Fertilizer production equipment and methods

Abstract

This invention provides a fertilizer production equipment and method. The equipment includes: a fluidized bed granulator suitable for forming product granules; a granulation tower located upstream of the fluidized bed granulator; a fluidizing blower fluidly connected to the fluidized bed granulator; an atomizing blower fluidly connected to the fluidized bed granulator; a sieve located downstream of the fluidized bed granulator; and a product cooler connected to the sieve. The fertilizer production equipment and method provided by this invention can form high-quality large and medium-sized urea products or urea-based large-particle compound fertilizer products with uniform size and shape, good roundness, and high strength. It has good applicability; by simply changing the composition of the molten material, different fertilizer formulations can be easily produced, thereby meeting diverse market demands. It can be modified from existing tower granulation devices and processes, resulting in low investment costs.

Description

Technical Field

[0001] This invention relates to the field of fertilizer processing technology, and in particular to a fertilizer production equipment and method. Background Technology

[0002] There are various types of commonly used urea granulation production methods and equipment. Granulation technology is mainly divided into two categories: tower spray granulation and mechanical granulation; mechanical granulation can be further divided into fluidized bed granulation and rotary drum granulation.

[0003] However, tower spray granulation involves spraying urea through nozzles at the top of the granulation tower to form droplets, which then cool and crystallize through free settling. Because this process is short, and the crystallization of the molten urea proceeds from the outside in, it commonly results in low particle strength and small particle size. This problem is exacerbated in hot and humid seasons, as small particles easily adhere to plant leaves, causing "seedling burn" and affecting crop growth. Furthermore, many tower granulation units in China operate at full or overload (especially in summer), leading to reduced product quality and further exacerbating urea dust emissions.

[0004] Fertilizer granules produced by fluidized bed granulation are larger and stronger, but the roundness of the seed crystals is not good enough due to the need for crushing during production, which affects the quality of the product granules.

[0005] On the other hand, in recent years, intensive agriculture has demanded improved fertilizers capable of maximizing yields. A single vegetable variety may require a specific blend of various nutrients in terms of type and / or dosage. Therefore, there is a sustained and strong interest in developing highly flexible industrial processes to produce fertilizers with variable blends and / or concentrations of nutrients.

[0006] Therefore, there is an increasing need to develop fertilizer production equipment that produces fertilizer granules with good roundness, high strength, uniform quality, flexible particle size, and adaptability to various formulations. Summary of the Invention

[0007] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the present invention proposes a fertilizer production equipment and method.

[0008] The fertilizer production equipment provided by this invention includes:

[0009] Fluidized bed granulators are suitable for forming product granules;

[0010] A granulation tower is located upstream of the fluidized bed granulator;

[0011] A fluidizing blower is in fluid communication with the fluidized bed granulator;

[0012] The atomizing fan is in fluid communication with the fluidized bed granulator.

[0013] A sieve is located downstream of the fluidized bed granulator;

[0014] The product cooler is connected to the screener.

[0015] According to a fertilizer production device provided by the present invention, the fertilizer production device further includes a recycler;

[0016] The input end of the recoverer is connected to the screener, and the output end of the recoverer is connected to the fluidized bed granulator.

[0017] The fertilizer production equipment provided by the present invention further includes:

[0018] The feed pipe is connected to the fluidized bed granulator;

[0019] A liquid spraying device is installed at the connection between the feed pipe and the fluidized bed granulator. The liquid spraying device is suitable for atomizing the molten material for film atomization granulation.

[0020] The fertilizer production equipment provided by the present invention further includes:

[0021] A fluidizing air preheater is connected to the fluidizing blower, and the output end of the fluidizing air preheater is connected to the fluidized bed granulator.

[0022] According to a fertilizer production device provided by the present invention, a first heat exchanger is further provided between the fluidizing blower and the fluidizing air preheater, and the first heat exchanger is in fluid communication with the granulation tower.

[0023] The fertilizer production equipment provided by the present invention further includes:

[0024] An atomizing air preheater is connected to the atomizing fan, and the output end of the atomizing air preheater is connected to the fluidized bed granulator.

[0025] According to a fertilizer production device provided by the present invention, a second heat exchanger is further provided between the atomizing fan and the atomizing air preheater, and the second heat exchanger is in fluid communication with the granulation tower.

[0026] According to the fertilizer production equipment provided by the present invention, an exhaust gas purification device is further included, which is connected to the granulation tower and / or the fluidized bed granulator.

[0027] According to a fertilizer production equipment provided by the present invention, the exhaust gas purification device includes:

[0028] A washing machine, the input end of which is connected to the granulation tower and / or the fluidized bed granulator;

[0029] An exhaust fan is connected to the output end of the washing machine.

[0030] According to a fertilizer production device provided by the present invention, the fluidized bed granulator is connected to the screener through the discharge port, and the fluidized bed granulator includes a cooling device disposed at the discharge port.

[0031] The present invention also provides a fertilizer production method based on the fertilizer production equipment described in any one of the above claims, comprising:

[0032] The molten urea is granulated into particles through the granulation tower and then conveyed to the fluidized bed granulator as seed crystals.

[0033] The molten material is transported to the fluidized bed granulator through the feed pipe, fluidizing air is supplied to the fluidized bed granulator through the fluidizing blower, and atomizing air is supplied to the fluidized bed granulator through the atomizing blower;

[0034] The formed product particles are sieved using the sieve.

[0035] The qualified product particles screened out are cooled by the product cooler.

[0036] The unqualified product particles separated by the recycling device are transported back to the fluidized bed granulator.

[0037] The fertilizer production equipment and method provided by this invention, by setting the granulation tower upstream of the fluidized bed granulator, can transport the small particles with high roundness formed by the granulation tower to the fluidized bed granulator as seed crystals, thereby improving the roundness of the product particles; by setting the fluidized bed granulator, the molten material and urea seed crystals are fully mixed and stirred in the fluidized bed, so that the molten material can uniformly cover the surface of the seed crystals, forming high-quality large-particle urea products with uniform size and shape, good roundness, and high strength, or medium-particle and large-particle compound fertilizer products with urea as the main component.

[0038] On the other hand, the fertilizer production equipment and method provided by the present invention have good applicability. By simply changing the composition of the molten material entering the fluidized bed granulator, it is possible to easily produce fertilizers with different formulations, thereby meeting diverse market demands.

[0039] Furthermore, the fertilizer production equipment and method provided by the present invention can be modified based on existing tower granulation devices and processes, with low investment costs, and can improve the problem of existing granulation towers operating at full load or overload. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of the fertilizer production equipment provided in an embodiment of the present invention;

[0042] Figure 2 This is a schematic flowchart of the fertilizer production method provided in an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the fertilizer production equipment and method provided in the first aspect embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of the fertilizer production equipment and method provided in the second aspect embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of the fertilizer production equipment and method provided in the third aspect embodiment of the present invention;

[0046] Figure 6 This is a schematic diagram of the fertilizer production equipment and method provided in the fourth aspect embodiment of the present invention.

[0047] Figure label:

[0048] 100. Granulation tower; 200. Fluidized bed granulator; 201. Conveying pump; 212. Fluidizing blower; 213. Fluidizing air preheater; 222. Atomizing blower; 223. Atomizing air preheater; 231. Washer; 232. Exhaust fan; 241. First heat exchanger; 242. Second heat exchanger; 310. Screener; 320. Recovery unit; 400. Product cooler. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0050] The following is combined Figure 1 The fertilizer production equipment of the present invention is described.

[0051] like Figure 1As shown, the fertilizer production equipment provided in this embodiment of the invention includes a fluidized bed granulator 200, a granulation tower 100, a fluidizing blower 212, an atomizing blower 222, a sieve 310, and a product cooler 400. The fluidized bed granulator 200 is suitable for forming product granules; the granulation tower 100 is located upstream of the fluidized bed granulator 200; the fluidizing blower 212 is in fluid communication with the fluidized bed granulator 200; the atomizing blower 222 is in fluid communication with the fluidized bed granulator 200; the sieve 310 is located downstream of the fluidized bed granulator 200; and the product cooler 400 is connected to the sieve 310.

[0052] The fertilizer production equipment provided in this embodiment of the invention, by setting the granulation tower 100 upstream of the fluidized bed granulator 200, can transport the small particles with high roundness formed by the granulation tower 100 to the fluidized bed granulator 200 as seed crystals, thereby improving the roundness of the product particles; by setting the fluidized bed granulator 200, the molten material and urea seed crystals are fully mixed and stirred in the fluidized bed, so that the molten material can uniformly cover the surface of the seed crystals, forming high-quality large-particle urea products with uniform size and shape, good roundness, and high strength, or medium-particle and large-particle compound fertilizer products with urea as the main component.

[0053] On the other hand, the fertilizer production equipment provided in this embodiment of the invention has good applicability. By simply changing the composition of the molten material entering the fluidized bed granulator, it is possible to easily produce fertilizers with different formulations, thereby meeting diverse market demands.

[0054] Furthermore, the fertilizer production equipment provided in this embodiment of the invention can be modified based on existing tower granulation devices and processes, with low investment costs, and can improve the problem of existing granulation towers operating at full load or overload.

[0055] Specifically, see Figure 1 The granulation tower 100 is used to form solid small particles from molten urea, which serve as seed crystals for the fluidized bed granulator 200. Molten urea is fed into the top of the granulation tower 100 and sprayed down. As the molten urea descends from the top of the tower, it interacts with the gas resistance rising from the bottom of the tower, exchanges heat with it, and naturally cools and crystallizes, becoming well-rounded solid small particles when it falls to the bottom of the tower.

[0056] In this embodiment, the urea melt is 95%-99.7% by mass. The crystallization rate and particle size of urea can be adjusted by controlling parameters such as spray speed, temperature, and melt concentration. It is easy to understand that a device for introducing fluidizing air is correspondingly provided at the bottom of the granulation tower 100, and a device for pressurizing the urea melt can be correspondingly provided at the feeding point at the top of the tower; however, this embodiment does not limit this.

[0057] The granulation tower 100 is located upstream of the fluidized bed granulator 200. This means that the small urea particles formed in the granulation tower 100 are conveyed to the fluidized bed granulator 200 as seed crystals for the granulation process. This conveying can be achieved via belt drive or by adjusting the position; this embodiment does not limit the method. The seed crystal refers to already crystallized urea, which acts as a core and template, promoting the crystallization of the material and the growth of the particles during the granulation process.

[0058] The granulation tower 100 can directly adopt existing tower granulation equipment. The fertilizer production equipment provided by this invention is obtained by modifying existing tower granulation equipment, which can save costs and improve the problem of full-load and overload operation of existing tower granulation equipment.

[0059] The fluidized bed granulator 200 is a device used in the granulation process. It adopts fluidized bed technology, suspending materials in a gas flow. By adjusting the gas velocity and material characteristics, the materials are uniformly agitated and impacted by the gas within the fluidized bed, thereby achieving material bonding and shaping. It features high efficiency and uniformity.

[0060] In this embodiment, a fluidized bed granulator 200 is used to granulate seed crystals and molten material. The molten material comes into contact with the seed crystals from the granulation tower 100 and the air within the bed within the fluidized bed granulator 200, cooling and crystallizing around the seed crystals to form larger particles. The molten material can be urea molten material or compound fertilizer molten material; those skilled in the art can flexibly adjust this according to the desired fertilizer formulation. That is, the molten material supplied to the fluidized bed granulator 200 can be the same as or different from the urea molten material sprayed in the granulation tower 100, and can be flexibly adjusted according to actual conditions to produce large-particle urea products or medium- and large-particle compound fertilizer products mainly composed of urea.

[0061] Specifically, such as Figure 1 As shown, the fertilizer production equipment provided in this embodiment of the invention also includes a feeding pipe and a spraying device. The feeding pipe is connected to a fluidized bed granulator 200 and is used to transport the molten material to the fluidized bed granulator 200 for granulation. A conveying pump 201 can also be installed on the feeding pipe to increase hydraulic pressure and ensure continuous feeding and atomization. The spraying device is located at the connection between the feeding pipe and the fluidized bed granulator 200 and is used to atomize and spray the molten material into the fluidized bed. That is, the molten material is transported to the fluidized bed granulator 200 through the feeding pipe and the conveying pump 201, and then atomized and sprayed into the fluidized bed by the spraying device. The molten material is uniformly atomized by the spraying device and, under the action of the fluidizing air and the atomizing air, is evenly distributed within the fluidized bed, thereby uniformly covering and crystallizing the seed crystal surface to form a film, achieving film-like atomized granulation.

[0062] The advantage of using film atomization granulation in the fluidized bed granulator 200 is that it generates less dust during the granulation process than other fluidized bed granulation equipment, making it more environmentally friendly.

[0063] like Figure 1 As shown, the fluidizing blower 212 is in fluid communication with the fluidized bed granulator 200. The fluidizing blower 212 is used to pressurize air to generate fluidizing air. The fluidizing blower 212 provides sufficient gas flow velocity and pressure to ensure that the seed crystals and material within the bed remain in a fluidized state, promoting heat transfer. In other words, the fluidizing air is introduced into the fluidized bed through the gas inlet, keeping the seed crystals and material in a fluidized state under the agitation and impact of the gas. This fluidized state increases the contact between the seed crystals and material, thereby achieving the granulation process. The fluidizing air also helps to achieve a uniform particle distribution, resulting in particles of uniform size and good sphericity.

[0064] By adjusting the power and speed of the fluidizing fan 212, the flow rate and pressure of the fluidizing air can be controlled to adapt to different granulation processes and requirements. In other embodiments, the device for generating the fluidizing air can also be a compressed air system, and the required fluidizing air can be generated by adjusting the output pressure and flow rate of the compressed air.

[0065] like Figure 1 As shown, the fertilizer production equipment provided in this embodiment also includes a fluidizing air preheater 213. The fluidizing air preheater 213 is connected to the fluidizing blower 212, and the output end of the fluidizing air preheater 213 is connected to the fluidized bed granulator 200.

[0066] The fluidizing air preheater 213 is used to preheat the fluidizing air. Inside the fluidized bed granulator 200, the incoming fluidizing air comes into contact with the material. If the gas temperature is low at this time, condensation may occur at the contact point between the gas and the particles, affecting the normal operation of the fluidized bed. Preheating the fluidizing air can raise the gas temperature to a suitable operating temperature, ensuring the smooth progress of the granulation process and improving efficiency and product quality.

[0067] The fertilizer production equipment provided in this embodiment of the invention also includes a first heat exchanger 241, which is disposed between the fluidizing blower 212 and the fluidizing air preheater 213, and the first heat exchanger 241 is in fluid communication with the granulation tower 100.

[0068] The first heat exchanger 241 is fluidly connected to the granulation tower 100, allowing for the recovery of heat energy from the high-temperature exhaust gas exiting the granulation tower 100. Preferably, the first heat exchanger 241 is connected to a higher part of the granulation tower 100 to avoid affecting the delivery of seed crystals to the fluidized bed granulator 200. When the cold fluidizing air passes through the first heat exchanger 241, it absorbs some heat energy, thus reducing the energy required to reach the fluidizing air preheater 213 and saving energy.

[0069] The first heat exchanger 241 can take different forms, such as shell and tube type, plate type, spiral type, tube bundle type, etc., as long as it can achieve the purpose of heat exchange.

[0070] like Figure 1 As shown, the atomizing fan 222 is in fluid communication with the fluidized bed granulator 200. The atomizing fan 222 is used to pressurize the air to generate atomized air. By pressurizing, the airflow velocity can be increased, and the generated atomized air can promote the dispersion of material droplets, improving granulation efficiency. At the same time, it improves the uniformity of the airflow, making the sprayed droplets more evenly distributed and avoiding uneven spraying or splashing. In addition, it can also increase the droplet range, thereby achieving a wider spray range and a more uniform coverage on the particle surface, which helps to form product particles with good roundness and high strength.

[0071] like Figure 1 As shown, the fertilizer production equipment provided in this embodiment also includes an atomizing air preheater 223. The atomizing air preheater 223 is connected to the atomizing fan 222, and the output end of the atomizing air preheater 223 is connected to the fluidized bed granulator 200.

[0072] The atomizing air preheater 223 is used to increase the thermal energy of the gas in the atomizing air, which is beneficial for the liquid to be atomized into finer droplets. High-temperature atomizing air can increase the kinetic energy of the droplets, thereby increasing the speed and uniformity of the droplets covering the particle surface, and improving the particle formation speed and quality.

[0073] In this embodiment, the high-temperature and high-pressure atomizing air formed by the atomizing fan 222 and the atomizing air preheater 223 can be set to have a higher temperature and air pressure than the fluidizing air mentioned above, so as to ensure that the material droplets are evenly distributed, which is beneficial to granulation.

[0074] The fertilizer production equipment provided in this embodiment of the invention also includes a second heat exchanger 242, which is disposed between the atomizing fan 222 and the atomizing air preheater 223, and the second heat exchanger 242 is in fluid communication with the granulation tower 100.

[0075] The second heat exchanger 242 is configured similarly to the first heat exchanger 241 described above, and also serves the purpose of heat recovery, which will not be elaborated upon here. It is worth noting that the high-temperature exhaust gas from the fluidized bed granulator 200 can also be connected to both the first and second heat exchangers 241 to increase energy utilization and save energy consumption.

[0076] In some embodiments, the fluidized bed granulator 200 includes a cooling device. The cooling device is a small cooler integrated within the fluidized bed granulator, located at the discharge port where the fluidized bed granulator 200 connects to the screen 310, and is used to pre-cool the product particles before screening. By providing the cooling device, the temperature of the product particles can be initially reduced, promoting particle formation and ensuring the screening effect of the screen 310.

[0077] A sieve 310 is located downstream of the fluidized bed granulator 200 and is used to sieve the product particles formed within the fluidized bed granulator 200. In this embodiment, the sieve 310 is a safety sieve. A safety sieve is also known as a vibrating safety sieve or a vibrating screen.

[0078] The safety screen features a sealed design to prevent material leakage and dust spread, ensuring a clean production environment and employee safety. It employs a vibrating device to sieve materials through a vibrating screen, improving screening efficiency and accelerating the production process. The screening precision can be adjusted as needed to meet different particle size requirements by changing the screen size.

[0079] In other embodiments, the sieve 310 may also be a cyclone sieve, an airflow sieve, etc., to achieve a similar sieving function as described above.

[0080] Through sieving by the sieve 310, qualified product particles with sufficiently large particle sizes remain inside the sieve 310, while unqualified products with insufficient particle size are separated, thereby improving product quality and performance and making the product more in line with quality requirements. At the same time, by adjusting the mesh size of the sieve 310, the particle size of the product can be flexibly adjusted to adapt to market demands.

[0081] The product cooler 400 is connected to the screener 310 and is used to cool the qualified product particles screened out, thereby meeting the product quality requirements, avoiding overheating loss, and meeting the needs of subsequent processing, facilitating subsequent packaging and sealing.

[0082] like Figure 1 As shown, the fertilizer production equipment provided in this embodiment of the invention also includes a recycler 320. The input end of the recycler 320 is connected to the screen 310, and the output end of the recycler 320 is connected to the fluidized bed granulator 200.

[0083] The recycler 320 is used to recover the substandard small particles screened out by the screener 310 and transport them back to the fluidized bed granulator 200 for repeated fluidized bed granulation to increase the particle size. Reprocessing substandard products reduces waste generation and emissions, which is beneficial to environmental protection. It also improves production efficiency and brings greater economic benefits.

[0084] In this embodiment, the collector 320 is a bucket elevator. A bucket elevator is a common material handling device used for vertical or near-vertical material transport. The bucket elevator consists of a large bucket container and a transmission device. By driving a conveyor belt or chain equipped with buckets to move up and down, it lifts the small particles that have fallen through the screen 310 from a lower position to a higher position and transports them back to the fluidized bed granulator 200 for reprocessing.

[0085] In addition, the recycler 320 can also be a screw conveyor or other device suitable for conveying materials, which can be selected by those skilled in the art according to their needs.

[0086] According to the fertilizer production equipment provided by the present invention, an exhaust gas purification device is also included, which is connected to the granulation tower 100 and / or the fluidized bed granulator 200.

[0087] The exhaust gas purification device is used to reduce pollutants in the exhaust gas to within the limits of environmental emission standards, thereby protecting the environment and human health. In different embodiments, exhaust gas purification devices can be installed at the granulation tower 100 and the fluidized bed granulator 200 respectively, or the exhaust gases from the granulation tower 100 and the fluidized bed granulator 200 can be piped to the same exhaust gas purification device for treatment.

[0088] The exhaust gas purification device includes a scrubber 231 and an induced draft fan 232. The input end of the scrubber 231 is connected to the granulation tower 100 and / or the fluidized bed granulator 200; the induced draft fan 232 is connected to the output end of the scrubber 231.

[0089] The scrubber 231 is directly connected to the granulation tower 100 and / or the fluidized bed granulator 200, and is used to treat gaseous pollutants in the exhaust gas. It purifies and treats the exhaust gas by passing the exhaust gas into the scrubbing liquid, where the gaseous pollutants react with or are absorbed by the components of the scrubbing liquid through chemical reactions or physical absorption.

[0090] The induced draft fan 232 is used to drive and guide the exhaust gas during the treatment process and is connected to the output end of the scrubber 231. The main function of the induced draft fan 232 is to generate airflow to guide the exhaust gas from the granulation tower 100 and / or the fluidized bed granulator 200 to the scrubber 231, and then discharge the treated exhaust gas from the scrubber 231 into the atmosphere. The induced draft fan 232 ensures sufficient flow and contact of the exhaust gas during the treatment process, thereby improving treatment efficiency. The induced draft fan 232 can also be used to control the system's airflow and pressure, ensuring the stability and reliability of the entire treatment process.

[0091] The following is combined Figure 2 This paper describes a fertilizer production method based on fertilizer production equipment.

[0092] Fertilizer production methods include:

[0093] The molten urea is granulated in the granulation tower 100 and then conveyed to the fluidized bed granulator 200 as seed crystals.

[0094] The molten material is transported to the fluidized bed granulator 200 through the feed pipe, fluidizing air is delivered to the fluidized bed granulator 200 through the fluidizing fan 212, and atomizing air is delivered to the fluidized bed granulator 200 through the atomizing fan 222.

[0095] The formed product particles are screened by the screener 310;

[0096] The qualified product particles screened out are cooled by the product cooler 400.

[0097] The unqualified product particles separated by the recycling unit 320 are transported back to the fluidized bed granulator 200.

[0098] Specifically, in the granulation tower 100, molten urea is sprayed from a height and allowed to cool and crystallize naturally, preparing it into small, highly spherical particles, which are then transported as seed crystals to the fluidized bed granulator 200. These seed crystals can provide an ordered structure, promoting the subsequent particle formation process.

[0099] Then, the molten material is fed into the fluidized bed granulator 200 through the feed pipe, and sprayed into the fluidized bed granulator 200 through the spraying device. A delivery pump 201 can be installed on the feed pipe to increase the pressure and accurately deliver the molten material to the processing area of ​​the fluidized bed granulator 200.

[0100] Fluidizing blower 212 generates airflow, which is transported through pipelines to fluidized bed granulator 200 to form a fluidized state. Fluidizing air is key to maintaining the fluidized state of the particles, allowing them to be fully mixed and exchange heat in the fluidized bed.

[0101] The atomizing fan 222 generates an atomized airflow, which is then conveyed to the fluidized bed granulator 200. The atomized airflow carries fine droplets of the material solution, which are uniformly dispersed in the fluidized bed, while simultaneously wetting the particles and promoting particle growth.

[0102] After a certain growth process, the particles in the fluidized bed granulator 200 form product particles of a certain size range with good roundness and strength. These particles are then screened by the sieve 310 to separate qualified product particles that meet the size requirements from unqualified product particles that do not meet the size requirements.

[0103] The qualified product particles screened out are cooled by the product cooler 400 to the required temperature in order to meet product quality requirements and subsequent processing needs.

[0104] After the screener 310 separates the non-conforming product particles, it is transported back to the fluidized bed granulator 200 through the collector 320 so that they can participate in the fluidized bed granulation process again, thereby minimizing waste and improving particle utilization.

[0105] Through the above steps, high-quality large-particle products with uniform size and shape, good roundness, and high strength can be obtained. Furthermore, by changing the composition of the molten material, different fertilizer formulations can be easily produced. Specifically, when the molten material is urea molten material, large-particle urea products can be produced; when the molten material is compound fertilizer molten material, medium- and large-particle compound fertilizer products with urea as the main component can be produced. Moreover, by adjusting the composition of the molten material, the types of medium- and large-particle compound fertilizer products with urea as the main component can be adjusted, thereby meeting diverse market demands.

[0106] The present invention will be described in detail below through several embodiments.

[0107] like Figure 3As shown, a first aspect of the present invention provides a fertilizer production equipment and method. Specifically, a pressurized urea molten liquid (95%–99.7% by mass) is formed into small, well-rounded particles by fluidized air in a granulation tower 100, and cooled to 60–70°C. These particles are then transported via differential pressure or belt conveyor to a fluidized bed granulator 200 and a cooler as seed crystals. The urea molten liquid is pumped to the fluidized bed granulator 200 by a transfer pump 201, where it is sprayed onto the seed crystal surface to enlarge it for fluidized granulation. Air is pressurized by an atomizing fan 222, heated by an atomizing air preheater 223, and then sent to the fluidized bed granulator 200. Air is also pressurized by a fluidizing fan 212, heated by a fluidizing air preheater 213, and then sent to the fluidized bed granulator 200. Gas discharged from the fluidized bed granulator 200 is scrubbed and then discharged into the atmosphere. After the urea product from the fluidized bed granulator 200 is screened by a safety screen, the qualified urea product is cooled by the product cooler 400 and output as large granule urea product. The unqualified small granules are sent back to the fluidized bed granulator 200 by a bucket elevator to be used as seed crystals for further granulation.

[0108] The fertilizer production equipment and method proposed in this embodiment can produce high-quality large-particle urea products with uniform size and shape, good roundness, and high strength, while reducing waste generation and improving production efficiency.

[0109] like Figure 4 As shown, a second aspect of the present invention provides a fertilizer production apparatus and method. The difference from the first aspect is that the exhaust gas discharged from the granulation tower 100 is combined with the gas discharged from the fluidized bed granulator 200, and both are discharged after being washed and dust-removed by a scrubber.

[0110] This embodiment, based on the first aspect embodiment, also has the advantages of low exhaust gas treatment cost and high efficiency.

[0111] like Figure 5 As shown, a third aspect of the present invention provides a fertilizer production apparatus and method. The difference from the first aspect is that the molten material fed to the fluidized bed granulator 200 is a compound fertilizer molten liquid.

[0112] The fertilizer production equipment and method proposed in this embodiment can produce urea-based medium and large granular compound fertilizer products with uniform size and shape, good roundness, and high strength. The composition and proportion of the compound fertilizer melt can be adjusted according to the application scenario. By changing the composition of the compound fertilizer melt, different formulations of urea-based medium and large granular compound fertilizer products can be easily produced, thereby meeting diverse market demands.

[0113] like Figure 6As shown, a fourth aspect embodiment of the present invention provides a fertilizer production apparatus and method. The difference from the first aspect embodiment is the addition of a first heat exchanger 241 and a second heat exchanger 242.

[0114] By setting up the first heat exchanger 241 and the second heat exchanger 242, a portion of the heat in the tail gas of the granulation tower 100 can be recovered, improving energy utilization. After the fluidizing air passes through the first heat exchanger 241 and the atomizing air passes through the second heat exchanger 242, the temperature is initially increased, thus reducing the energy required to reach the preheater and saving energy.

[0115] In this embodiment, the exhaust gas from the granulation tower 100 passes through the second heat exchanger 242 and the first heat exchanger 241 sequentially to reduce piping and save costs. In other embodiments, the exhaust gas from the granulation tower 100 can be routed to the first heat exchanger 241 and the second heat exchanger 242 separately to improve energy utilization. As an improvement, an exhaust gas treatment device can be added at the end, where the exhaust gas is treated after heat exchange with the first heat exchanger 241 and the second heat exchanger 242 before being discharged, thus increasing environmental friendliness.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fertilizer production plant, characterized in that, The fertilizer production equipment comprises: a fluidized bed granulator suitable for forming product particles; a granulation tower arranged upstream of the fluidized bed granulator; a fluidizing fan in fluid communication with the fluidized bed granulator; an atomizing fan in fluid communication with the fluidized bed granulator; a sifter arranged downstream of the fluidized bed granulator; a product cooler connected to the sifter; an atomizing fan preheater connected to the atomizing fan, an output end of the atomizing fan preheater being connected to the fluidized bed granulator; a second heat exchanger arranged between the atomizing fan and the atomizing fan preheater, the second heat exchanger being in fluid communication with the granulation tower. The fertilizer production equipment further comprises: a feed pipe in communication with the fluidized bed granulator; a liquid spraying device arranged at the communication between the feed pipe and the fluidized bed granulator, the liquid spraying device being suitable for atomizing a melt of material to form film-shaped particles; a fluidizing fan preheater connected to the fluidizing fan, an output end of the fluidizing fan preheater being connected to the fluidized bed granulator.

2. The fertilizer production apparatus according to claim 1, characterized by The fertilizer production equipment further comprises a recycler; an input end of the recycler being connected to the sifter, an output end of the recycler being connected to the fluidized bed granulator.

3. The fertilizer production apparatus according to claim 1, characterized by, The fertilizer production equipment further comprises a first heat exchanger arranged between the fluidizing fan and the fluidizing fan preheater, the first heat exchanger being in fluid communication with the granulation tower.

4. The fertilizer production apparatus according to any one of claims 1 to 3, characterized in that, The fertilizer production equipment further comprises a tail gas purification device connected to the granulation tower and / or the fluidized bed granulator.

5. The fertilizer production apparatus according to claim 4, characterized in that, The tail gas purification device comprises: a scrubber, an input end of the scrubber being connected to the granulation tower and / or the fluidized bed granulator; an induced draft fan connected to an output end of the scrubber.

6. The fertilizer production apparatus according to any one of claims 1 to 3, characterized by, The fluidized bed granulator is connected to the sifter through a discharge port, and the fluidized bed granulator comprises a cooling device arranged at the discharge port.

7. A fertilizer production method based on the fertilizer production apparatus according to any one of claims 1 to 6, characterized by, The fertilizer production equipment comprises: preparing a melt of urea into particles through the granulation tower and conveying the particles to the fluidized bed granulator as seed crystals; conveying a melt of material to the fluidized bed granulator through a feed pipe, conveying fluidizing air to the fluidized bed granulator through the fluidizing fan, and conveying atomizing air to the fluidized bed granulator through the atomizing fan; sifting the formed product particles through the sifter; cooling the qualified product particles sifted out through the product cooler; conveying the unqualified product particles sifted out back to the fluidized bed granulator through the recycler.

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