Fluidized bed granulation system and method
By forming small-grain fertilizer seed crystals in the granulation section of the fluidized bed granulation system and spraying them into large-grain fertilizers, the problem of low roundness of large-grain fertilizers in the traditional fluidized bed granulation system is solved, and an efficient and low-cost fertilizer granulation process is achieved.
Patent Information
- Application Number
- CN202510161483.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-13
- Publication Date
- 2025-06-06
AI Technical Summary
In the prior art, large-grain fertilizers made of fluidized beds are not round.
A fluidized bed granulation system is designed, including a granulation section and a cooling section. Small-grained fertilizer seed crystals are formed in the granulation section through seed-making nozzles and granulation nozzles, and converted into large-grained fertilizer by spraying the fertilizer melt.
It has achieved the production of large-grain fertilizers with good roundness and high hardness, simplified the process flow, and reduced the equipment and installation and operation costs.
Smart Images
Figure CN120094488A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of fertilizer processing, and in particular to a fluidized bed granulation system and method. Background Art
[0002] Fertilizer, as one of the main indispensable factors for plant growth, has multiple functions and effects in agricultural production. The main form of fertilizer in agricultural production is granular fertilizer, which is divided into small particles (particle size less than 2mm) and large particles (particle size between 2 and 4mm). Since small granular fertilizer sticks to plant leaves and causes "seedling burn", the demand for large granular fertilizer is higher under the market mechanism. In the processing and production of granular fertilizer, the commonly used large granular fertilizer granulation production is carried out through a fluidized bed.
[0003] Fluidized bed granulation is also called boiling granulation or one-step granulation. It is to put the materials into a closed container at one time, mix the materials evenly in the container, and flow them in the container to form particles. In the traditional fluidized bed granulation production process, in the granulation stage, it is necessary to use a crusher to break the materials into small particles, and use the small particles produced by the crusher as seeds for further spraying and granulation to produce large particle products. Since the small particles produced by the crusher are irregular in shape and poor in roundness, the large particle products finally formed have low roundness. Summary of the invention
[0004] The invention provides a fluidized bed granulation system and method, which are used to solve the defect of low roundness of large granular fertilizers manufactured by using a fluidized bed in the prior art.
[0005] The present invention provides a fluidized bed granulation system, comprising a fluidized bed granulation device, wherein the fluidized bed granulation device comprises a fluidized bed granulator and a fluidized bed cooler, wherein the fluidized bed granulator and the fluidized bed cooler respectively form a granulation section and a cooling section in the fluidized bed granulation device; the granulation section is used to produce small-particle fertilizer seeds and convert the small-particle fertilizer seeds into large-particle fertilizer, and the cooling section is connected to the granulation section to receive and cool the granular fertilizer converted by the granulation section.
[0006] The granulation section is provided with a seed crystal nozzle and a granulation nozzle, the seed crystal nozzle and the granulation nozzle are connected to a fertilizer melt source through a pipeline, the fertilizer melt source sprays the fertilizer melt to the granulation section through the seed crystal nozzle to form small-particle fertilizer seeds in the granulation section, and the fertilizer melt source sprays the fertilizer melt on the surface of the small-particle fertilizer seeds through the granulation nozzle to convert into large-particle fertilizer.
[0007] According to a fluidized bed granulation system provided by the present invention, the granulation section includes a seeding area and a granulation area which sequentially form an assembly line operation, the seeding area is provided with the seeding nozzle, the fertilizer molten liquid source sprays the fertilizer molten liquid to the seeding area through the seeding nozzle to form small-particle fertilizer seeds in the seeding area; the granulation area is provided with the granulation nozzle, the fertilizer molten liquid source sprays the fertilizer molten liquid to the granulation area through the granulation nozzle to spray and transform the small-particle fertilizer seeds transported to the granulation area into large-particle fertilizer.
[0008] According to a fluidized bed granulation system provided by the present invention, the outlet of the cooling section is connected with a material dividing screen, and the material dividing screen is used to screen the granular fertilizer output from the cooling section.
[0009] The material dividing screen comprises a small particle discharge port and a large particle discharge port, the small particle discharge port is connected to the granulation section through a pipeline, and the large particle discharge port outputs a granular fertilizer product.
[0010] According to a fluidized bed granulation system provided by the present invention, a bucket elevator is arranged on the pipeline connecting the small particle discharge port and the granulation section.
[0011] The large particle discharge port is connected to a product cooler so as to output the granular fertilizer product through the product cooler output port.
[0012] According to a fluidized bed granulation system provided by the present invention, the fertilizer molten liquid source is a liquid tank containing fertilizer molten liquid, the liquid tank is connected to a delivery pump through a pipeline, and the delivery pump is connected to the granulation section through a pipeline.
[0013] According to a fluidized bed granulation system provided by the present invention, the fertilizer melt in the liquid tank is at least one of urea melt, ammonium nitrate melt, calcium ammonium nitrate melt, and compound fertilizer melt, and the weight percentage of the fertilizer melt ranges from 92% to 99.7wt%.
[0014] According to a fluidized bed granulation system provided by the present invention, the fluidized bed granulation system also includes an atomizing fan, the atomizing fan is connected to an atomizing air preheater through a pipeline, and the atomizing air preheater is connected to the fluidized bed granulation equipment through a pipeline.
[0015] The fluidized bed granulation system further comprises a fluidizing fan, the fluidizing fan is connected to a fluidizing air preheater via a pipeline, and the fluidizing air preheater is connected to the fluidized bed granulation equipment via a pipeline.
[0016] According to a fluidized bed granulation system provided by the present invention, the tail gas outlet of the fluidized bed granulation equipment is connected to a dust collector, and the dust collector is connected to an induced draft fan, so that the tail gas of the fluidized bed granulation equipment is discharged through the dust collector and the induced draft fan.
[0017] The present invention further provides a fluidized bed granulation method, which is applicable to any one of the fluidized bed granulation systems described above, and the fluidized bed granulation method comprises: A fertilizer melt is sprayed into a granulation section in a fluidized bed granulation device based on a fertilizer melt source, and small-granular fertilizer seeds are formed in a seeding area of the granulation section.
[0018] The formed small-particle fertilizer seed crystals flow to the granulation area of the granulation section, and the fertilizer melt is sprayed on the small-particle fertilizer seed crystals based on the fertilizer melt source, so as to transform the small-particle fertilizer seed crystals into large-particle fertilizer.
[0019] The fluidized bed cooler is used to cool the formed large granular fertilizer in the cooling section of the fluidized bed granulation equipment and output the granular fertilizer.
[0020] A fluidized bed granulation method according to the present invention further comprises: The granular fertilizer output from the cooling section is screened by the classifying screen, the small granular fertilizer screened by the classifying screen is transported to the granulation section, and the large granular fertilizer screened by the classifying screen is output as a granular fertilizer product.
[0021] The atomizing air is outputted into the fluidized bed granulation device by an atomizing fan and an atomizing air preheater, so as to form uniform droplets of the fertilizer melt sprayed in the fluidized bed granulation device.
[0022] The fluidizing air is outputted into the fluidized bed granulation equipment by a fluidizing fan and a fluidizing air preheater, so as to keep the granular fertilizer in the fluidized bed granulation equipment in a fluidized suspension state.
[0023] The fluidized bed granulation system and method provided by the present invention first form small-particle fertilizer seeds through fertilizer melt, and then further form large-particle fertilizer. No adhesive is used to bond the raw materials, and granular fertilizer is directly generated. There is no need to use a crusher to crush the product, and large-particle fertilizer with good roundness and high hardness can be directly produced, which simplifies the process flow and reduces the equipment and installation and operation costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] 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.
[0025] Figure 1 It is a schematic diagram of the flow of the fluidized bed granulation system provided by the present invention.
[0026] Figure numerals: 1. fluidized bed granulation equipment; 101. granulation section; 111. seeding area; 121. granulation area; 102. cooling section; 2. material dividing screen; 3. bucket elevator; 4. product cooler; 5. conveying pump; 6. atomizing fan; 7. atomizing air preheater; 8. fluidizing fan; 9. fluidizing air preheater; 10. dust collector; 11. induced draft fan. DETAILED DESCRIPTION
[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] Combine the following Figure 1 The specific composition of the fluidized bed granulation system and the specific process of the fluidized bed granulation method of the present invention are described.
[0033] One embodiment of the present invention provides a fluidized bed granulation system, see Figure 1 As shown, the fluidized bed granulation system includes a fluidized bed granulation device 1, and the fluidized bed granulation device 1 includes a fluidized bed granulator and a fluidized bed cooler. The fluidized bed granulator and the fluidized bed cooler form a granulation section 101 and a cooling section 102 in the fluidized bed granulation device 1 respectively; the granulation section 101 is used to produce small-granular fertilizer seeds and convert the small-granular fertilizer seeds into large-granular fertilizers, and the cooling section 102 is connected to the granulation section 101 to receive and cool the granular fertilizers converted by the granulation section 101.
[0034] The granulation section 101 is provided with a seeding nozzle and a granulation nozzle. The seeding nozzle and the granulation nozzle are connected to a fertilizer melt source through a pipeline. The fertilizer melt source sprays the fertilizer melt to the granulation section 101 through the seeding nozzle to form small-particle fertilizer seeds in the granulation section 101. The fertilizer melt source sprays the fertilizer melt on the surface of the small-particle fertilizer seeds through the granulation nozzle to convert them into large-particle fertilizer.
[0035] It can be understood that the fluidized bed granulation system of the present embodiment forms the liquid supply, granulation and cooling process of granular fertilizer granulation through the fluidized bed granulation equipment 1 and the external fertilizer molten liquid source, wherein the fluidized bed granulation equipment 1 includes two main parts, namely the fluidized bed granulator (granulation section 101) and the fluidized bed cooler (cooling section 102), the granulation section 101 and the cooling section 102 are physically connected and sequentially connected in the process flow to complete the granule manufacturing and cooling process. The granulation section 101 is provided with a seeding nozzle and a granulation nozzle, which are connected to an external fertilizer melt source through a pipeline. The fertilizer melt is provided by an external source and transported to the seeding nozzle and the granulation nozzle through a pipeline. In the granulation section 101, the seeding nozzle atomizes the fertilizer melt into fine droplets, which solidify in the granulation section 101 to form small-particle fertilizer seeds, and then continue to spray on the small-particle fertilizer seeds through the granulation nozzle. As more fertilizer melt is sprayed on the small-particle fertilizer seeds, it gradually grows into larger particles. The formed larger-particle fertilizer enters the cooling section 102, where it is cooled to a suitable temperature to prevent product quality degradation or other problems caused by high temperature. The hot large-particle fertilizer is cooled in the cooling section 102 and is ready for further processing or direct packaging and shipment.
[0036] It should be understood that the fluidized bed granulation system of this embodiment first forms small-particle fertilizer seeds through the fertilizer melt, and then further forms large-particle fertilizer. This embodiment directly generates granular fertilizer in the granulation section 101 through the seed making nozzle and the granulation nozzle, without the need to produce small-particle seeds through a crusher. Since the small-particle fertilizer seeds used in this embodiment are self-generated and have good roundness, large-particle fertilizers with good roundness and high hardness can be directly produced, which simplifies the process and reduces the equipment and installation and operation costs.
[0037] In some embodiments of the fluidized bed granulation system of the present invention, see Figure 1 As shown, the granulation section 101 includes a seeding area 111 and a granulation area 121 which sequentially form an assembly line operation. The seeding area 111 is provided with a seeding nozzle, and a fertilizer molten liquid source sprays the fertilizer molten liquid to the seeding area 111 through the seeding nozzle to form small-particle fertilizer seeds in the seeding area 111; the granulation area 121 is provided with a granulation nozzle, and a fertilizer molten liquid source sprays the fertilizer molten liquid to the granulation area 121 through the granulation nozzle to spray and transform the small-particle fertilizer seeds transported to the granulation area 121 into large-particle fertilizer.
[0038] The fluidized bed granulation system of this embodiment further subdivides the granulation section 101 into two specialized functional areas: a seeding area 111 and a granulation area 121. The two areas are arranged in sequence in an assembly line manner to jointly complete the conversion process from the molten liquid to the finished large-particle fertilizer.
[0039] In the seeding area 111, the process of generating small-particle fertilizer seed crystals is mainly completed. The molten liquid from the fertilizer molten liquid source is sprayed out in the form of mist through the seeding nozzle arranged in this area, and is quickly cooled and solidified in the air to form initial small-particle fertilizer seed crystals.
[0040] In the granulation area 121, the small-particle fertilizer seed crystals produced in the seed crystal area 111 are mainly converted into large-particle fertilizer. When the small-particle fertilizer seed crystals are transported to the granulation area 121, the granulation nozzles in this area continue to spray the fertilizer melt on the surface of the small-particle fertilizer seed crystals. As more layers of melt accumulate and solidify, the small-particle fertilizer seed crystals gradually grow into the required large-particle fertilizer. In this process, precise control of the spraying amount and conditions (such as temperature, air flow speed, etc.) of the melt can ensure the growth rate and final quality of the particles.
[0041] Since the seeding region 111 and the granulation region 121 are arranged in the form of an assembly line, the entire process can achieve continuous production, improve efficiency, and help maintain consistency in product quality. This embodiment achieves a more efficient particle manufacturing process by introducing a division of labor between the seeding region 111 and the granulation region 121, while ensuring high quality standards of the product.
[0042] In some other embodiments of the fluidized bed granulation system of the present invention, see again Figure 1 As shown, the outlet of the cooling section 102 is connected to a dividing screen 2, which is used to screen the granular fertilizer output from the cooling section 102. The dividing screen 2 includes a small particle outlet and a large particle outlet, the small particle outlet is connected to the granulation section 101 through a pipeline, and the large particle outlet outputs the granular fertilizer product.
[0043] In order to ensure that the particle size of the final product meets the standard and effectively recycle the particles that do not meet the standard to optimize resource utilization, the fluidized bed granulation system of this embodiment introduces a classifying screen 2. The classifying screen 2 is connected to the outlet of the cooling section 102 and is responsible for screening the granular fertilizer after the cooling treatment. The classifying screen 2 can distinguish between small granular fertilizers that do not reach the predetermined size and large granular fertilizers that meet the requirements.
[0044] The small-particle fertilizers screened out by the material-separating screen 2 are transported back to the granulation section 101 through a specific pipeline, and these small-particle fertilizers can be further grown into qualified large-particle fertilizers in the granulation section 101, thereby avoiding material waste and improving overall production efficiency. The large-particle fertilizers that meet the preset specifications screened out by the material-separating screen 2 are directly output as finished products through the large-particle discharge port, ready to enter the market or the next stage of processing.
[0045] This embodiment can ensure that all granular fertilizers output as final products meet specific size requirements through effective screening by the material dividing screen 2, which helps to improve the consistency of product quality. The small granular fertilizers that do not meet the size requirements are reintroduced into the granulation process, which not only reduces the generation of waste, but also maximizes the utilization of resources and reduces production costs. It is understandable that according to the changes in actual production and market demand, the proportion of granular fertilizers of different sizes can be flexibly controlled by adjusting the working parameters of the material dividing screen 2, thereby adjusting the production capacity.
[0046] Furthermore, by designing the screening levels and screening ports of the material screen 2, some oversized fertilizer particles (such as fertilizer particles with a particle size greater than 4 mm) can be screened out. The screened oversized fertilizer particles can be connected to a dissolving device through a pipeline for dissolution, and then connected to a fertilizer melt source through a pipeline as a fertilizer melt for reproduction.
[0047] A bucket elevator 3 is provided on the pipeline connecting the small particle discharge port and the granulation section 101. The bucket elevator 3 vertically lifts the small particle fertilizer screened by the material separation screen 2 and transports it to the granulation section 101. This design solves the space limitation problem that may be encountered in horizontal transportation and ensures that the small particle fertilizer can be smoothly returned to the starting stage of the granulation process. The bucket elevator 3 can realize continuous material transportation, ensure the smooth operation of the entire system, and improve production efficiency. Since the bucket elevator 3 has good material handling performance, it can effectively prevent pipeline blockage and maintain the stability and reliability of the system.
[0048] The large particle discharge port is connected to a product cooler 4 to output the granular fertilizer product through the output port of the product cooler 4. The product cooler 4 provides an additional cooling environment for the large granular fertilizer that has been initially cooled, ensuring that they reach a suitable storage and transportation temperature, and avoiding quality degradation or safety hazards caused by excessive temperature. The granular fertilizer treated by the product cooler 4 can be directly output as a finished product, ready to enter the market or be packaged, etc. This step helps to improve the appearance quality and physical properties of the product, such as hardness and roundness.
[0049] In some embodiments of the fluidized bed granulation system of the present invention, the fertilizer molten liquid source is a liquid tank containing fertilizer molten liquid, the liquid tank is connected to the delivery pump 5 through a pipeline, and the delivery pump 5 is connected to the granulation section 101 through a pipeline. The fertilizer molten liquid in the liquid tank is at least one of urea molten liquid, ammonium nitrate molten liquid, calcium ammonium nitrate molten liquid, and compound fertilizer molten liquid, and the weight percentage of the fertilizer molten liquid ranges from 92% to 99.7wt%.
[0050] It can be understood that in the fluidized bed granulation system of the present invention, the fertilizer molten liquid source can specifically be one or more liquid tanks containing fertilizer molten liquid, these liquid tanks are connected to the delivery pump 5 through pipelines, and then the delivery pump 5 is connected to the seeding nozzle and the granulation nozzle in the granulation section 101 through another set of pipelines, ensuring that the molten liquid can be stably and continuously delivered to the seeding area 111 and the granulation area 121 to support an efficient particle formation process.
[0051] The weight percentage (wt%) of the fertilizer melt in the liquid tank is controlled between 92% and 99.7wt%. This high concentration range helps to ensure that the melt has appropriate physical properties (such as viscosity and fluidity), which is conducive to the formation of high-quality granular fertilizers, and can reduce moisture content and reduce drying energy consumption. The fertilizer melt can be urea melt, ammonium nitrate melt, calcium ammonium nitrate melt or compound fertilizer melt prepared as needed. According to the selection of fertilizer melts, fertilizer products such as large-granular urea, large-granular ammonium nitrate, large-granular calcium ammonium nitrate, and large-granular compound fertilizer can be produced.
[0052] In some specific examples of the fluidized bed granulation system of the present invention, the fluidized bed granulation system also includes an atomizing fan 6, which is connected to an atomizing air preheater 7 through a pipeline, and the atomizing air preheater 7 is connected to the fluidized bed granulation device 1 through a pipeline. The atomizing fan 6 can provide the required airflow pressure to break the fertilizer molten liquid into fine droplets, thereby promoting particle formation. The atomizing air preheater 7 is used to heat the atomizing air from the atomizing fan 6 to ensure that it reaches an appropriate temperature so that it can better contact with the fertilizer molten liquid, help form uniform small particle seeds, and accelerate the drying process. Specifically, the airflow generated by the atomizing fan 6 is transported to the atomizing air preheater 7 through a pipeline, where it is preheated and then enters the granulation section 101 of the fluidized bed granulation device 1 through a pipeline. The preheated atomizing air acts on the fertilizer molten liquid in the granulation section 101 to break it into fine droplets, and also helps to control the temperature of the granulation environment to prevent the particles from sticking due to excessive temperature.
[0053] The fluidized bed granulation system also includes a fluidizing fan 8, which is connected to a fluidizing air preheater 9 through a pipeline, and the fluidizing air preheater 9 is connected to the fluidized bed granulation equipment 1 through a pipeline. The fluidizing fan 8 can provide sufficient airflow to support the particles and make them in a suspended state, that is, the so-called "fluidization", to facilitate mass transfer and heat transfer. The fluidizing air preheater 9 preheats the fluidizing air from the fluidizing fan 8 and adjusts it to a temperature suitable for the granulation process to ensure that the particles can grow under optimal conditions. Specifically, the airflow provided by the fluidizing fan 8 is also connected to the fluidizing air preheater 9 through a pipeline, and after preheating, it is sent to the granulation section 101 and the cooling section 102 of the fluidized bed granulation equipment 1 through another set of pipelines. In the granulation section 101, the preheated fluidizing air helps to maintain the fluidized state of the material and ensure the uniform distribution and growth of the particles, while in the cooling section 102, it is mainly used to take away heat and help large-particle fertilizers cool down.
[0054] In some examples of the fluidized bed granulation system of the present invention, the exhaust gas outlet of the fluidized bed granulation equipment 1 is connected to the dust collector 10, and the dust collector 10 is connected to the induced draft fan 11 to discharge the exhaust gas of the fluidized bed granulation equipment 1 through the dust collector 10 and the induced draft fan 11.
[0055] It is understandable that in order to ensure environmental protection and operational safety during the production process, this example specially designs an exhaust gas treatment system, which consists of a dust collector 10 and an induced draft fan 11, and is used to treat the exhaust gas discharged from the fluidized bed granulation equipment 1. Specifically, during the fluidized bed granulation process, due to the heating and evaporation of the material, exhaust gas containing dust and other pollutants will be generated. These exhaust gases are first discharged from the exhaust gas outlet of the fluidized bed granulation equipment 1, and then directly enter the dust collector 10 through the pipeline. In the dust collector 10, the exhaust gas is subjected to efficient dust removal treatment, and most of the dust and particulate matter are effectively captured, reducing the impact on the environment. According to the specific application scenario, the dust collector can adopt different types of equipment, such as bag dust collectors, electrostatic dust collectors or wet scrubbers. The exhaust gas purified by the dust collector 10 is safely discharged to the atmosphere through the pipeline system under the action of the induced draft fan 11. The suction force provided by the induced draft fan 11 ensures the smooth flow of exhaust gas in the whole treatment process. At the same time, the induced draft fan 11 is an optional equipment. The air volume can also be adjusted according to actual needs. It is selected whether the induced draft fan 11 is needed to ensure the best treatment effect.
[0056] On the other hand, the present invention also provides a fluidized bed granulation method. The fluidized bed granulation method of the present invention can correspond to the fluidized bed granulation system in any of the above embodiments. In some specific embodiments, the fluidized bed granulation method of the present invention includes: spraying the fertilizer melt to the granulation section 101 in the fluidized bed granulation equipment 1 based on the fertilizer melt source, forming small-particle fertilizer seeds in the seeding area 111 of the granulation section 101; forming small-particle fertilizer seeds flowing to the granulation area 121 of the granulation section 101, spraying the small-particle fertilizer seeds with fertilizer melt based on the fertilizer melt source, and converting the small-particle fertilizer seeds into large-particle fertilizer. Using a fluidized bed cooler, the formed large-particle fertilizer is cooled in the cooling section 102 in the fluidized bed granulation equipment 1 and the granular fertilizer is output.
[0057] The fluidized bed granulation method also includes: based on the sieving of the granular fertilizer output from the cooling section 102 by the sieving screen 2, the small granular fertilizer sieving by the sieving screen 2 is transported to the granulation section 101, and the large granular fertilizer sieving by the sieving screen 2 is output as a granular fertilizer product (a small amount of oversized particles sieving out can enter the dissolving device for dissolution and participate in the reproduction as a fertilizer molten liquid). The atomizing fan 6 and the atomizing air preheater 7 are used to output atomizing air into the fluidized bed granulation device 1 to form uniform droplets of the fertilizer molten liquid sprayed in the fluidized bed granulation device 1. The fluidizing fan 8 and the fluidizing air preheater 9 are used to output fluidizing air into the fluidized bed granulation device 1 to keep the granular fertilizer in the fluidized bed granulation device 1 in a fluidized suspension state.
[0058] It can be understood that the fluidized bed granulation method of this embodiment is intended to provide a granulation method that can produce large-particle fertilizers with good roundness and high hardness without the need for a crusher. Specifically, the fluidized bed granulation method of this embodiment includes a seed formation stage, a particle growth stage, and a cooling and output stage.
[0059] Seed formation stage: Based on the fertilizer molten liquid source (such as urea, ammonium nitrate, calcium ammonium nitrate or compound fertilizer molten liquid), the delivery pump 5 is connected through a pipeline, and then the fertilizer molten liquid is sprayed from the seeding nozzle to the granulation section 101 in the fluidized bed granulation equipment 1. In the seeding area 111 of the granulation section 101, the preheated atomizing wind provided by the atomizing fan 6 breaks the molten liquid into fine droplets, which are quickly cooled and solidified in the air to form initial small-particle fertilizer seed crystals.
[0060] Particle growth stage: The small-particle fertilizer seeds formed in the seed formation stage are then transported to the granulation area 121 of the granulation section 101. In the granulation area 121, the molten liquid from the fertilizer molten liquid source is sprayed onto the surface of the seeds again through the granulation nozzle. As more layers of molten liquid accumulate and solidify, the seeds gradually grow into large-particle fertilizers that meet the requirements.
[0061] Cooling and output stage: The formed larger granular fertilizer enters the cooling section 102 in the fluidized bed granulation equipment 1. In the cooling section 102, the preheated fluidized air provided by the fluidizing fan 8 helps maintain the fluidized state of the material and takes away the heat to cool the large granular fertilizer. The large granular fertilizer after cooling is screened by the material separator 2. The qualified large granular fertilizer is further cooled by the product cooler 4 and finally output from the output port as a finished product. The smaller granular fertilizer that does not meet the standard can be sent back to the granulation section 101 through the bucket elevator 3, realizing the recycling of materials.
[0062] 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 system, characterized in that: The invention comprises a fluidized bed granulation device (1), wherein the fluidized bed granulation device (1) comprises a fluidized bed granulator and a fluidized bed cooler, wherein the fluidized bed granulator and the fluidized bed cooler respectively form a granulation section (101) and a cooling section (102) in the fluidized bed granulation device (1); the granulation section (101) is used to produce small-granular fertilizer seed crystals and convert the small-granular fertilizer seed crystals into large-granular fertilizer; the cooling section (102) is connected to the granulation section (101) to receive and cool the granular fertilizer converted by the granulation section (101); The granulation section (101) is provided with a seed crystal nozzle and a granulation nozzle. The seed crystal nozzle and the granulation nozzle are connected to a fertilizer melt source via a pipeline. The fertilizer melt source sprays the fertilizer melt onto the granulation section (101) via the seed crystal nozzle to form small-particle fertilizer seeds in the granulation section (101). The fertilizer melt source sprays the fertilizer melt on the surface of the small-particle fertilizer seeds via the granulation nozzle to convert the fertilizer into large-particle fertilizer.
2. The fluidized bed granulation system according to claim 1, characterized in that: The granulation section (101) comprises a seeding area (111) and a granulation area (121) which sequentially form an assembly line operation. The seeding area (111) is provided with the seeding nozzle, and the fertilizer molten liquid source sprays the fertilizer molten liquid to the seeding area (111) through the seeding nozzle, so as to form small-particle fertilizer seeds in the seeding area (111); the granulation area (121) is provided with the granulation nozzle, and the fertilizer molten liquid source sprays the fertilizer molten liquid to the granulation area (121) through the granulation nozzle, so as to spray and transform the small-particle fertilizer seeds transported to the granulation area (121) into large-particle fertilizer.
3. The fluidized bed granulation system according to claim 2, characterized in that: The outlet of the cooling section (102) is connected to a material separation screen (2), and the material separation screen (2) is used to separate the granular fertilizer output from the cooling section (102); The material dividing screen (2) comprises a small particle discharge port and a large particle discharge port, the small particle discharge port is connected to the granulation section (101) via a pipeline, and the large particle discharge port outputs a granular fertilizer product.
4. The fluidized bed granulation system according to claim 3, characterized in that: A bucket elevator (3) is provided on the pipeline connecting the small particle discharge port and the granulation section (101); and / or, The large particle discharge port is connected to a product cooler (4) so as to discharge the granular fertilizer product through the output port of the product cooler (4).
5. The fluidized bed granulation system according to claim 1, characterized in that: The fertilizer molten liquid source is a liquid tank containing fertilizer molten liquid, the liquid tank is connected to a delivery pump (5) via a pipeline, and the delivery pump (5) is connected to the granulation section (101) via a pipeline.
6. The fluidized bed granulation system according to claim 5, characterized in that: The fertilizer melt in the liquid tank is at least one of urea melt, ammonium nitrate melt, calcium ammonium nitrate melt, and compound fertilizer melt, and the weight percentage of the fertilizer melt is in the range of 92% to 99.7wt%.
7. The fluidized bed granulation system according to any one of claims 1 to 6, characterized in that: The fluidized bed granulation system further comprises an atomizing fan (6), wherein the atomizing fan (6) is connected to an atomizing air preheater (7) via a pipeline, and the atomizing air preheater (7) is connected to the fluidized bed granulation equipment (1) via a pipeline; and / or, The fluidized bed granulation system further comprises a fluidizing fan (8), wherein the fluidizing fan (8) is connected to a fluidizing air preheater (9) via a pipeline, and the fluidizing air preheater (9) is connected to the fluidized bed granulation equipment (1) via a pipeline.
8. The fluidized bed granulation system according to any one of claims 1 to 6, characterized in that: The tail gas outlet of the fluidized bed granulation equipment (1) is connected to a dust collector (10), and the dust collector (10) is connected to an induced draft fan (11), so that the tail gas of the fluidized bed granulation equipment (1) is discharged externally through the dust collector (10) and the induced draft fan (11).
9. A fluidized bed granulation method, characterized in that: The fluidized bed granulation system according to any one of claims 1 to 8, wherein the fluidized bed granulation method comprises: Based on a fertilizer molten liquid source, a fertilizer molten liquid is sprayed onto a granulation section (101) in a fluidized bed granulation device (1), so as to form small-particle fertilizer seed crystals in a seed crystal forming area (111) of the granulation section (101); The small-particle fertilizer seed crystals are formed and flow to the granulation area (121) of the granulation section (101), and the fertilizer melt is sprayed on the small-particle fertilizer seed crystals based on the fertilizer melt source to transform the small-particle fertilizer seed crystals into large-particle fertilizer; The fluidized bed cooler is used to cool the formed large granular fertilizer in the cooling section (102) in the fluidized bed granulation equipment (1) and output the granular fertilizer.
10. The fluidized bed granulation method according to claim 9, characterized in that: Also includes: Based on the sieving of the granular fertilizer outputted from the cooling section (102) by the sieving screen (2), the small granular fertilizer sieving by the sieving screen (2) is conveyed to the granulation section (101), and the large granular fertilizer sieving by the sieving screen (2) is outputted as a granular fertilizer product; Outputting atomizing air into the fluidized bed granulation device (1) using an atomizing fan (6) and an atomizing air preheater (7) to form uniform droplets of the fertilizer melt sprayed in the fluidized bed granulation device (1); A fluidizing fan (8) and a fluidizing air preheater (9) are used to output fluidizing air into the fluidized bed granulation equipment (1) so as to keep the granulated fertilizer in the fluidized bed granulation equipment (1) in a fluidized suspension state.