A continuous production device for urotropine

Abstract

This utility model discloses a continuous production equipment for urotropine, comprising: a liquid ammonia storage tank, an ammonia source switching mechanism, a liquid ammonia vaporizer, a formaldehyde feeding device, and a microchannel reactor. The liquid ammonia storage tank has a liquid ammonia outlet and a gas phase outlet. The first inlet of the ammonia source switching mechanism is connected to the liquid ammonia outlet of the liquid ammonia storage tank, and the second inlet is connected to the gas phase outlet of the liquid ammonia storage tank. The ammonia source switching mechanism also has a switching outlet. The inlet of the liquid ammonia vaporizer is connected to the switching outlet of the ammonia source switching mechanism, and the liquid ammonia vaporizer has an ammonia gas outlet. The formaldehyde feeding device has a formaldehyde outlet. The microchannel reactor has an ammonia gas inlet, a formaldehyde inlet, and a reaction liquid outlet. This utility model enables the continuous reaction of formaldehyde and ammonia while avoiding safety accidents caused by excessive pressure in the liquid ammonia storage tank.

Description

Technical Field

[0001] This utility model relates to a continuous production equipment for hexamethylenetetramine. Background Technology

[0002] Currently, the industrial production of urotropine mainly employs a process involving the reaction of formaldehyde and ammonia. Traditional production methods often use batch reactors, which suffer from long reaction times, low raw material utilization, and unstable product quality. Particularly in terms of process control, the process relies heavily on manual operation to control the formaldehyde and ammonia feed rates, with the reaction endpoint determined by on-site pH testing. This can easily lead to excessive ammonia injection, resulting in raw material waste and increased production costs. Furthermore, batch production makes precise material proportioning difficult, has low heat removal efficiency, and poses safety hazards.

[0003] A search of existing technologies revealed a Chinese patent (CN205774232U) disclosing an automated control production system for formaldehyde and hexamethylenetetramine processes. This system includes a formaldehyde purification tower and a hexamethylenetetramine reactor. Raw materials are introduced into the reactor through a refined formaldehyde outlet and an ammonia pipeline for reaction, and a defoaming device is included to improve reaction efficiency. However, this technology relies on a single ammonia source supply method, making it unable to cope with fluctuations in ammonia supply or equipment malfunctions, thus affecting the stability of continuous production. Summary of the Invention

[0004] The technical problem to be solved by this utility model is to overcome the defects of the prior art and provide a continuous production equipment for hexamethylenetetramine, which can realize the continuous reaction of formaldehyde and ammonia, while avoiding safety accidents caused by excessive pressure in the liquid ammonia storage tank.

[0005] To solve the above-mentioned technical problems, the technical solution of this utility model is: a continuous production equipment for hexamethylenetetramine, comprising:

[0006] A liquid ammonia storage tank, wherein the liquid ammonia storage tank is provided with a liquid ammonia outlet and a gas phase outlet;

[0007] An ammonia source switching mechanism is provided, wherein the first inlet of the ammonia source switching mechanism is connected to the liquid ammonia outlet of the liquid ammonia storage tank, the second inlet is connected to the gas phase outlet of the liquid ammonia storage tank, and the ammonia source switching mechanism is provided with a switching outlet.

[0008] A liquid ammonia vaporizer, wherein the inlet of the liquid ammonia vaporizer is connected to the switching outlet of the ammonia source switching mechanism, and the liquid ammonia vaporizer is provided with an ammonia outlet;

[0009] A formaldehyde supply device, wherein the formaldehyde supply device is provided with a formaldehyde outlet;

[0010] A microchannel reactor is provided with an ammonia inlet, a formaldehyde inlet, and a reaction liquid outlet. The ammonia inlet is connected to the ammonia outlet of the liquid ammonia vaporizer, the formaldehyde inlet is connected to the formaldehyde outlet of the formaldehyde feeding device, and the reaction liquid outlet is suitable for outputting hexamethylenetetramine reaction liquid.

[0011] Furthermore, a specific type of ammonia source switching mechanism is provided, wherein the ammonia source switching mechanism is a three-way switching valve.

[0012] Furthermore, the continuous production equipment for hexamethylenetetramine also includes an ammonia filter, which is located between the ammonia outlet of the liquid ammonia vaporizer and the ammonia inlet of the microchannel reactor.

[0013] Furthermore, the continuous production equipment for urotropine also includes a formaldehyde mass flow meter, a formaldehyde flow regulating valve, an ammonia flow meter, an ammonia flow regulating valve, and a controller;

[0014] The formaldehyde mass flow meter is installed on the pipeline between the formaldehyde outlet of the formaldehyde feeding device and the formaldehyde inlet of the microchannel reactor.

[0015] The formaldehyde flow regulating valve is located between the formaldehyde mass flow meter and the formaldehyde inlet of the microchannel reactor.

[0016] The ammonia flow meter is installed on the pipeline between the ammonia outlet of the liquid ammonia vaporizer and the ammonia inlet of the microchannel reactor.

[0017] The ammonia flow regulating valve is located between the switching outlet of the ammonia source switching mechanism and the inlet of the liquid ammonia vaporizer;

[0018] The controller is electrically connected to the formaldehyde mass flow meter, the formaldehyde flow regulating valve, the ammonia flow meter, and the ammonia flow regulating valve, respectively. The controller is adapted to adjust the opening of the formaldehyde flow regulating valve and the ammonia flow regulating valve according to the formaldehyde flow signal from the formaldehyde mass flow meter and the ammonia flow signal from the ammonia flow meter, so as to adjust the feed ratio of formaldehyde and ammonia.

[0019] Furthermore, the liquid ammonia vaporizer is provided with a heat exchange medium inlet and a heat exchange medium outlet;

[0020] The reaction liquid outlet of the microchannel reactor is connected to the heat exchange medium inlet of the liquid ammonia vaporizer, and the heat exchange medium outlet is adapted to output hexamethylenetetramine reaction liquid.

[0021] Furthermore, the continuous production equipment for hexamethylenetetramine also includes a reaction liquid heat exchanger and a second circulating water supply pipe and a second circulating water return pipe.

[0022] The reaction liquid heat exchange cooler is installed on the downstream pipeline of the heat exchange medium outlet of the liquid ammonia vaporizer. The reaction liquid heat exchange cooler is provided with a cooler inlet, a cooler outlet, a cooling medium inlet, and a cooling medium outlet.

[0023] The inlet of the heat exchanger of the reaction liquid is connected to the outlet of the heat exchange medium of the liquid ammonia vaporizer, and the outlet of the heat exchanger is adapted to output the hexamethylenetetramine reaction liquid.

[0024] The second circulating water supply pipe is connected to the cooling medium inlet of the reaction liquid heat exchanger, and the second circulating water return pipe is connected to the cooling medium outlet of the reaction liquid heat exchanger.

[0025] Furthermore, the continuous production equipment for hexamethylenetetramine also includes a reaction liquid temperature sensor, a cooling medium flow regulating valve, and a controller;

[0026] The reaction liquid temperature sensor is installed on the downstream pipe of the cooler outlet of the reaction liquid heat exchanger, and the reaction liquid temperature sensor is adapted to detect the temperature of the reaction liquid and send a temperature signal.

[0027] The cooling medium flow regulating valve is installed on the second circulating water supply pipe;

[0028] The controller is connected to the reaction liquid temperature sensor and the cooling medium flow regulating valve respectively, and the controller is adapted to adjust the opening of the cooling medium flow regulating valve according to the temperature signal of the reaction liquid temperature sensor.

[0029] Furthermore, the continuous production equipment for urotropine also includes a near-infrared analyzer and a pH sensor;

[0030] The near-infrared analyzer and pH sensor are respectively installed on the downstream pipeline of the reaction liquid outlet of the microchannel reactor (6). The near-infrared analyzer detects the formaldehyde content of the reaction liquid in the pipeline of the reaction liquid outlet in real time and sends out a formaldehyde content signal. The pH sensor is suitable for detecting the pH value of the reaction liquid in the pipeline of the reaction liquid outlet and sending out a pH value signal.

[0031] The controller is also connected to the near-infrared analyzer. The controller is adapted to adjust the opening of the ammonia flow regulating valve according to the formaldehyde content signal from the near-infrared analyzer, and is adapted to control the alarm to issue an alarm signal when the pH value signal received from the pH sensor exceeds the preset range.

[0032] Furthermore, the continuous production equipment for urotropine also includes pressure sensors and controllers;

[0033] The pressure sensor is installed on the liquid ammonia storage tank, and the pressure sensor is adapted to detect the pressure of the liquid ammonia storage tank and send a pressure signal.

[0034] The controller is electrically connected to the pressure sensor and the three-way switching valve respectively. The controller is adapted to control the three-way switching valve to switch between the first inlet and the switching outlet and the second inlet and the switching outlet according to the pressure signal of the pressure sensor.

[0035] By adopting the above technical solution, this utility model has the following beneficial effects:

[0036] In this invention, under normal circumstances, the liquid ammonia storage tank enters the liquid ammonia vaporizer through the first inlet and switching outlet of the ammonia source switching mechanism, supplying liquid ammonia raw material to the liquid ammonia vaporizer. The liquid ammonia vaporizer vaporizes the liquid ammonia into gaseous ammonia. When the pressure of the liquid ammonia storage tank is too high, the ammonia source switching mechanism switches to the second inlet and switching outlet to receive gaseous ammonia supplied by the gas phase outlet of the liquid ammonia storage tank, ensuring the stability of the liquid ammonia storage tank pressure. The formaldehyde feeding device delivers formaldehyde solution to the formaldehyde inlet of the microchannel reactor through the formaldehyde outlet. Formaldehyde and gaseous ammonia fully react in the microchannel reactor to generate hexamethylenetetramine reaction liquid, which is output through the reaction liquid outlet, realizing the continuous and stable production of hexamethylenetetramine and significantly improving production efficiency and product quality.

[0037] An ammonia filter is installed between the outlet of the liquid ammonia vaporizer and the ammonia inlet of the microchannel reactor to remove impurities from the gaseous ammonia and improve the purity of the reaction raw materials. The formaldehyde feeding device includes a formaldehyde storage tank, a formaldehyde feed pump, a mass flow meter, and a formaldehyde flow regulating valve, which realizes the metering and stable delivery of formaldehyde solution.

[0038] In summary, this invention effectively solves the technical problems of unstable ammonia supply, low reaction control precision, and poor production continuity in traditional urotropine production by switching between dual ammonia sources and controlling flow, thus achieving efficient, continuous, and stable production of urotropine. It has significant technological advancements and practical value. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the continuous production equipment for hexamethylenetetramine according to this utility model. Detailed Implementation

[0040] To make the contents of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0041] like Figure 1 As shown, a continuous production apparatus for hexamethylenetetramine includes:

[0042] A liquid ammonia storage tank, which is equipped with a liquid ammonia outlet 1 and a gas phase outlet 3;

[0043] The ammonia source switching mechanism has a first inlet connected to the liquid ammonia outlet 1 of the liquid ammonia storage tank, a second inlet connected to the gas phase outlet 3 of the liquid ammonia storage tank, and a switching outlet.

[0044] The liquid ammonia vaporizer 2 has its inlet connected to the switching outlet of the ammonia source switching mechanism, and the liquid ammonia vaporizer 2 is equipped with an ammonia outlet.

[0045] Formaldehyde feeding device 5, formaldehyde feeding device 5 is equipped with a formaldehyde outlet;

[0046] The microchannel reactor 6 is equipped with an ammonia inlet, a formaldehyde inlet, and a reaction liquid outlet. The ammonia inlet is connected to the ammonia outlet of the liquid ammonia vaporizer 2, the formaldehyde inlet is connected to the formaldehyde outlet of the formaldehyde feeding device 5, and the reaction liquid outlet is suitable for outputting hexamethylenetetramine reaction liquid.

[0047] In this embodiment, as Figure 1 As shown, under normal circumstances, the liquid ammonia storage tank enters the liquid ammonia vaporizer 2 through the first inlet and switching outlet of the ammonia source switching mechanism, supplying liquid ammonia raw material to the liquid ammonia vaporizer 2. The liquid ammonia vaporizer 2 vaporizes the liquid ammonia into gaseous ammonia. When the pressure of the liquid ammonia storage tank is too high, the ammonia source switching mechanism switches to the second inlet and switching outlet to receive gaseous ammonia provided by the gas phase outlet 3 of the liquid ammonia storage tank, ensuring the stability of the liquid ammonia storage tank pressure. The formaldehyde feeding device 5 delivers the formaldehyde solution to the formaldehyde inlet of the microchannel reactor 6 through the formaldehyde outlet. The formaldehyde and gaseous ammonia react fully in the microchannel reactor 6 to generate hexamethylenetetramine reaction solution, which is output through the reaction solution outlet.

[0048] Specifically, such as Figure 1 As shown, the ammonia source switching mechanism is a three-way switching valve 4.

[0049] In this embodiment, as Figure 1 As shown, the first inlet is connected to the liquid ammonia outlet 1 of the liquid ammonia storage tank via a pipeline, the second inlet is connected to the gas phase outlet 3 of the liquid ammonia storage tank via a pipeline, and the switching outlet is connected to the inlet of the liquid ammonia vaporizer 2 via a pipeline. When the first inlet and the switching outlet are connected, liquid ammonia flows from the liquid ammonia outlet 1 into the liquid ammonia vaporizer 2 through the first inlet and the switching outlet. When the second inlet and the switching outlet are connected, gaseous ammonia flows from the gas phase outlet 3 into the liquid ammonia vaporizer 2 through the second inlet and the switching outlet.

[0050] Specifically, such as Figure 1 As shown, the continuous production equipment for hexamethylenetetramine also includes an ammonia filter 7, which is located between the ammonia outlet of the liquid ammonia vaporizer and the ammonia inlet of the microchannel reactor 6.

[0051] In this embodiment, as Figure 1As shown, when the gaseous ammonia generated by the liquid ammonia vaporizer 2 flows through the ammonia filter 7, the solid particles and impurities in the gaseous ammonia are intercepted by the filter element, and the filtered clean gaseous ammonia enters the microchannel reactor 6 from the outlet of the ammonia filter 7.

[0052] Specifically, such as Figure 1 As shown, the formaldehyde supply device 5 includes:

[0053] Formaldehyde storage tank, the formaldehyde storage tank is equipped with a formaldehyde storage tank outlet;

[0054] The formaldehyde feed pump has its inlet connected to the outlet of the formaldehyde storage tank and also has an outlet.

[0055] Specifically, such as Figure 1 As shown, the continuous production equipment for hexamethylenetetramine also includes a formaldehyde mass flow meter 51, a formaldehyde flow regulating valve 52, an ammonia flow meter, an ammonia flow regulating valve, and a controller.

[0056] The formaldehyde mass flow meter 51 is installed on the pipeline between the formaldehyde outlet of the formaldehyde feeding device 5 and the formaldehyde inlet of the microchannel reactor 6. The flow meter inlet of the formaldehyde mass flow meter 51 is connected to the pump outlet of the formaldehyde feed pump.

[0057] The formaldehyde flow regulating valve 52 is located between the formaldehyde mass flow meter 51 and the formaldehyde inlet of the microchannel reactor 6. The valve inlet of the formaldehyde flow regulating valve 52 is connected to the flow meter outlet of the formaldehyde mass flow meter 51, and the valve outlet of the formaldehyde flow regulating valve 52 is connected to the formaldehyde inlet of the microchannel reactor 6.

[0058] An ammonia flow meter is installed on the pipeline between the ammonia outlet of the liquid ammonia vaporizer 2 and the ammonia inlet of the microchannel reactor 6.

[0059] The ammonia flow regulating valve is located between the switching outlet of the ammonia source switching mechanism and the inlet of the liquid ammonia vaporizer 2.

[0060] The controller is electrically connected to the formaldehyde mass flow meter 51, the formaldehyde flow regulating valve 52, the ammonia flow meter, and the ammonia flow regulating valve, respectively. The controller is adapted to adjust the opening of the formaldehyde flow regulating valve 52 and the ammonia flow regulating valve according to the formaldehyde flow signal from the formaldehyde mass flow meter 51 and the ammonia flow signal from the ammonia flow meter, so as to adjust the feed ratio of formaldehyde and ammonia.

[0061] In this embodiment, as Figure 1 As shown, the molar ratio of formaldehyde to ammonia in the feed is controlled between 1:1.1 and 1.3.

[0062] The formaldehyde in this embodiment is dilute formaldehyde. In some embodiments, the formaldehyde feed pump can be a diaphragm pump or a screw pump.

[0063] Specifically, such as Figure 1 As shown, the liquid ammonia vaporizer 2 is equipped with a heat exchange medium inlet and a heat exchange medium outlet. The reaction liquid outlet of the microchannel reactor 6 is connected to the heat exchange medium inlet of the liquid ammonia vaporizer 2, and the heat exchange medium outlet is suitable for discharging the hexamethylenetetramine reaction liquid.

[0064] In this embodiment, as Figure 1 As shown, the hexamethylenetetramine reaction solution enters the liquid ammonia vaporizer 2 through the reaction solution outlet of the microchannel reactor 6 to provide vaporization heat for the liquid ammonia, and flows out from the heat exchange medium outlet of the liquid ammonia vaporizer 2 after heat exchange.

[0065] Specifically, such as Figure 1 As shown, the continuous production equipment for hexamethylenetetramine also includes a reaction liquid heat exchanger 8, a second circulating water supply pipe 16, and a second circulating water return pipe 17.

[0066] The reaction liquid heat exchanger 8 is located on the downstream pipeline of the heat exchange medium outlet of the liquid ammonia vaporizer 2. The reaction liquid heat exchanger 8 is provided with a cooler inlet, a cooler outlet, a cooling medium inlet, and a cooling medium outlet.

[0067] The inlet of the reaction liquid heat exchanger 8 is connected to the outlet of the liquid ammonia vaporizer 2. The second circulating water supply pipe 16 is connected to the inlet of the cooling medium of the reaction liquid heat exchanger 8, and the second circulating water return pipe 17 is connected to the outlet of the cooling medium of the reaction liquid heat exchanger 8.

[0068] In this embodiment, as Figure 1 As shown, circulating water enters the reaction liquid heat exchanger 8 through the second circulating water supply pipe 16 to remove the heat from the hexamethylenetetramine reaction liquid, and the heated return water flows out through the second circulating water return pipe 17.

[0069] Specifically, such as Figure 1 As shown, the continuous production equipment for hexamethylenetetramine also includes a reaction liquid temperature sensor, a cooling medium flow regulating valve, and a controller;

[0070] The reaction liquid temperature sensor is installed on the downstream pipe of the cooler outlet of the reaction liquid heat exchanger 8. The reaction liquid temperature sensor is suitable for detecting the temperature of the reaction liquid and sending a temperature signal.

[0071] A cooling medium flow regulating valve is installed on the second circulating water supply pipe 16;

[0072] The controller is electrically connected to the reaction liquid temperature sensor and the cooling medium flow regulating valve, respectively. The controller is adapted to adjust the opening of the cooling medium flow regulating valve according to the temperature signal of the reaction liquid temperature sensor, so as to control the reaction liquid temperature within the range of 50-70°C.

[0073] Specifically, such as Figure 1As shown, the continuous production equipment for urotropine also includes a near-infrared analyzer and a pH sensor;

[0074] The near-infrared analyzer and pH sensor are respectively installed on the downstream pipeline of the reaction liquid outlet of the microchannel reactor 6. The near-infrared analyzer detects the formaldehyde content of the reaction liquid in the pipeline of the reaction liquid outlet in real time and sends out a formaldehyde content signal. The pH sensor is suitable for detecting the pH value of the reaction liquid in the pipeline of the reaction liquid outlet and sending out a pH value signal.

[0075] The controller is connected to a near-infrared analyzer and a pH sensor respectively. The controller is suitable for adjusting the opening of the ammonia flow regulating valve according to the formaldehyde content signal of the near-infrared analyzer to prevent excessive ammonia input. It is also suitable for controlling the alarm to issue an alarm signal when the pH value signal received from the pH sensor exceeds the preset range.

[0076] In this embodiment, both the near-infrared analyzer and the pH sensor are existing technologies, and will not be described in detail here.

[0077] Specifically, the continuous production equipment for urotropine also includes a pressure sensor and a controller. The pressure sensor is installed on the liquid ammonia storage tank and is adapted to detect the pressure in the tank and send a pressure signal. The controller is electrically connected to both the pressure sensor and the three-way switching valve 4. The controller is adapted to adjust the switching state of the three-way switching valve 4 according to the pressure signal from the pressure sensor. When the pressure sensor detects that the pressure in the liquid ammonia storage tank is too high, the controller controls the three-way switching valve 4 to switch from connecting the first inlet to the switching outlet to connecting the second inlet to the switching outlet.

[0078] In this embodiment, the channel width of the microchannel reactor 6 is no greater than 1 mm, and the reaction residence time is less than 30 seconds. The formaldehyde solution concentration is 15%-30%.

[0079] In this embodiment, as Figure 1As shown, liquid ammonia outlet 1 is selected for use first. The first inlet of the three-way switching valve 4 is connected to the switching outlet. Liquid ammonia flows out from liquid ammonia outlet 1, passes through the switching outlet of the three-way switching valve 4 and the ammonia flow regulating valve, and enters the liquid ammonia vaporizer 2. The liquid ammonia vaporizer 2 heats the liquid ammonia with the hexamethylenetetramine reaction solution input from the reaction liquid outlet of the microchannel reactor 6, completely vaporizing the liquid ammonia into gaseous ammonia. When the controller detects that the pressure in the liquid ammonia storage tank is too high through the pressure sensor, the controller controls the three-way switching valve 4 to switch to the second inlet and the switching outlet. The gaseous ammonia in the gas phase outlet 3 enters the second inlet of the three-way switching valve 4 through the gas phase outlet, and flows out from the switching outlet of the three-way switching valve 4, passes through the ammonia flow regulating valve, and enters the liquid ammonia vaporizer 2, ensuring the stability of the liquid ammonia storage tank pressure. The gaseous ammonia generated by the liquid ammonia vaporizer 2 is filtered by the ammonia filter 7 to remove impurities, and the flow rate is measured by the ammonia flow meter. The clean gaseous ammonia enters the ammonia inlet of the microchannel reactor 6. Meanwhile, the formaldehyde solution in the formaldehyde feeding device 5 has its flow rate measured by the formaldehyde mass flow meter 51, and then its flow rate is adjusted by the formaldehyde flow regulating valve 52 before entering the formaldehyde inlet of the microchannel reactor 6.

[0080] The controller dynamically adjusts the opening of the formaldehyde flow regulating valve 52 and the ammonia flow regulating valve based on the flow signals from the formaldehyde mass flow meter 51 and the ammonia flow meter, controlling the molar ratio of formaldehyde to ammonia between 1:1.1 and 1.3. Gaseous ammonia and formaldehyde solution react in the microchannels within the microchannel reactor 6 to produce hexamethylenetetramine, with a reaction residence time of less than 30 seconds.

[0081] The generated hexamethylenetetramine reaction solution flows out of the reaction solution outlet of the microchannel reactor 6 and into the heat exchange medium inlet of the liquid ammonia vaporizer 2. It then flows out of the heat exchange medium outlet of the liquid ammonia vaporizer 2 and into the cooler inlet of the reaction solution heat exchange cooler 8. Cooling water supplied through the second circulating water supply pipe 16 in the reaction solution heat exchange cooler 8 removes heat from the reaction solution. The controller adjusts the opening of the cooling medium flow regulating valve based on the temperature signal from the reaction solution temperature sensor, maintaining the reaction solution temperature between 50°C and 70°C. The cooled hexamethylenetetramine reaction solution flows out from the cooler outlet of the reaction solution heat exchange cooler 8 and enters the subsequent separation and purification process, completing the continuous production process of hexamethylenetetramine.

[0082] Meanwhile, the near-infrared analyzer monitors the formaldehyde value of the reaction solution in real time, and the controller adjusts the ammonia flow regulating valve according to the near-infrared analyzer signal to prevent excessive ammonia flow.

[0083] The controller can be either a PLC or a DCS.

[0084] In addition, this embodiment also includes an ammonia oil recovery tank, into which recyclable and separable materials filtered by the ammonia filter 7 enter.

[0085] During initial startup, the controller switches the three-way switching valve 4 to connect with the gas phase outlet 3, directly feeding the initially generated gaseous ammonia from the liquid ammonia storage tank into the microchannel reactor 6. Simultaneously, the formaldehyde feeding device is activated to begin the reaction, and the generated hot hexamethylenetetramine reaction liquid circulates through the liquid ammonia vaporizer 2 according to the normal process, thus preheating the vaporizer 2. When the temperature of the liquid ammonia vaporizer 2 reaches the stable operating requirement, the controller smoothly switches the three-way switching valve 4 to connect with the liquid ammonia outlet 1, allowing the liquid ammonia to enter the preheated vaporizer 2 and vaporize using the heat of the hexamethylenetetramine reaction liquid, enabling the equipment to smoothly enter a self-sustaining stable operating state.

[0086] In addition, the physical properties of liquid ammonia can be utilized for self-starting. Given the extremely low vaporization temperature of liquid ammonia (-33.4°C at standard atmospheric pressure), it exhibits a strong tendency to vaporize at room temperature. Therefore, during the initial startup phase, the initial ambient heat around the liquid ammonia vaporizer 2 and its piping can be used to naturally vaporize a small amount of liquid ammonia entering from the liquid ammonia outlet 1 inside the vaporizer 2. This initial generation of gaseous ammonia initiates the initial reaction with formaldehyde within the microchannel reactor 6. Once the reaction begins and generates hexamethylenetetramine reaction liquid, this reaction liquid serves as the primary heat source, improving the heat exchange efficiency of the liquid ammonia vaporizer 2 through the loop.

[0087] The specific embodiments described above further illustrate the technical problems, technical solutions, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A continuous production equipment for urotropine, characterized in that, include: A liquid ammonia storage tank, wherein the liquid ammonia storage tank is provided with a liquid ammonia outlet (1) and a gas phase outlet (3); The ammonia source switching mechanism has a first inlet connected to the liquid ammonia outlet (1) and a second inlet connected to the gas phase outlet (3). The ammonia source switching mechanism is provided with a switching outlet. A liquid ammonia vaporizer (2) is provided with an ammonia outlet. The inlet of the liquid ammonia vaporizer (2) is connected to the switching outlet of the ammonia source switching mechanism. A formaldehyde feeding device (5) is provided with a formaldehyde outlet; The microchannel reactor (6) is provided with an ammonia inlet, a formaldehyde inlet and a reaction liquid outlet. The ammonia inlet is connected to the ammonia outlet of the liquid ammonia vaporizer (2), the formaldehyde inlet is connected to the formaldehyde outlet of the formaldehyde feeding device (5), and the reaction liquid outlet is suitable for outputting hexamethylenetetramine reaction liquid.

2. The continuous production equipment for urotropine according to claim 1, characterized in that, The ammonia source switching mechanism is a three-way switching valve (4).

3. The continuous production equipment for urotropine according to claim 1, characterized in that, It also includes an ammonia filter (7), which is disposed between the ammonia outlet of the liquid ammonia vaporizer (2) and the ammonia inlet of the microchannel reactor (6).

4. The continuous production equipment for urotropine according to claim 1, characterized in that, It also includes a formaldehyde mass flow meter (51), a formaldehyde flow regulating valve (52), an ammonia flow meter, an ammonia flow regulating valve, and a controller; The formaldehyde mass flow meter (51) is installed on the pipeline between the formaldehyde outlet of the formaldehyde feeding device (5) and the formaldehyde inlet of the microchannel reactor (6). The formaldehyde mass flow meter (51) is adapted to detect the flow rate in the pipeline and send a formaldehyde flow signal. The formaldehyde flow regulating valve (52) is located between the formaldehyde mass flow meter (51) and the formaldehyde inlet of the microchannel reactor (6); The ammonia flow meter is installed on the pipeline between the ammonia outlet of the liquid ammonia vaporizer (2) and the ammonia inlet of the microchannel reactor (6); The ammonia flow regulating valve is located between the switching outlet of the ammonia source switching mechanism and the inlet of the liquid ammonia vaporizer (2), and the ammonia flow meter is adapted to detect the ammonia flow and send an ammonia flow signal. The controller is connected to the formaldehyde mass flow meter (51), the formaldehyde flow regulating valve (52), the ammonia flow meter and the ammonia flow regulating valve respectively. The controller is adapted to adjust the opening of the formaldehyde flow regulating valve (52) and the ammonia flow regulating valve according to the formaldehyde flow signal of the formaldehyde mass flow meter (51) and the ammonia flow signal of the ammonia flow meter, so as to adjust the feed ratio of formaldehyde and ammonia.

5. The continuous production equipment for urotropine according to claim 1, characterized in that, The liquid ammonia vaporizer (2) is provided with a heat exchange medium inlet and a heat exchange medium outlet; The reaction liquid outlet of the microchannel reactor (6) is connected to the heat exchange medium inlet of the liquid ammonia vaporizer (2), and the heat exchange medium outlet is suitable for outputting hexamethylenetetramine reaction liquid.

6. The continuous production equipment for hexamethylenetetramine according to claim 5, characterized in that, It also includes a reaction liquid heat exchanger (8), a second circulating water supply pipe (16), and a second circulating water return pipe (17); The reaction liquid heat exchange cooler (8) is located on the downstream pipeline of the heat exchange medium outlet of the liquid ammonia vaporizer (2). The reaction liquid heat exchange cooler (8) is provided with a cooler inlet, a cooler outlet, a cooling medium inlet and a cooling medium outlet. The inlet of the heat exchanger (8) is connected to the outlet of the heat exchange medium of the liquid ammonia vaporizer (2), and the outlet of the heat exchanger is suitable for outputting hexamethylenetetramine reaction solution. The second circulating water supply pipe (16) is connected to the cooling medium inlet of the reaction liquid heat exchanger (8), and the second circulating water return pipe (17) is connected to the cooling medium outlet of the reaction liquid heat exchanger (8).

7. The continuous production equipment for urotropine according to claim 6, characterized in that, It also includes a reaction liquid temperature sensor, a cooling medium flow regulating valve, and a controller; The reaction liquid temperature sensor is installed on the downstream pipe of the cooler outlet of the reaction liquid heat exchanger (8). The reaction liquid temperature sensor is adapted to detect the reaction liquid temperature and send a temperature signal. The cooling medium flow regulating valve is installed on the second circulating water supply pipe (16); The controller is connected to the reaction liquid temperature sensor and the cooling medium flow regulating valve respectively, and the controller is adapted to adjust the opening of the cooling medium flow regulating valve according to the temperature signal of the reaction liquid temperature sensor.

8. The continuous production equipment for urotropine according to claim 4, characterized in that, It also includes a near-infrared analyzer and a pH sensor; The near-infrared analyzer and pH sensor are respectively installed on the downstream pipeline of the reaction liquid outlet of the microchannel reactor (6). The near-infrared analyzer detects the formaldehyde content of the reaction liquid in the pipeline of the reaction liquid outlet in real time and sends out a formaldehyde content signal. The pH sensor is suitable for detecting the pH value of the reaction liquid in the pipeline of the reaction liquid outlet and sending out a pH value signal. The controller is connected to the near-infrared analyzer and the pH sensor respectively. The controller is adapted to adjust the opening of the ammonia flow regulating valve according to the formaldehyde content signal of the near-infrared analyzer, and is adapted to control the alarm to issue an alarm signal when the pH value signal emitted by the pH sensor exceeds the preset range.

9. The continuous production equipment for urotropine according to claim 2, characterized in that, It also includes pressure sensors and controllers; The pressure sensor is installed on the liquid ammonia storage tank, and the pressure sensor is adapted to detect the pressure of the liquid ammonia storage tank and send a pressure signal. The controller is connected to the pressure sensor and the three-way switching valve (4) respectively. The controller is adapted to control the three-way switching valve (4) to switch between connecting the switching outlet with the first inlet and connecting the switching outlet with the second inlet according to the pressure signal of the pressure sensor.

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