Reaction device for continuously preparing 2, 5-furandicarboxylic acid

Abstract

The utility model discloses a continuous preparation device of 2, 5-furandicarboxylic acid, which comprises a feeding unit, a carboxylation reactor, an esterification reactor, a discharged agent transfer tank and a returned agent transfer tank, wherein the feeding unit is used for inputting reaction raw materials; the carboxylation reactor is of a three-section structure and is connected with the feeding unit; the discharged agent transfer tank is connected with the carboxylation reactor and the esterification reactor through pipelines; the esterification reactor is connected with the discharged agent transfer tank; and the returning agent transfer tank is connected with the esterification reactor. Wherein the main bodies of the carboxylation reactor and the esterification reactor are composed of multiple layers of fluidized beds. According to the reaction device and method disclosed by the utility model, 2, 5-furandicarboxylic acid can be continuously synthesized from furoic acid, the reaction speed is greatly accelerated, the characteristic that a product and a catalyst are difficult to separate after salifying is avoided through the second-step esterification reaction, and the system efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical synthesis, and in particular relates to a low-cost continuous industrial reaction device for 2,5-furandicarboxylic acid. Background Art

[0002] 2,5-Furandicarboxylic acid, chemical formula is C 6 H 4 O 5 , the structural formula is As an important derivative of furan, it is similar in structure and chemical properties to petroleum-derived chemical terephthalic acid, and can replace p-xylene in the fields of polyester and polyamide, and is listed as one of the 12 bio-based platform chemicals by the U.S. Department of Energy. Therefore, the research on new processes for the efficient and green preparation of 2,5-furandicarboxylic acid is of great significance.

[0003] At present, the synthesis technology of 2,5-furandicarboxylic acid mainly includes the 5-hydroxymethylfurfural (HMF) route and the furoic acid route. The HMF route is to prepare HMF by hydrolysis of fructose and other raw materials, and obtain 2,5-furandicarboxylic acid by oxidation. The HMF route is the most promising route for the large-scale preparation of 2,5-furandicarboxylic acid, but there are still many problems. HMF is mainly a hydrolysis product of cellulose, and this process has not yet been industrialized. Therefore, 5-hydroxymethylfurfural has a small reserve and is difficult to prepare. In addition, the presence of aldehyde groups and hydroxymethyl groups in the structure makes it unstable, resulting in very high costs. In addition, when using HMF to oxidize 2,5-furandicarboxylic acid, it is necessary to use expensive precious metal catalysts. The oxidation often stays in the intermediate step, resulting in incomplete reaction, and the intermediate product is difficult to separate from 2,5-furandicarboxylic acid. At present, it is not suitable for large-scale industrial production, which greatly limits the application of 2,5-furandicarboxylic acid and its polyester products.

[0004] Some documents or patents report methods for preparing 2,5-furandicarboxylic acid using furancarboxylic acid as raw material. For example, Anaindeeta Banerjee reported in Nature Impurities that alkali metal carbonate molten salt system was used to catalyze the reaction of 5-hydroxymethylfurfural to produce 2,5-furandicarboxylic acid, among which cesium salt had the best catalytic activity and the product yield was close to 90%. The catalyst cost and product separation were two difficulties of this method. In patent CN 116283849 A, cesium furoate and cesium dicarboxylate (cesium malonate, cesium methylmalonate, cesium ethylmalonate, cesium 1,3-acetone dicarboxylate) are mixed evenly and placed in a reactor, and a cesium salt catalyst can be selectively added. Then, a solid-phase molten salt reaction is carried out under nitrogen or inert gas atmosphere, stirring, and pressurization to obtain an intermediate product cesium salt, which is then protonated and purified to obtain the final product 2,5-furandicarboxylic acid, but this method is difficult to achieve continuous production. Patent CN 117263890 A uses bicarbonate and carbonate to react for a certain period of time to prepare 2,5-furandicarboxylate, which is then protonated with an acid to obtain a precipitated product 2,5-furandicarboxylic acid. Patent CN 114450273 A adds an aqueous solution of potassium hydroxide and potassium acetate to furoic acid. The removal of water produced a white solid, which was then reacted with CO in an autoclave. 2 The yield of FDCA can reach 90% after 2 hours of reaction, but this method is also difficult to achieve continuous production.

[0005] Judging from the above existing technologies, most of them use traditional kettle reactions, and even face the problem of difficult separation of molten salt systems and products. Therefore, how to develop efficient and inexpensive routes for the preparation of 2,5-furandicarboxylic acid will be an important means of synthesizing biomass-derived bulk chemicals and high-value-added polymer materials, and has great application prospects and potential. Utility Model Content

[0006] Technical issues

[0007] In view of the problems existing in the prior art, one object of the utility model is to provide a device for continuously preparing 2,5-furandicarboxylic acid. The device is designed with a dual pressurized fluidized bed combined reaction device route for a two-step synthesis reaction. The combined reaction device consists of two main reactors and a catalyst circulation part. The two reactor bodies are composed of a multilayer fluidized bed. The two reactors are connected by a discharge pipe and a discharge transfer tank, and a return pipe and a return transfer tank. The method using the device uses furoic acid as a raw material and synthesizes 2,5-furandicarboxylic acid in two steps in the presence of an alkaline catalyst. First, furoic acid undergoes a carboxylation reaction in the presence of an alkaline catalyst to generate furandicarboxylate. The furandicarboxylate is attached to the catalyst surface in a solid form, and then the furandicarboxylate is further reacted with CO 2The dimethyl 2,5-furandicarboxylate is reacted with methanol to form dimethyl 2,5-furandicarboxylate. The dimethyl 2,5-furandicarboxylate is gaseous under the reaction conditions and is separated from the solid catalyst. The obtained dimethyl 2,5-furandicarboxylate is then acidified to form 2,5-furandicarboxylic acid.

[0008] Technical Solution

[0009] According to one aspect of the utility model, the utility model provides a device for continuously preparing 2,5-furandicarboxylic acid, comprising a feeding unit, a carboxylation reactor, an esterification reactor, a discharging agent transfer tank, and a returning agent transfer tank;

[0010] Wherein, the feeding unit is located on one side of the carboxylation reactor and is used for inputting reaction raw materials, and the raw materials are solid raw materials or liquid raw materials;

[0011] The carboxylation reactor is a three-stage structure, the upper part is a cylindrical structure, the middle part is an inverted cone structure, and the lower part is a cylindrical structure. The diameter of the upper cylindrical structure is greater than the diameter of the lower cylindrical structure, which is an expanded section. The upper and lower diameter ratios are 1.1:1 to 4:1, and the reactor is connected to form a whole through the inverted cone structure in the middle. The angle between the cone surface of the inverted cone structure in the middle and the vertical direction is 15°-45°.

[0012] The carboxylation reactor has at least one feed port, which is connected to the feed unit; a gas outlet is provided at the top for conducting out the gas phase tail gas; and a gas inlet is provided at the bottom for introducing CO into the reactor. 2 and a mixed gas of a carrier gas; the middle and lower part of the carboxylation reactor is used as the main reaction zone, wherein a single-stage or multi-stage horizontal distribution plate is arranged, which is used to carry the catalyst and distribute the gas, and the reaction process is divided into a number of corresponding reaction areas, and the catalysts filled on the distribution plates at each level can be the same or different; a funnel-shaped internal catalyst overflow pipe is arranged in the main reaction zone, which is used to make the catalyst in the carboxylation reactor flow from the upper layer to the lower layer; a catalyst outlet is arranged on the side of the lower part of the carboxylation reactor, and a catalyst inlet is arranged on the side of the middle and lower part of the carboxylation reactor;

[0013] The discharging transfer tank has a catalyst inlet and a catalyst outlet, the catalyst inlet is connected to the catalyst outlet of the carboxylation reactor through a pipeline, and the catalyst outlet of the discharging transfer tank is connected to the esterification reactor through a pipeline; the discharging transfer tank is a shell-and-tube structure, and the temperature inside the discharging transfer tank is adjusted by heat exchange of a heat exchange medium; the discharging transfer tank has an air inlet at the bottom and an exhaust gas outlet at the top, which are used to adjust the pressure inside the discharging transfer tank; before the catalyst enters the discharging transfer tank, the slide valve on the catalyst inlet and outlet delivery pipeline connected to the discharging transfer tank is closed, and its temperature and pressure are adjusted to be consistent with those of the carboxylation reactor, and then the slide valve on the connecting pipeline between the discharging transfer tank and the carboxylation reactor is opened, the catalyst enters the discharging transfer tank, and then the slide valve on the connecting pipeline between the discharging transfer tank and the carboxylation reactor is closed; the temperature and pressure inside the discharging transfer tank are adjusted to be consistent with those of the esterification reactor, and then the slide valve on the connecting pipeline between the discharging transfer tank and the esterification reactor is opened to transport the catalyst to the esterification reactor for further reaction.

[0014] The middle part of the esterification reactor is provided with a catalyst inlet, which is connected to the catalyst outlet of the catalyst outlet transfer tank through a pipeline to receive the circulating catalyst; the top is provided with a gas outlet for conducting out the gas phase mixture containing dimethyl 2,5-furandicarboxylate; the bottom is provided with a gas inlet for introducing CO into the reactor. 2 , a mixture of methanol and a carrier gas; the middle and lower part of the esterification reactor is used as the main reaction zone, wherein a single-stage or multi-stage horizontal distribution plate is arranged to carry the catalyst and distribute the gas, and the reaction process is divided into several corresponding reaction areas, and the catalysts filled on the distribution plates at each stage can be the same or different; a funnel-shaped internal catalyst overflow pipe is arranged in the main reaction zone to make the catalyst in the esterification reactor flow from top to bottom; a catalyst outlet is arranged on the side of the lower part of the esterification reactor;

[0015] The return agent transfer tank has a catalyst inlet and a catalyst outlet. The catalyst inlet of the return agent transfer tank is connected to the catalyst outlet of the esterification reactor through a pipeline to receive the circulated catalyst. The catalyst outlet of the return agent transfer tank is connected to the catalyst inlet of the carboxylation reactor through a pipeline to return the circulated catalyst to the carboxylation reactor. The return agent transfer tank is a shell and tube structure, and the temperature inside the return agent transfer tank is adjusted by heat exchange with a heat exchange medium. The return agent transfer tank has an air inlet at the bottom and an exhaust gas outlet at the top, which is used to adjust the temperature of the return agent transfer tank. Internal pressure; before the catalyst enters the return agent transfer tank, close the slide valve on the catalyst inlet and outlet delivery pipeline connected to the return agent transfer tank, adjust the internal temperature and pressure to be consistent with the esterification reactor, and then open the slide valve on the connection pipeline between the return agent transfer tank and the esterification reactor, the catalyst enters the return agent transfer tank, and then close the slide valve on the connection pipeline between the return agent transfer tank and the esterification reactor; adjust the temperature and pressure in the return agent transfer tank to be consistent with the carboxylation reactor, and then open the slide valve on the connection pipeline between the return agent transfer tank and the carboxylation reactor to transport the catalyst to the carboxylation reactor to complete a reaction cycle.

[0016] Preferably, the feeding unit comprises a silo and a feeder.

[0017] Furthermore, the feeder includes but is not limited to a screw feeder or a star feeder, and the feeder is directly connected to the feed port of the carboxylation reactor.

[0018] Preferably, when the reaction raw material is in liquid phase, i.e. molten furoic acid (temperature is higher than 150° C.), the feeding unit comprises a storage tank and a feeding pump;

[0019] Furthermore, when the reaction raw materials are in liquid phase, a liquid distributor is also provided in the upper cylindrical structure of the carboxylation reactor, and the liquid distributor includes but is not limited to a liquid distribution plate and an atomizing nozzle; the feed pump of the feed unit is connected to the feed port of the carboxylation reactor through a pipeline, and the reaction raw materials are transported to the liquid distributor.

[0020] Preferably, the gas outlet of the carboxylation reactor is connected to a filter, and the filter is used to remove solid particles in the gas phase tail gas.

[0021] Preferably, the gas outlet of the esterification reactor is connected to a filter, and the filter is used to remove solid particles in the gas phase mixture.

[0022] Preferably, the filter may include but is not limited to a screen with corresponding aperture, a cyclone separator, etc.

[0023] Preferably, a slide valve is provided on the pipelines connecting the catalyst inlet and the catalyst outlet of the catalyst outlet transfer tank to control the catalyst flow or the on-off of the pipeline.

[0024] Preferably, the pipelines connecting the catalyst inlet and the catalyst outlet of the return agent transfer tank are both provided with slide valves for controlling the catalyst flow or the on-off of the pipeline.

[0025] Preferably, an external catalyst overflow pipe is provided on the outer wall of the carboxylation reactor at a position corresponding to the internal catalyst overflow pipe position in the carboxylation reactor, and is also used to make the catalyst in the carboxylation reactor flow from top to bottom.

[0026] Preferably, an external catalyst overflow pipe is provided on the outer wall of the esterification reactor at a position corresponding to the internal catalyst overflow pipe position in the esterification reactor, and is also used to make the catalyst in the esterification reactor flow from top to bottom.

[0027] Preferably, the carboxylation reactor and the esterification reactor are fluidized bed reactors.

[0028] Preferably, the distribution plates provided in the carboxylation reactor and the esterification reactor include but are not limited to porous plates, sieve plates, bubble cap plates and the like.

[0029] Beneficial Effects

[0030] The reaction device of the utility model is aimed at the reaction process of generating 2,5-furandicarboxylic acid (FDCA) compound by carboxylation reaction of furoic acid. Through the combined design of the core fluidized bed reactor, the process of synthesizing 2,5-furandicarboxylic acid from furoic acid is disassembled from the traditional intermittent kettle reaction into a two-step continuous reaction, which greatly accelerates the reaction speed. The second step esterification reaction avoids the difficulty of separating the product and the catalyst after salt formation, thereby improving the system efficiency. After the catalyst participates in the reaction, the separation cycle is directly completed in the reaction system, reducing the separation unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the drawings that are not necessarily drawn to scale, the same reference numerals may describe similar parts in different views. The same reference numerals with letter suffixes or different letter suffixes may represent different instances of similar parts. The accompanying drawings generally illustrate various embodiments by way of example and not limitation, and together with the specification and claims, are used to illustrate the embodiments of the utility model. When appropriate, the same reference numerals are used in all drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present device or method.

[0032] Figure 1The utility model is a schematic diagram of the structure of a process device for producing 2,5-furandicarboxylic acid compounds.

[0033] Figure 2 The utility model is a schematic diagram of the structure of a process device for producing 2,5-furandicarboxylic acid compounds.

[0034] Figure 3 The utility model is a schematic diagram of the structure of a process device for producing 2,5-furandicarboxylic acid compounds.

[0035] Figure 4 The utility model is a schematic diagram of the structure of a process device for producing 2,5-furandicarboxylic acid compounds.

[0036] Reference numerals:

[0037] 1-Feeding system: 11-silo / storage tank, 12-feeder / feeding pump;

[0038] 2-carboxylation reactor: 20 / 20-1-feed port, 20-1-liquid distributor, 21-gas inlet, 22-gas outlet, 23-filter, 24-distribution plate, 25-1-external catalyst overflow pipe, 25-2-internal catalyst overflow pipe, 26-catalyst outlet, 27-catalyst inlet;

[0039] 3-drug outlet transfer tank: 31-catalyst inlet, 32-catalyst outlet, 33-air inlet, 34-air outlet, 35 heat exchange tube;

[0040] 4-esterification reactor: 41-air inlet, 42-air outlet, 43-filter, 44-distribution plate, 45-1-external catalyst overflow pipe, 45-2-internal catalyst overflow pipe, 46-catalyst outlet, 47-catalyst inlet;

[0041] 5-return agent transfer tank: 51-catalyst inlet, 52-catalyst outlet, 53-air inlet, 54-air outlet, 55 heat exchange tube; DETAILED DESCRIPTION

[0042] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but are not intended to limit the present invention.

[0043] It should be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the following description should not be considered as limiting, but merely as an example of an embodiment. Other modifications within the scope and spirit of the present disclosure will occur to those skilled in the art.

[0044] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the general description of the present disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.

[0045] These and other characteristics of the invention will become apparent from the following description of a preferred form of embodiment given as a non-limiting example, with reference to the accompanying drawings.

[0046] It should also be understood that although the present invention has been described with reference to some specific examples, those skilled in the art will be able to realize many other equivalent forms of the present invention that have the features described in the claims and are therefore within the scope of protection defined thereby.

[0047] The above and other aspects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

[0048] Specific embodiments of the present disclosure are described hereinafter with reference to the accompanying drawings; however, it should be understood that the disclosed embodiments are merely examples of the present disclosure, which may be implemented in a variety of ways. Well-known and / or repeated functions and structures are not described in detail to avoid obscuring the present disclosure with unnecessary or redundant details. Therefore, the specific structural and functional details disclosed herein are not intended to be limiting, but merely serve as a basis and representative basis for the claims to teach those skilled in the art to use the present disclosure in a variety of ways with substantially any suitable detailed structure.

[0049] This specification may use the phrases "in one embodiment," "in another embodiment," "in a further embodiment," or "in other embodiments," all of which may refer to one or more of the same or different embodiments according to the present disclosure.

[0050] In the first carboxylation reactor of the reaction device and method of the utility model, the solid or liquid furoic acid raw material is directly introduced into the reactor, rapidly gasified on the fluidized catalyst surface, then carboxylated and combined with the catalyst on the catalyst surface to form ortho-carboxylated acid salt compounds, and then the material is sent to the second esterification reactor to continue to react with methanol and CO 2 The reaction generates 2,5-furandicarboxylic acid ester, which enters the subsequent separation system in gaseous form. After separation, the product is acidified to obtain 2,5-furandicarboxylic acid (FDCA). The catalyst is separated from the product and reduced to its initial state, which is then recycled back to the first reactor to start a new reaction.

[0051] The method for continuously preparing dimethyl 2,5-furandicarboxylate using furoic acid as a raw material using the device according to the present application comprises the following steps:

[0052] 1) Weigh out the catalyst of each stage according to the specified weight, and then fill the catalyst into the corresponding reaction stage through the respective manholes or hand holes of the overflow pipes of the carboxylation reactor and the esterification reactor, and then seal the entire reaction device and check the air tightness.

[0053] 2) introducing carrier gas and CO into the reactor through the air inlet of the carboxylation reactor. 2 , the carrier gas and CO are introduced into the air inlet of the esterification reactor. 2 The system is replaced with methanol, and the system is started after the gas phase sampling of the entire reaction device is qualified.

[0054] 3) When the carboxylation reactor is normally fluidized and reaches a specified temperature, solid or liquid furoic acid raw material is added to the carboxylation reactor through the feeder of the feeding unit, and the control valve on the pipeline between the carboxylation reactor and the esterification reactor is opened synchronously, and the furoic acid in the carboxylation reactor reacts with CO in the presence of an alkaline catalyst. 2 A carboxylation reaction occurs to generate furandicarboxylate, which is attached to the catalyst surface in solid form. The catalyst then enters the catalyst outlet transfer tank through a pipeline, undergoes heat exchange and temperature and pressure regulation in the catalyst outlet transfer tank, and then enters the esterification reactor. In the esterification reactor, the furandicarboxylate attached to the catalyst surface reacts with CO 2 and methanol to form gaseous dimethyl furandicarboxylate, the product and unreacted CO 2 The methanol is removed from the reactor through the gas outlet at the top of the esterification reactor, and the catalyst with furandicarboxylate removed enters the return agent transfer tank through a pipeline, and is returned to the carboxylation reactor after pressure regulation and heat exchange in the return agent transfer tank, thus forming a catalyst cycle.

[0055] 4) The collected gas phase mixture containing dimethyl furandicarboxylate is cooled, and the product dimethyl furandicarboxylate is converted into a liquid phase and separated from the gas phase, and then subjected to conventional acidification treatment to obtain the final product furandicarboxylic acid 2,5-furandicarboxylic acid.

[0056] Preferably, during the reaction, the overflow pipes between different layers of the esterification reactor and the carboxylation reactor are opened to control the amount of catalyst between different fluidized layers in the two reactors to coordinate and complete the overall circulation of the catalyst.

[0057] Preferably, during the reaction, the heat exchange systems on the agent output transfer tank and the agent return transfer tank are turned on to heat the catalyst in the circulation process, and at the same time, the preheated carrier gas nitrogen is continuously introduced into the carboxylation reactor and the esterification reactor to fluidize and heat the catalysts in each section of the reactor. The carrier gas flows out through the gas outlet of the carboxylation reactor and the gas outlet of the esterification reactor, and continues to enter the subsequent carboxylation reactor filter and the esterification reactor filter to heat the filters together, and then flows out of the entire reaction device, and the heating process is carried out until the reaction system is heated to a specified temperature.

[0058] Preferably, the tail gas discharged from the gas outlet at the top of the carboxylation reactor is filtered and dust-removed, and then pressurized and returned to the carboxylation reactor to continue the reaction.

[0059] Preferably, the mixed gas discharged from the gas outlet at the top of the esterification reactor is filtered to remove dust, and then the tail gas after the product dimethyl 2,5-furandicarboxylate is separated out by cooling, and then is pressurized and returned to the esterification reactor to continue the reaction.

[0060] Preferably, the catalyst used in the carboxylation reactor and the esterification reactor in the preparation method of the utility model is a supported catalyst, mainly comprising a carrier and an active component, wherein the mass percentage of the active component is between 1% and 80% based on the total weight of the catalyst, the active component is selected from carbonates of alkali metals or alkaline earth metals, such as carbonates of potassium, sodium, magnesium, and cesium, and the carrier is selected from γ-Al 2 O 3 、SiO 2 、ZrO 2 、TiO 2 , HZSM5, SAPO-34, HY, Hβ and HMOR.

[0061] Preferably, the reaction temperature of the carboxylation reactor is 150°C-400°C, preferably 200-350°C, and the reaction pressure is 0.1-6MPa, preferably 1-6MPa. Within the above range, the reaction product conversion rate, product yield and production capacity are optimal.

[0062] Preferably, the mass space velocity of the furoic acid reaction in the carboxylation reactor is 0.1 to 1 h -1 , preferably 0.1 to 0.6h -1 Within this space velocity range, the reaction product conversion rate, product yield and production capacity are optimal.

[0063] Preferably, the furoic acid and CO in the carboxylation reactor 2 The molar ratio is 1:1 to 0.1:1, and the preferred ratio range is 0.5:1 to 0.2:1. Within the optimal ratio range, the raw material consumption and system energy consumption are optimal for the same output.

[0064] Preferably, the amount of methanol in the esterification reactor is 1 to 3 times the molar flow rate of furoic acid in the carboxylation reactor. 2 The dosage is added according to 0.2 to 1 times the molar flow rate of furoic acid. Within the optimal ratio range, the raw material consumption and system energy consumption are optimal for the same output.

[0065] Preferably, the reaction temperature in the esterification reactor is 200-400° C., and the reaction pressure is 1-10 MPa. The preferred reaction temperature is 200-300° C., and the reaction pressure is 4-8 MPa. Under these reaction conditions, the product conversion rate, product yield and production capacity are optimal.

[0066] Preferably, the temperature range of the discharge transfer tank is between 200 and 400° C., and the pressure is between 1 and 10 MPa.

[0067] Preferably, the temperature range of the return agent transfer tank is between 200 and 400° C., and the pressure is between 1 and 10 MPa.

[0068] Reference below Figure 1 The reaction device for continuously preparing 2,5-furandicarboxylic acid (FDCA) of the utility model is specifically described, and mainly comprises a feeding unit 1, a carboxylation reactor 2, an esterification reactor 4, a discharging agent transfer tank 3, a returning agent transfer tank 5 and the like:

[0069] The feeding unit 1 is located at one side of the carboxylation reactor 2 and is used for inputting reaction raw materials, and the raw materials can be solid raw materials or liquid raw materials.

[0070] Preferably, when the raw material is solid, the feeding unit 1 includes a silo 11 and a feeder 12 , and the solid raw material is stored in the silo 11 and transported to the carboxylation reactor 2 through the feeder 12 .

[0071] Preferably, the feeder 12 can be selected from conventional feeding equipment, for example, selected from, but not limited to, a screw feeder, or a star feeder.

[0072] Preferably, when the raw material is liquid, i.e., molten furoic acid (temperature is higher than 150° C.), the feeding unit 1 comprises a storage tank 11 and a feeding pump 12 , and the liquid raw material is stored in the storage tank 11 and transported to the carboxylation reactor 2 via the feeding pump 12 .

[0073] Furthermore, when the reaction raw materials are liquid, a liquid distributor 20-2 is also provided in the upper cylindrical structure of the carboxylation reactor 2, and the liquid distributor 20-2 includes but is not limited to a liquid distribution plate and an atomizing nozzle; the feed pump 12 of the feeding unit 1 is connected to the feed port 20-1 of the fluidized bed reactor through a pipeline, and the reaction raw materials are transported to the liquid distributor 20-2.

[0074] The carboxylation reactor 2 is a three-stage structure, with an upper cylindrical structure, a middle inverted cone structure, and a lower cylindrical structure. The diameter of the upper cylindrical structure is greater than the diameter of the lower cylindrical structure, and it is an expanded section. The upper and lower diameter ratio is 1.1:1 to 4:1, and they are connected to form a whole through the middle inverted cone structure. The angle between the cone surface of the middle inverted cone structure and the vertical direction is 15°-45°.

[0075] The carboxylation reactor 2 has at least one feed port 20, which is connected to the feed unit 1; a gas outlet 22 is provided at the top for conducting gaseous tail gas; and a gas inlet 21 is provided at the bottom for introducing CO into the reactor. 2 and a mixture of a carrier gas; the middle and lower part of the carboxylation reactor 2 is used as the main reaction zone, in which a single-stage or multi-stage horizontal distribution plate 24 is arranged for carrying the catalyst and distributing the gas, and at the same time dividing the reaction process into a number of corresponding reaction areas, and the catalysts loaded on the distribution plates at each stage can be the same or different; a funnel-shaped internal catalyst overflow pipe 25-2 is arranged in the main reaction zone, for making the catalyst in the carboxylation reactor 2 flow from the upper layer to the lower layer; a catalyst outlet 26 is arranged on the lower side of the carboxylation reactor 2, and a catalyst inlet 27 is arranged on the lower side of the carboxylation reactor 2.

[0076] Preferably, the gas outlet 22 of the carboxylation reactor 2 is connected to a filter 23, and the filter 23 is used to remove solid particles in the gas phase tail gas. The filter may include but is not limited to a screen with a corresponding aperture, a cyclone separator, etc.

[0077] refer to Figure 3 The discharging transfer tank 3 has a catalyst inlet 31 and a catalyst outlet 32, the catalyst inlet 31 is connected to the catalyst outlet 26 of the carboxylation reactor 2 through a pipeline, and the catalyst outlet 32 ​​of the discharging transfer tank 3 is connected to the esterification reactor 4 through a pipeline; the discharging transfer tank 3 is a shell and tube structure, and the temperature inside the discharging transfer tank 3 is adjusted by heat exchange of a heat exchange medium; the discharging transfer tank 3 has an air inlet 33 at the bottom and an exhaust gas outlet 34 at the top, which are used to adjust the pressure inside the discharging transfer tank; when the catalyst enters the discharging transfer tank 3 Before the reaction, close the slide valve on the catalyst inlet and outlet delivery pipeline connected to the discharge transfer tank 3, adjust its temperature and pressure to be consistent with the carboxylation reactor 2, then open the slide valve on the pipeline connecting the discharge transfer tank 3 and the carboxylation reactor 2, and the catalyst enters the discharge transfer tank 3, and then close the slide valve on the pipeline connecting the discharge transfer tank 3 and the carboxylation reactor 2; adjust the temperature and pressure in the discharge transfer tank 3 to be consistent with the esterification reactor 4, and then open the slide valve on the pipeline connecting the discharge transfer tank 3 and the esterification reactor 4 to transport the catalyst to the esterification reactor 4 for further reaction.

[0078] The general structure of the esterification reactor 4 is similar to that of the carboxylation reactor 2. A catalyst inlet 47 is provided in the middle of the esterification reactor 4, which is connected to the catalyst outlet 32 ​​of the catalyst outlet transfer tank 3 through a pipeline to receive the circulating catalyst; a gas outlet 42 is provided at the top for outputting the gas phase mixture containing dimethyl 2,5-furandicarboxylate; and a gas inlet 41 is provided at the bottom for introducing CO into the reactor. 2 , a mixture of methanol and a carrier gas; the lower and middle part of the esterification reactor 4 is used as the main reaction zone, in which a single-stage or multi-stage horizontal distribution plate 44 is arranged to carry the catalyst and distribute the gas, and at the same time divide the reaction process into a number of corresponding reaction areas, and the catalysts loaded on the distribution plates 44 at each stage can be the same or different; a funnel-shaped internal catalyst overflow pipe 45-2 is arranged in the main reaction zone to make the catalyst in the esterification reactor flow from top to bottom; a catalyst outlet 46 is arranged on the lower side of the esterification reactor 4.

[0079] Preferably, the gas outlet 42 of the esterification reactor 4 is connected to a filter 43, and the filter 43 is used to remove solid particles in the gas phase mixture. The filter may include but is not limited to a sieve with a corresponding aperture, a cyclone separator, etc.

[0080] refer to Figure 4 The return agent transfer tank 5 has a catalyst inlet 51 and a catalyst outlet 52. The catalyst inlet 51 of the return agent transfer tank 5 is connected to the catalyst outlet 46 of the esterification reactor 4 through a pipeline to receive the circulated catalyst. The catalyst outlet 52 of the return agent transfer tank 5 is connected to the catalyst inlet 27 of the carboxylation reactor 2 through a pipeline to return the circulated catalyst to the carboxylation reactor 2. The return agent transfer tank 5 is a shell and tube structure, and the temperature inside the return agent transfer tank is adjusted by heat exchange with a heat exchange medium, for example, heat exchange is performed through a heat exchange tube 55. The return agent transfer tank 5 has an air inlet 53 at the bottom and an exhaust gas outlet 54 at the top. Port 54 is used to adjust the pressure inside the return agent transfer tank 5; before the catalyst enters the return agent transfer tank 5, close the slide valve on the catalyst inlet and outlet delivery pipeline connected to the return agent transfer tank 5, adjust the internal temperature and pressure to be consistent with the esterification reactor 4, then open the slide valve on the pipeline connecting the return agent transfer tank 5 and the esterification reactor 4, the catalyst enters the return agent transfer tank 5, and then close the slide valve on the pipeline connecting the return agent transfer tank 5 and the esterification reactor 4; adjust the temperature and pressure in the return agent transfer tank 5 to be consistent with the carboxylation reactor 2, then open the slide valve on the pipeline connecting the return agent transfer tank 5 and the carboxylation reactor 2, and deliver the catalyst to the carboxylation reactor 2 to complete a reaction cycle.

[0081] Embodiment 1:

[0082] The fluidized bed size is selected as follows: reaction section Φ30mm, total length about 400mm, single-stage pressurized fluidized bed reactor, loading catalyst about 300g, esterification reactor 4 and carboxylation reactor 2 have the same size.

[0083] 1) After the system is replaced with nitrogen, CO is introduced into the reactor through the air inlet 21 of the carboxylation reactor 2. 2 , flow meter controls CO 2 The flow rate is about 20L / min, and the pressure of the reactor outlet 22 is adjusted to 1MPa to fluidize the catalyst in the carboxylation reactor 2;

[0084] 2) turning on auxiliary heating, and simultaneously continuously introducing preheated carrier gas nitrogen at a flow rate of about 20 L / min into the carboxylation reactor 2 to heat the reactor until the carboxylation reactor 2 is heated to about 150° C. and stably fluidized;

[0085] 3) Carboxylation reactor 2: the raw material is solid furoic acid, the feeding system 1 is turned on, and the speed of the feeder 12 is gradually adjusted to control the feeding rate of 100 g / h, and the reaction raw materials are fed into the carboxylation reactor 2;

[0086] 4) After furoic acid and the catalyst are mixed and fluidized in the fluidized bed carboxylation reactor 2, furoic acid is heated and gasified while reacting with CO in the presence of the catalyst. 2 The reaction produces 2,5-furandicarboxylate;

[0087] 5) adjusting the feed rate to zero and the temperature of the inlet gas to 280° C. respectively, thereby controlling the conversion rate of furoic acid and the amount of by-products generated to be less than 10%;

[0088] 6) Esterification reactor 4: switch the fluidizing gas to methanol, adjust the reaction temperature and pressure, continue the reaction to obtain dimethyl 2,5-furandicarboxylate, and the catalyst returns to the initial state. Methanol and the like flow out of the esterification reactor 4 from the top outlet 42 along with nitrogen, and after passing through the filtering unit 43 to remove a small amount of entrained catalyst fine powder, it flows out of the reaction device for cooling and collection.

[0089] The three catalysts were used to carry out the carboxylation esterification reaction of furoic acid. When the air velocity of the carboxylation reactor was 0.01h -1 When the reaction temperature is 280℃ and the pressure is 1MPa, the air velocity of the esterification reactor is 0.01h -1 When the reaction temperature is 200°C and the pressure is 8MPa, the results are as follows:

[0090] Catalyst 1 is TiO 2 Contains 9% K 2 CO 3 +1% Cs 2 CO 3: Furoic acid conversion rate 79.5%, 2,5-furandicarboxylic acid dimethyl ester selectivity 94%, by-product selectivity 6%, wherein catalyst 1 is a supported catalyst, TiO 2 As carrier, K 2 CO 3 and Cs 2 CO 3 is the active ingredient, K 2 CO 3 The above “9%” means that, based on the total weight of the catalyst, the active component K 2 CO 3 The weight percentage of the catalyst is 9%, and the other catalysts in the following examples are expressed in the same manner.

[0091] Catalyst 2 is TiO 2 Contains 10% K 2 CO 3 : Furoic acid conversion rate 69%, dimethyl 2,5-furandicarboxylate selectivity 93%, by-product selectivity 7%.

[0092] Catalyst 3 is TiO 2 Contains 10% Cs 2 CO 3 : Furoic acid conversion rate 89.8%, dimethyl 2,5-furandicarboxylate selectivity 91%, by-product selectivity 9%.

[0093] Embodiment 2:

[0094] The size of the selected esterification reactor is: reaction section Φ200mm, total length about 1200mm, single-stage pressurized fluidized bed reactor, and the catalyst loading is about 10kg.

[0095] The dimensions of the selected carboxylation reactor are: reaction section Φ300mm, total length about 1500mm, single-stage pressurized fluidized bed reactor, and catalyst loading of about 20kg.

[0096] 1) After the system is replaced with nitrogen, CO is introduced into the reactor through the air inlet 21 of the carboxylation reactor 2. 2 , flow meter controls CO 2 Flow rate: about 2m 3 / min, adjusting the pressure at the reactor outlet 22 to 1MPa, and fluidizing the catalyst in the carboxylation reactor 2;

[0097] 2) opening the slide valve on the pipeline between the carboxylation reactor 2 and the esterification reactor 4, so that the catalyst forms a circulation transport mode between the carboxylation reactor 2 and the esterification reactor 4, so that the amount of catalyst in each part during the catalyst circulation process is maintained stable;

[0098] 3) Turning on the heating systems on the agent transfer tank 3 and the counteragent transfer tank 5, heating the catalysts in the two transfer tanks, using the hot catalyst to replace the normal temperature catalysts of the two reactors, heating the carboxylation reactor 2 and the esterification reactor 4 to the specified reaction temperature, and stabilizing the fluidization;

[0099] 4) The raw material is solid furoic acid, the feeding system 1 is opened, and the speed of the feeder 12 is gradually adjusted to control the feeding rate to 3kg / h, and the reaction raw materials are sent into the carboxylation reactor 2;

[0100] 5) After furoic acid and the catalyst are mixed and fluidized in the carboxylation reactor 2, furoic acid is heated and gasified while reacting with CO in the presence of the catalyst. 2 The reaction generates 2,5-furandicarboxylic acid salts, which are solid and mixed with the catalyst;

[0101] 6) respectively adjusting the slide valves on the pipelines between the carboxylation reactor 2 and the esterification reactor 4 to control the material transfer rates of the carboxylation reactor 2 and the esterification reactor 3, controlling the output of 2,5-furandicarboxylic acid salts and entering the esterification reactor 4 with the catalyst mixture, and reacting with methanol in the esterification reactor 4 to generate dimethyl 2,5-furandicarboxylate and the initial catalyst;

[0102] 7) The obtained dimethyl 2,5-furandicarboxylate and unreacted methanol and other gases flow out from the gas outlet 42 at the top of the esterification reactor 4, pass through the filter 43 to remove a small amount of entrained catalyst fine powder, and then flow out of the reaction device for cooling and collection.

[0103] 8) The catalyst in the initial state in the esterification reactor 4 is returned to the carboxylation reactor 2 through the counter-agent transfer tank 5 for the next cycle.

[0104] The three catalysts were used to carry out the carboxylation esterification reaction of furoic acid. When the air velocity of the carboxylation reactor was 0.01h -1 When the reaction temperature is 280℃ and the pressure is 1MPa, the air velocity of the esterification reactor is 0.01h -1 When the reaction temperature is 200°C and the pressure is 8MPa, the results are as follows:

[0105] Catalyst 1 is TiO 2 Contains 9% K 2 CO 3 +1% Cs 2 CO 3 : Furoic acid conversion rate 86.5%, 2,5-furandicarboxylic acid dimethyl ester selectivity 94%, by-product selectivity 6%; catalyst 1 is a supported catalyst, TiO 2 As carrier, K 2 CO 3 and Cs 2 CO3 is the active ingredient, K 2 CO 3 The above “9%” means that, based on the total weight of the catalyst, the active component K 2 CO 3 The weight percentage of the catalyst is 9%, and the other catalysts in the following examples are expressed in the same manner.

[0106] Catalyst 2 is TiO 2 Contains 10% K 2 CO 3 : Furoic acid conversion rate 68%, dimethyl 2,5-furandicarboxylate selectivity 93%, by-product selectivity 7%;

[0107] Catalyst 3 is TiO 2 Contains 10% Cs 2 CO 3 : Furoic acid conversion rate 89.8%, dimethyl 2,5-furandicarboxylate selectivity 91%, by-product selectivity 9%;

[0108] Embodiment 3:

[0109] The fluidized bed size selected is: reaction section Φ200mm, total length about 1500mm, two-stage pressurized fluidized bed reactor, loading catalyst about 4kg in the upper section and 6kg in the lower section.

[0110] The dimensions of the selected carboxylation reactor are: reaction section Φ300mm, total length about 1500mm, two-stage pressurized fluidized bed reactor, loading catalyst about 8kg in the upper section and 12kg in the lower section.

[0111] 1) After the system is replaced with nitrogen, CO is introduced into the reactor through the air inlet 21 of the carboxylation reactor 2. 2 , flow meter controls CO 2 Flow rate: about 2m 3 / min, adjusting the pressure of the reactor outlet 22 to 1MPa, and fluidizing the catalyst in the carboxylation reactor 2;

[0112] 2) opening the external catalyst overflow pipe 25-1 and the internal catalyst overflow pipe 25-2 of different reaction sections on the carboxylation reactor 2 and the external catalyst overflow pipe 45-1 and the internal catalyst overflow pipe 45-2 of different reaction sections of the esterification reactor 4 to control the residence time of the materials in the reactors in different sections;

[0113] 3) opening the slide valve on the pipeline between the carboxylation reactor 2 and the esterification reactor 4, so that the catalyst forms a circulation transport mode between the carboxylation reactor 2 and the esterification reactor 4, so that the amount of catalyst in each part during the catalyst circulation process is maintained stable;

[0114] 4) Turning on the heating systems on the agent transfer tank 3 and the counteragent transfer tank 5, heating the catalysts in the two transfer tanks, using the hot catalyst to replace the normal temperature catalysts of the two reactors, heating the carboxylation reactor 2 and the esterification reactor 4 to the specified reaction temperature, and stabilizing the fluidization;

[0115] 5) The raw material is solid furoic acid, the feeding system 1 is opened, and the speed of the feeder 12 is gradually adjusted to control the feeding rate to 4kg / h, and the reaction raw materials are sent into the carboxylation reactor 2;

[0116] 6) After furoic acid and the catalyst are mixed and fluidized in the carboxylation reactor 2, furoic acid is heated and gasified while reacting with CO in the presence of the catalyst. 2 The reaction generates 2,5-furandicarboxylic acid salts, which are solid and mixed with the catalyst;

[0117] 7) respectively adjusting the opening of the slide valve on the pipeline between the carboxylation reactor 2 and the esterification reactor 4, controlling the material transfer rate of the carboxylation reactor 2 and the esterification reactor 4, controlling the output of 2,5-furandicarboxylic acid salts and entering the esterification reactor 4 with the catalyst mixture, and reacting with methanol in the esterification reactor 4 to generate dimethyl 2,5-furandicarboxylate and the initial catalyst;

[0118] 8) The obtained dimethyl 2,5-furandicarboxylate and unreacted methanol and other gases flow out from the gas outlet 42 at the top of the esterification reactor 4, pass through the filter 43 of the esterification reactor 4 to remove a small amount of entrained catalyst fine powder, and then flow out of the reaction device for cooling and collection.

[0119] The catalyst in the initial state in the esterification reactor 4 is returned to the carboxylation reactor 2 through the counter-agent transfer tank 5 for the next cycle.

[0120] The three catalysts were used to carry out the carboxylation esterification reaction of furoic acid. When the air velocity of the carboxylation reactor was 0.01h -1 When the reaction temperature is 280℃ and the pressure is 1MPa, the air velocity of the esterification reactor is 0.01h -1 When the reaction temperature is 200°C and the pressure is 8MPa, the results are as follows:

[0121] Catalyst 1 is TiO 2 Contains 9% K 2 CO 3 +1% Cs 2 CO 3 : Furoic acid conversion rate 91.5%, 2,5-furandicarboxylic acid dimethyl ester selectivity 94%, by-product selectivity 6%; wherein catalyst 1 is a supported catalyst, TiO 2 As carrier, K 2 CO 3 and Cs 2 CO3 is the active ingredient, K 2 CO 3 The above “9%” means that, based on the total weight of the catalyst, the active component K 2 CO 3 The weight percentage of the catalyst is 9%, and the other catalysts in the following examples are expressed in the same manner.

[0122] Catalyst 2 is TiO 2 Contains 10% K 2 CO 3 : Furoic acid conversion rate 65%, dimethyl 2,5-furandicarboxylate selectivity 93%, by-product selectivity 7%;

[0123] Catalyst 3 is TiO 2 Contains 9% K 2 CO 3 +1% Cs 2 CO 3 : Furoic acid conversion rate 89.8%, dimethyl 2,5-furandicarboxylate selectivity 91%, by-product selectivity 9%;

[0124] The above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model is described in detail with reference to the above embodiments, ordinary technicians in this field should understand that the technical solutions recorded in the above embodiments can be modified, or part or all of the technical features can be replaced by equivalents without departing from the spirit and essence of the claims of the utility model; and these modifications or replacements are still within the scope defined by the claims of the utility model.

Claims

1. A device for continuously preparing 2,5-furandicarboxylic acid, characterized in that: It includes a feed unit, a carboxylation reactor, an esterification reactor, a discharging agent transfer tank, and a returning agent transfer tank; Wherein, the feeding unit is located on one side of the carboxylation reactor and is used for inputting reaction raw materials, and the raw materials are solid raw materials or liquid raw materials; The carboxylation reactor is a three-stage structure, the upper part is a cylindrical structure, the middle part is an inverted cone structure, and the lower part is a cylindrical structure. The diameter of the upper cylindrical structure is greater than the diameter of the lower cylindrical structure, which is an expanded section; the upper and lower diameter ratio is 1.1:1 to 4:1, and the middle inverted cone structure is connected to form a whole, and the cone surface of the middle inverted cone structure has an angle of 15° to 45° with the vertical direction; The carboxylation reactor has at least one feed port, which is connected to the feed unit; a gas outlet is provided at the top for conducting gaseous tail gas; a gas inlet is provided at the bottom for introducing a mixed gas of CO2 and a carrier gas into the reactor; the middle and lower part of the carboxylation reactor is used as a main reaction zone, wherein a single-stage or multi-stage horizontal distribution plate is provided for carrying a catalyst and distributing gas, and the reaction process is divided into a number of corresponding reaction areas; a funnel-shaped internal catalyst overflow pipe is provided in the main reaction zone for causing the catalyst in the carboxylation reactor to flow from the upper layer to the lower layer; a catalyst outlet is provided on the lower side of the carboxylation reactor, and a catalyst inlet is provided on the lower side of the carboxylation reactor; The discharge transfer tank has a catalyst inlet and a catalyst outlet, the catalyst inlet is connected to the catalyst outlet of the carboxylation reactor through a pipeline, and the catalyst outlet of the discharge transfer tank is connected to the esterification reactor through a pipeline; the discharge transfer tank is a shell and tube structure, and the temperature inside the discharge transfer tank is adjusted by heat exchange with a heat exchange medium; the discharge transfer tank has an air inlet at the bottom and an exhaust gas outlet at the top, which are used to adjust the pressure inside the discharge transfer tank; The middle part of the esterification reactor is provided with a catalyst inlet, which is connected to the catalyst outlet of the agent transfer tank through a pipeline to receive the circulating catalyst; the top is provided with a gas outlet for discharging a gas phase mixture containing dimethyl 2,5-furandicarboxylate; the bottom is provided with a gas inlet for introducing a mixed gas of CO2, methanol and carrier gas into the reactor; the middle and lower part of the esterification reactor is used as the main reaction zone, in which a single-stage or multi-stage horizontal distribution plate is provided for carrying the catalyst and distributing the gas, and at the same time dividing the reaction process into several corresponding reaction areas; a funnel-shaped internal catalyst overflow pipe is provided in the main reaction zone to make the catalyst in the esterification reactor flow from top to bottom; a catalyst outlet is provided on the side of the lower part of the esterification reactor; The return agent transfer tank has a catalyst inlet and a catalyst outlet. The catalyst inlet of the return agent transfer tank is connected to the catalyst outlet of the esterification reactor through a pipeline to receive the circulating catalyst. The catalyst outlet of the return agent transfer tank is connected to the catalyst inlet of the carboxylation reactor through a pipeline to return the circulated catalyst to the carboxylation reactor.

2. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that: The feeding unit comprises a silo and a feeder.

3. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 2, characterized in that: The feeder comprises a screw feeder or a star feeder, and the feeder is directly connected to the feed port of the carboxylation reactor.

4. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that: When the reaction raw materials are in liquid phase, the feeding unit includes a storage tank and a feeding pump.

5. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that: When the reaction raw materials are in liquid phase, a liquid distributor is also arranged in the upper cylindrical structure of the carboxylation reactor, and the liquid distributor includes a liquid distribution plate and an atomizing nozzle; the feed pump of the feed unit is connected to the feed port of the carboxylation reactor through a pipeline, and the reaction raw materials are transported to the liquid distributor.

6. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that: The gas outlet of the carboxylation reactor is connected to a filter, and the filter is used to remove solid particles in the gas phase tail gas; The gas outlet of the esterification reactor is connected to a filter, and the filter is used to remove solid particles in the gas phase mixture; The filter comprises a screen with corresponding apertures and a cyclone separator.

7. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that: The pipelines connecting the catalyst inlet and the catalyst outlet of the catalyst transfer tank are both provided with slide valves for controlling the catalyst flow or the on-off of the pipeline.

8. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that: The pipelines connecting the catalyst inlet and the catalyst outlet of the return agent transfer tank are both provided with slide valves for controlling the catalyst flow or the on-off of the pipeline.

9. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that: An external catalyst overflow pipe is arranged on the outer wall of the carboxylation reactor at a position corresponding to the position of the funnel-shaped internal catalyst overflow pipe in the carboxylation reactor, and is also used to make the catalyst in the carboxylation reactor flow from top to bottom.

10. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that: An external catalyst overflow pipe is arranged at a position on the outer wall of the esterification reactor corresponding to the position of the funnel-shaped internal catalyst overflow pipe in the esterification reactor, and is also used to make the catalyst in the esterification reactor flow from top to bottom.

11. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that: The carboxylation reactor and the esterification reactor are fluidized bed reactors.

12. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that: The distribution plates arranged in the carboxylation reactor and the esterification reactor include porous plates, sieve plates and bubble cap plates.

13. The device for continuously preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that: The return agent transfer tank is a shell and tube structure, and the temperature inside the return agent transfer tank is adjusted by heat exchange with a heat exchange medium; the return agent transfer tank has an air inlet at the bottom and an exhaust gas outlet at the top, which are used to adjust the pressure inside the return agent transfer tank; before the catalyst enters the return agent transfer tank, the slide valve on the catalyst inlet and outlet pipeline connected to the return agent transfer tank is closed, and the internal temperature and pressure are adjusted to be consistent with the esterification reactor, and then the slide valve on the connecting pipeline between the return agent transfer tank and the esterification reactor is opened, the catalyst enters the return agent transfer tank, and then the slide valve on the connecting pipeline between the return agent transfer tank and the esterification reactor is closed; the temperature and pressure inside the return agent transfer tank are adjusted to be consistent with the carboxylation reactor, and then the slide valve on the connecting pipeline between the return agent transfer tank and the carboxylation reactor is opened to transport the catalyst to the carboxylation reactor to complete a reaction cycle.

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