Device for continuously preparing dimethyl furan-2, 5-dicarboxylate by taking furoic acid or methyl furoate as raw material

Abstract

The utility model discloses a device for continuously preparing dimethyl 2, 5-furandicarboxylate by taking furoic acid or methyl furoate as a raw material, which is characterized in that the reaction device adopts the design of a core fluidized esterification bed reactor, so that the process of synthesizing the dimethyl 2, 5-furandicarboxylate is changed into gas-solid fluidized bed reaction from a kettle type reaction process, and the yield of the dimethyl 2, 5-furandicarboxylate is increased. Raw materials such as furoic acid / methyl furoate are directly introduced into a reactor without heating, rapidly gasified on the surface of a fluidized catalyst and combined with a methanol catalyst on the surface of the catalyst to generate dimethyl furan-2, 5-dicarboxylate, the dimethyl furan-2, 5-dicarboxylate enters a subsequent separation system in a gaseous form under reaction conditions, and the separated product is purified to obtain the dimethyl furan-2, 5-dicarboxylate. The reaction speed is greatly accelerated through the new process, the characteristic that the product and the catalyst are difficult to separate after salifying is avoided through the esterification reaction, and the system efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical synthesis, and specifically relates to a device for preparing dimethyl 2,5-furandicarboxylate by taking furoic acid or methyl furoate as raw materials. Background Art

[0002] 2,5-Furandicarboxylic acid, chemical formula is C6H4O5, 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 process will stay in the intermediate step, resulting in incomplete reaction, and the intermediate product is difficult to separate from 2,5-furandicarboxylic acid. It is not yet 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 furanic acid as raw material. Patent CN106925262 A discloses a catalyst for photocatalytic preparation of 2,5-furandicarboxylic acid, including a carrier and an active metal component. The mass fraction of the active metal component is 1%-20% by weight of the final catalyst, and the rest is a carrier. The carrier is one of graphene, silicon carbide, aluminum oxide, silicon dioxide, activated carbon or carbon nitride. The active metal component is one or two of gold, palladium, platinum, silver, ruthenium and rhodium. Chinese patent (CN103626726A) discloses a method for preparing 2,5-furandicarboxylic acid by selective oxidation of 5-hydroxymethylfurfural catalyzed by an acidic carrier loaded with precious metal in an aqueous solution. The method has mild reaction conditions, high reaction efficiency and good selectivity, but a large amount of alkaline solution needs to be added to the reaction. 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. In patent CN 114450273 A, an aqueous solution of potassium hydroxide and potassium acetate is added to furoic acid. Water is removed to produce a white solid, and the powder is reacted with CO2 in an autoclave for 2 hours to obtain a yield of 90% for FDCA, 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, an object of the utility model is to provide a device for continuously preparing dimethyl 2,5-furandicarboxylate, wherein the method of the device is used to generate dimethyl 2,5-furandicarboxylate with cheap and readily available furoic acid or methyl furoate and methanol in the presence of a catalyst. The product dimethyl 2,5-furandicarboxylate is in a gas phase under the reaction conditions and can be separated from the solid catalyst, and the obtained dimethyl 2,5-furandicarboxylate can be further acidified to generate 2,5-furandicarboxylic acid.

[0008] Technical Solution

[0009] According to one aspect of the utility model, there is provided a device for continuously preparing dimethyl 2,5-furandicarboxylate, comprising a feeding unit, a fluidized bed esterification reactor, and a catalyst regeneration unit;

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

[0011] The fluidized bed esterification 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, and it is an expanded section. The upper and lower diameter ratio is 1.1:1-4:1, 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°.

[0012] The fluidized bed esterification 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 mixture; a gas inlet is provided at the bottom for introducing a mixture of methanol and carrier gas into the reactor; the middle and lower part of the reactor is used as the main reaction zone, wherein a single-stage or multi-stage horizontal distribution plate is provided for carrying the catalyst and distributing the gas, and the reaction process is divided 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 is provided in the main reaction zone for making the catalyst in the reactor flow from top to bottom; a discharge port is provided on the side of the lower part of the reactor, and a return port is provided on the side of the middle and upper part of the reactor;

[0013] The catalyst regeneration unit includes a catalyst inlet arranged on the upper side, which is connected to the agent outlet of the fluidized bed esterification reactor through a pipeline, an air inlet is arranged at the bottom of the catalyst regeneration unit and an air outlet is arranged at the top, wherein the air inlet is used to introduce oxygen-containing gas, and the tail gas after regeneration treatment is discharged from the air outlet, and a catalyst outlet is arranged on the lower side of the catalyst regeneration unit, which is connected to the agent return port of the fluidized bed esterification reactor through a pipeline, and the regenerated catalyst is returned to the fluidized bed esterification reactor by the carrier gas to start a new reaction.

[0014] Preferably, when the reaction raw materials are in a solid phase, the feeding unit comprises a silo and a feeder.

[0015] Furthermore, when the reaction raw materials are in solid phase, 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 fluidized bed esterification reactor.

[0016] Preferably, when the reaction raw materials are in liquid phase, the feeder comprises a storage tank and a feed pump.

[0017] Furthermore, when the reaction raw materials are in liquid phase, a liquid distributor is also arranged in the upper cylindrical structure of the fluidized bed esterification reactor, and the liquid distributor includes but is not limited to a liquid distribution plate and an atomizing nozzle; the feed pump of the feeding unit is connected to the feed port of the fluidized bed esterification reactor through a pipeline, and the reaction raw materials are transported to the liquid distributor.

[0018] Preferably, the gas outlet of the fluidized bed esterification reactor is connected to a filter, and the filter is used to remove solid particles in the gas phase mixture.

[0019] Preferably, the filter may include but is not limited to a screen with corresponding aperture, a cyclone separator, etc.

[0020] Preferably, an external catalyst overflow pipe is arranged at a position on the outer wall of the reactor corresponding to the position of the internal catalyst overflow pipe, which is also used to make the catalyst in the reactor flow from top to bottom, coordinating the catalyst transportation between the esterification reactor and the regenerator to form a complete catalyst circulation process.

[0021] Preferably, a gas distributor is provided inside the lower part of the catalyst regeneration unit, which is connected to the gas inlet and is used to maintain uniform distribution of gas flow inside the catalyst regeneration unit.

[0022] Preferably, a slide valve is installed on the connecting pipeline between the catalyst inlet of the catalyst regeneration unit and the catalyst outlet of the fluidized bed esterification reactor for adjusting and controlling the catalyst flow between the fluidized bed esterification reactor and the catalyst regeneration unit.

[0023] Preferably, a slide valve is installed on the connecting pipeline between the catalyst outlet of the catalyst regeneration unit and the return port of the fluidized bed esterification reactor for adjusting and controlling the catalyst flow between the fluidized bed esterification reactor and the catalyst regeneration unit.

[0024] Preferably, the distribution plate provided in the fluidized bed esterification reactor includes but is not limited to a porous plate, a sieve plate, a bubble cap plate and the like.

[0025] Preferably, the gas distributor in the catalyst regeneration unit includes but is not limited to a porous tube, a porous plate, a sieve plate, and a bubble cap plate.

[0026] Preferably, an exchange / heating system is disposed outside the catalyst regeneration unit and around the catalyst regeneration unit, for exchanging heat or heating the catalyst regeneration unit.

[0027] Preferably, when the catalyst in the fluidized bed esterification reactor needs to be regenerated, the air inlet at the bottom and the air outlet at the top of the regeneration unit are first opened, and then the agent outlet of the esterification reactor and the catalyst inlet of the regeneration unit are connected, so that the catalyst to be regenerated enters the regeneration unit with the carrier gas, and the catalyst reacts with the oxygen-containing gas in the regeneration unit to remove the carbon material deposited on the surface of the catalyst to complete the catalyst regeneration, and the tail gas is discharged from the top air outlet of the regeneration unit, and the regenerated catalyst is sent to the agent return port of the esterification reactor through the catalyst outlet of the regeneration unit to start a new reaction.

[0028] Beneficial Effects

[0029] According to the reaction device and method of the utility model, the reaction process of furoic acid / methyl furoate to generate 2,5-furandicarboxylic acid dimethyl ester compound is targeted. Through the core fluidized esterification bed reactor design, the process of furoic acid synthesizing 2,5-furandicarboxylic acid dimethyl ester is changed from the traditional kettle reaction process to a gas-solid fluidized bed reaction. The raw materials such as furoic acid / methyl furoate are directly introduced into the reactor without heating, and are rapidly gasified on the fluidized catalyst surface. On the catalyst surface, they are combined with the methanol catalyst to generate 2,5-furandicarboxylic acid dimethyl ester. The 2,5-furandicarboxylic acid ester generated by the reaction enters the subsequent separation system in a gaseous form under the reaction conditions. After separation, the product is purified to obtain 2,5-furandicarboxylic acid dimethyl ester. The catalyst is separated from the product and restored to the initial state, and a new reaction is started. The reaction speed is greatly accelerated by the new process, and the difficulty of separating the product and the catalyst after salt formation is avoided by the esterification reaction, thereby improving the system efficiency. After the catalyst further participates in the reaction, the separation cycle is completed directly in the reaction system, reducing the separation unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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.

[0031] Figure 1 This is a schematic structural diagram of an apparatus for the method for continuously preparing 2,5-furandicarboxylic acid according to the utility model, wherein the raw material is a solid phase, and the feeding unit includes a silo and a feeder.

[0032] Figure 2This is a schematic structural diagram of the device for the method for continuously preparing 2,5-furandicarboxylic acid according to the utility model, wherein the raw material is in liquid phase, the feeder includes a storage tank and a feed pump, and a liquid distributor is also arranged in the upper cylindrical structure of the fluidized bed esterification reactor.

[0033] Figure 3 The present invention is a schematic structural diagram of the catalyst regeneration unit in the device for the method for continuously preparing 2,5-furandicarboxylic acid according to the present invention.

[0034] Reference numerals:

[0035] 1-Feeding unit: 11-silo / storage tank, 12-feeder / feeding pump;

[0036] 2- fluidized bed esterification reactor: 20 / 20-1 feed port, 20-2 liquid distributor, 21- air inlet, 22- air outlet, 23- filter, 24- distribution plate, 25-1- external catalyst overflow pipe, 25-2- internal catalyst overflow pipe, 26- agent outlet, 27- agent return port;

[0037] 3-Catalyst regeneration unit: 30-gas distributor, 31-catalyst inlet, 32-catalyst outlet, 33-gas inlet, 34-gas outlet. DETAILED DESCRIPTION

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] The method using the device according to the utility model comprises the following steps:

[0047] 1) Weigh out the catalyst of each section according to the specified weight, and then load the catalyst onto the corresponding distribution plate through the manhole or hand hole of each section of the esterification reactor, and then seal the entire reaction device and check the air tightness;

[0048] 2) introducing methanol and carrier gas into the fluidized bed esterification reactor through the air inlet to replace the system, and starting the system after the gas phase sampling of the entire reaction device is qualified and the fluidized bed esterification reactor reaches the reaction temperature;

[0049] 3) feeding the fluidized bed esterification reactor through a feeding unit, wherein furoic acid is a solid feed and methyl furoate is a liquid feed,

[0050] 4) connecting the catalyst regeneration unit with the fluidized bed esterification reactor, circulating the heated catalyst into the esterification reactor, so that the heated catalyst in the catalyst regeneration unit is gradually mixed with the catalyst in the reactor to increase the temperature and circulate until each section of the esterification reactor reaches the specified temperature;

[0051] 5) After normal fluidization and reaching the specified temperature, the raw material furoic acid / furoic acid methyl ester is gradually introduced into the reactor through the feeding unit, and the fluidization reaction is stabilized under the reaction conditions to generate gaseous 2,5-furandicarboxylic acid dimethyl ester, the 2,5-furandicarboxylic acid dimethyl ester, the unreacted methanol and the carrier gas are discharged from the fluidized bed esterification reactor from the gas outlet, and the gas-solid separation treatment is performed through the filter, and then the product mixed gas is cooled, the product 2,5-furandicarboxylic acid dimethyl ester is liquefied and separated from the unreacted methanol, and the 2,5-furandicarboxylic acid dimethyl ester is further acidified to obtain 2,5-furandicarboxylic acid, and the methanol in the tail gas is purified and then pressurized and sent to the fluidized bed esterification reactor to continue the reaction.

[0052] Preferably, the catalyst in the preparation method according to 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 60% 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 one or more of γ-Al2O3, SiO2, ZrO2, TiO2, HZSM5, SAPO-34, HY, Hβ and HMOR.

[0053] Preferably, the mass space velocity of the reactant furoic acid / methyl furoate is controlled to be 0.1 to 1 h -1 , preferably 0.2~0.6h -1 The molar ratio of methanol to raw material is between 1:1 and 3:1, preferably between 1.2:1 and 2:1. Under the preferred conditions, the conversion rate of reactants, the yield of products and the production capacity are optimal.

[0054] Preferably, the carrier gas includes but is not limited to one or more of nitrogen, helium and argon.

[0055] More preferably, during the reaction in the fluidized bed esterification reactor, CO2 may be appropriately added, and the molar ratio of the added CO2 to methanol is 0.1:1 to 1:1, preferably 0.2:1 to 0.5:1, which alleviates the occurrence of side reactions within the preferred range while reducing raw material consumption and system energy consumption.

[0056] Preferably, the reaction temperature of the fluidized bed esterification reactor is 150°C-400°C, preferably 200°C-350°C, and the reaction pressure is 0.1-6MPa, preferably 1-4MPa. Under the preferred conditions, the reactant conversion rate, product yield and production capacity are optimal.

[0057] Preferably, the reaction temperature of the catalyst regeneration unit is between 300 and 800°C, preferably 400°C-600°C, and the pressure is 0.1-6MPa, preferably 1-4MPa. Under the preferred conditions, the catalyst regeneration effect and the comprehensive energy consumption are optimal.

[0058] Preferably, the reaction temperature in the catalyst regeneration unit is controlled between 350 and 600° C., and the regeneration time is controlled between 10 and 100 minutes.

[0059] Preferably, the gas inlet of the catalyst regeneration unit is introduced with an oxygen-containing gas, and the oxygen-containing gas is selected from air, oxygen-rich gas, and oxygen.

[0060] Reference below Figure 1 and Figure 2 The device for continuously preparing dimethyl 2,5-furandicarboxylate of the utility model is specifically described, and mainly comprises a feeding unit 1, a fluidized bed esterification reactor 2, and a catalyst regeneration unit 3. The feeding unit 1 mainly comprises: a silo 11, a feeder 12 (or a storage tank 11, a feed pump 12), etc.; the feeder 12 or the feed pump 12 of the feeding unit 1 is connected to the fluidized bed esterification reactor 2 through a feed port 20 for inputting reaction raw materials.

[0061] The fluidized bed esterification 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 that of the lower cylindrical structure, and is an expanded section. The upper and lower diameter ratios are 1.1:1 to 4:1, and are connected to form a whole through a middle inverted cone structure. The angle between the cone surface of the middle inverted cone structure and the vertical direction is 15°-45°.

[0062] The fluidized bed esterification reactor 2 has at least one feed port 20, and the feed port 20 is connected to the feed unit 1; the top of the fluidized bed esterification reactor is provided with a gas outlet 22 for conducting the gas phase mixture; the bottom is provided with a gas inlet 21 for introducing the mixed gas of methanol and carrier gas into the reactor 2; the middle and lower part of the reactor 2 is used as the main reaction zone, wherein a single-stage or multi-stage horizontal distribution plate 24 is provided, which is used to carry the catalyst and distribute the gas, and at the same time divides the reaction process into a number of corresponding reaction areas, and the catalysts loaded on the distribution plates 24 at each stage can be the same or different; a funnel-shaped internal catalyst overflow pipe 25-2 is provided in the main reaction zone, which is used to make the catalyst in the reactor 2 flow from top to bottom; a discharge port 26 is provided at the lower part of the reactor 2, and a return port 27 is provided at the middle and lower part of the reactor 2;

[0063] The catalyst regeneration unit 3 includes a catalyst inlet 31 arranged on the upper side, which is connected to the outlet 26 of the fluidized bed esterification reactor 2 through a pipeline. The catalyst regeneration unit 3 is provided with an air inlet 33 at the bottom and an air outlet 34 at the top, wherein the air inlet 33 is used to introduce oxygen-containing gas, and the tail gas after regeneration treatment is discharged from the air outlet. The catalyst regeneration unit is provided with a catalyst outlet on the lower side, which is connected to the return port 27 of the fluidized bed esterification reactor 2 through a pipeline. The regenerated catalyst is returned to the fluidized bed esterification reactor 2 by the carrier gas to start a new reaction. The catalyst circulation between the fluidized bed esterification reactor 2 and the regenerator 3, combined with the catalyst flowing from top to bottom through the overflow pipe 25 in the fluidized bed esterification reactor 2, completes the closed circulation of the catalyst.

[0064] Preferably, when the reaction raw material furoic acid is in a solid phase, the feeding unit 1 includes a silo 11 and a feeder 12 .

[0065] If the reaction raw materials are in solid phase, the feeder 12 includes but is not limited to a screw feeder or a star feeder, and the feeder is directly connected to the feed port 20 of the fluidized bed esterification reactor 2 .

[0066] Preferably, when the reaction raw material methyl furoate is in liquid phase, the feeder 12 includes a storage tank 11 and a feed pump 12 .

[0067] Furthermore, when the reaction raw materials are in liquid phase, a liquid distributor 20-2 is also provided in the upper cylindrical structure of the fluidized bed esterification 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 esterification reactor 2 through a pipeline, and the reaction raw materials are transported to the liquid distributor 20-2.

[0068] Preferably, the gas outlet 22 of the fluidized bed esterification reactor 2 is connected to a filter 23, and the filter 23 is used to remove solid particles in the gas phase mixture.

[0069] Preferably, the filter 23 may include but is not limited to a screen with corresponding aperture, a cyclone separator, etc.

[0070] Preferably, an external catalyst overflow pipe 25 - 1 is provided on the outer wall of the reactor 2 at a position corresponding to the position of the internal catalyst overflow pipe 25 - 2 , and is also used to make the catalyst in the reactor 2 flow from top to bottom.

[0071] Preferably, a gas distributor 30 is provided inside the lower part of the catalyst regeneration unit 3, which is connected to the gas inlet 33 and is used to maintain uniform distribution of gas flow inside the catalyst regeneration unit.

[0072] Preferably, a sliding valve (not shown in the figure) is installed on the connecting pipeline between the catalyst inlet 31 of the catalyst regeneration unit 3 and the outlet 26 of the fluidized bed esterification reactor for adjusting and controlling the catalyst flow between the fluidized bed esterification reactor and the catalyst regeneration unit 3.

[0073] Preferably, a sliding valve (not shown in the figure) is installed on the connecting pipeline between the catalyst outlet 32 ​​of the catalyst regeneration unit 3 and the return port 27 of the fluidized bed esterification reactor 2 for adjusting and controlling the catalyst flow between the fluidized bed esterification reactor 2 and the catalyst regeneration unit 3.

[0074] Preferably, the distribution plate 24 provided in the fluidized bed esterification reactor 2 includes but is not limited to a porous plate, a sieve plate, a bubble cap plate and the like.

[0075] Preferably, the gas distributor 30 in the catalyst regeneration unit 3 includes but is not limited to a porous tube, a porous plate, a sieve plate, and a bubble cap plate.

[0076] Preferably, an exchange / heating system is disposed outside the catalyst regeneration unit 3 and around the catalyst regeneration unit 3, for exchanging heat or heating the catalyst regeneration unit.

[0077] Reference below Figure 1 and Figure 2 The specific operation mode of the method of the utility model is specifically described as follows:

[0078] 1) Weigh out the catalyst of each section according to the specified weight, and then load the catalyst onto the corresponding distribution plate 24 through the manhole or hand hole (not shown in the figure) of each section of the fluidized bed esterification reactor 2, and then seal the entire reaction device and check the air tightness;

[0079] 2) introducing methanol and carrier gas into the fluidized bed esterification reactor 2 through the gas inlet 21 of the reactor 2 to replace the system, and starting the system after the gas phase sampling of the entire reaction device is qualified and the fluidized bed esterification reactor 2 reaches the reaction temperature;

[0080] 3) feeding the fluidized bed esterification reactor 2 described in 1 through a feeding unit, wherein furoic acid is a solid feed and methyl furoate is a liquid feed,

[0081] 4) connecting the catalyst regeneration unit 3 with the fluidized bed esterification reactor 2, circulating the heated catalyst into the esterification reactor 2, so that the catalyst regenerated in the catalyst regeneration unit 3 is gradually mixed with the catalyst in the reactor 2 to increase the temperature and circulate until each section of the fluidized bed esterification reactor 2 reaches the specified temperature;

[0082] 5) After normal fluidization and reaching the specified temperature, the raw material furoic acid / methyl furoate is gradually introduced into the fluidized bed esterification reactor 2 through the feeding unit 1, and the fluidized reaction is stabilized under the reaction conditions to generate gaseous 2,5-furandicarboxylic acid dimethyl ester. The 2,5-furandicarboxylic acid dimethyl ester, unreacted methanol and carrier gas are discharged from the fluidized bed esterification reactor 2 from the gas outlet 22, and are subjected to gas-solid separation treatment through the filter 23. Then, the product mixed gas is cooled, and the product 2,5-furandicarboxylic acid dimethyl ester is liquefied and separated from the unreacted methanol. The 2,5-furandicarboxylic acid dimethyl ester is further acidified to obtain 2,5-furandicarboxylic acid. The methanol in the tail gas is purified and then pressurized and fed into the fluidized bed esterification reactor 2 to continue the reaction.

[0083] Preferably, the catalyst in the preparation method according to 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 60% 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 one or more of γ-Al2O3, SiO2, ZrO2, TiO2, HZSM5, SAPO-34, HY, Hβ and HMOR.

[0084] The catalyst can be prepared by a conventional impregnation method in the art.

[0085] Preferably, the mass space velocity of the reactant furoic acid / methyl furoate is controlled to be 0.1 to 1 h -1 , preferably at a mass space velocity of 0.1 to 0.6 h -1 The molar ratio of methanol to raw material is between 1:1 and 3:1, preferably between 1.2:1 and 2:1, within this preferred range.

[0086] More preferably, during the reaction in the fluidized bed esterification reactor 3, CO2 may be appropriately added, and the molar ratio of the added CO2 to methanol is 0.1:1 to 1:1, so as to alleviate the occurrence of side reactions.

[0087] Preferably, the reaction temperature of the fluidized bed esterification reactor 2 is 150°C-400°C, preferably 200°C-350°C, and the reaction pressure is 0.1-6MPa, preferably 1-6MPa. Under the preferred conditions, the reaction product conversion rate, product yield and production capacity are optimal.

[0088] Preferably, the reaction temperature of the catalyst regeneration unit 3 is between 300 and 800°C, preferably 400°C-650°C, and the pressure is 0.1-6MPa, preferably 1-6MPa. Under the preferred conditions, the catalyst regeneration effect and energy consumption are optimal.

[0089] Preferably, the reaction temperature in the catalyst regeneration unit 3 is controlled between 350 and 600° C., and the regeneration time is controlled between 0.1 and 2 hours.

[0090] Preferably, the air inlet 33 of the catalyst regeneration unit 3 is introduced with an oxygen-containing gas, and the oxygen-containing gas is selected from air, oxygen-rich gas, and oxygen.

[0091] Preferably, when the catalyst in the fluidized bed esterification reactor 2 needs to be regenerated, the air inlet 33 at the bottom and the air outlet 34 at the top of the regeneration unit 3 are first opened, and then the agent outlet 26 of the esterification reactor 2 is connected to the catalyst inlet 31 of the regeneration unit 3, so that the catalyst to be regenerated enters the regeneration unit 3 with the carrier gas, and the catalyst reacts with the oxygen-containing gas in the regeneration unit 3 to remove the carbon material deposited on the catalyst surface to complete the catalyst regeneration, and the tail gas is discharged from the top air outlet 34 of the regeneration unit 3, and the regenerated catalyst is sent to the return agent port 27 of the esterification reactor 3 through the catalyst outlet 32 ​​of the regeneration unit 3 to start a new reaction.

[0092] Embodiment 1:

[0093] The fluidized bed size selected is: reaction section Φ30mm, total length about 400mm, single-stage pressurized fluidized bed esterification reactor, and the catalyst loading is about 300g.

[0094] 1) After the system is replaced with nitrogen, carrier gas nitrogen, carbon dioxide and methanol are introduced into the reactor through the air inlet 21 of the esterification reactor 2, the molar ratio of carbon dioxide and methanol to the raw material liquid methyl furoate is 1.5:1 and 1.5:1 respectively, the flow meter controls the flow rate of carbon dioxide and methanol to be about 50L / min, adjusts the reactor outlet pressure to 1MPa, and fluidizes the catalyst in the fluidized bed esterification reactor 2;

[0095] 2) turning on the auxiliary heating to heat the esterification reactor 2 until the fluidized bed esterification reactor 2 is heated to about 150° C. and stably fluidized;

[0096] 3) The raw material is liquid methyl furoate, the feeding unit 1 is opened, and the feeder 12 is gradually adjusted to control the feeding rate at 30 g / h, and the reaction raw materials are fed into the fluidized bed esterification reactor 2;

[0097] 4) after the methyl furoate and the catalyst are mixed and fluidized in the esterification reactor 2, the methyl furoate is heated and gasified and reacts with methanol in the presence of the catalyst to generate dimethyl 2,5-furandicarboxylate;

[0098] 5) Adjust the space velocity of the raw material methyl furoate to 0.1h -1, when the reaction temperature in the fluidized bed esterification reactor 2 is 180° C. and the pressure is 4 MPa, CO2 is added at a molar ratio of 1.5:1 to the raw material methyl furoate, thereby controlling the conversion rate of furoic acid and the amount of by-products generated;

[0099] 6) The obtained dimethyl 2,5-furandicarboxylate, as well as unreacted methyl furoate and methanol, etc., flow out of the fluidized bed esterification reactor 2 from the top outlet 22 along with nitrogen, pass through the filtering unit 23 to remove a small amount of entrained catalyst fine powder, and then flow out of the reaction device for cooling and collection.

[0100] 7) The deactivated catalyst flows into the regeneration unit 3 through a pipeline connecting the agent outlet 26 at the bottom of the fluidized bed esterification reactor 2 and the catalyst inlet 31 at the top of the regeneration unit 3. The flow rate is controlled by a slide valve on the connecting pipeline. The circulation amount of the regeneration agent is 6-60% of the catalyst storage in the regeneration unit 3 per hour, that is, the catalyst regeneration time is 10-100 minutes. The regenerated catalyst is returned to the fluidized bed esterification reactor 2 under the action of lifting wind through a pipeline connecting the catalyst outlet 32 ​​at the bottom of the regeneration unit 3 and the upper anti-agent outlet 27 in the fluidized bed esterification reactor 2. The specific flow rate is controlled by a slide valve on the connecting pipeline.

[0101] The above carboxylation esterification reaction of methyl furoate was carried out using three catalysts respectively, and the space velocity was 0.01h -1 When the reaction temperature is 180°C and the pressure is 4MPa, the results are as follows:

[0102] Catalyst 1 is SiO2 loaded with 9% K2CO3 + 1% Cs2CO3: methyl furoate conversion rate is 78.5%, dimethyl 2,5-furandicarboxylate selectivity is 94%, and by-product selectivity is 6%. Catalyst 1 is a supported catalyst, SiO2 is a carrier, K2CO3 and Cs2CO3 are active components, and the "9%" in front of K2CO3 means that based on the total weight of the catalyst, the weight percentage of the active component K2CO3 is 9%. The other catalysts in the following embodiments are expressed in the same way.

[0103] Catalyst 2 is SiO2 loaded with 10% K2CO3: methyl furoate conversion rate 75%, dimethyl 2,5-furandicarboxylate selectivity 90%, by-product selectivity 10%.

[0104] Catalyst 3 is SiO2 loaded with 10% Cs2CO3: methyl furoate conversion rate is 89.8%, dimethyl 2,5-furandicarboxylate selectivity is 91%, and by-product selectivity is 9%.

[0105] Embodiment 2:

[0106] The fluidized bed size selected is: reaction section Φ200mm, total length about 1200mm, single-stage pressurized fluidized bed esterification reactor, and the catalyst loading is about 10kg.

[0107] 1) After nitrogen replacement of the system, nitrogen, carbon dioxide and methanol are introduced into the reactor through the air inlet 21 of the esterification reactor 2. The molar ratios of carbon dioxide and methanol to the raw materials are 1.5:1 and 1.5:1, respectively. The flowmeter controls the flow rates of carbon dioxide and methanol to be about 1500 L / min. The pressure of the air outlet 22 is adjusted to 1 MPa to fluidize the catalyst in the fluidized bed esterification reactor 2;

[0108] 2) opening the slide valve on the connecting pipeline between the catalyst regeneration unit 3 and the fluidized bed esterification reactor 2, so that the catalyst forms a circulation transport mode between the fluidized bed esterification reactor 2 and the catalyst regeneration unit 3, and simultaneously opening the control valves on the external catalyst overflow pipe 25-1 and the internal catalyst overflow pipe 25-2 between different reaction sections of the fluidized bed esterification reactor 2, so that the amount of catalyst in each part during the catalyst circulation process is maintained stable;

[0109] 3) Turn on the heating system of the catalyst regeneration unit 3, use the hot catalyst in the regeneration unit 3 to replace the room temperature catalyst in the reactor, so that the temperature of the esterification reactor 2 is increased until the fluidized bed esterification reactor 2 is heated to about 150° C. and stably fluidized. Specifically, the catalyst flows into the regeneration unit 3 through a pipeline connected to the outlet 26 at the bottom of the fluidized bed esterification reactor 2 and the inlet 31 at the top of the regeneration unit 3. The flow rate is controlled by a slide valve on the connecting pipeline. The catalyst entering the regeneration unit 3 is first heated by heat exchange. The catalyst after heat exchange is returned to the fluidized bed esterification reactor 2 through a pipeline connected to the outlet 32 ​​at the bottom of the regeneration unit 3 and the upper anti-drug port 27 in the fluidized bed esterification reactor 2 under the action of lifting wind;

[0110] 4) The raw material is solid furoic acid, the feeding unit 1 is turned on, and the speed of the feeder 12 is gradually adjusted to control the feeding rate, and the reaction raw materials are fed into the fluidized bed esterification reactor 2;

[0111] 5) after furoic acid and the catalyst are mixed and fluidized in the fluidized bed esterification reactor 2, furoic acid is heated and gasified and reacts with methanol in the presence of the catalyst to generate dimethyl 2,5-furandicarboxylate;

[0112] 6) Adjust the space velocity of the raw material furoic acid to 0.01h -1 , when the reaction temperature in the fluidized bed esterification reactor 2 is 280° C., the pressure is 1 MPa, thereby controlling the conversion rate of furoic acid and the amount of by-products generated;

[0113] 7) The obtained dimethyl 2,5-furandicarboxylate, unreacted furoic acid, methanol, etc. flow out of the fluidized bed esterification reactor 2 from the top outlet 22 along with nitrogen, pass through the filtering unit 23 to remove a small amount of entrained catalyst fine powder, and then flow out of the reaction device for cooling and collection.

[0114] The above carboxylation and esterification reactions of furoic acid were carried out using three catalysts respectively, and the space velocity was 0.1h -1 When the reaction temperature is 280°C and the pressure is 1MPa, the results are as follows:

[0115] Catalyst 1 is SiO2 loaded with 9% K2CO3 + 1% Cs2CO3: furoic acid conversion 84.5%, dimethyl 2,5-furandicarboxylate selectivity 90%, by-product selectivity 10%;

[0116] Catalyst 2 is SiO2 loaded with 10% K2CO3: furoic acid conversion 69%, dimethyl 2,5-furandicarboxylate selectivity 89%, by-product selectivity 11%;

[0117] Catalyst 3SiO2 loaded with 10% Cs2CO3: furoic acid conversion 89.8%, dimethyl 2,5-furandicarboxylate selectivity 91%, by-product selectivity 9%;

[0118] Embodiment 3:

[0119] The fluidized bed size selected is: reaction section Φ200mm, total length about 1500mm, two-stage pressurized fluidized bed esterification reactor, and the catalyst is loaded about 4kg in the upper section and 6kg in the lower section.

[0120] 1) After nitrogen replacement of the system, nitrogen, carbon dioxide and methanol are introduced into the reactor through the air inlet 21 of the fluidized bed esterification reactor 2. The molar ratios of carbon dioxide and methanol to the raw materials are 1.5:1 and 1.5:1 respectively. The flowmeter controls the flow rates of carbon dioxide and methanol to be about 1500 L / min. The reactor outlet pressure is adjusted to 1 MPa to fluidize the catalyst in the fluidized bed esterification reactor 2;

[0121] 2) opening the slide valve on the connecting pipeline between the catalyst regeneration unit 3 and the fluidized bed esterification reactor 2, so that the catalyst forms a circulation transport mode in the fluidized bed esterification reactor 2 and the catalyst regeneration unit 3, and simultaneously opening the control valves on the external catalyst overflow pipe 25-1 and the internal catalyst overflow pipe 25-2 between different reaction sections of the fluidized bed esterification reactor 2, so that the amount of catalyst in each part of the two reactors is maintained stable during the catalyst circulation process;

[0122] 3) Turn on the heating system of the catalyst regeneration unit 3, use the hot catalyst in the regeneration unit 3 to replace the room temperature catalyst in the reactor, so as to heat up the fluidized bed esterification reactor 2 until the fluidized bed esterification reactor 2 is heated to about 150° C. and stably fluidized. Specifically, the catalyst flows into the regeneration unit 3 through a pipeline connected with the outlet 26 at the bottom of the fluidized bed esterification reactor 2 and the inlet 31 at the top of the regeneration unit 3. The flow rate is controlled by a slide valve on the connecting pipeline. The catalyst entering the regeneration unit 3 is first heated by heat exchange. The catalyst after heat exchange is returned to the fluidized bed esterification reactor 2 through a pipeline connected with the outlet 32 ​​at the bottom of the regeneration unit 3 and the upper anti-drug port 27 in the fluidized bed esterification reactor 2 under the action of lifting wind;

[0123] 4) the raw material is solid methyl furoate, the feeding unit 1 is turned on, and the speed of the feeder 12 is gradually adjusted to control the feeding rate, and the reaction raw materials are fed into the fluidized bed esterification reactor 2;

[0124] 5) after methyl furoate and the catalyst are mixed and fluidized in the fluidized bed esterification reactor 2, methyl furoate is heated and gasified and reacts with methanol in the presence of the catalyst to generate dimethyl 2,5-furandicarboxylate;

[0125] 6) Adjust the space velocity of the raw material methyl furoate to 0.01h -1 , when the reaction temperature in the fluidized bed esterification reactor 2 is 180° C. and the pressure is 4 MPa, CO2 is added in a molar ratio of 1.5:1 to the raw material methyl furoate, thereby controlling the conversion rate of furoic acid and the amount of by-products generated;

[0126] 7) The generated dimethyl 2,5-furandicarboxylate, unreacted methyl furoate, methanol, etc. flow out of the fluidized bed esterification reactor 2 from the gas phase outlet 22 at the top along with nitrogen, and after passing through the filtering unit 23 to remove a small amount of entrained catalyst fine powder, flow out of the reaction device for cooling and collection.

[0127] The above carboxylation esterification reaction of methyl furoate was carried out using three catalysts respectively, and the space velocity was 0.01h -1 When the reaction temperature is 180°C and the pressure is 4MPa, the results are as follows:

[0128] Catalyst 1 is SiO2 loaded with 9% K2CO3 + 1% Cs2CO3: methyl furoate conversion rate 79.5%, dimethyl 2,5-furandicarboxylate selectivity 93%, phenol selectivity 7%;

[0129] Catalyst 2 is SiO2 loaded with 10% K2CO3: methyl furoate conversion 65%, dimethyl 2,5-furandicarboxylate selectivity 96%, phenol selectivity 4%;

[0130] Catalyst 3SiO2 loaded with 10% Cs2CO3: methyl furoate conversion 89.8%, dimethyl 2,5-furandicarboxylate selectivity 90%, phenol selectivity 10%;

[0131] 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 dimethyl 2,5-furandicarboxylate, characterized in that: It includes a feeding unit, a fluidized bed esterification reactor, and a catalyst regeneration unit; Wherein, the feeding unit is located on one side of the fluidized bed esterification reactor and is used for inputting reaction raw materials, and the raw materials are solid raw materials or liquid raw materials; The fluidized bed esterification 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, and it is an expanded section. The upper and lower diameter ratio is 1.1:1-4:1, 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°. The fluidized bed esterification reactor has at least one feed port, which is connected to the feed unit; a gas outlet is provided at the top for discharging a gas phase mixture; a gas inlet is provided at the bottom for introducing a mixture of methanol and a carrier gas into the reactor; the middle and lower part of the reactor is used as a main reaction zone, in which a single-stage or multi-stage horizontal distribution plate is provided for carrying a catalyst and distributing gas, and at the same time dividing the reaction process 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 reactor to flow from top to bottom; a discharge port is provided on the side of the lower part of the reactor, and a return port is provided on the side of the middle and upper part of the reactor; The catalyst regeneration unit includes a catalyst inlet arranged on the upper side, which is connected to the agent outlet of the fluidized bed esterification reactor through a pipeline, an air inlet is arranged at the bottom of the catalyst regeneration unit and an air outlet is arranged at the top, wherein the air inlet is used to introduce oxygen-containing gas, and the tail gas after regeneration treatment is discharged from the air outlet, and a catalyst outlet is arranged on the lower side of the catalyst regeneration unit, which is connected to the agent return port of the fluidized bed esterification reactor through a pipeline, and the regenerated catalyst is returned to the fluidized bed esterification reactor by the carrier gas to start a new reaction.

2. The device for continuously preparing dimethyl 2,5-furandicarboxylate according to claim 1, characterized in that: When the reaction raw materials are in solid phase, the feeding unit includes a silo and a feeder; When the reaction raw materials are in liquid phase, the feeder includes a storage tank and a feed pump.

3. The device for continuously preparing dimethyl 2,5-furandicarboxylate according to claim 2, characterized in that: When the reaction raw materials are in solid phase, the feeder is selected from a screw feeder or a star feeder; When the reaction raw materials are in liquid phase, a liquid distributor is also arranged in the upper cylindrical structure of the fluidized bed esterification 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 fluidized bed esterification reactor through a pipeline, and the reaction raw materials are transported to the liquid distributor.

4. The device for continuously preparing dimethyl 2,5-furandicarboxylate according to claim 1, characterized in that: The gas outlet of the fluidized bed esterification reactor is connected to a filter, and the filter is used to remove solid particles in the gas phase mixture; the filter includes a screen with corresponding aperture or a cyclone separator.

5. The device for continuously preparing dimethyl 2,5-furandicarboxylate according to claim 1, characterized in that: An external catalyst overflow pipe is arranged on the outer wall of the reactor corresponding to the position of the internal catalyst overflow pipe, which is also used to make the catalyst in the reactor flow from top to bottom, and cooperate with the catalyst transportation between the esterification reactor and the regenerator to form a complete catalyst circulation process.

6. The device for continuously preparing dimethyl 2,5-furandicarboxylate according to claim 1, characterized in that: The distribution plate arranged in the fluidized bed esterification reactor includes a porous plate, a sieve plate, and a bubble cap plate.

7. The device for continuously preparing dimethyl 2,5-furandicarboxylate according to claim 1, characterized in that: A gas distributor is disposed inside the lower part of the catalyst regeneration unit and is connected to the gas inlet for maintaining uniform distribution of gas flow inside the catalyst regeneration unit.

8. The device for continuously preparing dimethyl 2,5-furandicarboxylate according to claim 1, characterized in that: A slide valve is installed on the connecting pipeline between the catalyst inlet of the catalyst regeneration unit and the catalyst outlet of the fluidized bed esterification reactor for adjusting and controlling the catalyst flow between the fluidized bed esterification reactor and the catalyst regeneration unit.

9. The device for continuously preparing dimethyl 2,5-furandicarboxylate according to claim 1, characterized in that: A slide valve is installed on the connecting pipeline between the catalyst outlet of the catalyst regeneration unit and the return port of the fluidized bed esterification reactor for adjusting and controlling the catalyst flow between the fluidized bed esterification reactor and the catalyst regeneration unit.

10. The device for continuously preparing dimethyl 2,5-furandicarboxylate according to claim 7, characterized in that: The gas distributor in the catalyst regeneration unit includes a porous tube, a porous plate, a sieve plate, and a bubble plate.

11. The device for continuously preparing dimethyl 2,5-furandicarboxylate according to claim 1, characterized in that: An exchange / heating system is arranged outside the catalyst regeneration unit and around the catalyst regeneration unit, and is used for exchanging heat or heating the catalyst regeneration unit.

12. The device for continuously preparing dimethyl 2,5-furandicarboxylate according to claim 1, characterized in that: When the catalyst in the fluidized bed esterification reactor needs to be regenerated, the air inlet at the bottom and the air outlet at the top of the regeneration unit are first opened, and then the agent outlet of the esterification reactor and the catalyst inlet of the regeneration unit are connected, so that the catalyst to be regenerated enters the regeneration unit with the carrier gas, and the catalyst reacts with the oxygen-containing gas in the regeneration unit to remove the carbon material deposited on the surface of the catalyst to complete the catalyst regeneration, and the tail gas is discharged from the top air outlet of the regeneration unit, and the regenerated catalyst is sent to the agent return port of the esterification reactor through the catalyst outlet of the regeneration unit to start a new reaction.

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