A spraying layer for a wet flue gas desulfurization system

Abstract

The utility model provides a kind of spraying layer for wet flue gas desulfurization, including multiple layers by spraying main pipe, spraying branch pipe, nozzle, support beam being constituted and being located in absorption tower, its characterized in that multiple roots are set to spraying main pipe, and the pipe diameter of each spraying main pipe is sequentially reduced from import end to export end, multiple roots of spraying branch pipe are connected at the both sides of spraying main pipe with interval, and the pipe diameter of each spraying branch pipe is sequentially reduced from import end to export end, and nozzle is connected at the both sides of spraying branch pipe with interval.Effectively increase gas-liquid contact area, make gas-liquid mixing more completely, more fully, greatly improve pollutant removal efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of waste gas treatment technology, specifically relating to a spray layer for wet flue gas desulfurization, which is also applicable to spray dust removal in related industries. Background Technology

[0002] Coal-fired flue gas contains large amounts of SO2 and dust, as well as small amounts of pollutants such as HCl, HF, SO3, and heavy metals, seriously endangering human health and the living environment. To address this, relevant government departments in various countries have formulated a series of laws and regulations, while some regions have introduced even stricter air pollutant control measures, requiring newly built and under-construction thermal power generating units to adopt clean flue gas emission technologies to achieve ultra-clean emissions. Currently, the most commonly used flue gas desulfurization process is wet flue gas desulfurization. This involves the flue gas entering the absorption tower, passing through a spray layer and a demister in a bottom-up flow, before being discharged through a chimney. During this upward flow, the limestone-gypsum solution sprayed from top to bottom contacts the flue gas, causing physical and chemical reactions that wash away SO2. Simultaneously, dust particles in the flue gas undergo inertial collisions, interception, diffusion, agglomeration, and gravitational settling, separating the dust from the flue gas. Therefore, the spray layer is the core component of the absorption tower, directly affecting the pollutant removal efficiency.

[0003] Because flue gas forms a vortex zone after entering the absorption tower, the velocity distribution of the flue gas within the tower is uneven, leading to inconsistent desulfurization and dust removal effects, directly impacting desulfurization and dust removal efficiency. Therefore, to improve the uniformity of flue gas distribution, some absorption towers employ gas-liquid distribution devices such as trays and Venturi rods. While these improve the uniformity of flue gas distribution to some extent, the large cross-sectional area of ​​the tower, coupled with the fact that the gas-liquid distributor cannot be set too large due to resistance limitations, results in very limited improvement in flue gas uniformity. Furthermore, while conventional spray layer nozzles are arranged to achieve uniformity, they do not match the actual flue gas distribution, leading to insufficient gas-liquid contact and failing to fully realize the desulfurization effect. Furthermore, due to objective limitations, the coverage of the sprayed slurry near the inner wall of the tower is much lower than that at the center. When the slurry is sprayed onto the inner wall, it forms a liquid film and flows downwards along the inner wall, resulting in poor gas-liquid contact. Consequently, some flue gas leaves the absorption tower without sufficient gas-liquid contact, causing the flue gas to "escape" along the inner wall of the absorption tower, creating a sidewall effect that affects the overall desulfurization and dust removal efficiency. Therefore, it is necessary to improve the existing technology. Utility Model Content

[0004] To address the problems existing in the prior art, this utility model provides a spray layer for wet flue gas desulfurization, aiming to reduce the sidewall effect of the absorption tower and improve desulfurization and dust removal efficiency.

[0005] This utility model is achieved through the following technical solution: a spray layer for wet flue gas desulfurization, comprising multiple spray layers consisting of a main spray pipe, spray branch pipes, nozzles, and support beams, located within an absorption tower. The main spray pipes are characterized by having multiple main spray pipes, each with a diameter decreasing sequentially from the inlet to the outlet. Multiple spray branch pipes are connected at intervals on both sides of the main spray pipe, each with a diameter decreasing sequentially from the inlet to the outlet. Nozzles are connected at intervals on both sides of the spray branch pipes, ensuring that the liquid flow rate at the outlet of the main spray pipe matches the liquid flow rate at the inlet of the main spray pipe. Simultaneously, the inlet pressure deviation of each nozzle in each spray layer is ensured to be within 5%, effectively improving desulfurization and dust removal efficiency.

[0006] Furthermore, each spray layer is staggered by 10-18° in the circumferential direction to enhance the spraying effect and improve desulfurization and dust removal efficiency.

[0007] Furthermore, the nozzle layout of each spray layer is adapted to the flue gas velocity, with a high nozzle density in high velocity regions and a low nozzle density in low velocity regions. The specific settings are determined based on flue gas CFD simulation experiments.

[0008] Furthermore, the nozzle flow rate of each spray layer is non-uniform. The nozzle flow rate near the tower wall is 1.1 to 1.5 times that of the nozzle flow rate at the center of the tower. The specific flow rate is determined based on flue gas CFD simulation experiments and nozzle layout density.

[0009] Furthermore, the nozzle structure of each spray layer is different. The nozzles near the tower wall are solid cone structures, while the nozzles at the center of the tower are hollow cone structures, in order to reduce the influence of the absorption tower sidewall effect and further improve the desulfurization and dust removal effect.

[0010] Furthermore, in the multi-layer spray layer, all the nozzles in the uppermost spray layer are unidirectional downward spray nozzles, while the nozzles in the remaining spray layers are bidirectional nozzles that spray alternately upward and downward.

[0011] Furthermore, the inlet and outlet ends of the multiple spray pipes of each spray layer extend out of the tower through the sealing through holes on the tower wall, and the middle parts of the multiple spray pipes extend to both sides of the horizontal support beam through the corresponding through holes on at least one horizontal support beam, so as to fix them to the horizontal support beam by perforation, and then fix the two ends of the horizontal support beam inside the absorption tower.

[0012] Furthermore, the concentration and flow rate of the desulfurizing agent sprayed by the nozzles of each spray layer are adapted to the flue gas distribution in order to improve the gas-liquid contact reaction efficiency, reduce the sidewall effect of the absorption tower, and improve the desulfurization and dust removal effect.

[0013] Furthermore, the number of nozzles on the spray branch pipe located at the outlet end of the main spray pipe is greater than the number of nozzles on the spray branch pipe located at the inlet end of the main spray pipe.

[0014] Compared with the prior art, the present invention provides the following advantages and technical effects: (1) By using the nozzle layout in different areas of the spray layer and the distribution of the flow rate of the nozzles near the tower wall to be 1.1 to 1.5 times that of the flow rate of the nozzles in the center of the tower, the sidewall effect caused by the low density of the nozzles at the tower wall is compensated, so that the gas-liquid mixing is more complete and sufficient, and the pollutant removal efficiency is higher.

[0015] (2) The nozzles near the tower wall of the same spray layer adopt a solid cone structure, while the nozzles in the center of the tower adopt a hollow cone structure. The solid cone nozzles effectively reduce the amount of slurry sprayed onto the tower wall, greatly alleviate the side wall effect, reduce the slurry scouring of the tower wall, and extend the service life of the tower wall anti-corrosion layer. The slurry droplets sprayed by the hollow cone nozzles in the center of the tower are smaller and finer, making the gas-liquid contact area larger and effectively improving the pollutant removal efficiency.

[0016] (3) The nozzle layout and orientation of different spray layers are different. That is, the top spray layer uses a unidirectional downward spray nozzle, which reduces the demisting load of the upper demister and increases the spray intensity below. The other spray layers use bidirectional nozzles that spray upward and downward, which increases the chance of gas-liquid contact and allows the flue gas flowing into the top to be subjected to the high-intensity downward spray slurry and upward spray slurry, further removing residual SO2 and dust, so that pollutants are completely removed.

[0017] (4) The main spray pipe adopts a multi-pipe layout to solve the problem that the large diameter of a single main spray pipe causes uneven slurry distribution in the spray branch pipes and nozzles, which affects the spraying effect.

[0018] (5) After the adjacent spray layers are staggered by 10-18° in the circumferential direction, the spray layers are staggered to each other, which further improves the slurry coverage of the entire spray area.

[0019] (6) By setting different inlet and outlet pipe diameters of the main spray pipe and the branch spray pipe, the inlet pressure deviation of each nozzle is controlled within 5%, ensuring that each nozzle can work normally, so that the angle and particle size of the sprayed slurry are in the best state, and further improving the removal efficiency.

[0020] (7) Each spray layer is fixed and supported by a support beam, which effectively improves the stability of each nozzle. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a spray layer structure according to this utility model; Figure 2 This is a partial schematic diagram of the connection between the main sprinkler pipe and the support beam.

[0022] In the diagram: 1-Sprinkler main pipe, 2-Support beam, 3-Solid cone nozzle, 4-Hollow cone nozzle, 5-Sprinkler branch pipe. Detailed Implementation

[0023] The present invention will now be further described with reference to the accompanying drawings.

[0024] The wet flue gas desulfurization spray layer provided by this utility model includes multiple spray layers located inside the absorption tower, consisting of a main spray pipe 1, spray branch pipes 5, nozzles 3 and 4, and a support beam 2. Multiple main spray pipes 1 are provided, with the diameter of each main spray pipe 1 decreasing sequentially from the inlet end to the outlet end. Multiple spray branch pipes 5 are connected at intervals on both sides of the main spray pipe 1, with the diameter of each spray branch pipe 5 decreasing sequentially from the inlet end to the outlet end. Nozzles 3 are connected at intervals on both sides of the spray branch pipes 5. The number of nozzles 3 on the spray branch pipes 5 located at the outlet end of the main spray pipe 1, especially between the support beam 2 and the outlet end of the main spray pipe 1, is greater than the number of nozzles 3 on the spray branch pipes 5 at the inlet end of the main spray pipe 1. This ensures that the liquid flow rate at the outlet end of the main spray pipe 1 matches the liquid flow rate at the inlet end of the main spray pipe 1, while ensuring that the inlet pressure deviation of each nozzle 3 in each spray layer is within 5%, effectively improving desulfurization and dust removal efficiency. Each spray layer is staggered by 10-18° in the circumferential direction to enhance the spraying effect and improve desulfurization and dust removal efficiency. The nozzle layout of each spray layer is adapted to the flue gas velocity. The nozzle layout density is large in the high velocity region and small in the low velocity region. The specific settings are determined based on the flue gas CFD simulation test. The flow rate of nozzle 3 in each spray layer is non-uniform. The flow rate of nozzle 4 near the tower wall is 1.1 to 1.5 times that of nozzle 3 at the center of the tower. The specific flow rate is determined based on flue gas CFD simulation test and nozzle layout density. The nozzle structure of each spray layer is different. The nozzle 4 near the tower wall is a solid cone structure, and the nozzle 3 in the center of the tower is a hollow cone structure, so as to reduce the influence of the side wall effect of the absorption tower and further improve the desulfurization and dust removal effect. In the multi-layer spray layer, the nozzles 3 and 4 in the uppermost spray layer are all unidirectional downward spray nozzles, while the nozzles 3 and 4 in the other spray layers are bidirectional nozzles that spray upward and downward alternately. The inlet and outlet ends of the four spray pipes 1 of each spray layer extend out of the tower through the sealing through holes on the tower wall. The middle part of the four spray pipes 1 extends to both sides of the horizontal support beam 2 through the corresponding through holes on the horizontal support beam 2, so that the spray pipes 1 can be fixed on the horizontal support beam 2 by the perforation method, and then the two ends of the horizontal support beam 2 can be fixed inside the absorption tower. The concentration and flow rate of the desulfurizing agent sprayed by nozzles 3 and 4 in each spray layer are adapted to the flue gas distribution in order to improve the gas-liquid contact reaction efficiency, reduce the sidewall effect of the absorption tower, and improve the desulfurization and dust removal effect.

[0025] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A spray layer for wet flue gas desulfurization, comprising multiple spray layers consisting of a main spray pipe, branch spray pipes, nozzles, and support beams disposed within an absorption tower, characterized in that... Multiple main spray pipes are installed, with the diameter of each main spray pipe decreasing from the inlet end to the outlet end. Multiple branch spray pipes are connected at intervals on both sides of the main spray pipe, with the diameter of each branch spray pipe decreasing from the inlet end to the outlet end. Nozzles are connected at intervals on both sides of the branch spray pipe.

2. The spray layer for wet flue gas desulfurization according to claim 1, characterized in that... Each spray layer is staggered by 10-18° in the circumferential direction.

3. Each of the spray layers for wet flue gas desulfurization according to claim 1, characterized in that... The nozzle layout of each spray layer is adapted to the flue gas velocity. The nozzle layout density is large in the high velocity region and small in the low velocity region. The specific settings are determined based on flue gas CFD simulation tests.

4. The spray layer for wet flue gas desulfurization according to claim 1, characterized in that... The nozzle flow rate of each spray layer is non-uniform. The flow rate of the nozzles near the tower wall is 1.1 to 1.5 times that of the nozzles at the center of the tower. The specific flow rate is determined based on flue gas CFD simulation tests and nozzle layout density.

5. The spray layer for wet flue gas desulfurization according to claim 1, characterized in that... The nozzle structure of each spray layer is different; the nozzles near the tower wall are solid cones, while the nozzles at the center of the tower are hollow cones.

6. The spray layer for wet flue gas desulfurization according to claim 1, characterized in that... In the multi-layer spray system, all nozzles in the topmost spray layer are unidirectional downward spray nozzles, while the nozzles in the remaining spray layers are bidirectional nozzles that spray alternately upward and downward.

7. The spray layer for wet flue gas desulfurization according to claim 1, characterized in that... The inlet and outlet ends of the multiple spray pipes of the spray layer extend out of the tower through the sealing through holes on the tower wall, and the middle parts of the multiple spray pipes extend to both sides of the horizontal support beam through the corresponding through holes on at least one horizontal support beam.

8. The spray layer for wet flue gas desulfurization according to claim 1, characterized in that... The concentration and flow rate of the desulfurizing agent sprayed by the nozzles of each spray layer are adapted to the flue gas distribution.

9. The spray layer for wet flue gas desulfurization according to claim 1, characterized in that... The number of nozzles on the spray branch pipe at the outlet end of the main spray pipe is greater than the number of nozzles on the spray branch pipe at the inlet end of the main spray pipe.

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