Equipment for preparing polymer-grade tetrahydrofuran from residues and use method

Abstract

The invention discloses equipment for preparing polymer-grade tetrahydrofuran from residues and a using method, and relates to the technical field of chemical engineering, the equipment for preparing the polymer-grade tetrahydrofuran from the residues and the using method, the equipment comprises a BDO light component removal tower, a BDO reactor and a THF dehydration tower, the side face of the BDO light component removal tower is connected with a multi-stage rectification tank through a condensation pipe, the structure of a BDO light component removal tower in the prior art is improved, a plurality of rectification tanks connected through condensation pipes are arranged, heating rectification in multiple temperature intervals is carried out through heat energy of a tar leading-out pump, and different components are purified according to the boiling point difference of all impurity components; the tetrahydrofuran prepared from the residues contains few impurities by finely controlling the rectification temperature, the tetrahydrofuran can be conveniently introduced into a THF dehydration tower to be directly purified into polymer-grade tetrahydrofuran with the purity of 99% or above, in addition, rectification residual liquid is introduced into a feeding pipe to dilute feeding tar, waste heat is effectively recycled, and meanwhile the energy consumption is reduced. And environmental pollution caused by component emission can be avoided.

Description

Technical Field

[0001] This invention relates to equipment for preparing polymer-grade tetrahydrofuran, and more specifically to equipment and methods for preparing polymer-grade tetrahydrofuran from residues. Background Technology

[0002] BDO is an important chemical raw material. The production of BDO produces tar, a byproduct that mainly contains BDO, THF, methanol, butanol and ethanol. THF in BDO tar is one of the strongest polar ethers. It is not only an important raw material for organic synthesis, but also a high-performance solvent with a wide range of applications.

[0003] Extracting THF from BDO tar can improve resource utilization. However, the amount of water evaporated in the BDO dehydration tower is large, resulting in a high water content in the distilled tetrahydrofuran mixture. Tetrahydrofuran mixed with a large amount of water cannot achieve a purification effect of over 99% through a single dehydration tower. Consequently, the produced tetrahydrofuran cannot be directly used in chemical production and requires subsequent complex distillation, hydrogenation, and re-distillation steps for impurity removal. If the structure of the existing BDO dehydration tower can be improved to minimize the water content of the produced tetrahydrofuran, the purity of the tetrahydrofuran directly output from the system will be greatly improved.

[0004] To address this, those skilled in the art have proposed an apparatus and method for preparing polymer-grade tetrahydrofuran from residues. This method modifies the structure of existing BDO dehydration towers, effectively utilizing the heat energy of the distillate gas phase as a heating source and facilitating temperature control of the distillate gas phase. This also helps to minimize the water content of the gas phase, achieving the desired effect of directly producing polymer-grade tetrahydrofuran from the system. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides equipment and methods for preparing polymer-grade tetrahydrofuran from residues. By improving the existing BDO light-removal tower structure, different impurity components in the tar are distilled at different temperature ranges in the BDO light-removal tower. The obtained THF component has a lower content of other impurities, which facilitates the purification and preparation of tetrahydrofuran in the subsequent THF dehydration tower process, resulting in polymer-grade tetrahydrofuran with a purity of over 99%.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an apparatus for preparing polymer-grade tetrahydrofuran from residue, comprising a BDO light-removal tower for heating and removing light-removal from BDO tar, a BDO reactor connected to the BDO light-removal tower for processing and purifying the light-removed BDO tar, and a THF dehydration tower connected to the BDO light-removal tower for further purification of the separated tetrahydrofuran, ensuring that the purity of the tetrahydrofuran product reaches 99% or higher.

[0007] A feed pipe is fixed to the side of the BDO light tar removal tower. Diluted BDO tar is fed into the BDO light tar removal tower for heating through the feed pipe. A condenser is connected to the side of the top of the BDO light tar removal tower. The evaporated impurity gas is discharged from the BDO light tar removal tower through the condenser.

[0008] The end of the condenser tube away from the side wall of the BDO light content removal tower is fixedly connected to a distillation tank. The evaporated mixed gas exchanges heat with the input material through the condenser tube. The medium in the condenser tube cools down and condenses, and is stored in the distillation tank in stages. In the distillation tank, the condensate is heated and distilled in multiple temperature ranges. Distillation in multiple temperature ranges can separate components with different boiling points, reduce the impurity content in the obtained tetrahydrofuran, and facilitate the subsequent processing of the THF dehydration tower to produce polymer-grade tetrahydrofuran. The remaining liquid after distillation is returned to the feed pipe for dilution of the feed tar.

[0009] Preferably, a baffle is fixedly connected to the bottom of the BDO light-removal tower, the feed pipe is connected to the top of the baffle, and a tar discharge pump is fixedly connected to the side of the BDO light-removal tower and below the baffle. The tar discharge pump is connected to the BDO reactor, and the BDO tar that has undergone light-removal is input into the BDO reactor for subsequent purification treatment.

[0010] The baffle plate is inclined and fixed to the inner wall of the bottom of the BDO light tar removal tower to block the tar discharge pump, thus preventing the diluted tar input into the BDO light tar removal tower through the feed pipe from being directly discharged through the tar discharge pump before being heated to the light tar removal temperature.

[0011] A heating plate is provided on the inner side of the partition. The diluted tar entering the BDO light tar removal tower is heated to the light tar removal temperature by the heating plate. The tar discharge pump is set in parallel with the distillation tank to facilitate heat exchange between the materials being transported by the two.

[0012] Preferably, a heat exchange box is fixedly connected to the side wall of the BDO light-light removal tower, and the heat exchange box provides protection for the high-temperature structure outside the BDO light-light removal tower.

[0013] Preferably, the tar discharge pump extends into the heat exchange box to reheat the material input through the feed pipe and the condensate returning from the distillation tank. As the heat exchange proceeds, the temperature of the tar in the tar discharge pump gradually decreases, thereby achieving heating and distillation in different temperature ranges of different distillation tanks. This allows for the separation of components with different boiling points by temperature, reducing the impurity content in the extracted tetrahydrofuran.

[0014] Preferably, the tar discharge pump and the condenser tube convey material in the same direction, both of which output hot materials, facilitating the installation of the feed pipe.

[0015] A heat exchange plate is fixedly connected to the side of the tar discharge pump and closely attached to the lower surface of the distillation tank. The heat exchange plate enables heat exchange between the tar discharge pump and the material in the distillation tank.

[0016] Preferably, multiple condenser tubes are sequentially and obliquely connected between adjacent distillation tanks. The obliquely arranged condenser tubes facilitate the reflux of condensed liquid. Multiple distillation tanks are connected in series through condenser tubes to form a continuous distillation structure with different temperature ranges.

[0017] The material conveying direction of the feed pipe is opposite to that of the condenser pipe, and a heat exchange pipe is fixedly connected to the middle section of the feed pipe corresponding to the condenser pipe. The heat exchange pipe extends to the condenser pipe and the tar discharge pump and is set parallel to the condenser pipe. Heat exchange is performed between the condenser pipe and the tar discharge pump through the heat exchange pipe.

[0018] A stirring element is provided at the beginning of the feed pipe. The liquid remaining after distillation in the distillation tank is returned to the beginning of the feed pipe. The stirring element mixes the tar material with the liquid remaining after distillation, thereby diluting the material.

[0019] Preferably, a reflux pipe is connected sequentially between the multiple sets of distillation tanks, and a pressure valve is provided on the side of the reflux pipe. When the liquid accumulated in each distillation tank exceeds a certain amount, the liquid pressure in the distillation tank exceeds the limit set by the pressure valve, triggering the pressure valve to open and introduce the liquid in the previous distillation tank into the next distillation tank. The multi-stage distillation method can maximize the purification effect of each stage of the distillation.

[0020] Preferably, one of the distillation tanks has a discharge pipe connected through to its top. The distillation tank is connected to the THF dehydration tower via the discharge pipe. The tetrahydrofuran obtained from the distillation is discharged into the THF dehydration tower through the discharge pipe connected to the THF dehydration tower. The tetrahydrofuran obtained after multi-stage distillation has a lower impurity content, which makes it easier to directly purify it into polymer-grade tetrahydrofuran with a purity of over 99% through the subsequent THF dehydration tower.

[0021] Preferably, the bottom of the nearest distillation tank connected to the BDO light-light removal tower is connected to an outlet pipe. The distillation tank is connected to the beginning of the feed pipe through the outlet pipe. The main component of the liquid remaining after distillation is liquid water. The liquid remaining after distillation is introduced into the beginning of the feed pipe through the outlet pipe for dilution of the feed tar. This effectively utilizes the waste heat of distillation, avoids pollution from component discharge, facilitates the light-light removal treatment of tar by the BDO light-light removal tower, and prevents agglomeration in the BDO light-light removal tower from affecting material conveying.

[0022] The method of using the equipment for preparing polymer-grade tetrahydrofuran from residues, and the preparation process are as follows:

[0023] S1. BDO tar is fed into the BDO light-light removal tower through the feed pipe. The BDO tar is heated by the heating plate in the BDO light-light removal tower. The THF, methanol, butanol and ethanol in the BDO tar absorb heat and evaporate. The evaporated mixed gas is output from the BDO light-light removal tower through the condenser.

[0024] S2. The mixed gas output through the condenser exchanges heat with the tar in the feed pipe, the mixed gas cools down and adheres to the inner wall of the condenser to condense, and the condensate enters the distillation tank along the condenser.

[0025] S3. The condensate in each stage of the distillation tank is heated and distilled at different temperature ranges by the tar discharge pump. Different components are separated sequentially under distillation at different temperature ranges and transported to specific areas along the corresponding pipelines. The main component of the liquid remaining after distillation is liquid water, which is introduced into the starting end of the feed pipe through the discharge pipe. Combined with the agitator, the input tar is diluted. The diluted tar is prevented from agglomerating during heating and affecting the flow.

[0026] This invention discloses an apparatus and method for preparing polymer-grade tetrahydrofuran from residues, which has the following beneficial effects:

[0027] 1. The equipment and method for preparing polymer-grade tetrahydrofuran from the residue involves structural improvements to the existing BDO light component removal tower. Multiple distillation tanks connected by condenser tubes are incorporated. Heat from the tar extraction pump is used for multi-stage temperature distillation. Different components are purified based on their boiling points. By precisely controlling the distillation temperature, the resulting tetrahydrofuran contains fewer impurities, facilitating direct purification into a THF dehydration tower to produce polymer-grade tetrahydrofuran with a purity of over 99%.

[0028] 2. The equipment and method for preparing polymer-grade tetrahydrofuran from the residue: The bottom of the BDO light-light removal tower is fixed with a baffle to separate the feed pipe from the tar discharge pump, so as to prevent the tar introduced into the BDO light-light removal tower from being discharged directly without heating, thereby slowing down the tar introduced into the BDO light-light removal tower, so as to facilitate heating the tar to the light-light removal temperature through the heating plate and outputting it outward in an orderly manner.

[0029] 3. The equipment and method for preparing polymer-grade tetrahydrofuran from the residue involves connecting multiple distillation tanks in series using multi-section condenser tubes. The mixed gas exiting through the condenser tubes exchanges heat with the material in the feed pipe, condenses, and flows back to the distillation tanks at different levels. Then, the condensate in the different distillation tanks is heated and distilled at different temperature ranges using a tar discharge pump. Different components are distilled out according to their boiling points and discharged from the equipment to obtain tetrahydrofuran with high purity.

[0030] 4. The equipment and method for preparing polymer-grade tetrahydrofuran from the residue: The distillation residue is introduced into the starting end of the feed pipe through the outlet pipe, and a stirrer is set at the starting end of the feed pipe. The residue is used to stir and dilute the tar introduced into the system. On the one hand, the waste heat is fully utilized to preheat the tar, and on the other hand, the components in the tar are prevented from being discharged and causing environmental pollution. At the same time, the diluted tar is not easy to clump after being heated and de-lightened, which will affect the operation of the equipment. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0033] Figure 2 This is a schematic diagram of the external segmented distillation structure of the BDO light-removal tower of the present invention;

[0034] Figure 3 This is a schematic diagram illustrating the installation of internal partitions and the partitioning of the internal space in the BDO light tower of the present invention.

[0035] Figure 4 This is a schematic diagram of the preheating and interconnected layout of the various pipes in this invention;

[0036] Figure 5 This is a schematic diagram of the reflux and material output structure between adjacent distillation tanks of the present invention.

[0037] In the diagram: 1. BDO light oil removal tower; 2. BDO reactor; 3. THF dehydration tower; 4. Feed pipe; 5. Condenser; 6. Distillation tank; 7. Baffle plate; 8. Tar removal pump; 9. Heat exchanger; 10. Heating plate; 11. Heat exchange disc; 12. Heat exchange tube; 13. Stirring element; 14. Reflux pipe; 15. Pressure valve; 16. Discharge pipe; 17. Outlet pipe. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] This invention discloses an apparatus and a method for preparing polymer-grade tetrahydrofuran from residues;

[0040] According to the appendix Figure 1 As shown, the system includes a BDO light-weight removal tower 1, a BDO reactor 2 connected to the BDO light-weight removal tower 1, and a THF dehydration tower 3 connected to the BDO light-weight removal tower 1. BDO tar is fed into the BDO light-weight removal tower 1, where it is heated to remove light-weight components. The BDO tar that has undergone light-weight removal is then fed into the BDO reactor 2 for further processing. The tetrahydrofuran evaporated from the BDO tar enters the THF dehydration tower 3 for purification. These three components are conventional equipment for BDO tar treatment in existing technologies. The difference lies in the structural improvement of the BDO light-weight removal tower 1 in existing technologies, which results in higher purity tetrahydrofuran output, facilitating the purification of polymer-grade tetrahydrofuran with a purity of over 99% through the THF dehydration tower 3.

[0041] According to the appendix Figure 2 As shown, a feed pipe 4 is fixed to the side of the BDO light removal tower 1, through which BDO tar is continuously fed into the BDO light removal tower 1. A condenser pipe 5 is connected to the side of the top of the BDO light removal tower 1. The BDO tar is heated and light removed inside the BDO light removal tower 1, and the evaporated gas is discharged from the BDO light removal tower 1 through the condenser pipe 5.

[0042] A distillation tank 6 is fixedly connected to the end of the condenser 5 away from the side wall of the BDO light content removal tower 1. The evaporated mixed gas exchanges heat with the material input in the feed pipe 4 through the condenser 5. The medium in the condenser 5 cools down and condenses, and is stored in the distillation tank 6 in stages. In the distillation tank 6, the condensed liquid is heated and distilled in multiple temperature ranges. Through multi-stage distillation, substances with different boiling points are extracted, thereby reducing the content of impurities in the extracted tetrahydrofuran.

[0043] The remaining liquid after distillation is fed back into feed pipe 4 for dilution. This not only allows for the recovery and utilization of waste heat from the equipment, but also prevents the diluted BDO tar from caking after heating, thus avoiding pollution to the environment caused by the direct discharge of condensate extracted from the BDO tar.

[0044] According to the appendix Figure 2 and attached Figure 3 As shown, a heat exchange box 9 is fixedly connected to the side wall of the BDO light-light removal tower 1. The heat exchange box 9 forms a protective barrier for the high-temperature structure outside the BDO light-light removal tower 1, avoiding burns caused by contact. At the same time, it is beneficial to make full use of the waste heat of the reaction to preheat the input materials.

[0045] The tar discharge pump 8 extends into the heat exchange box 9 to reheat the material input into the feed pipe 4 and the condensate returning from the distillation tank 6. This not only allows the hot tar discharged by the tar discharge pump 8 to distill the condensate returning from each distillation tank 6 at different temperature ranges, but also facilitates the recovery and utilization of waste heat from the equipment.

[0046] The baffle 7 is inclined and fixed to the inner wall of the bottom of the BDO light removal tower 1 to block the tar discharge pump 8, so as to prevent the material input into the BDO light removal tower 1 through the feed pipe 4 from being directly discharged through the tar discharge pump 8.

[0047] A heating plate 10 is provided inside the partition 7. The material blocked by the partition 7 is heated to the light removal temperature by the heating plate 10 and flows along the partition 7 until it is discharged in an orderly manner through the tar discharge pump 8. The tar discharge pump 8 is arranged in parallel with the distillation tank 6, and the material conveying direction in the tar discharge pump 8 is opposite to the distillation temperature sequence of the distillation tank 6. At the same time, the heat medium in the tar discharge pump 8 is used to preheat the feed pipe 4 and control the distillation temperature of the distillation tank 6.

[0048] According to the appendix Figure 4 As shown, the tar discharge pump 8 and the condenser tube 5 convey materials in the same direction, and a heat exchange plate 11 is fixedly connected to the side of the tar discharge pump 8 close to the lower surface of the distillation tank 6. The heat medium in the tar discharge pump 8 enters the heat exchange plate 11 and provides the heat energy required for distillation to the distillation tank 6 above the heat exchange plate 11. Under the heating action of the heat exchange plate 11, the specific components in the condensate in the distillation tank 6 evaporate again and continue to be transported along the condenser tube 5.

[0049] Multiple condenser tubes 5 are sequentially and inclinedly connected between adjacent distillation tanks 6. Multiple distillation tanks 6 are connected in series through condenser tubes 5 to form a distillation system for different evaporation temperature media in BDO tar. The purification of the output substance is achieved through distillation in multiple temperature ranges.

[0050] The material conveying directions of the feed pipe 4 and the condenser pipe 5 are opposite, which is conducive to making full use of the cold medium in the feed pipe 4 to cool and condense the condenser pipe 5.

[0051] A heat exchange tube 12 is fixedly connected to the middle section of the feed pipe 4 corresponding to the condenser pipe 5. The heat exchange tube 12 extends to the condenser pipe 5 and the tar discharge pump 8 and is set parallel to the condenser pipe 5. The feed pipe 4 extends to a position close to the condenser pipe 5 through the heat exchange tube 12, which is conducive to better condensation effect.

[0052] The liquid remaining after distillation in the distillation tank 6 is mainly composed of liquid water. This liquid is introduced into the starting end of the feed pipe 4, where a stirrer 13 is installed. The stirrer 13 mixes the BDO tar and liquid water, which on the one hand increases the water content of the BDO tar to avoid the decrease in fluidity after heating and removing light weights, thus affecting the continuous operation of the equipment. On the other hand, it can also effectively utilize the waste heat of the equipment to preheat the material, and at the same time avoids the direct discharge of the distillation liquid, which would cause pollution to the environment.

[0053] According to the appendix Figure 5 As shown, multiple distillation tanks 6 are connected in sequence by reflux pipes 14, and pressure valves 15 are provided on the side of the reflux pipes 14. When the liquid in the distillation tank 6 accumulates to a certain amount, the pressure valve 15 breaks through the set threshold and opens the reflux pipe 14. The liquid in the distillation tank 6 that cannot be evaporated by distillation enters the next distillation tank 6. This not only allows for the distillation of components again, but also removes liquid water with increasingly higher purity from the system.

[0054] The top of the furthest distillation tank 6 connected to the BDO light removal tower 1 is connected by a discharge pipe 16. This distillation tank 6 is connected to the THF dehydration tower 3 through the discharge pipe 16. The distillation temperature of the distillation tank 6 connected to the THF dehydration tower 3 through the discharge pipe 16 is most suitable for the evaporation of tetrahydrofuran. Combined with other components distilled in other distillation tanks 6, the tetrahydrofuran extracted at this location has higher purity and is more convenient to be directly purified into polymer-grade tetrahydrofuran with a purity of over 99% through the subsequent THF dehydration tower 3.

[0055] The bottom of the nearest distillation tank 6 connected to the BDO light removal tower 1 is connected to an outlet pipe 17. The distillation tank 6 is connected to the beginning of the feed pipe 4 through the outlet pipe 17. After the water in the system accumulates to a certain volume, the liquid water is discharged through the outlet pipe 17 and used to dilute the BDO tar introduced into the equipment, so as to realize the continuous use of the distillation equipment.

[0056] The method of using the equipment for preparing polymer-grade tetrahydrofuran from residues, and the preparation process are as follows:

[0057] S1. BDO tar is fed into BDO light tar removal tower 1 through feed pipe 4. BDO tar is heated in BDO light tar removal tower 1. THF, methanol, butanol and ethanol in BDO tar absorb heat and evaporate. The evaporated mixed gas is output from BDO light tar removal tower 1 through condenser pipe 5.

[0058] S2. The mixed gas output through the condenser 5 exchanges heat with the tar in the feed pipe 4. The mixed gas cools down and adheres to the inner wall of the condenser 5 to condense. The condensed liquid enters the distillation tank 6 along the condenser 5.

[0059] S3. The condensate in each distillation tank 6 is heated and distilled at different temperature ranges. Different components are separated sequentially under distillation at different temperature ranges and transported to specific areas along the pipeline. Finally, the remaining liquid is introduced into the starting end of the feed pipe 4 to dilute the input tar.

[0060] The equipment and method for preparing polymer-grade tetrahydrofuran from the residue are improved by modifying the structure of the existing BDO light removal tower 1. Multiple distillation tanks 6 are connected by condenser pipes 5. The heat energy of the tar discharge pump 8 is used for multi-stage heating and distillation in multiple temperature ranges. Different components are purified according to the boiling point of each impurity component. By finely controlling the distillation temperature, the tetrahydrofuran prepared from the residue contains fewer impurities, which can be easily passed into the THF dehydration tower 3 for direct purification into polymer-grade tetrahydrofuran with a purity of over 99%.

[0061] Furthermore, a baffle 7 is fixed at the bottom of the BDO light removal tower 1 to separate the feed pipe 4 from the tar discharge pump 8, so as to prevent the tar introduced into the BDO light removal tower 1 from being discharged directly without heating, and to slow down the tar introduced into the BDO light removal tower 1, so that the tar can be heated to the light removal temperature by the heating plate 10 and discharged outward in an orderly manner.

[0062] Furthermore, multiple distillation tanks 6 are connected in series via multi-section condenser tubes 5. The mixed gas discharged through the condenser tubes 5 exchanges heat with the material in the feed pipe 4 and condenses, then flows back to the distillation tanks 6 at different levels. The condensate in the different distillation tanks 6 is then heated and distilled at different temperature ranges by the tar discharge pump 8. Different components are distilled out according to their boiling points and discharged from the equipment to obtain tetrahydrofuran with high purity.

[0063] Furthermore, the remaining distillation liquid is introduced into the starting end of the feed pipe 4 through the outlet pipe 17, and a stirrer 13 is set at the starting end of the feed pipe 4. The remaining liquid is used to stir and dilute the tar introduced into the system. On the one hand, the waste heat is fully utilized to preheat the tar, and on the other hand, the components in the tar are prevented from being discharged and causing environmental pollution. At the same time, the diluted tar is heated and delighted, making it less likely to clump and affect the operation of the equipment.

[0064] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An apparatus for preparing polymerization-grade tetrahydrofuran from residue, comprising a BDO lightness removal tower (1), a BDO reactor (2) connected to the BDO lightness removal tower (1), and a THF dehydration tower (3) connected to the BDO lightness removal tower (1), characterized in that: A feed pipe (4) is fixed to the side of the BDO light removal tower (1), a condenser (5) is connected to the side of the top of the BDO light removal tower (1), and one end of the condenser (5) away from the side wall of the BDO light removal tower (1) is fixedly connected to a distillation tank (6). BDO tar is heated and light removed in the BDO light removal tower (1), and the evaporated mixed gas exchanges heat with the input material through the condenser (5). The medium in the condenser (5) is cooled and condensed and stored in the distillation tank (6) in sections. The condensed liquid is heated and distilled in multiple temperature ranges in the distillation tank (6), and the remaining liquid after distillation is returned to the feed pipe (4) to dilute the feed.

2. The equipment for preparing polymerization-grade tetrahydrofuran from residue as claimed in claim 1, characterized in that: A partition (7) is fixedly connected to the inner bottom of the BDO light removal tower (1), the feed pipe (4) is connected to the top of the partition (7), and a tar outlet pump (8) is fixedly connected to the side of the BDO light removal tower (1) and below the partition (7), and the tar outlet pump (8) is connected to the BDO reactor (2).

3. The equipment for preparing polymerization-grade tetrahydrofuran from residue as claimed in claim 2, characterized in that: A heat exchange box (9) is fixedly connected to the side wall of the BDO light removal tower (1). The tar outlet pump (8) extends into the heat exchange box (9) to reheat the material input from the feed pipe (4) and the condensed liquid refluxed in the distillation tank (6). The heat exchange box (9) is provided outside the BDO light removal tower (1) to protect the high-temperature structure.

4. The equipment for preparing polymerization-grade tetrahydrofuran from residue as claimed in claim 2, characterized in that: The partition (7) is tilted and fixed on the inner wall of the bottom of the BDO light removal tower (1) to form a shield for the tar outlet pump (8), and a heating plate (10) is arranged inside the partition (7). The tar outlet pump (8) is arranged in parallel with the distillation tank (6).

5. The equipment for preparing polymerization-grade tetrahydrofuran from residue as claimed in claim 2, characterized in that: The tar outlet pump (8) and the condenser (5) have the same material conveying direction, and the side of the tar outlet pump (8) is closely attached to the lower surface of the distillation tank (6) and fixedly connected to a heat exchange plate (11).

6. The equipment for preparing polymerization-grade tetrahydrofuran from residue as claimed in claim 1, characterized in that: Multiple sections of the condenser (5) are connected in sequence and tilted between adjacent distillation tanks (6); the multiple distillation tanks (6) are connected in series through the condenser (5); the material conveying directions of the feed pipe (4) and the condenser (5) are opposite; a heat exchange pipe (12) is fixedly connected to the middle section of the feed pipe (4) corresponding to the condenser (5); the heat exchange pipe (12) extends to the condenser (5) and the tar outlet pump (8) and is arranged parallel to the condenser (5); and a stirring member (13) is arranged at the starting end of the feed pipe (4).

7. The equipment for preparing polymer-grade tetrahydrofuran from residue as claimed in claim 1, characterized in that: A reflux pipe (14) is sequentially connected between the plurality of groups of distillation tanks (6), and a pressure valve (15) is arranged on the side of the reflux pipe (14).

8. The equipment for preparing polymerization-grade tetrahydrofuran from residue as claimed in claim 1, characterized in that: A discharge pipe (16) is connected through the top of the farthest distillation tank (6) connected to the BDO light removal tower (1), and the distillation tank (6) is connected to the THF dehydration tower (3) through the discharge pipe (16).

9. The equipment for preparing polymerization-grade tetrahydrofuran from residue as claimed in claim 1, characterized in that: A discharge pipe (17) is connected through the bottom of the distillation tank (6) closest to the BDO light removal tower (1), and the distillation tank (6) is connected to the starting end of the feed pipe (4) through the discharge pipe (17).

10. A method for using the equipment for preparing polymer-grade tetrahydrofuran from the residue according to any one of claims 1 to 9, characterized in that: The preparation process is as follows: S1, BDO tar is transported into the BDO light removal tower (1) through the feed pipe (4), the BDO tar enters the BDO light removal tower (1) and is heated, and components such as THF, methanol, butanol and ethanol in the BDO tar absorb heat and evaporate, and the evaporated mixed gas is output from the BDO light removal tower (1) through the condenser (5); S2, the mixed gas output through the condenser (5) exchanges heat with the tar in the feed pipe (4), the mixed gas cools down and adheres to the inner wall of the condenser (5) to condense, and the condensed liquid flows along the condenser (5) into the distillation tank (6); S3, the condensed liquid in each distillation tank (6) is heated and distilled in different temperature sections, and different components are separated in sequence under the distillation in different temperature ranges and transported to a specific area along the pipeline. Finally, the remaining liquid is introduced into the starting end of the feed pipe (4) to dilute the input tar.

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