High-concentration urea-based compound fertilizer production system

Abstract

The utility model belongs to a high-concentration urea-based compound fertilizer production system. Comprising a urea production unit, a urea melt outlet pipeline in the urea production unit is connected with a compound fertilizer stirring tank arranged around the urea production unit, and the bottom of the compound fertilizer stirring tank is connected with the compound fertilizer production unit through a slurry pump and a long-distance conveying pipeline; the device has the characteristics that the steam energy consumption is saved, the production cost is reduced, the content of biuret in the product is reduced on the basis of preventing the urea production unit and the compound fertilizer production unit from arranging the safety distance together, and the product quality is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of compound fertilizer production, and particularly relates to a high-concentration urea-based compound fertilizer production system. Background Art

[0002] In terms of the chemical fertilizer manufacturing method, the compound fertilizer with nitrogen source being urea is called urea-based compound fertilizer. The urea-based compound fertilizer is a high-concentration nitrogen, phosphorus and potassium multi-component compound fertilizer prepared by secondary processing using urea as the nitrogen source and basic fertilizers such as ammonium chloride, potassium chloride, potassium sulfate, and ammonium phosphate as raw materials. The commonly used production methods include extrusion method, granulation method, slurry method and melt method, etc. For high-concentration urea-based compound fertilizers, the slurry method requires melting urea granules with steam; specifically, high-concentration urea-based compound fertilizers generally adopt the process that urea granules are sent to a tower, melted with steam, mixed with other raw materials, and then granulated through a granulation tower; the above process methods have the following defects: (1) Since the urea content of high-concentration urea-based compound fertilizers is high, a large amount of urea is required as raw material, resulting in defects of high steam consumption and high production cost; (2) During the melting process of urea granules, the temperature needs to be strictly controlled to avoid excessive biuret content, which may lead to unqualified products, that is, the product quality risk is relatively high.

[0003] Furthermore, some enterprises have tried to directly introduce the urea melt produced in the urea production system into the compound fertilizer production system for the production of high-concentration urea-based compound fertilizers; however, due to the overly complex equipment in both the urea production system and the compound fertilizer production system, and the large floor area, the urea melt in the urea production system must be transported over a long distance; according to common knowledge, the high concentration of the urea melt and the long transportation distance will inevitably lead to an increase in biuret, which will in turn affect the product quality; that is, currently, the urea melt produced in the urea production system cannot be directly applied to the compound fertilizer production system. Summary of the Utility Model

[0004] In order to make up for the above deficiencies, the utility model provides a high-concentration urea-based compound fertilizer production system to solve the problems existing in the prior art.

[0005] To achieve the above object, the utility model provides the following technical solutions:

[0006] A high-concentration urea-based compound fertilizer production system, which includes a urea production unit. The urea melt outlet pipeline in the urea production unit is connected to a compound fertilizer mixing tank arranged around the urea production unit, and the bottom of the compound fertilizer mixing tank is connected to a compound fertilizer production unit through a slurry pump and a long-distance transportation pipeline.

[0007] The beneficial effects of the present utility model are as follows: The present utility model overcomes the production method of using urea granules for melting to prepare high-concentration urea-based compound fertilizers in traditional technologies. The molten urea liquid in the urea production unit enters the compound fertilizer mixing tank, and other raw materials are added to the compound fertilizer mixing tank to form a slurry. By the properties of the slurry, the purpose of avoiding the generation of high-content biuret is achieved. It has the characteristics of saving steam energy consumption, reducing production costs, reducing the content of biuret in the product on the basis of avoiding the over-large floor area occupied by the layout of the urea production unit and the compound fertilizer production unit together, and ensuring the product quality.

[0008] Preferably, the urea production unit includes a urea secondary evaporation separator. The outlet of the urea secondary evaporation separator is connected to the urea granulation nozzle in the urea granulation tower through a melting pump. A first three-way valve and a first control valve are sequentially arranged on the pipeline between the melting pump and the urea granulation tower; the third end of the first three-way valve is connected to the compound fertilizer mixing tank through a second control valve.

[0009] Preferably, the compound fertilizer production unit at least includes a compound fertilizer granulation tower. The compound fertilizer granulation nozzle in the compound fertilizer granulation tower is connected to the end of a long-distance conveying pipeline through a pipeline.

[0010] Preferably, a temperature sensor is provided at the end of the long-distance conveying pipeline. A second three-way valve is arranged between the long-distance conveying pipeline and the compound fertilizer granulation nozzle. The second end of the second three-way valve is connected to the compound fertilizer granulation nozzle through a third control valve. The third end of the second three-way valve is connected to a stirring and heating tank through a fourth control valve. The outlet of the stirring and heating tank is connected to the compound fertilizer granulation nozzle.

[0011] Preferably, the compound fertilizer mixing tank includes a molten urea liquid inlet provided at the upper part of the compound fertilizer mixing tank, and a slurry outlet provided at the lower part of the compound fertilizer mixing tank and connected to a slurry pump. A first stirring part is arranged inside the compound fertilizer mixing tank, and a first heat exchange coil is arranged inside the compound fertilizer mixing tank; a first screw feeder is provided at the top of the compound fertilizer mixing tank.

[0012] Preferably, the stirring and heating tank includes a slurry inlet provided at the upper part of the stirring and heating tank, and a slurry outlet provided at the lower part of the stirring and heating tank. A second stirring part is arranged inside the stirring and heating tank, a second heat exchange coil is arranged inside the compound fertilizer mixing tank, and a second screw feeder is provided at the top of the stirring and heating tank.

[0013] Preferably, both the first heat exchange coil and the second heat exchange coil are heat exchange coils. The lower inlet of the heat exchange coil is connected to the steam network, and the upper outlet of the heat exchange coil is connected to a condensate storage tank.

[0014] Preferably, both the first stirring part and the second stirring part are stirring parts. The stirring part includes a stirring motor. The main shaft of the stirring motor is connected to a stirring shaft, and stirring blades are arranged on the stirring shaft extending into the tank.

[0015] Preferably, a product conveyor belt is provided at the bottom of the compound fertilizer granulation tower, and a fertilizer vibrating screen is provided at the end of the product conveyor belt. Different outlets of the fertilizer vibrating screen are respectively connected to different particle size packaging systems.

[0016] A high-concentration urea-based compound fertilizer production system made according to the above solution. In order to overcome the defects in the traditional technology, the present utility model saves the relevant equipment for melting urea particles in the compound fertilizer production unit while newly adding a compound fertilizer mixing tank near the urea production unit. The compound fertilizer mixing tank is used to couple the urea production unit and the compound fertilizer production unit, so as to achieve the method of preparing the compound fertilizer slurry within a short distance range from the urea molten liquid, so as to achieve the characteristics of long-distance transportation without generating biuret; the present utility model uses the different properties of the urea molten liquid and the compound fertilizer slurry, and the compound fertilizer slurry is not easy to generate biuret to transform the corresponding equipment. The urea molten liquid produced in the urea production unit is directly fed into the compound fertilizer mixing tank and compounded with other raw materials, and is directly used for the production of compound fertilizer particles on the basis of preparing the compound fertilizer slurry; in order to achieve energy conservation and consumption reduction, reduce production costs, and on the basis of avoiding the large floor area occupied by the layout of the urea production unit and the compound fertilizer production unit together, reduce the content of biuret in the product and ensure the product quality. Brief Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of the present utility model;

[0018] Figure 2 is another schematic structural diagram of the present utility model;

[0019] Legend Explanation:

[0020] 1. Compound fertilizer mixing tank; 2. Slurry pump; 3. Long-distance conveying pipeline; 4. Urea secondary evaporation separator; 5. Melting pump; 6. Urea granulation tower; 7. Urea granulation nozzle; 8. First three-way; 9. First control valve; 10. Second control valve; 11. Compound fertilizer granulation tower; 12. Compound fertilizer granulation nozzle; 13. Temperature sensor; 14. Second three-way; 15. Third control valve; 16. Fourth control valve; 17. Stirring heating tank; 18. Urea molten liquid inlet; 19. First heat exchange coil; 20. First screw feeder; 21. Slurry inlet; 22. Second heat exchange coil; 23. Steam pipe network; 24. Condensate storage tank; 25. Stirring motor; 26. Stirring shaft; 27. Stirring blades; 28. Different particle size packaging systems; 29. Product conveyor belt; 30. Fertilizer vibrating screen; 31. Second screw feeder. Detailed Embodiments

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0022] Referring to Figure 1-2 , a high-concentration urea-based compound fertilizer production system of the present utility model, the production system includes a urea production unit. The urea molten liquid outlet pipeline in the urea production unit is connected to a compound fertilizer mixing tank 1 arranged around the urea production unit. The bottom of the compound fertilizer mixing tank 1 is connected to the compound fertilizer production unit through a slurry pump 2 and a long-distance conveying pipeline 3. According to the characteristic that high-concentration urea-based compound fertilizer slurry is not easy to produce biuret, the present utility model arranges the compound fertilizer mixing tank 1 near the urea production unit to reduce the conveying distance of the urea molten liquid, so as to reduce steam consumption and production cost when producing high-concentration urea-based compound fertilizer. The above design can avoid the problem of excessive floor area caused by the urea production unit and the compound fertilizer production unit being in the same area, and at the same time can ensure the quality of the compound fertilizer and avoid the defect of too high biuret content. It should be noted that: the compound fertilizer mixing tank 1 adopted in the present utility model is made of stainless steel, an atmospheric pressure device, with a volume of 10m 3 .

[0023] Furthermore, the urea production unit includes a urea secondary evaporation separator 4. The outlet of the urea secondary evaporation separator 4 is connected to a urea granulation nozzle 7 in a urea granulation tower 6 through a melting pump 5. A first three-way joint 8 and a first control valve 9 are successively arranged on the pipeline between the melting pump 5 and the urea granulation tower 6; the third end of the first three-way joint 8 is connected to the compound fertilizer mixing tank 1 through a second control valve 10. The urea molten liquid used in the present utility model comes from the urea secondary evaporation separator 4, and the concentration of the urea molten liquid is about 99.6%, with the characteristic of low water content, thus avoiding the defect that the high water content of the compound fertilizer slurry affects the quality of the compound fertilizer in the subsequent process. The above setting can realize the feature of introducing the urea molten liquid into the compound fertilizer mixing tank 1 without destroying the original urea production unit, that is: the present utility model can be used to produce urea and / or high-concentration urea-based compound fertilizer according to actual situations.

[0024] Furthermore, the compound fertilizer production unit at least includes a compound fertilizer granulation tower 11. The compound fertilizer granulation nozzle 12 in the compound fertilizer granulation tower 11 is connected to the end of the long-distance conveying pipeline 3 through a pipeline. The present utility model realizes the production of compound fertilizer slurry by arranging the compound fertilizer mixing tank 1, thereby omitting the relevant equipment for melting urea particles and also omitting the relevant equipment for mixing raw materials, so as to achieve the purpose of reducing investment cost and energy consumption.

[0025] Further, a temperature sensor 13 is provided at the end of the long-distance conveying pipeline 3. A second three-way valve 14 is provided between the long-distance conveying pipeline 3 and the compound fertilizer granulating nozzle 12. The second end of the second three-way valve 14 is connected to the compound fertilizer granulating nozzle 12 through a third control valve 15. The third end of the second three-way valve 14 is connected to the stirring and heating tank 17 through a fourth control valve 16. The outlet of the stirring and heating tank 17 is connected to the compound fertilizer granulating nozzle 12. In the present utility model, the length of the long-distance conveying pipeline 3 is determined based on the distance between the urea production unit and the compound fertilizer production unit. Based on this, during the process of the long-distance conveying pipeline 3 transporting the compound fertilizer slurry, the temperature of the slurry will inevitably be lost. When the heat loss is small or the formula ratio can meet the operation requirements of the compound fertilizer granulating nozzle 12, the compound fertilizer slurry can be directly transported to the compound fertilizer granulating nozzle 12; when the heat loss is large and does not meet the operation requirements of the compound fertilizer granulating nozzle 12 or new formula raw materials need to be added, the compound fertilizer slurry can be directly transported to the stirring and heating tank 17 for full mixing, stirring and heating, and then sent to the compound fertilizer granulating nozzle 12 to prepare compound fertilizer particles. Therefore, the temperature sensor 13 in the present utility model is used to detect the temperature of the compound fertilizer slurry at the end of the long-distance conveying pipeline 3 in real time.

[0026] Further, the compound fertilizer stirring tank 1 includes a urea molten liquid inlet 18 provided at the upper part of the compound fertilizer stirring tank 1, and a slurry outlet provided at the lower part of the compound fertilizer stirring tank 1 and connected to the slurry pump 2. A first stirring part is provided inside the compound fertilizer stirring tank 1, and a first heat exchange coil 19 is provided inside the compound fertilizer stirring tank 1; a first screw feeder 20 is provided at the top of the compound fertilizer stirring tank 1. In the present utility model, the first screw feeder 20 is used to transport other basic raw materials into the compound fertilizer stirring tank 1 to be mixed with the urea molten liquid to prepare a compound fertilizer slurry. The other basic raw materials are ammonium chloride, potassium chloride, potassium sulfate, phosphoric acid ammonium, etc.; the material in the compound fertilizer stirring tank 1 is heated and insulated through the first heat exchange coil 19 to keep the slurry in a molten state, and the first stirring part is used to achieve full mixing of the materials.

[0027] Further, the stirring and heating tank 17 includes a slurry inlet 21 provided at the upper part of the stirring and heating tank 1, and a slurry outlet provided at the lower part of the stirring and heating tank 1. A second stirring part is provided inside the stirring and heating tank 1, a second heat exchange coil 22 is provided inside the compound fertilizer stirring tank 17, and a second screw feeder 31 is provided at the top of the stirring and heating tank 17. By providing the stirring and heating tank 17, it is mainly to achieve uniform mixing of the slurry and reheat it to meet the operation requirements of the compound fertilizer granulating nozzle 12; in the present utility model, the second screw feeder 31 is provided on the stirring and heating tank 17, which can achieve quantitative addition of new raw materials through the second screw feeder 31 when adding new formula raw materials.

[0028] Further, both the first heat exchange coil 19 and the second heat exchange coil 22 are heat exchange coils. The lower inlet of the heat exchange coil is connected to the steam pipe network 23, and the upper outlet of the heat exchange coil is connected to the condensate storage tank 24.

[0029] Further, both the first stirring part and the second stirring part are stirring parts. The stirring part includes a stirring motor 25. The main shaft of the stirring motor 25 is connected to the stirring shaft 26, and stirring blades 27 are arranged on the stirring shaft 26 extending into the tank.

[0030] Further, a product conveyor belt 29 is provided at the bottom of the compound fertilizer granulation tower 11. The end of the product conveyor belt 29 is provided with a fertilizer vibrating screen 30. Different outlets of the fertilizer vibrating screen 30 are respectively connected to different particle size packaging systems 28. Preferably, the different particle size packaging systems 28 can be three separate packaging systems, and their particle size specifications are 0 - 2.0 mm, 2.0 - 3.35 mm, and 3.35 - 4.75 mm respectively.

[0031] The working principle of the present utility model: The present utility model is an improvement based on the existing urea production unit with the purpose of not destroying the existing urea production, that is: it can be used to produce urea alone, high - concentration urea - based compound fertilizer, and simultaneously produce urea and high - concentration urea - based compound fertilizer. When only urea production or co - production of urea is required, the original process can be used for production, which will not be elaborated here; when high - concentration urea - based compound fertilizer needs to be produced, the urea melt with a concentration of about 99.6% from the urea secondary evaporation separator 4 enters the compound fertilizer stirring tank 1 through the melting pump 5, the third end of the first three - way valve 8, and the second control valve 10. The flow rate of the urea melt at the outlet of the melting pump 5 is 10m 3 / h to 15m 3 / h; Taking potassium chloride as the basic raw material as an example, potassium chloride is conveyed into the compound fertilizer mixing tank 1 by the first spiral feeder 20. The mass ratio of the urea melt to potassium chloride is 85:15. The above two are stirred and heated in the compound fertilizer mixing tank 1 to become a compound fertilizer slurry. The compound fertilizer slurry enters the long-distance conveying pipeline 3 under the pressure of the slurry pump 2. The temperature sensor 13 is used to detect the temperature of the compound fertilizer slurry at the end of the long-distance conveying pipeline 3. When the temperature of the compound fertilizer slurry meets the operating requirements of the compound fertilizer granulating nozzle 12, the compound fertilizer slurry can be directly conveyed to the compound fertilizer granulating nozzle 12 for granulation. When the temperature of the compound fertilizer slurry fails to meet the operating requirements of the compound fertilizer granulating nozzle 12 or new formula raw materials are added, the compound fertilizer slurry can be directly conveyed to the stirring and heating tank 17 for full mixing, stirring and heating (when new formula raw materials are added, the new raw materials can be quantitatively input through the second spiral feeder 31), and then sent to the compound fertilizer granulating nozzle 12 to prepare compound fertilizer particles. The compound fertilizer particles enter the lower part of the compound fertilizer granulating tower 11 under the action of gravity and are conveyed to the fertilizer vibrating screen 30 by the product conveyor belt 29 for vibrating screening. Different outlets of the fertilizer vibrating screen 30 enter different particle size packaging systems 28 for packaging and external sales. It has the characteristics of energy conservation and consumption reduction, reducing production costs, reducing the biuret content in the product and ensuring product quality on the basis of avoiding the over-large floor area occupied by the urea production unit and the compound fertilizer production unit being arranged together.

[0032] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-concentration urea-based compound fertilizer production system, characterized in that: The production system includes a urea production unit. The outlet pipeline of the urea melt in the urea production unit is connected to a compound fertilizer stirring tank (1) arranged around the urea production unit. The bottom of the compound fertilizer stirring tank (1) is connected to a compound fertilizer production unit through a slurry pump (2) and a long-distance conveying pipeline (3). The urea production unit includes a urea secondary evaporation separator (4). The outlet of the urea secondary evaporation separator (4) is connected to a urea granulation nozzle (7) in a urea granulation tower (6) through a melting pump (5). A first three-way valve (8) and a first control valve (9) are successively arranged on the pipeline between the melting pump (5) and the urea granulation tower (6). The third end of the first three-way valve (8) is connected to the compound fertilizer stirring tank (1) through a second control valve (10).

2. The high-concentration urea-based compound fertilizer production system according to claim 1, characterized in that: The compound fertilizer production unit at least includes a compound fertilizer granulation tower (11). The compound fertilizer granulation nozzle (12) in the compound fertilizer granulation tower (11) is connected to the end of the long-distance conveying pipeline (3) through a pipeline.

3. The high-concentration urea-based compound fertilizer production system according to claim 2, wherein: A temperature sensor (13) is arranged at the end of the long-distance conveying pipeline (3). A second three-way valve (14) is arranged between the long-distance conveying pipeline (3) and the compound fertilizer granulation nozzle (12). The second end of the second three-way valve (14) is connected to the compound fertilizer granulation nozzle (12) through a third control valve (15). The third end of the second three-way valve (14) is connected to a stirring and heating tank (17) through a fourth control valve (16). The outlet of the stirring and heating tank (17) is connected to the compound fertilizer granulation nozzle (12).

4. A high-concentration urea-based compound fertilizer production system according to claim 3, characterized in that: The compound fertilizer stirring tank (1) includes a urea melt inlet (18) arranged at the upper part of the compound fertilizer stirring tank (1), and a slurry outlet arranged at the lower part of the compound fertilizer stirring tank (1) and connected to the slurry pump (2). A first stirring part is arranged inside the compound fertilizer stirring tank (1), and a first heat exchange coil (19) is arranged inside the compound fertilizer stirring tank (1). A first screw feeder (20) is arranged at the top of the compound fertilizer stirring tank (1).

5. A high-concentration urea-based compound fertilizer production system according to claim 4, characterized in that: The stirring and heating tank (17) includes a slurry inlet (21) arranged at the upper part of the stirring and heating tank (1), and a slurry outlet arranged at the lower part of the stirring and heating tank (1). A second stirring part is arranged inside the stirring and heating tank (1), a second heat exchange coil (22) is arranged inside the stirring and heating tank (1), and a second screw feeder (31) is arranged at the top of the stirring and heating tank (1).

6. The high-concentration urea-based compound fertilizer production system according to claim 5, characterized in that: Both the first heat exchange coil (19) and the second heat exchange coil (22) are heat exchange coils. The lower inlet of the heat exchange coil is connected to a steam pipe network (23), and the upper outlet of the heat exchange coil is connected to a condensate storage tank (24).

7. A high-concentration urea-based compound fertilizer production system according to claim 5, characterized in that: Both the first stirring part and the second stirring part are stirring parts. The stirring part includes a stirring motor (25). The main shaft of the stirring motor (25) is connected to a stirring shaft (26). Stirring blades (27) are arranged on the stirring shaft (26) extending into the tank.

8. A high-concentration urea-based compound fertilizer production system according to claim 3, characterized in that: A product conveyor belt (29) is arranged at the bottom of the compound fertilizer granulation tower (11). A fertilizer vibrating screen (30) is arranged at the end of the product conveyor belt (29). Different outlets of the fertilizer vibrating screen (30) are respectively connected to different particle size packaging systems (28).

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