A high-efficiency reactor suitable for preparing cyclic carbonate by urea process

Abstract

The present invention relates to the field of cyclic carbonate preparation devices, and specifically discloses a high-efficiency reactor suitable for preparing cyclic carbonate by urea method, which solves the technical problem that the pipeline is too long and ammonia in the material is difficult to remove in the current process of preparing cyclic carbonate by urea method. It includes: a reactor body, which includes a plurality of sub-reactors arranged at intervals in the vertical direction; a circulation unit, which is arranged one by one with the sub-reactors, and is provided with a circulation pipeline connected to the bottom and top of the sub-reactors, and a nozzle is arranged at the top pipeline opening of the circulation pipeline; a material transfer unit, including a transfer pipe, which is connected to the circulation pipeline of two adjacent reactors; a guide unit, which is arranged near the top pipeline opening of the circulation pipeline, and the guide unit includes a guide plate arranged at an angle at the output end of the circulation pipeline; a baffle, which is located in the reactor body and is arranged above each sub-reactor, and the baffle separates the cavity enclosed between the sub-reactor and the reactor body from the upper space to increase the ammonia removal effect.

Description

Technical Field

[0001] The invention relates to the technical field of cyclic carbonate preparation devices, and in particular to a high-efficiency reactor suitable for preparing cyclic carbonate by a urea process. Background Art

[0002] As an important chemical raw material, urea is widely used in many fields. The use of urea method to synthesize cyclic carbonates can not only effectively promote the recycling of resources and improve resource utilization efficiency, but also significantly reduce production costs, which is of great significance to promoting the development of green chemistry and environmental protection.

[0003] At present, in the process of preparing cyclic carbonate by urea method, it is usually necessary to use multiple kettle reactors connected by pipelines. This method is more common in industrial production, because through the series operation of multiple reactors, the reaction conditions can be better controlled, the efficiency of the reaction and the purity of the product can be improved. For example, patent CN104059047A discloses a continuous reaction process for synthesizing cyclic carbonate from urea, which regulates the liquid level in each kettle reactor by accurately controlling the circulation extraction ratio, thereby effectively avoiding the energy consumption and unstable product quality caused by frequent heating and cooling during intermittent operation of a single kettle. This method not only improves the efficiency of energy utilization, but also significantly improves the quality consistency of the product.

[0004] First of all, the above-mentioned device inevitably requires the use of more pipeline settings. In the process of transferring materials from one reactor to another, the residence time and temperature changes in the pipeline may trigger side reactions, resulting in an increase in by-products, which in turn affects the purity and yield of the final product. Secondly, the flow of materials in the pipeline may make it difficult for ammonia to overflow in the pipeline, especially when the pipeline is long or the design is unreasonable. The accumulation of ammonia will not only affect the efficiency of the reaction, but may also bring safety hazards. Furthermore, the complexity of multi-tank reactors is also reflected in equipment maintenance and operation control. The connection of multiple reactors and pipelines increases the complexity of the system, requiring more sophisticated control strategies and higher operating skills. This not only increases the initial investment and operating costs of the equipment, but may also increase the difficulty of maintenance and failure rate in long-term operation.

[0005] In addition, in the existing urea process for synthesizing cyclic carbonates, a large amount of ammonia byproduct is produced during the reaction. In order to ensure the continuity and safety of production, vacuuming measures are usually taken to remove the ammonia, but some ammonia will still remain in the material and is difficult to completely remove. This situation not only affects the quality of the final product, but may also bring safety risks. Summary of the invention

[0006] The purpose of the present invention is to provide a high-efficiency reactor suitable for preparing cyclic carbonates by the urea method, so as to solve the technical problems in the current process of preparing cyclic carbonates by the urea method, that is, the pipeline is too long and the residual ammonia mixed in the material is difficult to remove.

[0007] The present invention provides a high-efficiency reactor suitable for preparing cyclic carbonate by urea method, comprising: a reactor body, which includes a plurality of sub-reactors arranged at intervals in the vertical direction, and the reactor body also includes a first feed pipe, a first discharge pipe and a gas phase pipe arranged thereon; a circulation unit, which is arranged one-to-one with the sub-reactors and is provided with a circulation pipeline connected to the bottom and the top of the sub-reactors, and a nozzle is arranged at the top pipeline opening of the circulation pipeline; a material transfer unit, which includes a transfer pipe, and along the vertical direction, one end of the transfer pipe is connected to the circulation pipeline of the previous sub-reactor, and the other end is connected to the circulation pipeline of the next sub-reactor; a guide unit, which is arranged near the top pipeline opening of the circulation pipeline, and the guide unit includes a guide plate, and the guide plate is arranged at an angle at the output end of the circulation pipeline; a plurality of baffles are provided, which are located in the reactor body and above each of the sub-reactors, and the baffle separates the cavity enclosed between the sub-reactor and the reactor body from the upper space.

[0008] According to one embodiment of the present invention, the circulation pipeline includes a first pipeline, a second pipeline and a third pipeline, the first pipeline is connected to the second pipeline through a pump, the second pipeline is connected to the third pipeline through a heat exchanger, a nozzle is provided at the end of the third pipeline, and the first pipeline is connected to the bottom of the sub-reactor.

[0009] According to one embodiment of the present invention, one end of the transfer pipe is connected to the third pipe of the previous reactor, and the other end is connected to the third pipe of the next reactor.

[0010] According to one embodiment of the present invention, the guide plate is a perforated plate.

[0011] According to one embodiment of the present invention, the guide plate is a curved plate.

[0012] According to one embodiment of the present invention, the guide plates are provided with multiple layers at intervals along the vertical direction, and the multiple layers of guide plates enclose a flow channel for the material to flow.

[0013] According to one embodiment of the present invention, the method further comprises a stirring device at least partially disposed in the reaction kettle.

[0014] According to one embodiment of the present invention, the stirring device includes an arc-shaped stirring paddle, and the curvature of the arc-shaped stirring paddle matches the curvature of the bottom of the sub-reactor.

[0015] According to one embodiment of the present invention, the gas phase pipe is connected to a vacuum system via a condenser.

[0016] According to one embodiment of the present invention, the reactor body and each of the sub-reactors are provided with a heating jacket and a heating coil.

[0017] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0018] (1) The present invention introduces a circulation unit, which extracts material from the bottom of the reactor and sprays it again from the top of the reactor. During this process, ammonia is fully released and can be effectively removed by the exhaust device, ensuring the high quality of the product and the overall safety of the system.

[0019] (2) The present invention is equipped with a flow guide unit. When the material is sprayed onto the unit, the time for the material to flow back to the reaction system can be effectively shortened, while increasing the residence time of the material in the upper space, thereby more effectively promoting the release of ammonia.

[0020] (3) The present invention provides a structure of multiple sub-reactors in one reactor, which facilitates the extraction of ammonia gas. Only one condenser needs to be provided at the top of the tower. This arrangement greatly reduces the number of pipelines in the entire system and avoids the increase of side reactions caused by the long residence time of the material in the pipeline.

[0021] (4) The present invention provides a heat exchanger to ensure the cyclic heating of the material during the reflux process, thereby achieving an efficient and stable organic reaction process and ensuring the smooth progress of the reaction.

[0022] (5) The present invention adopts an advanced stirring device, which greatly improves the mixing effect of the materials, not only speeds up the reaction rate, but also significantly improves the quality of the final product.

[0023] (6) The present invention provides a baffle plate extending into the sub-reactor inside the reactor body. The baffle plate is provided above each sub-reactor to separate the cavity enclosed between the sub-reactor and the reactor body from the space above, thereby ensuring that the material does not flow directly into the reactor body due to the overflow effect, but is instead transported from the upper sub-reactor to the lower sub-reactor layer by layer in the vertical direction through the transfer pipe for reaction, thereby ensuring the ammonia discharge effect of the material and the adequacy of the reaction.

[0024] (7) The present invention has reasonable design, simple structure and good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 This is a schematic structural diagram of a high-efficiency reactor suitable for preparing cyclic carbonates by the urea process provided in Example 1 of the present invention.

[0027] Figure 2 This is a schematic diagram of the structure of a high-efficiency reactor suitable for preparing cyclic carbonates by the urea process provided in Example 2 of the present invention.

[0028] Reference numerals:

[0029] 100, reactor body; 110, sub-reactor; 120, first feed pipe; 130, gas phase pipe; 140, condenser; 111, heating coil; 112, heating jacket;

[0030] 210, first pipeline; 220, second pipeline; 230, third pipeline; 240, pump; 250, heat exchanger; 260, valve;

[0031] 310, guide plate;

[0032] 400, transfer pipe;

[0033] M, stirring motor; 510, stirring shaft; 520, arc-shaped stirring paddle;

[0034] 600, baffle;

[0035] 700. Nitrogen inflation tube. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0037] Example 1

[0038] Embodiment 1 of the present invention provides a high-efficiency reactor suitable for preparing cyclic carbonates by urea process, so as to reduce pipelines and promote the overflow of ammonia in the material in the reactor.

[0039] See also Figure 1The embodiment of the present invention provides a high-efficiency reactor suitable for preparing cyclic carbonate by urea method, comprising: a reactor body 100, which includes a plurality of sub-reactors 110 arranged at intervals in the vertical direction, the reactor body 100 also includes a first feed pipe 120, a first discharge pipe and a gas phase pipe 130 arranged thereon, the first feed pipe 120 is arranged at the top of the reactor body 100, the first discharge pipe is arranged at the bottom of the reactor body 100, and the gas phase pipe 130 is arranged at the top of the reactor body 100, which is used for input and output of materials and extraction of ammonia generated during the reaction process; a circulation unit, which is arranged in a one-to-one correspondence with the sub-reactors 110, and is provided with a circulation pipeline connected to the bottom and top of the sub-reactors 110, and a nozzle is provided at the top of the circulation pipeline. The unit extracts materials from the bottom of the reactor and sprays them again from the top of the reactor. In this process, ammonia is fully released, which is convenient for effective removal through the exhaust device, ensuring the high quality of the product and the overall safety of the system; a material transfer unit, including a transfer pipe 400, along the vertical direction, the transfer pipe One end of 400 is connected to the circulation pipeline of the previous sub-reactor 110, and the other end is connected to the circulation pipeline of the next sub-reactor 110, so that the material extracted from the previous reactor is passed into the next reactor to realize the transfer of the material; the guide unit is arranged near the top pipeline opening of the circulation pipeline, and the guide unit includes a guide plate 310, and the guide plate 310 is arranged at an angle at the output end of the circulation pipeline. When the material is sprayed onto the unit, the time for the material to flow back to the reaction system can be effectively shortened, and at the same time, the material in the upper The residence time in the upper space of the reactor body 100 is shortened, thereby more effectively promoting the release of ammonia; a plurality of baffles 600 are provided, which are located in the reactor body 100 and are arranged above each of the sub-reactors 110. The baffles 600 separate the cavity enclosed between the sub-reactor 110 and the reactor body 100 from the upper space to prevent the material from flowing downward during the spraying process. In this embodiment, the bottom of the baffle 600 is located inside the sub-reactor 110. In this embodiment, the baffle 600 is an annular plate connected to the reactor body 100.

[0040] In this embodiment, the circulation pipeline includes a first pipeline 210, a second pipeline 220 and a third pipeline 230. The first pipeline 210 is connected to the second pipeline 220 through a pump 240, and the second pipeline 220 is connected to the third pipeline 230 through a heat exchanger 250, ensuring the circulation heating of the material during the reflux process, realizing an efficient and stable organic reaction process, and ensuring the smooth progress of the reaction. A nozzle is provided at the end of the third pipeline 230, and the first pipeline 210 is connected to the bottom of the sub-reactor 110. In this embodiment, valves 260 are respectively provided on the first pipeline 210, the second pipeline 220 and the third pipeline 230.

[0041] In this embodiment, the output end of the third pipe 230 is set at an angle to the guide plate 310, and the nozzle at the end of the third pipe 230 is close to the guide plate 310 to ensure that the sprayed material acts on the guide unit and the material flows down along the guide plate 310 to increase the reflux time of the material.

[0042] In this embodiment, one end of the transfer pipe 400 is connected to the third pipeline 230 of the previous reactor, and the other end is connected to the third pipeline 230 of the next reactor to transfer the material of the previous reactor into the next reactor. In this embodiment, the transfer pipe 400 is provided with a valve 260.

[0043] In this embodiment, the guide plate 310 is a perforated plate, so that part of the material can flow back into the reaction system of the sub-reactor 110 along the inner holes of the guide plate 310 .

[0044] In this embodiment, the guide plate 310 is an arc-shaped plate to increase the surface area of ​​the guide plate 310 and increase the downflow time of the material.

[0045] In this embodiment, the guide plates 310 are arranged in multiple layers at intervals along the vertical direction, and the multiple layers of guide plates 310 enclose a flow channel for the flow of materials, so that the time of the materials in the reflux process is further increased by the staggered or spaced arrangement of the multiple layers of guide plates 310 to facilitate the overflow of ammonia.

[0046] In this embodiment, a stirring device is also included that is at least partially disposed in the reactor to stir the reaction materials, thereby increasing the reaction effect of the reactants and the overflow of ammonia. In this embodiment, the stirring device includes a stirring motor M, a stirring shaft 510, and a plurality of arc-shaped stirring paddles 520 arranged at intervals along the extension direction of the stirring shaft 510. The arc-shaped stirring paddles 520 are arranged corresponding to the sub-reactor 110. In this embodiment, an arc-shaped stirring paddle 520 corresponding to the reactor body 100 is also provided, which is arranged close to the bottom of the reactor body 100. In this embodiment, the stirring shaft 510 is coaxially arranged with the reactor body 100.

[0047] In this embodiment, the curvature of the arc-shaped stirring paddle 520 matches the curvature of the bottom of the sub-reactor 110 and the bottom of the reactor body 100. Stirring can ensure the uniform distribution of the reactants in the reactor, make the reactants fully contact, prevent local concentrations from being too high or too low, ensure the stable progress of the reaction, and thus improve the reaction rate and conversion rate. The curvature of the arc-shaped stirring paddle matches the bottom of the sub-reactor 110, and a thin film can be formed at the bottom of each sub-reactor 110. This film can increase the contact area between the reactants and the catalyst, thereby improving the mass transfer efficiency, helping to accelerate the diffusion and mass transfer process of the reactants, and further improving the reaction rate. Furthermore, the film formed by stirring can effectively disperse heat and avoid local overheating. Through uniform stirring, the reaction temperature can be better controlled to ensure that the reaction is carried out within an appropriate temperature range. In addition, the formation of this film also helps to quickly release ammonia and reduce the accumulation of ammonia in the reaction system, thereby reducing safety risks and improving product purity.

[0048] In this embodiment, the gas phase pipe 130 is connected to the vacuum system via the condenser 140, which helps to remove the by-product ammonia in the reaction process and make the product quality more reliable.

[0049] In this embodiment, the reactor body 100 and each of the sub-reactors 110 are provided with a heating jacket 112 and a heating coil 111 to control the reaction temperature and ensure that the reaction is carried out within a suitable temperature range.

[0050] The following is a detailed description of the use of the high-efficiency reactor suitable for preparing cyclic carbonate by urea process of the present invention:

[0051] When in use, the material is extracted from the bottom of the sub-reactor 110 by the pump 240 and circulated and heated through the heat exchanger 250. A portion of the heated material is sprayed from the top of the sub-reactor 110 toward the flow guide unit through the third pipeline 230. During the spraying process, the material flows back to the reaction system after passing through the flow guide unit. In this process, ammonia can be fully released. Another portion of the material is transported from the transfer pipe 400 to the next sub-reactor 110. The released ammonia is effectively removed by the exhaust device, ensuring the safety of the system and the high quality of the product.

[0052] Example 2

[0053] Embodiment 2 of the present invention provides a high-efficiency reactor suitable for preparing cyclic carbonates by urea process, so as to reduce pipelines and promote the overflow of ammonia in the material in the reactor.

[0054] See also Figure 2The high-efficiency reactor suitable for preparing cyclic carbonate by urea process provided in the embodiment of the present invention is different from that in Embodiment 1 only in that, in the present embodiment, it also includes a nitrogen blowing pipe 700, which is arranged at the bottom of each sub-reactor 110 to blow nitrogen into the bottom of the sub-reactor 110. The bubbling effect formed helps to accelerate the escape of ammonia, so as to further increase the mixing effect of the reactants and the overflow effect of ammonia. The released ammonia is effectively removed by the exhaust device, thereby ensuring the safety of the system and the high quality of the product.

[0055] The embodiments of the present invention have at least the following advantages:

[0056] (8) The present invention introduces a circulation unit, which extracts material from the bottom of the reactor and sprays it again from the top of the reactor. During this process, ammonia is fully released and can be effectively removed by the exhaust device, ensuring the high quality of the product and the overall safety of the system.

[0057] (9) The present invention is equipped with a flow guide unit. When the material is sprayed onto the unit, the time for the material to flow back to the reaction system can be effectively shortened, while increasing the residence time of the material in the upper space, thereby more effectively promoting the release of ammonia.

[0058] (10) The present invention arranges a plurality of sub-reactors in one reactor, thereby facilitating the extraction of ammonia gas. Only one condenser needs to be arranged at the top of the tower. This arrangement greatly reduces the number of pipelines in the entire system and avoids the increase of side reactions caused by the long residence time of the material in the pipeline.

[0059] (11) The present invention provides a heat exchanger to ensure the cyclic heating of the material during the reflux process, thereby achieving an efficient and stable organic reaction process and ensuring the smooth progress of the reaction.

[0060] (12) The present invention adopts an advanced stirring device, which greatly improves the mixing effect of the materials, not only speeds up the reaction rate, but also significantly improves the quality of the final product.

[0061] (13) The present invention provides a baffle plate extending into the sub-reactor inside the reactor body. The baffle plate is provided above each sub-reactor to separate the cavity enclosed between the sub-reactor and the reactor body from the space above, thereby ensuring that the material does not flow directly into the reactor body due to the overflow effect, but is transferred from the upper sub-reactor to the lower sub-reactor layer by layer in the vertical direction through the transfer pipe for reaction, thereby ensuring the ammonia discharge effect of the material and the adequacy of the reaction.

[0062] (14) The present invention has reasonable design, simple structure and good practicality.

[0063] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-efficiency reactor suitable for preparing cyclic carbonate by urea process, characterized in that: include: A reactor body, which includes a plurality of sub-reactors spaced apart in a vertical direction, and the reactor body also includes a first feed pipe, a first discharge pipe and a gas phase pipe arranged thereon; A circulation unit is arranged one-to-one with the sub-reactors, and is provided with a circulation pipeline connected to the bottom and top of the sub-reactors, and a nozzle is provided at the pipeline opening at the top of the circulation pipeline; The material transfer unit comprises a transfer pipe, one end of which is connected to the circulation pipe of the previous sub-reactor and the other end of which is connected to the circulation pipe of the next sub-reactor in the vertical direction; A flow guide unit is arranged near the top pipe opening of the circulation pipe, and the flow guide unit comprises a flow guide plate, and the flow guide plate is arranged at an angle at the output end of the circulation pipe; A plurality of baffles are provided, which are located in the reactor body and above each of the sub-reactors, and the baffles separate the cavity enclosed between the sub-reactor and the reactor body from the space above.

2. The high-efficiency reactor suitable for preparing cyclic carbonate by urea process according to claim 1, characterized in that: The circulation pipeline includes a first pipeline, a second pipeline and a third pipeline, the first pipeline is connected to the second pipeline through a pump, the second pipeline is connected to the third pipeline through a heat exchanger, a nozzle is provided at the end of the third pipeline, and the first pipeline is connected to the bottom of the sub-reactor.

3. The high-efficiency reactor suitable for preparing cyclic carbonate by urea process according to claim 2, characterized in that: One end of the transfer pipe is connected to the third pipe of the previous reactor, and the other end is connected to the third pipe of the next reactor.

4. The high-efficiency reactor suitable for preparing cyclic carbonate by urea process according to any one of claims 1 to 3, characterized in that: The guide plate is a perforated plate.

5. The high-efficiency reactor suitable for preparing cyclic carbonate by urea process according to any one of claims 1 to 3, characterized in that: The guide plate is an arc-shaped plate.

6. The high-efficiency reactor suitable for preparing cyclic carbonate by urea process according to any one of claims 1 to 3, characterized in that: The guide plates are provided with multiple layers at intervals along the vertical direction, and the multiple layers of guide plates surround a flow channel for the material to flow.

7. The high-efficiency reactor suitable for preparing cyclic carbonate by urea process according to any one of claims 1 to 3, characterized in that: It also includes a stirring device which is at least partially arranged in the reaction kettle.

8. The high-efficiency reactor suitable for preparing cyclic carbonate by urea process according to claim 7, characterized in that: The stirring device comprises an arc-shaped stirring paddle, the curvature of which matches the curvature of the bottom of the sub-reactor.

9. The high-efficiency reactor suitable for preparing cyclic carbonate by urea process according to any one of claims 1 to 3, characterized in that: The gas phase pipe is connected to a vacuum system through a condenser.

10. The high-efficiency reactor suitable for preparing cyclic carbonate by urea process according to any one of claims 1 to 3, characterized in that: The reactor body and each of the sub-reactors are provided with a heating jacket and a heating coil.

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