A desulfurization and dust removal device for a semi-dry flue gas desulfurization system

Abstract

This utility model discloses a desulfurization and dust removal device for a semi-dry flue gas desulfurization system, including a lime slurry preparation tank, a desulfurizer, and a bag filter. The desulfurizer is internally divided into a primary desulfurization chamber and a secondary desulfurization chamber by a middle partition. Both the primary and secondary desulfurization chambers have dust collection cones at their bottoms. A flue gas inlet channel is located at the lower part of the primary desulfurization chamber, with one or two atomizing spray guns at the inlet end. The lower end of the Venturi mixing pipe inside the primary desulfurization chamber is connected to the flue gas inlet channel. A rotary spray assembly is installed inside the secondary desulfurization chamber, with a settling assembly below it. A connecting hole is provided on the middle partition above the settling assembly. A flue gas guide pipe connected to the inlet of the bag filter is installed on the secondary desulfurization chamber. The lime slurry preparation tank is connected to the rotary spray assembly and atomizing spray guns via a slurry delivery pipeline. This device not only improves the flue gas desulfurization effect but also increases the desulfurization efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of steelmaking production technology, specifically relating to a desulfurization and dust removal device for a semi-dry flue gas desulfurization system. Background Technology

[0002] Steel production is a typical high-energy-consuming and high-polluting process. Its flue gas emissions contain large amounts of sulfur dioxide, a major culprit in environmental problems such as acid rain and smog. Sulfur dioxide emissions do not originate solely from the steelmaking process, but are primarily concentrated in the upstream sintering (pelletizing) and coking processes. There are many types of flue gas desulfurization technologies, which can be classified into three main categories based on the form of the desulfurizing agent and the dry / wet state of the reaction products: wet, dry, and semi-dry methods. Semi-dry desulfurization technology uses alkaline powdered or slurry absorbents (such as slaked lime Ca(OH)2) to react with SO2 in the flue gas in a reaction tower, resulting in a gas-solid / gas-liquid reaction. The reaction products are dry, with moisture evaporated. The reaction products are then separated into gas and solid components to achieve desulfurization. In existing technologies, the semi-dry desulfurization system mainly includes a lime slurry preparation tank, a desulfurization tower, and a bag filter. During operation, flue gas enters from the bottom of the desulfurizer. Lime slurry from the preparation tank is sprayed from the bottom of the desulfurization tower via atomizing spray guns. The sprayed lime slurry mixes and reacts with the flue gas within the tower. The resulting flue gas reactants enter the bag filter. After treatment by the bag filter, solid lime particles in the flue gas are discharged from the bottom of the bag filter, and the flue gas exits from the outlet of the bag filter. This desulfurization and dust removal system effectively removes sulfur dioxide and dust. The reactants are dry powder, and no wastewater is generated during the reaction. However, the existing desulfurization tower structure is relatively rudimentary. During the mixing process of flue gas and lime slurry sprayed from the nozzles within the desulfurization tower, uniform mixing of the lime slurry and flue gas cannot be achieved effectively, resulting in low reaction efficiency and unsatisfactory desulfurization. Furthermore, the reactants generated within the desulfurization tower directly enter the bag filter for gas-solid separation, placing a heavy burden on the bag filter. The bag filter frequently experiences clogging during operation, requiring frequent maintenance and severely impacting desulfurization efficiency. Therefore, it is objectively necessary to develop a desulfurization and dust removal device for a semi-dry flue gas desulfurization system with a reasonable structure that can improve both desulfurization effect and efficiency. Summary of the Invention

[0003] The purpose of this utility model is to provide a desulfurization and dust removal device for a semi-dry flue gas desulfurization system that has a reasonable structure and can improve both the desulfurization effect and the desulfurization efficiency.

[0004] The purpose of this utility model is achieved as follows: It includes a lime slurry preparation tank, a desulfurizer, and a bag filter. The desulfurizer has a vertically installed intermediate partition, which divides the internal cavity of the desulfurizer into a primary desulfurization chamber and a secondary desulfurization chamber. Both the primary and secondary desulfurization chambers have ash collection cones at their bottoms, with ash discharge pipes at the bottom of the ash collection cones and ash discharge valves on the ash discharge pipes. A flue gas inlet channel runs through the lower part of the primary desulfurization chamber, and one or two atomizing spray guns are inclinedly installed at the upper part of the inlet end of the flue gas inlet channel. The interior of the primary desulfurization chamber is connected by supports... A Venturi mixing pipe is vertically installed on the support plate. The lower end of the Venturi mixing pipe is connected to the flue gas inlet channel. A rotary spray assembly is installed inside the secondary desulfurization chamber. A settling assembly is installed in the secondary desulfurization chamber below the rotary spray assembly. A connecting hole is provided on the middle partition on the upper side of the settling assembly. A flue gas guide pipe connected to the inlet of the bag filter is installed on the secondary desulfurization chamber below the settling assembly. An exhaust pipe is installed at the outlet of the bag filter. An induced draft fan is installed on the exhaust pipe. The lime slurry preparation tank is connected to the rotary spray assembly and atomizing spray gun through a slurry delivery pipeline.

[0005] Compared with existing technologies, this device optimizes the structure of the desulfurizer, setting it as a two-stage desulfurization system. In the first-stage desulfurization chamber, a Venturi mixing tube allows the flue gas entering from the inlet pipe to undergo initial aerosol mixing with lime slurry aerosol sprayed from the atomizing gun. This initial aerosol mixing performs the first stage of desulfurization. The reactants from this initial aerosol mixing escape from the upper end of the Venturi atomizing tube and distribute within the first-stage desulfurization chamber before entering the second-stage desulfurization chamber through a connecting hole. The rotating spray assembly in the second-stage desulfurization chamber can uniformly spray lime slurry aerosol over a wide area. This sprayed lime slurry effectively interacts with the initial flue gas entering the second-stage desulfurization chamber. The reactants undergo a second aerosol mixing, which allows for a second desulfurization treatment of the primary flue gas reactants. After two desulfurization treatments, the flue gas is effectively mixed with lime aerosol, improving the desulfurization effect. Simultaneously, the settling components in the secondary desulfurization chamber separate the secondary flue gas reactants, allowing lime particles to settle and reducing the particulate matter content. This reduces the filtration burden on the subsequent bag filter, preventing frequent clogging and effectively improving desulfurization efficiency. This device boasts advantages such as reasonable structure, stable operation, good desulfurization effect, and high desulfurization efficiency, making it easy to promote and use. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0007] Figure 2 This is a schematic diagram of the desulfurizer in this utility model;

[0008] Figure 3 This is a top view of the supporting component in this utility model;

[0009] In the diagram: 1-Lime slurry preparation tank, 2-Desulfurizer, 3-Bag filter, 4-Intermediate partition, 5-First-stage desulfurization chamber, 51-Venturi mixing pipe, 6-Second-stage desulfurization chamber, 61-Rotating pipe, 62-Atomizing pipe, 63-Spray pipe, 64-Rotating joint, 65-Venturi mixer, 66-Bend, 67-Nozzle, 68-Drive motor, 69-Driving pulley, 610-Driven pulley, 611-Transmission belt, 612-Guide rod, 613-Crossbar, 614-The second-stage desulfurization chamber. 615-Second clamping block, 616-First semicircular groove, 617-Second semicircular groove, 618-Connecting plate, 619-Stirring rod, 620-Stirring blade, 621-Settling cone, 622-Settling plate, 7-Ash collecting cone, 8-Ash discharge pipe, 9-Smoke inlet channel, 10-Atomizing spray gun, 11-Connecting hole, 12-Smoke guide pipe, 13-Exhaust pipe, 14-Exhaust fan, 15-Liquid outlet pipe, 16-Distribution pipe, 17-First liquid inlet pipe, 18-Second liquid inlet pipe. Detailed Implementation

[0010] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0011] like Figures 1-3As shown, this utility model includes a lime slurry preparation tank 1, a desulfurizer 2, and a bag filter 3. The lime slurry preparation tank 1 is a device used in the prior art, mainly used to prepare lime slurry by mixing quicklime powder and water according to a certain ratio. The bag filter 3 is a structure used in the prior art, mainly including dust collection bags, pulse-jet cleaning components, etc. The desulfurizer 2 has a vertically arranged intermediate partition 4 inside, which divides the inner cavity of the desulfurizer 2 into a primary desulfurization chamber 5 and a secondary desulfurization chamber 6. Each of the first-stage desulfurization chambers 5 has a dust collection cone 7 at its bottom, and a dust discharge pipe 8 at the bottom of the dust collection cone 7. A dust discharge valve is installed on the dust discharge pipe 8. A flue gas inlet channel 9 is provided through the lower part of the first-stage desulfurization chamber 5. One or two atomizing spray guns 10 are inclinedly installed at the upper part of the inlet end of the flue gas inlet channel 9. The atomizing spray gun 10 is a dual-fluid spray gun structure used in the prior art. Lime slurry enters the atomizing spray gun, and compressed air is input into the atomizing spray gun 10 through the air inlet on the atomizing spray gun 10. The lime slurry and compressed air flow from the atomizing spray gun... The lime slurry is atomized by the outlet of 10, increasing the contact between the lime slurry and the flue gas. A Venturi mixing pipe 51 is vertically installed inside the primary desulfurization chamber 5 via a support plate. The lower end of the Venturi mixing pipe 51 is connected to the flue gas inlet channel 9. The Venturi mixing pipe 51 is a structure used in the prior art, and its main function is to improve the atomization mixing effect of the flue gas and lime slurry. A rotating spray assembly is installed inside the secondary desulfurization chamber 6. A settling assembly is installed in the secondary desulfurization chamber 6 below the rotating spray assembly. A connecting hole 11 is provided on the middle partition plate 4 on the upper side of the settling component. A flue gas guide pipe 12 connected to the inlet of the bag filter 3 is provided on the secondary desulfurization chamber 6 on the lower side of the settling component. An exhaust pipe 13 is installed at the outlet of the bag filter 3. An induced draft fan 14 is installed on the exhaust pipe 13. The induced draft fan 14 is a structure used in the prior art. It mainly ensures that the flue gas flows evenly and stably between the desulfurizer 2 and the bag filter 3. The lime slurry preparation tank 1 is connected to the rotary spray component and the atomizing spray gun 10 through the slurry delivery pipeline.

[0012] The working process of this device is as follows: During use, the lime slurry prepared in the lime slurry preparation tank 1 enters the atomizing spray gun 10 and the rotating spray assembly through the slurry delivery pipeline. Under the action of the induced draft fan 14, the flue gas enters the smoke inlet channel 9, and the atomizing spray gun 10 sprays lime slurry into the smoke inlet channel 9. After the lime slurry is sprayed out from the atomizing spray gun, it forms lime slurry aerosol. The formed lime slurry aerosol and flue gas enter the Venturi mixing pipe 51, where the flue gas and lime slurry aerosol undergo the first mixing process. The aerosol mixing process allows for thorough contact between the flue gas and lime slurry aerosol, achieving the first stage of desulfurization. The first flue gas reactants, after the initial aerosol mixing, escape from the upper end of the Venturi atomizing tube 51 and distribute within the primary desulfurization chamber 5. As the first flue gas reactants flow downwards within the primary desulfurization chamber 5, the lime aerosol within them forms lime particles. These particles, under gravity, enter the ash collection cone 7 below the primary desulfurization chamber 5. The first flue gas reactants then enter the secondary desulfurization chamber 6 through the connecting hole 11. The rotating spray assembly within the secondary desulfurization chamber 6 can uniformly spray lime slurry aerosol over a wide area. This sprayed lime slurry aerosol performs a second aerosol mixing with the first flue gas reactants entering the secondary desulfurization chamber 6, achieving a second desulfurization treatment. The second flue gas reactants, generated after the second aerosol mixing, flow downwards and are settled by the settling assembly. After separation, the lime particles formed in the second flue gas reactants enter the ash collection cone 7 below the secondary desulfurization chamber 6 under gravity. The second flue gas reactants then enter the bag filter 3 through the flue gas guide pipe 12. After filtration and separation by the bag filter 3, the lime particles in the second flue gas reactants are separated again and fall to the bottom of the bag filter 6. The flue gas is discharged from the exhaust pipe 13 and enters the subsequent purification process. The lime particles in the ash collection cone 7 and the bottom of the bag filter 3 only need to be opened periodically. This device performs two desulfurization treatments on the flue gas, which not only effectively increases the contact time between the flue gas and the lime slurry, significantly improving the desulfurization efficiency, but also allows for sedimentation separation of the flue gas, causing the lime particles in the second flue gas reactants to settle, reducing the particulate matter content in the second flue gas reactants, reducing the filtration burden on the subsequent bag filter 3, and avoiding frequent clogging of the bag filter 3, thus effectively improving the desulfurization efficiency.

[0013] Furthermore, to ensure that the lime slurry in the lime slurry preparation tank 1 enters the atomizing spray gun 10 and the rotary spray assembly evenly and stably, the slurry delivery pipeline includes an outlet pipe 15 and a distribution pipe 16. One end of the outlet pipe 15 is connected to the bottom of the lime slurry preparation tank 1, and the other end is connected to the distribution pipe 16. Both ends of the distribution pipe 16 are sealed by end plates. The distribution pipe 16 is provided with a first inlet pipe 17 connected to the atomizing spray gun 10, and a second inlet pipe 18 connected to the rotary spray assembly. Both the first inlet pipe 17 and the second inlet pipe 18 are provided with inlet pumps and inlet valves. In use, the inlet pumps and inlet valves on the first inlet pipe 17 and the second inlet pipe 18 are opened, and the lime slurry in the lime slurry preparation tank 1 will enter the distribution pipe 16 through the outlet pipe 15, then enter the first inlet pipe 17 and the second inlet pipe 18, and finally enter the atomizing spray gun 10 and the rotary spray assembly.

[0014] Furthermore, to ensure that the rotary atomizing assembly can uniformly spray lime slurry into the secondary desulfurization chamber, the rotary atomizing assembly includes a rotating pipe 61, an atomizing pipe 62, and a spray pipe 63. The rotating pipe 61 is rotatably installed through the top of the secondary desulfurization chamber 6. A rotating joint 64 is installed at the upper end of the rotating pipe 61. The rotating joint 64 is a structure used in the prior art. One end of the atomizing pipe 62 is connected to the second liquid inlet pipe 18, and the other end of the atomizing pipe 62 is connected to the rotating joint 64. A Venturi mixer 65 is provided on the atomizing pipe 62, and a compressed air inlet is provided on the Venturi mixer 65. The lower end of the rotating pipe 61 is sealed by a base plate. Two bent pipes 66 are symmetrically arranged on both sides of the lower end of the rotating pipe 61. The upper end of the spray pipe 63 is connected to the bent pipes 66, and the lower end of the spray pipe 63 is sealed. Multiple nozzles 67 are evenly distributed along the axial direction on one side of the bent pipes 66 and the spray pipe 63. A pulley transmission mechanism connected to the rotating pipe 61 is provided at the top of the secondary desulfurization chamber 6. The pulley transmission mechanism includes a drive motor 68, a driving pulley 69, and a driven pulley 610. The drive motor 68 is a structure used in the prior art, and a finished product can be directly purchased according to the power required. The drive motor 68 is supported by a support. The support frame is installed on the top of the secondary desulfurization chamber 6. The driving pulley 69 is mounted on the output shaft of the drive motor 68, and the driven pulley 610 is mounted on the outer wall of the rotating tube 61. The driving pulley 69 and the driven pulley 610 are connected by a transmission belt 611. In use, the drive motor 68 drives the driving pulley 69 to rotate, which in turn drives the driven pulley 610 to rotate via the transmission belt 611. The rotation of the driven pulley 610 drives the rotating tube 61, which in turn drives the bend pipe 66, the spray pipe 63, and the nozzle 67 to rotate. At this time, the lime slurry entering through the atomizing pipe 62 enters the Venturi mixer. Inside the mixer 65, the Venturi mixer 65 is a structure used in the prior art. Its main purpose is to use compressed air to atomize lime slurry into a mist. After mixing with compressed air in the Venturi mixer 65, lime slurry mist is formed. The lime slurry mist enters the rotary joint 64, then enters the rotating bend pipe 66 and the spray pipe 63, and is then sprayed out through the nozzle 67. After being sprayed out by the rotating nozzle 67, the lime slurry mist can make full and uniform contact with the first flue gas reactants, so that they can react again to produce the second flue gas reactants, thereby performing a second desulfurization treatment on the first flue gas reactants.

[0015] Preferably, to ensure stable rotation of the spray pipe and prevent swaying during rotation, a clamping assembly is provided on the spray pipe 63. The clamping assembly includes a guide rod 612, a crossbar 613, a first clamping block 614, and a second clamping block 615. The guide rod 612 is vertically installed at the top of the secondary desulfurization chamber 6. The crossbar 613 is installed on the guide rod 612. One side of the first clamping block 614 is fixedly connected to the crossbar 613, and the other side of the first clamping block 614 is machined with a first semi-circular groove 616. The second clamping block 615 is symmetrically arranged with the first clamping block 614, and a groove is machined on one side of the second clamping block 615 closest to the first clamping block 614. The second semicircular groove 617, the first semicircular groove 616 and the second semicircular groove 617 combine to form a circular clamping cavity. The spray pipe 63 is slidably installed in the clamping cavity. Both ends of the first clamping block 614 and the second clamping block 615 are fixedly connected to connecting plates 618. The two connecting plates 618 are fixedly connected to each other by connecting bolts, clamping the spray pipe 63 between the first clamping block 614 and the second clamping block 615. Since the spray pipe 63 is slidably installed in the first semicircular groove 616 and the second semicircular groove 617, the rotation of the spray pipe 63 is within a relative space. This can avoid the phenomenon of the spray pipe 63 deviating during the rotation process and improve the stability of the rotation of the spray pipe 63.

[0016] Furthermore, to improve the mixing effect of the first flue gas reactants and lime slurry aerosol, a stirring rod 619 extending to the lower part of the secondary desulfurization chamber 6 is installed at the bottom of the base plate. The stirring rod 619 is equipped with multiple stirring blades 620. During the rotation of the rotating tube 61, the stirring rod 619 and stirring blades 620 can rotate synchronously. The rotating stirring rod 619 and stirring blades 620 can stir and mix the first flue gas reactants and lime slurry aerosol in the secondary desulfurization chamber 6, thereby improving the mixing effect of the first flue gas reactants and lime slurry aerosol and further improving the desulfurization effect.

[0017] Furthermore, to improve the separation effect of lime particles in the second flue gas reactants, the settling assembly includes a settling cone 621 and a settling plate 622. The settling cone 621 has a structure that is larger at the top and smaller at the bottom. The upper end of the settling cone 621 is fixedly connected to the inner wall of the secondary desulfurization chamber 6. The settling plate 622 is installed between the lower part of the settling cone 621 and the secondary desulfurization chamber 6. The settling plate 622 is evenly provided with multiple filter holes. The inlet of the flue gas guide pipe 12 is located between the settling plate 622 and the settling cone 621. In the secondary desulfurization chamber 6, as the second flue gas reactants flow downwards within the chamber, they are buffered and settled by the settling cone 621. The second flue gas reactants are then discharged from the bottom of the settling cone 621. After being separated and filtered by the settling plate 622, the lime particles in the second flue gas reactants settle into the ash collection cone 621 by gravity. The second flue gas reactants then enter the space above the settling plate 622 through the filter holes in the form of airflow, and then enter the bag filter through the flue gas pipe 12.

Claims

1. A desulfurization and dust removal device for a semi-dry flue gas desulfurization system, comprising a lime slurry preparation tank (1), a desulfurizer (2), and a bag filter (3), characterized in that: The desulfurizer (2) is vertically equipped with a middle partition (4), which divides the inner cavity of the desulfurizer (2) into a primary desulfurization chamber (5) and a secondary desulfurization chamber (6). Both the primary desulfurization chamber (5) and the secondary desulfurization chamber (6) have ash collection cones (7) at their bottoms. Ash discharge pipes (8) are installed at the bottom of the ash collection cones (7), and ash discharge valves are installed on the ash discharge pipes (8). A flue gas inlet channel (9) is installed through the lower part of the primary desulfurization chamber (5). One to two atomizing spray guns (10) are inclinedly installed at the upper part of the inlet end of the flue gas inlet channel (9). A Venturi mixing tube (51) is vertically installed inside the primary desulfurization chamber (5) via a support plate. The lower end of the Venturi mixing pipe (51) is connected to the flue gas inlet channel (9). The interior of the secondary desulfurization chamber (6) is equipped with a rotary spray assembly. The secondary desulfurization chamber (6) below the rotary spray assembly is equipped with a settling assembly. The middle partition plate (4) on the upper side of the settling assembly is equipped with a connecting hole (11). The secondary desulfurization chamber (6) below the settling assembly is equipped with a flue gas guide pipe (12) connected to the inlet of the bag filter (3). The outlet of the bag filter (3) is equipped with an exhaust pipe (13). The exhaust pipe (13) is equipped with an induced draft fan (14). The lime slurry preparation tank (1) is connected to the rotary spray assembly and the atomizing spray gun (10) through the slurry delivery pipeline.

2. A desulfurization and dust removal device of a semi-dry flue gas desulfurization system according to claim 1, characterized in that: The slurry delivery pipeline includes an outlet pipe (15) and a distribution pipe (16). One end of the outlet pipe (15) is connected to the bottom of the lime slurry preparation tank (1), and the other end is connected to the distribution pipe (16). Both ends of the distribution pipe (16) are sealed by end plates. A first inlet pipe (17) connected to the atomizing spray gun (10) is provided on the distribution pipe (16). A second inlet pipe (18) connected to the rotating spray assembly is provided on the distribution pipe (16). Both the first inlet pipe (17) and the second inlet pipe (18) are equipped with an inlet pump and an inlet valve.

3. A dust removal device for a semi-dry flue gas desulfurization system according to claim 2, characterized in that: The rotary atomizing assembly includes a rotating tube (61), an atomizing tube (62), and a spray tube (63). The rotating tube (61) is rotatably installed through the top of the secondary desulfurization chamber (6). A rotating joint (64) is installed at the upper end of the rotating tube (61). One end of the atomizing tube (62) is connected to the second liquid inlet pipe (18), and the other end of the atomizing tube (62) is connected to the rotating joint (64). A Venturi mixer (65) is provided on the atomizing tube (62). 5) A compressed air inlet is provided on the top. The lower end of the rotating pipe (61) is sealed by the bottom plate. Two bent pipes (66) are symmetrically arranged on both sides of the lower end of the rotating pipe (61). The upper end of the spray pipe (63) is connected to the bent pipe (66). The lower end of the spray pipe (63) is sealed. Multiple nozzles (67) are evenly distributed along the axial direction on one side of the bent pipe (66) and the spray pipe (63). The top of the secondary desulfurization chamber (6) is provided with a pulley transmission mechanism that is connected to the rotating pipe (61).

4. The desulfurization and dust removal device of the semi-dry flue gas desulfurization system according to claim 3, characterized in that: The pulley transmission mechanism includes a drive motor (68), a driving pulley (69), and a driven pulley (610). The drive motor (68) is mounted on the top of the secondary desulfurization chamber (6) via a support frame. The driving pulley (69) is mounted on the output shaft of the drive motor (68). The driven pulley (610) is mounted on the outer wall of the rotating tube (61). The driving pulley (69) and the driven pulley (610) are connected by a transmission belt (611).

5. The desulfurization and dust removal device for a semi-dry flue gas desulfurization system according to claim 3, characterized in that: A clamping assembly is provided on the spray pipe (63).

6. A dust removal device for a semi-dry flue gas desulfurization system according to claim 5, characterized in that: The clamping assembly includes a guide rod (612), a crossbar (613), a first clamping block (614), and a second clamping block (615). The guide rod (612) is vertically installed at the top of the secondary desulfurization chamber (6). The crossbar (613) is installed on the guide rod (612). One side of the first clamping block (614) is fixedly connected to the crossbar (613), and the other side of the first clamping block (614) is machined with a first semi-circular groove (616). The second clamping block (615) is connected to the first clamping block (614). 614) Symmetrically arranged, a second semi-circular groove (617) is machined on one side of the second clamping block (615) near the first clamping block (614). The first semi-circular groove (616) and the second semi-circular groove (617) are combined to form a circular clamping cavity. The spray pipe (63) is slidably installed in the clamping cavity. Both ends of the first clamping block (614) and the second clamping block (615) are fixedly connected to connecting plates (618). The two connecting plates (618) are fixedly connected to each other by connecting bolts.

7. A dust removal device for a semi-dry flue gas desulfurization system according to claim 3, characterized in that: The bottom of the base plate is equipped with a stirring rod (619) extending to the lower part of the secondary desulfurization chamber (6), and the stirring rod (619) is provided with a plurality of stirring blades (620).

8. The desulfurization and dust removal device for a semi-dry flue gas desulfurization system according to claim 1, characterized in that: The settling assembly includes a settling cone (621) and a settling plate (622). The settling cone (621) has a structure that is larger at the top and smaller at the bottom. The upper end of the settling cone (621) is fixedly connected to the inner wall of the secondary desulfurization chamber (6). The settling plate (622) is installed between the lower part of the settling cone (621) and the secondary desulfurization chamber (6). Multiple filter holes are evenly distributed on the settling plate (622). The inlet of the flue gas pipe (12) is located on the secondary desulfurization chamber (6) between the settling plate (622) and the settling cone (621).

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