A fixed bed purification tower for removing phosphorus from yellow phosphorus tail gas

Abstract

The utility model discloses a kind of fixed bed purification towers for dephosphorization of yellow phosphorus tail gas, including tower base, tower top, air inlet pipe and air outlet pipe, the tower body is provided between the tower base and tower top, the adjacent side of the tower base and tower top and tower body is provided with flange ring, the tower base and tower top are fixedly connected with the tower body by bolt across flange ring, the inside of the tower top is provided with regeneration pipeline;The tower body includes multiple straight pipe sections.The fixed bed purification tower for dephosphorization of yellow phosphorus tail gas, the particle size of adsorbent medium layer in multiple straight pipe sections gradually decreases along gas flow direction, yellow phosphorus tail gas enters tower base after from air inlet pipe, from bottom to top gradually through adsorbent medium layer, adsorbent medium layer uses the gradient design that aperture gradually reduces from bottom to top, can ensure that yellow phosphorus tail gas and adsorbent medium layer are fully contacted, improve the contact efficiency between the two, by CFD simulation optimization guide structure parameter, make yellow phosphorus tail gas residence time more concentrated, promote mass transfer rate and adsorption efficiency.

Description

Technical Field

[0001] This utility model relates to the field of gas adsorption treatment technology, specifically a fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas. Background Technology

[0002] Yellow phosphorus is an important chemical product, and its production mainly adopts the electric furnace method. Yellow phosphorus tail gas is the tail gas generated during the production of yellow phosphorus. It is mainly formed by the high-temperature reaction and incomplete combustion of raw materials. It contains harmful substances such as carbon monoxide, phosphine, and hydrogen sulfide, which pollute the atmospheric environment. Fixed bed adsorption towers are needed to adsorb and purify the harmful substances in the process. The existing patent authorization announcement number CN218421898U discloses a fixed bed activated carbon adsorber. It sets multiple layers of wire mesh at the bottom grid of the activated carbon layer. The pore size of the top layer of wire mesh is smaller than the particle size of the activated carbon. A layer of alumina balls, gravel or other ceramic materials is laid on top of the wire mesh. The activated carbon is laid on the upper part of the alumina balls, gravel or other ceramic materials layer to achieve the purpose of avoiding carbon leakage. A layer of wire mesh is set on top of the activated carbon layer. The pore size of the wire mesh is smaller than the particle size of the activated carbon. A layer of alumina balls, gravel or other ceramic materials is laid on the upper part of the wire mesh to achieve the purpose of preventing activated carbon particles from being carried out by the airflow. When the above-mentioned patent is used for the purification of yellow phosphorus tail gas, the fixed bed is uniformly filled. Since the adsorbent particle size distribution is uniform, using small-particle adsorbent to improve the mass transfer effect will significantly increase the pressure drop of the bed and increase energy consumption. If large-particle adsorbent is selected to reduce the pressure drop, the mass transfer rate will decrease due to the longer diffusion path, which will affect the adsorption efficiency. In addition, the replacement of adsorbent relies on manual operation through the manhole on the tower, which poses a high safety risk and the replacement is not thorough. Summary of the Invention

[0003] The purpose of this invention is to provide a fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas, so as to solve the problems mentioned in the background art, such as the fixed bed being uniformly filled, affecting the adsorption efficiency, and the high safety risk and incomplete replacement of the adsorbent due to manual operation through the manhole on the tower body.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas, comprising a tower base, a tower top, an inlet pipe, and an outlet pipe. A tower body is provided between the tower base and the tower top. Flange rings are provided on the adjacent sides of the tower base, tower top, and tower body. The tower base and tower top are fixedly connected to the tower body by bolts passing through the flange rings. A regeneration pipeline is provided inside the tower top. The tower body includes multiple straight pipe sections. The top and bottom of the multiple straight pipe sections are fixedly connected with connecting flanges. The multiple straight pipe sections are vertically stacked and connected. A support grid is fixedly connected to the bottom of each of the multiple straight pipe sections. A wire mesh layer is laid on top of the support grid. An adsorbent medium layer is laid above the wire mesh layer. The particle size of the adsorbent medium layer in the multiple straight pipe sections gradually decreases along the gas flow direction.

[0005] Preferably, the height of the plurality of straight pipe sections is set according to the corresponding adsorbent medium layer.

[0006] Preferably, the multiple straight pipe sections are fixedly connected by connecting flanges on adjacent sides and bolts.

[0007] Preferably, a groove is provided on the mating surface of the mating flange, and a high-temperature sealing gasket is fitted inside the groove.

[0008] Preferably, a grid pressure plate is fixedly installed at the bottom of the tower top, and the grid pressure plate is disposed abutting against the top of the tower body.

[0009] Preferably, sampling tubes penetrating the straight pipe sections are fixedly installed on the outer walls of each of the multiple straight pipe sections.

[0010] Preferably, the regeneration pipeline includes an annular pipe fixedly installed on the inner wall of the tower top, with nozzles arranged equidistantly at the bottom of the annular pipe facing the tower body, and a delivery pipe located outside the tower top fixedly connected to the outer wall of the annular pipe.

[0011] Preferably, the air inlet pipe and the air outlet pipe are fixedly connected to the outer walls of the tower base and the tower top, respectively.

[0012] Compared with the prior art, the beneficial effects of this utility model are: 1. In multiple straight pipe sections, the particle size of the adsorbent medium layer gradually decreases along the gas flow direction. After the yellow phosphorus tail gas enters the tower base from the inlet pipe, it passes through the adsorbent medium layer step by step from bottom to top. During this process, the phosphine in the yellow phosphorus tail gas is oxidized into phosphorus oxides and adsorbed on the surface of the adsorbent medium layer. The adsorbent medium layer adopts a gradient design with the pore size gradually decreasing from bottom to top, which can ensure sufficient contact between the yellow phosphorus tail gas and the adsorbent medium layer and improve the contact efficiency between the two. The flow guiding structure parameters are optimized through CFD simulation to make the residence time of the yellow phosphorus tail gas more concentrated, thereby improving the mass transfer rate and adsorption efficiency. 2. The number of straight pipe sections can be flexibly adjusted according to actual purification needs, which facilitates the assembly and maintenance of subsequent equipment. The detachable nature of the bolted connection allows for quick disassembly of the corresponding straight pipe section to replace the adsorbent medium layer when it is replaced in a certain straight pipe section. This greatly shortens the downtime of the equipment for maintenance, improves the overall purification efficiency, and eliminates the need for manual entry into the manhole for cleaning, ensuring thorough cleaning and improved safety. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is an exploded view of the structure of the tower base, tower body, and tower top of this utility model; Figure 3 This is an exploded view of a single straight pipe section in the tower body of this utility model; Figure 4 This is a cross-sectional structural diagram of the present invention; Figure 5 This is a schematic diagram of the regeneration pipeline of this utility model.

[0014] In the diagram: 1. Tower base; 2. Tower top; 21. Grid pressure plate; 3. Tower body; 31. Straight pipe section; 32. Connecting flange; 33. Support grid; 34. Wire mesh layer; 35. High-temperature sealing gasket; 36. Adsorbent medium layer; 37. Sampling tube; 4. Flange ring; 5. Inlet pipe; 6. Outlet pipe; 7. Regeneration pipeline; 71. Ring pipe; 72. Nozzle; 73. Delivery pipe. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0016] Please see Figure 1 , Figure 2 , Figure 3 and Figure 4This utility model provides a technical solution: a fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas, including a tower base 1, a tower top 2, an inlet pipe 5, and an outlet pipe 6. A tower body 3 is arranged between the tower base 1 and the tower top 2. Flange rings 4 are provided on the adjacent sides of the tower base 1 and the tower top 2 and the tower body 3. The tower base 1 and the tower top 2 are fixedly connected to the tower body 3 by bolts passing through the flange rings 4. A regeneration pipeline 7 is arranged inside the tower top 2. The tower body 3 includes multiple straight pipe sections 31. The top and bottom of the multiple straight pipe sections 31 are fixedly connected to the butt flanges 32. The multiple straight pipe sections 31 are vertically stacked and connected in a longitudinal direction. The bottom of the multiple straight pipe sections 31 is fixedly connected to the support grid 33. A wire mesh layer 34 is laid on the top of the support grid 33. Above the wire mesh layer 34... An adsorbent medium layer 36 is laid out, and the pore size of the supporting grid 33 is adapted to the adsorbent medium layer 36. In multiple straight pipe sections 31, the particle size of the adsorbent medium layer 36 gradually decreases along the gas flow direction. After the yellow phosphorus tail gas enters the tower base 1 from the inlet pipe 5, it passes through the adsorbent medium layer 36 step by step from bottom to top. During this process, the phosphine in the yellow phosphorus tail gas is oxidized into phosphorus oxides and adsorbed on the surface of the adsorbent medium layer 36. The adsorbent medium layer 36 adopts a gradient design with the pore size gradually decreasing from bottom to top, which can ensure that the yellow phosphorus tail gas and the adsorbent medium layer 36 are in full contact, improving the contact efficiency between the two. The flow guiding structure parameters are optimized through CFD simulation to make the residence time of the yellow phosphorus tail gas more concentrated, thereby improving the mass transfer rate and adsorption efficiency.

[0017] To prevent the adsorbent medium layer 36 from loosening or shifting under the impact of airflow, the mesh density of the wire mesh layer 34 is precisely designed to effectively support the adsorbent particles without obstructing gas flow. The support grid 33 above each stage compacts the adsorbent medium layer 36 below to form a stable bed structure, preventing local voids or flow deviations in the adsorbent medium layer 36 due to airflow disturbance. The adsorbent medium layer 36 uses one or more of activated carbon, zeolite, alumina, supported copper nitrate, ferric nitrate, and manganese nitrate.

[0018] The height of multiple straight pipe sections 31 is set according to the corresponding adsorbent medium layer 36. The required filling height of adsorbent medium layers 36 with different particle sizes is different. The bottom adsorbent medium layer 36 with larger particle size corresponds to a higher straight pipe section 31 height to ensure sufficient gas flow space and contact time, while the upper adsorbent medium layer 36 with smaller particle size corresponds to a relatively lower straight pipe section 31 height. While meeting the adsorption requirements, the overall height is reduced, realizing a compact design of the equipment structure. This makes the airflow distribution in each straight pipe section 31 more uniform and avoids airflow short-circuiting or stagnation caused by excessively large or small local spaces.

[0019] Multiple straight pipe sections 31 are fixedly connected by bolts through the connecting flanges 32 on adjacent sides. The number of straight pipe sections 31 can be flexibly adjusted according to actual purification needs, which facilitates the assembly and maintenance of subsequent equipment. The detachable nature of the bolt connection allows the corresponding straight pipe section 31 to be quickly disassembled and the adsorbent replaced when the adsorbent medium layer 36 in a certain straight pipe section 31 reaches saturation. This greatly shortens the downtime for equipment maintenance and improves the overall purification efficiency.

[0020] A groove is provided on the mating surface of the flange 32, and a high-temperature sealing gasket 35 is inserted inside the groove. The gasket is made of flexible graphite material that is resistant to phosphoric acid corrosion, and its thickness matches the depth of the groove. When the flange 32 is tightened with bolts, the high-temperature sealing gasket 35 is compressed and can completely fill the gap between the groove and the contact surface of the flange 32, effectively preventing yellow phosphorus tail gas from leaking from the connection during transportation. At the same time, it can withstand the high-temperature environment during the operation of the purification tower, avoid the decrease in sealing performance due to temperature changes, and ensure the safety and stability of the equipment during long-term operation.

[0021] A grid pressure plate 21 is fixedly installed at the bottom of the tower top 2. The grid pressure plate 21 is set against the top of the tower body 3. The grid pressure plate 21 is used to compact the uppermost adsorbent medium layer 36. It has excellent resistance to phosphoric acid corrosion and mechanical strength. It can maintain structural stability for a long time in the strong corrosive environment of yellow phosphorus tail gas, avoid support failure due to material deterioration, and further improve the overall service life and operational reliability of the purification tower.

[0022] Sampling tubes 37 are fixedly installed on the outer walls of multiple straight pipe sections 31, penetrating the straight pipe sections 31. The sampling tubes 37 are distributed along the height direction of the straight pipe sections 31, and corrosion-resistant valves are installed at their ports to facilitate operators to sample and analyze the adsorbent medium layer 36 and tail gas at different heights of the purification tower. The gas samples obtained through the sampling tubes 37 can be used to detect changes in the concentration of phosphorus content and other characteristic pollutants in the tail gas, providing data support for judging the adsorption efficiency and failure degree of the adsorbent medium layer 36, so as to adjust the process parameters or replace the adsorbent in a timely manner and ensure that the purification tower is always in the best dephosphorization working state.

[0023] Please see Figure 1 and Figure 5The regeneration pipeline 7 includes an annular pipe 71 fixedly installed on the inner wall of the tower top 2. The bottom of the annular pipe 71 is provided with nozzles 72 arranged in an annular shape at equal intervals facing the tower body 3. A conveying pipe 73 located outside the tower top 2 is fixedly connected to the outer wall of the annular pipe 71. By heating liquid water, water vapor, or a certain proportion of gas-water mixture to a certain temperature, the liquid water is introduced into the annular pipe 71 through the conveying pipe 73 and then into the purification tower through the nozzles 72 at the bottom, so that it comes into contact with the adsorbent medium layer 36. The adsorbed phosphorus oxides are discharged from the bed in the form of gaseous phosphoric acid gas, and the harmful substances that have not undergone chemical reaction flow out from the bed, so that the adsorbent medium layer 36 is regenerated.

[0024] The inlet pipe 5 and the outlet pipe 6 are fixedly connected to the outer walls of the tower base 1 and the tower top 2, respectively. The inlet end of the inlet pipe 5 is connected to the tail gas emission pipe of the yellow phosphorus production system, which is used to introduce the yellow phosphorus tail gas to be treated into the purification tower. The outlet end of the outlet pipe 6 is connected to the subsequent tail gas treatment or recovery system. The qualified tail gas after adsorption and purification is discharged through the outlet pipe 6.

[0025] Working principle: The height of the straight pipe section 31 is designed according to the characteristics of the adsorbent medium layer 36 and the specific dimensions of the purification tower. The wire mesh layer 34 is laid on top of the support grid 33 inside the straight pipe section 31, and the corresponding adsorbent medium layer 36 is added inside the straight pipe section 31. Multiple straight pipe sections 31 are connected by the connecting flanges 32 on adjacent sides and fixed with bolts to complete the assembly of the entire tower body 3. The tower body 3 is located between the tower base 1 and the tower top 2 and is connected to the flange ring 4 and fixed with bolts. After the yellow phosphorus tail gas is heated to a certain temperature, it enters the tower base 1 from the bottom through the inlet pipe 5. The gas passes through the adsorbent medium layer 36 in the straight pipe section 31 in stages. During this process, phosphine in the yellow phosphorus tail gas is oxidized into phosphorus oxide and adsorbed on the surface of the adsorbent medium layer 36. The purified yellow phosphorus tail gas is then sent downstream through the outlet pipe 6. The gradient setting of the adsorbent medium layer 36 with gradually decreasing pore size from bottom to top enables the yellow phosphorus tail gas to fully contact the adsorbent medium layer 36. The gradient filling improves the contact efficiency between the yellow phosphorus tail gas and the adsorbent medium layer 36. The flow guiding structure parameters are optimized by CFD simulation to make the residence time of the yellow phosphorus tail gas more concentrated, thereby improving the mass transfer rate and adsorption efficiency. The adsorption status of each adsorbent medium layer 36 can be monitored through sampling tube 37. When the purification tower is saturated with adsorption, adsorption stops. Liquid water, water vapor, or a certain proportion of gas-water mixture is heated to a certain temperature and introduced into the adsorbent medium layer 36 in the purification tower through delivery pipe 73. Phosphorus oxide is generated and discharged in the form of gaseous phosphoric acid gas. Hydrogen sulfide and carbonyl sulfide flow out from the purification tower bed without any chemical reaction, so that the adsorbent medium layer 36 is regenerated. By adopting a modular design, when a section of the adsorbent medium layer 36 needs to be replaced after long-term use, the bolts connecting the upper and lower sides of the corresponding straight pipe section 31 to the adjacent straight pipe section 31 are removed to separate it independently. The upper straight pipe section 31 is then separated by hoisting from the top of the tower 2. The straight pipe section 31 that needs to be replaced is then lifted down, ensuring a thorough replacement and improving safety. This facilitates the rapid replacement of the adsorbent medium layer 36. The above is the working process of the entire device. Any content not described in detail in this specification belongs to the prior art known to those skilled in the art.

[0026] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas, comprising a tower base (1), a tower top (2), an inlet pipe (5), and an outlet pipe (6), characterized in that: A tower body (3) is provided between the tower base (1) and the tower top (2). A flange ring (4) is provided on the adjacent side of the tower base (1), the tower top (2) and the tower body (3). The tower base (1) and the tower top (2) are fixedly connected to the tower body (3) by bolts passing through the flange ring (4). A regeneration pipeline (7) is provided inside the tower top (2). The tower body (3) includes multiple straight pipe sections (31), and the top and bottom of the multiple straight pipe sections (31) are fixedly connected with connecting flanges (32). The multiple straight pipe sections (31) are vertically stacked and connected in the longitudinal direction. The bottom of the multiple straight pipe sections (31) is fixedly connected with a support grid (33). The top of the support grid (33) is covered with a wire mesh layer (34). The top of the wire mesh layer (34) is covered with an adsorbent medium layer (36). The adsorbent medium layer (36) in the multiple straight pipe sections (31) is set with the particle size gradually decreasing along the gas flow direction.

2. The fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas according to claim 1, characterized in that: The height of the multiple straight pipe sections (31) is set according to the corresponding adsorbent medium layer (36).

3. A fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas according to claim 1, characterized in that: Multiple straight pipe sections (31) are fixedly connected by bolts through the mating flanges (32) on adjacent sides.

4. A fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas according to claim 3, characterized in that: The mating surface of the mating flange (32) is provided with a groove, and a high-temperature sealing gasket (35) is inserted inside the groove.

5. A fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas according to claim 1, characterized in that: A grid pressure plate (21) is fixedly installed at the bottom of the tower top (2), and the grid pressure plate (21) is set above the tower body (3).

6. A fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas according to claim 5, characterized in that: Sampling tubes (37) that penetrate the straight pipe sections (31) are fixedly installed on the outer walls of the multiple straight pipe sections (31).

7. A fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas according to claim 5, characterized in that: The regeneration pipeline (7) includes an annular pipe (71) fixedly installed on the inner wall of the tower top (2). The bottom of the annular pipe (71) is provided with nozzles (72) equidistantly arranged in an annular shape facing the tower body (3). A delivery pipe (73) located outside the tower top (2) is fixedly connected to the outer wall of the annular pipe (71).

8. A fixed-bed purification tower for dephosphorization of yellow phosphorus tail gas according to claim 1, characterized in that: The air inlet pipe (5) and the air outlet pipe (6) are fixedly connected to the outer walls of the tower base (1) and the tower top (2), respectively.

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