Urea sulfate formaldehyde compound fertilizer production equipment

Abstract

The utility model relates to the technical field of compound fertilizer production equipment, and discloses urea sulfate formaldehyde compound fertilizer production equipment which comprises a urea formaldehyde reaction unit, an ammonium sulfate reaction unit, a granulation unit and a post-treatment unit which are communicated through pipelines, and the post-treatment unit comprises a primary dryer and a secondary dryer which are communicated; the granulation unit comprises a batching tank and a rotary drum granulator which are communicated with each other, and the outlet end of the rotary drum granulator is communicated with the primary dryer; the ammonium sulfate reaction unit comprises a tubular reactor, and the outlet end of the tubular reactor is communicated with a rotary drum granulator; the urea formaldehyde reaction unit comprises a reaction tank and a middle tank which are communicated, an inlet end pipeline of the reaction tank is communicated with the urea bin and the formaldehyde tank, the middle tank is communicated with a discharge pipe, and the other end of the discharge pipe extends into the secondary dryer and is provided with a plurality of nozzles. According to the scheme, the sulfuric acid slurry and the urea formaldehyde solution are added in different production stages of the compound fertilizer, so that the influence of sulfuric acid on the structural stability of urea formaldehyde is effectively reduced, and the slow-release effect of the urea formaldehyde slow-release compound fertilizer is improved.

Description

Technical Field

[0001] This invention relates to the field of compound fertilizer production equipment technology, specifically to a compound fertilizer production equipment for urea-formaldehyde sulfate. Background Technology

[0002] Urea-formaldehyde slow-release fertilizer is a combination of sulfuric acid, urea, and formaldehyde, primarily used to provide nitrogen for plant growth. Its key feature is the slow-release structure formed by the reaction of urea and formaldehyde, allowing nutrients to be released gradually, meeting the long-term needs of crops, reducing nutrient loss, and improving utilization efficiency.

[0003] Existing technology CN101857513A discloses a one-step spray granulation method for preparing long-acting slow-release compound fertilizer. This method involves mixing formaldehyde and urea to form a slurry, then introducing solid materials such as nitrogen, phosphorus, and potassium into a granulation device. The slurry is mixed with sulfuric acid and sprayed onto the solid materials for granulation. Simultaneously, ammonia is introduced for neutralization to obtain granular compound fertilizer. Existing technology CN118530059A discloses a method for continuously preparing urea-formaldehyde slow-release fertilizer using a tubular reactor. This method involves preparing an acidic urea-formaldehyde solution in a tubular reactor. Specifically, urea, formaldehyde, and alkali are added at the front end of the tubular reactor, the pH is adjusted to 7, and the reaction is heated to obtain a urea-formaldehyde solution. Acid is added in the middle section of the tubular reactor to adjust the pH to acidic and react to obtain a reaction solution. After filtration, the filter cake is dried to obtain the acidic urea-formaldehyde slow-release fertilizer.

[0004] However, because urea-formaldehyde is only stable under alkaline conditions, it is unstable under acidic or high humidity conditions and is prone to decomposition. The following technical problems still exist in the prior art: (1) The equipment in the prior art CN118530059A and prior art CN101857513A can only produce urea-formaldehyde under neutral or acidic conditions, resulting in poor stability of the obtained urea-formaldehyde and significantly reducing the product yield; (2) The prior art CN118530059A adds acid in the middle section of the tubular reactor, which decomposes the urea-formaldehyde in the reaction liquid, further reducing the urea-formaldehyde content in the product and reducing the slow release effect; (3) The equipment in the prior art CN101857513A mixes the slurry with sulfuric acid and sprays it onto the solid material for granulation, which makes it easy for sulfuric acid and slurry to reduce the stability of urea-formaldehyde during the mixing process, affecting the slow release effect of urea-formaldehyde in compound fertilizer.

[0005] Therefore, developing a production equipment for sulfuric acid urea-formaldehyde compound fertilizer that allows for the step-by-step addition of sulfuric acid and urea-formaldehyde not only effectively compensates for the shortcomings of existing technologies, but also effectively avoids the direct contact of sulfuric acid with urea-formaldehyde, which would reduce the slow-release effect of urea-formaldehyde. This is of great significance for improving the slow-release effect and extending the slow-release period of sulfuric acid urea-formaldehyde compound fertilizer to promote crop growth. Summary of the Invention

[0006] The present invention aims to provide a production equipment for urea-formaldehyde sulfate compound fertilizer to solve the technical problem that when existing production equipment mixes sulfuric acid and urea-formaldehyde and then filters, dries, or sprays and granulates, the urea-formaldehyde slow-release effect of the produced urea-formaldehyde sulfate compound fertilizer is easily reduced.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a urea-formaldehyde compound fertilizer production equipment, comprising a urea-formaldehyde reaction unit, an ammonium sulfate reaction unit, a granulation unit, and a post-processing unit connected by pipelines; the post-processing unit comprising a primary dryer and a secondary dryer connected by pipelines in sequence; the granulation unit comprising a batching tank and a rotary drum granulator connected by pipelines, the outlet end of the rotary drum granulator being connected to the primary dryer; the ammonium sulfate reaction unit comprising a tubular reactor, the inlet end of which is connected by pipelines to a sulfuric acid tank and a phosphate ammonium dissolving tank, the outlet end of which is connected by pipelines to the rotary drum granulator; the urea-formaldehyde reaction unit comprising a reaction tank and an intermediate tank connected by pipelines, the inlet end of which is connected by pipelines to a urea silo and a formaldehyde tank, the intermediate tank being connected by a discharge pipe, the other end of which extends into the secondary dryer and is equipped with several nozzles.

[0008] The principle behind this equipment's production of urea-formaldehyde sulfate compound fertilizer is as follows:

[0009] First, sulfuric acid, monoammonium phosphate, and ammonia gas are reacted in a tubular reactor to form a sulfuric acid slurry. Urea and formaldehyde are then reacted in an alkaline solution to form a urea-formaldehyde solution. The sulfuric acid slurry is then mixed with other nitrogen, phosphorus, and potassium raw materials in a rotary drum granulator for granulation. After processing in a primary dryer, the compound fertilizer is transported to a secondary dryer for further drying. At this point, the urea-formaldehyde solution from the intermediate tank is sprayed onto the surface of the compound fertilizer, coating it to obtain a slow-release urea-formaldehyde sulfate compound fertilizer.

[0010] The advantages of this solution are:

[0011] 1. Compared to existing production equipment that mixes sulfuric acid and urea-formaldehyde and then filters, dries, or sprays and granulates, which can easily reduce the slow-release effect of urea-formaldehyde sulfate compound fertilizer, this solution uses equipment that mixes the slurry obtained by reacting sulfuric acid and ammonium phosphate with other nitrogen, phosphorus, and potassium raw materials to granulate the compound fertilizer. The urea-formaldehyde solution is then sprayed onto the compound fertilizer after secondary drying, effectively avoiding the strong acidity of sulfuric acid from affecting or damaging the stability of urea-formaldehyde, thereby improving the slow-release effect of the urea-formaldehyde sulfate compound fertilizer.

[0012] 2. This solution involves mixing sulfuric acid slurry obtained by reacting sulfuric acid and ammonium phosphate with other nitrogen, phosphorus and potassium raw materials to form granules, which effectively enriches the types and contents of elements in the compound fertilizer. It can also encapsulate sulfuric acid inside the compound fertilizer and then coat the slow-release surface with urea-formaldehyde solution. This allows the compound fertilizer to slowly release nitrogen, phosphorus and potassium elements while slowly releasing sulfuric acid after application, effectively regulating soil pH and improving alkaline soil.

[0013] 3. Compared to the method of spraying urea-formaldehyde solution onto compound fertilizer in the primary dryer, which can easily lead to changes in the particle size of the compound fertilizer and reduce production efficiency, this solution sprays the urea-formaldehyde solution onto the surface of the compound fertilizer in the secondary dryer. This effectively coats the compound fertilizer while preventing changes in particle size, thus ensuring its uniformity. The applicant's analysis is that the preliminary drying of the compound fertilizer in the primary dryer effectively reduces its moisture content and increases its strength. Then, when it is transported to the secondary dryer for urea-formaldehyde solution spraying, it will not break or detach due to the impact of the urea-formaldehyde solution spraying, thus effectively ensuring the uniformity of the compound fertilizer particle size and improving production efficiency.

[0014] Preferably, as an improvement, the post-processing unit further includes a first grading screen, a rotary drum cooler, a second grading screen, a plate cooler, a wrapping machine, and a finished product packaging machine connected in sequence, with the feed end of the first grading screen connected to the discharge end of the secondary dryer.

[0015] Technical Effects: This solution, employing the above-mentioned setup, facilitates the screening, cooling, coating, and packaging of dried compound fertilizer to obtain the finished compound fertilizer product. This solution utilizes an alternating two-stage screening and two-stage cooling process. The first stage screen removes excessively small particles, ensuring relatively uniform particle size before entering the cooling stage. The rotary drum cooler initially cools the particles, preventing them from clumping or deforming due to high temperatures. A second screening after cooling further ensures the uniformity of the final product's particles. Finally, a plate cooler further cools the particles, ensuring they reach the ideal temperature and physical state, thus improving product quality.

[0016] Preferably, as an improvement, the bottom pipes of the first and second grading screens are connected to a return crusher, the discharge end of the return crusher is connected to a return pipe, and the other end of the return pipe is connected to a rotary drum granulator.

[0017] Technical benefits: The above-mentioned setup facilitates the return of unqualified compound fertilizer particles after screening, which can then be crushed and reused for granulation, effectively reducing material waste.

[0018] Preferably, as an improvement, it also includes a dust removal unit, wherein the top of the batching tank, the rotary drum granulator, the reaction tank, the intermediate tank, the primary dryer, the secondary dryer and the rotary drum cooler are all provided with exhaust pipes, which are connected to the dust removal unit pipeline.

[0019] Technical benefits: The above-mentioned setup facilitates the collection and treatment of exhaust gases or dust generated during the production process.

[0020] Preferably, as an improvement, the top of the first grading screen, the second grading screen, the plate cooler, the coating machine, and the return crusher are connected to a dust removal pipe, and the other end of the dust removal pipe is connected to the air inlet pipe of the rotary drum cooler.

[0021] Technical benefits: This solution collects the particulate dust generated in the first and second grading screens, plate coolers, coating machines, and return crushers and feeds it into the rotary drum cooler. By flushing it with the compound fertilizer in the rotary drum cooler, it can effectively recover dust particles and reduce the overall amount of dust generated, thereby reducing the energy consumption of dust treatment.

[0022] Preferably, as an improvement, the inlet end of the tubular reactor is also connected to a gaseous ammonia tank, the inlet end of the ammonium phosphate dissolving tank is connected to a monoammonium phosphate storage tank, and the ammonium phosphate dissolving tank is equipped with a heating device.

[0023] Technical effect: The above-mentioned setup is used in this scheme. First, monoammonium phosphate is dissolved in an ammonium phosphate dissolving tank to make ammonium phosphate slurry. Then, it is introduced into a tubular reactor with sulfuric acid and gaseous ammonia in proportion. The exothermic reaction generates a mixed slurry of ammonium sulfate and diammonium phosphate, which dilutes the sulfuric acid and reduces its corrosiveness as much as possible.

[0024] Preferably, as an improvement, the inlet end of the reaction tank is also connected to a water storage tank and a flake caustic soda silo, and the reaction tank is equipped with a heating device and a stirring device.

[0025] Technical effect: The above-mentioned setup facilitates the addition of urea, formaldehyde, water, and caustic soda into the reaction tank in a certain proportion and order to obtain a stable urea-formaldehyde solution, thereby improving the slow-release effect of the compound fertilizer product obtained by spraying it.

[0026] Preferably, as an improvement, a cooling pipe is connected between the reaction tank and the intermediate tank, and a graphite cooler is connected to the cooling pipe.

[0027] Technical benefits: The above-mentioned setup facilitates rapid cooling of the urea-formaldehyde solution as needed, thereby improving production efficiency.

[0028] Preferably, as an improvement, the mixing tank pipeline is connected to a white mud tank, an ammonium sulfate tank, a urea tank, and a potassium chloride tank.

[0029] Technical benefits: The above-mentioned setup facilitates the preparation of raw materials based on the elemental composition of the compound fertilizer being produced. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the urea-formaldehyde compound fertilizer production equipment in Embodiment 1 of the present invention.

[0031] Figure 2 This is a schematic diagram of the post-processing unit in Embodiment 1 of the present invention.

[0032] Figure 3 This is a schematic diagram of the urea-formaldehyde reaction unit in Embodiment 1 of the present invention. Detailed Implementation

[0033] The following detailed description illustrates the specific implementation method:

[0034] The reference numerals in the accompanying drawings include: 1. First grading screen; 2. Second grading screen; 3. Return crusher; 31. Return pipe; 4. Plate cooler; 5. Coating machine; 6. Drum cooler; 61. Dust removal pipe; 7. Reaction tank; 71. Water inlet pipe; 711. Water inlet valve; 72. Air inlet pipe; 721. Air inlet valve; 73. Feed inlet; 74. Liquid outlet pipe; 741. Liquid outlet valve; 742. First conveying pump; 75. Agitator; 76. Thermometer; 77. pH meter; 78. Cooling pipe; 781. Cooling valve; 782. Third conveying pump; 8. Intermediate tank; 81. Discharge pipe; 811. Discharge valve; 812. Second conveying pump; 9. Tail gas pipe.

[0035] Example 1

[0036] This solution provides a urea sulfate-formaldehyde compound fertilizer production equipment, as shown in the attached diagram. Figure 1 As shown: It includes a urea-formaldehyde reaction unit, an ammonium sulfate reaction unit, a granulation unit, a post-treatment unit, and a dust removal unit.

[0037] The granulation unit includes a batching tank and a rotary drum granulator connected by pipes. The inlet end of the batching tank is connected to a white mud silo, an ammonium sulfate silo, a urea silo, and a potassium chloride silo. The outlet end of the rotary drum granulator is connected to the post-processing unit.

[0038] The post-processing unit includes a primary dryer, a secondary dryer, a first grading screen 1, a rotary drum cooler 6, a second grading screen 2, a plate cooler 4, a wrapping machine 5, and a finished product packaging machine, all connected by sequential pipes. The inlet of the primary dryer is connected to the outlet of the rotary drum granulator. The primary dryer, secondary dryer, and rotary drum cooler 6 have identical structures, the difference being that the dryer uses hot air as the drying source, while the cooler uses cold air as the cooling source. The bottom pipes of the first grading screen 1 and the second grading screen 2 are connected to a return crusher 3. The outlet of the return crusher 3 is connected to a return pipe 31, the other end of which is connected to the rotary drum granulator.

[0039] The ammonium sulfate reaction unit includes a tubular reactor. The inlet of the tubular reactor is connected to a sulfuric acid tank, a gaseous ammonia tank, and a phosphate dissolving tank. The inlet of the phosphate dissolving tank is connected to a monoammonium phosphate storage tank. The phosphate dissolving tank is equipped with a heating device; for reference, a coil heater is installed inside the phosphate dissolving tank. The outlet of the tubular reactor is connected to a rotary drum granulator.

[0040] The urea-formaldehyde reaction unit includes a reaction tank 7 and an intermediate tank 8. The inlet pipe of the reaction tank 7 is connected to a urea tank, a formaldehyde tank, a water storage tank, and a caustic soda flake tank. An outlet pipe 74 and a cooling pipe 78 connect the reaction tank 7 and the intermediate tank 8. A graphite cooler is installed on the cooling pipe 78. The intermediate tank 8 is connected to a discharge pipe 81, the other end of which extends into a secondary dryer and is equipped with several nozzles.

[0041] As shown in the diagram (dashed lines), the dust removal unit includes several dust collectors. The tops of the feeding trough, rotary drum granulator, reaction tank 7, intermediate tank 8, primary dryer, secondary dryer, and rotary drum cooler 6 are all equipped with exhaust pipes 9, which are connected to the dust collector piping. Depending on site requirements, the dust collectors include Venturi scrubbers, cyclone dust collectors, and baghouse dust collectors to effectively treat different types of collected exhaust gases and dust. Furthermore, to recover and reuse some of the dust, such as… Figure 2 As shown, the top of the first grading screen 1, the second grading screen 2, the plate cooler 4, the coating machine 5, and the return crusher 3 are connected to a dust removal pipe 61. The other end of the dust removal pipe 61 is connected to the air inlet pipe of the rotary drum cooler 6, which facilitates the timely recovery of compound fertilizer dust generated during screening, cooling, and coating processes, reduces dust waste, and also reduces the processing energy consumption of the associated dust collectors in the dust removal unit.

[0042] This solution also includes essential pipes, pH metering pumps, valves, etc., connecting various devices. Taking the urea-formaldehyde reaction unit as an example, as shown in the diagram, reaction tank 7 is connected to a water inlet pipe 71, an air inlet pipe 72, a feed inlet 73, a liquid outlet pipe 74, and a cooling pipe 78. The water inlet pipe 71 is equipped with a water inlet valve 711, and the air inlet pipe 72 is equipped with an air inlet valve 721. The other end of the air inlet pipe 72 is connected to a formaldehyde tank. The feed inlet 73 is used to feed urea and caustic soda flakes. The liquid outlet pipe 74 is equipped with an liquid outlet valve 741 and a first transfer pump 742. The cooling pipe 78 is equipped with a cooling valve 781, a third transfer pump 782, and a graphite cooler. The other ends of both the liquid outlet pipe 74 and the cooling pipe 78 are connected to the intermediate tank 8. This solution allows for rapid cooling of the urea-formaldehyde solution in reaction tank 7 via the cooling pipe 78 and the graphite cooler, facilitating the handling of urgent situations requiring the spraying and coating of compound fertilizer with urea-formaldehyde solution within the factory area. Of course, even if rapid cooling of the urea-formaldehyde solution is not required, it can also be used as a replacement for the outlet pipe 74, so that continuous production of the reaction tank 7 can be achieved while the outlet pipe 74 and related equipment are being repaired.

[0043] The intermediate tank 8 is connected to a discharge pipe 81, which is equipped with a discharge valve 811 and a second conveying pump 812. Several nozzles are located at the other end of the discharge pipe 81, extending into the secondary dryer. This facilitates controlled spraying of urea-formaldehyde solution onto the surface of the compound fertilizer, encapsulating it to form a slow-release urea-formaldehyde compound fertilizer.

[0044] The reaction tank 7 is also equipped with a heater, a stirrer 75, a temperature and pH meter 77, and a pH meter 77. The heater can be a heating resistor or a jacket; in this embodiment, it is specifically a jacketed heater (not shown in the figure), used to heat the solution in the reaction tank 7. The stirrer 75 is used to stir the solution in the reaction tank 7 during the reaction process; the temperature and pH meter 77 is used to detect the temperature of the solution in the reaction tank 7, and the pH meter 77 is used to detect the pH of the solution in the reaction tank 7.

[0045] The tops of the reaction tank 7 and the intermediate tank 8 are respectively connected to the exhaust gas pipe 9, which is connected to the dust collector. In this embodiment, the dust collector is a Venturi scrubber, which collects and treats the exhaust gas in the reaction tank 7 and the intermediate tank 8.

[0046] A controller is also included, which is electrically connected to all electrical devices in the solution. The controller has several control buttons and a display screen showing temperature, pH, and the status of each electrical device, used for remote monitoring of the entire process. All electrical equipment used in this solution is existing equipment; its structure and function will not be described in detail here.

[0047] Specific implementation process:

[0048] Monoammonium phosphate (MAP) reaction and granulation: First, MAP is pumped into a MAP dissolving tank and dissolved in water at 90°C to prepare a MAP slurry. Then, sulfuric acid, the MAP slurry, and ammonia gas are pumped into one end of a tubular reactor in a specific ratio. As the mixture flows through the reactor, it reacts to form a sulfuric acid slurry containing sulfuric acid, phosphoric acid, diammonium hydrogen phosphate, ammonium sulfate, and water. The sulfuric acid slurry is then pumped into a rotary drum granulator pre-laid with a mixture (including ammonium sulfate, urea, potassium chloride, and white mud) to form compound fertilizer granules. The compound fertilizer granules are then conveyed to a primary dryer for preliminary drying, effectively reducing the water content and increasing the strength. Subsequently, they are conveyed to a secondary dryer for further drying, effectively reducing the moisture content of the compound fertilizer and increasing its strength.

[0049] Urea-formaldehyde reaction and coating: Water and urea are mixed and dissolved in reaction tank 7, then formaldehyde and caustic soda are introduced and heated to obtain a urea-formaldehyde solution. This solution is then transferred to intermediate tank 8 for later use. Reaction tank 7 is emptied to continue the production of the next batch of urea-formaldehyde solution. When the compound fertilizer granules are conveyed to the secondary dryer for drying, the urea-formaldehyde solution in intermediate tank 8 is transferred to the secondary dryer and sprayed onto the surface of the compound fertilizer granules, coating them to form a urea-formaldehyde sulfate slow-release compound fertilizer.

[0050] Post-processing: After further drying, the fertilizer is conveyed to the second grading screen for primary screening. The fine particles obtained from screening enter the return crusher 3 for further crushing, while the coarse particles enter the rotary drum cooler 6 for initial cooling. Subsequently, the cooled compound fertilizer is conveyed to the second grading screen for fine screening. The fine particles obtained from fine screening continue to enter the return crusher 3 for further crushing and then return to the rotary drum granulator via the return pipe 31 to mix and granulate with the next batch of material, reducing material waste. The coarse particles obtained from fine screening enter the plate cooler 4 for secondary cooling. The compound fertilizer granules obtained from secondary cooling are conveyed to the coating machine 5 for coating, and finally packaged in the finished product packaging machine to form bagged compound fertilizer products.

[0051] Throughout the implementation process, dust and exhaust gas from each piece of equipment are collected and treated via exhaust pipe 9. Between the various pieces of equipment in the post-processing unit, dust and exhaust gas generated from the first grading screen 1, the second grading screen 2, the return crusher 3, the plate cooler 4, and the coating machine 5 are recovered and used as a cooling source for the rotary drum cooler 6. This effectively recovers some of the dust material, thereby reducing the dust handling capacity of the dust collector, effectively reducing dust removal energy consumption, and improving production efficiency.

[0052] In summary, this method produces compound fertilizer by mixing the slurry obtained from the reaction of sulfuric acid and ammonium phosphate with other nitrogen, phosphorus, and potassium raw materials and granulating it. The urea-formaldehyde solution is then sprayed onto the compound fertilizer after secondary drying. This effectively avoids the strong acidity of sulfuric acid affecting or damaging the stability of urea-formaldehyde, thus improving the slow-release effect of the urea-formaldehyde sulfate compound fertilizer. Specifically, the slow-release period of the urea-formaldehyde sulfate compound fertilizer produced by this method can be extended to 100 days, allowing for a more sustained release of nitrogen nutrients and acidic substances into the soil. This not only provides nutrients in the early stages of plant growth but also meets the plant's growth needs in the later stages. Furthermore, it effectively regulates soil pH, reduces the risk of soil compaction, enhances soil aeration and water retention, and ultimately promotes crop yield increase.

[0053] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A production equipment for urea-formaldehyde sulfate compound fertilizer, characterized in that: The system includes a urea-formaldehyde reaction unit, an ammonium sulfate reaction unit, a granulation unit, and a post-treatment unit, all connected by pipes. The post-treatment unit includes a primary dryer and a secondary dryer connected by sequential pipes. The granulation unit includes a batching tank and a rotary drum granulator connected by pipes, with the outlet of the rotary drum granulator connected to the primary dryer. The ammonium sulfate reaction unit includes a tubular reactor, with its inlet connected by pipes to a sulfuric acid tank and a phosphate ammonium dissolving tank, and its outlet connected by pipes to the rotary drum granulator. The urea-formaldehyde reaction unit includes a reaction tank and an intermediate tank connected by pipes. The inlet of the reaction tank is connected by pipes to a urea silo and a formaldehyde tank, and the intermediate tank is connected by a discharge pipe. The other end of the discharge pipe extends into the secondary dryer and is equipped with several nozzles.

2. The urea-formaldehyde sulfate compound fertilizer production equipment according to claim 1, characterized in that: The post-processing unit also includes a first grading screen, a rotary drum cooler, a second grading screen, a plate cooler, a wrapping machine, and a finished product packaging machine connected in sequence. The feed end of the first grading screen is connected to the discharge end of the secondary dryer.

3. The urea-formaldehyde sulfate compound fertilizer production equipment according to claim 2, characterized in that: The bottom pipes of the first and second grading screens are connected to a return crusher, the discharge end of the return crusher is connected to a return pipe, and the other end of the return pipe is connected to a rotary drum granulator.

4. The urea-formaldehyde sulfate compound fertilizer production equipment according to claim 3, characterized in that: It also includes a dust removal unit. The top of the batching tank, the rotary drum granulator, the reaction tank, the intermediate tank, the primary dryer, the secondary dryer, and the rotary drum cooler are all equipped with exhaust pipes, which are connected to the dust removal unit pipeline.

5. The urea-formaldehyde sulfate compound fertilizer production equipment according to claim 4, characterized in that: The top of the first grading screen, the second grading screen, the plate cooler, the coating machine, and the return crusher are connected to a dust removal pipe, and the other end of the dust removal pipe is connected to the air inlet pipe of the rotary drum cooler.

6. The urea-formaldehyde sulfate compound fertilizer production equipment according to claim 1, characterized in that: The inlet end of the tubular reactor is also connected to a gaseous ammonia tank, and the inlet end of the ammonium phosphate dissolving tank is connected to a monoammonium phosphate storage tank. The ammonium phosphate dissolving tank is equipped with a heating device.

7. The urea-formaldehyde sulfate compound fertilizer production equipment according to claim 4, characterized in that: The inlet of the reaction tank is also connected to a water storage tank and a caustic soda ash storage tank. The reaction tank is equipped with a heating device and a stirring device.

8. The urea-formaldehyde sulfate compound fertilizer production equipment according to claim 7, characterized in that: A cooling pipe is connected between the reaction tank and the intermediate tank, and a graphite cooler is connected to the cooling pipe.

9. The urea-formaldehyde sulfate compound fertilizer production equipment according to claim 1, characterized in that: The mixing tank pipeline connects to a white mud silo, an ammonium sulfate silo, a urea silo, and a potassium chloride silo.

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