Production system and method of sulfur polyammonium phosphate fertilizer

Abstract

The invention discloses a production system and method of a sulfur polyammonium phosphate fertilizer, the production system of the sulfur polyammonium phosphate fertilizer comprises a cross tube reactor, a granulator, a cooler, a grading screen and a crusher, sulfuric acid and phosphoric acid respectively enter two opposite branch tubes of the cross tube reactor at the same time, and after the sulfuric acid and the phosphoric acid are fully mixed, the mixture is discharged into the cross tube reactor; the mixed acid reacts with ammonia from an ammonia branch pipe to generate ammonium polysulfate phosphate slurry, then the slurry is sprayed on the material in the granulator for granulation, the granulated ammonium polysulfate phosphate is cooled and then screened, and the qualified material is used as a target product. The cross tube reactor is used for neutralization reaction, the equipment is compact, the reaction is violent, the evaporated moisture is much, and subsequent drying is not needed. The problems that the ratio of N / P2O5 of a monoammonium phosphate fertilizer is too small, monoammonium phosphate or diammonium phosphate does not contain sulfur and ammonium polyphosphate, and the fertilizer does not meet the fertilizer application requirements of crops are solved, the fertilizer application workload is reduced, the crop yield is increased, and the fertilizer application effect is improved.

Description

Technical Field

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

[0002] Plant growth and development require five essential conditions: light, heat, air, water, and nutrients. Nutrients required for plant growth are primarily supplied through soil and fertilizer. Essential plant nutrients have three physiological characteristics: (1) they have a direct effect on plant growth or physiological metabolism; (2) if any one of these elements is lacking, the plant cannot grow and develop normally; and (3) their physiological functions cannot be replaced by other elements.

[0003] Sixteen essential nutrients are defined as essential for plant growth, including nitrogen (N), phosphorus (P), and sulfur (S). Crops contain greater than 2% nitrogen (N) by weight, greater than 0.4% phosphorus (P) by weight, and a sulfur (S) mass percentage comparable to that of phosphorus (P). Nitrogen is a component of many organic compounds in plants, including proteins (16%-18% nitrogen), nucleic acids (16%-18% nitrogen), chlorophyll, enzymes, vitamins, alkaloids, and hormones. Phosphorus is second only to nitrogen in the amount of nutrients in crop seeds. Phosphorus also contributes to drought, cold, and disease resistance, and early maturity. Sulfur, present in plants at a similar level to phosphorus, is a component of important compounds such as proteins, enzymes, and vitamin B1, making it second only to nitrogen and phosphorus in importance. Cruciferous crops contain high levels of sulfur, with rapeseed, for example, containing up to 0.89%.

[0004] The low amounts of available nitrogen (N), phosphorus (P), and sulfur (S) 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 production technology is mature, and its nutrient content is high, allowing for direct fertilizer use. However, the N / P2O5 ratio of MAP is too low, at approximately 1:5 by mass. Neither MAP nor DAP contains sulfur, making them insufficient for crop production. Plants require a variety of nutrients for growth and development, but yield is determined by the nutrient with the lowest relative abundance in the soil relative to plant needs. This nutrient is the limiting factor for plant production. Without supplementation, even adding other nutrients will struggle to increase yield, reducing the economic benefits of fertilization. For example, in nitrogen-deficient soils, applying phosphorus fertilizer will be difficult to achieve yield gains, and the same applies to other nutrients. Therefore, it is necessary to improve the existing ammonium phosphate production system and urgently need to provide a process for producing a new type of sulfur-polyammonium phosphate fertilizer containing nitrogen, phosphorus, sulfur, and a large N / P2O5 ratio that can better meet the needs of crops. Summary of the Invention

[0005] The object of the present invention is to provide a system and method for producing polyammonium phosphate sulfate fertilizer, aiming to produce polyammonium phosphate sulfate using sulfuric acid, wet-process phosphoric acid and ammonia, thereby overcoming the technical problems that the N / P2O5 ratio of monoammonium phosphate fertilizer is too small, and neither monoammonium phosphate nor diammonium phosphate contains sulfur element and polyammonium phosphate, which does not meet the requirements for crop fertilization.

[0006] The production system of ammonium phosphate polysulfide fertilizer of the present invention adopts the following technical scheme: a production system of ammonium phosphate polysulfide fertilizer, which includes a cross-tube reactor, a granulator, a cooler, a grading screen and a crusher arranged in sequence, wherein the cross-tube reactor includes a tubular body, the two ends of the tubular body are respectively an inlet and an outlet, a sulfuric acid branch pipe and a phosphoric acid branch pipe are provided on the side of the tubular body near the inlet, the sulfuric acid branch pipe and the phosphoric acid branch pipe are symmetrically arranged on both sides of the tubular body, an ammonia branch pipe is provided in the inlet end of the tubular body, the ammonia branch pipe is inserted into the tubular body and the outlet end exceeds the sulfuric acid branch pipe and the phosphoric acid branch pipe. Acid branch pipe, the outlet of the tubular body is located in the granulator, and a downwardly arranged sprayer is provided at the outlet of the tubular body; the material outlet of the granulator is connected with the material inlet of the cooler, the material outlet of the cooler is connected with the material inlet of the grading screen, 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 material discharged from the qualified particle outlet is the finished product of polyurethane sulfate, the fine particle outlet is connected with the material inlet of the granulator, the coarse particle outlet is connected with the material inlet of the crusher, and the material outlet of the crusher is connected with the material inlet of the grading screen.

[0007] The qualified particle outlet is connected to a finished product conveyor.

[0008] The fine particle outlet is connected to a return material conveyor, the outlet of the return material conveyor is connected to a return material elevator, and the outlet of the return material elevator is communicated with the material inlet of the granulator.

[0009] The cooler adopts a drum cooler, which includes a horizontally arranged drum, an inner wall of the drum is provided with a material copying plate, two ends of the drum are respectively provided with a feed box and a discharge box, the material inlet of the cooler is arranged at the top of the feed box, the material outlet of the cooler is arranged at the bottom of the discharge box, a cold air inlet is provided on the discharge box, and an exhaust gas outlet is provided on the feed box.

[0010] The position of the feed box is higher than that of the discharge box, and the roller is tilted downward from the feed box to the discharge box.

[0011] The production method of ammonium phosphate sulfate fertilizer of the present invention adopts the following technical scheme: a production method of ammonium phosphate sulfate fertilizer, which is carried out by adopting the production system of ammonium phosphate sulfate fertilizer, and comprises the following steps: (1) feeding and slurry preparation section of cross-tube reactor: ammonia from the boundary area enters the ammonia branch pipe, sulfuric acid from the boundary area enters the sulfuric acid branch pipe, and phosphoric acid from the boundary area enters the phosphoric acid branch pipe; sulfuric acid and phosphoric acid are fully mixed in the space inside the cross-tube reactor and outside the ammonia branch pipe, and the uniformly mixed mixed acid reacts with ammonia coming out of the outlet of the ammonia branch pipe to generate ammonium phosphate sulfate slurry, and the slurry after the reaction is completed is discharged from the outlet of the tubular body of the cross-tube reactor and enters the granulator; (2) feeding and granulation section of granulator: the ammonium phosphate sulfate slurry from the cross-tube reactor is sprayed on the granulator. On the material layer in the granulator, the material is agglomerated into granules in the granulator. After granulation, the granular material enters the material inlet of the cooler from the material outlet of the granulator; (3) Cooling and screening section: the granular polyphosphate ammonium sulfate from the granulator is cooled in the cooler, and is discharged from the outlet at the bottom of the cooler after cooling, and then enters the grading screen. The granular material particles are classified in the grading screen. Granular materials with a particle size of 2-4mm are qualified particles, and are discharged from the grading screen from the qualified particle outlet as the target product - polyphosphate ammonium sulfate granular material; coarse particles with a particle size greater than 4mm are discharged from the coarse particle outlet and the grading screen, and then enter the crusher for crushing, and then enter the grading screen for classification again; fine powder of granular materials with a particle size less than 2mm is discharged from the grading screen from the fine particle outlet and enters the material inlet of the granulator as return material.

[0012] The mass concentration of H2SO4 in the sulfuric acid entering the sulfuric acid branch pipe is greater than 85%, the mass concentration of P2O5 in the phosphoric acid entering the phosphoric acid branch pipe is greater than 40%, the mass ratio of the two acids is H2SO4:H3PO4≥25:144, the reaction temperature in the cross-tube reactor is greater than 200°C, the molar number of ammonia in the granulator is: (2 times the molar number of sulfuric acid + the molar number of phosphoric acid) = 1:1, the temperature in the granulator is greater than 70°C, and the mass percentage of water in the granular material discharged from the granulator material outlet is less than 2%.

[0013] The granular material is cooled by cold air in the cooler and discharged after being cooled to below 45°C in the cooler.

[0014] The target product contains less than 1% by mass of H2O, more than 4% by mass of S, more than 13.5% by mass of N, more than 30.7% by mass of P2O5, a mass ratio of N / P2O5 greater than 1:5, and P2O5 in ammonium polyphosphate accounts for more than 8% of the total P2O5; the ratio of return material to target product is less than 6.

[0015] Use the finished product conveyor to transport the qualified particles discharged from the qualified particle outlet; use the crushed material elevator to send the coarse particles discharged from the coarse particle outlet to the crusher; use the return material conveyor and return material elevator to return the granular material fine powder discharged from the fine particle outlet to the granulator.

[0016] The beneficial effects of the present invention are as follows: first, a cross-tube reactor is adopted, sulfuric acid and phosphoric acid are mixed at the front of the cross-tube reactor to form a mixed acid, and the mixed acid and ammonia are neutralized at the rear of the tubular reactor. The equipment is compact, occupies a small space, and the production is continuous, and the entire process is completed in one go; the cross-tube reactor has a short reaction time, a violent reaction, a high temperature rise, a high pressure, and a large amount of evaporated water, so that polyphosphate is easily generated and more water is evaporated. Therefore, the water content of the ammonium polyphosphate sulfate particles discharged from the granulator is very low (water content by mass concentration is ≤2%), and no drying machine is required for drying, thereby saving energy and reducing dust and tail gas; and the granular materials discharged from the granulator are cooled and then classified in a grading screen to screen out the target product.

[0017] P2O5 accounts for 8% to 25% of the total P2O5 in ammonium polyphosphate. Ammonium polyphosphate has a chelating effect on metal ions and is therefore not easily fixed by metal ions such as iron and calcium in the soil. Instead, it can form soluble complexes with ineffective trace elements in the soil and be absorbed by plants. Polyphosphate is not directly absorbed by plants, but is gradually hydrolyzed into orthophosphoric acid in the soil and utilized by plants. Therefore, it is a slow-soluble and long-lasting fertilizer. The target product, ammonium sulfate polyphosphate, contains 4% to 12% sulfur (S), which can be adjusted according to crop needs. Sulfur is also a nutrient required by crops, and ammonium sulfate polyphosphate is particularly suitable for sulfur-deficient soils. Ammonium sulfate polyphosphate does not easily absorb moisture or clump, and has good physical properties. The target product, ammonium sulfate polyphosphate, has a N / P2O5 mass ratio greater than that of monoammonium phosphate, which is 1:5. It can be adjusted according to crop needs, with an N / P2O5 mass ratio ranging from 1:3.8 to 1:1.9.

[0018] The present invention uses sulfuric acid, wet-process phosphoric acid and ammonia to produce sulfur-polyammonium phosphate, thereby overcoming the problems that the N / P2O5 ratio of monoammonium phosphate fertilizer is too small, and neither monoammonium phosphate nor diammonium phosphate contains sulfur element and polyammonium phosphate, which does not meet the requirements for crop fertilization. The present invention reduces the workload of fertilization, increases crop yields, improves the effect of chemical fertilizer application, and can better meet the needs of crops. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A system schematic diagram of an embodiment of a production system of polyammonium phosphate sulfate fertilizer according to the present invention; Figure 2 for Figure 1 Schematic diagram of the cross-tube reactor; Figure 3 yes Figure 1 Schematic diagram of the intercooler; Figure 4 The present invention is a specific application example of a 30 ton / hour ammonium sulfate polyphosphate fertilizer device performance evaluation results table.

[0020] Among them: 1- cross tube reactor, 1.1- tubular body, 1.2- ammonia branch pipe, 1.3- sulfuric acid branch pipe, 1.4- phosphoric acid branch pipe, 2- granulator, 3- cooler, 3.1- drum, 3.2- feed box, 3.3- discharge box, 4- grading screen, 4.1- coarse particle outlet, 4.2- qualified particle outlet, 4.3- fine particle outlet, 5- finished product conveyor, 6- crusher, 7- crushed material elevator, 8- return material conveyor, 9- return material elevator. DETAILED DESCRIPTION

[0021] 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 here 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 the selected embodiments of this patent. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this patent. The embodiments of this patent are described in detail below, and examples of the embodiments are shown in the drawings, where the same or similar numbers throughout represent the same or similar elements or elements with the same or similar functions.

[0022] like Figure 1 As shown, the production system of polyammonium sulfate fertilizer according to one embodiment of the present invention comprises a cross-tube reactor 1, a granulator 2, a cooler 3, a grading screen 4 and a crusher 6 arranged in sequence, as shown in FIG. Figure 2As shown, the cross-tube reactor 1 includes a tubular body 1.1, with an inlet and an outlet at both ends of the tubular body 1.1 respectively. A sulfuric acid branch pipe 1.3 and a phosphoric acid branch pipe 1.4 are provided on the side near the inlet of the tubular body 1.1. The sulfuric acid branch pipe 1.3 and the phosphoric acid branch pipe 1.4 are symmetrically arranged on both sides of the tubular body 1. An ammonia branch pipe 1.2 is provided in the inlet end of the tubular body 1. The ammonia branch pipe 1.2 is inserted into the tubular body 1.1 and the outlet end exceeds the sulfuric acid branch pipe 1.3 and the phosphoric acid branch pipe 1.4. The outlet of the tubular body 1.1 is located in the granulator 2, and a downwardly arranged sprayer is provided at the outlet of the tubular body 1.1; the granulator 2 adopts a rotary drum granulator, and the material outlet of the granulator 2 is connected to the material inlet of the cooler 3. The material outlet of cooler 3 is connected to the material inlet of grading screen 4. Grading screen 4 is provided with a coarse particle outlet 4.1, a qualified particle outlet 4.2, and a fine particle outlet 4.3, from top to bottom. Grading screen 4 has two screens: coarse particle outlet 4.1 and qualified particle outlet 4.2 are both located on the side of grading screen 4. Coarse particle outlet 4.1 is located above the first screen, qualified particle outlet 4.2 is located between the two screens, and fine particle outlet 4.3 is located below the second screen. The material discharged from qualified particle outlet 4.2 is the finished polyurethane sulfate product. The fine particle outlet 4.3 is connected to the material inlet of granulator 2, the coarse particle outlet 4.1 is connected to the material inlet of crusher 6, and the material outlet of crusher 6 is connected to the material inlet of grading screen 4. The qualified particle outlet 4.2 is connected to a finished product conveyor 5, which transports the target product.

[0023] The fine particle outlet 4.3 is connected to a return material conveyor 8, the outlet of the return material conveyor 8 is connected to a return material elevator 9, the outlet of the return material elevator 9 is connected to the material inlet of the granulator 2, and the return material is delivered to the material inlet of the granulator 2 by the return material conveyor 8 and the return material elevator 9.

[0024] like Figure 3 As shown, the cooler 3 is a drum cooler. The drum cooler 3 includes a horizontal drum 3.1, which rotates via two front and rear rollers and a transmission gear. A shovel is provided on the inner wall of the drum 3.1. A feed box 3.2 and a discharge box 3.3 are located at either end of the drum. The material inlet of the cooler 3 is located at the top of the feed box 3.2, and the material outlet of the cooler 3 is located at the bottom of the discharge box 3.3. The discharge box 3.3 is provided with a cold air inlet and an exhaust gas outlet. The feed box 3.2 is positioned higher than the discharge box 3.3, and the drum 3.1 slopes downward from the feed box 3.2 to the discharge box 3.3.

[0025] A method for producing ammonium polyphosphate sulfate fertilizer according to an embodiment of the present invention is carried out using the above-mentioned ammonium polyphosphate sulfate fertilizer production system, and comprises the following steps: (1) Cross-tube reactor feeding and slurry preparation section: ammonia from the boundary area enters the ammonia branch pipe 1.2, sulfuric acid from the boundary area enters the sulfuric acid branch pipe 1.3, and phosphoric acid from the boundary area enters the phosphoric acid branch pipe 1.4; sulfuric acid and phosphoric acid are fully mixed in the space inside the cross-tube reactor 1 and outside the ammonia branch pipe 1.2, and the evenly mixed mixed acid reacts with the ammonia from the outlet of the ammonia branch pipe 1.2 to form polyphosphate ammonium sulfate slurry. The slurry after the reaction is completed is discharged from the outlet of the tubular body 1.1 of the cross-tube reactor 1 and enters the granulator 2; the mass concentration of H2SO4 in the sulfuric acid entering the sulfuric acid branch pipe 1.3 is greater than 85% (usually contains H2SO4 mass concentration of 85%~98%), and the mass concentration of P2O5 in the phosphoric acid entering the phosphoric acid branch pipe 1.4 is greater than 40% (usually contains P2O5 mass concentration of 40%~55%). The mass ratio of the two acids is H2SO4: H3PO4≥25:144 (usually 100:115~100:576), the reaction temperature in the cross-tube reactor 1 is greater than 200°C (usually 200°C~260°C), and the molar number of ammonia: (2 times the molar number of sulfuric acid + the molar number of phosphoric acid) = 1:1.

[0026] (2) Granulator feeding and granulation section: In granulator 2, the ammonium polyphosphate slurry from the cross-tube reactor 1 is sprayed on the material layer in granulator 2. The temperature in granulator 2 is greater than 70°C (usually 70°C~120°C). The material is agglomerated into granules in granulator 2. After granulation, the granular material enters the material inlet of cooler 3 from the material outlet of granulator 2. The water content of the granular material discharged from the outlet of granulator 2 is less than 2% by mass. (3) Cooling and screening process: The granular polyphosphate ammonium sulfide from the granulator 2 is cooled in the cooler 3, and after cooling to below 45°C (the temperature is usually 30°C~45°C), it is discharged from the outlet at the bottom of the cooler 3 and then enters the grading screen 4. The granular material particles are classified in the grading screen 4. Granular materials with a particle size of 2-4 mm are qualified particles, and are discharged from the grading screen from the qualified particle outlet 4.2 as the target product - polyphosphate ammonium sulfide granular material; coarse particles with a particle size greater than 4 mm are discharged from the grading screen 4 from the coarse particle outlet 4.1, and then enter the crusher 6 for crushing, and then enter the grading screen 4 for classification again; the qualified particles discharged from the qualified particle outlet 4.2 are transported by the finished product conveyor 5; the coarse particles discharged from the coarse particle outlet 4.1 are sent to the crusher 6 by the crushed material elevator 7; the fine powder of the granular material discharged from the fine particle outlet 4.3 is returned to the granulator 2 by the return conveyor 8 and the return elevator 9. The granular material fine powder with a particle size of less than 2 mm passes through the grading screen 4 from the fine particle outlet 4.3 and enters the material inlet of the granulator 2 as return material.

[0027] The target product contains less than 1% H2O by mass, more than 4% S by mass (usually 4% to 12%), more than 13.5% N by mass (usually 13.5% to 16.5%), more than 30.7% P2O5 by mass (usually 30.7% to 51%), an N / P2O5 mass ratio greater than 1:5 (can be adjusted according to crop needs, the N / P2O5 mass ratio range is 1:3.8 to 1:1.9), and P2O5 in ammonium polyphosphate accounts for more than 8% of the total P2O5 (usually 8% to 25%); the ratio of return material to target product is less than 6 (usually 1 to 6).

[0028] In a specific application example of the present invention, the sulfuric acid entering the sulfuric acid branch 1.3 of the cross-tube reactor 1 has an H2SO4 concentration of 90% by mass, and the phosphoric acid entering the phosphoric acid branch 1.4 has a P2O5 concentration of 52% by mass. The reaction temperature in the cross-tube reactor 1 is controlled at 221°C. The molar ratio of ammonia to (2 times the molar ratio of sulfuric acid + the molar ratio of phosphoric acid) is 1:1, and the mass ratio of the two acids is H2SO4:H3PO4=1:5. The temperature inside the granulator 2 is 118°C, and the granular material exiting the granulator 2 has a water content of 0.9% by mass. The ratio of return material to target product is 2.8, and the target product contains 0.8% by mass of H2O, 4.5% by mass of S, 13.7% by mass of N, and 49.8% by mass of P2O5. The N / P2O5 mass ratio is 1:3.64, and the P2O5 content in the ammonium polyphosphate is 15% of the total P2O5. In this application example, the performance evaluation results of a 30-ton / hour sulfur-ammonium polyphosphate fertilizer unit are as follows: Figure 4 As shown in the table.

Claims

1. A production system for polyammonium phosphate sulfate fertilizer, characterized in that: The invention relates to a method for producing a granulator comprising a cross-tube reactor, a granulator, a cooler, a grading screen and a crusher, wherein the cross-tube reactor comprises a tubular body, wherein the two ends of the tubular body are respectively an inlet and an outlet, a sulfuric acid branch pipe and a phosphoric acid branch pipe are provided on the side of the tubular body near the inlet, the sulfuric acid branch pipe and the phosphoric acid branch pipe are symmetrically arranged on both sides of the tubular body, an ammonia branch pipe is provided in the inlet end of the tubular body, the ammonia branch pipe is inserted into the tubular body and the outlet end exceeds the sulfuric acid branch pipe and the phosphoric acid branch pipe, the outlet of the tubular body is located in the granulator, and a downwardly arranged sprayer is provided at the outlet of the tubular body; the material outlet of the granulator is connected to the material inlet of the cooler, the material outlet of the cooler is connected to the material inlet of the grading screen, the grading screen is sequentially provided with a coarse particle outlet, a qualified particle outlet and a fine particle outlet from top to bottom, the material discharged from the qualified particle outlet is a finished product of polyurethane sulfate, the fine particle outlet is connected to the material inlet of the granulator, the coarse particle outlet is connected to the material inlet of the crusher, and the material outlet of the crusher is connected to the material inlet of the grading screen.

2. The production system of polyammonium phosphate sulfate fertilizer according to claim 1, characterized in that: The qualified particle outlet is connected to a finished product conveyor.

3. The production system of polyammonium phosphate sulfate fertilizer according to claim 1, characterized in that: The fine particle outlet is connected to a return material conveyor, the outlet of the return material conveyor is connected to a return material elevator, and the outlet of the return material elevator is communicated with the material inlet of the granulator.

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

5. The production system of polyammonium phosphate sulfate fertilizer according to claim 4, characterized in that: The position of the feed box is higher than that of the discharge box, and the roller is tilted downward from the feed box to the discharge box.

6. A method for producing polyammonium phosphate sulfate fertilizer, which is carried out using the polyammonium phosphate sulfate fertilizer production system according to any one of claims 1 to 5, characterized in that: It includes the following steps: (1) Feeding and slurry preparation section of the cross-tube reactor: ammonia from the boundary area enters the ammonia branch pipe, sulfuric acid from the boundary area enters the sulfuric acid branch pipe, and phosphoric acid from the boundary area enters the phosphoric acid branch pipe; sulfuric acid and phosphoric acid are fully mixed in the space inside the cross-tube reactor and outside the ammonia branch pipe, and the evenly mixed acid reacts with ammonia from the outlet of the ammonia branch pipe to form polyammonium phosphate sulfate slurry. The slurry after the reaction is completed is discharged from the outlet of the tubular body of the cross-tube reactor and enters the granulator; (2) Granulator feeding and granulation section: In the granulator, the ammonium polyphosphate slurry from the cross-tube reactor is sprayed on the material layer in the granulator, and the material is agglomerated into granules in the granulator. After granulation, the granular material enters the material inlet of the cooler from the material outlet of the granulator; (3) Cooling and screening section: The granular ammonium sulfide phosphate from the granulator is cooled in the cooler and discharged from the outlet at the bottom of the cooler after cooling, and then enters the grading screen. The granular material particles are classified in the grading screen. Granular materials with a particle size of 2-4 mm are qualified particles, and pass through the grading screen from the qualified particle outlet as the target product - ammonium sulfide granular material; coarse particles with a particle size greater than 4 mm are discharged from the coarse particle outlet through the grading screen, and then enter the crusher for crushing, and then enter the grading screen for classification again; fine powder of granular materials with a particle size less than 2 mm is discharged from the fine particle outlet through the grading screen and enters the material inlet of the granulator as return material.

7. The method for producing polyammonium phosphate sulfate fertilizer according to claim 6, wherein: The mass concentration of H2SO4 in the sulfuric acid entering the sulfuric acid branch pipe is greater than 85%, the mass concentration of P2O5 in the phosphoric acid entering the phosphoric acid branch pipe is greater than 40%, the mass ratio of the two acids is H2SO4:H3PO4≥25:144, the reaction temperature in the cross-tube reactor is greater than 200°C, the molar number of ammonia in the granulator is: (2 times the molar number of sulfuric acid + the molar number of phosphoric acid) = 1:1, the temperature in the granulator is greater than 70°C, and the mass percentage of water in the granular material discharged from the granulator material outlet is less than 2%.

8. The method for producing polyammonium phosphate sulfate fertilizer according to claim 6, wherein: The granular material is cooled by cold air in the cooler and discharged after being cooled to below 45°C in the cooler.

9. The method for producing polyammonium phosphate sulfate fertilizer according to claim 6, wherein: The target product contains less than 1% by mass of H2O, more than 4% by mass of S, more than 13.5% by mass of N, more than 30.7% by mass of P2O5, a mass ratio of N / P2O5 greater than 1:5, and P2O5 in ammonium polyphosphate accounts for more than 8% of the total P2O5; the ratio of return material to target product is less than 6.

10. The method for producing polyammonium phosphate sulfate fertilizer according to claim 6, wherein: Use the finished product conveyor to transport the qualified particles discharged from the qualified particle outlet; use the crushed material elevator to send the coarse particles discharged from the coarse particle outlet to the crusher; use the return material conveyor and return material elevator to return the granular material fine powder discharged from the fine particle outlet to the granulator.

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