Recycling system for cyclic carbonate catalyst prepared by urea method

Abstract

The utility model provides a catalyst recovery system for preparing cyclic carbonate by a urea method, relates to the technical field of fine chemical engineering, and solves the technical problem that a gas-phase outlet easily carries a solid-phase catalyst to enter a rectifying tower to block the rectifying tower when the catalyst is separated and recovered by an evaporator in the prior art. The device comprises a separation tank used for separating a catalyst in a gas phase, the separation tank is provided with a cyclone separation layer used for separating a liquid-solid phase and a solid phase in the gas phase, and the cyclone separation layer is composed of a plurality of groups of parallel cyclone separators and baffles used for filling gaps among the cyclone separators. According to the utility model, the separation efficiency of the catalyst is improved, the effective recovery of the catalyst is ensured, and the energy consumption of the system is reduced; the service life of the system is prolonged, the maintenance cost is reduced, the reliable operation of the system is ensured, the pressure drop loss is small, and the production continuity and stability are improved.

Description

Technical Field

[0001] This utility model relates to the field of fine chemical technology, and more specifically, to a catalyst recovery system for the preparation of cyclic carbonates using the urea method. Background Technology

[0002] Cyclic carbonates (ethylene carbonate, propylene carbonate, glycerol carbonate, etc.) are a new type of "green" organic compound with wide applications and considerable attention both domestically and internationally. Specifically, they can be applied to the extraction and separation of mixtures, organic synthesis (synthesis of polycarbonate resins, phenolic resins, and biodegradable medical polymer materials), high-energy-density battery electrolytes, cosmetic additives, and supercritical fluid separation technology.

[0003] The process of preparing cyclic carbonates from urea is an important chemical conversion. To improve reaction selectivity and yield, a catalyst is typically used to facilitate this conversion. The selection of the catalyst and its effective recovery and reuse are crucial factors for the industrialization of this process. For solid catalysts, the most direct method is to separate the catalyst from the reaction mixture by filtration. Effective separation and recovery of the catalyst are essential for reducing production costs, minimizing environmental pollution, and improving the overall economic efficiency of the process. Furthermore, optimizing catalyst recovery methods can extend catalyst lifespan and further enhance the sustainability of the entire production process. Therefore, researching and developing efficient and economical catalyst recovery technologies is a vital aspect of promoting the industrialization of the urea-to-cyclic carbonate process.

[0004] Therefore, the method for recovering catalysts from the reaction of urea and polyols to prepare cyclic carbonates, as proposed in patent CN110339867A, uses the mixture after the reaction of urea and polyols as the separation raw material. Without filtration, the mixture directly enters the evaporator to separate the light components; the remaining catalyst and heavy components are then calcined at high temperature, achieving a catalyst recovery rate greater than 99.0%. This recovery method is economically efficient, suitable for large-scale industrial application, and has the advantage of low catalyst loss. However, the vapor outlet of the evaporator directly enters the distillation column, and the vapor outlet carries some solid catalyst, which can cause blockage in the distillation column. Utility Model Content

[0005] The purpose of this invention is to provide a catalyst recovery system for the urea process for preparing cyclic carbonates, in order to solve the technical problem that existing catalysts are separated and recovered by evaporators, and the gas phase outlet easily carries solid catalysts into the distillation column, causing blockage of the distillation column.

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

[0007] A urea process for preparing cyclic carbonate catalyst recovery system includes a separation tank for separating the catalyst in the gas phase. The separation tank is provided with a cyclone separation layer for separating the liquid-solid and solid phases in the gas phase. The cyclone separation layer consists of several sets of parallel cyclone separators and baffles for filling the gaps between the cyclone separators.

[0008] Preferably, the cyclone separator includes a cylinder, an air inlet at the lower end of the cylinder and an air outlet at the upper end, and the cylinder is also provided with a guide plate for spiraling airflow.

[0009] Preferably, the cross-sectional area of ​​the air inlet is larger than the cross-sectional area of ​​the air outlet, and the air inlet is configured as a regular hexagon.

[0010] Preferably, the separator is further provided with a gas phase inlet below the cyclone separation layer, a gas phase outlet and a liquid-solid phase outlet respectively located at the top and bottom of the separator.

[0011] Preferably, the air inlet is further provided with a separation cylinder for spirally guiding and outputting the solid and liquid phases, and the outlet height of the separation cylinder is lower than the height of the gas phase inlet.

[0012] Preferably, the air outlet is further provided with a rectifier for collecting and rectifying air, and a gap is provided between the rectifier and the separation cylinder for the passage of spiral airflow.

[0013] Preferably, the separator is further provided with a baffle layer above the cyclone separation layer to further block the passage of liquid and solid phases in the gas phase.

[0014] Preferably, the separation tank is further provided with a flushing pipeline above the baffle layer.

[0015] In this technical solution, the separator tank serves as the main body of the entire system, responsible for separating the catalyst in the gas phase and ensuring its effective recovery. By incorporating a cyclone separation layer and a baffle layer, multi-stage separation is achieved, improving separation efficiency and effectiveness. The cyclone separation layer consists of several sets of parallel cyclone separators, increasing the separation area and improving efficiency. Baffles fill the gaps between the cyclone separators, preventing airflow short-circuiting and ensuring uniform airflow distribution, further enhancing the separation effect. The air inlet is located at the lower end of the tank, with a cross-sectional area larger than the outlet, and is hexagonal, contributing to uniform airflow distribution and improved separation efficiency. The air outlet is located at the upper end of the tank, with a cross-sectional area smaller than the inlet, facilitating the formation of high-speed airflow and improving separation effectiveness. A guide plate is used for spiral flow guidance, directing the airflow to form vortices, enhancing centrifugal force, and improving separation efficiency. The separator cylinder is used for spiral flow guidance and output of the separated solid and liquid phases, ensuring smooth discharge and preventing blockage. The gas phase inlet is located below the separator tank, ensuring airflow enters from the bottom, passes through the cyclone separation layer, and exits from the top. The gas phase outlet is located at the top of the separator to ensure that the separated gas phase exits from the top, reducing the catalyst content in the gas phase. The liquid-solid phase outlet is located at the bottom of the separator to ensure that the separated liquid and solid phases exit from the bottom, facilitating collection and treatment. A rectifier hood is used for gas collection and rectification, ensuring uniform airflow distribution, reducing airflow turbulence, and improving separation efficiency. A baffle layer is located above the cyclone separation layer to further block the passage of liquid and solid phases in the gas phase, improving separation efficiency. The combination of the baffle layer and the cyclone separation layer achieves multi-stage separation, improving the thoroughness and efficiency of separation. A flushing line is located above the baffle layer, allowing for regular cleaning of the separator's interior, ensuring long-term stable operation of the system, preventing the accumulation of catalyst and impurities, and extending the system's service life.

[0016] The urea-based cyclic carbonate catalyst recovery system achieves the following key benefits through multi-stage separation, a high-efficiency cyclone separator, a rational design layout, and thorough cleaning and maintenance: Multi-stage separation and the cyclone separator design significantly improve catalyst separation efficiency, ensuring effective catalyst recovery. A well-designed airflow and separation structure reduce system energy consumption and improve economic efficiency. Flushing pipelines and the multi-stage separation design extend system lifespan and reduce maintenance costs. Multi-stage separation and cleaning / maintenance measures ensure reliable system operation, improving production continuity and stability. Highly efficient catalyst recovery reduces catalyst waste and environmental pollution, aligning with sustainable development requirements.

[0017] The technical solution of this utility model embodiment has at least the following advantages and beneficial effects:

[0018] 1. This invention improves the separation efficiency of the catalyst, ensures the effective recovery of the catalyst, and reduces the energy consumption of the system;

[0019] 2. This utility model extends the service life of the system, reduces maintenance costs, ensures the reliable operation of the system, and improves the continuity and stability of production. Attached Figure Description

[0020] 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.

[0021] Figure 1 This is a cross-sectional structural schematic diagram of the urea method for preparing cyclic carbonate catalyst recovery system provided in Embodiment 1 of this utility model;

[0022] Figure 2 This is a top-view cross-sectional view of the urea-method cyclic carbonate catalyst recovery system provided in Embodiment 1 of this utility model.

[0023] Figure 3 A schematic diagram of the working principle of the cyclone separator in the urea method for preparing cyclic carbonate catalyst recovery system provided in Embodiment 2 of this utility model;

[0024] Icons: 1. Separator tank; 2. Baffle layer; 3. Cyclone separation layer; 31. Baffle; 4. Cyclone separator; 41. Air inlet; 42. Separator cylinder; 43. Air outlet; 44. Smooth shroud; 45. Drain plate; 46. Cylinder body; 11. Gas phase inlet; 12. Gas phase outlet; 13. Liquid-solid phase outlet; 5. Flushing pipeline. Detailed Implementation

[0025] 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.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0027] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0028] In the description of this utility model, it should be noted that if terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" appear to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0029] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0030] Example 1

[0031] A urea process for preparing cyclic carbonate catalyst recovery system includes a separation tank 1 for separating the catalyst in the gas phase. The separation tank 1 is provided with a cyclone separation layer 3 for separating the liquid-solid and solid phases in the gas phase. The cyclone separation layer 3 consists of several sets of parallel cyclone separators 4 and baffles 31 for filling the gaps between the cyclone separators 4.

[0032] In this embodiment, the separation tank 1 is further provided with a gas phase inlet 11 lower than the cyclone separation layer 3, a gas phase outlet 12 and a liquid-solid phase outlet 13 respectively provided at the top and bottom of the separation tank 1.

[0033] In this embodiment, the separation tank 1 is further provided with a baffle layer 2 above the cyclone separation layer 3 to further block the passage of the liquid and solid phases in the gas phase.

[0034] In this embodiment, the separation tank 1 is also provided with a flushing pipeline 5 above the baffle layer 2.

[0035] In this embodiment, the baffle layer 2 is configured as several sets of baffles.

[0036] Working principle and usage:

[0037] Separator 1, as the main body of the entire system, is responsible for separating the catalyst in the gas phase, ensuring effective catalyst recovery. Multi-stage separation is achieved through the configuration of a cyclone separation layer 3 and a baffle layer 2, improving separation efficiency and effectiveness. The cyclone separation layer 3 consists of several sets of parallel cyclone separators 4, increasing the separation area and improving separation efficiency. Baffles 31 fill the gaps between the cyclone separators 4, preventing airflow short-circuiting, ensuring uniform airflow distribution, and further improving the separation effect. The air inlet 41 is located at the lower end of the cylinder 46, with a cross-sectional area larger than the air outlet 43, and is designed as a regular hexagon, which helps to achieve uniform airflow distribution and improve separation efficiency. The air outlet 43 is located at the upper end of the cylinder 46, with a cross-sectional area smaller than the air inlet 41, which helps to form a high-speed airflow and improve the separation effect. The guide plate 45 is used for spiral guidance, guiding the airflow to form a vortex, enhancing centrifugal force, and improving the separation effect. The separation cylinder 42 is used for spiral guidance and outputting the separated solid and liquid phases, ensuring that the separated solid and liquid phases can be smoothly discharged and preventing blockage. The gas phase inlet 11 is located below the separator 1, ensuring that the gas flow enters from the bottom and exits from the top after passing through the cyclone separation layer 3. The gas phase outlet 12 is located at the top of the separator 1, ensuring that the separated gas phase exits from the top, reducing the catalyst content in the gas phase. The liquid-solid phase outlet 13 is located at the bottom of the separator 1, ensuring that the separated liquid and solid phases exit from the bottom, facilitating collection and treatment. The rectifier 44 is used for gas collection and rectification, ensuring uniform airflow distribution, reducing airflow turbulence, and improving separation efficiency. The baffle layer 2 is located above the cyclone separation layer 3, further blocking the passage of liquid and solid phases in the gas phase, improving separation efficiency. The combination of the baffle layer 2 and the cyclone separation layer 3 achieves multi-stage separation, improving the thoroughness and efficiency of separation. The flushing pipeline 5 is located above the baffle layer 2, and the interior of the separator 1 is cleaned periodically through the flushing pipeline 5, ensuring long-term stable operation of the system, preventing the accumulation of catalyst and impurities, and extending the service life of the system.

[0038] Example 2

[0039] The difference between this embodiment and embodiment 1 is that, in this embodiment, the cyclone separator 4 includes a cylinder 46, an air inlet 41 at the lower end of the cylinder 46 and an air outlet 43 at the upper end, and the cylinder 46 is also provided with a guide plate 45 for spiral guiding.

[0040] In this embodiment, the cross-sectional area of ​​the air inlet 41 is larger than the cross-sectional area of ​​the air outlet 43, and the air inlet 41 is configured as a regular hexagon.

[0041] In this embodiment, the air inlet 41 is further provided with a separation cylinder 42 for spiral guiding and outputting the solid and liquid phases, and the outlet height of the separation cylinder 42 is lower than the height of the gas inlet 11.

[0042] In this embodiment, the air outlet 43 is further provided with a rectifier 44 for collecting and rectifying airflow, and a gap is provided between the rectifier 44 and the separation cylinder 42 for the passage of spiral airflow.

[0043] In this embodiment, the baffle layer 2 is configured as a packing material.

[0044] 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 catalyst recovery system for the urea process in the preparation of cyclic carbonates, characterized in that: It includes a separation tank (1) for separating catalyst in the gas phase, the separation tank (1) having a cyclone separation layer (3) for separating liquid and solid phases in the gas phase, the cyclone separation layer (3) consisting of several sets of parallel cyclone separators (4) and baffles (31) for filling the gaps between the cyclone separators (4).

2. The urea-based cyclic carbonate catalyst recovery system according to claim 1, characterized in that: The cyclone separator (4) includes a cylinder (46), an air inlet (41) at the lower end of the cylinder (46) and an air outlet (43) at the upper end. The cylinder (46) is also provided with a flow guide plate (45) for spiral flow guidance.

3. The catalyst recovery system for urea-based cyclic carbonate preparation according to claim 2, characterized in that: The cross-sectional area of ​​the air inlet (41) is larger than that of the air outlet (43), and the air inlet (41) is a regular hexagon.

4. A catalyst recovery system for urea-based cyclic carbonate preparation according to claim 3, characterized in that: The separation tank (1) is also provided with a gas phase inlet (11) lower than the cyclone separation layer (3), a gas phase outlet (12) and a liquid-solid phase outlet (13) respectively located at the top and bottom of the separation tank (1).

5. A catalyst recovery system for urea-based cyclic carbonate preparation according to claim 4, characterized in that: The air inlet (41) is also provided with a separation cylinder (42) for spiraling flow and outputting the solid and liquid phases, and the outlet height of the separation cylinder (42) is lower than the height of the gas inlet (11).

6. A catalyst recovery system for urea-based cyclic carbonate preparation according to claim 5, characterized in that: The air outlet (43) is also provided with a rectifier shroud (44) for collecting and rectifying air, and a gap is provided between the rectifier shroud (44) and the separator (42) for passing through the spiral airflow.

7. A catalyst recovery system for urea-based cyclic carbonate preparation according to any one of claims 1-6, characterized in that: The separator (1) is further provided with a baffle layer (2) above the cyclone separation layer (3) to further block the passage of liquid and solid phases in the gas phase.

8. A catalyst recovery system for urea-based cyclic carbonate preparation according to claim 7, characterized in that: The separation tank (1) is also provided with a flushing pipeline (5) above the baffle layer (2).

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