A horizontal wet flue gas desulfurization system

Abstract

This invention provides a horizontal wet flue gas desulfurization system. The system includes a flue gas inlet, a flue gas outlet, and a desulfurization chamber fluidly communicating between the two. The horizontal flow direction of the flue gas within the desulfurization chamber is defined as a first direction. The desulfurization chamber includes a spray device for spraying desulfurization slurry and a gas-liquid dispersion plate inclined downwards in the first direction. The gas-liquid dispersion plate disperses the desulfurization slurry and flue gas to promote thorough mixing. A flue gas flow channel extending in the first direction is formed below the gas-liquid dispersion plate. The flue gas inlet is below the gas-liquid dispersion plate, and the flue gas outlet is above the gas-liquid dispersion plate. The gas-liquid dispersion plate is provided with multiple gas-liquid dispersion holes for upward penetration of the flue gas. In the first direction, the gas-liquid dispersion plate defines a high-resistance section near the flue gas inlet and a low-resistance section at its distal end away from the flue gas inlet. The low-resistance section has a larger opening ratio than the high-resistance section to guide the flue gas flow towards the distal end of the gas-liquid dispersion plate.

Description

Technical Field

[0001] This invention relates to the field of flue gas desulfurization technology, and in particular to a horizontal wet flue gas desulfurization system. Background Technology

[0002] Currently, the two most mature flue gas desulfurization technologies used in the electrolytic aluminum industry are traditional limestone-gypsum wet desulfurization and calcium hydroxide semi-dry desulfurization. Wet desulfurization is the mainstream technology in the electrolytic aluminum industry, its core being the efficient mass transfer between flue gas and desulfurization slurry. In existing technologies, spray towers are the most common reaction devices in wet desulfurization. They spray desulfurization slurry into the tower through nozzles located at the top, where it comes into counter-current contact with the flue gas flowing upwards to complete the desulfurization reaction. However, traditional spray towers have the following technical drawbacks: 1) Uneven flue gas distribution, with short-circuit flow or biased flow easily forming within the tower, resulting in insufficient slurry coverage in some areas and reducing overall desulfurization efficiency; 2) Poor droplet dispersion, with a wide droplet size distribution from the nozzles, making it difficult for larger droplets to fully contact the flue gas, thus limiting the mass transfer area; 3) Complex structure and high energy consumption. Some improved technologies use high-pressure nozzles or add multiple spray layers to improve gas-liquid contact, increasing system energy consumption and operating costs.

[0003] Therefore, it is necessary to propose a new technical solution to overcome the problems existing in the current technology. Summary of the Invention

[0004] This invention provides a horizontal wet flue gas desulfurization system that allows for more thorough gas-liquid contact, providing a new type of desulfurization system that is highly efficient and low-consumption in the field of wet desulfurization.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a horizontal wet flue gas desulfurization system, comprising a flue gas inlet disposed on one side, a flue gas outlet disposed on the other side, and a desulfurization chamber fluidly communicating the two, wherein the horizontal flow direction of the flue gas in the desulfurization chamber is defined as a first direction; the desulfurization chamber comprises:

[0006] A spraying device used for spraying desulfurization slurry;

[0007] A gas-liquid dispersion plate that is inclined downward in the first direction is used to disperse desulfurization slurry and flue gas to promote full mixing of the two. A flue gas flow channel extending in the first direction is formed below the gas-liquid dispersion plate. The flue gas inlet is disposed below the gas-liquid dispersion plate, and the flue gas outlet is disposed above the gas-liquid dispersion plate.

[0008] The gas-liquid dispersion plate is provided with a plurality of gas-liquid dispersion holes for the flue gas to pass through upward; and in the first direction, the gas-liquid dispersion plate defines a high smoke resistance section at the proximal end near the smoke inlet and a low smoke resistance section at the distal end away from the smoke inlet. The low smoke resistance section has a larger opening ratio than the high smoke resistance section, so as to guide the flue gas to flow towards the distal end of the gas-liquid dispersion plate.

[0009] Optionally, the gas-liquid dispersion plate has a plurality of gas-liquid dispersion units, and any one of the gas-liquid dispersion units disposed in the low smoke resistance section has a larger porosity than any one of the gas-liquid dispersion units disposed in the high smoke resistance section.

[0010] Optionally, the gas-liquid dispersion unit has multiple partitions arranged at intervals, with elongated gas-liquid dispersion holes formed between adjacent partitions.

[0011] Optionally, within the plane of the gas-liquid dispersion plate, the extension directions of the gas-liquid dispersion holes in two adjacent gas-liquid dispersion units are different.

[0012] Optionally, the gas-liquid dispersion holes are arranged at an upward angle, and the exhaust directions of the gas-liquid dispersion holes of two adjacent gas-liquid dispersion units are different, so as to form flue gas turbulence.

[0013] Optionally, the gas-liquid dispersion unit is rectangular, and the plurality of partitions are arranged in parallel along the diagonal of the rectangle.

[0014] Optionally, the multiple gas-liquid dispersion units configured in the low smoke resistance section have the same porosity, and the multiple gas-liquid dispersion units configured in the high smoke resistance section have the same porosity.

[0015] Optionally, the gas-liquid dispersion plate defines a medium-smoke resistance section between the high smoke resistance section and the low smoke resistance section, wherein the medium-smoke resistance section has a larger opening ratio than the high smoke resistance section and a smaller opening ratio than the low smoke resistance section.

[0016] Optionally, the medium smoke resistance section is configured as a plurality of sections, and the opening ratio of the plurality of medium smoke resistance sections increases in a gradient in the first direction.

[0017] Optionally, the porosity of the gas-liquid dispersion plate is set to gradually change from the high smoke resistance section to the low smoke resistance section.

[0018] Optionally, the horizontal wet flue gas desulfurization system includes a temperature and humidity control device installed at the flue gas inlet. The temperature and humidity control device sprays water mist onto the flue gas to reduce its temperature and increase its humidity.

[0019] Optionally, the average diameter of the water mist generated by the temperature and humidity control device is no greater than 30 μm, and the average diameter of the fine droplets dispersed by the desulfurization slurry is 70~200 μm.

[0020] Optionally, it also includes a dust removal and demisting device located in the desulfurization chamber, the dust removal and demisting device comprising multiple folding plates arranged at intervals, with tortuous channels formed between adjacent folding plates.

[0021] Optionally, it further includes a rinsing device comprising a plurality of rotating nozzles, the rotating nozzles being driven to rotate by liquid sprayed therefrom; wherein the rinsing device is disposed below the dust removal and demisting device to rinse the dust removal and demisting device, and / or, the rinsing device is disposed below the gas-liquid dispersion plate to rinse the gas-liquid dispersion plate.

[0022] Optionally, the folding plate has a smoke-facing surface and a smoke-repellent surface, and an airflow hole penetrating the smoke-facing surface and the smoke-repellent surface, wherein a few interfering flow protrusions are provided on the smoke-facing surface.

[0023] This invention innovatively proposes a technical solution for the synergistic effect of a gas-liquid dispersion plate and a flue gas flow channel. By optimizing the spatial variation structure of the flue gas flow channel and coordinating with the design of varying opening ratios of the gas-liquid dispersion holes, uniform distribution of flue gas is achieved without additional energy consumption. Simultaneously, the spraying device and the uniformly rising and sprayed flue gas form an impact-type dispersion mechanism, causing the desulfurization slurry droplets to form micron-sized droplets under the dual action of impact and airflow shearing. This significantly improves the gas-liquid contact interface area and mass transfer rate, providing a novel, highly efficient, and low-consumption reaction device for the field of wet desulfurization. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0025] Figure 1 This is a schematic diagram of an embodiment of the horizontal wet flue gas desulfurization system of the present invention.

[0026] Figure 2 This is a plan view of the gas-liquid dispersion plate in one embodiment of the horizontal wet flue gas desulfurization system of the present invention.

[0027] Figure 3 This is a partial perspective view of the gas-liquid dispersion plate in one embodiment of the horizontal wet flue gas desulfurization system of the present invention.

[0028] Figure 4 This is a partial side view of the gas-liquid dispersion holes of the gas-liquid dispersion plate in one embodiment of the horizontal wet flue gas desulfurization system of the present invention.

[0029] Figure 5 This is a partial side view of the dust removal and demisting device in one embodiment of the horizontal wet flue gas desulfurization system of the present invention.

[0030] Figure 6 This is a plan view of the dust removal and demisting device in one embodiment of the horizontal wet flue gas desulfurization system of the present invention.

[0031] Explanation of reference numerals in the attached drawings: 10, desulfurization chamber; 101, flue gas flow channel; 1, temperature and humidity control device; 2, gas-liquid dispersion plate; 201, partition plate; 202, gas-liquid dispersion hole; 21, high smoke resistance section; 22, medium smoke resistance section; 23, low smoke resistance section; 211, gas-liquid dispersion unit; 3, spray device; 4, flushing device; 5, dust removal and demisting device; 51, folding plate; 510, tortuous channel; 511, airflow hole; 512, turbulence protrusion; 6, desulfurization slurry pool; 7, circulating pump; 8, liquid replenishment device; L1 / L2, extension lines of gas-liquid dispersion holes. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] Unless otherwise defined, the technical or scientific terms used in this patent document shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this patent specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an," "a," or "the" do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" indicate that the element or object preceding "comprising" encompasses the element or object listed following "comprising" or its equivalents, and do not exclude other elements or objects. Terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are used only to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. These terms are only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, features in the following embodiments can be combined with each other.

[0037] Please see Figures 1 to 6 As shown, this invention provides a horizontal wet flue gas desulfurization system, which includes a flue gas inlet on one side, a flue gas outlet on the other side, and a desulfurization chamber 10 that fluidly connects the two. During the flow of flue gas from left to right within the desulfurization chamber 10, a portion of the flue gas flows upward through the gas-liquid dispersion plate 2, and the flue gas flow direction is as follows: Figure 1 As shown by the dashed arrow. The horizontal flow direction of the flue gas within the desulfurization chamber 10 is defined as the first direction, as shown below. Figure 1 and Figure 2As indicated by the solid arrow, the desulfurization chamber 10 includes a spray device 3 for spraying desulfurization slurry and a gas-liquid dispersion plate 2 inclined downwards in the first direction. The gas-liquid dispersion plate 2 disperses the desulfurization slurry and flue gas to promote thorough mixing. A flue gas flow channel 101 extending in the first direction is formed below the gas-liquid dispersion plate 2. The flue gas inlet is located below the gas-liquid dispersion plate 2, and the flue gas outlet is located above the gas-liquid dispersion plate 2. The gas-liquid dispersion plate 2 is provided with multiple gas-liquid dispersion holes 202 for upward penetration of flue gas. In the first direction, the gas-liquid dispersion plate 2 defines a high-resistance section 21 near the flue gas inlet and a low-resistance section 23 at its distal end away from the flue gas inlet. The low-resistance section 23 has a larger opening ratio than the high-resistance section 21 to guide the flue gas towards the distal end of the gas-liquid dispersion plate.

[0038] Specifically, the horizontal wet flue gas desulfurization system provided by this invention has a desulfurization chamber 10 in which flue gas and desulfurization slurry react to remove sulfur from the flue gas. The desulfurization chamber 10 has a gas-liquid dispersion plate 2 and a spray device 3. A flue gas flow channel 101 is formed below the gas-liquid dispersion plate 2 for the flue gas to enter and flow. The gas-liquid dispersion plate 2 has multiple gas-liquid dispersion holes 202 through which the flue gas in the flue gas flow channel 101 passes upward. The spray device 3 is arranged above the gas-liquid dispersion plate 2 for spraying desulfurization slurry onto the gas-liquid dispersion plate 2. From upstream to downstream in the flue gas entry direction, the space of the flue gas flow channel 101 decreases and the opening ratio of the gas-liquid dispersion holes 202 increases to guide the flue gas to a more distant location. The desulfurization slurry sprayed by the spraying device 3 can be dispersed into fine droplets by impact with the gas-liquid dispersion plate 2 and the flue gas passing through the gas-liquid dispersion plate 2, thereby increasing the contact area with the flue gas.

[0039] This invention innovatively proposes a technical solution for the synergistic effect of the gas-liquid dispersion plate 2 and the flue gas flow channel 101 with varying dimensions. By optimizing the spatial variation structure of the flue gas flow channel 101 and coordinating with the design of varying opening ratio of the gas-liquid dispersion holes 202, uniform distribution of flue gas can be achieved without additional energy consumption. At the same time, the spray device 3 and the uniformly rising and sprayed flue gas form an impact dispersion mechanism, causing the desulfurization slurry droplets to form micron-sized droplets under the dual action of impact and airflow shearing, significantly improving the gas-liquid contact interface area and mass transfer rate, providing a new type of highly efficient and low-consumption reaction device for the field of wet desulfurization.

[0040] Please see Figure 1 As shown, in a specific embodiment, the horizontal wet flue gas desulfurization system includes a desulfurization chamber 10, a temperature and humidity control device 1, a gas-liquid dispersion plate 2, a spray device 3, a flushing device 4, a dust removal and demisting device 5, a desulfurization slurry pool 6, a circulating pump 7, and a liquid replenishment device 8.

[0041] The desulfurization chamber 10 is the core area of ​​the desulfurization reaction, and it is equipped with the gas-liquid dispersion plate 2, spray device 3, flushing device 4, and dust removal and demisting device 5. The desulfurization chamber 10 has a flue gas inlet on the left side near the bottom and a flue gas outlet for the purified flue gas to be discharged on the right side near the top. The gas-liquid dispersion plate 2, spray device 3, flushing device 4, and dust removal and demisting device 5 are arranged roughly from bottom to top within the desulfurization chamber 10. The desulfurization chamber 10 can be constructed of metal plates, such as stainless steel plates, offering advantages such as no need for regular major repairs and low maintenance costs. In this embodiment, the desulfurization chamber 10 is horizontal, meaning it has a large lateral dimension and a small longitudinal dimension. Compared to traditional tall and narrow tower desulfurization equipment, this reduces the flow rate, increases the reaction time, improves desulfurization efficiency, reduces the liquid-to-gas ratio, reduces the circulating pump head, and reduces energy consumption.

[0042] The temperature and humidification device 1 is located at the flue gas inlet, that is, upstream of the flue gas flow channel 101, and is used to spray water mist onto the flue gas to reduce its temperature and increase its humidity. In this embodiment, the temperature and humidification device 1 is specifically an electromagnetic wave atomizing temperature and humidifier, which uses electromagnetic waves to atomize water. It is located in the area between the inlet of the desulfurization chamber 10 and its interior, about 5-6 meters away, so that the flue gas is cooled and humidified as it flows through this approximately 5-6 meters. Lowering the flue gas temperature by the temperature and humidification device 1 is beneficial for subsequent reactions, avoids scaling, reduces the outlet flue gas temperature, and reduces water consumption. Increasing the flue gas humidity by the temperature and humidification device 1 allows the sulfur dioxide in the flue gas to pre-react with water to generate sulfurous acid, thereby accelerating the subsequent reaction with limestone and increasing the reaction efficiency.

[0043] In this embodiment, the temperature-regulating and humidifying device 1 obtains clean water to generate water mist. The average diameter of the generated water mist is no greater than 30 μm, and preferably between 5 and 20 μm. This fine water mist can evaporate rapidly, absorb heat from the flue gas, reduce the flue gas temperature, and increase the humidity of the flue gas, creating favorable conditions for subsequent desulfurization reactions. It should be further noted that the average diameter of the water mist generated by the temperature-regulating and humidifying device 1 is smaller than the average diameter of the fine droplets dispersed from the desulfurization slurry. In other words, although one of the core aspects of this invention is the dispersion of the desulfurization slurry, the average diameter of the fine droplets dispersed from the desulfurization slurry in this invention is far less than that of the water mist formed by commonly used atomization methods such as electromagnetic atomization. This invention does not use traditional atomization methods to atomize the desulfurization slurry because the dissolved calcium carbonate in the slurry is typically required to be below 200 mesh, i.e., its diameter is approximately 74 μm. If traditional atomization methods are used, droplets with a diameter of approximately 10 μm can be formed. This causes the water in the desulfurization slurry to be atomized, resulting in the separation of dissolved calcium carbonate from the water. Consequently, solid particles (such as calcium carbonate) in the desulfurization slurry are prone to depositing in the atomizer pipes and nozzles, leading to blockages. This necessitates periodic shutdowns for cleaning, affecting continuous production and shortening the atomizer's lifespan. Furthermore, the high viscosity of the slurry and uneven atomization can easily cause equipment malfunctions. After water is atomized, the desulfurizing agent becomes locally concentrated, easily leading to scaling. The desulfurization slurry treated using one embodiment of this invention disperses into fine droplets with an average diameter between 70 and 200 μm, preferably between 100 and 200 μm. Droplets within this size range exhibit better mass transfer performance and can fully contact and react with the flue gas.

[0044] Please continue reading Figure 1 As shown, the gas-liquid dispersion plate 2 is located in the middle or lower part of the desulfurization chamber 10, and has a gap between it and the bottom wall of the desulfurization chamber 10, so as to form the flue gas flow channel 101 below the gas-liquid dispersion plate 2. The gas-liquid dispersion plate 2 has a plurality of gas-liquid dispersion holes 202 that penetrate vertically through the gas-liquid dispersion plate 2, so that the flue gas in the flue gas flow channel 101 passes upward through the gas-liquid dispersion plate 2 and flows into the space between the spray device 3 and the gas-liquid dispersion plate 2.

[0045] The spraying device 3 is arranged above the gas-liquid dispersion plate 2 and has a gap between it and the gas-liquid dispersion plate 2. The spraying device 3 is used to spray desulfurization slurry onto the gas-liquid dispersion plate 2. The nozzle design of the spraying device 3 is optimized to ensure that the desulfurization slurry can uniformly cover the surface of the gas-liquid dispersion plate 2. The spraying device 3 adopts a multi-nozzle design, and the arrangement of the nozzles and the spraying intensity are precisely calculated to ensure that the desulfurization slurry can be uniformly sprayed onto all areas of the gas-liquid dispersion plate 2. The desulfurization slurry sprayed from the spraying device 3 is uniformly dispersed into fine droplets by impact with the gas-liquid dispersion plate 2 and the impact of the flue gas passing through the gas-liquid dispersion plate 2.

[0046] In one embodiment, the flushing device 4 is arranged above the spraying device 3. In this embodiment, the flushing device 4 includes several rotating nozzles for flushing the inner wall of the desulfurization chamber 10 and the dust removal and demisting device 5. The rotating nozzles of the flushing device 4 are driven to rotate by the liquid sprayed from them, achieving uniform flushing of the inner wall of the desulfurization chamber 10 and the dust removal and demisting device 5. This increases the flushing area of ​​each nozzle without increasing energy consumption, reduces the number of nozzles, and optimizes the flushing effect. The flushing water can come from a dedicated flushing water system. Regularly flushing the inner wall of the desulfurization chamber 10 and the dust removal and demisting device 5 by the flushing device 4 can remove dust and impurities adhering to their surfaces, keeping the system clean and operating efficiently. The dust removal and demisting device 5 is located below the flue gas outlet at the top of the desulfurization chamber 10 and is used to remove dust particles and mist droplets from the purified flue gas. In another embodiment, the rinsing device 4 is disposed below the gas-liquid dispersion plate 2 to rinse the gas-liquid dispersion plate 2, thereby removing dust and impurities adhering to the gas-liquid dispersion plate 2 and maintaining the cleanliness and efficient operation of the system.

[0047] Please refer to the following: Figure 5 and Figure 6 As shown, the dust removal and demisting device 5 includes multiple tortuous channels 510 with zigzag flow. These tortuous channels 510 can be S-shaped, <-shaped, etc., from bottom to top. Dust particles and water mist in the flue gas are blocked by these tortuous channels 510, thereby reducing the amount of dust particles and mist droplets in the flue gas discharged from the flue gas outlet. Further, the dust removal and demisting device 5 includes multiple spaced-apart folding plates 51, with the tortuous channels 510 formed between adjacent folding plates 51. Each folding plate 51 has a smoke-facing surface and a smoke-repelling surface, and airflow holes 511 penetrating the smoke-facing surface and the smoke-repelling surface. In this embodiment, the folding plate 51 is <-shaped, including an upper plate and a lower plate. Since the flue gas flows from bottom to top, the outer surface of the lower plate and the inner surface of the upper plate are the surfaces that the rising flue gas can directly impact, i.e., the smoke-facing surface. The inner surface of the lower plate and the outer surface of the upper plate are the smoke-repelling surface. Several turbulent flow protrusions 512 are provided on the smoke-facing surface. The turbulence protrusions 512 and airflow holes 511 are arranged at intervals. When the smoke collides with the smoke-facing surface, part of the smoke flows along the surface of the baffle 51, while part of the smoke enters the adjacent tortuous channel 510 through the airflow holes 511. During this process, the smoke comes into contact with the turbulence protrusions 512 and is disturbed to form multiple small eddies, which effectively condenses and agglomerates dust and water mist and removes them.

[0048] Furthermore, droplet coagulation and low-resistance dust and fog removal can be achieved through particulate trajectory tracking and eddy current control. Specifically, the trajectory of particles in the airflow is tracked using a high-resolution microscope and a high-frame-rate high-speed camera under a special lighting system to understand the particle motion within the airflow. Then, based on the experimental data, a mathematical model is established using numerical simulation to describe the interaction forces between particles and the interaction between particles and the airflow. This yields the particle trajectory in the complex flow field. The calculated trajectory is compared with the observed actual particle trajectory to optimize the calculation model and improve the accuracy and reliability of the simulation. Based on the trajectory tracking calculation, the hierarchical transmission control of eddies at different scales is further studied, including analyzing the characteristics of eddies in the flow field and designing appropriate control strategies to achieve precise control of droplets and dust. Based on this, the coagulation and aggregation of fine droplets and dust particles are controlled to achieve efficient dust and fog removal.

[0049] Please continue reading Figure 1 As shown, the desulfurization slurry tank 6 is used to store desulfurization slurry, which is also the desulfurizing agent. In this embodiment, it is limestone slurry. The desulfurization slurry is transported to the spraying device 3 by a circulating pump 7. The circulating pump 7 provides circulation power for the desulfurization slurry. In this embodiment, two circulating pumps 7 are provided, which can work simultaneously or selectively as needed to deliver desulfurization slurry to the spraying device 3. In other embodiments, one or more circulating pumps 7 may be provided. The replenishment device 8 is used to replenish fresh desulfurization slurry to the desulfurization slurry tank 6, and it may specifically include replenishment pipelines, replenishment tanks, etc.

[0050] Please refer to this carefully. Figure 2 and Figure 3 As shown, the gas-liquid dispersion plate 2 is one of the core components of this invention, and its top-view structural schematic diagram is shown below. Figure 2 As shown, a partial structural diagram from a three-dimensional perspective is as follows: Figure 3 As shown. Please refer to the following: Figure 1 As shown, the gas-liquid dispersion plate 2 is generally rectangular in shape and is arranged at a downward inclination in the first direction, that is, from upstream to downstream of the flue gas inlet direction. This arrangement causes the space of the flue gas flow channel 101 to be reduced in the first direction. That is, if the flue gas inlet direction is taken as the length direction of the flue gas flow channel 101, then in this embodiment, the width of the flue gas flow channel 101 remains unchanged, while the height gradually decreases due to the inclination of the gas-liquid dispersion plate 2, thus reducing the space of the flue gas flow channel 101. In this embodiment, the space of the flue gas flow channel 101 is continuously and gradually reduced; in other embodiments, the flue gas flow channel 101 can also be configured to shrink abruptly in a gradient manner.

[0051] Please see Figures 2 to 4 As shown, the gas-liquid dispersion plate 2 has multiple gas-liquid dispersion holes 202. Furthermore, in the first direction, the gas-liquid dispersion plate 2 defines a high-resistance section 21 near the smoke inlet and a low-resistance section 23 far from the smoke inlet. The low-resistance section 23 has a larger opening ratio than the high-resistance section 21. Since the kinetic energy of the flue gas weakens from upstream to downstream in the first direction (i.e., from the horizontal direction of flue gas entry), if the gas-liquid dispersion holes 202 on the gas-liquid dispersion plate 2 and the flue gas flow channel 101 are uniformly arranged, most of the flue gas will pass through the gas-liquid dispersion plate 2 from the upstream, while the portion of the gas-liquid dispersion plate 2 near the downstream will have less or no flue gas passing through, resulting in a flow deviation phenomenon. In the first direction, the present invention reduces the space of the flue gas passage 101 and increases the opening ratio of the gas-liquid dispersion holes 202 to balance the pressure of the flue gas and distribute a portion of the flue gas downstream, thereby promoting more uniform passage of the flue gas through each area of ​​the gas-liquid dispersion plate 2.

[0052] In this embodiment, specifically, the gas-liquid dispersion plate 2 sequentially defines multiple segments in the first direction, such as a high smoke resistance segment 21, a medium smoke resistance segment 22, and a low smoke resistance segment 23. The downstream segment has a higher open area ratio than the upstream segment. That is, in this embodiment, the medium smoke resistance segment 22 has a larger open area ratio than the high smoke resistance segment 21, and the low smoke resistance segment 23 has a smaller open area ratio. It is understood that this embodiment uses three segments as an example for illustration; however, in other embodiments, the segments can be two, four, or more. In other words, in other embodiments, the medium smoke resistance segment 22 may be absent, or multiple medium smoke resistance segments 22 may be configured. For embodiments with multiple medium smoke resistance segments 22, further, in the first direction, the open area ratios of the multiple medium smoke resistance segments 22 increase in a gradient. Additionally, it should be noted that in some embodiments, the porosity of the gas-liquid dispersion plate 2 can be continuously and gradually changed from the high smoke resistance section 21 to the low smoke resistance section 23, that is, the porosity is continuously and gradually increased.

[0053] Furthermore, each section also includes multiple gas-liquid dispersion units. Figure 2Only a few gas-liquid dispersion units within the high-resistance section 21 are exemplarily indicated, designated as 211. It can be understood that each section includes multiple gas-liquid dispersion units. Any gas-liquid dispersion unit configured in the low-resistance section 23 has a larger porosity than any gas-liquid dispersion unit configured in the high-resistance section. The gas-liquid dispersion holes 202 within adjacent gas-liquid dispersion units in the same section extend in different directions from bottom to top, and the porosity of multiple gas-liquid dispersion units within the same section is the same. That is, the porosity of multiple gas-liquid dispersion units configured in the low-resistance section 23 is the same, and the porosity of multiple gas-liquid dispersion units configured in the high-resistance section 21 is the same. This arrangement ensures that the amount of flue gas passing through two adjacent gas-liquid dispersion units is approximately equal, but in different directions, thereby forming two airflows with equal kinetic energy that can collide with each other, exerting an impact and shearing effect on the desulfurization slurry to form dispersed fine droplets. Specifically, in some embodiments, two adjacent gas-liquid dispersion units exist within the same section, with the upward extension lines of their gas-liquid dispersion holes 202 intersecting directly above the dividing line between the two gas-liquid dispersion units; thus, two adjacent airflows collide. In other embodiments, four adjacent gas-liquid dispersion units exist within the same section in a grid pattern, with the upward extension lines of their gas-liquid dispersion holes 202 intersecting directly above the intersection point of the four gas-liquid dispersion units; thus, four airflows collide. These designs also generate turbulence in the flue gas as it passes through the gas-liquid dispersion plate 2, further promoting the mixing of the flue gas and the desulfurization slurry and improving desulfurization efficiency.

[0054] In this embodiment, the gas-liquid dispersion unit has multiple spaced partitions 201, with elongated gas-liquid dispersion holes 202 formed between adjacent partitions 201. Within the plane of the gas-liquid dispersion plates 201, the extending directions of the gas-liquid dispersion holes 202 in adjacent gas-liquid dispersion units are different. The gas-liquid dispersion holes 202 are arranged at an upward inclination, and the exhaust directions of the gas-liquid dispersion holes 202 in adjacent gas-liquid dispersion units are different, thus creating turbulent flue gas flow. Specifically, as... Figure 3 and Figure 4 As shown, the gas-liquid dispersion plate 2 includes multiple partitions 201, with gas-liquid dispersion holes 202 formed between adjacent partitions 201. The inclination angle and spacing of the partitions 201 are optimized to ensure uniform distribution of flue gas within the flue gas flow channel 101 and to promote the flue gas to pass through the gas-liquid dispersion holes 202 at a suitable velocity. The extension lines of the gas-liquid dispersion holes 202 in two adjacent gas-liquid dispersion units within the same section are shown below. Figure 4As shown, L1 and L2 intersect at point O above the gas-liquid dispersion plate 2, causing an impact. This impact disperses the desulfurization slurry and creates turbulence in the flue gas, increasing the gas-liquid contact mass transfer effect. In this embodiment, the angle between the upper and lower surfaces of the partition plate 201 and the gas-liquid dispersion plate 2 is between 20° and 40°. This avoids an angle that is too small, making it difficult for the flue gas to pass through; and at the same time, it avoids an angle that is too large, causing the flue gas passing through the gas-liquid dispersion holes 202 to fail to intersect and impact each other in the space between the spray device 3 and the gas-liquid dispersion plate 2, or causing the impact position to be too far away from the gas-liquid dispersion plate 2, thus weakening the impact effect.

[0055] In use, the flue gas desulfurization system provided by this invention introduces flue gas generated in the electrolytic aluminum industry through an inlet into the flue gas flow channel 101 at the bottom of the desulfurization chamber 10. During the process of entering the flue gas flow channel 101, the flue gas is cooled and humidified by the temperature and humidity control device 1, which is beneficial to the subsequent reaction. Due to the special flue gas flow channel 101 structure and the special gas-liquid dispersion holes 202 on the gas-liquid dispersion plate 2, the pressure distribution of the flue gas from upstream to downstream is more uniform than that of the traditional structure. After being uniformly distributed, the flue gas rises through the gas-liquid dispersion plate 2. The dispersion hole 202 prevents flue gas from flowing out of the system. The spray device 3 sprays desulfurization slurry onto the gas-liquid dispersion plate 2. The desulfurization slurry is evenly dispersed into fine droplets by impact with the gas-liquid dispersion plate 2 and by the impact of the flue gas passing through the gas-liquid dispersion plate 2. The dispersed desulfurization slurry droplets come into full contact with the flue gas in the area above the gas-liquid dispersion plate 2, and a desulfurization reaction occurs. The alkaline substances such as calcium carbonate in the droplets react with the acidic gases such as sulfur dioxide in the flue gas to produce products such as sulfates. The purified flue gas after the reaction flows upward and, after the dust removal and demisting device 5 removes dust particles and mist droplets, it is discharged through the purified flue gas outlet at the top of the desulfurization chamber 10. At the same time, the unreacted desulfurization slurry flows back to the desulfurization slurry pool 6 from the bottom of the desulfurization chamber 10 through the circulation pump 7 for recycling. The liquid replenishment device 8 replenishes the desulfurization slurry pool 6 with fresh desulfurization slurry to maintain the stable operation of the system.

[0056] As can be seen from the above description of the specific embodiments, the horizontal wet flue gas desulfurization system provided by the present invention adopts a horizontal reactor, which can reduce the flow rate, increase the reaction time, improve the desulfurization efficiency, reduce the liquid-to-gas ratio, reduce the circulating pump head, reduce energy consumption, and has a low height and compact structure, making it easy to install and maintain. The flue gas is pretreated by the temperature and humidity control device 1, which reduces the flue gas temperature and increases the humidity, thereby improving the stability and reliability of the system and increasing the subsequent reaction speed. The desulfurization slurry is broken up by airflow collision, which reduces the droplet size and increases the specific surface area. The flue gas turbulence caused by airflow collision further promotes gas-liquid mixing, and the airflow breaks the liquid film of the calcium carbonate slurry, increasing the reaction efficiency. The flue gas flow channel 101 below the gas-liquid dispersion plate 2 is set with a reduced space, and the opening ratio of the gas-liquid dispersion holes 202 is set with an increased space, which promotes the flue gas to pass through the gas-liquid dispersion plate 2 evenly and avoids the phenomenon of flue gas deviation.

[0057] As a wet desulfurization technology, the desulfurization system provided by this invention, compared with the traditional limestone-gypsum wet desulfurization system, firstly adopts a horizontal desulfurization chamber, upgrading the traditional vertical desulfurization tower into a horizontal desulfurization reaction device to change the internal flow field and create conditions for achieving ultrafine droplets; secondly, droplet dispersion and refinement are carried out in wet desulfurization, reducing the droplet size of the desulfurizing agent from 2000~2500μm in traditional desulfurization to 100~200μm, improving diffusion mass transfer efficiency and reducing the liquid-gas ratio.

[0058] In a test project using the horizontal wet flue gas desulfurization system provided by this invention, the emission concentration of sulfur dioxide in the flue gas emitted at the flue gas outlet was found to be less than 20 mg / Nm³. 3 The outlet emission concentration of particulate matter is less than 5 mg / Nm³. 3 The outlet emission concentration of fluoride is less than 0.1 mg / Nm³. 3 It is far superior to the requirements for Class A enterprises in the Amendment to the Emission Standard for Pollutants in Aluminum Industry (GB 25465-2010) and the Technical Guidelines for the Formulation of Emergency Emission Reduction Measures for Key Industries in Heavy Pollution Weather. It effectively improves the electrolysis workshop and its surrounding environment, reduces the harm of electrolysis production to workers and surrounding agriculture and animal husbandry, and has good social benefits.

[0059] Calculations of operational efficiency show that, regarding power consumption, the traditional limestone-gypsum wet desulfurization system consumes approximately 80-110 kW•h / t-Al (kilowatt-hours per ton of aluminum), while the calcium hydroxide semi-dry desulfurization system consumes approximately 110-140 kW•h / t-Al. In contrast, the desulfurization system using this invention consumes ≤55 kW•h / t-Al, saving over 25 kW•h / t-Al compared to the traditional wet method. If adopted across the entire industry, it could save at least 1.1 billion kW•h of electricity annually, equivalent to 189,000 tons of standard coal, and reduce carbon dioxide emissions by 1.1 million tons. Therefore, the desulfurization system using this invention demonstrates significant power savings, responds to the national "dual-carbon policy," effectively reduces the comprehensive AC power consumption of molten aluminum in electrolytic aluminum production, and provides a technical solution to meet the tiered standards stipulated in the "Notice of the National Development and Reform Commission on Improving the Tiered Electricity Pricing Policy for the Electrolytic Aluminum Industry."

[0060] Regarding water consumption, the desulfurization system using this invention has water consumption comparable to that of limestone-gypsum wet desulfurization, with an actual water consumption of 1.21 m³ / s. 3 / t-Al (cubic meters per ton of aluminum); semi-dry desulfurization consumes less water, approximately 0.6m³. 3 / t-Al. Water fee is 2.23 yuan / m³. 3 Calculations show that the water cost of this invention is the same as that of the limestone-gypsum method, but the water cost increases by 1.36 yuan / t-Al compared to the calcium hydroxide semi-dry method.

[0061] Regarding desulfurizing agent consumption, the desulfurization system of this invention consumes approximately the same amount of desulfurizing agent as the traditional wet desulfurization method. According to actual operational measurements, the limestone consumption per ton of aluminum is 23.94 kg / t-Al, while the semi-dry desulfurizing agent, calcium hydroxide, consumes 36.48 kg / t-Al. Calculated at 600 yuan / t for calcium hydroxide and 301.6 yuan / t for limestone, the desulfurizing agent cost of this technology is the same as that of the traditional wet desulfurization method. Compared with the calcium hydroxide semi-dry method, this technology saves 997,400 yuan in desulfurizing agent costs annually: (36.48*600-23.94*301.6) / 1000*6.8 = 997,400 yuan.

[0062] The desulfurization system of this invention and traditional wet desulfurization technology produce gypsum as the desulfurization product, which meets the Class III standard of "Flue Gas Desulfurization Gypsum" (GB / T 37785-2019). This gypsum can be sent to relevant manufacturers for gypsum board or cement aggregate without additional processing costs. In contrast, the desulfurization product of the calcium hydroxide semi-dry method is a mixture of calcium oxide, calcium hydroxide, calcium sulfite, and gypsum, which is solid waste with a processing cost of approximately 100 yuan / t. The semi-dry method produces approximately 60.13 kg / t-Al of desulfurization products per ton of aluminum. Therefore, compared with traditional wet desulfurization technology, the processing cost of the desulfurization products is the same. Compared with the calcium hydroxide semi-dry method, this technology saves 100*60.13*6.8 / 1000=408,900 yuan annually in desulfurization product processing costs.

[0063] Furthermore, the desulfurization chamber of the desulfurization system of this invention is mainly made of 2205 stainless steel, requiring no regular major overhauls and resulting in low maintenance costs of approximately 3 yuan / t-A1. Traditional vertical tower wet desulfurization systems require regular major overhauls and replacement of anti-corrosion coatings, leading to high maintenance costs of approximately 9 yuan / t-A1; while calcium hydroxide semi-dry desulfurization requires frequent replacement of filter bags, resulting in high daily maintenance and costs of approximately 6 yuan / t-A1. Therefore, based on an annual electrolytic aluminum production of 68,000 tons, the maintenance cost of the desulfurization system of this invention is (9-3)*6.8=408,000 yuan per year compared to traditional wet desulfurization; and (6-3)*6.8=204,000 yuan per year compared to calcium hydroxide semi-dry desulfurization.

[0064] Furthermore, vertical towers require annual overhauls and replacements to prevent corrosion, and according to environmental requirements, two towers should be installed, one for operation and one for backup, resulting in high investment costs. Moreover, during operation, valves cannot be completely sealed, allowing a small amount of flue gas to enter the backup tower. This small amount of flue gas cools quickly, easily dropping below the dew point, often leading to damage to the backup tower before it is even used. The desulfurization system of this invention, whose reaction devices are primarily made of 2205 stainless steel, does not require annual overhauls, significantly reducing maintenance workload. Furthermore, when using the desulfurization system of this invention, two reaction devices can be used simultaneously. When one reaction device requires maintenance, all flue gas can be treated through the other reaction device. Although the effect of flue gas treated by only one reaction device is not as good as that of two devices treating simultaneously, it still meets environmental standards.

[0065] Furthermore, since the desulfurization system is installed between two or more aluminum electrolysis workshops, which have very high magnetic fields, welding work in such an environment is extremely difficult. Therefore, the desulfurization system of this invention adopts a modular design. The main components of the desulfurization system, such as the shell forming the desulfurization chamber 10, are pre-welded into modular whole components before being transported to the installation site. After delivery to the installation site, the components are assembled primarily through hoisting or other methods. This significantly reduces the welding work required near the electrolysis workshops, lowers the welding difficulty, and shortens the construction period of the desulfurization system.

[0066] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A horizontal wet flue gas desulfurization system, comprising a flue gas inlet disposed on one side, a flue gas outlet disposed on the other side, and a desulfurization chamber fluidly communicating the two, wherein the horizontal flow direction of the flue gas within the desulfurization chamber is defined as a first direction; characterized in that, The desulfurization chamber is equipped with: A spraying device used for spraying desulfurization slurry; A gas-liquid dispersion plate that is inclined downward in the first direction is used to disperse desulfurization slurry and flue gas to promote full mixing of the two. A flue gas flow channel extending in the first direction is formed below the gas-liquid dispersion plate. The flue gas inlet is disposed below the gas-liquid dispersion plate, and the flue gas outlet is disposed above the gas-liquid dispersion plate. The gas-liquid dispersion plate has multiple gas-liquid dispersion units, each containing multiple spaced baffles. Elongated gas-liquid dispersion holes are formed between adjacent baffles, allowing flue gas to pass upwards. In the first direction, the gas-liquid dispersion plate defines a high-resistance section containing multiple gas-liquid dispersion units at its proximal end near the flue gas inlet and a low-resistance section containing multiple gas-liquid dispersion units at its distal end away from the flue gas inlet. The low-resistance section has a larger opening ratio than the high-resistance section, guiding the flue gas towards the distal end of the gas-liquid dispersion plate. Within the same section, two adjacent gas-liquid dispersion units have their upward-extending gas-liquid dispersion holes intersecting directly above the dividing line between the two units. And / or, within the same section, four adjacent gas-liquid dispersion units are arranged in a grid pattern, with their upward-extending gas-liquid dispersion holes intersecting directly above the intersection point of the four units, causing airflow collisions to form flue gas turbulence.

2. The horizontal wet flue gas desulfurization system as described in claim 1, characterized in that, The gas-liquid dispersion unit is rectangular, and the plurality of partitions are arranged in parallel along the diagonal of the rectangle.

3. The horizontal wet flue gas desulfurization system as described in claim 1 or 2, characterized in that, The multiple gas-liquid dispersion units configured in the low smoke resistance zone have the same porosity, and the multiple gas-liquid dispersion units configured in the high smoke resistance zone have the same porosity.

4. The horizontal wet flue gas desulfurization system as described in claim 1 or 2, characterized in that, The gas-liquid dispersion plate defines a medium smoke resistance section between the high smoke resistance section and the low smoke resistance section. The medium smoke resistance section has a larger opening ratio than the high smoke resistance section and a smaller opening ratio than the low smoke resistance section.

5. The horizontal wet flue gas desulfurization system as described in claim 4, characterized in that, The medium smoke resistance zone is configured as a plurality of such zones, and the opening ratio of the plurality of medium smoke resistance zones increases in a gradient in the first direction.

6. The horizontal wet flue gas desulfurization system as described in claim 1 or 2, characterized in that, The porosity of the gas-liquid dispersion plate is set to gradually change from the high smoke resistance section to the low smoke resistance section.

7. The horizontal wet flue gas desulfurization system as described in claim 1 or 2, characterized in that, The horizontal wet flue gas desulfurization system includes a temperature and humidity control device installed at the flue gas inlet. The temperature and humidity control device sprays water mist onto the flue gas to reduce its temperature and increase its humidity.

8. The horizontal wet flue gas desulfurization system as described in claim 7, characterized in that, The average diameter of the water mist generated by the temperature and humidity control device is no greater than 30 μm, and the average diameter of the fine droplets dispersed by the desulfurization slurry is 70~200 μm.

9. The horizontal wet flue gas desulfurization system as described in claim 1 or 2, characterized in that, It also includes a dust removal and demisting device installed in the desulfurization chamber, the dust removal and demisting device comprising multiple folding plates arranged at intervals, with tortuous channels formed between adjacent folding plates.

10. The horizontal wet flue gas desulfurization system as described in claim 9, characterized in that, The folding plate has a smoke-facing surface and a smoke-repellent surface, and an airflow hole penetrating the smoke-facing surface and the smoke-repellent surface, wherein a few turbulent flow protrusions are provided on the smoke-facing surface.

11. The horizontal wet flue gas desulfurization system as described in claim 9, characterized in that, It also includes a rinsing device comprising a plurality of rotating nozzles, the rotating nozzles being driven to rotate by liquid sprayed from them; wherein the rinsing device is disposed below the dust removal and demisting device to rinse the dust removal and demisting device, and / or, the rinsing device is disposed below the gas-liquid dispersion plate to rinse the gas-liquid dispersion plate.

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