Dissolving device for preparing cyclic carbonate by urea method

Abstract

The utility model relates to the field of cyclic carbonate preparation devices, particularly discloses a dissolving device for preparing cyclic carbonate by a urea method, and solves the technical problems that ammonia gas and air cannot be effectively separated and explosion is easy to generate in the use process of the existing urea dissolving device. The device comprises a premixing tank; the urea feeding pipe comprises a first pipe orifice located outside the premixing tank and a second pipe orifice located inside the premixing tank, and the second pipe orifice is a horn mouth; the nitrogen supplementing pipe is arranged on the urea feeding pipe at an angle; the tail gas outlet pipe is arranged on the urea feeding pipe in an angle mode, and the tail gas outlet pipe is higher than the nitrogen supplementing pipe; wherein under the condition that liquid is supplemented in the premixing tank, the height of the second pipe opening is not higher than the height of the liquid level, the nitrogen supplementing pipe is arranged close to the liquid level, and the height of the lowest point of the nitrogen supplementing pipe is not lower than the height of the liquid level. According to the device, air cannot be brought into the kettle body when urea is fed, so that explosion is avoided.

Description

Technical Field

[0001] This utility model relates to the technical field of cyclic carbonate preparation apparatus, and more specifically, to a dissolution apparatus for preparing cyclic carbonates using the urea method. Background Technology

[0002] In the urea process for preparing cyclic carbonates, urea is typically dissolved in a solvent to form a solution for subsequent cyclic carbonate synthesis. This step helps improve the solubility and reactivity of urea; commonly used solvents include water and alcohols (such as methanol and ethanol).

[0003] However, existing urea dissolving devices generate ammonia gas when urea is added to the diol during the urea dissolving process. Ammonia is a flammable and explosive gas with a narrow explosion limit range (approximately 15% to 28% by volume). In addition, a certain amount of air is introduced during the feeding process. If ammonia gas remains in the reactor and comes into contact with air, there is a potential explosion risk. In a closed reactor, ammonia gas mixes with air, especially under high temperature and high pressure conditions, which can easily lead to an explosion.

[0004] In existing technologies, the common method is to extract the gas inside the reactor along with the ammonia to reduce the accumulation of ammonia. However, this method cannot effectively separate ammonia from air, and therefore cannot completely avoid the risk of explosion. The extracted gas still contains a large amount of ammonia, which not only wastes raw materials but may also pollute the environment. Utility Model Content

[0005] The purpose of this invention is to provide a dissolving device for the preparation of cyclic carbonates using the urea method, thereby solving the technical problem that current urea dissolving devices cannot effectively separate ammonia and air, which can easily lead to explosions.

[0006] This invention provides a dissolving apparatus for preparing cyclic carbonates using the urea method, comprising: a premixing tank; a urea feed pipe, including a first port located outside the premixing tank and a second port located inside the premixing tank, the second port being a flared opening; a nitrogen replenishment pipe, connected to the urea feed pipe and angled relative to it; and a tail gas outlet pipe, connected to the urea feed pipe and angled relative to it, wherein the vertical height of the connection point between the tail gas outlet pipe and the urea feed pipe is higher than the vertical height of the connection point between the nitrogen replenishment pipe and the urea feed pipe; wherein, when liquid is replenished in the premixing tank, the height of the second port is not higher than the liquid level, the nitrogen replenishment pipe is positioned close to the liquid level, and the lowest point of the nitrogen replenishment pipe is not lower than the liquid level.

[0007] According to one embodiment of the present invention, the nitrogen replenishment pipe includes a third port located outside the premixing tank and a fourth port located inside the premixing tank. The nitrogen replenishment pipe is connected to the urea feed pipe through the fourth port. In the vertical direction, the height of the third port is higher than the height of the fourth port.

[0008] According to one embodiment of the present invention, the nitrogen replenishment pipe is set at an angle of 40° to 50° to the urea feed pipe.

[0009] According to one embodiment of the present invention, the exhaust gas outlet pipe includes a fifth port and a sixth port. The exhaust gas outlet pipe is connected to the urea feed pipe through the sixth port. In the vertical direction, the height of the fifth port is higher than the height of the sixth port.

[0010] According to one embodiment of the present invention, the exhaust gas outlet pipe is set at an angle of 40° to 50° to the urea inlet pipe.

[0011] According to one embodiment of the present invention, the premix tank is equipped with a stirring device.

[0012] According to one embodiment of the present invention, the urea feed pipe, the nitrogen replenishment pipe and the exhaust gas outlet pipe are equipped with valves.

[0013] The technical solution of this utility model has at least the following advantages and beneficial effects:

[0014] (1) In this utility model, the second port of the urea feed pipe is located below the liquid surface. When urea enters the liquid below the urea feed pipe, the air remains in the urea feed pipe. The ammonia gas that may be generated by the decomposition of urea will be above the liquid surface outside the feed pipe and will not come into contact with the air in the feed pipe, thereby avoiding an explosion.

[0015] (2) This utility model addresses the problem that a certain amount of ammonia may be generated on the liquid surface inside the urea feed pipe. It sets up a nitrogen replenishment pipe and a tail gas outlet pipe connected to the urea feed pipe, which can continuously replenish nitrogen into the feed pipe and then continuously discharge the mixed gas in the urea feed pipe.

[0016] (3) This utility model has a reasonable design, simple structure and good practicality. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the dissolving apparatus for preparing cyclic carbonates using the urea method provided in Embodiment 1 of this utility model;

[0019] Figure 2 A schematic diagram of the dissolving apparatus for preparing cyclic carbonates using the urea method provided in Embodiment 2 of this utility model;

[0020] icon:

[0021] 100. Premixing tank;

[0022] 200. Urea feed pipe;

[0023] 300. Nitrogen replenishment tube;

[0024] 400. Exhaust gas outlet pipe;

[0025] 500. Stirring device;

[0026] 600. Heating jacket. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Example 1

[0029] This invention provides a dissolving apparatus for preparing cyclic carbonates using the urea method, to prevent the apparatus from exploding during the reaction process.

[0030] Please see Figure 1 The present invention provides a dissolving apparatus for the preparation of cyclic carbonates using the urea method.

[0031] Includes: a premixing tank 100, a container for dissolving urea, made of stainless steel; and a urea feed pipe 200, including a first inlet located outside the premixing tank 100 and a second inlet located inside the premixing tank 100. The second inlet is a flared opening. When urea enters below the liquid through the urea feed pipe 200, air remains in the urea feed pipe 200. Ammonia gas that may be generated during urea decomposition will remain above the liquid surface outside the feed pipe and will not come into contact with the air in the feed pipe, thus avoiding the generation of ammonia gas. The flared opening facilitates urea feeding and prevents pipe blockage. A nitrogen replenishment pipe 300 connects to the urea feed pipe 200 and is angled relative to it. The nitrogen replenishment pipe 300 replenishes nitrogen into the feed pipe, continuously discharging the mixed gas from the urea feed pipe 200 and reducing ammonia accumulation. In this embodiment, the nitrogen replenishment pipe 300 and the urea feed pipe 200 are set at a 90° angle. A tail gas outlet pipe 400 connects to the urea feed pipe 200. The urea inlet pipe 200 is connected to the nitrogen supply pipe 300 at a 90° angle. The tail gas outlet pipe 400 is used to discharge the mixed gas in the urea inlet pipe 200. In this embodiment, the tail gas outlet pipe 400 and the urea inlet pipe 200 are set at a 90° angle. The vertical height of the connection point between the tail gas outlet pipe 400 and the urea inlet pipe 200 is higher than the vertical height of the connection point between the nitrogen supply pipe 300 and the urea inlet pipe 200. Liquid is added to the premix tank 100. Under these conditions, the height of the second inlet is not higher than the liquid level. The nitrogen replenishment pipe 300 is positioned close to the liquid level, and the lowest point of the nitrogen replenishment pipe 300 is not lower than the liquid level to ensure that the urea feed directly enters the solution. By placing the second inlet of the urea feed pipe 200 below the liquid level, ammonia is prevented from contacting air, reducing the risk of explosion. The design of the nitrogen replenishment pipe 300 and the tail gas outlet pipe 400 effectively manages the gas in the feed pipe and reduces the accumulation of ammonia.

[0032] In this embodiment, the premixing tank 100 is equipped with a stirring device 500. The stirring device 500 can ensure the uniform mixing of urea and solvent and improve the dissolution rate. In this embodiment, the stirring device 500 includes a stirring motor, a stirring shaft and a stirring paddle. The stirring motor is located outside the premixing tank 100 and extends into the premixing tank 100 through the stirring shaft to connect to the stirring paddle. The stirring paddle is located near the bottom of the premixing tank 100.

[0033] In this embodiment, valves are provided in the urea feed pipe 200, nitrogen replenishment pipe 300 and tail gas outlet pipe 400. The valves can control the opening and closing of each pipe to ensure the smooth entry and exit of gas and the safe operation of the system.

[0034] In this embodiment, the premix tank 100 is equipped with a material discharge pipe, and a valve is provided on the material discharge pipe.

[0035] In this embodiment, the premix tank 100 is equipped with a heating jacket 600 and a cooling coil to regulate the reaction temperature inside the premix tank 100.

[0036] The following is a detailed description of the use of the dissolving apparatus for preparing cyclic carbonates using the urea method in Embodiment 1 of this utility model:

[0037] Solvent is introduced into the premixing tank 100, and the stirring device 500 is started to ensure that the solvent is evenly distributed and that the height of the second inlet of the urea feed pipe 200 is below the height of the solvent liquid. Urea is introduced into the premixing tank 100 through the urea feed pipe 200, and the urea is added slowly to avoid local overheating caused by adding a large amount at once. The heating jacket 600 is turned on to raise the temperature to the predetermined value. Stirring continues until the urea is completely dissolved and a uniform solution is formed. Nitrogen is introduced into the nitrogen replenishment pipe 300 at regular intervals so that the mixed gas is discharged from the tail gas outlet pipe 400.

[0038] Example 2

[0039] This invention provides a dissolving apparatus for preparing cyclic carbonates using the urea method, to prevent the apparatus from exploding during the reaction process.

[0040] Please see Figure 2 The urea method for preparing cyclic carbonates provided in Embodiment 2 of this utility model differs from Embodiment 1 only in that, in this embodiment, the nitrogen replenishment pipe 300 is set at 40° to 50° with the urea feed pipe 200, and the tail gas outlet pipe 400 is set at 40° to 50° with the urea feed pipe 200.

[0041] Specifically, in this embodiment, the nitrogen replenishment pipe 300 is set at a 45° angle to the urea feed pipe 200, and the exhaust gas outlet pipe 400 is set at a 45° angle to the urea feed pipe 200.

[0042] In this embodiment, the nitrogen replenishment pipe 300 includes a third port located outside the premixing tank 100 and a fourth port located inside the premixing tank 100. The nitrogen replenishment pipe 300 is connected to the urea feed pipe 200 through the fourth port. In the vertical direction, the height of the third port is higher than the height of the fourth port. The nitrogen inlet direction is set at a 45° angle to the liquid surface to ensure that the nitrogen can act on the mixed gas above the liquid surface, promote the passage of the mixed gas, and reduce the possibility of gas backflow.

[0043] In this embodiment, the exhaust gas outlet pipe 400 includes a fifth port and a sixth port. The exhaust gas outlet pipe 400 is connected to the urea feed pipe 200 through the sixth port. In the vertical direction, the height of the fifth port is higher than the height of the sixth port to ensure that the exhaust gas is smoothly discharged from the feed pipe.

[0044] The embodiments of this utility model have at least the following advantages:

[0045] (1) In this utility model, the second port of the urea feed pipe is located below the liquid surface. When urea enters the liquid below the urea feed pipe, the air remains in the urea feed pipe. The ammonia gas that may be generated by the decomposition of urea will be above the liquid surface outside the feed pipe and will not come into contact with the air in the feed pipe, thereby avoiding an explosion.

[0046] (2) This utility model addresses the problem that a certain amount of ammonia may be generated on the liquid surface inside the urea feed pipe. It sets up a nitrogen replenishment pipe and a tail gas outlet pipe connected to the urea feed pipe, which can replenish nitrogen into the feed pipe and then continuously discharge the mixed gas in the urea feed pipe.

[0047] (3) This utility model has a reasonable design, simple structure and good practicality.

[0048] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A dissolving apparatus for preparing cyclic carbonates using the urea method, characterized in that, include: Premix tank; The urea feed pipe includes a first port located outside the premixing tank and a second port located inside the premixing tank, the second port being a flared opening; A nitrogen replenishment pipe is connected to the urea feed pipe, and is angled relative to the urea feed pipe. The exhaust gas outlet pipe is connected to the urea feed pipe, and the angle is set at the urea feed pipe. The vertical height of the connection point between the exhaust gas outlet pipe and the urea feed pipe is higher than the vertical height of the connection point between the nitrogen replenishment pipe and the urea feed pipe. When liquid is added to the premix tank, the height of the second inlet is not higher than the liquid level, the nitrogen replenishment pipe is located close to the liquid level, and the lowest point of the nitrogen replenishment pipe is not lower than the liquid level.

2. The dissolving apparatus for preparing cyclic carbonates using the urea method according to claim 1, characterized in that, The nitrogen replenishment pipe includes a third port located outside the premixing tank and a fourth port located inside the premixing tank. The nitrogen replenishment pipe is connected to the urea feed pipe through the fourth port. In the vertical direction, the height of the third port is higher than the height of the fourth port.

3. The dissolving apparatus for preparing cyclic carbonates using the urea method according to claim 2, characterized in that, The nitrogen replenishment pipe is positioned at a 40°–50° angle to the urea feed pipe.

4. The dissolving apparatus for preparing cyclic carbonates by the urea method according to any one of claims 1 to 3, characterized in that, The exhaust gas outlet pipe includes a fifth port and a sixth port. The exhaust gas outlet pipe is connected to the urea feed pipe through the sixth port. In the vertical direction, the height of the fifth port is higher than the height of the sixth port.

5. The dissolving apparatus for preparing cyclic carbonates using the urea method according to claim 4, characterized in that, The exhaust gas outlet pipe is set at an angle of 40° to 50° to the urea inlet pipe.

6. The dissolving apparatus for preparing cyclic carbonates by the urea method according to any one of claims 1 to 3, characterized in that, The premix tank is equipped with a stirring device.

7. The dissolving apparatus for preparing cyclic carbonates by the urea method according to any one of claims 1 to 3, characterized in that, The urea feed pipe, the nitrogen replenishment pipe, and the exhaust gas outlet pipe are equipped with valves.

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