Urea formaldehyde preparation system

Abstract

The utility model relates to the technical field of urea formaldehyde compound fertilizer production, and discloses a urea formaldehyde preparation system, which comprises a reaction tank and an intermediate tank, the reaction tank is communicated with a water inlet pipe, an air inlet pipe, a feed inlet and a liquid outlet pipe; a first conveying pump is arranged on the liquid outlet pipe; the other end of the liquid outlet pipe is communicated with a middle tank, the middle tank is communicated with a discharging pipe, a second conveying pump is arranged on the discharging pipe, a plurality of spray heads are arranged at the other end of the discharging pipe, and the spray heads extend into a secondary dryer or a granulator. According to the scheme, urea and formaldehyde react to form the urea formaldehyde solution, and then the urea formaldehyde solution is sprayed on the surface of the compound fertilizer to form the urea formaldehyde slow-release compound fertilizer, so that the coating uniformity of urea formaldehyde on the surface of the compound fertilizer is effectively improved, and the slow-release uniformity of the urea formaldehyde compound fertilizer is improved.

Description

Technical Field

[0001] This invention relates to the field of urea-formaldehyde compound fertilizer production technology, specifically to a urea-formaldehyde preparation system. Background Technology

[0002] Urea-formaldehyde, as an important slow-release nitrogen fertilizer and chemical raw material, has wide applications in agriculture, plastics, and wood processing. As market demands for the quality and yield of urea-formaldehyde products continue to increase, traditional preparation systems are struggling to meet these needs. For example, in agriculture, there is a need to produce urea-formaldehyde slow-release fertilizers with more controllable nutrient release rates and higher fertilizer efficiency; in industry, the requirements for the purity and stability of urea-formaldehyde resins are becoming increasingly stringent. This necessitates the development of more efficient, stable, and precise urea-formaldehyde preparation systems.

[0003] Traditional urea-formaldehyde production processes typically involve two steps in a reactor: a hydroxylation reaction in an alkaline environment followed by a methylenelation reaction in an acidic environment. This intermittent production method suffers from a complex and cumbersome process, high labor costs, and the inability to achieve continuous industrial production. Furthermore, the reactors require a large footprint, and expanding production capacity necessitates a significant increase in both equipment space and investment. Additionally, the lack of parallelism between reactions can lead to substantial fluctuations in product quality.

[0004] Based on the above problems, the existing technology CN113999074A discloses a high-strength compound fertilizer and its preparation method. First, an acidic solution is mixed with a formaldehyde solution to obtain an acidic formaldehyde solution with a pH of 4-6. Then, urea, monoammonium phosphate, and an alkaline substance are mixed at 90-130℃ to form a eutectic with a pH of 8-9. During the granulation process, the eutectic and the acidic formaldehyde solution are sprayed onto the surface of the compound fertilizer. After the eutectic and the acidic formaldehyde solution come into contact on the surface of the compound fertilizer, they react to generate urea-formaldehyde that coats at least part of the surface of the compound fertilizer, thus obtaining a high-strength compound fertilizer. However, the existing technology still has the following technical problems: (1) The existing technology sprays the eutectic and acidic formaldehyde solution onto the surface of the compound fertilizer separately during the granulation stage for reaction coating, which results in poor uniformity of urea-formaldehyde coating on the surface of the compound fertilizer, significantly reducing the slow-release effect of the compound fertilizer; (2) The existing method of spraying and coating compound fertilizer to prepare urea-formaldehyde slow-release compound fertilizer requires two sprayings, which is not only complicated to control, but also easily prolongs the production process of high-strength compound fertilizer, which not only increases energy consumption, but also reduces production efficiency and production benefits.

[0005] Therefore, developing a urea-formaldehyde preparation system can not only effectively make up for the shortcomings of existing technologies, but also effectively improve the production efficiency of urea-formaldehyde and reduce energy consumption, which is of great significance for improving enterprise benefits. Summary of the Invention

[0006] The present invention aims to provide a urea-formaldehyde preparation system to solve the technical problem that existing urea-formaldehyde systems, when sprayed separately and then reacted on the surface of compound fertilizers, tend to have uneven coating of urea-formaldehyde on the surface of the compound fertilizer.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a urea-formaldehyde preparation system, comprising a reaction tank and an intermediate tank, wherein the reaction tank is connected to a water inlet pipe, an air inlet pipe, a feed inlet and a liquid outlet pipe; a first delivery pump is provided on the liquid outlet pipe; the other end of the liquid outlet pipe is connected to the intermediate tank, the intermediate tank is connected to a discharge pipe, a second delivery pump is provided on the discharge pipe, and a plurality of nozzles are provided on the other end of the discharge pipe, the nozzles extending into a secondary dryer or a granulator.

[0008] The principle and advantages of this scheme are:

[0009] 1. Compared to existing methods where urea and formaldehyde are sprayed separately and then reacted on the surface of compound fertilizer, resulting in uneven coating of urea and formaldehyde, this solution first reacts urea and formaldehyde to form a urea-formaldehyde solution, and then sprays it onto the surface of the compound fertilizer to form a slow-release urea-formaldehyde compound fertilizer. This effectively improves the uniformity of urea and formaldehyde coating on the surface of the compound fertilizer and enhances the uniformity of slow-release of urea-formaldehyde compound fertilizer.

[0010] 2. This solution effectively improves the stability of urea-formaldehyde coating by spraying it onto the compound fertilizer material in the granulator or secondary dryer, thereby enhancing the slow-release stability and efficacy of the urea-formaldehyde compound fertilizer. Specifically, when the applicant previously attempted to spray urea-formaldehyde solution onto the compound fertilizer in the primary dryer, the high moisture content and insufficient strength of the compound fertilizer easily led to changes in product particle size, affecting the compound fertilizer production efficiency. This solution sprays urea-formaldehyde onto the material in the granulator or secondary dryer, effectively improving the overall quality of the compound fertilizer.

[0011] Preferably, as an improvement, the water inlet pipe is provided with a water inlet valve, the air inlet pipe is provided with an air inlet valve, the liquid outlet pipe is provided with a liquid outlet valve, and the material outlet pipe is provided with a material outlet valve.

[0012] Technical benefits: The above-mentioned setup facilitates the adjustment and control of the inlet of water and formaldehyde, and the delivery of urea-formaldehyde solution.

[0013] Preferably, as an improvement, the reaction tank is also equipped with a heater, a stirrer, a thermometer, and a pH meter.

[0014] Technical Benefits: This scheme, employing the above-described setup, facilitates the monitoring and adjustment of the solution's state during the reaction process. The heater, which can be a heating resistor or a jacket, is used to heat the solution within the reaction tank. A stirrer is used to agitate the solution during the reaction; a thermometer is used to detect the temperature of the solution within the reaction tank; and a pH meter is used to detect the pH of the solution within the reaction tank.

[0015] Preferably, as an improvement, the tops of the reaction tank and the intermediate tank are respectively connected to exhaust pipes, which are connected to a dust collector.

[0016] Technical benefits: The above-mentioned setup facilitates the collection and treatment of exhaust gases in the reaction tank and intermediate tank.

[0017] Preferably, as an improvement, a controller is also provided, which is electrically connected to the heater, stirrer, thermometer, pH meter, water inlet valve, air inlet valve, liquid outlet valve, material outlet valve, first delivery pump and second delivery pump. The controller is equipped with several control buttons and a display screen.

[0018] Technical effect: This solution uses the above settings to display temperature, pH and the status of each electrical device, enabling remote monitoring of the entire process.

[0019] Preferably, as an improvement, a cooling pipe is also connected between the reaction tank and the intermediate tank, and the cooling pipe is equipped with a graphite heat exchanger, a cooling valve and a third delivery pump.

[0020] Technical Benefits: This solution, employing the above-mentioned setup, allows for rapid cooling of the urea-formaldehyde solution within the reaction tank via cooling pipes and a graphite heat exchanger. This facilitates handling situations where urea-formaldehyde solution is urgently needed to spray and coat compound fertilizer within the plant area. Of course, even if rapid cooling of the urea-formaldehyde solution is not required, it can also serve as an alternative to the outlet pipe, allowing for continuous production of the reaction tank while maintaining the outlet pipe and related equipment during maintenance. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the urea-formaldehyde preparation system in Example 1 of the present invention.

[0022] Figure 2 This is a schematic diagram of the urea-formaldehyde preparation system in Embodiment 2 of the present invention. Detailed Implementation

[0023] The following detailed description illustrates the specific implementation method:

[0024] The reference numerals in the accompanying drawings include: reaction tank 1, water inlet pipe 11, water inlet valve 111, air inlet pipe 12, air inlet valve 121, feed port 13, liquid outlet pipe 14, liquid outlet valve 141, first transfer pump 142, stirrer 15, thermometer 16, pH meter 17, cooling pipe 18, cooling valve 181, third transfer pump 182, graphite heat exchanger 183, intermediate tank 2, discharge pipe 21, discharge valve 211, second transfer pump 212, and exhaust pipe 3.

[0025] Example 1

[0026] This solution provides a urea-formaldehyde preparation system, as shown in the attached diagram. Figure 1As shown: The system includes a reaction tank 1 and an intermediate tank 2. The reaction tank 1 is connected to a water inlet pipe 11, an air inlet pipe 12, a feed inlet 13, and a liquid outlet pipe 14. The water inlet pipe 11 is equipped with a water inlet valve 111, and the air inlet pipe 12 is equipped with an air inlet valve 121. The other end of the air inlet pipe 12 is connected to a formaldehyde tank (not shown in the figure). The feed inlet 13 is used to feed urea and caustic soda flakes. The liquid outlet pipe 14 is equipped with a liquid outlet valve 141 and a first delivery pump 142. The other end of the liquid outlet pipe 14 is connected to the intermediate tank 2, which is connected to a discharge pipe 21. The discharge pipe 21 is equipped with a discharge valve 211 and a second delivery pump 212. The other end of the discharge pipe 21 is equipped with several nozzles that extend into a secondary dryer or granulator. This facilitates controlled spraying of urea-formaldehyde solution onto the surface of the compound fertilizer, encapsulating the compound fertilizer to form a slow-release urea-formaldehyde compound fertilizer.

[0027] The reaction tank 1 is also equipped with a heater, a stirrer 15, a thermometer 16, and a pH meter 17. The heater can be a heating resistor or a jacket; in this embodiment, it is specifically a jacketed heater (not shown in the figure), used to heat the solution in the reaction tank 1. The stirrer 15 is used to stir the solution in the reaction tank 1 during the reaction process; the thermometer 16 is used to detect the temperature of the solution in the reaction tank 1, and the pH meter 17 is used to detect the pH of the solution in the reaction tank 1.

[0028] The tops of the reaction tank 1 and the intermediate tank 2 are respectively connected to the exhaust gas pipe 3, which is connected to the dust collector. In this embodiment, the dust collector is a Venturi scrubber, which collects and treats the exhaust gas in the reaction tank 1 and the intermediate tank 2.

[0029] The system also includes a controller, which is electrically connected to the heater, stirrer 15, thermometer 16, pH meter 17, water inlet valve 111, air inlet valve 121, liquid outlet valve 141, material outlet valve 211, first transfer pump 142, and second transfer pump 212. The controller has several control buttons and a display screen showing the temperature, pH, and status of each electrical device, used for remote monitoring of the entire process. All electrical equipment used in this solution is existing equipment; its structure and function will not be described in detail here.

[0030] Specific implementation process:

[0031] Activate the inlet valve 111, heater, and stirrer 15 via the buttons on the controller to add water and urea to reaction tank 1. After adding water, close the inlet valve 111 and continue heating and stirring to accelerate urea dissolution. Then, activate the air inlet valve 121 to introduce formaldehyde into reaction tank 1. Stir the reaction until all formaldehyde has been added. After complete heating and stirring, a urea-formaldehyde solution is obtained. Close the air inlet valve 121 and then add caustic soda flakes to adjust the pH of the solution to 8-9. Throughout the process, control the solution temperature below 80℃ to prevent excessively rapid exothermic reaction and overflow. If the temperature is too high, lower the temperature or slow down the formaldehyde introduction rate.

[0032] Subsequently, the liquid outlet valve 141 and the first transfer pump 142 are activated to transport the urea-formaldehyde solution in reaction tank 1 to intermediate tank 2 for temporary storage via pipeline. Finally, according to the compound fertilizer production process, the discharge valve 211 and the second transfer pump 212 are activated to transport the urea-formaldehyde solution to the granulator or secondary dryer, and then spray it onto the surface of the rotary granulator or rotary dryer through a nozzle to coat the compound fertilizer and form a urea-formaldehyde slow-release compound fertilizer.

[0033] Example 2

[0034] To further improve the cooling rate of the urea-formaldehyde solution, the difference between this embodiment and Example 1 is that, as... Figure 2 As shown, a cooling pipe 18 is connected between the reaction tank 1 and the intermediate tank 2. The cooling pipe 18 is equipped with a graphite heat exchanger 183, a cooling valve 181 and a third delivery pump 182.

[0035] In this embodiment, the urea-formaldehyde solution in the reaction tank 1 can be rapidly cooled via cooling pipe 18 and graphite heat exchanger 183, facilitating the handling of urgent situations requiring urea-formaldehyde solution spraying and coating of compound fertilizer within the factory area. Of course, even if rapid cooling of the urea-formaldehyde solution is not required, it can also serve as an alternative to the outlet pipe 14, allowing for continuous production in the reaction tank 1 while maintaining the outlet pipe 14 and related equipment. Specifically, after one batch of urea-formaldehyde solution is prepared in the reaction tank 1, the solution can be transported to the intermediate tank 2 via cooling pipe 18 or outlet pipe 17, emptying the reaction tank 2 for the preparation of the next batch of urea-formaldehyde solution; during this process, the other pipeline equipment not involved in the urea-formaldehyde solution transport can be maintained.

[0036] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A urea-formaldehyde preparation system, characterized in that: It includes a reaction tank and an intermediate tank. The reaction tank is connected to a water inlet pipe, an air inlet pipe, a feed inlet, and a liquid outlet pipe. A first conveying pump is installed on the liquid outlet pipe. The other end of the liquid outlet pipe is connected to the intermediate tank, which is connected to a discharge pipe. A second conveying pump is installed on the discharge pipe. Several nozzles are installed at the other end of the discharge pipe, and the nozzles extend into a secondary dryer or granulator.

2. The urea-formaldehyde preparation system according to claim 1, characterized in that: The water inlet pipe is equipped with a water inlet valve, the air inlet pipe is equipped with an air inlet valve, the liquid outlet pipe is equipped with a liquid outlet valve, and the material outlet pipe is equipped with a material outlet valve.

3. The urea-formaldehyde preparation system according to claim 2, characterized in that: The reaction tank is also equipped with a heater, a stirrer, a thermometer, and a pH meter.

4. The urea-formaldehyde preparation system according to claim 1, characterized in that: The tops of the reaction tank and the intermediate tank are respectively connected to exhaust pipes, which are connected to a dust collector.

5. The urea-formaldehyde preparation system according to claim 1, characterized in that: It is also equipped with a controller, which is electrically connected to the heater, stirrer, thermometer, pH meter, water inlet valve, air inlet valve, liquid outlet valve, material outlet valve, first delivery pump and second delivery pump. The controller is equipped with several control buttons and a display screen.

6. The urea-formaldehyde preparation system according to claim 1, characterized in that: A cooling pipe is also connected between the reaction tank and the intermediate tank. The cooling pipe is equipped with a graphite heat exchanger, a cooling valve and a third delivery pump.

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