A reactor for synthesizing carbonic acid ester, a system for synthesizing carbonic acid ester, and a method

Abstract

The application discloses a reactor for synthesizing carbonates, a system for synthesizing carbonates and a method, the reactor comprising N reaction sections, N>=2, the reaction sections being sequentially arranged from top to bottom as a first reaction section, a second reaction section,..., and an Nth reaction section; wherein a coil is arranged in the first to (N-1)th reaction sections, and a cooling section is independently arranged below each of the first to (N-1)th reaction sections; each of the reaction sections independently comprises an upper wire mesh, a catalyst bed, a gas distributor and a lower wire mesh. A reaction system for synthesizing carbonates comprises a material mixer, the reactor and a heat removal system. The reactor and the reaction system mainly solve the problems of poor temperature control sensitivity, easy temperature rise, large liquid circulation amount and reaction heat removal lag in the existing carbonate production device, can be applied to industrialized production of carbonates and has good practicability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of carbonate synthesis, and particularly relates to a reactor for synthesizing carbonates, a system for synthesizing carbonates, and a method. BACKGROUND

[0002] Carbonates are very important organic compounds in industry, and have broad market prospects. Important carbonates in industry include dimethyl carbonate, diphenyl carbonate, ethylene carbonate, and propylene carbonate. These carbonates are widely used in engineering plastics-polycarbonate and polyurethane pigments, lithium ion battery electrolyte solvents, organic solvents, fuel additives, and alkylating agents and acylating agents.

[0003] At present, the main methods for synthesizing carbonates that have been industrialized at home and abroad are phosgene method, ester exchange, halogenated alcohol method, ethylene and carbon dioxide synthesis method, and oxirane and carbon dioxide synthesis method. The phosgene method is the earliest method for preparing carbonates, and this process has a long process flow, low yield, and serious pollution with trace amounts of organic chlorides, and is thus eliminated; the halogenated alcohol method requires a high temperature, and carbonates will decompose at high temperatures, thus causing high raw material consumption and many by-products, and the method is not industrialized; the ethylene and carbon dioxide synthesis method requires high pressure, and has explosion hazards and is not easy to industrialize.

[0004] In the reaction of oxirane and carbon dioxide to generate carbonates, a large amount of heat is released in the process of generating carbonates from oxirane and carbon dioxide. If the heat cannot be removed in time, the temperature will rise, the carbonates will decompose, and the catalyst will also be easily deactivated, causing the yield of the product to decrease. Therefore, strict and timely control of the temperature rise in the reaction process is crucial to the reaction.

[0005] CN109647134A discloses a multi-stage serial bubble bed-transport bed stacked CO2 adsorption reactor and method. The reactor includes a wind chamber, a central wind pipe, a riser, and a bubble bed. The bubble bed includes a wind distribution plate, on which CO2 adsorbent is prevented, the central wind pipe is provided in the middle of the wind distribution plate at the bottom, the riser is provided in the wind distribution plate at the bottom, and the water cooling coil is provided in the dense phase zone in each bubble bed. According to the claims, the CO2-containing flue gas enters from the side of the wind chamber, passes through the first wind distribution plate at the bottom to enter the first bubble bed, fluidizes the CO2 adsorbent in the first bubble bed, and at the same time, the decarburization reaction occurs; at the same time, the first water cooling disc operates to absorb the reaction heat in the first bubble bed, and stabilizes the carbonation reaction temperature in the first bubble bed. Since the process is a gas-solid phase reaction, the water cooling coil is used to remove the heat in the gas phase material, the efficiency is low, and it is not suitable for removing the heat in the strong exothermic system, which is not conducive to the wide application of the process.

[0006] CN1371900A discloses a method and a reactor for preparing propylene carbonate or ethylene carbonate. The method fills the catalyst into a reactor with heat removal device and separates the reaction zone from the product zone, in which heat can be removed while the reaction is taking place, avoiding high temperature deactivation of the catalyst and prolonging the service life of the catalyst. However, in the method, the material is prone to uneven distribution, the reaction is more intense near the catalyst loading device, the reaction is slow or does not occur near the catalyst loading device, and when the heat is not removed in time, it is more likely to cause local temperature rise, causing deactivation of the catalyst and affecting the reaction.

[0007] CN106478583A discloses a synthesis method of ethylene carbonate. The process mainly includes a one-stage synthesis reactor, a two-stage synthesis reactor, etc. In the synthesis method, in the one-stage synthesis reactor, ethylene oxide is in countercurrent contact with unreacted carbon dioxide in the two-stage reactor; in the two-stage synthesis reactor, the reaction product is in countercurrent contact with fresh carbon dioxide. In the synthesis process, external circulation is mainly used for heat removal, which requires a large amount of liquid circulation, and the control of temperature rise in the reactor is relatively lagging, which is not conducive to the reaction. SUMMARY

[0008] In order to overcome the problems in the prior art, the present application provides a reactor for synthesizing carbonates, a system for synthesizing carbonates and a method, which mainly solves the problems of temperature control insensitivity, easy temperature rise, large liquid circulation amount (the existing device has a large liquid circulation amount and a large circulation ratio of 10-30), and reaction heat removal lag in the existing carbonate production device, and can be applied to industrial production of carbonates, having good practicality.

[0009] One of the purposes of the present application is to provide a reactor for synthesizing carbonates, which comprises N reaction stages, N≥2, the reaction stages being sequentially from top to bottom the first reaction stage, the second reaction stage, …, the Nth reaction stage; wherein a coil is arranged in the first to (N-1)th reaction stages, and a cooling stage is independently arranged below each of the first to (N-1)th reaction stages.

[0010] Unlike external circulation cooling, the present application integrates the reaction stage and the cooling stage in the reactor, one cooling stage and one reaction stage above it forming an integrated unit; by integrating the cooling stage in the reactor, internal heat removal can reduce the amount of external circulation and the impact of too large circulation amount on the gas-liquid-solid flow field in the reactor. No cooling stage is arranged after the Nth reaction stage, and no coil is arranged in the Nth reaction stage.

[0011] In a preferred embodiment, no coil is arranged in the Nth reaction stage, and / or no cooling stage is arranged in the Nth reaction stage.

[0012] In the present application, since the reaction is mainly concentrated in the front reaction section, the reactants are basically consumed as the reaction goes further, and thus the amount of heat released is small, so that no coil or heat exchanger or other heat removal measures can be provided in the Nth reaction section.

[0013] In a preferred embodiment, each reaction section independently comprises an upper wire mesh, a catalyst bed, a gas distributor, and a lower wire mesh.

[0014] In a further preferred embodiment, the catalyst bed is disposed between the upper wire mesh and the lower wire mesh, and the gas distributor is disposed at the lower part of the catalyst bed.

[0015] In the present application, the catalyst is intercepted by the upper wire mesh and the lower wire mesh and does not flow out with the reaction products, and thus the catalyst does not need to be separated by distillation or other means (which would increase energy consumption), but only needs to be separated from the reactants and reaction products by the physical method of interception by the wire mesh.

[0016] In a preferred embodiment, the volume between the upper wire mesh and the lower wire mesh is greater than the wet volume of the catalyst.

[0017] In a further preferred embodiment, the volume between the upper wire mesh and the lower wire mesh is 1.2-2 times the wet volume of the catalyst.

[0018] For example, the volume between the upper wire mesh and the lower wire mesh is 1.2 times, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, or 2 times the wet volume of the catalyst.

[0019] Most of the prior art uses homogeneous catalysts, i.e. liquid catalysts, which do not expand. The present application uses heterogeneous catalysts, i.e. solid catalysts, which do not flow out of the reactor with the reaction products, and thus do not require additional measures for separating the catalyst and additional energy consumption. After expansion, the catalyst particles increase in size, which is more conducive to the interception of the catalyst particles in the bed of the reaction section (because the smaller the catalyst particles, the smaller the pore size of the interception wire mesh, and the greater the resistance when the fluid passes through).

[0020] In a preferred embodiment, the coil is disposed in the catalyst bed.

[0021] In the present application, the catalyst is suspended in the bed, and thus the coil can be used in the reaction bed to remove heat from the catalyst bed in a timely manner.

[0022] This invention incorporates a heat dissipation coil within the reaction section, significantly reducing the circulation volume of existing equipment. This is because the reaction between alkyl oxidants (e.g., ethylene oxide) and carbon dioxide is exothermic, and the catalyst has specific temperature requirements; excessive temperature increases would negatively impact catalyst activity. Therefore, the heat dissipation coil within the reaction section drastically reduces the circulation volume. Excessive circulation volume places higher demands on the circulation pump and negatively affects the fluid flow within the reactor, impacting mass and heat transfer.

[0023] In a further preferred embodiment, the coil is disposed above the gas distributor.

[0024] In a further preferred embodiment, the coil uses saturated hydrothermal heating at a temperature of 100-150°C (e.g., 100°C, 110°C, 120°C, 130°C, 140°C, or 150°C), preferably 100-120°C; the saturated hot water is vaporized after heat removal, and the vaporization rate is preferably 5%-40%.

[0025] In this process, saturated water is preferably used as the heat removal medium within the reaction section because the suitable temperature for the catalyst described in this invention is 60-150℃. Temperatures that are too low or too high will affect the catalyst's activity. Using saturated water for heat removal prevents excessive temperature fluctuations within the reaction section, maintaining a stable temperature. Specifically, saturated hot water has a high enthalpy of vaporization, enabling rapid and effective removal of the heat of reaction from the catalyst bed. Furthermore, the saturated hot water at this temperature does not cool the catalyst bed to a lower temperature, ensuring the reaction operates normally within a reasonable temperature range.

[0026] In a preferred embodiment, the cooling section is a shell-and-tube heat exchanger.

[0027] In a further preferred embodiment, the reaction liquid flows through the tube side, and the cooling medium flows through the shell side; preferably, the cooling medium is water at 70-90°C, which is also used to remove heat from the reactor while ensuring the reaction feed temperature.

[0028] In a preferred embodiment, a feed inlet for raw material I is provided above the first reaction section from top to bottom. Preferably, the raw material I is an alkylene oxide, such as ethylene oxide.

[0029] In a further preferred embodiment, a feed inlet for raw material II is provided below the first to (N-1) reaction sections. Preferably, the raw material II is carbon dioxide.

[0030] In this way, the raw material II is fed into the lower part of the reactor in one or more streams, and is uniformly distributed by the gas distributor after entering the reactor. The reactor adopts a countercurrent feeding mode, and the inventors have found through a large number of studies that, for the conversion effect under the same conditions, the conversion rate of countercurrent is higher than that of parallel flow. Laboratory data shows that the conversion rate of countercurrent is 5-10% higher than that of parallel flow.

[0031] In a preferred embodiment, a reactant outlet is arranged at the bottom of the reactor; and / or, a non-condensable gas outlet is arranged at the top of the reactor.

[0032] The reactor is provided with a coil and timely heat removal of the cooling section, which can effectively solve the problem of large amount of circulating material.

[0033] In a further preferred embodiment, an external pipeline and a circulating pipeline are further arranged at the bottom of the reactor and connected with the outlet.

[0034] In a still further preferred embodiment, one end of the circulating pipeline is connected with the outlet of the reactor, and the other end is connected with the raw material I feeding pipeline.

[0035] Part of the product is circulated back into the reactor to control or adjust the concentration of the raw material ethylene oxide.

[0036] In this way, part of the outlet material at the bottom of the reactor is circulated back into the reactor inlet through the material mixer, and part is taken out as the reaction product; preferably, the circulating pipeline does not pass through the heat exchange equipment. Preferably, the circulating product is mixed with the raw material I before entering the reactor, because in the preparation of carbonates, the raw material I is epoxy, which is active in chemical properties. After mixing, the epoxy concentration is uniform, the reaction heat is also uniform, and the phenomenon of local high temperature is avoided.

[0037] In a still further preferred embodiment, a circulating pump is arranged on the circulating pipeline.

[0038] The second object of the present application is to provide a reaction system for synthesizing carbonates, comprising a material mixer, a reactor and a heat removal system, wherein the reactor adopts the reactor of the first object of the present application.

[0039] In a preferred embodiment, the reaction system comprises a raw material I feeding pipeline connected with the raw material I feeding port of the reactor.

[0040] In a further preferred embodiment, the material mixer is arranged at the intersection of the raw material I feeding pipeline and the circulating pipeline, and communicates with the two pipelines.

[0041] The raw material I and the circulating outlet material enter the material mixer together, and then enter the reactor through the raw material I feeding port of the reactor.

[0042] In a preferred embodiment, the heat removal system is a steam generator.

[0043] In a further preferred embodiment, the outlet of the steam generator is connected to the inlet of the coil, and the inlet of the steam generator is connected to the outlet of the coil.

[0044] In a still further preferred embodiment, the saturated water of the steam generator enters the catalyst bed coil by siphon.

[0045] In a preferred embodiment, the concentration of the raw material I at the raw material I inlet of the reactor is less than 30%, preferably less than 15%. Wherein, the concentration is based on the total concentration of the raw material I and the circulating material being 100wt%.

[0046] Wherein, reducing the concentration of the raw material I (e.g. alkylene oxide) at the inlet of the reactor can prevent a large amount of heat generated by the reaction of the raw material I, causing the temperature of the catalyst bed to rise rapidly.

[0047] A third object of the present application is to provide a method for synthesizing carbonates, which is performed by using the reactor according to the first object of the present application or the system according to the second object of the present application, the method comprising: feeding the raw material I into the reactor from the raw material I inlet of the reactor, feeding the raw material II into the reactor from the raw material II inlet of the first to (N-1)th reaction sections, and performing a reverse contact reaction between the raw material I and the raw material II, discharging from the discharge outlet of the reactor, and recycling part of the discharge to the mixer to mix with the raw material I and then feeding into the reactor.

[0048] In a preferred embodiment, the raw material I is an alkylene oxide, preferably ethylene oxide; and / or, the raw material II is carbon dioxide.

[0049] In a further preferred embodiment, the molar flow ratio of the raw material I to the raw material II is 1:(1.01-2), preferably 1:(1.05-1.5).

[0050] For example, the molar flow ratio of the raw material I to the raw material II is 1:1.01, 1:1.05, 1:1.1, 1:1.15 or 1:2.

[0051] In a preferred embodiment, the catalyst is selected from at least one of a resin-based catalyst, a halide-based catalyst, and a complex-based catalyst.

[0052] Wherein, the catalyst is not particularly limited as long as it can achieve the reaction.

[0053] In a preferred embodiment, the coil pipe adopts saturated hot water with a temperature of 100-150℃ (for example, 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃), preferably 100-120℃; the saturated hot water is vaporized after heat removal, and the vaporization rate is preferably 5%-40%.

[0054] In a preferred embodiment, in the cooling section of the column tube heat exchanger, the reaction liquid passes through the tube side, and the cooling medium passes through the shell side; preferably, the cooling medium is water with a temperature of 70-90℃, and the cooling medium with such a temperature is also used to remove the heat in the reactor while ensuring the temperature of the reaction feed.

[0055] In a preferred embodiment, the reaction pressure is 2-10MPaG, preferably 2-5MPaG.

[0056] For example, the reaction pressure is 2MPaG, 2.5MPaG, 3MPaG, 3.5MPaG, 4MPaG, 4.5MPaG or 5MPaG.

[0057] In a preferred embodiment, the concentration of the raw material I at the raw material I feeding port of the reactor is controlled to be less than 30wt%, preferably less than 15%.

[0058] In this way, the decrease of the concentration of the raw material I (for example, alkyl oxide) at the inlet of the reactor can prevent the reaction of a large amount of raw material I to release heat, causing the temperature of the catalyst bed to rise rapidly.

[0059] In the present application, the CO2 flow rate gradually decreases from the first reaction section to the Nth reaction section; preferably, 70-95% of the CO2 enters the first reaction section, and the rest enters the subsequent reaction sections, and the CO2 flow rate gradually decreases from the second reaction section to the Nth reaction section in the subsequent reaction sections.

[0060] The endpoints of the ranges and any numerical values included in the present application are not limited to the precise values stated herein and include values approximating these. For ranges, endpoints are understood as being independently combinable and interchangeable with individual points and ranges, such that the disclosure includes new ranges created by combining the endpoints with the individual points and ranges. In the following, the technical solutions can be combined with each other to obtain new technical solutions, which should also be considered as being specifically disclosed herein.

[0061] Compared with the prior art, the present application has the following beneficial effects: the present application mainly solves the problems of poor temperature control, easy temperature rise, large liquid circulation amount and reaction heat removal lag in the existing carbonate production device, and can be applied to the industrial production of carbonates. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 Structure diagram of the system of the present application (where N=3) is shown.

[0063] Figure 1 In the figure, I is the material mixer, II is the first reaction section, III is the first cooling section, IV is the second reaction section, V is the second cooling section, VI is the third reaction section, VII is the circulating pump, and VIII is the heat removal system.

[0064] In the reaction stream, 1 is the raw material I (for example, alkylene oxide), 2 is CO2, 3 is non-condensable gas (mainly CO2), 4 is the crude product, and 5 is the circulating material.

[0065] The process flow of the system for synthesizing carbonic acid ester of the present application is described as follows, where the raw material I is ethylene oxide and the raw material II is CO2:

[0066] The raw material ethylene oxide 1 is mixed with the reacted circulating material 5 in the material mixer I and then enters the first reaction section. CO2 is metered and then enters the first reaction section from the bottom and another stream of CO2 enters from the bottom of the second reaction section. In the first reaction section, ethylene oxide reacts with CO2. The reaction heat is removed by the coil in the reactor and then enters the second reaction section after heat exchange in the first cooling section. Similarly, the reaction material in the second reaction section continues to react, and part of the heat is removed by the coil and then enters the third reaction section after heat exchange in the second cooling section. In the third reaction section, no CO2 is introduced and the reaction with dissolved CO2 continues. The material after the reaction in the third reaction section is mixed with the raw material ethylene oxide 1 by the circulating pump, which can reduce the temperature rise of the bed in each reaction section and effectively remove heat. Another stream is taken out as the crude product for subsequent separation.

[0067] Figure 2 Structure diagram of the reaction section is shown.

[0068] 11 - bottom wire mesh, 12 - gas distributor, 13 - heat removal coil, 14 - upper wire mesh, and 15 - catalyst bed. DETAILED DESCRIPTION

[0069] The present application is specifically described below in combination with specific examples. It is necessary to point out that the following examples are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application. Some non-essential improvements and adjustments of the present application made by those skilled in the art based on the content of the present application still fall within the protection scope of the present application.

[0070] It should be further noted that each of the technical features described in the following detailed description can be combined with any other technical features in any suitable manner, without contradiction. In order to avoid unnecessary repetition, the present application will not describe each possible combination.

[0071] Furthermore, any combination of the various embodiments of the present application can be made, as long as it does not contradict the idea of the present application, and the technical solution thus formed is part of the original disclosure of the present specification and falls within the protection scope of the present application.

[0072] The raw materials used in the examples and comparative examples, if not specifically limited, are publicly known in the art, for example, can be directly purchased or prepared according to the publicly known preparation methods.

[0073] Example 1

[0074] The system shown in Fig. 1 is used, wherein the volume between the upper wire mesh and the lower wire mesh is 1.8 times the wet volume of the catalyst: Figure 1 The 100 kmol / h of ethylene oxide is metered and mixed with the circulating material at the outlet of the reactor in a material mixer, and then enters the top of the first reaction section, and the concentration of ethylene oxide at the raw material I inlet of the reactor is controlled to be 18%. The CO2 flow is 120 kmol / h, of which 100 kmol / h enters the bottom of the first reaction section, and the other part of 20 kmol / h enters the bottom of the second reaction section, and the reaction pressure is 2.5 MPaG. A part of the heat is removed by using 100 ℃ saturated liquid in the reactor, and the cooling section uses 70 ℃ water. The reaction material of the previous reaction section is cooled to 90 ℃ by the cooling section and then enters the next reaction section.

[0075] The outflow from the third reaction section is 65% of the circulating material for heat removal, and the rest is taken out as the product. In this way, the reaction heat removal in the reactor is timely, the temperature rise is not more than 20 ℃, which can well ensure the progress of the reaction, and the conversion rate of ethylene oxide is not less than 85%.

[0076] Example 2

[0077] The present embodiment is the same as example 1, except that 110 ℃ saturated hot water is used in the reactor to remove a part of the heat in the reactor. In this way, the reaction temperature in the reactor is higher than that in example 1, but the conversion rate of ethylene oxide is slightly improved and is not less than 90%.

[0078] Example 3

[0079]

[0080] ​The process is the same as example 1, except that 120°C saturated hot water is used to remove part of the heat in the reactor, and 70% of the material is recycled to remove the heat. In this way, the temperature rise in the reactor is not more than 10°C, and the conversion of ethylene oxide is not less than 93%.

[0081] [Example 4]

[0082] The process is the same as example 1, except that 75% of the material is recycled to remove the heat. In this way, the temperature rise in the reactor is not more than 15°C, and the conversion of ethylene oxide is not less than 83%.

[0083] [Example 5]

[0084] The process is the same as example 1, except that 80 kmol / h of CO2 is fed into the bottom of the first reactor, and another 40 kmol / h is fed into the bottom of the second reactor. In this way, the temperature rise in the first reactor is increased by 5°C, and the total conversion of ethylene oxide is not less than 88%.

[0085] [Comparative Example 1]

[0086] The process of example 1 is repeated, except that CO2 is fed as a single stream, and is fed with ethylene oxide from the top of the first reaction stage. The total conversion of EO is ≤ 85%, and the feed ratio of raw material CO2 to ethylene oxide is < 1.1. In this case, the CO2 that participates in the reaction is reduced (the ratio of CO2 to ethylene oxide is reduced), and the conversion of EO is reduced.

[0087] [Comparative Example 2]

[0088] The process of example 1 is repeated, except that CO2 is fed as a single stream, i.e. from the bottom of the first reaction stage. The total conversion of EO is ≤ 85%, and the feed ratio of raw material CO2 to ethylene oxide is < 1.15. In this case, the CO2 that participates in the reaction is reduced (the ratio of CO2 to ethylene oxide is reduced), and the conversion of EO is reduced.

[0089] [Comparative Example 3]

[0090] The process of example 1 is repeated, except that the entire output is taken out without recycling. The temperature rise in the first reaction stage is ≥ 25°C.

[0091] The present application has been described in detail with reference to specific embodiments and illustrative examples, but these are not to be construed as limiting the application. Those skilled in the art will understand that various equivalents to the technical solutions and embodiments of the present application can be made without departing from the spirit and scope of the present application, and these all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims.

Claims

1. A method for synthesizing carbonates, carried out in a reactor, the reactor comprising N reaction sections, N≥2, the reaction sections being sequentially from top to bottom a first reaction section, a second reaction section,..., an Nth reaction section; wherein, Coils are arranged in the 1st to (N-1)th reaction sections, and cooling sections are arranged below the 1st to (N-1)th reaction sections, the cooling sections being column tube heat exchangers, and the cooling medium being water at 70-90°C; each reaction section independently comprises an upper wire mesh, a catalyst bed, a gas distributor and a lower wire mesh, and the coils are arranged in the catalyst bed; a raw material I inlet is arranged above the 1st reaction section, and the raw material I is an alkylene oxide; A raw material II inlet is arranged below the 1st to (N-1)th reaction sections, and the raw material II is carbon dioxide; the method comprises: the raw material I enters the reactor from the raw material I inlet of the reactor, the raw material II enters the reactor from the raw material II inlet of the 1st to (N-1)th reaction sections, the CO2 flow into the 1st to (N-1)th reaction sections is gradually reduced, the raw material I and the raw material II are reversely contacted and reacted, and the reaction system is discharged from a discharge port of the reactor, part of the outlet is taken out, and part of the discharge is circulated to the mixer, mixed with the raw material I and then enters the reactor; the raw material I is an alkylene oxide, the raw material II is carbon dioxide, a heterogeneous catalyst is used in the reaction section, and saturated water is used for heat exchange of the coils, and the temperature is 100-150°C.

2. The method according to claim 1, wherein, No coil is arranged in the Nth reaction section, and / or no cooling section is arranged in the Nth reaction section; and / or The catalyst bed is arranged between the upper wire mesh and the lower wire mesh, and the gas distributor is arranged below the catalyst bed.

3. The method of claim 2, wherein, The volume between the upper wire mesh and the lower wire mesh is greater than the wet catalyst volume.

4. The method of claim 2, wherein, The volume between the upper wire mesh and the lower wire mesh is 1.2-2 times the wet catalyst volume.

5. The method according to claim 2, wherein, The coil is arranged above the gas distributor.

6. The method of claim 2, wherein, The cooling section is a column tube heat exchanger, the reaction liquid passes through the tube, and the cooling medium passes through the shell.

7. The method according to one of claims 1 to 6, characterized in that A reaction material outlet is arranged at the bottom of the reactor, and / or a non-condensable gas outlet is arranged at the top of the reactor.

8. The method of claim 7, wherein, An external taking-out pipeline and a circulating pipeline connected with the discharge port are further arranged at the bottom of the reactor.

9. The method of claim 8, wherein One end of the circulating pipeline is connected with the discharge port of the reactor, and the other end is connected with the raw material I feeding pipeline.

10. The method of claim 1, carried out using a reaction system comprising a mass mixer, the reactor, and a heat removal system, wherein, The heat removal system is a steam generator, the outlet of the steam generator is connected with the inlet of the coil, the inlet of the steam generator is connected with the outlet of the coil, and saturated water of the steam generator enters the catalyst bed coil in a siphon manner.

11. The method of claim 10, wherein, The reaction system comprises a raw material I feeding pipeline connected with the raw material I inlet of the reactor.

12. The method of claim 11, wherein The material mixer is arranged at the intersection of the raw material I feeding pipeline and the circulating pipeline, and communicates with the two pipelines.

13. The method of claim 10, wherein, The concentration of the raw material I at the raw material I inlet of the reactor is controlled to be less than 30%, based on the total concentration of 100wt% of the raw material I and the circulating material.

14. The method of claim 13, wherein, The concentration of the raw material I at the raw material I inlet of the reactor is controlled to be less than 15%, based on the total concentration of 100wt% of the raw material I and the circulating material.

15. The method of claim 1, wherein, The raw material I is ethylene oxide.

16. The method of claim 1, wherein, The molar flow ratio of the raw material I to the raw material II is 1: (1.01-2).

17. The method of claim 1, wherein, The molar flow ratio of the raw material I to the raw material II is 1: (1.05-1.5).

18. The method of claim 1, wherein, The catalyst is selected from at least one of resin-based catalysts.

19. The method of claim 1, wherein, The coil uses saturated water heat, and the temperature is 100-120℃; and / or, The pressure of the reaction is 0.0-0.5 MPaG.

20. The method of any one of claims 11-13, wherein, The pressure of the reaction is 0.0-0.3 MPaG.

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