Limestone-gypsum wet flue gas desulfurization process

Abstract

The invention discloses a limestone-gypsum wet flue gas desulfurization process, and belongs to the technical field of flue gas desulfurization, the limestone-gypsum wet flue gas desulfurization process comprises a desulfurization tower, a rotary atomization structure and a flue gas pipeline, and the interior of the desulfurization tower is sequentially composed of a flue gas emission area, a demisting area, a spraying area, a rotary atomization area and a slurry oxidation area; the flue gas desulfurization process comprises the following steps: S1, flue gas is conveyed into a desulfurization tower through a flue gas pipeline and flows upwards; s2, the limestone absorption liquid forms first fog drops and second fog drops in the spraying area and the rotary atomization area respectively and makes contact with the flue gas; s3, desulfurized flue gas is formed after flue gas desulfurization, passes through a demisting area and then is discharged out of the desulfurization tower from a flue gas discharge area; s4, forming absorption slurry after the limestone absorption liquid absorbs sulfur dioxide, dripping the absorption slurry into a slurry oxidation area, carrying out forced oxidation, and preparing gypsum; according to the flue gas desulfurization process, the flue gas is in full contact with the limestone absorption liquid, so that the flue gas desulfurization rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas desulfurization, and in particular to a limestone-gypsum wet flue gas desulfurization process. Background Art

[0002] Industrial production in the fields of energy, metallurgy, chemical industry, etc. usually produces flue gas containing sulfur dioxide, which is the main factor causing acid rain. In order to make industrial production meet the requirements of energy conservation and emission reduction, it is usually necessary to remove sulfur dioxide from the flue gas before discharging it into the atmosphere. There are three types of flue gas sulfur dioxide purification technologies: dry, semi-dry and wet. Wet desulfurization has the advantages of high desulfurization rate, reliable equipment operation and simple operation. It is the current mainstream flue gas desulfurization technology. Among them, the more reliable one is the limestone-gypsum desulfurization method. Although limestone slurry can effectively absorb sulfur dioxide in flue gas, some flue gas desulfurization processes do not pay attention to the contact efficiency between limestone slurry and flue gas, resulting in a high proportion of sulfur dioxide remaining in the flue gas and being discharged into the atmosphere, causing damage to the atmospheric environment.

[0003] Based on the above situation, a Chinese patent with publication (announcement) number CN101716461A discloses a method for improving the desulfurization efficiency of a flue gas limestone-gypsum wet desulfurization process, the steps of which include: setting up a lime slurry process in a desulfurization island, adding water to the slaked lime to prepare lime milk with a mass percentage of 20% to 25%, then adding the lime milk to the limestone slurry to prepare a lime milk-limestone mixed slurry, and the prepared mixed slurry enters an absorption tower for desulfurization; when the sulfur dioxide concentration is high, the lime milk slurry can directly enter the mixed slurry circulating oxidation tank, which can quickly stabilize the pH value in the slurry; the ratio of lime milk to limestone in the mixed slurry is based on keeping the pH value of the mixed slurry in the circulating oxidation tank controlled at 6 to 6.5.

[0004] The above patent document discloses a flue gas desulfurization process based on the limestone-gypsum desulfurization method. This process allows the lime milk slurry to directly enter the mixed slurry circulation oxidation tank so that the pH value in the slurry can be quickly stabilized when the sulfur dioxide concentration is high. However, this process does not pay attention to the contact efficiency between the limestone slurry and the flue gas. Even if the pH in the slurry is effectively stabilized, if the flue gas cannot fully contact the limestone slurry, a high proportion of sulfur dioxide will remain in the flue gas and be discharged into the atmosphere, thereby causing a great impact on the environment. Therefore, this flue gas desulfurization process still has room for improvement. Summary of the Invention

[0005] In view of the technical defects existing in the background technology, the present invention proposes a limestone-gypsum wet flue gas desulfurization process, which solves the above technical problems and meets practical needs. The specific technical solution is as follows: A limestone-gypsum wet flue gas desulfurization process, comprising a desulfurization tower, a rotary atomization structure, and a flue gas pipeline. The desulfurization tower is hollow and consists of a flue gas discharge zone, a demisting zone, a spraying zone, a rotary atomization zone, and a slurry oxidation zone from top to bottom. The rotary atomization structure is cylindrical and extends from top to bottom. It is located in the rotary atomization area. A liquid infusion tube passes through the axis of the rotary atomization structure. The rotary atomization structure is provided with a plurality of atomization holes extending from the axis of the rotary atomization structure to the side surface. A driving structure for rotating the rotary atomization structure is provided at one end of the rotary atomization structure. The flue gas pipeline runs through the desulfurization tower from the outside and extends between the rotary atomization zone and the slurry oxidation zone; The desulfurization tower is used to desulfurize the flue gas, and the flue gas desulfurization process includes the following steps: S1. The dust-removed flue gas is transported to the area between the rotary atomization zone and the slurry oxidation zone in the desulfurization tower through the flue gas pipeline. The flue gas flows upward along the outer side of the rotary atomization structure and the inner wall of the desulfurization tower. S2, the limestone absorption liquid is sprayed downward from the spray zone to form first droplets and contact the flue gas. At the same time, the limestone absorption liquid is transported to the interior of the rotary atomization structure through the liquid delivery pipe. The rotary atomization structure rotates, causing the limestone absorption liquid to flow through the atomization holes and be atomized into second droplets. The second droplets are sprayed from the surface of the rotary atomization structure and contact the flue gas. S3. The sulfur dioxide in the flue gas is absorbed by the limestone absorption liquid to form desulfurized flue gas. The desulfurized flue gas is removed from the demisting area and then discharged from the desulfurization tower through the flue gas discharge area; S4. After the limestone absorption liquid absorbs sulfur dioxide, it forms an absorption slurry and drips into the slurry oxidation zone for oxidation. After the oxidation is completed, the absorption slurry is discharged from the desulfurization tower and dehydrated to obtain gypsum.

[0006] As a further technical solution of the present invention, one or more layers of spray pipes distributed up and down are provided in the spray area, and a plurality of atomizing nozzles are provided at the bottom of the spray pipes. The atomizing nozzles are evenly distributed above the space between the outer side of the rotary atomizing structure and the inner wall of the desulfurization tower.

[0007] As a further technical solution of the present invention, the axis of the rotary atomization structure passes through an absorption liquid tank extending in the vertical direction, the top of the absorption liquid tank is connected to the infusion tube and the bottom is closed, and the atomization hole extends from the absorption liquid tank to the outer surface of the rotary atomization structure; The aperture of the atomization hole is 50-500 μm.

[0008] As a further technical solution of the present invention, the shape of the atomization hole is elliptical and the ratio of the short axis to the long axis of the ellipse is 1:(3~5).

[0009] As a further technical solution of the present invention, the rotary atomization zone is provided with at least one detection groove, which is arranged horizontally around the inner wall of the desulfurization tower; A pH sensor is provided in the detection tank.

[0010] As a further technical solution of the present invention, the detection tank is distributed in sequence from top to bottom. The pH value setting range of the pH sensor in the top detection tank is 6-6.5, the pH value setting range of the pH sensor in the middle detection tank is 5.5-6, and the pH value setting range of the pH sensor in the bottom detection tank is 4.8-5.5. When the actual pH value detected by the pH sensor is lower than the set range, the spraying amount of the limestone absorption liquid in the spraying area and the rotary atomization area is increased; When the actual pH value detected by the pH sensor is higher than the set range, the spraying amount of the limestone absorption liquid in the spraying area and the rotary atomization area is reduced.

[0011] As a further technical solution of the present invention, a vertically extending partition plate is provided in the slurry oxidation zone, the partition plate divides the slurry oxidation zone into a liquid collecting chamber and an oxidation chamber, and an opening is provided at the bottom of the partition plate to connect the liquid collecting chamber and the oxidation chamber; The top of the liquid collecting chamber is connected to the rotary atomization zone, the oxidation chamber and the rotary atomization zone are not connected to each other, an overflow port is provided on the top edge of the oxidation chamber, and a collection container connected to the overflow port is provided on one side of the oxidation chamber.

[0012] As a further technical solution of the present invention, a bubble ejector is provided at the bottom of the oxidation chamber, the bubble ejector is provided with a blast pipeline extending to the outside of the desulfurization tower, and a blower is provided at the end of the blast pipeline.

[0013] As a further technical solution of the present invention, a smoke exhaust pipe connected to the flue gas emission area is provided on the top of the desulfurization tower, a condenser is provided between the demisting area and the smoke exhaust pipe, and the condenser is provided with a condensation water pipe extending outside the desulfurization tower.

[0014] The beneficial effects of the present invention are: The present invention discloses a limestone-gypsum wet flue gas desulfurization process capable of improving the flue gas desulfurization rate. Sulfur-containing flue gas is transported to a desulfurization tower through a flue gas pipeline and flows from bottom to top. At the same time, limestone absorption liquid is respectively transported to a spraying area and a rotary atomization area to generate first droplets and second droplets respectively. The first droplets are sprayed from top to bottom through an atomizing nozzle and contact with the flue gas to absorb sulfur dioxide in the flue gas. At the same time, the rotary atomizing structure generates centrifugal force through rotation, and the limestone absorption liquid is atomized into second droplets under the shearing action of the atomizing hole and sprayed in a horizontal direction. The first droplets and the second droplets form a limestone droplet network inside the desulfurization tower. The first droplets and the second droplets can complement each other to avoid dead corners inside the desulfurization tower that cannot be covered by the limestone droplets. In addition, the rotary atomizing structure can drive the flue gas to rotate synchronously, so that the flue gas can fully contact with the limestone droplets, which is beneficial to improving the desulfurization rate of the flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a desulfurization tower in a limestone-gypsum wet flue gas desulfurization process.

[0016] Among them: 1-desulfurization tower, 11-flue gas emission area, 111-flue gas exhaust pipe, 12-demist area, 13-spraying area, 131-spraying pipe, 14-rotating atomization area, 141-liquid delivery pipe, 142-detection tank, 15-slurry oxidation area, 151-partition plate, 152-liquid collecting chamber, 153-oxidation chamber, 154-overflow port, 155-bubble ejector, 2-rotating atomization structure, 21-absorption liquid tank, 3-flue gas pipeline, 4-driving structure, 5-collecting container, 6-blowing pipeline, 7-blower, 8-condenser, 81-condensed water pipe. DETAILED DESCRIPTION

[0017] The following describes the implementation methods of the present invention in conjunction with relevant drawings and examples. The implementation methods of the present invention are not limited to the following examples, and the present invention relates to relevant necessary components in this technical field, which should be regarded as common knowledge in this technical field and can be known and mastered by technical personnel in this technical field.

[0018] A limestone-gypsum wet flue gas desulfurization process includes a desulfurization tower 1, a rotary atomization structure 2, and a flue gas pipeline 3. The desulfurization tower 1 is hollow and consists of a flue gas discharge area 11, a demisting area 12, a spraying area 13, a rotary atomization area 14, and a slurry oxidation area 15 from top to bottom. The rotary atomization structure 2 is cylindrical and extends from top to bottom. It is located in the rotary atomization area 14. A liquid infusion tube 141 passes through the axis of the rotary atomization structure 2. The rotary atomization structure 2 is provided with a plurality of atomization holes extending from the axis of the rotary atomization structure 2 to the side surface. A driving structure 4 is provided at one end of the rotary atomization structure 2 to rotate the rotary atomization structure 2. The flue gas pipeline 3 passes through the desulfurization tower 1 from the outside and extends between the rotary atomization zone 14 and the slurry oxidation zone 15; The desulfurization tower 1 is used to desulfurize the flue gas. The flue gas desulfurization process includes the following steps: S1, the dust-removed flue gas is transported to the space between the rotary atomization zone 14 and the slurry oxidation zone 15 in the desulfurization tower 1 through the flue gas pipeline 3, and the flue gas flows upward along the outer side of the rotary atomization structure 2 and the inner wall of the desulfurization tower 1; S2: The limestone absorption liquid is sprayed downward from the spraying area 13 to form first droplets that come into contact with the flue gas. At the same time, the limestone absorption liquid is transported to the interior of the rotary atomizing structure 2 by the liquid delivery pipe 141. The rotary atomizing structure 2 rotates, causing the limestone absorption liquid to flow through the atomizing holes and be atomized into second droplets. The second droplets are sprayed from the surface of the rotary atomizing structure 2 and come into contact with the flue gas. S3, the sulfur dioxide in the flue gas is absorbed by the limestone absorption liquid to form desulfurized flue gas, which is then removed from the demisting area 12 to remove moisture and then discharged from the desulfurization tower 1 through the flue gas discharge area 11; S4. After the limestone absorption liquid absorbs sulfur dioxide, it forms an absorption slurry and drips into the slurry oxidation zone 15 for oxidation. After the oxidation is completed, the absorption slurry is discharged from the desulfurization tower 1 and dehydrated to obtain gypsum.

[0019] The present invention discloses a process for removing sulfur dioxide from flue gas based on a limestone-gypsum wet desulfurization method. The process requires a desulfurization tower 1 and a rotary atomization structure 2 and a flue gas pipeline 3 therein to perform a desulfurization operation on the flue gas. Figure 1 , the flue gas containing sulfur dioxide generated in industrial production is transported to the inside of the desulfurization tower 1 through the flue gas pipeline 3. The flue gas pipeline 3 can pass through the bottom of the desulfurization tower 1 to the slurry oxidation zone 15 and then extend to between the slurry oxidation zone 15 and the rotary atomization zone 14. The flue gas can exchange heat with the limestone absorption liquid that has absorbed sulfur dioxide in the slurry oxidation zone 15 in the flue gas pipeline 3, and then the flue gas is released from the bottom of the rotary atomization zone 14 and flows upward. In the process of flowing upward, the flue gas successively contacts the second droplets in the rotary atomization zone 14 and the first droplets in the spraying zone 13. The first droplets and the second droplets are both atomized from the limestone absorption liquid. In the process of contact between the flue gas and the limestone absorption liquid, sulfur dioxide will be absorbed into the limestone absorption liquid, thereby obtaining desulfurized flue gas with sulfur dioxide removed. The desulfurized flue gas is demisted in the demisting zone 12 and then discharged from the desulfurization tower 1 through the flue gas discharge zone 11; Furthermore, the outside of the desulfurization tower 1 is provided with a container for the prepared limestone absorption liquid. The limestone absorption liquid is extracted by a fluid pump and then transported through the infusion pipe 141. The infusion pipe 141 transports the limestone absorption liquid to the interior of the rotary atomization structure 2. The driving structure 4 is preferably a waterproof motor and is used to drive the rotary atomization structure 2 to rotate. The centrifugal force generated by the rotating rotary atomization structure 2 will cause the limestone absorption liquid inside to move along the atomization hole to the surface of the side of the rotary atomization structure 2. The limestone absorption liquid will be torn into small particle structures during the movement along the atomization hole, so that these limestone absorption liquids are atomized into second droplets and sprayed from the surface of the rotary atomization structure 2. The second droplets will contact the upward-flowing flue gas in the rotary atomization area 14, thereby absorbing sulfur dioxide in the flue gas. It should be noted that the atomization holes will make the surface of the rotary atomization structure 2 uneven, and during its rotation, the surrounding air will be driven to rotate in the direction of rotation of the rotary atomization structure 2. Specifically, the flue gas is stirred by the rotary atomization structure 2 in the rotary atomization zone 14 and flows upward in a spiral along the surface of the rotary atomization structure 2, thereby forming an upward-flowing vortex of the flue gas in the rotary atomization zone 14, which is beneficial to improving the uniformity of the dispersion of the flue gas inside the desulfurization tower 1. In addition, the flue gas extends its flow path by flowing upward in the rotary atomization zone 14, which can make the flue gas more fully contact with the limestone absorption liquid, thereby improving the efficiency of the limestone absorption liquid in absorbing sulfur dioxide in the flue gas in the rotary atomization zone 14, which is beneficial to improving the desulfurization rate of the flue gas. Furthermore, one or more layers of spray pipes 131 distributed up and down are provided in the spray area 13, and a plurality of atomizing nozzles are provided at the bottom of the spray pipe 131, and the plurality of atomizing nozzles are evenly distributed above the space between the outer side of the rotary atomizing structure 2 and the inner wall of the desulfurization tower 1; after the flue gas undergoes a desulfurization treatment in the rotary atomizing area 14, the flue gas will continue to flow upward from the top of the rotary atomizing area 14 and enter the spray area 13, and the spray pipe 131 is also used to transport limestone absorption liquid. The fluid pump draws the limestone absorption liquid in the container containing the limestone absorption liquid into the spray pipe 131 and transports it to the spray area 13. The limestone absorption liquid is atomized into first droplets through the plurality of atomizing nozzles at the bottom of the spray pipe 131, which are sprayed downward and contact the flue gas. At this time, the flue gas contacts the first droplets for a second desulfurization treatment; It should be noted that, in the desulfurization tower 1 of the present invention, the limestone absorption liquid in the spraying zone 13 and the rotary atomization zone 14 can play a synergistic role with each other. The first droplets formed in the spraying zone 13 move from top to bottom and contact the flue gas, while the second droplets formed in the rotary atomization zone 14 move in the horizontal direction and contact the flue gas. The two droplets moving in different directions form a limestone droplet network inside the desulfurization tower 1. The first droplets and the second droplets can complement each other to avoid dead corners inside the desulfurization tower 1 that cannot be covered by the limestone droplets, so that the flue gas can fully contact the limestone droplets, which is beneficial to improving the desulfurization rate of the flue gas. After the flue gas undergoes two desulfurization treatments, the desulfurization rate is significantly improved. It should be further explained that when there are two or more layers of spray pipes 131 in the spray area 13, the distance between adjacent spray pipe layers is 1~2m, and the projections of the spray pipes 131 in the adjacent spray pipe layers in the vertical direction are staggered. This structure is conducive to improving the coverage rate of the first droplets in the spray area 13, so that the first droplets are in full contact with the flue gas; in addition, in order to enable the rotary atomization structure 2 to effectively drive the flue gas to rotate when it rotates, the length of the rotary atomization zone 14 is usually longer than that of the spray area 13. The rotary atomization structure 2 with a longer length and a larger surface area fully rubs with the flue gas and better drives the flue gas to rotate. The ratio of the length of the spray area 13 to the rotary atomization zone 14 is 1:(1.5~3), and the actual lengths of the desulfurization tower 1 and the spray area 13 and the rotary atomization zone 14 need to be adaptively adjusted according to the design flue gas flow treatment standard of the desulfurization tower 1, so that the desulfurization tower 1 can better meet the actual production needs; Furthermore, a smoke exhaust pipe 111 is provided on the top of the desulfurization tower 1, which is connected to the smoke exhaust area 11. A demister is provided in the demisting area 12. A condenser 8 is provided between the demisting area 12 and the smoke exhaust pipe 111. The condenser 8 is provided with a condensing water pipe 81 extending to the outside of the desulfurization tower 1. After the smoke is desulfurized twice in the rotary atomization area 14 and the spraying area 13, most of the sulfur dioxide in the smoke has been absorbed into the limestone absorption liquid, thereby forming desulfurized smoke. After passing through the spraying area 13, the desulfurized smoke continues to flow upward and enters the demisting area 12. The demisting The desulfurization device can remove liquid droplets carried in the desulfurized flue gas to prevent the desulfurized flue gas from containing a large amount of water and affecting the normal operation of the subsequent equipment for treating the desulfurized flue gas. The desulfurized flue gas after demisting continues to flow upward and contacts the condenser 8. The condenser 8 can be connected to the cooling water in the factory. The cooling water reduces the temperature of the desulfurized flue gas to below the dew point when it contacts the condenser 8, thereby forming condensed water. The gaseous water in the desulfurized flue gas is removed and the moisture content in the desulfurized flue gas is further reduced. The desulfurized flue gas after condensation is discharged from the interior of the desulfurization tower 1 through the exhaust pipe 111. Furthermore, after the limestone droplets absorb sulfur dioxide in the flue gas, they drip downward and gather in the slurry oxidation zone 15 to form an absorption slurry. At this time, the main component of the absorption slurry is calcium sulfite. The calcium sulfite needs to be forcibly oxidized into calcium sulfate in the slurry oxidation zone 15 by means of blowing air to generate bubbles, etc., i.e., the target product of the flue gas desulfurization process of the present invention. The slurry containing calcium sulfate is subsequently crystallized and dehydrated to obtain gypsum. Furthermore, a vertically extending partition plate 151 is provided in the slurry oxidation zone 15, which divides the slurry oxidation zone 15 into a liquid collecting chamber 152 and an oxidation chamber 153. An opening is provided at the bottom of the partition plate 151 to connect the liquid collecting chamber 152 with the oxidation chamber 153. The top of the liquid collecting chamber 152 is connected to the rotary atomization zone 14, and the oxidation chamber 153 is not connected to the rotary atomization zone 14. An overflow port 154 is provided at the top edge of the oxidation chamber 153, and a collection container 5 connected to the overflow port 154 is provided on one side of the oxidation chamber 153. A bubble ejector 155 is provided at the bottom of the oxidation chamber 153. The bubble ejector 155 is provided with a blast pipe 6 extending to the outside of the desulfurization tower 1, and a blower 7 is provided at the end of the blast pipe 6. After the slurry oxidation zone 15 adopts the above structure, the absorption slurry will first gather in the liquid collecting chamber 152. The absorption slurry in the liquid collecting chamber 152 is a slurry mainly containing calcium sulfite. These slurries will flow from the liquid collecting chamber 152 to the oxidation chamber 153 along the opening at the bottom of the partition plate 151. At this time, the blower 7 is running to generate airflow and transport it to the inside of the oxidation chamber 153 through the blast pipe 6. The airflow passes through the bubble ejector 155 to generate many dense small bubbles and inject them into the absorption slurry in the oxidation chamber 153. These small bubbles will The absorption slurry is promoted to oxidize calcium sulfite into calcium sulfate, thereby realizing the forced oxidation of the absorption slurry. Since the absorption slurry gradually diffuses upward from the bottom of the oxidation chamber 153, it has enough time to be fully oxidized in the oxidation chamber 153. The absorption slurry that diffuses to the top of the oxidation chamber 153 and completes forced oxidation will overflow from the overflow port 154 into the collection container 5. When a certain amount of absorption slurry is collected in the collection container 5, it is pumped to the next process through a fluid pump for crystallization, dehydration and other operations to obtain the product gypsum.

[0020] As one of the preferred embodiments of the present invention, the axis of the rotary atomization structure 2 passes through an absorption liquid tank 21 extending in the vertical direction. The top of the absorption liquid tank 21 is connected to the infusion tube 141 and the bottom is closed. The atomization hole extends from the absorption liquid tank 21 to the outer surface of the rotary atomization structure 2; the aperture of the atomization hole is 50~500μm; the shape of the atomization hole is elliptical and the ratio of the short axis to the long axis of the ellipse is 1:(3~5); After the atomizing hole adopts the above structure, the elliptical atomizing hole can generate a higher shear force on the limestone absorption liquid when the rotating atomizing structure 2 rotates to throw out the limestone absorption liquid, which is conducive to forming more uniform and smaller second droplets. When the size of the second droplets is reduced, the total specific surface area of ​​all second droplets will increase, which is conducive to more sufficient contact between the second droplets and the flue gas, thereby improving the desulfurization rate of the flue gas.

[0021] As one of the preferred embodiments of the present invention, the rotary atomization zone 14 is provided with at least one detection tank 142, which is arranged horizontally along the inner wall of the desulfurization tower 1. A pH sensor is provided in the detection tank 142. The detection tank 142 is used to receive the limestone absorption liquid that has partially absorbed sulfur dioxide and measure the pH value of the limestone absorption liquid through the pH sensor. The pH value of the limestone absorption liquid is used to determine whether the spraying amount of the limestone absorption liquid is sufficient, thereby dynamically adjusting the spraying amount of the limestone absorption liquid. Furthermore, there are three detection slots 142 distributed from top to bottom. The setting range of the pH value detected by the pH sensor in the top detection slot 142 is 6~6.5, the setting range of the pH value detected by the pH sensor in the middle detection slot 142 is 5.5~6, and the setting range of the pH value detected by the pH sensor in the bottom detection slot 142 is 4.8~5.5; when the actual pH value detected by the pH sensor is lower than the setting range, the spraying amount of the limestone absorption liquid in the spraying area 13 and the rotary atomization area 14 is increased; when the actual pH value detected by the pH sensor is higher than the setting range, the spraying amount of the limestone absorption liquid in the spraying area 13 and the rotary atomization area 14 is reduced.

[0022] In summary, the present invention discloses a limestone-gypsum wet flue gas desulfurization process that can improve the flue gas desulfurization rate. The sulfur-containing flue gas is transported to the desulfurization tower 1 through the flue gas pipeline 3 and flows from bottom to top. At the same time, the limestone absorption liquid is transported to the spray area 13 and the rotary atomization area 14 respectively and generates first droplets and second droplets respectively. The first droplets are sprayed from top to bottom through the atomizing nozzle and contact with the flue gas to absorb sulfur dioxide in the flue gas. At the same time, the rotary atomizing structure 2 generates centrifugal force through rotation and the shearing action of the atomizing hole to atomize the limestone absorption liquid into second droplets and spray them in a horizontal direction. The first droplets and the second droplets form a limestone droplet network inside the desulfurization tower 1. The first droplets and the second droplets can complement each other to avoid dead corners inside the desulfurization tower 1 that cannot be covered by the limestone droplets, and the rotary atomizing structure 2 will drive the flue gas to rotate synchronously, so that the flue gas can fully contact with the limestone droplets, which is beneficial to improving the desulfurization rate of the flue gas.

[0023] The above description is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A limestone-gypsum wet flue gas desulfurization process, characterized in that: It includes a desulfurization tower, a rotary atomization structure, and a flue gas pipeline. The desulfurization tower is hollow and consists of a flue gas discharge area, a demisting area, a spraying area, a rotary atomization area, and a slurry oxidation area from top to bottom. The rotary atomization structure is cylindrical and extends from top to bottom. It is located in the rotary atomization area. A liquid infusion tube passes through the axis of the rotary atomization structure. The rotary atomization structure is provided with a plurality of atomization holes extending from the axis of the rotary atomization structure to the side surface. A driving structure for rotating the rotary atomization structure is provided at one end of the rotary atomization structure. The flue gas pipeline runs through the desulfurization tower from the outside and extends between the rotary atomization zone and the slurry oxidation zone; The desulfurization tower is used to desulfurize the flue gas, and the flue gas desulfurization process includes the following steps: S1. The dust-removed flue gas is transported to the area between the rotary atomization zone and the slurry oxidation zone in the desulfurization tower through the flue gas pipeline. The flue gas flows upward along the outer side of the rotary atomization structure and the inner wall of the desulfurization tower. S2, the limestone absorption liquid is sprayed downward from the spray zone to form first droplets and contact the flue gas. At the same time, the limestone absorption liquid is transported to the interior of the rotary atomization structure through the liquid delivery pipe. The rotary atomization structure rotates, causing the limestone absorption liquid to flow through the atomization holes and be atomized into second droplets. The second droplets are sprayed from the surface of the rotary atomization structure and contact the flue gas. S3. The sulfur dioxide in the flue gas is absorbed by the limestone absorption liquid to form desulfurized flue gas. The desulfurized flue gas is removed from the demisting area and then discharged from the desulfurization tower through the flue gas discharge area; S4. After the limestone absorption liquid absorbs sulfur dioxide, it forms an absorption slurry and drips into the slurry oxidation zone for oxidation. After the oxidation is completed, the absorption slurry is discharged from the desulfurization tower and dehydrated to obtain gypsum.

2. The limestone-gypsum wet flue gas desulfurization process according to claim 1, characterized in that: The spray area is provided with one or more layers of spray pipes distributed up and down, and a plurality of atomizing nozzles are provided at the bottom of the spray pipes. The atomizing nozzles are evenly distributed above the space between the outer side of the rotary atomizing structure and the inner wall of the desulfurization tower.

3. The limestone-gypsum wet flue gas desulfurization process according to claim 1, characterized in that: The axis of the rotary atomization structure passes through an absorption liquid tank extending in the vertical direction. The top of the absorption liquid tank is connected to the infusion tube and the bottom is closed. The atomization hole extends from the absorption liquid tank to the outer surface of the rotary atomization structure. The aperture of the atomization hole is 50-500 μm.

4. The limestone-gypsum wet flue gas desulfurization process according to claim 1, characterized in that: The shape of the atomization hole is elliptical, and the ratio of the short axis to the long axis of the ellipse is 1:(3-5).

5. The limestone-gypsum wet flue gas desulfurization process according to claim 1, characterized in that: The rotary atomization area is provided with at least one detection groove, which is arranged horizontally around the inner wall of the desulfurization tower; A pH sensor is provided in the detection tank.

6. The limestone-gypsum wet flue gas desulfurization process according to claim 5, characterized in that: There are three detection slots distributed from top to bottom. The pH value setting range of the pH sensor in the top detection slot is 6-6.5, the pH value setting range of the pH sensor in the middle detection slot is 5.5-6, and the pH value setting range of the pH sensor in the bottom detection slot is 4.8-5.

5. When the actual pH value detected by the pH sensor is lower than the set range, the spraying amount of the limestone absorption liquid in the spraying area and the rotary atomization area is increased; When the actual pH value detected by the pH sensor is higher than the set range, the spraying amount of the limestone absorption liquid in the spraying area and the rotary atomization area is reduced.

7. The limestone-gypsum wet flue gas desulfurization process according to claim 1, characterized in that: A vertically extending partition plate is provided in the slurry oxidation zone, the partition plate divides the slurry oxidation zone into a liquid collecting chamber and an oxidation chamber, and an opening is provided at the bottom of the partition plate to connect the liquid collecting chamber and the oxidation chamber; The top of the liquid collecting chamber is connected to the rotary atomization zone, the oxidation chamber and the rotary atomization zone are not connected to each other, an overflow port is provided on the top edge of the oxidation chamber, and a collection container connected to the overflow port is provided on one side of the oxidation chamber.

8. The limestone-gypsum wet flue gas desulfurization process according to claim 7, characterized in that: A bubble ejector is provided at the bottom of the oxidation chamber. The bubble ejector is provided with an air blast pipeline extending to the outside of the desulfurization tower. A blower is provided at the end of the air blast pipeline.

9. The limestone-gypsum wet flue gas desulfurization process according to claim 1, characterized in that: A smoke exhaust pipe communicating with the smoke exhaust area is provided on the top of the desulfurization tower. A condenser is provided between the demisting area and the smoke exhaust pipe. The condenser is provided with a condensing water pipe extending to the outside of the desulfurization tower.

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