Device for continuously producing urea formaldehyde slow-release fertilizer

Abstract

The utility model relates to a device for continuously producing a urea formaldehyde slow-release fertilizer. Comprising a urea supply unit and a formaldehyde solution storage tank, the urea supply unit and the formaldehyde solution storage tank are respectively connected with a hydroxymethyl urea continuous production unit, the urea supply unit and the hydroxymethyl urea continuous production unit are respectively connected with a urea formaldehyde continuous unit, and the urea formaldehyde continuous unit is connected with a potassium nitrate compound fertilizer system; the hydroxymethyl urea production unit comprises a first ultrasonic mixer; the first ultrasonic mixer is connected with the urea formaldehyde continuous unit through a first micro-channel reactor; the urea formaldehyde continuous unit comprises a second ultrasonic mixer, the second ultrasonic mixer passes through a second microchannel reactor, and an outlet of the second microchannel reactor is connected with a potassium nitrate compound fertilizer system. The method has the characteristics that the aim of increasing the reaction rate is fulfilled by utilizing the characteristics of the micro-channel reactor on the basis of fully mixing the raw materials, and the continuous production of hydroxymethyl urea and urea formaldehyde is realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to urea formaldehyde slow release fertilizer production field, specifically a kind of continuous production urea formaldehyde slow release fertilizer's device. BACKGROUND

[0002] Urea formaldehyde fertilizer is a kind of chemical synthesis slow-release fertilizer, which is generated by condensation reaction of urea and formaldehyde solution. Urea formaldehyde is a pioneer product of slow-release fertilizer, which was commercialized in 1955. It is mainly used in golf courses, flowers, gardening and other non-agricultural markets; urea formaldehyde slow-release fertilizer is prepared by the reaction of 6%-15% polyoxymethylene and urea, and compared with ordinary urea, urea formaldehyde slow-release fertilizer can reduce 37% nitrogen loss, has high nitrogen utilization rate and reduces environmental pollution; the existing urea formaldehyde production mainly uses reaction kettle to realize condensation reaction after long-time stirring to make materials fully mixed; the above process has the defects of high energy consumption and intermittent production. SUMMARY

[0003] In order to make up for the above shortcomings, the utility model provides a kind of continuous production urea formaldehyde slow-release fertilizer's device to solve the technical problems existing in prior art.

[0004] The technical scheme adopted by the utility model to solve its technical problems is:

[0005] A kind of continuous production urea formaldehyde slow-release fertilizer's device, the device includes urea supply unit and formaldehyde solution storage tank, the urea supply unit and formaldehyde solution storage tank are connected with hydroxymethyl urea continuous production unit respectively, urea supply unit and hydroxymethyl urea continuous production unit are connected with urea formaldehyde continuous unit respectively, urea formaldehyde continuous unit is connected with potassium nitrate compound fertilizer system;The hydroxymethyl urea production unit includes the first ultrasonic mixer connected with urea supply unit and formaldehyde solution storage tank, the first ultrasonic mixer is connected with urea formaldehyde continuous unit by first microchannel reactor;The urea formaldehyde continuous unit includes the second ultrasonic mixer connected with first microchannel reactor and urea supply unit, the second ultrasonic mixer passes through second microchannel reactor, and the outlet of second microchannel reactor is connected with potassium nitrate compound fertilizer system.

[0006] The utility model discloses the beneficial effect is: the utility model discloses a hydroxymethyl urea continuous production unit and urea formaldehyde continuous unit are set up to realize the continuous production to urea formaldehyde, further, realize the continuous production to urea formaldehyde slow release fertilizer through potassium nitrate compound fertilizer system to reach the characteristics of urea formaldehyde slow release fertilizer continuous production and the production efficiency is improved, the utility model discloses the production characteristics of urea formaldehyde, and the hydroxymethyl urea continuous production unit and urea formaldehyde continuous unit are specially set up, and the above -mentioned two continuous production units are provided with ultrasonic mixer respectively in advance to realize the full mixing of raw materials, and the purpose of improving the reaction rate is realized on the basis of the full mixing of raw materials by the characteristics of micro -channel reactor, and the above -mentioned setting can realize the characteristics of continuous production hydroxymethyl urea and urea formaldehyde respectively, and further, the purpose of effectively reducing energy consumption can be achieved due to the improvement of reaction rate.

[0007] Preferably, the hydroxymethyl urea production unit further comprises a first pH meter and a first three-way valve arranged between the first ultrasonic mixer and the first micro-channel reactor, and a third end of the first three-way valve is connected with a sodium hydroxide storage tank.

[0008] Preferably, the urea formaldehyde continuous unit further comprises a second pH meter and a second three-way valve arranged between the second ultrasonic mixer and the second micro-channel reactor, and a third end of the second three-way valve is connected with a hydrogen chloride storage tank.

[0009] Preferably, the first micro-channel reactor is further provided with a first temperature control part, the first temperature control part comprises a first heat exchange channel and a second heat exchange channel of the first micro-channel reactor, the first ultrasonic mixer is connected with an inlet of the second ultrasonic mixer through the first heat exchange channel of the first micro-channel reactor, and an outlet of the second heat exchange channel of the first micro-channel reactor is connected with an inlet of the second heat exchange channel of the first micro-channel reactor through a first flow meter, a first heat exchanger and a first heat pump; and the first heat exchange channel outlet of the first micro-channel reactor is provided with a hydroxymethyl urea pump.

[0010] Preferably, the second micro-channel reactor is further provided with a second temperature control part, the second temperature control part comprises a first heat exchange channel and a second heat exchange channel of the second micro-channel reactor, the second ultrasonic mixer is connected with the potassium nitrate compound fertilizer system through the first heat exchange channel of the second micro-channel reactor, and an outlet of the second heat exchange channel of the second micro-channel reactor is connected with an inlet of the second heat exchange channel of the second micro-channel reactor through a second flow meter, a second heat exchanger and a second heat pump.

[0011] Preferably, the potassium nitrate compound fertilizer system comprises a urea formaldehyde buffer tank connected with an outlet of the first heat exchange channel of the second micro-channel reactor and a potassium nitrate preparation device, the urea formaldehyde buffer tank is connected with an inlet of a granulation device through a urea formaldehyde metering pump, the potassium nitrate preparation device is connected with the inlet of the granulation device, and an outlet of the granulation device is connected with a urea formaldehyde slow release fertilizer packaging device through a drying device.

[0012] Preferably, the urea supply unit comprises a urea solution flash tank, an outlet of the urea solution flash tank is connected with a urea solution storage tank through a urea delivery pump, the urea solution storage tank is connected with the first ultrasonic mixer through a third three-way pipe and a first urea solution metering pump, a third end of the third three-way pipe is connected with the second ultrasonic mixer through a second urea solution metering pump.

[0013] Preferably, a formaldehyde solution metering pump is arranged between the formaldehyde solution storage tank and the first ultrasonic mixer.

[0014] The device for continuously producing urea-formaldehyde slow-release fertilizer according to the above scheme realizes continuous production of urea-formaldehyde slow-release fertilizer by arranging a methylol urea continuous production unit for continuously producing monomethylol urea and dimethylol urea, arranging a urea-formaldehyde continuous unit for continuously producing urea-formaldehyde, and further realizing continuous production of urea-formaldehyde slow-release fertilizer by using the urea-formaldehyde to enter a potassium nitrate compound fertilizer system, so that continuous production of urea-formaldehyde slow-release fertilizer is realized, production efficiency is improved, and the purpose is achieved; the ultrasonic mixer arranged in the device is used to realize sufficient mixing of raw materials, and the coupling of the microchannel reactor and the urea-formaldehyde slow-release fertilizer preparation device can accelerate the reaction process, shorten the reaction time, and improve the reaction yield when preparing urea-formaldehyde slow-release fertilizer; on the other hand, the intermittent reaction can be changed into a continuous reaction, work efficiency is improved, the quality of the product is improved, and the production cost is reduced; furthermore, the raw materials in the microchannel reactor are relatively less, and the reaction speed is relatively fast, so that the energy consumption for controlling the reaction temperature can be effectively reduced, and the energy consumption is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0016] Figure 1 It is a structural schematic diagram of the present application.

[0017] In the figure: 1, urea solution flash tank; 2, urine delivery pump; 3, urea solution storage tank; 4, first urea solution metering pump; 5, second urea solution metering pump; 6, formaldehyde solution storage tank; 7, first ultrasonic mixer; 8, first micro-channel reactor; 9, second ultrasonic mixer; 10, second micro-channel reactor; 11, first pH meter; 12, sodium hydroxide storage tank; 13, second pH meter; 14, hydrogen chloride storage tank; 15, first heat exchange pump; 16, first heat exchanger; 17, first flow meter; 18, hydroxymethyl urea pump; 19, second heat exchange pump; 20, second heat exchanger; 21, second flow meter; 22, potassium nitrate preparation device; 23, urea-formaldehyde metering pump; 24, granulation device; 25, drying device; 26, urea-formaldehyde slow-release fertilizer packaging device; 27, first three-way joint; 28, second three-way joint; 29, third three-way joint; 30, urea-formaldehyde buffer tank; 31, formaldehyde solution metering pump. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. Figure 1The utility model discloses a continuous production urea formaldehyde slow release fertilizer's device, and the device includes urea supply unit and formaldehyde solution storage tank 6, urea supply unit and formaldehyde solution storage tank 6 are connected with hydroxymethyl urea continuous production unit respectively, and urea supply unit and hydroxymethyl urea continuous production unit are connected with urea formaldehyde continuous unit respectively, and urea formaldehyde continuous unit is connected with potassium nitrate compound fertilizer system, the hydroxymethyl urea production unit includes the first ultrasonic mixer 7 connected with urea supply unit and formaldehyde solution storage tank 6, and the first ultrasonic mixer 7 is connected with urea formaldehyde continuous unit through the first microchannel reactor 8, and the urea formaldehyde continuous unit includes the second ultrasonic mixer 9 connected with the first microchannel reactor 8 and urea supply unit, and the second ultrasonic mixer 9 is connected with the second microchannel reactor 10 through the second microchannel reactor 10, and the outlet of the second microchannel reactor 10 is connected with potassium nitrate compound fertilizer system, the utility model discloses overcome the defect that need in the reaction kettle through long time stirring to carry out condensation reaction in traditional technology, and the continuous production of urea formaldehyde is realized through setting hydroxymethyl urea continuous production unit and urea formaldehyde continuous unit, further, the continuous production of urea formaldehyde slow release fertilizer is realized through potassium nitrate compound fertilizer system, to reach the characteristics of urea formaldehyde slow release fertilizer continuous production and the production efficiency is improved, in the utility model, the hydroxymethyl urea continuous production unit and urea formaldehyde continuous unit are specially set up for the production characteristics of urea formaldehyde, and the above-mentioned two continuous production units are respectively provided with ultrasonic mixer to realize the full mixing of raw materials, and the purpose of improving reaction rate is realized by utilizing the characteristics of microchannel reactor on the basis of the full mixing of raw materials, and the above-mentioned setting can realize the characteristics of continuous production of hydroxymethyl urea and urea formaldehyde respectively.

[0020] Further, the hydroxymethyl urea production unit further includes a first pH meter 11 and a first three-way valve 27 arranged between the first ultrasonic mixer 7 and the first microchannel reactor 8, and a third end of the first three-way valve 27 is connected with a sodium hydroxide storage tank 12. Through the above arrangement, the amount of material in the first microchannel reactor 8 can be monitored, and the reaction under alkaline conditions in the first microchannel reactor 8 can be realized.

[0021] Further, the urea formaldehyde continuous unit further includes a second pH meter 13 and a second three-way valve 28 arranged between the second ultrasonic mixer 9 and the second microchannel reactor 10, and a third end of the second three-way valve 28 is connected with a hydrogen chloride storage tank 14. Through the above arrangement, the amount of material in the second microchannel reactor 10 can be monitored, and the reaction under acidic conditions in the second microchannel reactor 10 can be realized.

[0022] Further, the first micro-channel reactor 8 is further provided with a first temperature control unit, the first temperature control unit comprising a first heat exchange channel and a second heat exchange channel of the first micro-channel reactor 8, the first ultrasonic mixer 7 being connected to the inlet of the second ultrasonic mixer 9 through the first heat exchange channel of the first micro-channel reactor 8, the outlet of the second heat exchange channel of the first micro-channel reactor 8 being connected to the inlet of the second heat exchange channel of the first micro-channel reactor 8 through the first flow meter 17, the first heat exchanger 16 and the first heat pump 15; the outlet of the first heat exchange channel of the first micro-channel reactor 8 is provided with a hydroxymethyl urea pump 18. Through the above arrangement, the temperature of the material in the first micro-channel reactor 8 can be controlled to meet the reaction requirements and improve the reaction rate.

[0023] Further, the second micro-channel reactor 10 is further provided with a second temperature control unit, the second temperature control unit comprising a first heat exchange channel and a second heat exchange channel of the second micro-channel reactor 10, the second ultrasonic mixer 9 being connected to the potassium nitrate compound fertilizer system through the first heat exchange channel of the second micro-channel reactor 10, the outlet of the second heat exchange channel of the second micro-channel reactor 10 being connected to the inlet of the second heat exchange channel of the second micro-channel reactor 10 through the second flow meter 21, the second heat exchanger 20 and the second heat pump 19. Through the above arrangement, the temperature of the material in the second micro-channel reactor 10 can be controlled to meet the reaction requirements and improve the reaction rate.

[0024] Further, the potassium nitrate compound fertilizer system comprises a urea-formaldehyde buffer tank 30 connected to the outlet of the first heat exchange channel of the second micro-channel reactor 10 and a potassium nitrate preparation device 22, the urea-formaldehyde buffer tank 30 being connected to the inlet of a granulation device 24 through a urea-formaldehyde metering pump 23, the potassium nitrate preparation device 22 being connected to the inlet of the granulation device 14, the outlet of the granulation device 24 being connected to a urea-formaldehyde slow-release fertilizer packaging device 26 through a drying device 25. Through the above arrangement, the continuous production of potassium nitrate compound fertilizer can be realized.

[0025] Further, the urea supply unit comprises a urea solution flash tank 1, the outlet of the urea solution flash tank 1 being connected to a urea solution storage tank 3 through a urea solution pump 2, the urea solution storage tank 3 being connected to the first ultrasonic mixer 7 through a first urea solution metering pump 4 and a first three-way valve 29, the third end of the first three-way valve 29 being connected to the second ultrasonic mixer 9 through a second urea solution metering pump 5.

[0026] Further, a formaldehyde solution metering pump 31 is arranged between the formaldehyde solution storage tank 6 and the first ultrasonic mixer 7.

[0027] The specific working process of the utility model is as follows: the method for preparing urea-formaldehyde slow-release fertilizer comprises the following steps: step one: the urea solution storage tank 3, the urea solution in the urea solution storage tank 3 is the urea solution from the urea solution flash tank 1 of synthetic ammonia system, the urea solution is sent into the first ultrasonic mixer 7 through the first urea solution metering pump 4; the concentration of the urea solution is 65%-85%. The temperature of the urea solution storage tank 3 is kept at 80-100 DEG C. Step two: the urea solution and formaldehyde solution in the first ultrasonic mixer 7 are transmitted to the urea solution and formaldehyde solution in the mixer through the ultrasonic generator in the ultrasonic mixer, then under the ultrasonic suction and release, the solution repeatedly stirs, rubs, compresses and stretches, completes the homogenization work, makes the urea solution and formaldehyde solution fully mix uniformly, then enters the first microchannel reactor 8 through the first pH measuring meter 11. The temperature in the first ultrasonic mixer 7 is 60-80 DEG C, the pressure is 0.01-0.05 MPa, the reaction residence time is 10 s-1 min, and the ultrasonic frequency is 25-130 KHz. The amount-of-substance ratio of the urea and formaldehyde is (5-5.6):1. Step three: the homogeneous solution of urea and formaldehyde in step two is first measured for pH value through the first pH measuring meter 11, then the amount of sodium hydroxide solution to be added is determined according to the pH value. The homogeneous solution of urea and formaldehyde is under alkaline condition in the first microchannel reactor 8, and addition reaction occurs to generate monomethylol urea and dimethylol urea. The reactants enter the second ultrasonic mixer 9 through the monomethylol urea pump 18. The alkaline range in the first microchannel reactor 8 is pH=7-9, and the temperature is 60-80 DEG C. Step four: the urea solution and monomethylol urea and dimethylol urea in the second ultrasonic mixer 9 are transmitted to the urea solution and monomethylol urea in the mixer through the ultrasonic generator in the ultrasonic mixer, then under the ultrasonic suction and release, the solution repeatedly stirs, rubs, compresses and stretches, completes the homogenization work, makes the urea solution and monomethylol urea and dimethylol urea fully mix uniformly, then enters the second microchannel reactor 10 through the second pH measuring meter 13. The amount-of-substance ratio of the urea and monomethylol urea and dimethylol urea is (1-1.4):1, and the temperature is 50-70 DEG C. Step five: the homogeneous solution of urea and monomethylol urea and dimethylol urea in step four is measured for pH value through the second pH measuring meter 13, the amount of hydrogen chloride solution to be added is determined according to the pH value, and then enters the second microchannel reactor 10. Under acidic condition, urea and monomethylol urea and dimethylol urea occur condensation reaction to form a mixture of part or most of the methylene urea, dimethylene triurea and trimethylene tetraurea molecules which are insoluble in water, collectively referred to as urea-formaldehyde. The acidic range in the microchannel reactor is pH=4-6, and the temperature is 50-70 DEG C.Step six: urea-formaldehyde in the urea-formaldehyde buffer tank 30 is metered by the metering pump 24 into the granulation device 24, while the potassium nitrate in the potassium nitrate preparation device 22 is also metered into the granulation device 24 for granulation. The prepared urea-formaldehyde slow-release compound fertilizer is dried by the drying device 25 and packaged by the urea-formaldehyde slow-release fertilizer packaging device 26, and then sold.

[0028] The urea solution from the urea solution flash tank 1 enters the urea solution storage tank 3 through the urine delivery pump 2, the urea solution is sent into the first ultrasonic mixer 7 through the first urea solution metering pump 4, simultaneously, the formaldehyde solution is sent into the first ultrasonic mixer 7 through the formaldehyde solution storage tank 6 and the formaldehyde solution metering pump 31, the urea solution and the formaldehyde solution transmit high-frequency ultrasonic signals to the urea solution and the formaldehyde solution in the first ultrasonic mixer 7 through the ultrasonic generator, then, under the ultrasonic absorption and release, the solution repeatedly stirs, rubs, compresses and stretches, the homogenization work is completed, the urea solution and the formaldehyde solution are fully mixed and uniform, the mixed solution measures the pH value through the first pH meter 11, since the above-mentioned solution carries out the hydroxymethylation reaction in the first microchannel reactor 8, it needs to carry out under the alkaline condition, the pH value can be adjusted through the sodium hydroxide in the sodium hydroxide storage tank 12 when the pH value is too low, the amount of sodium hydroxide can be determined through the amount of solution and the pH value, simultaneously, the first temperature control part can control the temperature in the first microchannel reactor 8, so that the reaction efficiency is improved, the above-mentioned solution adjusts the pH value through sodium hydroxide, enters the first microchannel reactor 8 and controls the temperature through the first temperature control part, under the above-mentioned working condition, the homogeneous solution of urea and formaldehyde generates addition reaction to generate monohydroxymethyl urea and dihydroxymethyl urea.The utility model discloses a kind of preparation urea-formaldehyde slow-release fertilizer's method using microchannel reaction device, through the coupling of microchannel reaction device and urea-formaldehyde slow-release fertilizer preparation device, on the one hand, it can accelerate reaction process when preparing urea-formaldehyde slow-release, shorten reaction time, improve reaction yield;On the other hand, it can be intermittent reaction into continuous reaction, improve work efficiency, to reach the quality of product while reducing production cost The advantage of improving, with industrialized development prospect.

[0029] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the utility model. Without departing from the spirit and scope of the utility model, the utility model can also have various changes and improvements. These changes and improvements fall within the scope of the claimed utility model.

Claims

1. A device for continuous production of urea formaldehyde slow release fertilizer, which comprises a urea supply unit and a formaldehyde solution tank (6), characterized in that: The urea supply unit and the formaldehyde solution storage tank (6) are connected with the methylol urea continuous production unit respectively, the urea supply unit and the methylol urea continuous production unit are connected with the urea-formaldehyde continuous unit respectively, and the urea-formaldehyde continuous unit is connected with the potassium nitrate compound fertilizer system; The methylol urea production unit comprises a first ultrasonic mixer (7) connected with the urea supply unit and the formaldehyde solution storage tank (6), and the first ultrasonic mixer (7) is connected with the urea-formaldehyde continuous unit through a first micro-channel reactor (8). The urea-formaldehyde continuous unit comprises a second ultrasonic mixer (9) connected with the first micro-channel reactor (8) and the urea supply unit, and the second ultrasonic mixer (9) is connected with the potassium nitrate compound fertilizer system through a second micro-channel reactor (10).

2. A device for continuously producing urea formaldehyde slow release fertilizer according to claim 1, characterized in that: The methylol urea production unit further comprises a first pH meter (11) and a first three-way valve (27) arranged between the first ultrasonic mixer (7) and the first micro-channel reactor (8), and a third end of the first three-way valve (27) is connected with a sodium hydroxide storage tank (12).

3. A device for continuously producing urea formaldehyde slow release fertilizer according to claim 1, characterized in that: The urea-formaldehyde continuous unit further comprises a second pH meter (13) and a second three-way valve (28) arranged between the second ultrasonic mixer (9) and the second micro-channel reactor (10), and a third end of the second three-way valve (28) is connected with a hydrogen chloride storage tank (14).

4. The apparatus for continuously producing urea-formaldehyde slow release fertilizer according to claim 1 or 2, characterized in that: The first micro-channel reactor (8) is further provided with a first temperature control part, the first temperature control part comprises a first heat exchange channel and a second heat exchange channel of the first micro-channel reactor (8), the first ultrasonic mixer (7) is connected with an inlet of the second ultrasonic mixer (9) through the first heat exchange channel of the first micro-channel reactor (8), an outlet of the second heat exchange channel of the first micro-channel reactor (8) is connected with an inlet of the second heat exchange channel of the first micro-channel reactor (8) through a first flow meter (17), a first heat exchanger (16) and a first heat pump (15), and an outlet of the first heat exchange channel of the first micro-channel reactor (8) is provided with a methylol urea pump (18).

5. The apparatus for continuously producing urea-formaldehyde slow release fertilizer according to claim 1 or 3, characterized in that: The second micro-channel reactor (10) is further provided with a second temperature control part, the second temperature control part comprises a first heat exchange channel and a second heat exchange channel of the second micro-channel reactor (10), The second ultrasonic mixer (9) is connected with the potassium nitrate compound fertilizer system through the first heat exchange channel of the second micro-channel reactor (10), and an outlet of the second heat exchange channel of the second micro-channel reactor (10) is connected with an inlet of the second heat exchange channel of the second micro-channel reactor (10) through a second flow meter (21), a second heat exchanger (20) and a second heat pump (19).

6. The apparatus for continuously producing urea formaldehyde slow release fertilizer according to claim 1 or 3, characterized in that: The potassium nitrate compound fertilizer system comprises a urea formaldehyde buffer tank (30) connected with the first heat exchange channel outlet of the second micro-channel reactor (10) and a potassium nitrate preparation device (22), the urea formaldehyde buffer tank (30) is connected with the inlet of a granulation device (24) through a urea formaldehyde metering pump (23), the potassium nitrate preparation device (22) is connected with the inlet of the granulation device (24), and the outlet of the granulation device (24) is connected with a urea formaldehyde slow-release fertilizer packaging device (26) through a drying device (25).

7. The apparatus for continuously producing urea formaldehyde slow release fertilizer according to claim 1, wherein: The urea supply unit comprises a urea solution flash tank (1), the outlet of the urea solution flash tank (1) is connected with a urea solution storage tank (3) through a urea delivery pump (2), the urea solution storage tank (3) is connected with a first urea solution metering pump (4) and a first ultrasonic mixer (7) through a third three-way valve (29), and the third end of the third three-way valve (29) is connected with a second ultrasonic mixer (9) through a second urea solution metering pump (5).

8. The apparatus for continuously producing urea formaldehyde slow release fertilizer according to claim 1, wherein: A formaldehyde solution metering pump (31) is arranged between the formaldehyde solution storage tank (6) and the first ultrasonic mixer (7).

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