Emission reduction system for producing tetrahydrofuran from 1, 4-butanediol

Abstract

The utility model provides an emission reduction system for producing tetrahydrofuran from 1, 4-butanediol, and relates to the technical field of chemical production equipment. By arranging the 1, 4-butanediol raffinate separation unit, the 1, 4-butanediol raffinate generated in the tetrahydrofuran production unit can directly enter the film evaporator to be separated, the light component 1, 4-butanediol is rapidly evaporated and flows out from the first gas phase outlet, and the light component 1, 4-butanediol is condensed by the gas phase condenser and then returns to the tetrahydrofuran production unit to serve as a raw material to be recycled. And heavy components of tar in the film evaporator flow out from a first liquid phase outlet at the bottom and are discharged and incinerated. The system can further separate the 1, 4-butanediol raffinate generated in the tetrahydrofuran production unit, and recycle the 1, 4-butanediol in the raffinate, so that the material waste of the 1, 4-butanediol is reduced, and the utilization rate of the 1, 4-butanediol raw material is improved. And meanwhile, the 1, 4-butanediol residual liquid discharge incineration treatment amount is greatly reduced, energy conservation and emission reduction are achieved, and the production cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical production equipment, and particularly relates to an emission reduction system for producing tetrahydrofuran from 1,4-butanediol. Background Technique

[0002] 1,4-Butanediol (BDO) is an important organic chemical and fine chemical raw material, which is mainly used for producing tetrahydrofuran (THF), γ-butyrolactone (GBL), polyurethane and thermoplastic engineering plastic PBT resin, etc. In addition, 1,4-butanediol can also be used to prepare N-methylpyrrolidone, N-vinylpyrrolidone and other pyrrolidone derivatives, and is also used to prepare vitamin B6, pesticides, herbicides, and as solvents, plasticizers, lubricants, humectants, softeners, adhesives and brighteners for electroplating industry in various technological processes.

[0003] At present, in the process of producing tetrahydrofuran from 1,4-butanediol, generally under an acidic catalyst, 1,4-butanediol is dehydrated and cyclized to produce tetrahydrofuran, and the obtained tetrahydrofuran can be further used as a monomer for producing polytetrahydrofuran. However, during the process of producing tetrahydrofuran by dehydrating and cyclizing 1,4-butanediol, a small amount of tar is by-produced. Since it is difficult to separate the tar from the unreacted 1,4-butanediol raw material, it is generally directly discharged and incinerated as residual liquid. Therefore, problems such as low utilization rate of 1,4-butanediol raw material, material waste, large amount of residual liquid discharge treatment, and high treatment cost are caused.

[0004] In view of this, the present utility model is specifically proposed. Summary of the Utility Model

[0005] The purpose of the present utility model is to provide an emission reduction system for producing tetrahydrofuran from 1,4-butanediol, which can recover 1,4-butanediol in the residual liquid of producing tetrahydrofuran from 1,4-butanediol, realize the recycling of 1,4-butanediol, and reduce the amount of residual liquid discharge treatment.

[0006] The embodiments of the present utility model are implemented as follows:

[0007] In a first aspect, the present utility model provides an emission reduction system for producing tetrahydrofuran from 1,4-butanediol, including a tetrahydrofuran production unit and a 1,4-butanediol residual liquid separation unit.

[0008] The 1,4 - butanediol residue separation unit includes a thin - film evaporator, a gas - phase condenser, and a 1,4 - butanediol storage tank. The thin - film evaporator includes a raw material inlet, a first gas - phase outlet, and a first liquid - phase outlet. The first gas - phase outlet is located at the top of the thin - film evaporator, and the first liquid - phase outlet is located at the bottom of the thin - film evaporator. The raw material inlet is connected to the tetrahydrofuran production unit through a pipeline. The first gas - phase outlet is connected to the gas - phase condenser through a pipeline. The gas - phase condenser is connected to the inlet of the 1,4 - butanediol storage tank through a pipeline. The outlet of the 1,4 - butanediol storage tank is connected to the tetrahydrofuran production unit through a pipeline. The first liquid - phase outlet is connected to an external incineration device through a pipeline.

[0009] Optionally, it further includes a heat - transfer oil storage tank. The thin - film evaporator is also provided with a housing, and a heat - transfer oil inlet and a heat - transfer oil outlet are further provided on the housing. Both the heat - transfer oil inlet and the heat - transfer oil outlet are connected to the heat - transfer oil storage tank.

[0010] Optionally, the heat - transfer oil inlet is located at the lower end of the housing of the thin - film evaporator, the heat - transfer oil outlet is located at the upper end of the housing of the thin - film evaporator, and the heat - transfer oil outlet is lower than the raw material inlet.

[0011] Optionally, a liquid - phase reflux port is further provided on the thin - film evaporator. The liquid - phase reflux port is connected to the first liquid - phase outlet through a pipeline, and a liquid - phase circulation pump is further provided on the pipeline connecting the liquid - phase reflux port and the first liquid - phase outlet.

[0012] Optionally, the liquid - phase reflux port is located near the top of the thin - film evaporator and is at the same horizontal position as the raw material inlet.

[0013] Optionally, the gas - phase condenser includes a second gas - phase outlet and a second liquid - phase outlet. The second liquid - phase outlet is connected to the inlet of the 1,4 - butanediol storage tank through a pipeline, and the second gas - phase outlet is connected to an external incineration device through a pipeline.

[0014] Optionally, a vacuum pump is further provided on the pipeline connecting the second gas - phase outlet and the external incineration device.

[0015] Optionally, a delivery pump is further provided on the pipeline connecting the outlet of the 1,4 - butanediol storage tank and the tetrahydrofuran production unit.

[0016] Optionally, a demister is provided at the top of the thin - film evaporator.

[0017] The beneficial effects of the embodiments of the present utility model are:

[0018] The utility model provides an emission reduction system for producing tetrahydrofuran from 1,4-butanediol. By setting up a 1,4-butanediol residue separation unit, the 1,4-butanediol residue generated in the tetrahydrofuran production unit can directly enter the thin-film evaporator for separation. The light component, 1,4-butanediol, is quickly evaporated and flows out from the first gas-phase outlet. After being converted into a liquid phase through a gas-phase condenser, it flows into the 1,4-butanediol storage tank, and then the 1,4-butanediol returns to the tetrahydrofuran production unit for recycling as a raw material. The tar heavy components in the thin-film evaporator flow out from the first liquid-phase outlet at the bottom for external discharge and incineration treatment. This system can further separate the 1,4-butanediol residue containing components such as tar and unreacted 1,4-butanediol generated in the tetrahydrofuran production unit, recycle the 1,4-butanediol therein, and the recovery rate of 1,4-butanediol is ≥75%. It reduces the material waste of 1,4-butanediol and improves the utilization rate of 1,4-butanediol raw materials. At the same time, it greatly reduces the amount of 1,4-butanediol residue for external discharge and incineration treatment, and the incineration treatment rate of 1,4-butanediol residue is reduced to less than 25%, achieving energy conservation and emission reduction and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present utility model, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a schematic structural diagram of the emission reduction system for producing tetrahydrofuran from 1,4-butanediol provided by the embodiment of the present utility model;

[0021] Figure 2 It is a schematic structural diagram of the 1,4-butanediol residue separation unit provided by the embodiment of the present utility model.

[0022] Reference numerals: 100 - Emission reduction system for producing tetrahydrofuran from 1,4-butanediol; 110 - Tetrahydrofuran production unit; 120 - 1,4-butanediol residue separation unit; 121 - Thin-film evaporator; 1211 - Raw material inlet; 1212 - First gas-phase outlet; 1213 - First liquid-phase outlet; 1214 - Heat transfer oil inlet; 1215 - Heat transfer oil outlet; 1216 - Liquid-phase reflux port; 122 - Gas-phase condenser; 1221 - Second gas-phase outlet; 1222 - Second liquid-phase outlet; 123 - 1,4-butanediol storage tank; 124 - Heat transfer oil storage tank; 125 - Liquid-phase circulation pump; 126 - Delivery pump; 127 - Demister; 128 - Vacuum pump; 200 - Incineration device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of them. The components of the embodiments of the present utility model usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present utility model provided in the accompanying drawings is not intended to limit the scope of the claimed present utility model, but merely represents selected embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts fall within the scope of protection of the present utility model.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0026] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the utility model product is usually placed during use. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0027] In addition, terms such as "horizontal" and "vertical" do not mean that the components are required to be absolutely horizontal or hanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0028] In the description of the present utility model, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0029] 1,4-butanediol in the present utility model is an important organic chemical raw material. In industry, 1,4-butanediol is used to produce tetrahydrofuran through dehydration cyclization, and tetrahydrofuran is a key raw material for producing polytetrahydrofuran. In the existing production process of tetrahydrofuran, the residual liquid containing components such as 1,4-butanediol and heavy oil by-products obtained from the reaction is usually directly discharged and incinerated, which causes problems such as waste of 1,4-butanediol materials, large amount of residual liquid discharge treatment, and high treatment cost. Therefore, the embodiment of the present utility model provides a system for separating the 1,4-butanediol residual liquid obtained from the above reaction unit in the system for producing tetrahydrofuran from 1,4-butanediol, recycling 1,4-butanediol, reducing waste of 1,4-butanediol materials, and at the same time reducing the amount of residual liquid discharged for treatment, as follows.

[0030] Please refer to Figure 1 , this embodiment provides an emission reduction system 100 for producing tetrahydrofuran from 1,4-butanediol, which includes a tetrahydrofuran production unit 110 and a 1,4-butanediol residual liquid separation unit 120.

[0031] Among them, the tetrahydrofuran production unit 110 can adopt an existing tetrahydrofuran production system, as long as it is a system for preparing tetrahydrofuran by dehydration cyclization of 1,4-butanediol. For example, a key cyclization reactor is provided in this system. 1,4-butanediol contacts with an acidic catalyst in the cyclization reactor to undergo dehydration cyclization reaction to generate tetrahydrofuran. The obtained tetrahydrofuran product is led out of the cyclization reactor through a pipeline, and then through separation, a tetrahydrofuran product and a residual liquid containing unreacted 1,4-butanediol, by-product tar, a small amount of tetrahydrofuran and other components are obtained. This residual liquid is the 1,4-butanediol residual liquid in the embodiment of the present utility model.

[0032] The 1,4-butanediol residual liquid separation unit 120 is used to separate the above 1,4-butanediol residual liquid, mainly to separate 1,4-butanediol from tar, and recycle the separated 1,4-butanediol back to the tetrahydrofuran production unit 110 for recycling, which not only reduces waste of 1,4-butanediol materials, but also greatly reduces the amount of 1,4-butanediol residual liquid discharged for treatment.

[0033] Please refer to Figure 2, 1,4 - butanediol residue separation unit 120 includes a thin - film evaporator 121, a gas - phase condenser 122 and a 1,4 - butanediol storage tank 123. The separation principle of the 1,4 - butanediol residue separation unit 120 is as follows: The 1,4 - butanediol residue from the tetrahydrofuran production unit 110 enters the thin - film evaporator 121 through the raw material inlet 1211 of the thin - film evaporator 121. The 1,4 - butanediol residue flows in a thin - film shape along the heating tube wall in the thin - film evaporator 121 for heat transfer and evaporation. The 1,4 - butanediol residue has a large vaporization surface area, enabling the liquid film of the 1,4 - butanediol residue to flow rapidly over the heating surface. In the high - temperature environment in the thin - film evaporator 121, light components such as 1,4 - butanediol and tetrahydrofuran in the 1,4 - butanediol residue are quickly evaporated and discharged from the top. Therefore, the first gas - phase outlet 1212 for discharging the 1,4 - butanediol light components of the thin - film evaporator 121 is located at the top of the thin - film evaporator 121. The remaining tar heavy components in the 1,4 - butanediol residue gather at the bottom along the thin - film evaporator 121. Therefore, the first liquid - phase outlet 1213 for discharging the tar heavy components of the thin - film evaporator 121 is located at the bottom of the thin - film evaporator 121, and the tar heavy - component liquid phase is discharged for incineration treatment.

[0034] The 1,4 - butanediol discharged from the top of the thin - film evaporator 121 enters the gas - phase condenser 122 through a pipeline, is condensed in the gas - phase condenser 122, and the 1,4 - butanediol in the gas is condensed from the gas phase to the liquid phase, and then enters the 1,4 - butanediol storage tank 123 through a pipeline, and is then transported to the tetrahydrofuran production unit 110 through a pipeline for recycling.

[0035] Therefore, in the 1,4 - butanediol residue separation unit 120 of the embodiment of the present utility model, the thin - film evaporator 121 includes a raw material inlet 1211, a first gas - phase outlet 1212 and a first liquid - phase outlet 1213. The first gas - phase outlet 1212 is located at the top of the thin - film evaporator 121, and the first liquid - phase outlet 1213 is located at the bottom of the thin - film evaporator 121; the raw material inlet 1211 is connected to the tetrahydrofuran production unit 110 through a pipeline, the first gas - phase outlet 1212 is connected to the gas - phase condenser 122 through a pipeline, the second liquid - phase outlet 1222 of the gas - phase condenser 122 is connected to the inlet of the 1,4 - butanediol storage tank 123 through a pipeline, the outlet of the 1,4 - butanediol storage tank 123 is connected to the tetrahydrofuran production unit 110 through a pipeline, and the first liquid - phase outlet 1213 is connected to an external incineration device 200 through a pipeline.

[0036] In this embodiment, in order to improve the separation effect of 1,4-butanediol and tar in the thin-film evaporator 121, the 1,4-butanediol residue separation unit 120 further includes a heat transfer oil storage tank 124. The thin-film evaporator 121 is also provided with a housing, and a heat transfer oil inlet 1214 and a heat transfer oil outlet 1215 are further provided on the housing. Both the heat transfer oil inlet 1214 and the heat transfer oil outlet 1215 are communicated with the heat transfer oil storage tank 124.

[0037] The heat transfer oil storage tank 124 stores heat transfer oil, and the heat transfer oil is used to provide heat inside the thin-film evaporator 121, so that the light components of 1,4-butanediol in the thin-film evaporator 121 can be quickly evaporated.

[0038] In this embodiment, the thin-film evaporator 121 is of a vertical structure and has a top and a bottom. The heating inner wall surface of the thin-film evaporator 121 is also of a vertical structure. Therefore, in order to improve the separation effect of the light components of 1,4-butanediol and the heavy components of tar in the thin-film evaporator 121, the raw material inlet 1211 of the thin-film evaporator 121 should be located at one end of the thin-film evaporator 121 close to the top, so as to ensure that during the process of the 1,4-butanediol residue flowing downward under gravity, it can contact the heating inner wall surface in the thin-film evaporator 121 as much as possible, and ensure that as much 1,4-butanediol in the 1,4-butanediol residue is vaporized.

[0039] Furthermore, since the thin-film evaporator 121 in this embodiment is of a vertical structure, therefore, the heat transfer oil inlet 1214 and the heat transfer oil outlet 1215 should also be respectively distributed at the lower end and the upper end of the housing of the thin-film evaporator 121 to ensure that the heat transfer oil can better provide heat for the thin-film evaporator 121.

[0040] In this embodiment, the heat transfer oil inlet 1214 is located near the lower end of the housing of the thin-film evaporator 121, the heat transfer oil outlet 1215 is located at the upper end of the housing of the thin-film evaporator 121, and the heat transfer oil outlet 1215 is lower than the raw material inlet 1211.

[0041] In this embodiment, in order to reduce the content of 1,4-butanediol in the heavy components of tar flowing out from the first liquid phase outlet 1213 at the bottom and obtain heavy components of tar with higher purity, a liquid phase reflux port 1216 is further provided on the thin-film evaporator 121. The liquid phase reflux port 1216 is communicated with the first liquid phase outlet 1213 through a pipeline, and a liquid phase circulation pump 125 is also provided on the pipeline connecting the liquid phase reflux port 1216 and the first liquid phase outlet 1213. Therefore, the heavy components of tar flowing out from the first liquid phase outlet 1213 are circulated and separated in the thin-film evaporator 121 multiple times through the liquid phase reflux port 1216 to reduce the content of 1,4-butanediol in the heavy components of tar.

[0042] In this embodiment, in order to enhance mass and heat transfer, the liquid phase reflux port 1216 is located at one end near the top of the thin-film evaporator 121 and is at the same horizontal position as the raw material inlet 1211.

[0043] The function of the gas-phase condenser 122 is to condense the light components flowing out from the top of the thin-film evaporator 121 into the liquid phase, thereby collecting 1,4-butanediol.

[0044] Therefore, in this embodiment, the gas-phase condenser 122 includes a second gas-phase outlet 1221 and a second liquid-phase outlet 1222. The second liquid-phase outlet 1222 is connected to the inlet of the 1,4-butanediol storage tank 123 through a pipeline for collecting and temporarily storing the 1,4-butanediol obtained by condensation. The second gas-phase outlet 1221 is connected to an external incineration device 200 through a pipeline for treating the non-condensable gas light components flowing out from the top of the thin-film evaporator 121.

[0045] It can be understood that the temperature of the refrigerant medium of the gas-phase condenser 122 is set to be the temperature capable of condensing 1,4-butanediol from the gas phase to the liquid phase.

[0046] In this embodiment, a vacuum pump 128 is further provided on the pipeline connecting the second gas-phase outlet 1221 and the external incineration device 200, which is used to provide a high-vacuum environment for the thin-film evaporator 121, improve the separation effect of 1,4-butanediol and tar, and save energy and reduce consumption.

[0047] In this embodiment, a transfer pump 126 is further provided on the pipeline connecting the outlet of the 1,4-butanediol storage tank 123 and the tetrahydrofuran production unit 110, which is convenient for pumping the 1,4-butanediol in the 1,4-butanediol storage tank 123 into the tetrahydrofuran production unit 110 to be recycled as a reaction raw material for tetrahydrofuran and improve the utilization rate of 1,4-butanediol.

[0048] In this embodiment, a demister 127 is provided at the top of the thin-film evaporator 121, which is used to capture the liquid droplets or foams entrained by the top light components and make them fall back onto the heated inner wall of the thin-film evaporator 121.

[0049] The working principle of an emission reduction system 100 for producing tetrahydrofuran from 1,4-butanediol provided by an embodiment of the present utility model is as follows:

[0050] 1) The tetrahydrofuran production unit 110 uses 1,4-butanediol as a raw material and obtains tetrahydrofuran products through dehydration cyclization under an acidic catalyst. The tetrahydrofuran products are separated to obtain tetrahydrofuran products and residual liquid. This residual liquid is the 1,4-butanediol residual liquid, which mainly includes unreacted 1,4-butanediol, by-product tar, a small amount of tetrahydrofuran and other components. The above-mentioned 1,4-butanediol residual liquid is sent into the 1,4-butanediol residual liquid separation unit 120 through a pipeline for separating 1,4-butanediol and other components.

[0051] 2) Feed the heat transfer oil in the heat transfer oil storage tank 124 into the shell of the thin film evaporator 121 to ensure that the inside of the thin film evaporator 121 is in a heating state. And evacuate the air through the vacuum pump 128 to maintain a vacuum state inside the thin film evaporator 121. Then, the 1,4-butanediol residue from the tetrahydrofuran production unit 110 enters the thin film evaporator 121. The 1,4-butanediol residue forms a centrifugal force through high-speed rotation in the thin film evaporator 121, dispersing the liquid into a uniform thin film and distributing it on the heated inner wall of the thin film evaporator 121. The light components of 1,4-butanediol are evaporated to form a gas phase, and are extracted from the top of the thin film evaporator 121 through the vacuum pump 128. A demister 127 is provided at the upper part of the thin film evaporator 121 to capture the liquid droplets or foam entrained in the gas phase and make them fall back onto the heated inner wall of the thin film evaporator 121. The remaining tar heavy components gather at the bottom due to gravity, are discharged from the first liquid phase outlet 1213 and pumped back into the thin film evaporator 121 through the liquid phase circulation pump 125 for circulating treatment to separate more 1,4-butanediol. After multiple cycles of extraction, the tar heavy components are discharged from the first liquid phase outlet 1213 and directly sent to the external incineration device 200 for incineration.

[0052] 3) The gas phase collected at the top of the thin film evaporator 121 enters the gas phase condenser 122 through a pipeline. After being cooled by the gas phase condenser 122, the high-temperature gaseous 1,4-butanediol is condensed into a liquid state, and then the liquid 1,4-butanediol flows into the 1,4-butanediol storage tank 123 through a pipeline for collection and temporary storage. The non-condensable gas light components in the gas phase condenser 122 are extracted from the second gas phase outlet 1221 through the vacuum pump 128 and enter the external incineration device 200 for incineration.

[0053] 4) The 1,4-butanediol temporarily stored in the 1,4-butanediol storage tank 123 is transported to the tetrahydrofuran production unit 110 through the transfer pump 126 and can be recycled as a raw material for producing tetrahydrofuran.

[0054] This system can recycle the 1,4-butanediol residue generated by the tetrahydrofuran production unit 110, reduce the waste of 1,4-butanediol, improve the utilization rate of 1,4-butanediol, and reduce the incineration treatment cost of the 1,4-butanediol residue. Moreover, the recovery rate of the 1,4-butanediol separated and recycled by this system is ≥75%, and the incineration treatment rate of the 1,4-butanediol residue is reduced to less than 25%. It can improve the device production capacity, reduce the discharge of three wastes, and has important significance and economic benefits for the industrial production process of polytetrahydrofuran.

[0055] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, various modifications and variations can be made to the present utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An emission reduction system for producing tetrahydrofuran from 1,4-butanediol, characterized in that, It includes a tetrahydrofuran production unit and a 1,4-butanediol residue separation unit; The 1,4-butanediol residue separation unit includes a thin-film evaporator, a gas-phase condenser and a 1,4-butanediol storage tank. The thin-film evaporator includes a raw material inlet, a first gas-phase outlet and a first liquid-phase outlet. The first gas-phase outlet is located at the top of the thin-film evaporator, and the first liquid-phase outlet is located at the bottom of the thin-film evaporator; the raw material inlet is connected to the tetrahydrofuran production unit through a pipeline, the first gas-phase outlet is connected to the gas-phase condenser through a pipeline, the gas-phase condenser is connected to the inlet of the 1,4-butanediol storage tank through a pipeline, the outlet of the 1,4-butanediol storage tank is connected to the tetrahydrofuran production unit through a pipeline, and the first liquid-phase outlet is connected to an external incineration device through a pipeline.

2. The system according to claim 1, characterized in that, It further includes a heat-conducting oil storage tank. The thin-film evaporator is also provided with a shell, and a heat-conducting oil inlet and a heat-conducting oil outlet are also arranged on the shell. Both the heat-conducting oil inlet and the heat-conducting oil outlet are connected to the heat-conducting oil storage tank.

3. The system according to claim 2, wherein The heat-conducting oil inlet is located at the lower end of the shell of the thin-film evaporator, the heat-conducting oil outlet is located at the upper end of the shell of the thin-film evaporator, and the heat-conducting oil outlet is lower than the raw material inlet.

4. The system according to claim 1, wherein A liquid-phase reflux port is also arranged on the thin-film evaporator. The liquid-phase reflux port is connected to the first liquid-phase outlet through a pipeline, and a liquid-phase circulation pump is also arranged on the pipeline connecting the liquid-phase reflux port and the first liquid-phase outlet.

5. The system according to claim 4, wherein The liquid-phase reflux port is located at one end near the top of the thin-film evaporator and is at the same horizontal position as the raw material inlet.

6. The system according to claim 1, wherein The gas-phase condenser includes a second gas-phase outlet and a second liquid-phase outlet. The second liquid-phase outlet is connected to the inlet of the 1,4-butanediol storage tank through a pipeline, and the second gas-phase outlet is connected to an external incineration device through a pipeline.

7. The system according to claim 6, wherein A vacuum pump is also arranged on the pipeline connecting the second gas-phase outlet and the external incineration device.

8. The system according to claim 1, characterized in that A delivery pump is also arranged on the pipeline connecting the outlet of the 1,4-butanediol storage tank and the tetrahydrofuran production unit.

9. The system according to claim 1, wherein A demister is arranged on the upper part of the end face at the top of the thin-film evaporator.

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