Ammonia delivery system with in-tower impurity removal device for ammonia stripping tower and application method thereof

Abstract

The application provides an ammonia tower ammonia gas conveying system with an in-tower impurity removal device and an application method thereof, and belongs to the technical field of ammonia towers. The system comprises a plurality of ammonia towers. The top of each ammonia tower is connected with an ammonia gas pipeline. Each ammonia gas pipeline is connected with an ammonia gas condensing cooler. An in-tower impurity removal device is arranged in each ammonia tower. The in-tower impurity removal device comprises a filter plate and a scraper. The filter plate is installed at the bottom of the ammonia tower. The scraper is rotatably arranged at the top of the filter plate. An impurity outlet is formed in one side of the center of the filter plate. The impurity outlet is connected with an impurity collection box. The single-tower single-path independent gas conveying structure, the in-tower source impurity removal device and the corrosion-resistant and easy-to-maintain pipeline structure can solve the problems of high shutdown risk of the shared gas conveying main pipe and serious pipeline corrosion and blockage, significantly improve the production continuity, reduce the operation and maintenance load and the operation safety risk, and ensure the long-period stable operation of the ammonia gas conveying system.

Description

Technical Field

[0001] This invention relates to the field of ammonia stripping tower technology, and in particular to an ammonia gas conveying system for an ammonia stripping tower with an in-tower impurity removal device and its application method. Background Technology

[0002] In the recovery of coking chemical products, the ammonia stripping process is used to treat the residual ammonia water and recover ammonia gas. The ammonia gas produced at the top of the tower is sent to the condensation and cooling unit through the pipeline to produce concentrated ammonia water. The parallel operation of multiple ammonia stripping towers is a typical configuration for large-scale production. The operational stability of the ammonia gas transmission pipeline directly affects the production continuity and safety of the entire system.

[0003] In the prior art, for example, Chinese patent application CN119143152A discloses a method for condensing and cooling ammonia gas in an ammonia stripping tower. This method reduces system corrosion and improves heat exchange efficiency by replacing the double-spiral plate heat exchanger, setting up parallel ammonia condensers as backups for each other, and upgrading the material and diameter of the concentrated ammonia water pipeline. However, this solution only optimizes the concentrated ammonia water pipeline after condensation, and the gas phase transmission structure at the top of the tower is unreasonable. When multiple towers share a common gas transmission main, a single-section leak can cause the entire system to shut down.

[0004] For example, Chinese patent CN119680220A discloses an ammonia stripping device and a method for improving the operational quality of the ammonia stripping process. It employs a process of top-of-tower acid removal, side-stream ammonia collection, and naphthalene removal and impurity removal in a post-tower adsorption tower to reduce corrosive factors and improve the quality of concentrated ammonia water. However, it uses a single-tower, single-path gas transmission architecture, and impurity removal relies solely on the post-tower adsorption unit, which cannot reduce impurities entering the gas transmission pipeline from the source within the tower, making it difficult to meet the requirements of long-term stable production. Summary of the Invention

[0005] The purpose of this invention is to overcome the technical defects in the existing technology, such as the ease with which a shared gas transmission main can lead to a complete shutdown, the high risk of corrosion and maintenance of gas phase pipelines, and the insufficient source control of impurities after the tower. The invention provides an ammonia gas transmission system with an in-tower impurity removal device and its application method.

[0006] In a first aspect, the present invention provides an ammonia conveying system with an in-tower impurity removal device for ammonia stripping towers to solve the above-mentioned technical problems. The system includes multiple ammonia stripping towers; each of the multiple ammonia stripping towers is connected to an ammonia gas pipeline at its top, and each ammonia gas pipeline is connected to an ammonia gas condenser / cooler; an in-tower impurity removal device is installed inside each ammonia stripping tower, including a filter plate and a scraper; the filter plate is installed at the bottom of the ammonia stripping tower, and the scraper is rotatably mounted on top of the filter plate; an impurity outlet is provided on one side of the center of the filter plate, and the impurity outlet is connected to an impurity collection box installed at the bottom of the filter plate; a drive motor is installed on the outer wall of the ammonia stripping tower, and the drive motor is connected to the scraper via a transmission shaft assembly assembled inside the ammonia stripping tower. The rotation of the scraper can scrape the impurities filtered out by the filter plate through the impurity outlet to the impurity collection box; multiple water filtration holes are provided at the bottom of the impurity collection box, and an impurity discharge manhole is provided on the outer wall of the ammonia stripping tower, communicating with the end of the impurity collection box. The impurity discharge manhole can discharge the impurities collected inside the impurity collection box.

[0007] This invention, through the aforementioned independent gas transmission architecture design, enables the shutdown of only the corresponding tower in the event of a single pipeline failure, without requiring a complete production shutdown. This addresses the drawback of a single leak in a shared gas transmission main causing a complete shutdown, thus ensuring production continuity. Furthermore, the tower's source interception of impurities reduces blockages and corrosion caused by impurities entering the pipeline with the gas phase. Compared to post-tower adsorption and impurity removal processes, this proactive approach effectively reduces the maintenance load on subsequent pipelines and equipment.

[0008] A further improvement of the present invention is that the drive shaft assembly includes a horizontal rotating shaft and a vertical rotating shaft. The horizontal rotating shaft is rotatably disposed inside the impurity collection box, and the vertical rotating shaft is rotatably disposed at the center of the filter plate. The top of the vertical rotating shaft extends above the filter plate and is fixedly connected to the center of the scraper. The bottom of the vertical rotating shaft extends below the filter plate. The end of the horizontal rotating shaft away from the center of the filter plate extends to the outside of the ammonia stripping tower and is connected to the drive motor. The end of the horizontal rotating shaft near the center of the filter plate passes through the side wall of the impurity collection box and is connected to the bottom of the vertical rotating shaft through a gear mechanism.

[0009] This invention avoids the high temperature and humidity conditions at the top of the tower through a side-mounted transmission layout design, thus improving the service life of the motor; the vertical shaft is directly connected to the center of the scraper, resulting in a short transmission path, uniform cleaning torque, and better operational stability than the top-mounted transmission structure; the shared power source design simplifies the internal structure of the tower and reduces equipment modification costs.

[0010] A further improvement of the present invention is that the gear mechanism includes a first bevel gear and a second bevel gear, the first bevel gear being mounted on the bottom of the vertical rotating shaft, and the second bevel gear being mounted on the end of the horizontal rotating shaft near the center of the filter plate, wherein the first bevel gear and the second bevel gear are meshed together.

[0011] The aforementioned bevel gear transmission has strong load-bearing capacity and stable transmission ratio, making it suitable for the humid and ammonia-containing corrosive environment inside the tower. It also has high reversing transmission efficiency, which can effectively reduce power loss, ensure the speed stability of the scraper cleaning process, and reduce the frequency of transmission failures.

[0012] A further improvement of the present invention is that a reinforcing bracket is provided below the vertical rotating shaft, the reinforcing bracket is fixedly connected to the inner wall of the ammonia stripping tower, and the bottom end of the vertical rotating shaft is rotatably connected to the center of the reinforcing bracket.

[0013] The present invention can effectively counteract the radial sway force when the scraper rotates by the above-mentioned dual-support design, avoid bending deformation of the rotating shaft after long-term operation, reduce the risk of transmission jamming and sealing failure, and improve the operational reliability and service life of the entire impurity removal device.

[0014] A further improvement of the present invention is that the outer wall of the horizontal rotating shaft is provided with helical blades, which can discharge impurities inside the impurity collection box through the impurity discharge manhole.

[0015] The present invention, through the above-mentioned structural design, can share the driving power of the scraper, without the need to add an additional impurity discharge power unit, and can realize the continuous automatic discharge of impurities, avoid the accumulation and caking of impurities in the collection box, greatly reduce the frequency of manual tower opening and cleaning, and reduce operation and maintenance costs and downtime.

[0016] A further improvement of the present invention is that the scraper has an S-shaped structure, which, when rotated, can push the impurities attached to the vertical rotating shaft outwards along the scraper surface and fall off.

[0017] The present invention solves the problem of material accumulation and jamming at the central shaft of conventional straight scrapers through the above design, and achieves cleaning of the filter plate surface without dead corners; at the same time, the curved structure can reduce the rotation resistance of the scraper, reduce the motor load, and make the equipment run more smoothly.

[0018] A further improvement of the present invention is that the impurity outlet and the impurity collection box are elongated structures that are adapted to each other.

[0019] The present invention, through the above-mentioned elongated nozzle design, can increase the passing area of ​​impurities falling, avoid viscous heavy impurities from clogging the outlet, expand the effective range of impurity collection, increase the cleaning throughput per unit time, adapt to continuous production conditions with high impurity load, and reduce the probability of outlet blockage failure.

[0020] A further improvement of the present invention is that the ammonia pipeline is arranged vertically outside the ammonia stripping tower, and both ends of the ammonia pipeline are connected to the top of the ammonia stripping tower and the ammonia condenser via elbow fittings; the elbow fittings are made of PTFE-lined material, and the elbow fittings are connected to the ammonia pipeline via loose flanges.

[0021] The aforementioned PTFE-lined elbows and fittings can resist the erosion and corrosion of ammonia-containing gaseous media, significantly extending the service life of weak parts of the elbows. The loose flange connection eliminates the need for hot welding and overall pipeline replacement when replacing elbows, effectively solving the shortcomings of existing welded elbows, such as rapid corrosion, high risk of hot work during maintenance, and long downtime, significantly reducing operation and maintenance safety risks and maintenance costs.

[0022] A further improvement of the present invention is that the ammonia pipeline is supported and fixed by multiple sets of pipe rack assemblies, the pipe rack assemblies including riser guide supports and pipeline fixing blocks, and the multiple sets of pipe rack assemblies are arranged at intervals along the axial direction of the ammonia pipeline.

[0023] The present invention, through the above-mentioned combined support structure design, can adaptively absorb the thermal expansion and contraction deformation of the pipeline caused by temperature changes, avoid stress concentration leading to weld cracking and leakage, and effectively reduce the risk of pipeline leakage and improve the stability of the gas transmission system during long-term operation compared with traditional fixed pipe supports.

[0024] Secondly, the present invention also provides an application method for an ammonia conveying system with an in-tower impurity removal device, comprising the following steps: S1. The ammonia gas produced by each of the ammonia stripping towers is transported to the corresponding ammonia condenser via independent ammonia gas pipelines; S2. When the liquid phase in the ammonia stripping tower flows through the bottom filter plate, heavy oil and ammonium salt impurities are trapped by the filter plate, and the purified gas phase rises into the ammonia pipeline. S3. The drive motor drives the scraper to rotate via the transmission shaft assembly, scraping the trapped impurities into the impurity collection box through the impurity outlet; S4. After the impurities are drained through the filter holes, they are discharged through the impurity discharge manhole.

[0025] This invention improves production continuity from a system architecture perspective by using the aforementioned single-tower, single-path independent gas transmission mode, thus solving the pain point of a complete shutdown of a shared main pipeline. The source filtration and impurity control within the tower is more advanced, which can reduce subsequent pipeline blockage and corrosion. The mechanical scraping and draining process is continuous, which can maintain stable filtration flux. The entire method can achieve long-term stable operation of the ammonia gas transmission system, effectively reducing the frequency of operation and maintenance and safety risks.

[0026] As can be seen from the above technical solutions, the beneficial effects of the present invention are: 1. This invention adopts a single-tower, single-path independent gas transmission architecture, with each ammonia stripping tower equipped with an independent ammonia pipeline. If a single pipeline fails, only the corresponding tower needs to be shut down, completely avoiding the risk of a single-point leak in the shared gas transmission main pipeline causing a complete shutdown and significantly improving the continuity of production operations.

[0027] 2. This invention uses an in-tower impurity removal device to intercept heavy oil and ammonium salt impurities at the source, reducing the blockage and corrosion caused by impurities entering the conveying pipeline with the gas phase. Compared with existing post-tower adsorption impurity removal, the impurity removal and control is carried out in advance, which can effectively reduce the maintenance load of subsequent pipelines and equipment.

[0028] 3. This invention alleviates pipeline corrosion and thermal stress cracking problems through PTFE-lined corrosion-resistant elbows, loose flange connections, and combined pipe rack design. Maintenance and replacement do not require hot work, significantly reducing operation and maintenance safety risks and downtime costs, and ensuring long-term stable operation of the system. Attached Figure Description

[0029] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a structural schematic diagram of a specific embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of the internal structure of the ammonia stripping tower according to a specific embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of the gear mechanism according to a specific embodiment of the present invention.

[0033] Figure 4 This is a schematic diagram of the scraper structure according to a specific embodiment of the present invention.

[0034] In the diagram: 1. Ammonia stripping tower; 2. Ammonia pipeline; 201. Elbow fitting; 202. Riser guide support; 3. Filter plate; 301. Impurity outlet; 4. Scraper; 5. Horizontal rotating shaft; 501. Spiral blade; 6. Impurity collection box; 601. Water filter hole; 602. Impurity discharge manhole; 7. Vertical rotating shaft; 8. Drive motor; 9. First bevel gear; 10. Second bevel gear; 11. Reinforcing support. Detailed Implementation

[0035] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0036] Example 1: Refer to Figure 1-4This embodiment provides an ammonia gas conveying system with an in-tower impurity removal device, including multiple ammonia stripping towers 1; the tops of the multiple ammonia stripping towers 1 are respectively connected to ammonia gas pipelines 2, and each ammonia gas pipeline 2 is respectively connected to an ammonia gas condenser / cooler; an in-tower impurity removal device is installed inside the ammonia stripping tower 1, the in-tower impurity removal device includes a filter plate 3 and a scraper 4; the filter plate 3 is installed at the bottom inside the ammonia stripping tower 1, and the scraper 4 is rotatably installed on the top of the filter plate 3; an impurity outlet 301 is opened on one side of the center of the filter plate 3, and the impurity outlet 301 is connected to an ammonia gas condenser / cooler installed inside the tower 1. The impurity collection box 6 is located at the bottom of the filter plate 3; a drive motor 8 is installed on the outer wall of the ammonia stripping tower 1, and the drive motor 8 is connected to the scraper 4 through a transmission shaft assembly assembled inside the ammonia stripping tower 1. The rotation of the scraper 4 can scrape the impurities filtered out by the filter plate 3 through the impurity outlet 301 into the impurity collection box 6; multiple water filtering holes 601 are opened at the bottom of the impurity collection box 6, and an impurity discharge manhole 602 communicating with the end of the impurity collection box 6 is provided on the outer wall of the ammonia stripping tower 1. The impurity discharge manhole 602 can discharge the impurities collected inside the impurity collection box 6.

[0037] The ammonia produced at the top of multiple ammonia stripping towers 1 is transported to the corresponding ammonia condenser through their respective independent ammonia pipelines 2, forming an independent gas transmission structure with one tower and one path. When the liquid material in the ammonia stripping tower 1 flows through the bottom filter plate 3, impurities such as heavy oil and ammonium salts are intercepted, and the purified gas phase rises into the ammonia pipeline 2. The drive motor 8 drives the scraper 4 to rotate along the top surface of the filter plate 3 through the transmission shaft assembly, and scrapes the intercepted impurities through the impurity outlet 301 to the impurity collection box 6 below for temporary storage. After the impurities are drained of liquid phase through the water filter hole 601, they can be discharged periodically through the impurity discharge manhole 602.

[0038] This invention, through the aforementioned independent gas transmission architecture design, enables the shutdown of only the corresponding tower in the event of a single pipeline failure, without requiring a complete production shutdown. This addresses the drawback of a single leak in a shared gas transmission main causing a complete shutdown, thus ensuring production continuity. Furthermore, the tower's source interception of impurities reduces blockages and corrosion caused by impurities entering the pipeline with the gas phase. Compared to post-tower adsorption and impurity removal processes, this proactive approach effectively reduces the maintenance load on subsequent pipelines and equipment.

[0039] Specifically, refer to Figure 2 and 4The drive shaft assembly includes a horizontal rotating shaft 5 and a vertical rotating shaft 7. The horizontal rotating shaft 5 is rotatably disposed inside the impurity collection box 6, and the vertical rotating shaft 7 is rotatably disposed at the center of the filter plate 3. The top of the vertical rotating shaft 7 extends above the filter plate 3 and is fixedly connected to the center of the scraper 4. The bottom of the vertical rotating shaft 7 extends below the filter plate 3. The end of the horizontal rotating shaft 5 away from the center of the filter plate 3 extends to the outside of the ammonia stripping tower 1 and is connected to the drive motor 8. The end of the horizontal rotating shaft 5 near the center of the filter plate 3 passes through the side wall of the impurity collection box 6 and is connected to the bottom of the vertical rotating shaft 7 through a gear mechanism.

[0040] The drive shaft assembly adopts a split reversing design of horizontal shaft 5 and vertical shaft 7. The drive motor 8 is arranged on the side wall of the tower and drives the horizontal shaft 5 to rotate. The power is transmitted to the vertical shaft 7 through the gear mechanism, which in turn drives the scraper 4 to rotate coaxially. The horizontal shaft 5 passes through the impurity collection box 6. One power source provides power for scraper cleaning and subsequent impurity discharge.

[0041] This invention avoids the high temperature and humidity conditions at the top of the tower through a side-mounted transmission layout design, thus improving the service life of the motor; the vertical shaft is directly connected to the center of the scraper, resulting in a short transmission path, uniform cleaning torque, and better operational stability than the top-mounted transmission structure; the shared power source design simplifies the internal structure of the tower and reduces equipment modification costs.

[0042] Specifically, refer to Figure 3 The gear mechanism includes a first bevel gear 9 and a second bevel gear 10. The first bevel gear 9 is installed at the bottom of the vertical rotating shaft 7, and the second bevel gear 10 is installed at one end of the horizontal rotating shaft 5 near the center of the filter plate 3. The first bevel gear 9 and the second bevel gear 10 are meshed together.

[0043] The gear mechanism adopts a bevel gear transmission structure in which the first bevel gear 9 and the second bevel gear 10 mesh. The horizontal rotating shaft 5 drives the second bevel gear 10 to rotate, and the torque in the horizontal direction is reversed and transmitted to the first bevel gear 9 in the vertical direction through meshing transmission, thereby driving the vertical rotating shaft 7 to rotate.

[0044] The aforementioned bevel gear transmission has strong load-bearing capacity and stable transmission ratio, making it suitable for the humid and ammonia-containing corrosive environment inside the tower. It also has high reversing transmission efficiency, which can effectively reduce power loss, ensure the speed stability of the scraper cleaning process, and reduce the frequency of transmission failures.

[0045] Specifically, refer to Figure 2 A reinforcing bracket 11 is provided below the vertical rotating shaft 7. The reinforcing bracket 11 is fixedly connected to the inner wall of the ammonia stripping tower 1. The bottom end of the vertical rotating shaft 7 is rotatably connected to the center of the reinforcing bracket 11.

[0046] The reinforcing bracket 11 is fixed to the inner wall of the ammonia stripping tower 1, forming a rotational support for the bottom end of the vertical rotating shaft 7. Together with the rotating shaft support point at the filter plate 3, it forms a double-support constraint structure, which together limits the rotation path of the vertical rotating shaft 7.

[0047] The present invention can effectively counteract the radial sway force when the scraper 4 rotates by the above-mentioned dual-support design, avoid bending deformation of the rotating shaft after long-term operation, reduce the risk of transmission jamming and sealing failure, and improve the operational reliability and service life of the entire impurity removal device.

[0048] Specifically, refer to Figure 4 The outer wall of the horizontal rotating shaft 5 is provided with a spiral blade 501, which can discharge impurities inside the impurity collection box 6 through the impurity discharge manhole 602.

[0049] The outer wall of the horizontal rotating shaft 5 is provided with spiral blades 501. When the horizontal rotating shaft 5 rotates synchronously with the drive motor 8, the spiral blades 501 push the impurities deposited in the impurity collection box 6 along the axial direction and continuously transport them to the impurity discharge manhole 602 for discharge.

[0050] The present invention, through the above-mentioned structural design, can share the driving power of the scraper, without the need to add an additional impurity discharge power unit, and can realize the continuous automatic discharge of impurities, avoid the accumulation and caking of impurities in the collection box, greatly reduce the frequency of manual tower opening and cleaning, and reduce operation and maintenance costs and downtime.

[0051] Specifically, refer to Figure 4 The scraper 4 has an S-shaped structure, which can push the impurities attached to the vertical rotating shaft 7 outwards along the surface of the scraper 4 and fall off when it rotates.

[0052] The scraper 4 adopts an S-shaped curved surface structure. As it rotates with the vertical shaft 7, the curved surface facing the material generates an outward radial thrust on the impurities at the root of the central shaft, causing the impurities attached to the root of the vertical shaft 7 to be pushed and detached along the surface of the scraper 4.

[0053] The present invention solves the problem of material accumulation and jamming at the central shaft of conventional straight scrapers through the above design, and achieves thorough cleaning of the three filter plates without dead angles; at the same time, the curved structure can reduce the rotation resistance of the scraper, reduce the motor load, and make the equipment run more smoothly.

[0054] Specifically, refer to Figure 4 The impurity outlet 301 and the impurity collection box 6 are elongated structures that are adapted to each other.

[0055] Both the impurity outlet 301 and the impurity collection box 6 adopt an elongated structure that extends radially along the filter plate 3. Their dimensions are compatible with each other and perfectly match the sweeping path of the rotating scraper 4.

[0056] The present invention, through the above-mentioned elongated nozzle design, can increase the passing area of ​​impurities falling, avoid viscous heavy impurities from clogging the outlet, expand the effective range of impurity collection, increase the cleaning throughput per unit time, adapt to continuous production conditions with high impurity load, and reduce the probability of outlet blockage failure.

[0057] Specifically, refer to Figure 1 The ammonia pipeline 2 is vertically arranged outside the ammonia stripping tower 1. Both ends of the ammonia pipeline 2 are connected to the top of the ammonia stripping tower 1 and the ammonia condenser via elbow fittings 201. The elbow fittings 201 are made of PTFE lined material and are connected to the ammonia pipeline 2 via loose flanges.

[0058] Ammonia pipeline 2 is vertically arranged outside ammonia stripping tower 1, and the pipeline turns at both ends through elbow fittings 201; elbow fittings 201 are made of PTFE-lined material to isolate the medium from the metal substrate, and the elbow and pipeline are detachably connected by loose flanges.

[0059] The aforementioned PTFE-lined elbow fitting 201 can resist the erosion and corrosion of ammonia-containing gaseous media, significantly extending the service life of weak parts of the elbow; the loose flange connection eliminates the need for hot welding and overall pipeline replacement when replacing the elbow, specifically addressing the shortcomings of existing welded elbows such as rapid corrosion, high risk of hot work during maintenance, and long downtime, significantly reducing operation and maintenance safety risks and maintenance costs.

[0060] Specifically, refer to Figure 1 The ammonia pipeline 2 is supported and fixed by multiple sets of pipe rack assemblies. The pipe rack assemblies include riser guide supports 202 and pipeline fixing blocks, and the multiple sets of pipe rack assemblies are arranged at intervals along the axial direction of the ammonia pipeline 2.

[0061] The ammonia pipeline 2 is supported by multiple sets of pipe rack assemblies arranged at intervals along the axial direction. Among them, the pipeline fixed pier bears the main vertical load and axial positioning of the pipeline, while the riser guide support 202 restricts the radial displacement of the pipeline and releases the space for axial thermal expansion deformation.

[0062] The present invention, through the above-mentioned combined support structure design, can adaptively absorb the thermal expansion and contraction deformation of the pipeline caused by temperature changes, avoid stress concentration leading to weld cracking and leakage, and effectively reduce the risk of pipeline leakage and improve the stability of the gas transmission system during long-term operation compared with traditional fixed pipe supports.

[0063] Example 2: Based on Example 1, this example provides an application method for an ammonia conveying system with an in-tower impurity removal device, including the following steps: S1. The ammonia gas produced by each of the ammonia stripping towers 1 is transported to the corresponding ammonia condenser via an independent ammonia gas pipeline 2; S2. When the liquid phase in the ammonia stripping tower 1 flows through the bottom filter plate 3, heavy oil and ammonium salt impurities are intercepted by the filter plate 3, and the purified gas phase rises into the ammonia pipeline 2. S3. The drive motor 8 drives the scraper 4 to rotate via the transmission shaft assembly, scraping the intercepted impurities into the impurity collection box 6 through the impurity outlet 301; S4. After the impurities are drained through the filter hole 601, they are discharged through the impurity discharge manhole 602.

[0064] In step S1, the ammonia produced by each ammonia stripping tower 1 is transported separately through independent ammonia pipelines 2; in step S2, the liquid phase in the ammonia stripping tower 1 is filtered by the bottom filter plate 3 to trap impurities, and the purified gas phase is transported upwards; in step S3, the drive motor 8 drives the scraper 4 to rotate through the transmission shaft assembly, scraping the impurities into the impurity collection box 6; in step S4, the impurities are drained through the water filter hole 601 and discharged through the impurity discharge manhole 602.

[0065] This invention improves production continuity from a system architecture perspective by using the aforementioned single-tower, single-path independent gas transmission mode, thus solving the pain point of a complete shutdown of a shared main pipeline. The source filtration and impurity control within the tower is more advanced, which can reduce subsequent pipeline blockage and corrosion. The mechanical scraping and draining process is continuous, which can maintain stable filtration flux. The entire method can achieve long-term stable operation of the ammonia gas transmission system, effectively reducing the frequency of operation and maintenance and safety risks.

[0066] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An ammonia gas conveying system for an ammonia stripping tower with an in-tower impurity removal device, comprising multiple ammonia stripping towers (1), characterized in that, The tops of the multiple ammonia stripping towers (1) are respectively connected to ammonia gas pipelines (2), and each ammonia gas pipeline (2) is respectively connected to an ammonia gas condenser; the interior of the ammonia stripping tower (1) is equipped with an internal impurity removal device, which includes a filter plate (3) and a scraper (4); the filter plate (3) is installed at the bottom of the ammonia stripping tower (1), and the scraper (4) is rotatably mounted on the top of the filter plate (3); an impurity outlet (301) is opened on one side of the center of the filter plate (3), and the impurity outlet (301) is provided on the top side of the filter plate (3). The impurity outlet (301) is connected to an impurity collection box (6) installed at the bottom of the filter plate (3); a drive motor (8) is installed on the outer wall of the ammonia stripping tower (1), and the drive motor (8) is connected to the scraper (4) through a drive shaft assembly assembled inside the ammonia stripping tower (1); multiple water filter holes (601) are opened at the bottom of the impurity collection box (6), and an impurity discharge manhole (602) connected to the end of the impurity collection box (6) is provided on the outer wall of the ammonia stripping tower (1).

2. The ammonia gas conveying system for an ammonia stripping tower with an in-tower impurity removal device according to claim 1, characterized in that, The drive shaft assembly includes a horizontal rotating shaft (5) and a vertical rotating shaft (7). The horizontal rotating shaft (5) is rotatably disposed inside the impurity collection box (6), and the vertical rotating shaft (7) is rotatably disposed at the center of the filter plate (3). The top of the vertical rotating shaft (7) extends above the filter plate (3) and is fixedly connected to the center of the scraper (4). The bottom of the vertical rotating shaft (7) extends below the filter plate (3). The end of the horizontal rotating shaft (5) away from the center of the filter plate (3) extends to the outside of the ammonia stripping tower (1) and is connected to the drive motor (8). The end of the horizontal rotating shaft (5) near the center of the filter plate (3) passes through the side wall of the impurity collection box (6) and is connected to the bottom of the vertical rotating shaft (7) through a gear mechanism.

3. The ammonia gas conveying system for an ammonia stripping tower with an in-tower impurity removal device according to claim 2, characterized in that, The gear mechanism includes a first bevel gear (9) and a second bevel gear (10). The first bevel gear (9) is installed at the bottom of the vertical rotating shaft (7), and the second bevel gear (10) is installed at one end of the horizontal rotating shaft (5) near the center of the filter plate (3). The first bevel gear (9) and the second bevel gear (10) are meshed together.

4. The ammonia gas conveying system for an ammonia stripping tower with an in-tower impurity removal device according to claim 3, characterized in that, A reinforcing bracket (11) is provided below the vertical rotating shaft (7). The reinforcing bracket (11) is fixedly connected to the inner wall of the ammonia stripping tower (1). The bottom end of the vertical rotating shaft (7) is rotatably connected to the center of the reinforcing bracket (11).

5. The ammonia gas conveying system for an ammonia stripping tower with an in-tower impurity removal device according to claim 2, characterized in that, The outer wall of the horizontal rotating shaft (5) is provided with a helical blade (501).

6. The ammonia gas conveying system for an ammonia stripping tower with an in-tower impurity removal device according to claim 2, characterized in that, The scraper (4) has an S-shaped structure.

7. The ammonia gas conveying system for an ammonia stripping tower with an in-tower impurity removal device according to claim 1, characterized in that, The impurity outlet (301) and the impurity collection box (6) are elongated structures that are compatible with each other.

8. The ammonia gas conveying system for an ammonia stripping tower with an in-tower impurity removal device according to claim 1, characterized in that, The ammonia pipeline (2) is arranged vertically outside the ammonia stripping tower (1). Both ends of the ammonia pipeline (2) are connected to the top of the ammonia stripping tower (1) and the ammonia condenser via elbow fittings (201). The elbow fittings (201) are made of PTFE lined material, and the elbow fittings (201) are connected to the ammonia pipeline (2) via loose flanges.

9. The ammonia gas conveying system for an ammonia stripping tower with an in-tower impurity removal device according to claim 8, characterized in that, The ammonia pipeline (2) is supported and fixed by multiple sets of pipe rack assemblies, which include riser guide supports (202) and pipeline fixing blocks, and the multiple sets of pipe rack assemblies are arranged at intervals along the axial direction of the ammonia pipeline (2).

10. The application method of the ammonia conveying system with an in-tower impurity removal device according to any one of claims 1-9, characterized in that, Includes the following steps: S1. The ammonia gas produced by each of the ammonia stripping towers (1) is transported to the corresponding ammonia condenser via an independent ammonia gas pipeline (2); S2. When the liquid phase in the ammonia stripping tower (1) flows through the bottom filter plate (3), heavy oil and ammonium salt impurities are intercepted by the filter plate (3), and the purified gas phase rises into the ammonia pipeline (2). S3. The drive motor (8) drives the scraper (4) to rotate via the transmission shaft assembly, and scrapes the intercepted impurities into the impurity collection box (6) through the impurity outlet (301). S4. After the impurities are drained through the filter hole (601), they are discharged through the impurity discharge manhole (602).

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