Urea prilling tower with anti-wall-sticking and scale-removing devices

Abstract

The application discloses a wall-sticking-preventing urea prilling tower with scale-removing device, and relates to the technical field of urea prilling equipment. The prilling tower comprises a tower body and a filter unit at the top, and the innovation is that an automatic scale-removing device is arranged below the filter unit. The device comprises a rotatable rotating carrier cylinder, the carrier cylinder is fixed with a vertical sliding rod through a connecting plate, a counterweight shovel block is arranged on the sliding rod in a limited sliding mode, a sealing box is arranged below the connecting plate, and a tower wall information acquisition module for detecting tower wall scaling is arranged in the sealing box. During scale removal, the rotating carrier cylinder drives the acquisition module to rotate and scan, a control system drives a lifting mechanism to release the counterweight shovel block according to the scanning result, so that the counterweight shovel block slides down along the sliding rod and removes scaling by gravity. The vertical guide structure solves the problem of insufficient rigidity of the scale remover of the high and large tower body, realizes the intelligent detection and the scale-removing mode of gravity and impact force combination, and has the advantages of good scale-removing effect, high automation degree, reliable operation and the like, and can effectively guarantee the long-term stable operation of the urea prilling tower.

Description

Technical Field

[0001] This invention relates to the field of urea granulation equipment technology, and specifically discloses an anti-sticking urea granulation tower equipped with a scale removal device. Background Technology

[0002] Urea, as an important nitrogen fertilizer and chemical raw material, relies heavily on granulation in its production process. Tower granulation is widely used due to its simplicity, high capacity, and uniform particle shape. In this process, molten urea is sprayed from nozzles at the top of the granulation tower, where it comes into counter-current contact with rising cold air at the bottom, cooling and solidifying into granules. However, during production, molten urea droplets or dust easily adhere to the inner wall of the granulation tower, forming and accumulating a scale layer, resulting in a "wall-sticking" phenomenon. This wall-sticking not only reduces the effective tower diameter, affecting particle cooling and descent trajectory, leading to uneven particle size and higher temperatures, but also poses a risk of large scale deposits accidentally detaching and damaging the conveying equipment at the bottom of the tower, causing unplanned shutdowns and safety accidents.

[0003] Currently, methods for preventing wall adhesion in granulation towers are mainly divided into two categories: passive prevention and active cleaning. Passive prevention measures include optimizing nozzle atomization, controlling the temperature and humidity of the air entering the tower, and spraying anti-adhesion coatings on the tower wall. These methods can reduce wall adhesion to some extent, but cannot eliminate it completely. Active cleaning methods mainly rely on manual tower shutdown for cleaning or simple mechanical wall scrapers. Manual cleaning is inefficient and dangerous, while common fixed or rotating wall scrapers, although capable of continuous or intermittent cleaning, have a fixed cleaning force. Especially for granulation towers tens of meters high, the scrapers are prone to bending deformation due to excessive overhang, resulting in insufficient rigidity and difficulty in maintaining a constant contact pressure with the inner wall of the tower. This makes them effective for initial soft scale, but often ineffective against the hardened, plateaued layer formed after long-term operation, easily leading to jamming or damage. In addition, the wall scraping components are exposed to the high temperature, high humidity, and highly corrosive environment inside the tower for a long time, resulting in a short lifespan and frequent maintenance.

[0004] Based on this, the development of an automatic descaling system for urea granulation towers that can intelligently identify scaling conditions, adaptively adjust cleaning intensity, efficiently remove stubborn scale layers, and possess good environmental tolerance and operational reliability is a clear and urgent technical requirement for promoting the continuous, intelligent, and efficient development of urea production. Summary of the Invention

[0005] The purpose of this invention is to provide a urea granulation tower that can intelligently identify the scaling state, adaptively adjust the cleaning intensity, and efficiently remove stubborn scale layers, so as to solve the technical problems and shortcomings of existing urea granulation towers in terms of tower wall adhesion and difficulty in effective cleaning.

[0006] This invention is achieved through the following technical solution: An anti-sticking urea granulation tower with a descaling device includes a cylindrical tower body. A top filter unit is provided at the upper end of the tower body, and an automatic descaling device is provided below the top filter unit. The automatic descaling device includes a rotating carrier cylinder rotatably disposed at the lower end of the top filter unit and concentrically disposed with the tower body. A connecting plate extending radially outward is provided on the rotating carrier cylinder. A vertically downward sliding rod is fixed on the connecting plate. A counterweight shovel block is slidably disposed at the upper limit of the vertical sliding rod, and the bottom of the counterweight shovel block has a thin blade that fits against the inner wall of the tower body. The connecting plate is connected to the lower end of the rotating carrier cylinder by a sealing box. The sealing box is equipped with a tower wall information acquisition module for detecting the scaling inside the tower body. The tower wall information acquisition module is electrically connected to the control system of the anti-sticking urea granulation tower. The sealing box or rotating carrier cylinder is equipped with a lifting mechanism for lifting the counterweight shovel block by a traction rope.

[0007] As a further feature of the above scheme, the lower surface of the top filter unit is provided with a concentric downward extending ring, and the outer circular surface of the extending ring is provided with an annular slide rail and an annular roller groove. The upper inner side of the rotating carrier cylinder is provided with an annular groove that cooperates with the annular slide rail, and a plurality of rollers that interact with the annular roller groove.

[0008] As a further feature of the above scheme, a gear ring is concentrically fixed in the rotating carrier cylinder, a rotary motor is fixedly installed on the top filter unit, and a drive gear that meshes with the gear ring is provided on the motor shaft of the rotary motor.

[0009] As a further feature of the above scheme, the lifting mechanism includes a winding motor, a winding wheel driven by the winding motor, and two guide wheels set in a sealed box. The traction rope passes around the two guide wheels in sequence, and its two ends are connected to the winding wheel and the counterweight shovel block, respectively.

[0010] As a further provision of the above scheme, the automatic descaling device also includes an impact lifting mechanism. The impact lifting mechanism includes a pull rod that is vertically and movably installed in a sealed box. The top of the pull rod is connected to a pull rope wheel that is suspended on a traction rope between two guide wheels. A rotating shaft is rotatably installed in the sealed box next to the pull rod. One end of the rotating shaft is connected to a rotary drive device, and a notched gear is provided on the rotating shaft. The side end of the pull rod is provided with a meshing tooth groove that meshes with the notched gear.

[0011] As a further feature of the above scheme, a distance sensor for monitoring the height position of the counterweight shovel is provided at the bottom of the sealed box located directly above the counterweight shovel, and the distance sensor is electrically connected to the control system.

[0012] As a further provision of the above scheme, the inner wall of the tower body is enclosed by stainless steel plates, and the counterweight shovel is made of stainless steel with a weight between 10 and 30 kg.

[0013] As a further feature of the above solution, the tower wall information acquisition module is either an industrial camera or a laser scanner.

[0014] As a further feature of the above scheme, a bearing is provided at the bottom center of the rotating carrier cylinder, and a urea nozzle is rotatably mounted in the bearing. The upper end of the urea nozzle is connected to the urea supply system through a liquid delivery tube.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The urea granulation tower disclosed in this invention achieves fully automated descaling from detection and judgment to execution, eliminating the need for manual entry into the high-risk tower interior and completely eliminating the safety risks of manual descaling. Simultaneously, the online descaling capability supports maintenance without interrupting production, effectively ensuring the long-term, continuous, and stable operation of the urea granulation unit.

[0016] The automatic descaling device disclosed in this invention uses a vertical slide bar set on a rotating carrier cylinder as a guide to drive a counterweight shovel block to slide down along a fixed trajectory to clean the scale. This design transforms the traditional "long cantilever" wall scraping structure into a "vertical guide" motion, fundamentally overcoming the problem of flexural deformation caused by the excessive longitudinal dimension of the wall scraper. It ensures that the shovel block can maintain a stable and tight fit with the inner wall of the tower during a journey of tens of meters, effectively removing scale from the entire height range of the tower.

[0017] The automatic descaling device disclosed in this invention not only relies on the weight of the counterweight scraper for conventional scraping, but also integrates a unique impact lifting mechanism. When encountering stubborn, hard-to-remove deposits, the system can automatically sense and control the scraper to first lift it and then release it instantly, generating tremendous impact kinetic energy under the acceleration of gravity, thus powerfully breaking up the hard scale. This combination of "gravity scraping" and "kinetic energy impact" significantly improves the adaptability to scale of varying hardness and the thoroughness of cleaning.

[0018] This invention also uses a tower wall information acquisition module to scan and detect the tower wall. Combined with the analysis of the control system, it realizes online monitoring and precise positioning of scaling. The scaling removal operation is triggered by the system's intelligent judgment and can focus on cleaning severely scaled areas. This changes the traditional equipment's extensive mode of blindly scraping throughout the process and improves the accuracy and energy efficiency of the scaling removal operation.

[0019] This invention integrates the core components of the tower wall information acquisition module, traction rope transmission components, and impact lifting mechanism into a sealed enclosure, isolating them from the harsh environment of high temperature, high humidity, and strong corrosion inside the tower. This design significantly reduces the failure rate of critical components and improves the operational reliability and service life of the entire automatic descaling device under demanding conditions. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the 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.

[0021] Figure 1 This is a schematic diagram of the external three-dimensional structure of the anti-sticking urea granulation tower in this invention; Figure 2 This is a schematic diagram of the internal three-dimensional structure of the anti-sticking urea granulation tower in this invention; Figure 3 This is a three-dimensional structural diagram of the automatic descaling device and the top filter unit assembled in this invention; Figure 4 This is a three-dimensional structural diagram of the rotating carrier cylinder and other components mounted on it in this invention; Figure 5 This is a schematic diagram of the internal planar structure of the rotating carrier cylinder and the sealed box in this invention; Figure 6 This is a schematic diagram of the three-dimensional structure of the sealing box, counterweight shovel, and pull rod in this invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The following will refer to the appendix... Figures 1-6 This application will be described in detail with reference to the embodiments. Example 1

[0024] like Figure 1 and Figure 2As shown, this embodiment 1 discloses an anti-sticking urea granulation tower with a descaling device. Its main structure includes a tower body 1, a top filter unit 2, a bottom air supply unit 3, and a control system for controlling the entire granulation tower (not shown in the figure).

[0025] The tower body 1 is a vertically arranged cylindrical shape, with its inner wall made of stainless steel plate. A material collection hopper 11 is provided at the bottom, and a corresponding unloading mechanism is provided in the material collection hopper 11. The specific unloading mechanism is existing technology and is not shown in detail. The top filter unit 2 and the bottom air supply unit 3 are also conventional settings, and will not be described in detail in this embodiment 1.

[0026] The key design feature of this embodiment 1 is that an automatic descaling device 4 is installed below the top filter unit 2. The automatic descaling device 4 consists of two parts: a tower wall information acquisition module and a scraper block descaling module. During the long-term operation of the granulation tower, the tower wall information acquisition module can rotate 360° from top to bottom to collect the scale on the tower wall. After the control system judges the data, it drives the scraper block descaling module to perform the subsequent cleaning procedure.

[0027] like Figures 3 to 6 As shown, the automatic descaling device 4 includes a rotating carrier cylinder 41 located directly below the top filter unit 2 and inside the tower body 1. A lower extension ring 21, concentrically arranged with the rotating carrier cylinder 41, is provided on the lower surface of the top filter unit 2. An annular slide rail 211 and an annular roller groove 212 are provided on the outer circumference of the lower extension ring 21. The inner side of the outer circumference of the rotating carrier cylinder 41 is provided with an annular groove 411 that mates with the annular slide rail 211, and multiple evenly arranged rollers 412 that interact with the annular roller groove 212. A gear ring 413 is concentrically welded and fixed to the bottom wall of the rotating carrier cylinder 41. A rotary motor 42 is installed in the top filter unit 2. The lower end of the motor shaft of the rotary motor 42 is equipped with a drive gear 421 that meshes with the gear ring 413. Under the power input of the rotary motor 42 and the combined action of the annular slide rail 211 and the annular roller groove 212, the rotating carrier cylinder 41 can rotate stably around the central axis of the tower body 1 below the top filter unit 2. At the same time, a bearing 414 that runs vertically through the bottom center of the rotating carrier cylinder 41 is also provided. A urea nozzle 5 is rotatably installed in the bearing 414. The upper end of the urea nozzle 5 is connected to the urea supply system through a liquid delivery pipe 51.

[0028] A radially outwardly extending connecting plate 43 is provided at the lower end of the outer circular surface of the rotating carrier cylinder 41. One or two vertical sliding rods 44 are provided on the connecting plate 43, extending vertically downward to the lower end of the tower body 1. A counterweight shovel block 45 is slidably mounted on the upper limit of the vertical sliding rod 44, and a lifting mechanism 46 is provided on the rotating carrier cylinder 41 for lifting or lowering the counterweight shovel block 45. In specific design, the counterweight shovel block 45 is made of stainless steel, with a thin blade at the bottom, and is tightly fitted to the inner wall of the tower body 1 under the restriction of the vertical sliding rod 44. At the same time, the weight of the counterweight shovel block 45 is set between 10 and 30 kg, so that it has a good scraping effect on the scale adhering to the inner wall of the tower body 1 during the lowering process.

[0029] A sealed box 47 is provided between the lower surface of the rotating carrier cylinder 41 and the connecting plate 43. A tower wall information acquisition module 48 is installed in the sealed box 47, which extends obliquely from its bottom and faces the side wall of the tower body 1. The tower wall information acquisition module 48 can be an industrial camera, laser scanner, etc. The scaling condition on the side wall of the tower body at the current position can be obtained through the tower wall information acquisition module 48.

[0030] The lifting mechanism 46 includes a winding wheel 461 disposed inside the sealed box 47 or the rotating drum 41. In this figure, the winding wheel 461 is disposed inside the rotating drum 41, and a winding motor 462 with a self-locking function is connected to the winding wheel 461. At the same time, two guide wheels 463 are disposed on the lower surface of the rotating drum 41 inside the sealed box 47. A traction rope 464 is wound around the winding wheel 461. After the traction rope 464 extends into the sealed box 47, it is guided by the two guide wheels 463 and then extends downward out of the sealed box 47 and is connected to the counterweight shovel block 45.

[0031] In the operation of the anti-sticking urea granulation tower disclosed in Embodiment 1, the rotating carrier cylinder 41 is driven by the rotating motor 42 to slowly rotate around the central axis of the tower body 1 at regular intervals. During the rotation, the tower wall information acquisition module 48 detects the scaling on the inner wall of the tower body. When serious scaling is found on the inner wall of the tower body 1, the control system will first temporarily stop the rotation of the rotating carrier cylinder 41, and then perform the scaling removal action.

[0032] When the descaling command is issued, the take-up motor 462 starts to rotate, thereby unwinding the traction rope 464 wound on the take-up reel 461. Then, the counterweight scraper 45 connected to the traction rope 464 moves downward along the vertical slide bar 44 under its own weight. As the counterweight scraper 45 moves downward, under its own weight, and with its thin blade at the bottom adhering to the inner wall of the tower body 1, it can remove the scale adhering to the inner wall of the tower body 1. After the counterweight scraper 45 moves to the bottom of the vertical slide bar 44, the take-up motor 462 is controlled to rotate in the opposite direction, thereby winding the traction rope 464 through the take-up reel 461. Then, the counterweight scraper 45 moves along the vertical slide bar 44 to the top and resets. Example 2

[0033] Example 2 discloses a method based on the technical solution in Example 1, which further optimizes and upgrades its ability to remove scale. The similarities between Example 2 and Example 1 will not be described again.

[0034] like Figure 5 and Figure 6 As shown, in this embodiment 2, a vertically penetrating pull rod 471 is provided at the bottom of the sealed box 47. A pull rope wheel 472 located between two guide wheels 463 is connected to the top of the pull rod 471, and the pull rope wheel 472 is suspended on the traction rope 464 between the two guide wheels 463. A rotating shaft 473 is provided in the sealed box 47 located on one side of the pull rod 471. One end of the rotating shaft 473 is connected to a rotary drive device 474. A notched gear 475 opposite to the pull rod 471 is provided on the rotating shaft 473, and a meshing tooth groove that meshes with the notched gear 475 is opened on the side end of the pull rod 471.

[0035] In addition, in this embodiment 2, a distance sensor 49 is provided on the bottom wall of the sealed box 47 directly above the counterweight shovel block 45. Specifically, the distance sensor 49 is a laser rangefinder, which is electrically connected to the control system of the entire granulation tower.

[0036] In this embodiment 2, through the above-described further optimized and improved design, when the lifting mechanism 46 lowers the counterweight shovel block 45 to remove scale from the inner wall of the tower, if some severely hardened and highly adhesive scale is encountered, it is difficult to remove it by the weight of the counterweight shovel block 45 alone. Since the winding motor 462 continues to unwind, but the distance sensor 49 detects that the horizontal height of the counterweight shovel block 45 remains unchanged, it can be determined that there is scale that is difficult to remove. At this time, the rotary drive device 474 is activated to make the notched gear 475 rotate one revolution. Then, under the meshing transmission between the notched gear 475 and the meshing groove on the pull rod 471, the pull rod 471 will move downward, and pull the traction rope 464 between the two guide wheels 463 downward through the pull rope wheel 472, thereby raising the counterweight shovel block 45 to a certain height. Subsequently, when the notched gear 475 disengages from the meshing groove on the pull rod 471, the counterweight shovel block 45 will fall rapidly under its own weight and generate a certain amount of kinetic energy. At this time, combined with the weight of the counterweight shovel block 45 itself, it can clean up these hard-to-remove dirt blocks.

[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A urea granulation tower with a descaling device for preventing wall adhesion, comprising a cylindrical tower body, wherein a top filter unit is provided at the upper end of the tower body, characterized in that, An automatic descaling device is provided below the top filter unit. The automatic descaling device includes a rotating carrier cylinder that is rotatably disposed at the lower end of the top filter unit and concentrically disposed with the tower body. A connecting plate extending radially outward is provided on the rotating carrier cylinder. A vertically downward sliding rod is fixed on the connecting plate. A counterweight shovel block is slidably disposed at the upper limit of the vertical sliding rod, and the bottom of the counterweight shovel block has a thin blade that fits against the inner wall of the tower body. The connecting plate is connected to the lower end of the rotating carrier cylinder by a sealing box. The sealing box is equipped with a tower wall information acquisition module for detecting the scaling inside the tower body. The tower wall information acquisition module is electrically connected to the control system of the anti-sticking urea granulation tower. The sealing box or rotating carrier cylinder is equipped with a lifting mechanism for lifting the counterweight shovel block by a traction rope.

2. The anti-sticking urea granulation tower with a descaling device according to claim 1, characterized in that, The lower surface of the top filter unit is provided with a concentric downward extending ring. The outer circular surface of the extending ring is provided with an annular slide rail and an annular roller groove. The upper inner side of the rotating carrier cylinder is provided with an annular groove that cooperates with the annular slide rail and a plurality of rollers that interact with the annular roller groove.

3. The anti-sticking urea granulation tower with a descaling device according to claim 2, characterized in that, A gear ring is concentrically fixed in the rotating carrier cylinder, and a rotary motor is fixedly installed on the top filter unit. The motor shaft of the rotary motor is provided with a drive gear that meshes with the gear ring.

4. The anti-sticking urea granulation tower with a descaling device according to claim 1, characterized in that, The lifting mechanism includes a winding motor, a winding wheel driven by the winding motor, and two guide wheels set in a sealed box. The traction rope passes around the two guide wheels in sequence, and its two ends are connected to the winding wheel and the counterweight shovel block, respectively.

5. A urea granulation tower with a descaling device according to claim 4, characterized in that, The automatic descaling device also includes an impact lifting mechanism, which includes a pull rod vertically and movably installed in a sealed box. The top of the pull rod is connected to a pull rope wheel suspended on a traction rope between two guide wheels. A rotating shaft is rotatably installed in the sealed box next to the pull rod. One end of the rotating shaft is connected to a rotary drive device, and a notched gear is provided on the rotating shaft. The side end of the pull rod is provided with a meshing tooth groove that meshes with the notched gear.

6. A urea granulation tower with a descaling device according to claim 5, characterized in that, A distance sensor for monitoring the height of the counterweight shovel is installed at the bottom of the sealed box located directly above the counterweight shovel, and the distance sensor is electrically connected to the control system.

7. A urea granulation tower with a descaling device according to claim 1, characterized in that, The inner wall of the tower is enclosed by stainless steel plates, and the counterweight shovel is made of stainless steel with a weight between 10 and 30 kg.

8. The anti-sticking urea granulation tower with a descaling device according to claim 1, characterized in that, The tower wall information acquisition module is either an industrial camera or a laser scanner.

9. A urea granulation tower with a descaling device according to claim 1, characterized in that, A bearing is provided at the bottom center of the rotating carrier cylinder, and a urea nozzle is rotatably mounted in the bearing. The upper end of the urea nozzle is connected to the urea supply system through a liquid delivery tube.

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