Device and method for preparing 5-hydroxymethylfurfural through continuous sugar dehydration

Abstract

The invention belongs to the technical field of catalytic chemistry and biomass resource utilization, and particularly discloses a device and method for preparing 5-hydroxymethylfurfural through continuous sugar dehydration. The device comprises a storage tank, a raw material tank and a reaction mechanism; the surface of the conveying pipe is provided with a first pump body for pumping the extraction agent stored in the storage tank into the reaction mechanism; the raw materials are conveyed from top to bottom, and the extraction agent is conveyed from bottom to top, so that the descending raw materials are in contact with the catalyst, and a dehydration reaction is carried out to generate 5-HMF; the generated 5-HMF is immediately extracted by rising extractant liquid drops to enter an organic phase, the retention time of the 5-HMF in a water phase is greatly shortened by in-situ extraction, side reaction is effectively inhibited, the mass transfer efficiency is maximized by countercurrent operation, and the mode can effectively avoid the problems of low production efficiency and low production cost of a traditional reaction mode. The product in the water phase is extracted by the organic phase, so that the excessive reaction is avoided, the product yield is improved, and the production efficiency of the product is improved by the continuous process.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic chemistry and biomass resource utilization, and specifically discloses a device and a method for preparing 5-hydroxymethylfurfural by continuous sugar dehydration. Background Art

[0002] 5-Hydroxymethylfurfural (HMF), as an important intermediate compound connecting biomass and chemical raw materials, can be synthesized into a series of other high-value-added furan derivatives, such as 2,5-furandicarboxylic acid and 2,5-tetrahydrofuran dimethanol, through chemical reactions such as hydrogenation, oxidation, etherification, and esterification. It has great application prospects and value. At present, the main methods for preparing 5-HMF are: (1) direct dehydration of fructose; (2) isomerization of glucose followed by dehydration; (3) hydrolysis of cellulose followed by synthesis of 5-HMF, and the reaction is mainly carried out in an intermittent reactor, which has low production efficiency and complex operation. Therefore, those skilled in the art have proposed a device and method for continuously dehydrating sugar to prepare 5-hydroxymethylfurfural. Summary of the Invention

[0003] In view of this, the technical problem to be solved by the present invention is to propose a device and method for continuously dehydrating sugar to prepare 5-hydroxymethylfurfural, so as to solve the problems of low production efficiency and discontinuous reaction in the existing technology.

[0004] To achieve the above objectives, the present invention provides an apparatus and method for continuously dehydrating sugar to prepare 5-hydroxymethylfurfural, comprising a storage tank, a raw material tank, and a reaction mechanism, wherein a delivery pipe is connected to the surface of the storage tank, and a first pump body is provided on the surface of the delivery pipe for pumping an extractant stored in the storage tank into the reaction mechanism, a gas injection pipe is connected to the surface of the delivery pipe, a material delivery pipe is connected to the surface of the raw material tank, and a second pump body is provided on the surface of the material delivery pipe for pumping the raw material in the raw material tank into the reaction mechanism, a vacuum distillation tower is provided on one side of the reaction mechanism, a product tank is connected to the bottom of the vacuum distillation tower, a recovery pipe is connected to the top of the vacuum distillation tower, an output pipe is connected to the surface of the vacuum distillation tower, and the other end of the output pipe is connected to the reaction mechanism, an extractant recovery tank connected to the other end of the recovery pipe is provided on one side of the vacuum distillation tower, and a third pump body is provided on one side of the extractant recovery tank for introducing the extractant recovered in the extractant recovery tank into the storage tank; The raw materials are fed into the reaction mechanism from the raw material tank from top to bottom, the extractant is fed into the reaction mechanism from the storage tank from bottom to top, the product formed in the reaction mechanism is fed into the vacuum distillation tower for separation to obtain the extractant and the product 5-HMF, the extractant is stored in the extractant recovery tank and pumped into the storage tank for reuse through the third pump body, and the product 5-HMF is stored in the product tank.

[0005] In the above technical solution, preferably, the reaction mechanism includes a reactor, a temporary storage reactor is provided on the top of the reactor, the top of the reactor is connected to a discharge pipe, the upper end of the discharge pipe is connected to the temporary storage reactor, the bottom of the reactor is connected to a waste liquid pipe, the bottom of the temporary storage reactor is connected to a discharge pipe, and an auxiliary component is provided inside the reactor.

[0006] In the above technical solution, preferably, one end of the delivery pipe is connected to the lower end of the surface of the reactor, and one end of the material delivery pipe is connected to the upper end of the surface of the reactor.

[0007] In the above technical solution, preferably, the auxiliary component includes a plurality of tower plates, and the plurality of tower plates are evenly fixedly connected to the inner wall of the reactor from top to bottom. The center of the tower plates forms a passing zone, and the surface of the passing zone is provided with evenly distributed sieve holes, and a reaction zone is formed between two adjacent tower plates.

[0008] In the above technical solution, preferably, the surface of the tower plate is connected with a draft tube, the lower end of the draft tube passes through the tower plate and is connected with the adjacent reaction zone below, and the upper end of the draft tube is flush with the top surface of the tower plate.

[0009] In the above technical solution, preferably, the guide pipes arranged on the two adjacent tower plates are symmetrically arranged, and the top of the tower plate is fixedly connected with a cofferdam, the cofferdam is annular, and the inner side of the cofferdam is connected to the guide pipe.

[0010] In the above technical solution, preferably, evenly distributed partitions are provided on the top of the tower plate, both ends of the partitions are fixedly connected to the inner wall of the reactor, and evenly distributed through holes are opened on the surface of the partitions.

[0011] A method for preparing 5-hydroxymethylfurfural by continuous sugar dehydration comprises the following steps: S1. The prepared sugar aqueous solution raw material is stored in the raw material tank, and the extractant is stored in the storage tank. The extractant and raw material are pumped into the interior of the reaction mechanism through the first pump body and the second pump body; S2. After the reaction is completed, the generated organic phase can be temporarily stored in the temporary storage kettle, and the final gravity sedimentation separation can be carried out here. The separated organic extractant is discharged separately through the output pipe, and the aqueous phase is discharged separately through the discharge pipe, thereby improving the product purity and reducing the subsequent processing time of entering the vacuum distillation tower; S3, the organic phase entering the vacuum distillation tower is separated by the vacuum distillation tower to obtain the extractant and the product, and the recovered extractant is pumped into the storage tank through the third pump body for recycling; S4. The product is introduced into the internal storage of the product tank, while the waste liquid and water phase generated during the reaction of the reaction mechanism are discharged separately.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. By conveying the raw material from top to bottom and the extractant from bottom to top, the descending raw material contacts the catalyst, causing a dehydration reaction to produce 5-HMF. The generated 5-HMF is immediately extracted into the organic phase by the ascending extractant droplets. This in-situ extraction significantly reduces the residence time of 5-HMF in the aqueous phase, effectively suppressing side reactions. The countercurrent operation maximizes mass transfer efficiency, effectively avoiding the low production efficiency of traditional reaction methods. The organic phase extracts the product in the aqueous phase, avoiding overreaction and improving product yield. The continuous process also improves product production efficiency.

[0013] 2. By providing auxiliary components, the extractant is sheared into tiny droplets when passing through the sieve holes. Since the density is lower than that of the aqueous phase, the extractant naturally floats upward. In addition, the cofferdam prevents the extractant from being carried by the raw material flow through the draft tube and discharged into the interior of the lower reaction zone. At the same time, the partitions and through holes can further shear the tiny droplets of the extractant, forming finer droplets to enhance the extraction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 Schematic cross-section of the reaction mechanism of the present invention; Figure 3 Schematic diagram of the connection between the tower plate and the reactor of the present invention; Figure 4 Schematic cross-section of the reactor of the present invention; Figure 5 Schematic diagram of the distribution of partitions and trays of the present invention; Figure 6 It is a schematic diagram of the process of the present invention; Figure 7 It is a schematic diagram of the process flow of the present invention.

[0015] In the figure: 1. Storage tank; 101. Gas injection pipe; 102. Delivery pipe; 103. First pump body; 2. Raw material tank; 201. Delivery pipe; 202. Second pump body; 3. Reaction mechanism; 301. Reactor; 302. Waste liquid pipe; 303. Temporary storage kettle; 304. Discharge pipe; 305. Discharge pipe; 31. Auxiliary component; 3101. Tower plate; 3102. Sieve hole; 3103. Draft pipe; 3104. Partition; 3105. Through hole; 3106. Cofferdam; 4. Output pipe; 5. Vacuum distillation tower; 501. Product tank; 6. Recovery pipe; 7. Extractant recovery tank; 701. Third pump body. DETAILED DESCRIPTION

[0016] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0018] like Figure 1-Figure 7 The device and method for continuously dehydrating sugar to prepare 5-hydroxymethylfurfural include a storage tank 1, a raw material tank 2, and a reaction mechanism 3. The surface of the storage tank 1 is connected to a delivery pipe 102, and the surface of the delivery pipe 102 is provided with a first pump body 103 for pumping the extractant stored in the storage tank 1 into the reaction mechanism 3. The surface of the delivery pipe 102 is connected to an air injection pipe 101. The surface of the raw material tank 2 is connected to a delivery pipe 201, and the surface of the delivery pipe 201 is provided with a second pump body 103 for pumping the raw material in the raw material tank 2 into the reaction mechanism 3. A vacuum distillation tower 5 is provided on one side of the reaction mechanism 3. The bottom of the vacuum distillation tower 5 is connected to a product tank 501. The top of the vacuum distillation tower 5 is connected to a recovery pipe 6. The surface of the vacuum distillation tower 5 is connected to an output pipe 4. The other end of the output pipe 4 is connected to the reaction mechanism 3. An extractant recovery tank 7 connected to the other end of the recovery pipe 6 is provided on one side of the vacuum distillation tower 5. A third pump body 701 is provided on one side of the extractant recovery tank 7 for introducing the extractant recovered in the extractant recovery tank 7 into the storage tank 1. The raw materials are fed from the raw material tank 2 into the reaction mechanism 3 from top to bottom, and the extractant is fed from the storage tank 1 into the reaction mechanism 3 from bottom to top. The product formed in the reaction mechanism 3 is fed into the vacuum distillation tower 5 for separation to obtain the extractant and 5-HMF. The extractant is stored in the extractant recovery tank 7 and pumped into the storage tank 1 for reuse by the third pump body 701. The product 5-HMF is stored in the product tank 501.

[0019] The raw materials and the extractant are synchronously transported to the interior of the reaction mechanism 3 by the first pump body 103 and the second pump body 202 for reaction. The interior of the reactor 301 is filled with a catalyst. Specifically, the raw materials are glucose, fructose or fructose-glucose syrup as raw materials, and water is used as a solvent to prepare a sugar aqueous solution; The extractant includes tetrahydrofuran, alkylphenol, n-butanol and dimethyl sulfoxide, etc., preferably tetrahydrofuran.

[0020] The product after treatment by the reaction mechanism 3 is introduced into the interior of the vacuum distillation tower 5 through the output pipe 4, and is separated by the vacuum distillation tower 5 to obtain the extractant and the product. The product is introduced into the interior of the product tank 501 for storage, and the recovered extractant can be pumped into the interior of the storage tank 1 for recycling.

[0021] like Figures 1-6 As shown, the reaction mechanism 3 includes a reactor 301, a temporary storage reactor 303 is provided on the top of the reactor 301, the top of the reactor 301 is connected to a discharge pipe 305, the upper end of the discharge pipe 305 is connected to the temporary storage reactor 303, the bottom of the reactor 301 is connected to a waste liquid pipe 302, the bottom of the temporary storage reactor 303 is connected to a discharge pipe 304, and an auxiliary component 31 is provided inside the reactor 301.

[0022] One end of the delivery pipe 102 is connected to the lower end of the surface of the reactor 301 , and one end of the material delivery pipe 201 is connected to the upper end of the surface of the reactor 301 .

[0023] The raw material is injected from the top of the reactor 301 downward through the feed pipe 201, while the extractant is injected from the bottom of the reactor 301 upward through the feed pipe 102 to react. After a period of equilibrium, the reaction maintains a state in which the upper layer is an organic layer containing the product and the lower layer is an aqueous layer. The upper organic layer containing the product can be introduced into the interior of the temporary tank 303 through the discharge pipe 305, thereby providing sufficient residence time and space for the organic layer, allowing the mixture discharged from the top of the reactor 301 (mainly the light organic extractant phase and the heavy aqueous phase) to undergo final gravity sedimentation separation. The further separated organic extractant is discharged separately through the output pipe 4, and the aqueous phase is discharged separately through the discharge pipe 304. This improves the purity of the product and reduces the subsequent processing time in the vacuum distillation column 5.

[0024] like Figures 1-6 As shown, the auxiliary component 31 includes a plurality of tower plates 3101, which are evenly fixed to the inner wall of the reactor 301 from top to bottom. The center of the tower plate 3101 forms a passing zone, and the surface of the passing zone is provided with evenly distributed sieve holes 3102. A reaction zone is formed between two adjacent tower plates 3101.

[0025] The surface of the tower plate 3101 is connected to a draft tube 3103 , the lower end of the draft tube 3103 passes through the tower plate 3101 and is connected to the adjacent reaction zone below, and the upper end of the draft tube 3103 is flush with the top surface of the tower plate 3101 .

[0026] The flow guide pipes 3103 provided on two adjacent tower plates 3101 are symmetrically arranged, and a cofferdam 3106 is fixedly connected to the top of the tower plate 3101. The cofferdam 3106 is annular, and the inner side of the cofferdam 3106 is connected to the flow guide pipe 3103.

[0027] The top of the tower plate 3101 is provided with evenly distributed partitions 3104 . Both ends of the partitions 3104 are fixedly connected to the inner wall of the reactor 301 . Evenly distributed through holes 3105 are opened on the surface of the partitions 3104 .

[0028] Because the raw material is transported from top to bottom while the extractant is transported in the opposite direction, the descending raw material comes into contact with the catalyst, undergoing a dehydration reaction to produce 5-HMF. The generated 5-HMF is immediately extracted into the organic phase by the rising extractant droplets. This method effectively avoids the low production efficiency of traditional reaction methods. The organic phase extracts the product in the aqueous phase, avoiding overreaction and improving product yield. At the same time, the continuous process improves product production efficiency. The downward raw material can be introduced into the interior of the reaction zone below through the draft tube 3103. Since the draft tubes 3103 provided on two adjacent trays 3101 are symmetrically arranged, the raw material can pass through the reaction zone and be introduced into the interior of the next reaction zone from the other draft tube 3103. The extractant can fully contact the raw material during its ascent through the sieve holes 3102, thereby extracting the generated 5-HMF. When the extractant passes through the sieve holes 3102, it is sheared into tiny droplets, which naturally float upward because their density is lower than that of the aqueous phase. The provision of the cofferdam 3106 can prevent the extractant from being carried by the raw material flow through the draft tube 3103 and discharged into the interior of the lower reaction zone. At the same time, the provision of the partition 3104 and the through hole 3105 can further shear the tiny droplets sheared by the extractant, so that they can form finer droplets to enhance the extraction effect.

[0029] A method for preparing 5-hydroxymethylfurfural by continuous sugar dehydration comprises the following steps: S1, the prepared sugar aqueous solution raw material is stored in the raw material tank 2, and the extractant is stored in the storage tank 1, and the extractant and raw material are pumped into the interior of the reaction mechanism 3 through the first pump body 103 and the second pump body 202; S2. After the reaction is completed, the generated organic phase can be temporarily stored in the temporary storage kettle 303, and can be subjected to final gravity sedimentation separation here. The separated organic extractant is discharged separately through the output pipe 4, and the aqueous phase is discharged separately through the discharge pipe 304, thereby improving the product purity and reducing the subsequent processing time of entering the vacuum distillation tower 5; S3, the organic phase entering the vacuum distillation tower 5 is separated into the extractant and the product by the vacuum distillation tower 5, and the recovered extractant is pumped into the storage tank 1 through the third pump body 701 for recycling; S4. The product is introduced into the internal storage of the product tank 501, while the waste liquid and the aqueous phase generated during the reaction process of the reaction mechanism 3 are discharged separately.

[0030] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. Various changes and improvements are possible without departing from the spirit and scope of the present invention, and such changes and improvements fall within the scope of the invention as claimed.

Claims

1. A device for continuously dehydrating sugar to prepare 5-hydroxymethylfurfural, comprising a storage tank (1), a raw material tank (2) and a reaction mechanism (3), characterized in that: The surface of the storage tank (1) is connected to a delivery pipe (102), and the surface of the delivery pipe (102) is provided with a first pump body (103) for pumping the extractant stored in the storage tank (1) into the reaction mechanism (3). The surface of the delivery pipe (102) is connected to an air injection pipe (101). The surface of the raw material tank (2) is connected to a delivery pipe (201), and the surface of the delivery pipe (201) is provided with a second pump body (202) for pumping the raw material in the raw material tank (2) into the reaction mechanism (3). A vacuum distillation tower (5 ), the bottom of the vacuum distillation tower (5) is connected to a product tank (501), the top of the vacuum distillation tower (5) is connected to a recovery pipe (6), the surface of the vacuum distillation tower (5) is connected to an output pipe (4), the other end of the output pipe (4) is connected to the reaction mechanism (3), one side of the vacuum distillation tower (5) is provided with an extractant recovery tank (7) connected to the other end of the recovery pipe (6), and one side of the extractant recovery tank (7) is provided with a third pump body (701) for introducing the extractant recovered in the extractant recovery tank (7) into the storage tank (1); The raw materials are fed from the raw material tank (2) into the reaction mechanism (3) from top to bottom, the extractant is fed from the storage tank (1) into the reaction mechanism (3) from bottom to top, the product formed in the reaction mechanism (3) is fed into the vacuum distillation tower (5) for separation to obtain the extractant and the product 5-HMF, the extractant is fed into the extractant recovery tank (7) for storage and is pumped into the storage tank (1) for reuse through the third pump body (701), and the product 5-HMF is fed into the product tank (501) for storage.

2. The device for preparing 5-hydroxymethylfurfural by continuous sugar dehydration according to claim 1, characterized in that: The reaction mechanism (3) comprises a reactor (301), a temporary storage reactor (303) is provided on the top of the reactor (301), the top of the reactor (301) is connected to a discharge pipe (305), the upper end of the discharge pipe (305) is connected to the temporary storage reactor (303), the bottom of the reactor (301) is connected to a waste liquid pipe (302), the bottom of the temporary storage reactor (303) is connected to a discharge pipe (304), and an auxiliary component (31) is provided inside the reactor (301).

3. The device for preparing 5-hydroxymethylfurfural by continuous sugar dehydration according to claim 2, characterized in that: One end of the delivery pipe (102) is connected to the lower end of the surface of the reactor (301), and one end of the material delivery pipe (201) is connected to the upper end of the surface of the reactor (301).

4. The device for preparing 5-hydroxymethylfurfural by continuous sugar dehydration according to claim 3, characterized in that: The auxiliary component (31) includes a plurality of tower plates (3101), and the plurality of tower plates (3101) are evenly fixedly connected to the inner wall of the reactor (301) from top to bottom. The center of the tower plates (3101) forms a passing zone, and the surface of the passing zone is provided with evenly distributed sieve holes (3102). A reaction zone is formed between two adjacent tower plates (3101).

5. The device for preparing 5-hydroxymethylfurfural by continuous sugar dehydration according to claim 4, characterized in that: The surface of the tower plate (3101) is connected to a flow guide tube (3103), the lower end of the flow guide tube (3103) passes through the tower plate (3101) and is connected to the adjacent reaction zone below, and the upper end of the flow guide tube (3103) is flush with the top surface of the tower plate (3101).

6. The device for preparing 5-hydroxymethylfurfural by continuous sugar dehydration according to claim 5, characterized in that: The guide pipes (3103) provided on the two adjacent tower plates (3101) are symmetrically arranged, and the top of the tower plate (3101) is fixedly connected with a cofferdam (3106), the cofferdam (3106) is annular, and the inner side of the cofferdam (3106) is connected to the guide pipe (3103).

7. The device for preparing 5-hydroxymethylfurfural by continuous sugar dehydration according to claim 6, characterized in that: A uniformly distributed partition (3104) is provided on the top of the tower plate (3101), both ends of the partition (3104) are fixedly connected to the inner wall of the reactor (301), and a uniformly distributed through hole (3105) is opened on the surface of the partition (3104).

8. A method for preparing 5-hydroxymethylfurfural by continuous dehydration of sugar, applied to the apparatus for preparing 5-hydroxymethylfurfural by continuous dehydration of sugar according to any one of claims 2 to 7, characterized in that: The method comprises the following steps: S1, the prepared sugar aqueous solution raw material is stored in the raw material tank (2), and the extractant is stored in the storage tank (1), and the extractant and raw material are pumped into the interior of the reaction mechanism (3) through the first pump body (103) and the second pump body (202); S2. After the reaction is completed, the generated organic phase can be temporarily stored in the temporary storage kettle (303) and can be finally separated by gravity sedimentation. The separated organic extractant is discharged separately through the output pipe (4), and the aqueous phase is discharged separately through the discharge pipe (304), thereby improving the purity of the product and reducing the subsequent processing time of entering the vacuum distillation tower (5); S3, the organic phase entering the vacuum distillation tower (5) is separated into an extractant and a product by the vacuum distillation tower (5), and the recovered extractant is pumped into the storage tank (1) through the third pump body (701) for recycling; S4. The product is introduced into the internal storage of the product tank (501), while the waste liquid and the aqueous phase generated during the reaction of the reaction mechanism (3) are discharged separately.

Images