve 8 is sleeved on the top. The upper end of the feed sleeve 8 is connected to the outlet of the external automatic desulfurizing agent feeding device 5 through the second pipe 24. A second electric discharge valve 28 that can control the amount of alkaline powder sprayed is installed on the second pipe 24. Multiple through first discharge ports 81 are provided on the side wall of the feed sleeve 8 within the moving range of the vertical spray pipe 6. The multiple first discharge ports 81 are circumferentially distributed in the lower part of the vertical spray pipe 6, so that the first discharge ports 81 can communicate with the inside of the feed sleeve 8 when the vertical spray pipe 6 moves down.

[0040] Based on the above-mentioned automatic adjustment of the alkaline powder spraying volume, a gas sensor is installed at the exhaust port of the spiral flue. The gas sensor is existing technology and is not shown in the figure. The gas sensor is electrically connected to the first electric discharge valve 27, the second electric discharge valve 28 and the lifting assembly 9 respectively. When there is a lot of sulfur-containing flue gas, the first electric discharge valve 27 and the second electric discharge valve 28 are controlled to increase the discharge volume, and the lifting assembly 9 is controlled to drive the vertical nozzle 6 to move down, so that the upper end of the vertical nozzle 6 moves down, and the first discharge port 81 is connected to the feed sleeve 8, thereby increasing the spraying range and spraying volume of alkaline powder and improving the desulfurization effect of sulfur-containing flue gas.

[0041] According to the above structure, the second desulfurizing agent nozzles 7 are positioned such that multiple second desulfurizing agent nozzles 7 are connected along the axial direction of the vertical spray pipe 6. These nozzles are alternately arranged around the vertical spray pipe 6, allowing for desulfurization of some sulfur-containing flue gas at different angles and heights within the variable-diameter spiral tube 3. The first desulfurizing agent nozzles 4 above the variable-diameter spiral tube 3 are concentrated on the outer side. Desulfurization in the middle position is supplemented by alkaline powder sprayed from the second desulfurizing agent nozzles 7. Since the sulfur-containing flue gas escaping to the middle position above the variable-diameter spiral tube 3 cannot undergo complete desulfurization, to increase the spray range and amount of alkaline powder in the middle position above the variable-diameter spiral tube 3, the nozzle diameters of the multiple second desulfurizing agent nozzles 7 gradually decrease from top to bottom. This allows for flexible spraying of alkaline powder according to the flow rate of the sulfur-containing flue gas, reducing the waste of alkaline powder.

[0042] like Figure 3As shown, the connection between the second desulfurizing agent nozzle 7 and the vertical spray pipe 6 is such that a single second desulfurizing agent nozzle 7 is movably connected to the vertical spray pipe 6 and is inclined downward. Specifically, the vertical spray pipe 6 has an opening 61 for installing the second desulfurizing agent nozzle 7. The tube body 72 of the second desulfurizing agent nozzle 7 passes through the opening 61 and is hinged to the vertical spray pipe 6 through the hinge rod 10. A first feed port 71 is provided on the upper part of one side of the tube body 72 located inside the vertical spray pipe 6. The shape of the first feed port 71 can be elliptical, circular, rectangular, or irregular. The second desulfurizing agent nozzle 7 is initially positioned at an angle downwards. The first inlet 71 and the vertical nozzle 6 have a certain angle, resulting in a smaller feed rate. When the amount of sulfur-containing flue gas entering the system increases, the second electric discharge valve 28 increases the discharge rate, increasing the amount of alkaline powder in the vertical nozzle 6. This creates a greater impact force on the upper part of the tube body 72 located inside the vertical nozzle 6, causing the second desulfurizing agent nozzle 7 to swing irregularly upwards. The angle between the first inlet 71 and the vertical nozzle 6 decreases, increasing the feed area and allowing for flexible control of the alkaline powder discharge. An arc-shaped plate is located on the lower side of the nozzle body of the tube body 72 away from the second desulfurizing agent nozzle 7, with the arc pointing upwards. This increases the contact area with the alkaline powder inside the vertical nozzle 6, facilitating adjustment of the swing of the second desulfurizing agent nozzle 7 within the opening 61. The section of the vertical spray pipe 6 between the second desulfurizing agent nozzle 7 at the bottom and the upper end of the output end of the lifting assembly 9 is set as a solid section. The section of the vertical spray pipe 6 between the second desulfurizing agent nozzle 7 and the solid section is provided with a second discharge port 73 for spraying alkaline powder from below the vertical spray pipe 6.

[0043] If the desulfurization products generated by the reaction of alkaline powder with flue gas are not cleaned for a long time, they will cause the nozzle to become clogged and affect the amount of alkaline powder sprayed. Therefore, a descaling mechanism is installed under the conical seat to clean the dirt on the front of the first desulfurizing agent nozzle 4.

[0044] Among them, such as Figure 7 , Figure 8As shown, the specific structure of the descaling mechanism is as follows: the descaling mechanism includes multiple annular pipes 13 of different diameters and multiple descaling nozzles 14 disposed on the annular pipes 13. The multiple annular pipes 13 are connected and connected to an external descaling agent delivery chamber 15 through a third pipe 25. A third electric discharge valve 29 is disposed on the third pipe 25 to control the amount of descaling agent sprayed. The descaling agent in the descaling agent delivery chamber 15 can be set to descaling agent corresponding to the desulfurization products. The descaling agent is used to remove desulfurization products. It can be sprayed into the descaling nozzle 14 and allowed to react and loosen the desulfurization products. After using the descaling agent, it can be replaced with water to clean the descaling nozzle 14. The waste liquid falls into the waste liquid collection chamber at the bottom of the desulfurization tower body 1. A baffle can be installed above the spiral flue to form a waste liquid collection chamber, which is not shown in the figure. The waste liquid collection chamber does not affect the spiral flue to transport sulfur-containing flue gas into the desulfurization tower body 1. The waste liquid collection chamber is connected to the outside of the desulfurization tower body 1 and is used to clean the waste liquid.

[0045] To ensure that the descaling nozzle 14 can spray upwards onto the front of the corresponding first desulfurizing agent nozzle 4, the descaling nozzle 14 is tilted upwards, so that the front of the descaling nozzle 14 is opposite to the front of the tilted first desulfurizing agent nozzle 4.

[0046] The descaling nozzle 14 is tilted upwards and may become clogged by the alkaline powder sprayed when the first desulfurizing agent nozzle 4 is working. To reduce clogging of the descaling nozzle 14, a nozzle blocking assembly is provided above the annular pipe 13. The nozzle blocking assembly can block multiple descaling nozzles 14 and can rotate at a certain angle to offset the descaling nozzles 14. The nozzle blocking assembly includes a cover plate 16 corresponding to multiple annular pipes 13. The cover plate 16 has an annular structure and an arc-shaped cross-section. In this embodiment, there are two annular pipes 13 with different diameters, so two cover plates 16 with different diameters are provided. The two cover plates 16 are fixedly connected by a connecting bracket. The cover plate 16 has a through hole 161 corresponding to the descaling nozzle 14. The cover plate 16 is driven to rotate by a rotating assembly.

[0047] When spraying descaling agent, the cover plate 16 needs to be staggered from the descaling nozzle 14 to avoid the cover plate 16 blocking the descaling agent from being sprayed out. The rotating component includes a first bevel gear 17 and a second bevel gear 18 set in a conical seat. The first bevel gear 17 and the second bevel gear 18 mesh with each other. The first bevel gear 17 is fixedly connected to the middle of the connecting frame of the cover plate 16 through a vertically set first central shaft 19. The second bevel gear 18 is connected to the drive motor 21 on the outside of the desulfurization tower body 1 through a second central shaft 20, and is driven to rotate by the drive motor 21. The rotation of the second bevel gear 18 drives the first bevel gear 17 to rotate, and then drives the cover plate 16 to rotate and move by an angle through the first central shaft 19 to avoid the cover plate 16 blocking the descaling agent from being sprayed out.

Claims

1. A coal-fired flue gas desulfurization system for purifying sulfur-containing flue gas generated by a coal-fired plant, comprising a desulfurization tower body (1), wherein a spiral flue capable of spirally lifting the flue gas upward is arranged at the bottom of the desulfurization tower body (1), characterized in that, The desulfurization tower body (1) is provided with a flue gas dispersion seat (2) and a first desulfurizing agent injection section from bottom to top inside; The flue gas dispersion seat (2) is an inverted conical seat. The conical seat is set in the middle of the desulfurization tower body (1) by a support member (22), and the axis of the conical seat is coaxial with the axis of the desulfurization tower body (1). The first desulfurizing agent injection section includes a variable diameter spiral tube (3) disposed on a conical seat and a plurality of first desulfurizing agent nozzles (4) connected to the lower surface of the variable diameter spiral tube (3). The upper port of the variable diameter spiral tube (3) is connected to an external automatic desulfurizing agent feeding device (5) through a first pipe (23). The spiral inner diameter of the variable diameter spiral tube (3) decreases from top to bottom and the spiral direction is opposite to the spiral direction of the spiral flue. The minimum diameter of the lower end of the variable diameter spiral tube (3) is greater than the maximum diameter of the upper end face of the conical seat. The nozzle of the first desulfurizing agent nozzle (4) is inclined downward along the downward spiral direction of the variable diameter spiral tube (3). The conical seat is provided with a second desulfurizing agent injection section that is taller than the first desulfurizing agent injection section and can move up and down. The lower part of the second desulfurizing agent injection section is provided with several second desulfurizing agent nozzles (7) with adjustable injection diameter, and the upper part is provided with an openable and closable hidden injection port. The second desulfurizing agent injection section includes a vertical spray pipe (6), and a lifting assembly (9) is provided inside the conical seat. The top of the lifting assembly (9) is connected to the vertical spray pipe (6). The lower end of the vertical spray pipe (6) is a closed end, and the top is a feed inlet. A feed sleeve (8) is sleeved on the top. The upper end of the feed sleeve (8) is connected to the external automatic desulfurizing agent feeding device (5) through a second pipe (24). The side wall of the feed sleeve (8) is provided with multiple through first discharge ports (81) within the moving range of the vertical spray pipe (6), which can communicate with the inside of the feed sleeve (8) when the vertical spray pipe (6) moves down. The vertical nozzle (6) is connected to multiple second desulfurizing agent nozzles (7) along the axial direction. Each second desulfurizing agent nozzle (7) is movably connected to the vertical nozzle (6) and is inclined downward.

2. The flue gas desulfurization system according to claim 1, characterized in that, The vertical nozzle (6) has an opening (61) for installing a second desulfurizing agent nozzle (7). The tube body (72) of the second desulfurizing agent nozzle (7) passes through the opening (61) and is hinged to the vertical nozzle (6) by a hinge rod (10). The tube body (72) located inside the vertical nozzle (6) has a first feed port (71) on the upper part of one side.

3. The flue gas desulfurization system according to claim 1, characterized in that, A descaling mechanism is provided below the conical seat to clean the dirt on the front of the first desulfurizing agent nozzle (4).

4. A coal-fired flue gas desulfurization system according to claim 3, characterized in that, The descaling mechanism includes multiple annular pipes (13) of different diameters and multiple descaling nozzles (14) arranged on the annular pipes (13). The multiple annular pipes (13) are connected in series and connected to an external descaling agent delivery chamber (15) through a third pipe (25).

5. A coal-fired flue gas desulfurization system according to claim 4, characterized in that, The descaling nozzle (14) is tilted upwards, so that the front of the descaling nozzle (14) is opposite to the front of the first desulfurizing agent nozzle (4) which is tilted upwards.

6. A coal-fired flue gas desulfurization system according to claim 4, characterized in that, A nozzle blocking assembly is provided above the annular tube (13). The nozzle blocking assembly can block multiple descaling nozzles (14) and can rotate at a certain angle to offset the descaling nozzles (14).

7. A coal-fired flue gas desulfurization system according to claim 6, characterized in that, The nozzle shielding assembly includes a cover plate (16) corresponding to a plurality of annular tubes (13). The cover plate (16) has a through hole (161) corresponding to the descaling nozzle (14). The cover plate (16) is driven to rotate by a rotating assembly.

8. A coal-fired flue gas desulfurization system according to claim 7, characterized in that, The rotating assembly includes a first bevel gear (17) and a second bevel gear (18) disposed in a conical seat and meshing with each other. The first bevel gear (17) is connected to the middle of the cover plate (16) through a vertically arranged first central shaft (19), and the second bevel gear (18) is connected to a drive motor (21) on the outside of the desulfurization tower body (1) through a second central shaft (20), and is driven to rotate by the drive motor (21).

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