A reaction device and process for hydrogenating oxalate ester to ethylene glycol

Abstract

The present invention relates to a reaction device and process for hydrogenating oxalate ester to ethylene glycol, including a fluidized bed reactor (100), a fixed bed reactor (200), a filter (300) and a steam drum (400). The bottom of the fluidized bed reactor (100) is connected to a raw gas inlet pipe (1), the top is connected to the filter (300), the filter (300) is connected to the fixed bed reactor (200), and the steam drum (400) is connected to the fluidized bed reactor (100) through a circulation pipeline. The oxalate ester and hydrogen are successively subjected to two reactions in the fluidized bed reactor and the fixed bed reactor. By using the fluidized bed, good heat removal and temperature control can be achieved, and a medium conversion efficiency can be obtained. Then, by connecting a fixed bed reactor in series, high productivity of a single reactor system can be realized, the investment, energy consumption and total cost per unit output can be reduced, and its competitiveness with the petrochemical route can be improved.

Description

Technical Field

[0001] The present invention relates to a device and process for producing ethylene glycol by a coal chemical route, particularly to a method for producing ethylene glycol by hydrogenating dimethyl oxalate or diethyl oxalate, which is suitable for large-scale production of ethylene glycol by combining a fluidized bed and a fixed bed reactor. Background Art

[0002] Ethylene glycol is an important basic organic chemical raw material, mainly used as a polycondensation monomer for polyester. Due to the rapid growth of the polyester industry, the global production capacity of ethylene glycol is close to 40 million tons / year. The traditional production route is based on the petroleum route of ethylene-ethylene oxide. The production in China far from meets the demand, and the import volume is very large. The import dependence has been above 70% in the past decade, which seriously restricts the development of the polyester industry in China.

[0003] The resource characteristics of China are rich in coal, scarce in oil and poor in gas. Developing a coal chemical route for producing ethylene glycol has strategic and practical significance. The coal chemical route for producing ethylene glycol includes three reaction steps: (1) Coupling: CO and nitrite (methyl ester or ethyl ester) are coupled to produce oxalate and co-produce NO; (2) Hydrogenation: Oxalate is hydrogenated to produce ethylene glycol and co-produce methanol (ethanol); (3) Esterification: NO and methanol (ethanol) are oxidized and esterified to produce methyl (ethyl) nitrite and co-produce water. The three reactions form a cycle of NO and methanol (ethanol). The overall reaction is:

[0004] 2CO + 4H 2 + 0.5O 2 =(CH 2 OH) 2 + H 2 O

[0005] Obviously, this reaction is very close to the reaction of methanol. Therefore, compared with the traditional ethylene-ethylene oxide route, the coal chemical route has significant resource advantages.

[0006] The coal chemical route for ethylene glycol was first invented by Union Carbide Chemicals in the United States and Ube Industries in Japan in the 1980s. Chinese scientists started basic research in the 1990s. Especially since this century, many domestic units have carried out technology development and industrialized in the past decade and developed rapidly. The built + under construction + planned production capacity will reach 15 million tons / year. However, in recent years, due to the low price of oil, the coal chemical ethylene glycol route has large losses due to small single-unit production capacity, large investment and high energy consumption, making it difficult to compete with the petroleum route.

[0007] Therefore, the technical development direction of coal chemical ethylene glycol is how to reduce investment, increase the single-unit (i.e., the production capacity of a single reactor), reduce investment, reduce energy consumption, and improve the competitiveness with the petroleum route.

[0008] In the current technology, the problem with the hydrogenation reaction is that the reaction temperature window is relatively narrow. Generally, the higher the reaction temperature, the better, but the temperature of this reaction cannot be too high. If it is too high, by-product 1,2-butanediol, which is difficult to separate, will be produced, and high temperature will also cause sintering inactivation of the copper-based catalyst. Therefore, the feasible operating temperature range is narrow. On the other hand, the reactor used is a heat-exchanging shell-and-tube fixed-bed reactor. Limited by the heat transfer capacity, the pipe diameter is small, which limits the production capacity. Generally, the production capacity of a single reactor is about 50,000 tons / year.

[0009] According to the principles of chemical reaction engineering, different reactors have their own advantages and disadvantages. In the gas-solid reaction system, the solution that can better solve the heat transfer problem is to use a fluidized bed reactor. However, the reaction efficiency of the fluidized bed reaction is not as high as that of the fixed bed. Moreover, for different reactions, combined with the characteristics of the reaction, there are different specific implementation schemes.

[0010] For the hydrogenation reaction of oxalate, Patent Document 201110045352 (fluidized bed catalyst for catalytic reaction of oxalate to ethylene glycol) discloses a copper catalyst modified with promoters cerium and niobium for use in a fluidized bed reactor; 201110045364 (method for producing ethylene glycol by fluidized bed catalytic reaction of oxalate) uses a fluidized bed reactor, and the catalyst is modified with bismuth and tungsten. Although the literature states that a 100% conversion rate of oxalate can be obtained, in fact, it is very difficult to achieve because the characteristic of the fluidized bed reactor is that due to the non-uniformity of gas-solid flow, especially the existence of backmixing caused by large bubbles, it is very difficult to reach a very high conversion efficiency, let alone 100% (even theoretically it cannot be achieved unless the catalyst loading is infinite). Obviously, it is not applicable. Therefore, there has been no further development and industrial application so far. Summary of the Invention

[0011] The object of the present invention is to overcome the problems existing in the above-mentioned prior art, such as low production capacity, which limits large-scale production, and difficult improvement of conversion efficiency. A reaction device and process technology for hydrogenating oxalate to ethylene glycol are provided. This technology has a simple structure, high production capacity, high conversion efficiency, and is particularly suitable for the needs of large-scale production.

[0012] The object of the present invention can be achieved by the following technical solutions: A reaction device for hydrogenating oxalate ester to ethylene glycol, comprising a fluidized bed reactor (100), a fixed bed reactor (200), a filter (300) and a steam drum (400). The bottom of the fluidized bed reactor (100) is connected to a raw gas inlet pipe (1), the top is connected to the filter (300), and the filter (300) is connected to the fixed bed reactor (200). The steam drum (400) is connected to the fluidized bed reactor (100) through a circulation pipeline. Combining the advantages of high heat removal capacity of the fluidized bed reactor and high conversion rate of the fixed bed reactor, it can achieve good temperature control and stable operation of the reactor at the same time.

[0013] A filter is also connected between the fluidized bed reactor and the fixed bed reactor through a dust-containing gas pipeline and a clean gas pipeline to achieve gas-solid separation of fine particle catalysts, thoroughly recover the catalysts, reduce waste, and eliminate blockage in the subsequent fixed bed reaction, ensuring stable and safe operation.

[0014] The fluidized bed reactor includes a bottom gas distribution area, an intermediate reaction area, and a top gas-solid separation area. A gas distributor a is provided in the gas distribution area, catalyst a and heat exchange tubes are filled in the intermediate reaction area, and a gas-solid separator is provided in the gas-solid separation area to ensure heat removal and control the reactor temperature while the reaction is carried out, and ensure uniform distribution of reaction gases and stable reaction operation.

[0015] The heat exchange tubes form a circulation loop with the steam drum through an inlet water pipeline and an outlet water pipeline; multiple parallel heat exchange tubes are uniformly arranged in the reaction area, and the catalyst is filled between the heat exchange tubes to ensure that excess heat released during the reaction produces steam.

[0016] The particle size of the catalyst a is between 20 and 1000 microns, preferably between 50 and 500 microns.

[0017] The fixed bed reactor is filled with catalyst b and a gas distributor b, and the particle size of the catalyst b is between 2 and 10 mm, preferably between 4 and 8 mm, reducing the resistance and ensuring high reaction efficiency.

[0018] The fixed bed reactor is an adiabatic reactor with a simple structure and high efficiency, reducing investment. The catalyst b is spherical, cylindrical, annular or porous cylindrical, preferably annular, with low gas resistance and reduced energy consumption.

[0019] The described filter is equipped with a filter tube, which is a microporous metal sintered tube, a ceramic tube, a glass fiber cloth bag or an organic polymer fiber cloth bag, and has three interfaces. It is connected to the top of the upstream fluidized bed reactor through a dust-containing gas pipeline, to the downstream fixed bed reactor through a clean gas pipeline, and then to the lower part of the fluidized bed reactor through a catalyst particle reflux pipeline, ensuring rapid and continuous recovery of the catalyst, purification of the reaction gas, and reduction of blockage in the downstream fixed bed reactor.

[0020] The reaction process for producing ethylene glycol by hydrogenating oxalate using the described device includes the following steps:

[0021] 1. Primary reaction: The raw material gas enters the lower cavity of the fluidized bed reactor (100) through the raw material gas inlet pipe (1), and after being evenly distributed by the gas distributor a (102), enters the fluidized section containing catalyst a (101), contacts with catalyst a (101) to carry out the catalytic reaction of hydrogenating oxalate to produce ethylene glycol and by-product methanol or ethanol.

[0022] 2. Heat removal: The heat released by the hydrogenation reaction in the fluidized bed reactor not only raises the temperature of the reaction gas to the set temperature, i.e., the temperature of the fluidized bed reactor, but also removes the excess reaction heat through the heat exchange between the reaction gas and the heat exchange tubes, and forms a water circulation with the steam drum through the inlet water pipeline and the outlet water pipeline to produce steam in the steam drum.

[0023] 3. Gas-solid separation: The reaction gas obtained from the hydrogenation reaction in the fluidized bed reactor enters the upper gas-solid separation zone for gas-solid separation. Larger-sized catalyst particles entrained by the reaction gas are separated by gravity sedimentation, smaller-sized catalyst particles are separated by cyclone separation in the gas-solid separator, and fine-sized catalyst is transported to the filter outside the reactor through the dust-containing gas pipeline for thorough filtration and separation. The fine particle catalyst obtained by filtration returns to the fluidized section of the fluidized bed reactor through the catalyst reflux pipeline for recycling, and the clean reaction gas obtained enters the downstream fixed bed reactor through the clean pipeline.

[0024] 4. Secondary reaction: The clean reaction gas undergoes a second reaction in the fixed bed reactor to achieve a high conversion efficiency.

[0025] The volume composition of the raw material gas entering the fluidized bed reactor (100) in step 1 is 1-5% oxalate, and the rest is hydrogen, etc.; the oxalate is dimethyl oxalate or diethyl oxalate; the raw material gas is a configured mixed gas.

[0026] The top pressure of the fluidized bed reactor is 1.5 - 5.5 Mpa, as both too high and too low pressures are not conducive to the reaction. The top temperature is 160 - 200 °C, preferably 170 - 190 °C. If the temperature is too low, the reaction rate is low, and if it is too high, side reactions occur. Moreover, the fixed bed reactor operates adiabatically, causing the reaction temperature to continuously increase, which is beneficial to improving the conversion efficiency.

[0027] After gas-solid separation in step 3, the solid content in the clean reaction gas entering the fixed bed reactor is less than 5 mg / Nm 3 ; The fixed bed reactor operates adiabatically;

[0028] The conversion rate of dimethyl oxalate or ethyl oxalate in the fluidized bed reactor is 80 - 90%, and the total conversion rate of dimethyl oxalate or ethyl oxalate in the two reactors is between 95 - 99%.

[0029] The catalysts used in the above fluidized bed reactor and fixed bed reactor are the commonly used catalysts for hydrogenating oxalate esters to ethylene glycol, which are copper-based catalysts, and the carrier is inert silica.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. The present invention connects the fluidized bed and the fixed bed in series, taking advantage of the respective advantages of the fluidized bed and fixed bed reactions and overcoming their respective disadvantages. The heat release of this reaction is not high, belonging to a medium and small heat release system. The catalyst has good stability and the reaction rate is not very high. The present invention first uses the fluidized bed to achieve good heat removal and temperature control, which can increase the flow rate of the reaction material per unit volume, thereby improving the production capacity, that is, a high-capacity reaction device is proposed to obtain a medium conversion efficiency. Then, by connecting a fixed bed reactor in series, high production capacity of a single reactor system can be achieved, reducing the investment, energy consumption, and total cost per unit output, and enhancing its competitiveness with the petrochemical route; it can produce a large amount of by-product dicarbonate esters, further improving the economic benefits of the device.

[0032] 2. Since the gas outlet of the fluidized bed reactor will entrain a large amount of catalyst dust, simply connecting the fixed bed in series will clog the subsequent fixed bed reactor. Therefore, the present invention provides a filter between the two reactors, improving the service life of the device. Brief Description of the Drawings

[0033] Figure 1 It is a schematic diagram of the reaction device for hydrogenating oxalate esters to ethylene glycol according to the present invention.

[0034] Reference numerals in the figure: fluidized bed reactor 100, catalyst a 101, gas distributor a 102, heat exchange tube 103, gas-solid separator 104, fixed bed reactor 200, catalyst b 201, gas distributor b 202, filter 300, steam drum 400;

[0035] Raw material gas inlet pipe 1, dust-containing gas pipeline 2, clean gas pipeline 3, catalyst particle return pipeline 4, total water inlet pipeline 6, steam product pipeline 7, water inlet pipeline 8, water outlet pipeline 9. Specific implementation mode

[0036] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Example 1:

[0038] As Figure 1 shown, this embodiment corresponds to a production capacity of 100,000 tons of ethylene glycol. The reaction device for hydrogenating dimethyl oxalate to ethylene glycol includes a fluidized bed reactor 100 and a fixed bed reactor 200, and the fluidized bed reactor 100 is located upstream of the fixed bed reactor 200, that is, a fixed bed reactor is connected in series behind the fluidized bed reaction. The diameter of the fluidized bed reactor is 1.8 meters and the height is 15 meters. The diameter of the fixed bed reaction is 1.3 meters and the height is 6 meters. At the same time, a filter 300 is also connected between the fluidized bed reactor 100 and the fixed bed reactor 200 through the dust-containing gas pipeline 2 and the clean gas pipeline 3 to achieve gas-solid separation. The material of this filter is a stainless steel metal particle sintered microporous tube, which can effectively filter and separate fine particle catalysts. The fluidized bed reactor 100 includes a bottom gas distribution area, an intermediate reaction area, and a top gas-solid separation area. Among them, a gas distributor a102 is provided in the gas distribution area, and catalyst a101 is filled in the intermediate reaction area. The catalyst filling amount is 5m 3 , and the particle size of the catalyst a101 is between 50 and 350 microns. Multiple parallel heat exchange tubes 103 are evenly arranged in the reaction area, and the catalyst a101 is filled between the heat exchange tubes 103. The gas distributor a102 is a perforated plate distributor, and the heat exchange tubes are stainless steel tubes with a total area of 100m 2 , the diameter of the heat exchange tube is 50 mm, the length is 6 meters, and there are 100 heat exchange tubes in parallel. A gas-solid separator 104 is provided in the gas-solid separation area, and the gas-solid separator 104 is a cyclone separator. The heat exchange tube 103 forms a circulation loop with the steam drum 400 through the water inlet pipeline 8 and the water outlet pipeline 9, and can produce 2.8 tons / hr of steam;

[0039] The fixed bed reactor 200 is filled with catalyst b201 and gas distributor b202, and the catalyst b201 is a circular ring catalyst with a diameter of 6 mm, a ring wall thickness of 1.5 mm, and a ring height of 6 mm. The filling amount is 5m 3The fixed bed reactor 200 is an adiabatic reactor, and the catalyst b201 is in the shape of a ring. The filter 300 is equipped with a filter tube, and the filter tube is a microporous metal sintered tube. The filter has three interfaces, which are respectively connected to the top of the upstream fluidized bed reactor 100 through the dusty gas pipeline 2, connected to the downstream fixed bed reactor 200 through the clean gas pipeline 3, and then connected to the lower part of the fluidized bed reactor 100 through the catalyst particle reflux pipeline 4, and the recovered fine particle catalyst is refluxed to the fluidized bed reaction.

[0040] The reaction process of hydrogenating dimethyl oxalate to produce ethylene glycol according to the above device comprises the following steps:

[0041] (1) Primary reaction: The raw gas enters the lower cavity of the fluidized bed reactor 100 through the raw gas inlet pipe 1, and is evenly distributed by the gas distributor a102, and enters the fluidized section containing the catalyst a101, where it contacts the catalyst a101 to react with dimethyl oxalate to produce ethylene glycol, thereby producing ethylene glycol and co-producing methanol. The volume composition of the raw gas is dimethyl oxalate = 2%, and the remaining components are hydrogen;

[0042] (2) Heat removal: The heat released by the hydrogenation reaction in the fluidized bed reactor 100 increases the temperature of the reaction gas from 40°C to 175°C in the fluidized bed reactor 100. On the other hand, the excess reaction heat is removed through heat exchange between the reaction gas and the heat exchange tube 103. A water cycle is formed with the steam drum 400 through the inlet water pipeline 8 and the outlet water pipeline 9. Steam is produced in the steam drum 400. The steam output is 2.5 tons / hr and is discharged from the steam product pipeline 7. Fresh desalinated and deoxygenated soft water is added to the steam drum through the total water inlet pipeline 6 to maintain a stable liquid level in the steam drum.

[0043] (3) Gas-solid separation: The reaction gas obtained by the hydrogenation reaction in the fluidized bed reactor 100 enters the upper gas-solid separation zone for gas-solid separation. The larger catalyst particles entrained by the reaction gas are separated by gravity settling, and the smaller catalyst particles are separated by cyclone in the gas-solid separator 104. The fine-particle catalyst is transported to the filter 300 through the dust-containing gas pipeline 2 for thorough filtration. The fine-particle catalyst obtained by filtration is returned to the fluidized section of the fluidized bed reactor 100 through the catalyst reflux pipeline 4 for recycling. The clean reaction gas obtained enters the downstream fixed bed reactor 200 through the clean gas pipeline 3. The solid content in the clean reaction gas is 3 mg / Nm 3 ;

[0044] (4) Secondary reaction: The product gas obtained from step (3) leaves the filter 300 and enters the fixed bed reactor 200 through the clean gas pipeline 3 for a second hydrogenation reaction to achieve a high conversion efficiency.

[0045] In addition, the top pressure of the fluidized bed reactor 100 is 2.0 Mpa, and the top temperature is 175 °C. The fixed bed reactor 200 operates adiabatically. The conversion rate of dimethyl oxalate in the fluidized bed reactor 100 is 84%. The total conversion rate of total nitrite esters in the two reactors is 99%, and the selectivity for producing ethylene glycol is 97.5%.

[0046] Example 2:

[0047] As Figure 1 shown, this example corresponds to a production capacity of 300,000 tons of ethylene glycol. The reaction device for producing ethylene glycol by hydrogenating diethyl oxalate includes a fluidized bed reactor 100 and a fixed bed reactor 200. The fluidized bed reactor 100 is located upstream of the fixed bed reactor 200, that is, a fixed bed reactor is connected in series behind the fluidized bed reaction. The diameter of the fluidized bed reactor is 3.25 meters and the height is 15 meters. The diameter of the fixed bed reaction is 2.25 meters and the height is 6 meters. At the same time, a filter 300 is also connected between the fluidized bed reactor 100 and the fixed bed reactor 200 through the dust-containing gas pipeline 2 and the clean gas pipeline 3 to achieve gas-solid separation. The material of this filter is a stainless steel metal particle sintered microporous tube, which can effectively filter and separate fine particle catalysts. The fluidized bed reactor 100 includes catalyst a101, with a loading amount of 15 m 3 , a gas distributor 102, heat exchange tubes 103 and a gas-solid separator 104. The particle size of catalyst a101 is between 50 - 350 microns. The gas distributor a102 is an orifice plate distributor. The heat exchange tubes are made of stainless steel tubes, with a total area of 300 m 2 . The diameter of the heat exchange tubes is 50 mm and the length is 6 meters. There are 300 heat exchange tubes in parallel. The fixed bed reactor 200 is filled with catalyst b201 and a gas distributor b202. The catalyst b201 is a circular ring catalyst with a diameter of 6 mm, a ring wall thickness of 1.5 mm, a ring height of 6 mm, and a loading amount of 15 m 3 ; It also includes a steam drum 400, which is connected to the heat exchange tubes 103 in the fluidized bed reactor 100 through the water inlet pipeline 8 and the water outlet pipeline 9, and can produce 8.5 tons / hr of steam. The fixed bed reactor 200 is an adiabatic reactor, and the catalyst b201 is a circular ring. The filter 300 is filled with filter tubes, and the filter tubes are microporous metal sintered tubes. The filter has three interfaces, which are respectively connected to the top of the upstream fluidized bed reactor 100 through the dust-containing gas pipeline 2, connected to the downstream fixed bed reactor 200 through the clean gas pipeline 3, and then connected to the lower part of the fluidized bed reactor 100 through the catalyst particle return pipeline 4. The recovered fine particle catalysts are returned to the fluidized bed reaction.

[0048] The reaction process for producing ethylene glycol by hydrogenating diethyl oxalate according to the above device includes the following steps:

[0049] (1) First - order reaction: The feed gas enters the lower cavity of the fluidized - bed reactor 100 through the feed - gas inlet pipe 1, and is evenly distributed by the gas distributor a102, then enters the fluidized section containing the catalyst a101, contacts with the catalyst a101 to carry out the reaction of hydrogenating diethyl oxalate to ethylene glycol, generating ethylene glycol and co - producing ethanol. The volume composition of the feed gas is: diethyl oxalate = 3.3%, and the rest is hydrogen;

[0050] (2) Heat removal: On the one hand, the heat released by the hydrogenation reaction increases the temperature of the reaction gas from 40°C to the temperature of the fluidized - bed reactor 100, 190°C. On the other hand, through the heat exchange between the reaction gas and the heat - exchange tube 103, the excess reaction heat is removed, and a water cycle is formed with the steam drum 400 through the inlet water pipeline 8 and the outlet water pipeline 9. Steam is produced in the steam drum 400, and the steam production is 8.5 tons / hr, which is discharged from the steam product pipeline 7. Fresh desalted and deoxygenated soft - water total inlet pipeline 6 adds water to the steam drum to maintain the stable liquid level of the steam drum;

[0051] (3) Gas - solid separation: The reaction gas obtained from the hydrogenation reaction in step 2 enters the upper space of the fluidized - bed reactor 100. Larger - sized catalyst particles entrained by the reaction gas are separated by gravity sedimentation, and smaller - sized catalyst particles are separated by a cyclone in the gas - solid separator 104. Fine - sized catalyst particles are transported by the dust - containing gas pipeline 2 to the filter 300 for thorough filtration. The fine - particle catalyst obtained by filtration returns to the fluidized section of the fluidized - bed reactor 100 through the catalyst return pipeline 4 for recycling. The clean reaction gas enters the downstream fixed - bed reactor 200 through the clean - gas pipeline 3. The solid content in the clean reaction gas is 2.5mg / Nm 3 ;

[0052] (4) Second - order reaction: The product gas obtained from step (3) leaves the filter 300 and enters the fixed - bed reactor 200 through the clean - gas pipeline 3 for the second hydrogenation reaction to achieve a high conversion efficiency.

[0053] In addition, the top pressure of the fluidized - bed reactor 100 is 2.5Mpa, and the top temperature is 190°C. The fixed - bed reactor 200 operates adiabatically; the conversion rate of diethyl oxalate in the fluidized - bed reactor 100 is 88%, the total conversion rate of diethyl oxalate in the two reactors is 98.5%, and the selectivity for generating ethylene glycol is 98.5%.

[0054] Example 3

[0055] The particle size of the catalyst a is between 20 - 250 microns, and the particle size of the catalyst b is a sphere with a diameter of 2mm.

[0056] The top pressure of the fluidized bed reactor 100 is 5.5 Mpa, the top temperature is 200 °C, and the rest is the same as in Example 1.

[0057] The conversion rate of diethyl oxalate in the fluidized bed reactor 100 is 90%, the total conversion rate of diethyl oxalate in the two reactors is 99.3%, and the selectivity for producing ethylene glycol is 96.5%.

[0058] Example 4

[0059] The particle size of the catalyst a is between 850 and 1000 microns, and the particle size of the catalyst b is a 10 mm cylinder.

[0060] The top pressure of the fluidized bed reactor 100 is 1.5 Mpa, the top temperature is 160 °C, and the rest is the same as in Example 1.

[0061] The conversion rate of diethyl oxalate in the fluidized bed reactor 100 is 89.5%, the total conversion rate of diethyl oxalate in the two reactors is 98.7%, and the selectivity for producing ethylene glycol is 97.6%.

Claims

1. A reaction process for the hydrogenation of oxalate ester to ethylene glycol, characterized in that, the device used includes a fluidized bed reactor (100), a fixed bed reactor (200), a filter (300) and a steam drum (400). The bottom of the fluidized bed reactor (100) is connected to a raw gas inlet pipe (1), the top is connected to the filter (300), the filter (300) is connected to the fixed bed reactor (200), and the steam drum (400) is connected to the fluidized bed reactor (100) through a circulation pipeline; the fluidized bed reactor (100) includes a bottom gas distribution area, an intermediate reaction area, and a top gas-solid separation area. A gas distributor a (102) is provided in the gas distribution area, a catalyst a (101) and heat exchange tubes (103) are filled in the intermediate reaction area, and a gas-solid separator (104) is provided in the gas-solid separation area; the heat exchange tubes (103) form a circulation loop with the steam drum (400) through a water inlet pipeline (8) and a water outlet pipeline (9); Multiple parallel heat exchange tubes (103) are uniformly arranged in the reaction area, and the catalyst a (101) is filled between the heat exchange tubes; The reaction process for the hydrogenation of oxalate ester to ethylene glycol using the above device includes the following steps: (1) Primary reaction: The raw gas enters the lower cavity of the fluidized bed reactor (100) through the raw gas inlet pipe (1), and after being evenly distributed by the gas distributor a (102), it enters the fluidized section containing the catalyst a (101), contacts the catalyst a (101) and undergoes a catalytic reaction for the hydrogenation of oxalate ester to ethylene glycol, generating ethylene glycol and co-producing methanol or ethanol; (2) Heat removal: The heat released by the hydrogenation reaction in the fluidized bed reactor (100) raises the temperature of the reaction gas to a set temperature, and the excess heat is removed through the heat exchange tubes (102) and transported to the steam drum (400), where steam is produced in the steam drum (400); (3) Gas-solid separation: The reaction gas obtained from the hydrogenation reaction in the fluidized bed reactor (100) enters the upper gas-solid separation area for gas-solid separation, and then is transported to the filter (300) through a dust-containing gas pipeline (2) for thorough filtration. The fine particle catalyst obtained by filtration returns to the fluidized section of the fluidized bed reactor (100) through a catalyst particle return pipeline (4) for recycling, and the clean reaction gas obtained enters the downstream fixed bed reactor (200) through a clean gas pipeline (3); (4) Secondary reaction: The clean reaction gas undergoes a second hydrogenation reaction in the fixed bed reactor (200) to achieve a high conversion efficiency.

2. A reaction process for the hydrogenation of oxalate ester to ethylene glycol according to claim 1, characterized in that, the particle size of the catalyst a (101) is between 20 and 1000 microns.

3. A reaction process for the hydrogenation of oxalate ester to ethylene glycol according to claim 2, characterized in that, the particle size of the catalyst a (101) is between 50 and 500 microns.

4. A reaction process for the hydrogenation of oxalate ester to ethylene glycol according to claim 1, characterized in that, The fixed bed reactor (200) is filled with catalyst b (201) and gas distributor b (202), and the particle size of the catalyst b (201) is between 2 and 10 millimeters.

5. The reaction process for hydrogenating oxalate ester to ethylene glycol according to claim 4, characterized in that the particle size of the catalyst b (201) is between 4 and 8 millimeters.

6. The reaction process for hydrogenating oxalate ester to ethylene glycol according to claim 4, characterized in that the fixed bed reactor (200) is an adiabatic reactor, and the catalyst b (201) is spherical, cylindrical, annular or porous cylindrical.

7. The reaction process for hydrogenating oxalate ester to ethylene glycol according to claim 6, characterized in that the catalyst b (201) is annular.

8. The reaction process for hydrogenating oxalate ester to ethylene glycol according to claim 1, characterized in that the filter (300) is filled with filter tubes, which are microporous metal sintered tubes, ceramic tubes, glass fiber cloth bags or organic polymer fiber cloth bags, and are provided with three interfaces, which are respectively connected to the top of the upstream fluidized bed reactor (100) through the dust-containing gas pipeline (2), connected to the downstream fixed bed reactor (200) through the clean gas pipeline (3), and then connected to the lower part of the fluidized bed reactor (100) through the catalyst particle reflux pipeline (4).

9. The reaction process for hydrogenating oxalate ester to ethylene glycol according to claim 1, characterized in that the volume composition of the raw material gas entering the fluidized bed reactor (100) in step (1) is 1-5% of oxalate ester, and the rest is hydrogen; the oxalate ester is dimethyl oxalate or diethyl oxalate; the top pressure of the fluidized bed reactor (100) is 1.5-5.5 Mpa, and the top temperature is 160-200 °C.

10. The reaction process for hydrogenating oxalate ester to ethylene glycol according to claim 1, characterized in that The solid content in the clean reaction gas entering the fixed-bed reactor (200) after gas-solid separation in step (3) is less than 5 mg / Nm 3 ; The fixed-bed reactor (200) operates adiabatically; the conversion rate of oxalate ester in the fluidized bed reactor (100) is 80-90%, and the total conversion rate of oxalate ester in the two reactors is between 95-99%.

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