Coupling batching reaction system for preparing cyclic carbonate by urea method

Abstract

The utility model relates to the technical field of preparation of cyclic carbonate by a urea method, and aims to solve the problems that the existing urea raw material generally adopts solid particles, the dissolution speed is low, a large amount of heat needs to be consumed for heating to promote dissolution, and the energy consumption is increased. The utility model provides a coupling ingredient reaction system for preparing cyclic carbonate by a urea method, which comprises a reaction kettle, a first propylene glycol feeding pipe, a urea liquid inlet pipe, a spiral mixer and a feeding pipe, the propylene glycol feeding pipe is communicated with the feeding end of the spiral mixer; the urea liquid inlet pipe is communicated with the feeding end of the spiral mixer; the spiral mixer is communicated with the reaction kettle through the feeding pipe; according to the utility model, the urea melt liquid is directly used as a raw material to participate in the reaction, and does not need to be prepared into particles to be dissolved in propylene glycol, so that a large amount of energy consumption required when urea solid particles and propylene glycol are independently dissolved can be saved.

Description

Technical Field

[0001] This utility model relates to the field of urea method for preparing cyclic carbonates, and more specifically, to a urea method for preparing cyclic carbonates coupled with a batching reaction system. Background Technology

[0002] The principle of cyclic carbonate preparation via the urea process is as follows: two adjacent -NH4+ groups in urea... - The group combines with the oxygen atom of the epoxide to form a double hydrogen bond, which is beneficial to the activation of the epoxide. Under the action of a catalyst, the activated epoxide undergoes ring opening. At the same time, the -NH in urea... - Activated CO2 inserts into the open-ring epoxy ring to form an intermediate product, which then undergoes intramolecular ring closure to form a cyclic carbonate.

[0003] Urea is one of the raw materials for the preparation of cyclic carbonates by the urea method. The conventional method is to use solid granular urea, dissolve it in propylene glycol, and then feed it into the reactor. This process is complicated, and the solid particles dissolve slowly. During the process, the temperature needs to be increased to promote dissolution, which leads to increased energy consumption. For example, the patent with publication number CN104059047A discloses a continuous reaction process for the synthesis of cyclic carbonates from urea. Urea, polyol and catalyst are continuously fed into a raw material mixer in proportion. For the convenience of transportation and addition, the urea is in the form of solid particles.

[0004] Based on the above description, there is an urgent need for a urea-based coupled feedstock reaction system for preparing cyclic carbonates. Utility Model Content

[0005] The purpose of this invention is to provide a urea-based cyclic carbonate preparation coupled reaction system, which aims to solve the technical problem that existing urea raw materials usually use solid particles, which have a slow dissolution rate and require a large amount of heat to promote dissolution, resulting in increased energy consumption.

[0006] The embodiments of this utility model are achieved through the following technical solutions:

[0007] A urea-based coupled batching reaction system for preparing cyclic carbonates includes a reaction vessel, a first propylene glycol feed pipe, a urea inlet pipe, a spiral mixer, and a feeding pipe; the propylene glycol feed pipe is connected to the inlet end of the spiral mixer; the urea inlet pipe is connected to the inlet end of the spiral mixer; the spiral mixer is connected to the reaction vessel via the feeding pipe.

[0008] Preferably, the device also includes a preheating tank and a second propylene glycol feed; the second propylene glycol feed is connected to the preheating tank; the preheating tank is connected to the feed end of the screw mixer through the first propylene glycol feed pipe.

[0009] Preferably, the feed pipe is provided with a heat exchange jacket.

[0010] Preferably, the heat exchange jacket is connected to multiple heat exchange systems.

[0011] Preferably, the heat exchange system includes a first heat exchange tower, a first induced draft fan, and an exhaust fan; the first induced draft fan is connected to the first heat exchange tower; the first heat exchange tower is connected to the heat exchange jacket; and the exhaust fan is connected to the heat exchange jacket.

[0012] Preferably, the device also includes a second heat exchange tower; the spiral mixer is provided with an insulated shell; the second heat exchange tower is connected to the insulated shell; and the insulated shell is connected to the first induced draft fan.

[0013] Preferably, a second induced draft fan is connected between the second heat exchange tower and the insulation shell.

[0014] The technical solution of this utility model embodiment has at least the following advantages and beneficial effects:

[0015] This invention uses molten urea directly as a raw material in the reaction, eliminating the need to prepare it into granules and then dissolve it in propylene glycol. This saves a significant amount of energy compared to dissolving solid urea granules and propylene glycol separately. Specifically, molten urea is introduced into a spiral mixer through a urea inlet pipe, and propylene glycol is introduced into the spiral mixer through a first propylene glycol inlet pipe. The two are then premixed by the spiral mixer, and the mixed and dissolved material is then fed into the reaction vessel through a feeding pipe. This method achieves high dissolution efficiency and eliminates the need for additional heat to promote dissolution. Attached Figure Description

[0016] 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.

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

[0018] Icons: 1-Reaction vessel, 2-First propylene glycol feed pipe, 3-Urea inlet pipe, 4-Screw mixer, 5-Feeding pipe, 6-Preheating tank, 7-Second propylene glycol feed, 8-Heat exchange system, 81-First heat exchange tower, 82-First induced draft fan, 83-Exhaust fan, 84-Second heat exchange tower, 9-Second induced draft fan. Detailed Implementation

[0019] Example 1

[0020] Please see Figure 1 The present invention provides the following technical solution: a urea method for preparing cyclic carbonates coupled with a batching reaction system, applicable to the batching reaction system for preparing cyclic carbonates using the urea method.

[0021] Specifically, such as Figure 1 As shown, a urea-based cyclic carbonate preparation coupled batching reaction system includes a reactor 1, a first propylene glycol feed pipe 2, a urea inlet pipe 3, a spiral mixer 4, and a feeding pipe 5; the propylene glycol feed pipe is connected to the inlet end of the spiral mixer 4; the urea inlet pipe 3 is connected to the inlet end of the spiral mixer 4; the spiral mixer 4 is connected to the reactor 1 through the feeding pipe 5.

[0022] In this embodiment, by using molten urea directly as a raw material to participate in the reaction, it is not necessary to prepare it into particles and then dissolve it in propylene glycol, which can save a lot of energy consumption required to dissolve solid urea particles and propylene glycol separately. Specifically, molten urea is introduced into the spiral mixer 4 through the urea inlet pipe 3, and propylene glycol is introduced into the spiral mixer 4 through the first propylene glycol inlet pipe 2. The two are then premixed by the spiral mixer 4, and the mixed and dissolved material is sent into the reaction vessel 1 through the feed pipe 5 for reaction. The dissolution efficiency is high and there is no need to consume a lot of heat for heating to promote dissolution.

[0023] Specifically, such as Figure 1 As shown, it also includes a preheating tank 6 and a second propylene glycol feed 7; the second propylene glycol feed 7 is connected to the preheating tank 6; the preheating tank 6 is connected to the feed end of the screw mixer 4 through the first propylene glycol feed pipe 2.

[0024] The preheating tank 6 can preheat the propylene glycol before it enters the screw mixer 4, which can prevent local condensation and agglomeration of propylene glycol in the early stage of mixing with urea melt after it enters the screw mixer 4, which could cause blockage of the screw mixer 4 and the subsequent feeding pipe 5. This also makes it easier to flexibly adjust the material ratio of urea melt and propylene glycol according to production needs.

[0025] Specifically, such as Figure 1 As shown, the 5 sets of feed pipes are equipped with heat exchange jackets.

[0026] In this embodiment, the heat exchange jacket is a commonly used insulation jacket for pipe bodies in the art, and a sealed heat exchange annular gap is left between it and the feed pipe 5.

[0027] Specifically, such as Figure 1 As shown, the heat exchange jacket is connected to multiple heat exchange systems 8. The heat exchange system 8 includes a first heat exchange tower 81, a first induced draft fan 82, and an exhaust fan 83; the first induced draft fan 82 is connected to the first heat exchange tower 81; the first heat exchange tower 81 is connected to the heat exchange jacket; and the exhaust fan 83 is connected to the heat exchange jacket.

[0028] In this embodiment, hot air or steam is provided by the first heat exchange tower 81. The air outlet pipe or gas outlet pipe of the first heat exchange tower 81 is connected to the heat exchange annular gap near the feed end of the feeding pipe 5, while the gas outlet pipe connected to the exhaust fan 83 is located in the heat exchange annular gap near the feed end of the feeding pipe 5. Since the mixed material has a certain conveying distance, multiple sets of heat exchange systems 8 can be set at intervals in the feeding pipe 5.

[0029] Specifically, such as Figure 1 As shown, it also includes a second heat exchange tower 84; the spiral mixer 4 is provided with an insulation shell; the second heat exchange tower 84 is connected to the insulation shell; the insulation shell is connected to the first induced draft fan 82. A second induced draft fan 9 is connected between the second heat exchange tower 84 and the insulation shell.

[0030] In this embodiment, to meet the needs of continuous production, a medium-to-large-sized spiral mixer 4 is used for mixing. To ensure the temperature during mixing, an insulating shell is further provided outside the spiral mixer 4. A sealing ring gap is left between the insulating shell and the outer wall of the spiral mixer 4. Hot air or steam is provided for insulation through a second heat exchange tower 84. The insulating hot air or steam in the sealing ring gap is further drawn into the first heat exchange tower 81 through a connecting pipe for further heating. This is used for pipeline conveying heat tracing, which can reduce energy consumption, avoid pipeline blockage, and improve material conveying efficiency.

[0031] 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 urea-based cyclic carbonate preparation coupled reaction system, comprising a reaction vessel (1), characterized in that: It also includes a first propylene glycol feed pipe (2), a urea inlet pipe (3), a spiral mixer (4), and a feeding pipe (5); the propylene glycol feed pipe is connected to the feed end of the spiral mixer (4); the urea inlet pipe (3) is connected to the feed end of the spiral mixer (4); the spiral mixer (4) is connected to the reactor (1) through the feeding pipe (5).

2. The urea-based cyclic carbonate preparation coupled reaction system according to claim 1, characterized in that: It also includes a preheating tank (6) and a second propylene glycol feed (7); the second propylene glycol feed (7) is connected to the preheating tank (6); the preheating tank (6) is connected to the feed end of the spiral mixer (4) through the first propylene glycol feed pipe (2).

3. The urea-based cyclic carbonate preparation coupled reaction system according to claim 1, characterized in that: The feed pipe (5) is fitted with a heat exchange jacket.

4. The urea-based cyclic carbonate preparation coupled reaction system according to claim 3, characterized in that: The heat exchange jacket is connected to multiple heat exchange systems (8).

5. The urea-based cyclic carbonate preparation coupled reaction system according to claim 4, characterized in that: The heat exchange system (8) includes a first heat exchange tower (81), a first induced draft fan (82) and an exhaust fan (83); the first induced draft fan (82) is connected to the first heat exchange tower (81); the first heat exchange tower (81) is connected to the heat exchange jacket; and the exhaust fan (83) is connected to the heat exchange jacket.

6. The urea-based cyclic carbonate preparation coupled reaction system according to claim 5, characterized in that: It also includes a second heat exchange tower (84); the spiral mixer (4) is provided with an insulation shell; the second heat exchange tower (84) is connected to the insulation shell; the insulation shell is connected to the first induced draft fan (82).

7. The urea-based cyclic carbonate preparation coupled reaction system according to claim 6, characterized in that: A second induced draft fan (9) is connected between the second heat exchange tower (84) and the insulation shell.

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