System and method for producing urea-ammonium phosphate fertilizer

Abstract

The invention discloses a urea-ammonium phosphate fertilizer production system and method.The urea-ammonium phosphate fertilizer production system comprises a pre-neutralization tank, a pelletizer, a dryer, a classifying screen, a crusher and a cooler, firstly phosphoric acid and ammonia are pre-neutralized in the pre-neutralization tank, and then ammonium phosphate slurry is sprayed on materials in the pelletizer for pelleting; an ammonia distributor is buried in the material, ammonium phosphate in the material is further ammoniated and neutralized, and a urea solution is sprayed on the material in the granulator; drying, screening and cooling the granulated urea-ammonium phosphate, and taking the qualified material as the target product urea-ammonium phosphate fertilizer. The adopted pre-neutralization tank is good in buffering performance, easy to operate and control and stable in product quality; ammonia can be liquid ammonia or gaseous ammonia, and an ammonia distributor is buried in materials of the pelletizer, so that secondary ammonia neutralization of ammonium phosphate is realized, the content of diammonium phosphate in ammonium phosphate is increased, the ratio of N / P2O5 in a target product urea ammonium phosphate is increased, the fertilizer application requirement of crops is met, and the fertilizer application effect is improved.

Description

Technical Field

[0001] The invention relates to a production system and method of urea ammonium phosphate fertilizer, belonging to the technical field of chemical industry. Background Art

[0002] Nutrients required for plant growth are primarily supplied by soil and fertilizer. Essential plant nutrients are defined by their three physiological characteristics: 1. They have a direct effect on plant growth or physiological metabolism; 2. Without any one of these elements, plants cannot grow and develop normally; and 3. Their physiological functions cannot be replaced by other elements. Sixteen essential plant nutrients are defined, including nitrogen (N) and phosphorus (P). Crops must contain greater than 2% nitrogen (N) and 0.4% phosphorus (P) by weight.

[0003] The low amounts of available nitrogen (N) and phosphorus (P) in the soil often become the primary limiting factor for plant yields, necessitating supplementation through fertilization. Currently produced ammonium phosphate (AMP) compound fertilizers are primarily monoammonium phosphate (MAP) and / or diammonium phosphate (DAP). AMP boasts a mature production process and high nutrient content, allowing for direct fertilizer use. However, the N / P2O5 ratio of DAP is too low, with MAP at approximately 1:5 and DAP at approximately 1:2.5, respectively, failing to meet crop requirements. Since plant yield is determined by the nutrient with the lowest relative abundance in the soil relative to plant needs, it is the limiting factor in plant yield. Without supplementation, even the addition of other nutrients will be difficult to achieve yield gains, reducing the economic benefits of fertilization. For example, in nitrogen-deficient soils, even the addition of phosphate fertilizers will be difficult to achieve yield gains. Summary of the Invention

[0004] The purpose of the present invention is to provide a production system and method for urea ammonium phosphate fertilizer with a large N / P2O5 ratio, so as to solve the technical problem that the N / P2O5 ratio of the existing ammonium phosphate fertilizer is too small and does not meet the requirements of crop fertilization.

[0005] The production system of urea ammonium phosphate fertilizer of the present invention adopts the following technical scheme: a production system of urea ammonium phosphate fertilizer, which includes a pre-neutralization tank, a granulator, a dryer, a grading screen, a crusher and a cooler, wherein a phosphoric acid inlet and an ammonia inlet are provided at the upper portion of the pre-neutralization tank, a phosphate ammonium outlet is provided at the bottom of the pre-neutralization tank, the phosphate ammonium outlet is connected to a phosphate ammonium solution distributor which is fed into the granulator, a urea solution distributor and an ammonia distributor are respectively provided above and below the phosphate ammonium solution distributor in the granulator, the material outlet of the granulator is communicated with the material inlet of the dryer, the material outlet of the dryer is connected with the material inlet of the grading screen, the grading screen has two-stage screens, and the grading screen is provided with a coarse particle outlet, a qualified particle outlet and a fine particle outlet from top to bottom, the coarse particle outlet is communicated with the material inlet of the crusher, the fine particle outlet and the material outlet of the crusher are communicated with the material inlet of the granulator, the qualified particle outlet is communicated with the material inlet of the cooler, and the product discharged from the material outlet of the cooler is the target product urea ammonium phosphate.

[0006] The dryer is a horizontal rotary cylinder structure, which includes a drying drum, a first material copying plate is provided on the inner wall of the drying drum, a first feed box and a first discharge box are provided at both ends of the drying drum, the material inlet of the dryer is arranged at the top of the first feed box, and the material outlet of the dryer is arranged at the bottom of the first discharge box. A hot air inlet is provided on the first feed box, and a first exhaust gas outlet is provided on the first discharge box.

[0007] The cooler adopts a drum cooler, which includes a horizontally arranged cooling drum, an inner wall of the cooling drum is provided with a second material copying plate, and two ends of the cooling drum are respectively provided with a second feed box and a second discharge box, the material inlet of the cooler is arranged at the top of the second feed box, and the material outlet of the cooler is arranged at the bottom of the second discharge box, a cold air inlet is provided on the second discharge box, and a second exhaust gas outlet is provided on the second feed box.

[0008] The granulator is a rotary drum granulator; a phosphate ammonium pump is provided between the phosphate ammonium outlet of the pre-neutralization tank and the inlet of the phosphate ammonium solution distributor; a dry material elevator is provided between the dryer and the grading screen, and the dry material elevator is used to transport the material discharged from the dryer to the grading screen.

[0009] A return conveyor and a return elevator are provided between the crusher and the granulator. The material outlet of the crusher is connected to the material inlet of the return conveyor, the material outlet of the return conveyor is connected to the material inlet of the return elevator, and the material outlet of the return elevator is connected to the material inlet of the granulator.

[0010] The production method of urea ammonium phosphate fertilizer of the present invention adopts the following technical scheme: it is carried out by adopting the production system of urea ammonium phosphate fertilizer mentioned above, which comprises the following steps: (1) raw material feeding and phosphoric acid neutralization section: urea solution from the boundary zone enters the urea solution distributor, CO(NH2)2 mass concentration in the urea solution is greater than 85%, phosphoric acid from the boundary zone enters the pre-neutralization tank, P2O5 mass concentration in the phosphoric acid is greater than 25%, part of ammonia from the boundary zone enters the pre-neutralization tank, and the other part enters the ammonia distributor; phosphoric acid and ammonia are neutralized in the pre-neutralization tank to generate ammonium phosphate, the molar ratio of ammonia to phosphoric acid is less than 15:10, and the ammonium phosphate solution enters the ammonium phosphate solution distributor from the pre-neutralization tank; (2) urea ammonium phosphate preparation and granulation drying section: in the granulator, urea solution is sprayed on the material layer from the urea solution distributor, and ammonium phosphate solution is sprayed on the material layer from the ammonium phosphate solution distributor, and ammonia enters the material layer from the ammonia distributor to further ammoniation and neutralize the ammonium phosphate in the material layer, and ammonia and phosphorus are further mixed. The molar ratio of acid is finally controlled at 185~195:100; with the help of the rolling of the granulator drum, the material in the granulator is agglomerated into granules. After granulation, the granular material is discharged from the material outlet of the granulator and enters the dryer. After drying in the dryer, the granular material enters the grading screen; (3) Urea phosphate ammonium screening and cooling section: the dry material particles from the dryer are classified in the grading screen, and the coarse particles of dry material with a particle size greater than 4mm are discharged from the coarse particle outlet and enter the crusher for crushing. The crushed dry material enters the granulator from the material inlet of the granulator as return material; the fine powder of dry material with a particle size less than 2mm is discharged from the fine particle outlet and enters the granulator from the material inlet of the granulator as return material; the qualified particles of dry material with a particle size of 2mm-4mm enter the cooler, are cooled in the cooler, and are discharged from the material outlet of the cooler as the target product - urea phosphate ammonium after cooling. The ratio of return material to target product is 2~6:1, and the N / P2O5 mass ratio in the target product is greater than 10:25.

[0011] Hot air with a temperature of 150℃~200℃ enters the dryer from the hot air inlet and dries the granular material in the same flow. The drying time is 15~35min. After drying, the exhaust gas is discharged from the first exhaust gas outlet. The temperature of the dried material is 85℃~95℃, and the water content by mass is less than 1%.

[0012] The temperature of the urea solution entering the urea solution distributor is less than 100°C, the temperature inside the granulator is 65°C~75°C, and the material in the cooler is cooled to 30°C~35°C before being discharged.

[0013] The phosphate ammonium pump is used to deliver the phosphate ammonium in the pre-neutralization tank to the phosphate ammonium sprayer, and the dry material elevator is used to deliver the material discharged from the dryer to the grading screen; the return material is delivered by the return conveyor, and then the return material elevator is used to lift the return material to the material inlet of the granulator.

[0014] The urea granules from the boundary area enter the granulator through the return material conveyor and the return material elevator; the urea solution and urea granules are added in any proportion.

[0015] The beneficial effects of the present invention are as follows: the present invention utilizes wet-process phosphoric acid to be pre-neutralized with ammonia in a pre-neutralization tank, and then the ammonium phosphate slurry is sprayed on the material in the granulator for granulation; an ammonia distributor is embedded in the material to further ammoniate and neutralize the ammonium phosphate in the material, and a urea solution is sprayed on the material in the granulator; the urea ammonium phosphate after granulation is first dried, then screened, and then cooled, and the qualified material is used as the target product - urea ammonium phosphate fertilizer to remove the boundary zone. The use of a pre-neutralization tank has good buffering properties, is easy to operate and control, and has stable product quality; ammonia can be liquid ammonia or gaseous ammonia, and an ammonia distributor is embedded in the granulator material to achieve secondary ammonia neutralization of the ammonium phosphate, increase the diammonium phosphate content in the ammonium phosphate, and improve the N / P2O5 ratio of the target product urea ammonium phosphate, meet the requirements of crop fertilization, and improve the effect of chemical fertilizer application.

[0016] Preferably, the material temperature in the granulator is controlled at ≤75°C, the dryer adopts downstream drying, the hot air temperature is controlled at ≤200°C, the tail gas temperature is controlled at ≤110°C, and the material temperature in the dryer is controlled at ≤95°C, so that the urea will not be hydrolyzed or generate biuret and other adverse situations will occur.

[0017] Preferably, the urea can be a solution or granules; the urea granules are added to the return material conveyor and discharged twice through the return material conveyor and the return material elevator, which is conducive to the uniform distribution of the urea granules. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of a production system of urea ammonium phosphate fertilizer according to an embodiment of the present invention; Figure 2 yes Figure 1 Schematic diagram of the dryer; Figure 3 yes Figure 1 Schematic diagram of the intercooler; Figure 4 It is a performance evaluation table of an application example of the present invention.

[0019] In the figure: 1-pre-neutralization tank, 2-ammonium phosphate pump, 3-return material elevator, 4-granulator, 4.1-urea solution distributor, 4.2-ammonium phosphate solution distributor, 4.3-ammonia distributor, 5-dryer, 5.1-drying drum, 5.2-first feed box, 5.3-first discharge box, 6-dry material elevator, 7-grading screen, 7.1-coarse particle outlet, 7.2-qualified particle outlet, 7.3-fine particle outlet, 8-cooler, 8.1-cooling drum, 8.2-second feed box, 8.3-second discharge box, 9-finished product conveyor, 10-crusher, 11-return material conveyor. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of this patent will be clearly and completely described below in conjunction with the drawings in the embodiments of this patent. Obviously, the described embodiments are part of the embodiments of this patent, not all of the embodiments. The components of the embodiments of this patent generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this patent provided in the drawings is not intended to limit the scope of the patent claimed for protection, but merely represents selected embodiments of this patent. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this patent.

[0021] like Figure 1 As shown, a production system of urea ammonium phosphate fertilizer according to an embodiment of the present invention comprises a pre-neutralization tank 1, a granulator 4, a dryer 5, a grading screen 7, a crusher 10 and a cooler 8, wherein the upper portion of the pre-neutralization tank 1 is provided with a phosphoric acid inlet and an ammonia inlet, the bottom portion of the pre-neutralization tank 1 is provided with a phosphate ammonium outlet, the phosphate ammonium outlet is connected to a phosphate ammonium solution distributor 4.2 which is fed into the granulator 4, and the granulator 4 is provided with a urea solution distributor 4.1 and an ammonia distributor 4.3 at upper and lower positions of the phosphate ammonium solution distributor 4.2, respectively. The material outlet of the granulator 4 is connected to the dryer 5, and the urea solution distributor 4.1 and the ammonia distributor 4.3 are connected to the dryer 5, and the ... urea solution distributor 4.1 and the ammonia distributor 4.3 are connected to the dryer 5, and the urea solution distributor 4.1 and the ammonia distributor 4.3 are connected to the urea solution distributor 4.1. The material inlet of the dryer 5 is connected, the material outlet of the dryer 5 is connected to the material inlet of the grading screen 7, the grading screen 7 has two-stage screens, and the grading screen 7 is provided with a coarse particle outlet 7.1, a qualified particle outlet 7.2 and a fine particle outlet 7.3 from top to bottom. The coarse particle outlet 7.1 is connected to the material inlet of the crusher 10, the fine particle outlet 7.3 and the material outlet of the crusher 10 are connected to the material inlet of the granulator 5, and the qualified particle outlet 7.2 is connected to the material inlet of the cooler 8. The product discharged from the material outlet of the cooler 8 is the target product urea phosphate ammonium.

[0022] The structure of the dryer 5 is as follows Figure 2 As shown, the dryer 5 is a horizontal rotary cylinder structure, which includes a drying drum 5.1. The inner wall of the drying drum 5.1 is provided with a first material scraping plate. The two ends of the drying drum 5.1 are respectively provided with a first feed box 5.2 and a first discharge box 5.3. The material inlet of the dryer 5 is located at the top of the first feed box 5.2, and the material outlet of the dryer 5 is located at the bottom of the first discharge box 5.3. The first feed box 5.2 is provided with a hot air inlet, and the first discharge box 5.3 is provided with a first exhaust gas outlet.

[0023] The cooler 8 is a drum cooler comprising a horizontally arranged cooling drum 8.1. A second material scraping plate is provided on the inner wall of the cooling drum. A second feed box 8.2 and a second discharge box 8.3 are provided at both ends of the cooling drum 8.1. The material inlet of the cooler 8 is provided at the top of the second feed box 8.1, and the material outlet of the cooler 8 is provided at the bottom of the second discharge box 8.3. A cold air inlet is provided on the second discharge box 8.3, and a second exhaust gas outlet is provided on the second feed box 8.2.

[0024] The granulator 4 is a rotary drum granulator; an ammonium phosphate pump 2 is provided between the ammonium phosphate outlet of the pre-neutralization tank 1 and the inlet of the ammonium phosphate solution distributor 4.2; a dry material elevator 6 is provided between the dryer 5 and the grading screen 7, and the material discharged from the dryer 5 is conveyed to the grading screen 7 by the dry material elevator 6. A return conveyor 11 and a return elevator 3 are provided between the crusher 10 and the granulator 4. The material outlet of the crusher 10 is connected to the material inlet of the return conveyor 11, and the material outlet of the return conveyor 11 is connected to the material inlet of the return elevator 3, and the material outlet of the return elevator 3 is connected to the material inlet of the granulator 4.

[0025] A method for producing urea ammonium phosphate fertilizer according to an embodiment of the present invention is carried out using the above-mentioned production system of urea ammonium phosphate fertilizer, and comprises the following steps: (1) Raw material feeding and phosphoric acid neutralization section: Urea solution from the boundary zone enters urea solution distributor 4.1. The temperature of the urea solution entering urea solution distributor 4.1 is less than 100°C (usually 85°C~100°C). The mass concentration of CO(NH2)2 in the urea solution is greater than 85% (usually 85%~98%). Phosphoric acid from the boundary zone enters pre-neutralization tank 1. The mass concentration of P2O5 in phosphoric acid is greater than 25% (usually 25%~55%). Part of ammonia from the boundary zone enters pre-neutralization tank 1 and the other part enters ammonia distributor 4.3. In pre-neutralization tank 1, phosphoric acid and ammonia react to generate ammonium phosphate. The molar ratio of ammonia to phosphoric acid is less than 15:10 (usually 10~15:10). Ammonium phosphate solution enters ammonium phosphate solution distributor 4.2 from pre-neutralization tank 1. Ammonium phosphate in pre-neutralization tank 1 is delivered to ammonium phosphate sprayer by ammonium phosphate pump 2.

[0026] (2) Urea and phosphate ammonium preparation and granulation drying process: In the granulator 4, urea solution is sprayed on the material layer from the urea solution distributor 4.1, and phosphate ammonium solution is sprayed on the material layer from the phosphate ammonium solution distributor 4.2. Ammonia enters the material layer from the ammonia distributor 4.3 to further ammoniate and neutralize the phosphate ammonium in the material layer, and the molar ratio of ammonia to phosphoric acid is finally controlled to be less than 195:100 (usually 185~195:100); the temperature in the granulator 4 is below 75°C (65°C~75°C), and with the help of the rolling of the granulator 4 drum, the material in the granulator 4 is agglomerated into granules. After granulation is completed, the granular material is discharged from the material outlet of the granulator 4 and enters the dryer 5. Hot air with a temperature of less than 200°C (usually 150°C~200°C) enters the dryer 5 from the hot air inlet of the dryer 5 and is dried downstream with the granular material. The drying time is less than 35 minutes. After drying, the exhaust gas is discharged from the first exhaust outlet at a temperature of less than 110°C (usually 100°C to 110°C). The dried material temperature is below 95°C (usually 85°C to 95°C), with a moisture content of less than 1%. After drying in the dryer 5, the granular material enters the grading screen 7.

[0027] (3) Urea phosphate ammonium screening and cooling section: The material discharged from the dryer 5 is transported to the grading screen 7 by the dry material elevator 6; the dry material particles from the dryer 5 are classified in the grading screen 7, and the coarse dry material particles with a particle size greater than 4 mm are discharged from the coarse particle outlet 7.1 and enter the crusher 10 for crushing. The crushed dry material enters the granulator 4 from the material inlet of the granulator 4 as return material; the dry material fine powder with a particle size less than 2 mm is discharged from the fine particle outlet 7.3 and enters the granulator 4 from the material inlet of the granulator 4 as return material; the qualified dry material particles with a particle size of 2 mm-4 mm enter the cooler 8 and are cooled in the cooler 8. After cooling to the set temperature (less than 35 ° C, usually 30 ° C ~ 35 ° C), they are discharged from the material outlet of the cooler 8 as the target product - urea phosphate ammonium. The ratio of the return material to the target product is less than 6:1 (usually 2~6:1), and the N / P2O5 mass ratio in the target product is greater than 10:25.

[0028] When returning the material, the return material is first conveyed by the return material conveyor 11, and then the return material elevator 3 is used to lift the return material to the material inlet of the granulator 4. The urea granules from the boundary area enter the granulator 4 through the return material conveyor 11 and the return material elevator 3; the urea solution and urea granules are added in any proportion.

[0029] In a specific application example, the urea solution containing 95% CO(NH2)2 by mass concentration and 95°C from the boundary area enters the urea solution distributor 4.1, the urea granules from the boundary area enter the discharge end of the return conveyor 11, the wet-process phosphoric acid (containing 40% P2O5 by mass concentration) from the boundary area enters the pre-neutralization tank 1, and part of the ammonia from the boundary area enters the pre-neutralization tank 1 and the other part enters the ammonia distributor 4.3; the return material from the urea ammonium phosphate screening and cooling section and the urea granules from the boundary area are conveyed to the return conveyor 11 and the return conveyor 11. The material is fed into the granulator 4 via the material elevator 3; the mass ratio of urea solution to urea granules is 3:7; in the pre-neutralization tank 1, phosphoric acid and ammonia react to form ammonium phosphate, and the molar ratio of ammonia to phosphoric acid is controlled at 14:10. The ammonium phosphate solution enters the ammonium phosphate solution distributor 4.2 from the side outlet of the pre-neutralization tank 1; in the granulator 4, the urea solution and ammonium phosphate solution are sprayed on the material layer, and ammonia enters the material layer to further ammoniate and neutralize the ammonium phosphate in the material layer, and the molar ratio of ammonia to phosphoric acid is finally controlled at 19:10; with the help of the rolling drum of the granulator 4, the urea solution and ammonium phosphate solution are fed into the granulator 4 via the material elevator 3; the mass ratio of urea solution to urea granules is 3:7; in the pre-neutralization tank 1, phosphoric acid and ammonium phosphate are neutralized, and the molar ratio of ammonia to phosphoric acid is finally controlled at 19:10; with the help of the rolling drum of the granulator 4, the ammonium phosphate solution is fed into the granulator 4 via the material elevator 3; ... The material in the granulator 4 is agglomerated into granules. The temperature in the granulator 4 is 70℃. After granulation, the granular material enters the dryer 5. The hot air with a temperature of 180℃ enters the dryer 5 and dries the granular material in the same flow. The drying time is 25 minutes. After drying, the tail gas with a temperature of 105℃ is discharged to the boundary area. The dried dry material (temperature of 90℃, water content of 0.8%) passes through the dry material elevator 6 and enters the grading screen 7. The dry material particles are classified in the grading screen 7. The coarse dry material particles (particle size > 4mm) enter the crushing The crushing is carried out in the machine 10, and the crushed dry material is fed into the feed end of the return material conveyor 11 as return material; the dry material fine powder (particle size < 2mm) is fed into the feed end of the return material conveyor 11 as return material; the qualified dry material particles (4mm≥particle size≥2mm) enter the cooler 8, where they are cooled and cooled to the set temperature (temperature 30℃) as the target product - urea ammonium phosphate, and finally transported to the boundary area by the finished product conveyor 9; the ratio of return material to target product is 3:1, and the mass ratio of N / P2O5 in the target product is 1:1. The results of the operation using the above example are as follows Figure 4 As shown in the table.

[0030] The present invention produces urea ammonium phosphate using wet-process phosphoric acid, ammonia, and urea. This overcomes the problem of existing ammonium phosphate fertilizers having a too-low N / P2O5 ratio, which does not meet crop fertilization requirements. This reduces fertilization workload, increases crop yields, and improves the effectiveness of chemical fertilizer application. The target product, urea ammonium phosphate, produced using the present invention has a higher N / P2O5 ratio than ammonium phosphate, and this ratio can be adjusted according to crop needs.

Claims

1. A production system for urea ammonium phosphate fertilizer, characterized in that: The invention comprises a pre-neutralization tank, a granulator, a dryer, a grading screen, a crusher and a cooler. The upper part of the pre-neutralization tank is provided with a phosphoric acid inlet and an ammonia inlet, the bottom of the pre-neutralization tank is provided with a phosphate ammonium outlet, the phosphate ammonium outlet is connected with a phosphate ammonium solution distributor which is fed into the granulator, and the granulator is provided with a urea solution distributor and an ammonia distributor above and below the phosphate ammonium solution distributor, respectively. The material outlet of the granulator is connected with the material inlet of the dryer, and the material outlet of the dryer is connected with the material inlet of the grading screen. The grading screen has two-stage screens, and the grading screen is provided with a coarse particle outlet, a qualified particle outlet and a fine particle outlet from top to bottom. The coarse particle outlet is connected with the material inlet of the crusher, the fine particle outlet and the material outlet of the crusher are connected with the material inlet of the granulator, and the qualified particle outlet is connected with the material inlet of the cooler. The product discharged from the material outlet of the cooler is the target product urea phosphate ammonium.

2. The production system of urea ammonium phosphate fertilizer according to claim 1, wherein: The dryer is a horizontal rotary cylinder structure, which includes a drying drum, a first material copying plate is provided on the inner wall of the drying drum, a first feed box and a first discharge box are provided at both ends of the drying drum, the material inlet of the dryer is arranged at the top of the first feed box, and the material outlet of the dryer is arranged at the bottom of the first discharge box. A hot air inlet is provided on the first feed box, and a first exhaust gas outlet is provided on the first discharge box.

3. The production system of urea ammonium phosphate fertilizer according to claim 1, wherein: The cooler adopts a drum cooler, which includes a horizontally arranged cooling drum, an inner wall of the cooling drum is provided with a second material copying plate, and two ends of the cooling drum are respectively provided with a second feed box and a second discharge box, the material inlet of the cooler is arranged at the top of the second feed box, and the material outlet of the cooler is arranged at the bottom of the second discharge box, a cold air inlet is provided on the second discharge box, and a second exhaust gas outlet is provided on the second feed box.

4. The production system of urea ammonium phosphate fertilizer according to claim 1, wherein: The granulator is a rotary drum granulator; a phosphate ammonium pump is provided between the phosphate ammonium outlet of the pre-neutralization tank and the inlet of the phosphate ammonium solution distributor; a dry material elevator is provided between the dryer and the grading screen, and the dry material elevator is used to transport the material discharged from the dryer to the grading screen.

5. The production system of urea ammonium phosphate fertilizer according to claim 1, characterized in that: A return conveyor and a return elevator are provided between the crusher and the granulator. The material outlet of the crusher is connected to the material inlet of the return conveyor, the material outlet of the return conveyor is connected to the material inlet of the return elevator, and the material outlet of the return elevator is connected to the material inlet of the granulator.

6. A method for producing urea ammonium phosphate fertilizer, which is carried out using the urea ammonium phosphate fertilizer production system according to any one of claims 1 to 5, characterized in that: It includes the following steps: (1) Raw material feeding and phosphoric acid neutralization section: Urea solution from the boundary area enters the urea solution distributor, and the mass concentration of CO(NH2)2 in the urea solution is greater than 85%. Phosphoric acid from the boundary area enters the pre-neutralization tank, and the mass concentration of P2O5 in the phosphoric acid is greater than 25%. Part of the ammonia from the boundary area enters the pre-neutralization tank and the other part enters the ammonia distributor; in the pre-neutralization tank, phosphoric acid and ammonia react to generate ammonium phosphate, and the molar ratio of ammonia to phosphoric acid is less than 15:

10. The ammonium phosphate solution enters the ammonium phosphate solution distributor from the pre-neutralization tank; (2) Urea and ammonium phosphate preparation and granulation and drying process: In the granulator, urea solution is sprayed from the urea solution distributor onto the material layer, and ammonium phosphate solution is sprayed from the ammonium phosphate solution distributor onto the material layer. Ammonia enters the material layer from the ammonia distributor to further ammoniate and neutralize the ammonium phosphate in the material layer. The molar ratio of ammonia to phosphoric acid is finally controlled at 185~195:

100. With the help of the rolling of the granulator drum, the material in the granulator is agglomerated into granules. After granulation, the granular material is discharged from the material outlet of the granulator into the dryer. After drying in the dryer, the granular material enters the grading screen. (3) Urea phosphate ammonium screening and cooling section: The dry material particles from the dryer are classified in the grading screen, and the coarse particles of dry material with a particle size greater than 4 mm are discharged from the coarse particle outlet and enter the crusher for crushing. The crushed dry material enters the granulator from the material inlet of the granulator as return material; the fine powder of dry material with a particle size less than 2 mm is discharged from the fine particle outlet and enters the granulator from the material inlet of the granulator as return material; the qualified particles of dry material with a particle size of 2 mm-4 mm enter the cooler and are cooled in the cooler. After cooling, they are discharged from the material outlet of the cooler as the target product - urea phosphate ammonium. The ratio of return material to target product is 2~6:1, and the mass ratio of N / P2O5 in the target product is greater than 10:

25.

7. The production method of urea ammonium phosphate fertilizer according to claim 6, wherein: Hot air with a temperature of 150℃~200℃ enters the dryer from the hot air inlet and dries the granular material in the same flow. The drying time is 15~35min. After drying, the exhaust gas is discharged from the first exhaust gas outlet. The temperature of the dried material is 85℃~95℃, and the water content by mass is less than 1%.

8. The production method of urea ammonium phosphate fertilizer according to claim 6, wherein: The temperature of the urea solution entering the urea solution distributor is less than 100°C, the temperature inside the granulator is 65°C~75°C, and the material in the cooler is cooled to 30°C~35°C before being discharged.

9. The production method of urea ammonium phosphate fertilizer according to claim 6, wherein: The phosphate ammonium pump is used to deliver the phosphate ammonium in the pre-neutralization tank to the phosphate ammonium sprayer, and the dry material elevator is used to deliver the material discharged from the dryer to the grading screen; the return material is delivered by the return conveyor, and then the return material elevator is used to lift the return material to the material inlet of the granulator.

10. The method for producing urea ammonium phosphate fertilizer according to claim 9, wherein: The urea granules from the boundary area enter the granulator through the return material conveyor and the return material elevator; the urea solution and urea granules are added in any proportion.

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