Reaction system for synthesizing carbonic acid ester by heterogeneous method and method for synthesizing carbonic acid ester by heterogeneous method

Abstract

The application provides a reaction system and a synthesis method for synthesizing carbonates by a heterogeneous method, and the reaction system comprises, in the direction of a material flow, a gas-liquid bubbling bed reactor I, a buffer tank and a full-liquid-phase fixed bed reactor connected in series, and a circulating cooler and a circulating pump; the liquid phase outlet of the gas-liquid bubbling bed reactor is communicated with the inlet of the buffer tank, the outlet of the buffer tank is communicated with the inlet of the circulating cooler, the outlet of the circulating cooler is communicated with the inlet of the circulating pump; the outlet of the circulating pump is communicated with the liquid phase inlets of the gas-liquid bubbling bed reactor and the full-liquid-phase fixed bed reactor; the bottom of the gas-liquid bubbling bed reactor and / or the full-liquid-phase fixed bed reactor is provided with an inclined plane, and the inclination angle of each plane relative to the horizontal plane is 5-30 degrees. The application can solve the problems of poor temperature control sensitivity, easy temperature rise, large liquid circulation amount and reaction heat removal lag in the existing carbonates production device, can be applied to the industrialized production of carbonates, and has high industrial application value.

Description

Technical Field

[0001] This invention relates to a reaction system for heterogeneous synthesis of carbonates and a method for heterogeneous synthesis of carbonates. Background Technology

[0002] Industrially, carbonates are a very important class of organic compounds with broad market prospects. Important industrial carbonates include dimethyl carbonate, diphenyl carbonate, ethylene carbonate, and propylene carbonate. These carbonates are widely used in pigments for engineering plastics—polycarbonate and polyurethane—as electrolyte solvents for lithium-ion batteries, organic solvents, fuel additives, and as alkylating and acylating agents.

[0003] Currently, the main industrialized methods for synthesizing carbonates both domestically and internationally are the phosgene method, transesterification, haloalcohol method, ethylene and carbon dioxide synthesis method, and ethylene oxide and carbon dioxide synthesis method. The phosgene method was the earliest method for preparing carbonates, but it has been phased out due to its long process, low yield, and serious pollution from trace amounts of organochlorine compounds. The haloalcohol method requires high temperatures, at which carbonates decompose, resulting in high raw material consumption and numerous byproducts, thus preventing its industrialization. The ethylene and carbon dioxide synthesis method requires high pressure, posing an explosion hazard and hindering industrialization.

[0004] CN109647134A discloses a multi-stage serial bubbling bed-transport bed stacked CO2 adsorption reactor and method. The reactor includes a wind chamber, a central duct, a riser, and bubbling beds. Each bubbling bed includes a distribution plate on which CO2 adsorbent is placed. The central duct passes through the center of the bottom distribution plate, and the remaining distribution plates share a common riser. A water-cooled coil is installed in the dense phase zone of each bubbling bed within the riser. According to the claims, CO2-containing flue gas enters from the side of the wind chamber, passes through the bottom first-stage distribution plate, and enters the first-stage bubbling bed. While fluidizing the CO2 adsorbent in the first-stage bubbling bed, a decarbonization reaction occurs. Simultaneously, the first-stage water-cooled coil operates, absorbing the reaction heat within the first-stage bubbling bed and stabilizing the carbonation reaction temperature. Because this process is a gas-solid phase reaction, using water-cooled coils to remove heat from the gaseous phase is inefficient and unsuitable for removing strongly exothermic systems, hindering the widespread application of this process.

[0005] CN1371900A discloses a method and reactor for preparing propylene carbonate or ethylene carbonate. This method involves loading a catalyst into a reactor equipped with a heat removal device, separating the reaction zone from the product zone. In this reactor, heat can be removed simultaneously with the reaction, preventing high-temperature deactivation of the catalyst and extending its lifespan. However, in this method, the material distribution is prone to unevenness, with more vigorous reactions near the catalyst loading equipment. Conversely, the reaction may be slow or nonexistent near the catalyst loading equipment. If heat removal is not timely, localized overheating is more likely, leading to catalyst deactivation and hindering the reaction.

[0006] CN106478583B discloses a method for synthesizing ethylene carbonate. The process mainly includes a primary synthesis reactor and a secondary synthesis reactor. In this synthesis method, ethylene oxide reacts countercurrently with unreacted carbon dioxide in the secondary reactor in the primary reactor; in the secondary synthesis reactor, the product from the primary reaction reacts countercurrently with fresh carbon dioxide. During this synthesis process, external circulation is mainly used for heat removal. This method requires a large amount of liquid circulation, and the temperature rise control within the reactor is relatively delayed, which is not conducive to the reaction. Summary of the Invention

[0007] Heterogeneous synthesis reduces the need for subsequent product-catalyst separation, effectively decreasing energy consumption and investment. The resulting carbonates have high purity and good industrial applicability. However, this process releases a large amount of heat during the reaction of ethylene oxide and carbon dioxide to form carbonates. If this heat is not removed promptly, the resulting temperature rise will cause the carbonates to decompose, and the catalyst will easily deactivate, leading to a decrease in product yield. Therefore, strict and timely control of the temperature rise during the reaction is crucial.

[0008] The main objective of this invention is to solve the problems of insensitive temperature control, easy temperature runaway, large liquid circulation volume, and delayed reaction heat removal in carbonate production equipment, and to provide a reaction system and method for heterogeneous synthesis of carbonates.

[0009] According to a first aspect of the present invention, the present invention provides a reaction system for heterogeneous synthesis of carbonates, the reaction system comprising: a gas-liquid bubbling bed reactor and a buffer tank connected in series along the material flow direction; a fully liquid fixed bed reactor; and a circulating cooler and a circulating pump;

[0010] The liquid phase outlet of the gas-liquid bubbling bed reactor is connected to the inlet of the buffer tank, the outlet of the buffer tank is connected to the inlet of the circulating cooler, and the outlet of the circulating cooler is connected to the inlet of the circulating pump; the outlet of the circulating pump is connected to the liquid phase inlet of both the gas-liquid bubbling bed reactor and the all-liquid fixed bed reactor.

[0011] The bottom of the gas-liquid bubbling bed reactor and / or the all-liquid phase fixed bed reactor is set as an inclined plane, preferably with an inclination angle of 5°-30° relative to the horizontal plane, and more preferably with an inclination angle of 10°-20°.

[0012] According to a second aspect of the present invention, the present invention provides a method for heterogeneous synthesis of carbonates, characterized in that the method is carried out in the reaction system described in the present invention, wherein gaseous carbon dioxide and liquid ethylene oxide and circulating liquid from a circulating pump are mixed and then enter a gas-liquid bubble bed reactor through a first distributor from a liquid phase inlet. After the reaction, the catalyst is intercepted by a first solid intercepting wire mesh. The reaction products undergo gas-liquid separation at the top of the gas-liquid bubble bed reactor. The liquid reaction products enter a buffer tank through an overflow port, and then enter a circulating cooler for cooling and heat removal. After cooling, a portion is circulated back to the gas-liquid bubble bed reactor by a circulating pump, and the other portion enters a full liquid phase fixed bed reactor through a second distributor. The entire reaction system is controlled by the liquid level in the buffer tank.

[0013] This invention can solve the problems of insensitive temperature control, easy temperature runaway, large liquid circulation volume, and delayed reaction heat removal in existing carbonate production equipment. It can be applied to the industrial production of carbonates, has good practicality, and has high industrial application value.

[0014] Compared to other gas-liquid bubbling bed processes, this invention involves gas entering from the bottom and exiting from the top of the reactor, while liquid enters from the top and exits from the bottom. This results in a more uniform bed temperature and a more significant heat removal effect from the reactor jacket, thus reducing the circulation volume by 5%-15%.

[0015] Compared to other reactor internals, this invention features a horizontal wire mesh and grid at the bottom, with the catalyst loaded onto the mesh and grid. This invention has a simple structure, facilitates catalyst removal, and significantly reduces the amount of catalyst remaining in the reactor. Attached Figure Description

[0016] Figure 1 This is a system diagram of the synthesis of carbonates according to a preferred embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures

[0018] I is a gas-liquid bubbling bed reactor, and II is a buffer tank.

[0019] III is the circulating cooler, and IV is the circulating pump;

[0020] V-type fixed-bed reactor;

[0021] 1 is carbon dioxide, 2 is ethylene oxide, 3 is circulating liquid, 4 is liquid reaction product, 5 is liquid discharge from buffer tank, 7 is feed to liquid fixed bed reactor, and 8 is discharge from liquid fixed bed reactor.

[0022] 11 is the first intercepting wire mesh, 12 is the first distributor, and 13 is the discharge port;

[0023] FC is a flow controller, PC is a pressure controller, and LC is a level controller. Detailed Implementation

[0024] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0025] like Figure 1 As shown, the present invention provides a reaction system for the heterogeneous synthesis of carbonates, the reaction system comprising: a gas-liquid bubbling bed reactor I and a buffer tank II connected in series along the material flow direction; a fully liquid fixed bed reactor V; and a circulating cooler III and a circulating pump IV;

[0026] Among them, the liquid phase outlet of the gas-liquid bubbling bed reactor I is connected to the inlet of the buffer tank II, the outlet of the buffer tank is connected to the inlet of the circulating cooler III, and the outlet of the circulating cooler III is connected to the inlet of the circulating pump IV; the outlet of the circulating pump IV is connected to the liquid phase inlet of both the gas-liquid bubbling bed reactor and the all-liquid phase fixed bed reactor.

[0027] The bottom of the gas-liquid bubbling bed reactor and / or the all-liquid phase fixed bed reactor is set as an inclined plane, preferably with an inclination angle of 5°-30° relative to the horizontal plane, and more preferably with an inclination angle of 10°-20°.

[0028] This invention, by setting the aforementioned reaction system so that carbon dioxide, ethylene oxide, and circulating liquid are mixed from bottom to top before entering the reactor, not only allows the carbon dioxide to dissolve in the circulating liquid first, increasing reaction efficiency, but also utilizes the upward movement of gas and liquid to create a loose catalyst bed, ensuring uniform mixing, enhanced mass and heat transfer, more uniform bed temperature, and more stable control of the reaction system. The inclined bottom design facilitates the unloading of heterogeneous catalysts.

[0029] According to a preferred embodiment of the present invention, the discharge ports of the gas-liquid bubbling bed reactor and / or the all-liquid phase fixed bed reactor are each flush with the bottom of their respective reactors, and the diameter of each discharge port is preferably 50-2000 mm, more preferably 1000-1500 mm. By adopting this configuration, the present invention has the advantages of simple operation and convenient unloading.

[0030] like Figure 1As shown, according to a preferred embodiment of the present invention, the gas-liquid bubbling bed reactor I is provided with an overflow port, which is connected to the inlet of the buffer tank II. The all-liquid phase fixed bed reactor V is provided with an outlet control valve, and the buffer tank is provided with a level controller. The level controller of the buffer tank is connected to the outlet control valve of the all-liquid phase fixed bed reactor. By using the two together, the overflow port automatically flows into the buffer tank.

[0031] like Figure 1 As shown, in a preferred embodiment of the system according to the present invention, the gas-liquid bubbling bed reactor includes a bubbling bed reactor shell and a first distributor 12 and a first solid intercepting mesh 11 disposed inside the bubbling bed reactor shell. A loading port, a discharge port 13, an overflow port, and a gas outlet are disposed on the bubbling bed reactor shell, wherein the overflow port serves as the liquid phase outlet of the gas-liquid bubbling bed reactor. The first distributor is located at the bottom of the gas-liquid bubbling bed reactor and is used for distributing the gas and liquid mixture. The first solid intercepting mesh is located in the upper part of the gas-liquid bubbling bed reactor and is used for intercepting solids. The loading port is located on the side of the bubbling bed reactor, below the first solid intercepting mesh. The discharge port is located on the side of the bubbling bed reactor, at the bottom of the reactor side. The overflow port is located in the upper part of the bubbling bed reactor, above the first solid intercepting mesh. The gas outlet is located at the top of the bubbling bed reactor. By adopting the aforementioned configuration, the present invention has the advantages of low catalyst loss and simple control.

[0032] According to a preferred embodiment of the system of the present invention, the all-liquid phase fixed-bed reactor includes a fixed-bed reactor shell and a second distributor, a second solid intercepting mesh, a charging port, a discharging port, and a material outlet disposed inside the fixed-bed reactor shell; wherein, the second distributor is located at the bottom of the fixed-bed reactor and is used for liquid distribution; the second solid intercepting mesh is located in the upper part of the fixed-bed reactor and is used for intercepting solid catalyst; the charging port is located on the side of the fixed-bed reactor, below the second solid intercepting mesh; the discharging port is located at the bottom of the side of the fixed-bed reactor; the outlet is located at the top of the fixed-bed reactor; and an outlet control valve is disposed on the pipeline of the outlet. By adopting the aforementioned configuration, the present invention has the advantages of simple operation and convenient catalyst unloading.

[0033] According to a preferred embodiment of the present invention, the buffer tank is equipped with a level controller; preferably, the level controller of the buffer tank is connected to the outlet control valve of the all-liquid phase fixed bed reactor, and the two are used in conjunction to realize that the overflow port automatically flows into the buffer tank.

[0034] According to a preferred embodiment of the present invention, the distance between the first distributor and the bottom of the bubbling bed reactor is 100-500 mm, preferably 200-400 mm; by adopting the aforementioned setting, the present invention has the advantage of high catalyst utilization.

[0035] According to a preferred embodiment of the present invention, the distance between the second distributor and the bottom of the fixed bed reactor is 100-500 mm, preferably 200-400 mm; by adopting the aforementioned setting, the present invention has the advantage of high catalyst utilization.

[0036] According to a preferred embodiment of the present invention, the first distributor and the second distributor are each tubular distributors, preferably with openings at the top and bottom, and the aperture is Φ5-10. By adopting the aforementioned configuration, the present invention has the advantage of uniform gas distribution.

[0037] According to a preferred embodiment of the present invention, the first distributor and the second distributor are each wrapped with a 40-60 mesh wire mesh. By adopting the aforementioned arrangement, the present invention has the advantages of preventing heterogeneous catalysts from entering the distributors and causing blockages, and of redistributing the gas for more uniform mixing.

[0038] According to a preferred embodiment of the present invention, the shapes of the first solid intercepting wire mesh and / or the second solid intercepting wire mesh are preferably arc-shaped, arched, or conical. By adopting the aforementioned configuration, the present invention has the advantages of high wire mesh throughput and low reactor resistance drop.

[0039] According to a preferred embodiment of the present invention, the ratio of the area of ​​the first solid intercepting wire mesh to the cross-sectional area of ​​the bubbling bed reactor is 1.5-5; by adopting the aforementioned configuration, the present invention has the advantages of large wire mesh throughput and small reactor resistance drop.

[0040] According to a preferred embodiment of the present invention, the ratio of the area of ​​the second solid intercepting wire mesh to the cross-sectional area of ​​the fixed-bed reactor is 1.5-5. By adopting the aforementioned configuration, the present invention has the advantages of high wire mesh throughput and low reactor resistance drop.

[0041] According to a preferred embodiment of the present invention, the gas-liquid bubbling bed reactor I and / or the all-liquid phase fixed bed reactor V are configured to use a jacket / coil method for heat removal, and the heat removal medium is preferably saturated water at 100-150°C.

[0042] According to a preferred embodiment of the present invention, the cooling medium of the circulating cooler III is selected from saturated water, hot water and cooling water.

[0043] In this invention, each unit and each structure within a unit can be equipped with flow control valves, temperature measuring, pressure measuring, and other components as needed, as described in this invention. Figure 1 The flow control valves shown on the different pipelines are: FC is a flow controller that controls the circulation volume, PC is a pressure controller that controls the pressure of the reaction system, and LC is a level controller that controls the level of the buffer tank.

[0044] Specifically, such as Figure 1As shown, a pressure controller PC is installed at the top of the gas-liquid bubbling bed reactor I to control the pressure of the reaction system.

[0045] A level controller (LC) is installed on the side wall of the buffer tank to monitor the liquid level in the tank.

[0046] Control valves are installed on the top outlet pipelines of the gas-liquid bubbling bed reactor I and the all-liquid fixed bed reactor V. By installing control valves in conjunction with the LC on the side wall of the buffer tank, stable control of the temperature, pressure and liquid level of the reaction system can be achieved.

[0047] The remaining structures can be equipped with various auxiliary accessories as needed, which is a matter of great interest to those skilled in the art, and will not be described in detail here.

[0048] like Figure 1 As shown, this invention provides a heterogeneous method for synthesizing carbonates. The method is carried out in the reaction system described in this invention. Gas carbon dioxide 1, liquid ethylene oxide 2, and circulating liquid 3 from circulating pump IV are mixed and then enter the gas-liquid bubbling bed reactor I through a first distributor via the liquid phase inlet. After the reaction, the catalyst is intercepted by a first solid intercepting wire mesh. The reaction products undergo gas-liquid separation at the top of the gas-liquid bubbling bed reactor I. The liquid reaction product 4 overflows into a buffer tank II. The liquid output 5 from the buffer tank then enters a circulating cooler III for cooling and heat removal. A portion of the liquid is circulated back to the gas-liquid bubbling bed reactor I via circulating pump IV, while the other portion (the liquid feed 7) enters a full-liquid phase fixed bed reactor V through a second distributor. The liquid level in the buffer tank controls the output of the entire reaction system, and the liquid output 8 is collected from the top of the full-liquid phase fixed bed reactor V.

[0049] In this invention, the operating conditions of each unit can be adjusted as needed. The following examples illustrate preferred embodiments, but these should not be construed as limiting the scope of the invention.

[0050] According to a preferred embodiment of the present invention, the operating conditions of the gas-liquid bubbling bed reactor I include: temperature 80-150℃ and pressure 2-5MPa.

[0051] According to a preferred embodiment of the present invention, the operating conditions of buffer tank II include: a temperature of 80-150°C.

[0052] According to a preferred embodiment of the present invention, the operating conditions of the circulating cooler III include a temperature of 60-100°C.

[0053] According to a preferred embodiment of the present invention, the operating conditions of the circulating pump IV include: temperature 60-100℃ and pressure boost 0.2-0.5MPa.

[0054] According to a preferred embodiment of the present invention, the operating conditions of the all-liquid phase fixed bed reactor V include: 100-150°C.

[0055] According to a preferred embodiment of the present invention, the ratio of gaseous carbon dioxide to liquid ethylene oxide is 1.02-1.3.

[0056] According to a preferred embodiment of the present invention, the catalyst is one or more of ionic liquid supported catalysts, resins, and alkaline earth metal solid catalysts.

[0057] According to a preferred embodiment of the present invention, the method for controlling the output of the entire reaction system by means of the level of the buffer tank includes: the level controller of the buffer tank is connected to the outlet control valve of the all-liquid phase fixed bed reactor; when the level of the buffer tank is high, the control valve is opened wide, and vice versa.

[0058] In this invention, the all-liquid phase fixed bed reactor does not separately replenish CO2, operates with the liquid phase full tank, and the output is controlled by the liquid level of the buffer tank.

[0059] In this invention, the solubility of gaseous carbon dioxide in the reactants can be enhanced by increasing the dissolution time and dispersing small bubbles.

[0060] In this invention, one or more streams of CO2 enter the lower part of the gas-liquid bubbling bed reactor in the reaction system, and are then uniformly distributed by a gas distributor.

[0061] The following embodiments are in accordance with Figure 1 The process shown synthesizes carbonates, wherein,

[0062] The gas-liquid bubbling bed reactor includes a bubbling bed reactor shell and a first distributor and a first solid intercepting wire mesh disposed inside the bubbling bed reactor shell. A loading port, a unloading port, an overflow port and a gas outlet are disposed on the bubbling bed reactor shell, wherein the overflow port serves as the liquid phase outlet of the gas-liquid bubbling bed reactor.

[0063] The all-liquid phase fixed bed reactor includes a fixed bed reactor shell and a second distributor, a second solid intercepting mesh, a loading port, a discharge port, an outlet, and an outlet control valve disposed inside the fixed bed reactor shell. The buffer tank is equipped with a level controller, which is connected to the outlet control valve of the all-liquid phase fixed bed reactor. Through the cooperation of the two, the overflow port can automatically flow into the buffer tank.

[0064] The bottoms of both the gas-liquid bubbling bed reactor and the all-liquid phase fixed bed reactor are designed as inclined planes with inclination angles of 15° and 20°, respectively.

[0065] Furthermore, the discharge ports of the gas-liquid bubbling bed reactor and the all-liquid phase fixed bed reactor have diameters of 1500 mm and 1000 mm, respectively.

[0066] The distance between the first distributor and the bottom of the bubbling bed reactor is 300 mm;

[0067] The distance between the second distributor and the bottom of the fixed-bed reactor is 200 mm;

[0068] Both the first and second distributors are tubular distributors with openings at the top and bottom, with a hole diameter of Φ8 and wrapped with 50-mesh wire mesh.

[0069] The ratio of the area of ​​the first solid intercepting wire mesh to the cross-sectional area of ​​the bubbling bed reactor is 3;

[0070] The ratio of the area of ​​the second solid intercepting wire mesh to the cross-sectional area of ​​the fixed bed reactor is 1.5.

[0071] Example 1

[0072] Gas carbon dioxide 1, liquid ethylene oxide 2, and circulating liquid 3 from circulating pump IV are mixed and then enter the gas-liquid bubbling bed reactor I through the first distributor via the liquid phase inlet. After the reaction, the catalyst is intercepted by the first solid interception wire mesh. The reaction products undergo gas-liquid separation at the top of the gas-liquid bubbling bed reactor I. The liquid reaction product 4 enters the buffer tank II through the overflow port. Then, the liquid discharge 5 from the buffer tank enters the circulating cooler III for cooling and heat removal. A portion of the liquid is then circulated back to the gas-liquid bubbling bed reactor I via circulating pump IV, while the other portion, the liquid fixed bed reactor feed 7, enters the full liquid phase fixed bed reactor V through the second distributor. The entire reaction system is controlled by the buffer tank level, and the liquid fixed bed reactor discharge 8 is collected from the top of the full liquid phase fixed bed reactor V. The method of controlling the entire reaction system by the buffer tank level includes: the buffer tank level signal is connected to the control valve at the outlet of the full liquid phase fixed bed reactor. When the buffer tank level is high, the control valve is opened wider, and vice versa.

[0073] No catalyst residue remained in the reactor during the catalyst unloading process.

[0074] The gas-liquid bubbling bed reactor and the all-liquid phase fixed bed reactor are configured to use a jacketed heat removal method, and the heat removal medium is saturated water at 110°C.

[0075] The cooling medium for the circulating cooler is saturated water at 32°C.

[0076] The operating conditions for the gas-liquid bubbling bed reactor include: temperature 100℃ and pressure 3.5MPa;

[0077] The operating conditions for the buffer tank include: a temperature of 100℃;

[0078] The operating conditions for the circulating cooler include: the temperature of the cooled material is 85℃;

[0079] The operating conditions for the circulating pump include: a temperature of 85℃;

[0080] The operating conditions for the all-liquid phase fixed-bed reactor include: temperature 100-110℃, temperature gradient distribution in the bed, and pressure 3.6MPa;

[0081] The ratio of gaseous carbon dioxide to liquid ethylene oxide is 1.2;

[0082] The catalyst is a resin catalyst, and the amount of catalyst used is 8 tons.

[0083] Example 2

[0084] Similar to Example 1, except that the bottoms of both the gas-liquid bubbling bed reactor and the all-liquid fixed bed reactor are set as inclined planes with an inclination angle of 3°. Compared to Example 1, at least 5% of the catalyst remains in the reactor during the catalyst unloading process.

[0085] Example 3

[0086] Similar to Example 1, except that the distance between the first distributor and the bottom of the reactor is 1000 mm, the ethylene oxide conversion rate is reduced by at least 1%.

[0087] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A reaction system for heterogeneous synthesis of carbonates, characterized in that, The reaction system includes: a gas-liquid bubbling bed reactor (I) and a buffer tank (II) connected in series along the material flow direction; a fully liquid fixed bed reactor (V); and a circulating cooler (III) and a circulating pump (IV). Among them, the liquid phase outlet of the gas-liquid bubbling bed reactor (I) is connected to the inlet of the buffer tank (II), the outlet of the buffer tank is connected to the inlet of the circulating cooler (III), and the outlet of the circulating cooler (III) is connected to the inlet of the circulating pump (IV); the outlet of the circulating pump (IV) is connected to the liquid phase inlet of both the gas-liquid bubbling bed reactor and the all-liquid fixed bed reactor. The bottom of the gas-liquid bubbling bed reactor and / or the all-liquid phase fixed bed reactor is set as an inclined plane with an inclination angle of 5°-30° relative to the horizontal plane. The gas-liquid bubbling bed reactor includes a bubbling bed reactor shell and a first distributor and a first solid intercepting wire mesh disposed inside the bubbling bed reactor shell. A loading port, a unloading port, an overflow port and a gas outlet are disposed on the bubbling bed reactor shell, wherein the overflow port serves as the liquid phase outlet of the gas-liquid bubbling bed reactor. The all-liquid phase fixed-bed reactor includes a fixed-bed reactor shell and a second distributor, a second solid intercepting wire mesh, a charging port, a discharging port, and a material outlet, all disposed inside the fixed-bed reactor shell. The discharge ports of the gas-liquid bubbling bed reactor and / or the all-liquid phase fixed bed reactor are each level with the bottom of their respective reactors, and the diameter of each discharge port is 50-2000 mm. The gas-liquid bubbling bed reactor (I) is equipped with an overflow port, which is connected to the inlet of the buffer tank (II). The all-liquid phase fixed bed reactor (V) is equipped with an outlet control valve, and the buffer tank is equipped with a level controller. The level controller of the buffer tank is connected to the outlet control valve of the all-liquid phase fixed bed reactor. Through the cooperation of the two, the overflow port can automatically flow into the buffer tank.

2. The reaction system according to claim 1, wherein, The bottom of the gas-liquid bubbling bed reactor and / or the all-liquid phase fixed bed reactor is set as an inclined plane with an inclination angle of 10°-20° relative to the horizontal plane.

3. The reaction system according to claim 1, wherein, The discharge ports of the gas-liquid bubbling bed reactor and / or the all-liquid phase fixed bed reactor are each level with the bottom of their respective reactors, and the diameter of each discharge port is 1000-1500 mm.

4. The reaction system according to claim 1, in, The first distributor, located at the bottom of the gas-liquid bubbling bed reactor, is used for distributing gas and liquid mixtures. The first solid interception wire mesh is located in the upper part of the gas-liquid bubbling bed reactor and is used to intercept solids; The filling port is located on the side of the bubbling bed reactor, below the first solid interception wire mesh; The discharge port is located on the side of the bubbling bed reactor, at the bottom of the reactor side. The overflow port is located at the top of the bubbling bed reactor, above the first solid interception wire mesh. The gas outlet is located at the top of the bubbling bed reactor; and / or The second distributor, located at the bottom of the fixed-bed reactor, is used for liquid distribution. The second solid interception mesh is located in the upper part of the fixed-bed reactor and is used to intercept solid catalysts; The filling port is located on the side of the fixed-bed reactor, below the second solid interception wire mesh; The discharge port is located at the bottom side of the fixed-bed reactor. The outlet is located at the top of the fixed-bed reactor; An outlet control valve is installed on the pipeline at the outlet; and / or The buffer tank is equipped with a level controller.

5. The reaction system according to claim 4, wherein, The level controller of the buffer tank is connected to the outlet control valve of the all-liquid phase fixed bed reactor. The two work together to enable the overflow to automatically flow into the buffer tank.

6. The reaction system according to claim 1, wherein, The distance between the first distributor and the bottom of the bubbling bed reactor is 100-500 mm; and / or The second distributor is 100-500 mm away from the bottom of the fixed-bed reactor; and / or The first distributor and the second distributor each employ a tubular distributor; and / or The first distributor and the second distributor are each wrapped with 40-60 mesh wire mesh.

7. The reaction system according to claim 6, wherein, The distance between the first distributor and the bottom of the bubbling bed reactor is 200-400 mm; and / or The second distributor is 200-400 mm away from the bottom of the fixed-bed reactor; and / or The first and second distributors are each tubular distributors with openings at the top and bottom, with an aperture of Φ5-10.

8. The reaction system according to claim 1, wherein, The first solid intercepting wire mesh and / or the second solid intercepting wire mesh are each arc-shaped, arched, or conical; and / or The ratio of the area of ​​the first solid intercepting wire mesh to the cross-sectional area of ​​the bubbling bed reactor is 1.5-5; and / or The ratio of the area of ​​the second solid intercepting wire mesh to the cross-sectional area of ​​the fixed bed reactor is 1.5-5.

9. The reaction system according to claim 1, wherein, The gas-liquid bubbling bed reactor (I) and / or the all-liquid phase fixed bed reactor (V) are configured to use a jacket / coil method for heat removal; The cooling medium for the circulating cooler (III) is selected from saturated water, hot water, and cooling water.

10. The reaction system according to claim 9, wherein, The heat removal medium is saturated water at 100-150℃.

11. A method for synthesizing carbonates using a heterogeneous process, characterized in that, This method is carried out in the reaction system described in any one of claims 1-10, wherein, Gas carbon dioxide and liquid ethylene oxide, along with circulating liquid from the circulating pump (IV), are mixed and enter the gas-liquid bubbling bed reactor (I) through the first distributor via the liquid phase inlet. After the reaction, the catalyst is intercepted by the first solid interception wire mesh. The reaction products undergo gas-liquid separation at the top of the gas-liquid bubbling bed reactor (I). The liquid flows through the overflow port into the buffer tank (II), and then into the circulating cooler (III) for cooling and heat removal. After cooling, a portion of the liquid is circulated back to the gas-liquid bubbling bed reactor (I) via the circulating pump (IV), while the other portion flows through the second distributor into the all-liquid phase fixed bed reactor (V). The entire reaction system is controlled by the liquid level in the buffer tank.

12. The method according to claim 11, wherein, The operating conditions for the gas-liquid bubbling bed reactor (I) include: temperature 80-150℃, pressure 2-5MPa and / or The operating conditions for the buffer tank (II) include: a temperature of 80-150°C; and / or The operating conditions for the circulating cooler (III) include: a temperature of 60-100°C; and / or The operating conditions for the circulating pump (IV) include: temperature 60-100℃, pressure boost 0.2-0.5MPa; and / or The operating conditions for a fully liquid-phase fixed-bed reactor (V) include: 100-150℃.

13. The method according to claim 11, wherein, The ratio of gaseous carbon dioxide to liquid ethylene oxide is 1.02-1.3; and / or The catalyst is one or more of the following: ionic liquid supported catalyst, resin, and alkaline earth metal solid catalyst.

14. The method according to any one of claims 11-13, wherein, The method of controlling the output of the entire reaction system by means of buffer tank level includes: the buffer tank level controller is connected to the outlet control valve of the all-liquid phase fixed bed reactor. When the buffer tank level is high, the control valve is opened wider, and vice versa.

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