Drying device used in compound fertilizer production process

Abstract

The utility model belongs to a drying device used in the production process of compound fertilizer. Comprising a monoammonium phosphate storage tank and a compound fertilizer production system, the monoammonium phosphate storage tank is connected with a drying unit through a monoammonium phosphate quantitative feeding system, and an outlet of the drying unit is connected with a primary tank in the compound fertilizer production system through a second elevator; the monoammonium phosphate quantitative feeding system is arranged to be matched with the drying unit, so that the raw material monoammonium phosphate can be fully dried, and the characteristic that the purchasing cost of the monoammonium phosphate or the field manual picking and checking labor intensity is reduced is achieved.

Description

Technical Field

[0001] This utility model belongs to the field of compound fertilizer production technology, and specifically relates to a drying device used in the compound fertilizer production process for drying raw material monoammonium phosphate. Background Technology

[0002] The main production steps of the high-tower compound fertilizer process include: monoammonium phosphate is transported to the feeding pit by a crane, then conveyed to the primary tank by a weighing scale and a scraper conveyor to be melted and mixed with raw materials such as potassium chloride; granulation, cooling, screening, coating, and packaging are then performed by the high-tower granulator. Currently, the moisture evaporation effect after cooling and screening of the high-tower compound fertilizer product is not significant, resulting in excessive moisture content and product clumping.

[0003] To address the aforementioned technical challenges, most companies employ methods to control the moisture content of raw materials. Specifically, to reduce the final moisture content of high-tower compound fertilizers, the selected raw materials are typically required to have a moisture content below 1.0%. However, mainstream monoammonium phosphate (MAP) is produced using a wet process, resulting in a moisture content generally around 2.0%. Consequently, controlling the moisture content of MAP requires manual inspection, which is labor-intensive and inaccurate. Other companies, to ensure the MAP moisture content remains below 1.0%, choose to directly purchase this type of MAP. The purchase price per ton is generally about 30 yuan higher than that of conventional MAP, thus increasing the production cost of compound fertilizers. Utility Model Content

[0004] The purpose of this invention is to overcome the defects in the prior art and provide a drying device used in the production process of compound fertilizer.

[0005] The above-mentioned technical objective of this utility model is achieved through the following technical solution:

[0006] A drying device used in the production of compound fertilizer includes a monoammonium phosphate storage tank and a compound fertilizer production system. The monoammonium phosphate storage tank is connected to the drying unit through a monoammonium phosphate quantitative feeding system, and the outlet of the drying unit is connected to the primary tank in the compound fertilizer production system through a second elevator.

[0007] The beneficial effects of this utility model are as follows: by setting up a quantitative feeding system for monoammonium phosphate in conjunction with a drying unit, the raw material monoammonium phosphate can be fully dried, thereby reducing the purchase cost of monoammonium phosphate or the labor intensity of on-site manual inspection.

[0008] Preferably, the drying unit includes a drying section and a recovery section; the drying section includes a vibrating fluidized bed connected to the outlet of the monoammonium phosphate quantitative feeding system, the bottom of the vibrating fluidized bed is provided with a hot air inlet, the hot air inlet is connected to the air channel outlet of the air heater through a variable frequency hot air blower, and the air channel inlet of the air heater is connected to the atmosphere.

[0009] Preferably, the recovery section includes a gas phase outlet at the top of the vibrating fluidized bed, which is connected to a bag filter. The gas phase outlet of the bag filter is connected to the atmosphere via an induced draft fan. The solid phase outlet of the bag filter and the solid phase outlet of the vibrating fluidized bed are respectively connected to a scraper conveyor. The scraper conveyor is connected to the inlet of the second elevator via a weighing scale.

[0010] Preferably, the recovery unit further includes a heating channel inlet connected to a steam pipe, a heating channel outlet connected to an insulated pipe located outside the bag filter, and an outlet connected to an external condensate delivery pipe.

[0011] Preferably, the monoammonium phosphate quantitative feeding system includes a first elevator connected to a monoammonium phosphate storage tank. The first elevator is connected to a metering auger in sequence via a crusher and a buffer tank. The outlet of the metering auger is connected to the inlet of a vibrating fluidized bed in the drying unit.

[0012] This utility model also includes a control system, which includes a PLC controller. The signal input terminal of the PLC controller is connected to the moisture detector, and the signal output terminal of the PLC controller is connected to at least a valve located at the inlet of the heating channel of the air heater. The moisture detector is located between the solid phase outlet of the vibrating fluidized bed and the scraper conveyor.

[0013] Preferably, the signal output terminal of the PLC controller is also electrically connected to the variable frequency hot air blower.

[0014] Preferably, the signal output terminal of the PLC controller is also electrically connected to the metering auger.

[0015] A drying device for use in the production process of compound fertilizer according to the above scheme is mainly used when feeding monoammonium phosphate. It utilizes a quantitative feeding system for monoammonium phosphate in conjunction with the drying unit to achieve thorough drying of monoammonium phosphate, thereby ensuring the quality of the final compound fertilizer product. At the same time, this utility model adopts a drying method in which steam and air are exchanged for heat and then dried in a vibrating fluidized bed. This method can achieve thorough drying of monoammonium phosphate. Meanwhile, a bag filter is used to recover the dust-laden monoammonium phosphate, and the condensate from the heat exchanged steam is used to keep the bag filter warm, thereby achieving the characteristics of saving energy, reducing monoammonium phosphate loss, and ensuring the long-term stable operation of the entire equipment. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of this utility model.

[0018] In the image above:

[0019] 1. First elevator; 2. Crusher; 3. Buffer tank; 4. Metering auger; 5. Vibrating fluidized bed; 6. Scraper conveyor; 7. Bag filter; 8. Exhaust fan; 9. Metering scale; 10. Second elevator; 11. Primary tank; 12. Valve; 13. Air heater; 14. Variable frequency hot air blower; 15. PLC controller; 16. Moisture analyzer; 17. Monoammonium phosphate storage tank; 18. Steam pipeline; 19. Insulated pipeline; 20. Condensate delivery pipeline. Detailed Implementation

[0020] The technical solution of this utility model will now be clearly and completely described with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0021] Reference Figure 1 This invention relates to a drying device used in the production of compound fertilizer. The drying device includes a monoammonium phosphate (MAP) storage tank 17 and a compound fertilizer production system. The MAP storage tank 17 is connected to the drying unit via a MAP quantitative feeding system. The outlet of the drying unit is connected to the primary tank 11 in the compound fertilizer production system via a second elevator 10. This invention is applicable to drying the MAP during the feeding stage of compound fertilizer production. By drying the raw materials, the moisture content of the finished compound fertilizer is reduced, avoiding the need for purchasing low-moisture MAP at high prices or manually inspecting and processing the MAP.

[0022] Furthermore, the drying unit includes a drying section and a recovery section; the drying section includes a vibrating fluidized bed 5 connected to the outlet of the monoammonium phosphate quantitative feeding system, the bottom of the vibrating fluidized bed 5 is provided with a hot air inlet, the hot air inlet is connected to the air channel outlet of the air heater 13 through a variable frequency hot air blower 14, and the air channel inlet of the air heater 13 is connected to the atmosphere. This invention achieves the drying of monoammonium phosphate by setting a drying section in the drying unit, and simultaneously recovers the heat energy of the monoammonium phosphate and the medium used for drying the monoammonium phosphate by setting a recovery section, thereby saving raw materials and reducing energy consumption. The drying section of this invention includes a vibrating fluidized bed 5. Air is heated through the air channel of the air heater 13, and the heated air after heat exchange is about 130°C. Under the action of the variable frequency hot air blower 14, it is transported to the lower part of the vibrating fluidized bed 5. The monoammonium phosphate entering the vibrating fluidized bed 5 is dried through the fluidizing perforated plate in the vibrating fluidized bed 5. Preferably, the moisture content of the monoammonium phosphate is reduced to below 0.5%, thereby reducing the moisture content of the compound fertilizer product, ensuring its quality and preventing it from clumping. The air heater 13 is used to heat the air, and the heating method can be conventional electric heating, steam heating, or heat transfer oil heating. The vibrating fluidized bed 5 of this invention is preferably made of carbon steel.

[0023] Furthermore, the recovery unit includes a gas phase outlet at the top of the vibrating fluidized bed 5, which is connected to a bag filter 7. The gas phase outlet of the bag filter 7 is connected to the atmosphere via an induced draft fan 8. The solid phase outlets of the bag filter 7 and the vibrating fluidized bed 5 are respectively connected to a scraper conveyor 6, which is connected to the inlet of the second elevator 10 via a weighing scale 9. The recovery unit in this invention can include the recovery of monoammonium phosphate dust discharged from the vibrating fluidized bed 5 to avoid the waste of raw materials. At the same time, the weighing scale 9 is used to weigh the monoammonium phosphate to ensure that the nutrients in the compound fertilizer meet the corresponding standards. The above-mentioned setup enables continuous production of compound fertilizer.

[0024] Furthermore, the recovery unit also includes a heating channel inlet connected to a steam pipe 18, a heating channel outlet connected to an insulated pipe 19 located outside the bag filter 7, and an outlet connected to an external condensate delivery pipe 20. In addition to recovering monoammonium phosphate from the drying exhaust gas, the recovery unit in this invention also recovers heat energy. The heat source for heating in the air heater 13 is preferably steam, specifically 0.5 MPa steam, which heats the air in the air channel of the air heater 13. The heated steam condensate is then sent into the insulated pipe 19 to insulate the bag filter 7, thereby achieving the recovery and reuse of waste heat.

[0025] Furthermore, the monoammonium phosphate quantitative feeding system includes a first elevator 1 connected to the monoammonium phosphate storage tank 17. The first elevator 1 is connected to a metering auger 4 via a crusher 2 and a buffer tank 3. The outlet of the metering auger 4 is connected to the inlet of the vibrating fluidized bed 5 in the drying unit. The monoammonium phosphate quantitative feeding system described in this invention is used for pretreatment of monoammonium phosphate. This pretreatment not only prepares for the production of compound fertilizer products but also lays the foundation for the thorough drying of monoammonium phosphate. Specifically, it achieves quantitative feeding of monoammonium phosphate to the vibrating fluidized bed 5 based on the crushing of monoammonium phosphate, thereby enabling the thorough drying of monoammonium phosphate.

[0026] This invention also includes a control system, which comprises a PLC controller 15. The signal input terminal of the PLC controller 15 is connected to a moisture detector 16, and the signal output terminal of the PLC controller 15 is connected to at least a valve 12 located at the inlet of the heating channel of the air heater 13. The moisture detector 16 is located between the solid phase outlet of the vibrating fluidized bed 5 and the scraper conveyor 6. This invention can be used for manual drying or automatic drying. When the moisture detector 16 detects that the moisture content of the monoammonium phosphate exceeds the standard, the temperature of the air in the air heater 13 can be controlled by increasing the opening of the valve 12, thereby reducing the moisture content of the monoammonium phosphate.

[0027] Furthermore, the signal output terminal of the PLC controller 15 is also electrically connected to the variable frequency hot air blower 14. In addition to adjusting the moisture content of monoammonium phosphate using the aforementioned methods, it can also be adjusted by regulating the amount of hot air entering the vibrating fluidized bed 5.

[0028] Furthermore, the signal output terminal of the PLC controller 15 is also electrically connected to the metering auger 4. Besides adjusting the moisture content of monoammonium phosphate using the aforementioned methods, it can also be adjusted by reducing the amount of monoammonium phosphate entering the vibrating fluidized bed 5. This invention can use either the individual technical solutions described above to adjust the moisture content of monoammonium phosphate, or a combination of the above technical solutions to adjust the moisture content of monoammonium phosphate.

[0029] The working principle of this utility model is as follows: The monoammonium phosphate (MAP) in the storage tank 17 has a moisture content of about 2%. It is fed to the crusher 2 via the first elevator 1. The crushed MAP enters the buffer bin 3, and then is sent to the vibrating fluidized bed 5 for drying via the metering auger 4. After drying, the MAP is tested for moisture content by the analyzer 16, and then sent to the primary tank 11 by the scraper conveyor 6, the metering scale 9, and the second elevator 10 for melting and production of compound fertilizer. At the same time, 0.5 MPa steam in the steam pipe 18 enters the air heater 13 through the valve 12 to heat the air. The heated air enters the vibrating fluidized bed 5 as a heat source to dry the MAP. The dusty exhaust gas after drying enters the bag filter 7 for dust removal. The dusty gas phase is discharged by the induced draft fan 8, and the solid dust enters the scraper conveyor 6 through the solid phase outlet of the bag filter 7 for recycling. The aforementioned steam heating... The condensate after air exposure enters the insulated pipe 19 outside the bag filter 7 to insulate the bag filter 7. The insulated condensate is then discharged to the subsequent condensate collection section through the external condensate delivery pipe 20. The moisture detector 16 described in this invention detects the moisture content of the raw material in real time and feeds it back to the PLC controller 15. When the water content is too high, it can be adjusted by regulating the opening of the valve 12, the frequency of the variable frequency hot air blower 14, and / or the amount fed into the vibrating fluidized bed 5 by the metering auger 4. This invention can control the moisture content of the raw material monoammonium phosphate to below 0.5%. At the same time, the equipment of this invention has a fully enclosed structure and has the characteristics of good environmental protection. Furthermore, this invention can simultaneously supply raw materials to multiple compound fertilizer granulation towers, thereby improving the production efficiency of compound fertilizer. The moisture content of the compound fertilizer produced by this invention can be significantly reduced, thereby avoiding the phenomenon of compound fertilizer caking.

[0030] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A drying device used in a compound fertilizer production process, the drying device comprising a monoammonium phosphate storage tank (17) and a compound fertilizer production system, characterized in that: The monoammonium phosphate storage tank (17) is connected to the drying unit through the monoammonium phosphate quantitative feeding system, and the outlet of the drying unit is connected to the primary tank (11) in the compound fertilizer production system through the second elevator (10).

2. The drying device used in a compound fertilizer production process according to claim 1, characterized in that: The drying unit includes a drying section and a recycling section; The drying section includes a vibrating fluidized bed (5) connected to the outlet of the monoammonium phosphate quantitative feeding system. The bottom of the vibrating fluidized bed (5) is provided with a hot air inlet. The hot air inlet is connected to the air channel outlet of the air heater (13) through a variable frequency hot air blower (14). The air channel inlet of the air heater (13) is connected to the atmosphere.

3. The drying device used in a compound fertilizer production process according to claim 2, characterized in that: The recovery section includes a gas phase outlet at the top of the vibrating fluidized bed (5), which is connected to a bag filter (7). The gas phase outlet of the bag filter (7) is connected to the atmosphere through an induced draft fan (8). The solid phase outlet of the bag filter (7) and the solid phase outlet of the vibrating fluidized bed (5) are respectively connected to a scraper conveyor (6). The scraper conveyor (6) is connected to the inlet of the second elevator (10) through a weighing scale (9).

4. The drying device used in a compound fertilizer production process according to claim 3, characterized in that: The recovery unit also includes a heating channel inlet of the air heater (13) connected to a steam pipe (18), a heating channel outlet of the air heater (13) connected to an insulated pipe (19) located outside the bag filter (7), and an outlet of the insulated pipe (19) connected to an external condensate delivery pipe (20).

5. The drying device used in a compound fertilizer production process according to any one of claims 2-4, characterized in that: The monoammonium phosphate quantitative feeding system includes a first elevator (1) connected to a monoammonium phosphate storage tank (17). The first elevator (1) is connected to a metering auger (4) in sequence through a crusher (2) and a buffer tank (3). The outlet of the metering auger (4) is connected to the inlet of the vibrating fluidized bed (5) in the drying unit.

6. The drying device used in a compound fertilizer production process according to claim 1, characterized in that: It also includes a control system, which includes a PLC controller (15). The signal input terminal of the PLC controller (15) is connected to the moisture detector (16), and the signal output terminal of the PLC controller (15) is connected to at least the valve (12) located at the inlet of the heating channel of the air heater (13). A moisture meter (16) is installed between the solid phase outlet of the vibrating fluidized bed (5) and the scraper conveyor (6).

7. The drying apparatus for use in a compound fertilizer production process according to claim 6, characterized in that: The signal output terminal of the PLC controller (15) is also electrically connected to the variable frequency hot air blower (14).

8. The drying device used in a compound fertilizer production process according to claim 6 or 7, characterized in that: The signal output terminal of the PLC controller (15) is also electrically connected to the metering auger (4).

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