Fluidized bed granulation device and granulation method thereof

Abstract

The invention relates to the technical field of fertilizer processing, and provides a fluidized bed granulation device and a granulation method.The fluidized bed granulation device comprises a fluidized bed granulator, a cooler, a molten liquid conveying pump and a seed crystal making machine, and the molten liquid conveying pump is communicated with the fluidized bed granulator and the cooler through a first flow path; the molten liquid conveying pump is used for pumping molten liquid to the fluidized bed granulator and the cooler through the first flow path; the seed crystal making machine is respectively communicated with the fluidized bed granulator, the cooler and the molten liquid delivery pump through a second flow path, and is used for making the molten liquid pumped by the molten liquid delivery pump through the second flow path into seed crystals; and the seed crystal is conveyed to the fluidized bed granulator and the cooler through the second flow path. According to the invention, large-particle products with good roundness and good hardness can be produced without crushing of a crusher, and the product quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizer processing, and in particular to a fluidized bed granulating device and a granulating method thereof. Background Art

[0002] Fertilizer, as one of the main factors indispensable for plant growth, has many functions and effects in agricultural production. The application of nitrogen fertilizer can promote the growth of crop branches and leaves, increase leaf area, thereby improving photosynthesis efficiency and increasing yield. Granular fertilizer can reduce the hygroscopicity of fertilizer, reduce pollution to the environment, and is also easy to apply.

[0003] There are many common granulation production methods and equipment. The fertilizer preparation process, from simple fertilizer blending to extrusion granulation, disc granulation, drum granulation, spray granulation, high tower granulation, fluidized bed granulation, etc., all play an indispensable role.

[0004] Fluidized bed granulation is an important granulation production device. The large urea particles produced by fluidized bed granulation have high strength. However, due to the need for crushing during production, the roundness of the seed crystal is not good enough, so the roundness of the product is not good enough. Summary of the invention

[0005] The invention provides a fluidized bed granulation device and a granulation method thereof, which are used to solve the defect in the prior art that the roundness of fluidized bed granulation seeds is not good, resulting in low roundness of products, and achieve the production of large granule products with good roundness and hardness without crushing by a crusher, thereby improving product quality.

[0006] The present invention provides a fluidized bed granulation device, comprising: Fluidized bed granulator and cooler; a molten liquid delivery pump, the molten liquid delivery pump being in communication with the fluidized bed granulator and the cooler via a first flow path, the molten liquid delivery pump being used to pump molten liquid to the fluidized bed granulator and the cooler via the first flow path; A seed crystal making machine, which is connected to the fluidized bed granulator and the cooler and the molten liquid delivery pump through a second flow path, respectively. The seed crystal making machine is used to make seeds from the molten liquid pumped by the molten liquid delivery pump through the second flow path, and the seeds are delivered to the fluidized bed granulator and the cooler through the second flow path.

[0007] According to a fluidized bed granulation device provided by the present invention, the fluidized bed granulation device also includes an atomization flow path, the atomization flow path is respectively connected to the crystal seed making machine, the fluidized bed granulator and the cooler, an atomization fan and an atomization wind preheater are provided on the atomization flow path, the atomization fan is used to pressurize the atomization wind, and the atomization wind preheater is used to heat the pressurized atomization wind.

[0008] According to a fluidized bed granulation device provided by the present invention, the fluidized bed granulation device also includes a fluidizing flow path, which is respectively connected to the crystal seed making machine, the fluidized bed granulator and the cooler, and a fluidizing fan and a fluidizing air preheater are provided on the fluidizing flow path, the fluidizing fan is used to pressurize the fluidizing air, and the fluidizing air preheater is used to heat the pressurized fluidizing air.

[0009] According to a fluidized bed granulation device provided by the present invention, a seed granulation nozzle is arranged in the seed granulation machine, and the seed granulation nozzle is a non-standard customized granulation nozzle.

[0010] According to a fluidized bed granulation device provided by the present invention, the fluidized bed granulator and cooler includes a granulation area and a cooling area, the granulation area is arranged at the feed end of the fluidized bed granulator and cooler, and the cooling area is arranged at the discharge end of the fluidized bed granulator and cooler.

[0011] According to a fluidized bed granulation device provided by the present invention, the fluidized bed granulation device also includes a safety screen, which is arranged at the discharge end of the fluidized bed granulator and cooler, and is used to screen the products produced by the fluidized bed granulator and cooler.

[0012] According to a fluidized bed granulation device provided by the present invention, the fluidized bed granulation device also includes an output flow path, which is connected to the rear end of the safety screen, and the output flow path is used to circulate qualified products after screening by the safety screen. A product cooler is provided on the output flow path, and the product cooler is used to cool the qualified products on the output flow path.

[0013] Alternatively, the fluidized bed granulation device also includes a recovery flow path, which is connected between the rear end of the safety screen and the feed end of the fluidized bed granulator and cooler, and a bucket elevator is provided on the recovery flow path, and the bucket elevator is used to transport unqualified products to the feed end of the fluidized bed granulator and cooler as seeds.

[0014] According to a fluidized bed granulation device provided by the present invention, the fluidized bed granulation device further comprises a dust removal device, the dust removal device is respectively connected to the crystal seed making machine and the fluidized bed granulator and cooler, and the dust removal device is used to remove dust from the gas discharged from the crystal seed making machine or the fluidized bed granulator and cooler; Alternatively, the fluidized bed granulation device further comprises an induced draft fan, which is connected to the dust removal device and is used to drive the gas in the dust removal device to be discharged.

[0015] According to a fluidized bed granulation device provided by the present invention, the molten liquid comprises any one of 92wt%~99.7wt% urea molten liquid, calcium ammonium nitrate molten liquid, ammonium nitrate molten liquid, calcium nitrate molten liquid or compound fertilizer molten liquid.

[0016] On the other hand, the present invention also provides a granulation method, which is applied to the fluidized bed granulation device as described above, comprising the following steps: The molten liquid delivery pump pressurizes the molten liquid and divides it into two paths, one path enters the seed making machine, and the other path directly enters the fluidized bed granulator and cooler; In the seed crystal making machine, the molten liquid is sprayed into fine droplets, which are rapidly cooled and solidified under the action of atomizing and fluidizing winds to form initial small particle seed crystals. Small particle seed crystals enter the fluidized bed granulator and cooler through the feed port. The fluidized bed granulator and cooler coat the seed crystals with molten liquid under the action of atomizing wind and fluidizing wind to make them grow; The granulated products are screened through a safety screen, and qualified products are cooled in a product cooler before being output, while particles that do not meet the standards are collected by a bucket elevator as crystal seeds and re-entered into the fluidized bed granulator and cooler for further processing.

[0017] The fluidized bed granulation device provided by the present invention is that the molten liquid is directly pumped to the fluidized bed granulator and the cooler by the molten liquid delivery pump, and a small part of the molten liquid is sent to the seed making machine through the second flow path to make seed crystals. These seeds are then reintroduced into the fluidized bed granulator and the cooler, where they serve as cores and gradually grow into large particles by spraying more molten liquid. Since this process avoids the need for physical crushing of the finished particles, it is possible to produce large particle products without a crusher. Since the particles grow layer by layer in the fluidized bed by spraying, rather than by mechanical crushing, the shape of the final product is closer to a sphere. The airflow in the fluidized bed can act evenly on each growing particle to ensure that they can grow relatively consistently in all directions. In the fluidized bed granulation process, as each layer of molten liquid cools and solidifies, it will be tightly combined with the next layer to form a particle with a more compact overall structure. Compared with particles that have been crushed and then re-bonded, naturally formed particles have a more uniform internal stress distribution, reducing the possibility of microcracks and other defects, thereby increasing the overall strength and hardness of the particles to improve product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a connection schematic diagram of an embodiment of a fluidized bed granulation device provided by the present invention.

[0020] Figure 2 It is a connection schematic diagram of another embodiment of the fluidized bed granulation device provided by the present invention.

[0021] Figure 3 It is a connection schematic diagram of another embodiment of the fluidized bed granulation device provided by the present invention.

[0022] Figure 4 It is a connection schematic diagram of another embodiment of the fluidized bed granulation device provided by the present invention.

[0023] Reference numerals: 1. Fluidized bed granulation device; 10. Fluidized bed granulator and cooler; 11. Molten liquid delivery pump; 12. Seeding machine; 13. Atomizing fan; 14. Atomizing air preheater; 15. Fluidizing fan; 16. Fluidizing air preheater; 17. Dust removal device; 18. Induced draft fan; 19. Safety screen; 20. Product cooler; 21. Bucket elevator. DETAILED DESCRIPTION

[0024] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0025] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0026] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0027] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0028] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0029] Combine the following Figures 1 to 4 , the fluidized bed granulation device provided by the embodiment of the present invention is described in detail through specific embodiments and application scenarios.

[0030] In the embodiment of the present invention, Figure 1-Figure 4 As shown, the fluidized bed granulation device 1 includes a fluidized bed granulator and cooler 10, a molten liquid delivery pump 11 and a seed crystal making machine 12. The molten liquid delivery pump 11 is connected to the fluidized bed granulator and cooler 10 through a first flow path, and the molten liquid delivery pump 11 is used to pump molten liquid to the fluidized bed granulator and cooler 10 through the first flow path; the seed crystal making machine 12 is connected to the fluidized bed granulator and cooler 10 and the molten liquid delivery pump 11 through a second flow path, respectively, and the seed crystal making machine 12 is used to make crystal seeds from the molten liquid pumped by the molten liquid delivery pump 11 through the second flow path, and the crystal seeds are transported to the fluidized bed granulator and cooler 10 through the second flow path.

[0031] The fluidized bed granulator and cooler 10 is a core granulation device, and the fluidized bed granulator and cooler 10 provides a controlled environment in which the molten liquid grows layer by layer on the surface of the seed crystal by spraying to form particles. The gas flow in the fluidized bed keeps the particles in a suspended state, ensuring uniform heating and cooling, thereby promoting uniform growth of the particles and helping to form a product with good roundness. Among them, the fluidized bed granulator and cooler 10 can be a single device, or it can be divided into two devices, a fluidized bed granulator and a fluidized bed cooler, according to production capacity or actual installation needs.

[0032] The molten liquid delivery pump 11 is responsible for pumping the molten liquid from the storage or preparation area to the fluidized bed granulator and cooler 10 and the seed crystal making machine 12. It distributes the molten liquid through two different first flow paths and second flow paths to meet the needs of different stages.

[0033] The molten liquid delivery pump 11 pumps most of the molten liquid directly to the fluidized bed granulator and cooler 10 through the first flow path for spraying and granulating on the existing seed crystals.

[0034] The molten liquid delivery pump 11 pumps a small portion of the molten liquid to the seed making machine 12 through the second flow path for making initial small particle seed crystals.

[0035] The seed crystal making machine 12 is specially used to generate small particle seeds, which are then introduced into the fluidized bed granulator and cooler 10 as the basis for granulation. The seed crystal making machine 12 receives a small amount of molten liquid from the molten liquid delivery pump 11 and converts it into small particles suitable for use as granulation cores through specific process conditions (such as temperature, pressure, etc.).

[0036] The first flow path is the main passage between the molten liquid delivery pump 11 and the fluidized bed granulator and cooler 10, and is used to transfer most of the molten liquid. This flow path ensures that sufficient molten liquid can be continuously supplied to the fluidized bed granulator and cooler 10 to maintain a stable granulation process.

[0037] The second flow path is a dedicated channel between the molten liquid delivery pump 11 and the crystal seed making machine 12, and also connects the crystal seed making machine 12 and the fluidized bed granulator and cooler 10. Its main functions include guiding a portion of the molten liquid to the crystal seed making machine 12 to make crystal seeds; and then reintroducing the crystal seeds made by the crystal seed making machine 12 into the fluidized bed granulator and cooler 10 as the core of the new granulation process.

[0038] The molten liquid delivery pump 11 draws the molten liquid from the source and divides it into two parts as needed. Most of it directly enters the fluidized bed granulator and cooler 10 through the first flow path, while a small part is sent to the seed crystal making machine 12 through the second flow path.

[0039] The seed crystal generator 12 generates small particle seeds using the received molten liquid, and the seeds are then transported back to the fluidized bed granulator and cooler 10 through a second flow path.

[0040] In the fluidized bed granulator and cooler 10, the seed crystals act as cores and gradually grow into large particles by spraying more molten liquid. The airflow in the fluidized bed ensures uniform distribution and growth of the particles.

[0041] After screening, qualified products are cooled and output as finished products, while unqualified small particles can be returned to the system as new seeds to continue participating in the granulation process.

[0042] The molten liquid of the present application is directly pumped to the fluidized bed granulator and cooler 10 by the molten liquid delivery pump 11, and a small part of the molten liquid is sent to the seed making machine 12 to make seeds through the second flow path. These seeds are then reintroduced into the fluidized bed granulator and cooler 10, where they serve as cores and gradually grow into large particles by spraying more molten liquid. Since this process avoids the need for physical crushing of the finished particles, it is possible to produce large particle products without a crusher. Since the particles grow layer by layer in the fluidized bed by spraying, rather than by mechanical crushing, the shape of the final product is closer to a sphere. The airflow in the fluidized bed can act evenly on each growing particle to ensure that they can obtain relatively consistent growth in all directions. In the fluidized bed granulation process, as each layer of molten liquid cools and solidifies, it will be tightly combined with the next layer to form a particle with a more compact overall structure. Compared with particles that have been crushed and then re-bonded, naturally formed particles have a more uniform internal stress distribution, reducing the possibility of microcracks and other defects, thereby increasing the overall strength and hardness of the particles to improve product quality.

[0043] Reference Figures 1 to 4 According to a fluidized bed granulation device 1 provided by the present invention, the fluidized bed granulation device 1 also includes an atomization flow path, which is respectively connected to a seed making machine 12, a fluidized bed granulator and a cooler 10, and an atomization fan 13 and an atomization wind preheater 14 are provided on the atomization flow path. The atomization fan 13 is used to pressurize the atomization wind, and the atomization wind preheater 14 is used to heat the pressurized atomization wind.

[0044] It can be understood that the atomization flow path is a pipeline system connecting the seed making machine 12 and the fluidized bed granulator and cooler 10. Its purpose is to ensure that the atomization air can smoothly reach the seed making machine 12 and the fluidized bed granulator and cooler 10 to provide the necessary atomization medium for the seed making or granulation process.

[0045] The atomizing fan 13 is located on the atomizing flow path, and its main function is to pressurize the air (or other inert gas) entering the fluidized bed. The pressurized air (i.e., atomizing air) has higher kinetic energy and penetrating power, and can more effectively penetrate the molten droplets and disperse them into finer droplets. This fine atomization effect helps the molten liquid to be more evenly distributed in the seed crystal making machine 12, the fluidized bed granulator and the cooler 10, thereby promoting the uniform growth of the particles.

[0046] The atomizing air preheater 14 is also located on the atomizing flow path, immediately following the atomizing fan 13. Its main function is to heat the pressurized atomizing air to increase its temperature. The heated atomizing air not only has higher energy, which can more effectively promote the atomization and dispersion of the molten liquid, but also provides additional heat during the cooling and solidification of the molten droplets. This heating effect helps to reduce the internal stress of the particles caused by temperature differences, thereby improving the overall strength and hardness of the particles. In addition, the preheated atomizing air also helps to maintain a stable temperature in the fluidized bed, providing a good environment for the continuous growth of particles.

[0047] Reference Figures 1 to 4 According to a fluidized bed granulation device 1 provided by the present invention, the fluidized bed granulation device 1 also includes a fluidizing flow path, which is respectively connected to a seed making machine 12, a fluidized bed granulator and a cooler 10, and a fluidizing fan 15 and a fluidizing air preheater 16 are provided on the fluidizing flow path. The fluidizing fan 15 is used to pressurize the fluidizing air, and the fluidizing air preheater 16 is used to heat the pressurized fluidizing air.

[0048] It is understood that the fluidized flow path is a key passage connecting the seed crystal making machine 12 and the fluidized bed granulator and cooler 10, and is responsible for conveying the specially treated fluidized air to the two devices. The fluidized air can keep the particles in the bed in a suspended state, achieve good mixing and heat and mass transfer, and promote the interaction between the particles and the gas, thereby accelerating the granulation process.

[0049] The fluidizing fan 15 is located on the fluidizing flow path, and its main function is to pressurize the air (or other inert gas) entering the fluidized bed. The pressurized air (i.e., fluidizing air) has higher kinetic energy and penetrating power, and can more effectively penetrate the particles in the bed layer, so that the particles remain in a suspended state. This suspended state helps to uniformly mix and collide between particles, thereby promoting the growth and uniformity of the particles. In addition, the pressurized fluidizing air can also improve the fluidization efficiency of the bed layer, making the granulation process more stable and efficient.

[0050] The fluidizing air preheater 16 is also located on the fluidizing flow path, immediately following the fluidizing fan 15. Its main function is to heat the pressurized fluidizing air to increase its temperature. The heated fluidizing air has higher energy and can more effectively promote the heat and mass transfer process in the bed. This heating effect helps to maintain the temperature stability in the bed and provide a suitable environment for the growth of particles. In addition, the preheated fluidizing air can also reduce the temperature difference in the bed, avoid the particles from generating internal stress due to temperature differences, and thus improve the overall quality and strength of the particles.

[0051] In one embodiment, the flow rate of the molten liquid flowing through the seed making machine 12 is smaller than the flow rate of the molten liquid flowing through the fluidized bed granulator and the cooler 10 during the same period of time.

[0052] It can be understood that a smaller flow rate helps to more accurately control the distribution and cooling rate of the melt in the seed making machine 12, thereby forming uniform and high-quality seeds. A lower flow rate allows the melt to stay in the seed making machine 12 for a longer time, increasing the time window for seed formation, and is conducive to the generation of larger and denser seeds, which can serve as core particles in the subsequent granulation process to promote the formation of larger particles.

[0053] A larger flow rate entering the fluidized bed granulator and cooler 10 can ensure sufficient airflow and material flow, maintain a stable fluidized state in the fluidized bed, avoid the occurrence of local accumulation or dead zones, and thus improve the efficiency of the entire granulation process. After a higher flow rate of molten liquid enters the fluidized bed granulator and cooler 10, it can be quickly deposited and solidified on the formed seed crystals, accelerate the growth process of the particles, and improve the number and quality of particles generated per unit time.

[0054] Reference Figures 1 to 4 According to a fluidized bed granulation device 1 provided by the present invention, the fluidized bed granulator and cooler 10 includes a granulation area and a cooling area. The granulation area is arranged at the feed end of the fluidized bed granulator and cooler 10, and the cooling area is arranged at the discharge end of the fluidized bed granulator and cooler 10.

[0055] It can be understood that the fluidized bed granulator and cooler 10 is divided into a granulation area and a cooling area, which realizes a clear functional division. The granulation area is mainly responsible for converting the input molten liquid or seed crystals into preliminarily formed particles, while the cooling area is responsible for cooling and solidifying these particles to ensure that the particles have a stable shape and performance when leaving the device. This partition design helps to optimize the operating conditions of each module, thereby improving the overall production efficiency.

[0056] The granulation area is located at the feeding end, which can ensure that the input materials are granulated at the appropriate temperature and pressure. This helps to control the growth rate and shape of the particles, so that the particles have good uniformity and stability at the initial stage of formation. The cooling area is located at the discharging end, which can quickly cool and solidify the formed particles to prevent the particles from deformation or cracking due to temperature fluctuations after leaving the equipment.

[0057] Reference Figures 1 to 4 According to a fluidized bed granulation device 1 provided by the present invention, the fluidized bed granulation device 1 also includes a safety screen 19, which is arranged at the discharge end of the fluidized bed granulator and cooler 10, and the safety screen 19 is used to screen the products produced by the fluidized bed granulator and cooler 10.

[0058] It is understood that the main function of the safety screen 19 is to control the particle size of the granulated product to ensure that all particles leaving the granulator meet the predetermined particle size standard. Through screening, particles that are too large or too small can be removed to ensure the uniformity and consistency of the final product. Through the screening effect of the safety screen 19, particles of different sizes can be separated. This helps to further classify and process according to product requirements, such as sending particles of different sizes to different packaging lines or for subsequent processing. This flexibility can optimize the production process and improve production efficiency and flexibility.

[0059] Reference Figures 1 to 4 According to a fluidized bed granulation device 1 provided by the present invention, the fluidized bed granulation device 1 also includes an output flow path, the output flow path is connected to the rear end of the safety screen 19, the output flow path is used to circulate qualified products after screening by the safety screen 19, and a product cooler 20 is provided on the output flow path, and the product cooler 20 is used to cool the qualified products on the output flow path.

[0060] It is understandable that the output flow path serves as a bridge connecting the safety screen 19 and the subsequent processing equipment, and its main function is to ensure that the qualified products after screening can flow smoothly to the next process. Avoid the retention and accumulation of products in the production process, and improve production efficiency. At the same time, through the guidance of the output flow path, the products can be easily collected into a designated container or conveyor belt, ready for subsequent packaging, storage and other steps.

[0061] During the fluidized bed granulation process, the product often has a high temperature when it comes out of the granulator. If it is not cooled in time, the product may deform, stick or chemically change due to the high temperature, thereby affecting the product quality. Therefore, a product cooler 20 is provided on the output flow path to quickly cool the qualified products after screening, so that the temperature drops to a suitable range, ensuring the stability of the product's shape and performance. The cooling process also helps to further solidify the product and improve the hardness and wear resistance of the product.

[0062] Reference Figures 1 to 4 The fluidized bed granulation device 1 also includes a recovery flow path, which is connected between the rear end of the safety screen 19 and the feed end of the fluidized bed granulator and cooler 10. A bucket elevator 21 is provided on the recovery flow path. The bucket elevator 21 is used to transport unqualified products to the feed end of the fluidized bed granulator and cooler 10 as crystal seeds.

[0063] It is understandable that, in the present embodiment, the unqualified product is a particle whose particle size does not reach that of the qualified product. The recovery flow path serves as a key channel connecting the rear end of the safety screen 19 with the fluidized bed granulator and the feed end of the cooler 10, ensuring that the unqualified product can be reintroduced into the granulation process instead of being directly discarded. The material utilization rate is improved and waste is reduced. By re-sending the unqualified product into the granulator as a seed, the recovery flow path helps to maintain the continuity and stability of production and avoid affecting the normal production process due to the accumulation of unqualified products. The existence of the recovery flow path allows operators to promptly discover and handle unqualified products, thereby reducing the defective rate of the final product and improving the overall product quality.

[0064] Reference Figures 1 to 4 According to a fluidized bed granulation device 1 provided by the present invention, the fluidized bed granulation device 1 also includes a dust removal device 17, and the dust removal device 17 is connected to the seed making machine 12 and the fluidized bed granulator and cooler 10 respectively. The dust removal device 17 is used to remove dust from the gas discharged from the seed making machine 12 or the fluidized bed granulator and cooler 10.

[0065] It is understandable that during the operation of the seed crystal making machine 12 and the fluidized bed granulator and cooler 10, waste gas containing dust particles will be generated. If these waste gases are directly discharged into the atmosphere without treatment, they will pollute the environment and affect the air quality. The dust removal device 17 can effectively capture and remove dust particles in these waste gases, thereby reducing pollution to the environment and protecting the air quality.

[0066] In one embodiment, according to a fluidized bed granulation device 1 provided by the present invention, the fluidized bed granulation device 1 further includes an induced draft fan 18, the induced draft fan 18 is connected to the dust removal device 17, and the induced draft fan 18 is used to drive the gas in the dust removal device 17 to be discharged.

[0067] It is understood that the induced draft fan 18 generates negative pressure to draw the dust-containing gas generated by the seeding machine 12, the fluidized bed granulator and the cooler 10 into the dust removal device 17, which helps to ensure that all dust-containing gas can be effectively captured, thereby improving the dust removal efficiency.

[0068] Reference Figures 1 to 4According to a fluidized bed granulation device 1 provided by the present invention, the molten liquid includes any one of urea molten liquid, calcium ammonium nitrate molten liquid, ammonium nitrate molten liquid, calcium nitrate molten liquid or compound fertilizer molten liquid.

[0069] It is understandable that by selecting different types of melts or solutions as the components of the melt, different products can be obtained. The melt can be prepared as needed to improve the applicability of the device.

[0070] On the other hand, the present invention further provides a granulation method, which is applied to the fluidized bed granulation device 1 as described above, and comprises the following steps: The molten liquid delivery pump 11 pressurizes the molten liquid and divides it into two paths, one path enters the seed making machine 12, and the other path directly enters the fluidized bed granulator and cooler 10; In the seed crystal making machine 12, the molten liquid is sprayed into fine droplets, which are rapidly cooled and solidified under the action of atomizing wind and fluidizing wind to form initial small particle seed crystals; Small particle seed crystals enter the fluidized bed granulator and cooler 10 through the feed port, and the fluidized bed granulator and cooler 10 coats the seed crystals with molten liquid under the action of atomizing wind and fluidizing wind to make them grow; The granulated products are screened by a safety screen 19, and qualified products are cooled by a product cooler 20 before being output, while particles that do not meet the standards are collected by a bucket elevator 21 as crystal seeds and re-entered into the fluidized bed granulator and cooler 10 for further processing.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fluidized bed granulation device, characterized in that: include: Fluidized bed granulator and cooler; a molten liquid delivery pump, the molten liquid delivery pump being in communication with the fluidized bed granulator and the cooler via a first flow path, the molten liquid delivery pump being used to pump molten liquid to the fluidized bed granulator and the cooler via the first flow path; A seed crystal making machine, which is connected to the fluidized bed granulator and the cooler and the molten liquid delivery pump through a second flow path, respectively. The seed crystal making machine is used to make seeds from the molten liquid pumped by the molten liquid delivery pump through the second flow path, and the seeds are delivered to the fluidized bed granulator and the cooler through the second flow path.

2. The fluidized bed granulation device according to claim 1, characterized in that: The fluidized bed granulation device also includes an atomization flow path, which is respectively connected to the crystal seed making machine, the fluidized bed granulator and the cooler. An atomization fan and an atomization air preheater are provided on the atomization flow path. The atomization fan is used to pressurize the atomization air, and the atomization air preheater is used to heat the pressurized atomization air.

3. The fluidized bed granulation device according to claim 1, characterized in that: The fluidized bed granulation device also includes a fluidizing flow path, which is respectively connected to the crystal seed making machine, the fluidized bed granulator and the cooler. A fluidizing fan and a fluidizing air preheater are provided on the fluidizing flow path. The fluidizing fan is used to pressurize the fluidizing air, and the fluidizing air preheater is used to heat the pressurized fluidizing air.

4. The fluidized bed granulation device according to claim 1, characterized in that: A seeding granulation nozzle is arranged in the seeding machine, and the seeding granulation nozzle is a non-standard customized granulation nozzle.

5. The fluidized bed granulation device according to any one of claims 1 to 4, characterized in that: The fluidized bed granulator and cooler comprises a granulation area and a cooling area. The granulation area is arranged at the feed end of the fluidized bed granulator and cooler, and the cooling area is arranged at the discharge end of the fluidized bed granulator and cooler.

6. The fluidized bed granulation device according to claim 5, characterized in that: The fluidized bed granulation device further comprises a safety screen, which is arranged at the discharge end of the fluidized bed granulator and cooler, and is used to screen the products produced by the fluidized bed granulator and cooler.

7. The fluidized bed granulation device according to claim 6, characterized in that: The fluidized bed granulation device also includes an output flow path, which is connected to the rear end of the safety screen, and is used to circulate qualified products after screening by the safety screen. A product cooler is provided on the output flow path, and the product cooler is used to cool the qualified products on the output flow path. Alternatively, the fluidized bed granulation device also includes a recovery flow path, which is connected between the rear end of the safety screen and the feed end of the fluidized bed granulator and cooler, and a bucket elevator is provided on the recovery flow path, and the bucket elevator is used to transport unqualified products to the feed end of the fluidized bed granulator and cooler as seeds.

8. The fluidized bed granulation device according to any one of claims 1 to 4, characterized in that: The fluidized bed granulation device further comprises a dust removal device, which is respectively connected to the seed crystal making machine and the fluidized bed granulator and cooler, and is used to remove dust from the gas discharged from the seed crystal making machine or the fluidized bed granulator and cooler; Alternatively, the fluidized bed granulation device further comprises an induced draft fan, which is connected to the dust removal device and is used to drive the gas in the dust removal device to be discharged.

9. The fluidized bed granulation device according to any one of claims 1 to 4, characterized in that: The molten liquid includes any one of 92wt% to 99.7wt% urea molten liquid, calcium ammonium nitrate molten liquid, ammonium nitrate molten liquid, calcium nitrate molten liquid or compound fertilizer molten liquid.

10. A granulation method, applied to the fluidized bed granulation device according to any one of claims 1 to 9, characterized in that: The steps include: The molten liquid delivery pump pressurizes the molten liquid and divides it into two paths, one path enters the seed making machine, and the other path directly enters the fluidized bed granulator and cooler; In the seed crystal making machine, the molten liquid is sprayed into fine droplets, which are rapidly cooled and solidified under the action of atomizing and fluidizing winds to form initial small particle seed crystals. Small particle seed crystals enter the fluidized bed granulator and cooler through the feed port. The fluidized bed granulator and cooler coat the seed crystals with molten liquid under the action of atomizing wind and fluidizing wind to make them grow; The granulated products are screened through a safety screen, and qualified products are cooled in a product cooler before being output, while particles that do not meet the standards are collected by a bucket elevator as crystal seeds and re-entered into the fluidized bed granulator and cooler for further processing.

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