Method and device for recovering and separating waste liquid generated in gamma-butyrolactone production

Abstract

The invention relates to a method for recycling and separating waste liquid generated in gamma-butyrolactone production, which adopts pervaporation membrane separation and rectification separation to recycle waste liquid containing tetrahydrofuran, water, butanol and 1, 4-butyrolactone. The method specifically comprises the following steps: S1, feeding the waste liquid into a first rectifying tower 1, evaporating a gas-phase mixture from the tower top, and extracting a first tower kettle liquid from the tower kettle; s2, feeding the first tower bottoms into a second rectifying tower 2, and obtaining a crude product GBL from the top of the second rectifying tower; s3, carrying out membrane dehydration on the gas-phase mixture obtained at the top of the first rectifying tower 1, feeding a membrane finished product into a third rectifying tower 3, extracting a THF-containing gas-phase mixture from the top of the third rectifying tower, and obtaining an NBU-containing liquid-phase mixed solution at the tower kettle; s4, feeding an NBU-containing liquid-phase mixed solution obtained from the tower kettle of the third rectifying tower 3 into a fifth rectifying tower 5, and obtaining an NBU product from the tower top of the fifth rectifying tower; and S5, extracting a THF-containing gas-phase mixture from the top of the third rectifying tower, feeding the THF-containing gas-phase mixture into a fourth rectifying tower 4, and obtaining a THF product from the tower kettle of the fourth rectifying tower.

Description

Technical Field

[0001] The invention relates to the field of waste liquid recovery and separation, in particular to a method and device for recovering and separating waste liquid generated by producing gamma-butyrolactone. Background Art

[0002] γ-Butyrolactone (GBL) is an important organic synthesis raw material and excellent solvent, and its demand is growing. The existing production process of GBL is mainly produced by dehydrogenation of 1,4-butanediol (BDO). The waste liquid produced in the process contains many impurities, including tetrahydrofuran (THF), butanol (NBU), water and GBL. At present, the treatment of GBL by-product waste liquid is mostly extensive, using pressure swing distillation to recover part of THF, but the quality is not high, and other components will still form waste liquid. The recovery is not thorough, and it is difficult to achieve good economic value.

[0003] THF, NBU and water are partially miscible and form azeotropes, which makes separation difficult. Currently, there is no research on the separation of the THF-water-NBU-GBL quaternary system. Summary of the invention

[0004] The object of the present invention is to provide a method and device for recovering and separating waste liquid generated in the production of gamma-butyrolactone.

[0005] The technical solution to achieve the purpose of the present invention is:

[0006] A method for recovering and separating waste liquid generated by the production of gamma-butyrolactone; comprising the following steps:

[0007] S1, the waste liquid is put into the first distillation tower, the gas phase mixture is evaporated from the top of the tower, and the first bottom liquid is extracted from the bottom of the tower;

[0008] S2, the bottom liquid of the first tower is fed into the second distillation tower, and the crude GBL is obtained from the top of the second distillation tower;

[0009] S3, the gas phase mixture obtained at the top of the first distillation tower is dehydrated by a membrane and then enters the third distillation tower, the gas phase mixture containing THF is extracted from the top of the third distillation tower, and the liquid phase mixture containing NBU is obtained in the kettle of the third distillation tower;

[0010] S4, the NBU-containing liquid phase mixture obtained in the kettle of the third distillation tower is fed into the fifth distillation tower, and the NBU product is obtained from the top of the fifth distillation tower;

[0011] S5. The gas phase mixture containing THF is taken out from the top of the third distillation tower and fed into the fourth distillation tower, and the THF product is obtained from the bottom of the fourth distillation tower.

[0012] Furthermore, in the above method, the operating parameters of the first distillation tower are an absolute pressure of 30 KPa, a top temperature of 63°C, a bottom temperature of 179°C, and a reflux ratio of 3; the operating parameters of the second distillation tower are an absolute pressure of 5 KPa, a top temperature of 112.3°C, a bottom temperature of 177.9°C, and a reflux ratio of 3; the operating parameters of the third distillation tower are an absolute pressure of 110 KPa, a top temperature of 67.3°C, a bottom temperature of 125.8°C, and a reflux ratio of 5; the operating parameters of the fourth distillation tower are an absolute pressure of 100 KPa, a top temperature of 60.3°C, a bottom temperature of 72.2°C, and a reflux ratio of 21; the operating parameters of the fifth distillation tower are an absolute pressure of 100 KPa, a top temperature of 117.7°C, a bottom temperature of 155.2°C, and a reflux ratio of 1.6.

[0013] Furthermore, the theoretical plate numbers of the first distillation tower, the second distillation tower, the third distillation tower and the fifth distillation tower are all 20; the theoretical plate number of the fourth distillation tower is 35.

[0014] Furthermore, the waste liquid enters the first distillation tower from the tower, specifically from the top of the 10th tower plate; the waste liquid enters the second distillation tower through the tower, specifically from the top of the 10th tower plate; the waste liquid enters the third distillation tower through the tower, specifically from the top of the 10th tower plate; the waste liquid enters the fourth distillation tower through the tower, specifically from the top of the 30th tower plate; the waste liquid enters the fifth distillation tower through the tower, specifically from the top of the 10th tower plate.

[0015] The waste liquid generated by the production of γ-butyrolactone includes 17.802-35.604 wt.%, tetrahydrofuran, 12.864-25.728 wt.%, water, 10.572-21.144 wt.%, butanol, and 10.752-21.504 wt.% of 1,4-butyrolactone GBL.

[0016] Correspondingly, the present invention also provides a waste liquid recovery and separation device generated by the production of γ-butyrolactone, comprising a distillation component, a membrane component, a cooling component, and a tower top collection component, wherein: the distillation component comprises a first distillation tower, a second distillation tower, a third distillation tower, a fourth distillation tower, and a fifth distillation tower; the cooling component comprises a condenser, a reflux tank, and a pump; the tower top collection component comprises a tower top cooler and a distillate temporary storage tank;

[0017] The top of the first distillation tower is connected to the first cooling assembly, the first tower top collecting assembly, and the membrane assembly in sequence, the intercepting side of the membrane assembly is connected to the third distillation tower, and the kettle of the first distillation tower is connected to the second distillation tower; the top of the second distillation tower is connected to the second cooling assembly and the second tower top collecting assembly in sequence, and the second tower top collecting assembly extracts the crude GBL;

[0018] The top of the third distillation tower is connected in sequence to the third cooling assembly, the third tower top collecting assembly, and the fourth distillation tower, and the kettle of the third distillation tower is connected to the fifth distillation tower; the kettle of the fourth distillation tower produces THF product;

[0019] The top of the fifth distillation tower is connected to the fifth cooling assembly and the fifth tower top collecting assembly in sequence, and the NBU product is extracted through the fifth tower top collecting assembly.

[0020] Furthermore, in the above device, an evaporator and a superheater are provided after the first tower top collecting component; the first tower top collecting component is connected to the evaporator, the superheater, and the membrane component in sequence.

[0021] Furthermore, the top of the first distillation tower is connected to the first condenser, the outlet of the first condenser is connected to the first reflux tank, the first reflux tank is connected to the first pump, the outlet pipeline of the first pump is divided into two routes, one route enters the top of the first distillation tower, and the other route enters the first top cooler, the outlet of the first top cooler is connected to the first distillate temporary storage tank, the first distillate temporary storage tank is connected to the evaporator through the first transfer pump, the evaporator is connected to the superheater, the superheater is connected to the membrane module, the intercepting side of the membrane module is connected to the finished product condenser, the finished product condenser outlet is connected to the membrane finished product tank, the membrane finished product tank is connected to the transfer pump, and the transfer pump is connected to the third distillation tower;

[0022] The kettle of the first distillation tower is connected to the second distillation tower through the first kettle pump; the top of the second distillation tower is connected to the outlet of the second condenser connected to the second reflux tank, the second reflux tank is connected to the second pump, the outlet pipeline of the second pump is divided into two branches, one pipeline enters the top of the second distillation tower, and the other enters the second tower top cooler, the outlet of the second tower top cooler is connected to the second distillate temporary storage tank, the second distillate temporary storage tank is connected to the second material transfer pump, and the crude GBL product is produced;

[0023] The top of the third distillation tower is connected to the outlet of the third condenser, which is connected to the third reflux tank. The third reflux tank is connected to the third pump. The pipeline at the outlet of the third pump is divided into two branches, one of which enters the top of the third distillation tower, and the other enters the third top cooler. The outlet of the third top cooler is connected to the third distillate temporary storage tank, which is connected to the third distillate temporary storage tank and the third material transfer pump. The third material transfer pump is connected to the fourth distillation tower; the kettle of the third distillation tower is connected to the fifth distillation tower through the third kettle pump;

[0024] The top of the fourth distillation tower is connected to the outlet of the fourth condenser, which is connected to the fourth reflux tank. The fourth reflux tank is connected to the fourth pump. The pipeline at the outlet of the fourth pump is divided into two branches, one of which enters the top of the fourth distillation tower, and the other enters the fourth tower top cooler. The outlet of the fourth tower top cooler is connected to the fourth distillate temporary storage tank, which is connected to the fourth distillate temporary storage tank. The fourth material transfer pump extracts impurities; the fourth distillation tower kettle extracts THF product through the fourth tower kettle pump;

[0025] The top of the fifth distillation tower is connected to the outlet of the fifth condenser, which is connected to the fifth reflux tank. The fifth reflux tank is connected to the fifth pump. The pipeline at the outlet end of the fifth pump is divided into two branches. One pipeline enters the top of the fifth distillation tower, and the other enters the fifth top cooler. The outlet of the fifth top cooler is connected to the fifth distillate temporary storage tank, which is connected to the fifth distillate temporary storage tank and the fifth material transfer pump. The fifth material transfer pump produces NBU.

[0026] Compared with the prior art, the present invention has the following significant advantages: the method and device are used to recover tetrahydrofuran (THF), butanol (NBU) and GBL in waste liquid, and the product purity is high, meeting the standards for reuse or external sale; and the coupling of distillation and pervaporation membrane separation technology makes it easy to purify the product later without introducing a third component. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a process flow chart of the present invention.

[0028] In the figure, 1 the first distillation tower, 11 the first condenser, 12 the first reflux tank, 13 the first pump, 14 the first tower top cooler, 15 the first distillate temporary storage tank, 16 the first transfer pump, 17 the first tower bottom pump, 2 the second distillation tower, 21 the second condenser, 22 the second reflux tank, 23 the second pump, 24 the second tower top cooler, 25 the second distillate temporary storage tank, 26 the second transfer pump, 6 the membrane module, 61 the evaporator, 62 the superheater, 63 the finished product condenser, 64 the membrane finished product tank, 65 the transfer pump, 3 the third distillation tower, 31 the third condenser, 3 2 the third reflux tank, 33 the third pump, 34 the third tower top cooler, 35 the third distillate temporary storage tank, 36 the third material transfer pump, 37 the third tower bottom pump, 4 the fourth distillation tower, 41 the fourth condenser, 42 the fourth reflux tank, 43 the fourth pump, 44 the fourth tower top cooler, 45 the fourth distillate temporary storage tank, 46 the fourth material transfer pump, 47 the fourth tower bottom pump, 5 the fifth distillation tower, 51 the fifth condenser, 52 the fifth reflux tank, 53 the fifth pump, 54 the fifth tower top cooler, 55 the fifth distillate temporary storage tank, 56 the fifth material transfer pump, 57 the fifth tower bottom pump. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] The waste liquid produced by the production of γ-butyrolactone includes 17.802-35.604 wt.%, of tetrahydrofuran, 12.864-25.728 wt.%, of water, 10.572-21.144 wt.%, of butanol, and 10.752-21.504 wt.% of 1,4-butyrolactone GBL. As a specific embodiment, the waste liquid produced by the production of γ-butyrolactone includes 29.67 wt.%, of tetrahydrofuran, 21.44 wt.%, of water, 17.62 wt.%, of butanol, and 17.92 wt.% of 1,4-butyrolactone.

[0031] The waste liquid produced by γ-butyrolactone can be composed of the components shown in Table 1:

[0032] Table 1

[0033]

[0034] The present invention mainly uses pervaporation membrane separation and distillation separation to recycle the above waste liquid. Specifically, it includes the following steps:

[0035] S1, the waste liquid is fed into the first distillation tower 1, the pressure of the first distillation tower 1 is 30KPa absolute pressure, the tower top temperature is 63°C, the tower bottom temperature is 179°C, and the reflux ratio is 3; wherein the gas phase mixture is evaporated from the tower top, and the first tower bottom liquid is produced from the tower bottom;

[0036] S2, the bottom liquid of the first tower enters the second distillation tower 2, the pressure of the second distillation tower 2 is 5KPa absolute pressure, the top temperature is 112.3°C, the bottom temperature is 177.9°C, the reflux ratio is 3, and the crude GBL is obtained from the top of the second distillation tower;

[0037] S3, the gas phase mixture obtained at the top of the first distillation tower 1 is dehydrated by membrane and then enters the third distillation tower 3, with an absolute pressure of 110 KPa, a top temperature of 67.3°C, a bottom temperature of 125.8°C, and a reflux ratio of 5. The gas phase mixture containing THF is extracted from the top of the third distillation tower, and a liquid phase mixture containing NBU is obtained in the bottom of the tower;

[0038] S4, the NBU-containing liquid phase mixture obtained in the bottom of the third distillation tower 3 is fed into the fifth distillation tower 5, the pressure of the fifth distillation tower is 100 KPa absolute pressure, the top temperature is 117.4°C, the bottom temperature is 155.2°C, the reflux ratio is 1.6, and the NBU product is obtained from the top of the fifth distillation tower;

[0039] S5. The gaseous mixture containing THF is taken out from the top of the third distillation tower and enters the fourth distillation tower 4. The pressure is 100 KPa absolute pressure, the top temperature is 60.3°C, the bottom temperature is 72.2°C, and the reflux ratio is 21. THF product is obtained from the bottom of the fourth distillation tower.

[0040] In the above method, the second distillation tower is operated as vacuum distillation, and the vacuum degree is 5 KPa absolute pressure. The theoretical plate numbers of the first distillation tower, the second distillation tower, the third distillation tower and the fifth distillation tower are all 20. The fourth distillation tower has 35 theoretical plates.

[0041] Membrane dehydration, specifically dehydration through pervaporation membrane. The conditions for entering the membrane are a feed liquid with a water content of 15-29wt.%, a pH range of 6.5-8.5, a conductivity of <5μS / cm, and a chloride ion content of ≤20ppm. The membrane operating pressure is an absolute pressure of 300KPa and a flow rate of 12m / s. The gas phase mixture obtained at the top of the first distillation tower can be made to meet the membrane entry conditions through the evaporator 61 and the superheater 62. After the gas phase mixture is dehydrated by the membrane, the water content is reduced to less than 200ppm. The membrane can be made of, for example, NA molecular sieve material.

[0042] In the above method, the waste liquid enters the first distillation tower from the inside of the tower, specifically, from above the 10th tower plate.

[0043] The second distillation tower is entered through the tower, specifically above the 10th tower plate.

[0044] The third distillation tower is entered through the tower, specifically, above the 10th tower plate.

[0045] The fourth distillation tower enters the tower through the tower, specifically above the 30th tower plate.

[0046] The fifth distillation tower enters the tower through the center, specifically above the 10th tower plate.

[0047] By the above method, tetrahydrofuran (THF), NBU and GBL can be separated from the waste liquid, and the purity of the obtained GBL is greater than 99.2wt.%, the purity of butanol is greater than 99.5wt.%, and the purity of tetrahydrofuran is greater than 99.9wt.%.

[0048] Furthermore, the method is implemented by the following device:

[0049] It includes a distillation component, a membrane component, a cooling component and a tower top collection component. Among them, the distillation component includes a first distillation tower 1, a second distillation tower 2, a third distillation tower 3, a fourth distillation tower 4, and a fifth distillation tower 5. The cooling component includes a condenser, a reflux tank, and a pump. The tower top collection component includes a tower top cooler and a distillate temporary storage tank. The specific connection relationship is as follows:

[0050] The top of the first distillation tower 1 is connected to the first cooling assembly, the first cooling assembly is connected to the first tower top collecting assembly, the tower top collecting assembly is connected to the membrane assembly 6, the intercepting side of the membrane assembly is connected to the third distillation tower 3, and the kettle of the first distillation tower 1 is connected to the second distillation tower 2. The top of the second distillation tower 2 is connected to the second cooling assembly, the second cooling assembly is connected to the second tower top collecting assembly, and the second tower top collecting assembly extracts the crude GBL.

[0051] The top of the third distillation tower 3 is connected to the third cooling assembly, the third cooling assembly is connected to the third tower top collecting assembly, the third tower top collecting assembly is connected to the fourth distillation tower 4, and the bottom of the third distillation tower 3 is connected to the fifth distillation tower 5. The bottom of the fourth distillation tower 4 produces THF product.

[0052] The top of the fifth distillation tower 5 is connected to a fifth cooling assembly, the fifth cooling assembly is connected to a fifth tower top collecting assembly, and the NBU product is extracted through the fifth tower top collecting assembly.

[0053] More specifically: the condenser inlet is connected to the top outlet of the distillation tower, the condenser outlet is connected to the reflux tank, the reflux tank is connected to the pump, the pipeline at the pump outlet is divided into two routes, one pipeline enters the top of the next distillation tower, and the other is connected to the top cooler of this distillation tower, the top cooler outlet is connected to the inlet of the distillate temporary storage tank, and the distillate temporary storage tank outlet is connected to the next distillation tower or membrane assembly.

[0054] As a specific embodiment, the above device connection method is as follows:

[0055] The top of the first distillation tower 1 is connected to the first condenser 11, the outlet of the first condenser is connected to the first reflux tank 12, the first reflux tank is connected to the first pump 13, and the outlet of the first pump is divided into two pipelines, one pipeline enters the top of the first distillation tower, and the other enters the first top cooler 14. The outlet of the first top cooler 14 is connected to the first distillate temporary storage tank 15, and the first distillate temporary storage tank 15 is connected to the evaporator 61 through the first transfer pump 16. The evaporator is connected to the superheater 62, and the superheater is connected to the membrane assembly 6. The intercepting side of the membrane assembly is connected to the finished product condenser 63, and the outlet of the finished product condenser 63 is connected to the membrane finished product tank 64, and the membrane finished product tank 64 is connected to the transfer pump 65, and the transfer pump 65 is connected to the third distillation tower 3.

[0056] The bottom of the first distillation tower 1 is connected to the second distillation tower 2 through the first bottom pump 17. The top of the second distillation tower 2 is connected to the outlet of the second condenser 21, which is connected to the second reflux tank 22. The second reflux tank is connected to the second pump 23. The pipeline at the outlet of the second pump is divided into two branches, one of which enters the top of the second distillation tower 2, and the other enters the second top cooler 24. The outlet of the second top cooler 24 is connected to the second distillate temporary storage tank 25, and the second distillate temporary storage tank is connected to the second material transfer pump 26 to produce the crude GBL product.

[0057] The top of the third distillation tower 3 is connected to the outlet of the third condenser 31, which is connected to the third reflux tank 32. The third reflux tank is connected to the third pump 33. The pipeline at the outlet of the third pump is divided into two branches, one of which enters the top of the third distillation tower 3 and the other enters the third tower top cooler 34. The outlet of the third tower top cooler 34 is connected to the third distillate temporary storage tank 35. The third distillate temporary storage tank is connected to the third material transfer pump 36. The third material transfer pump 36 is connected to the fourth distillation tower 4. The bottom of the third distillation tower 3 is connected to the fifth distillation tower 5 through the third bottom pump 37.

[0058] The top of the fourth distillation tower is connected to the outlet of the fourth condenser 41 connected to the fourth reflux tank 42, the fourth reflux tank is connected to the fourth pump 43, the outlet pipeline of the fourth pump is divided into two branches, one pipeline enters the top of the fourth distillation tower, and the other enters the fourth tower top cooler 44, the outlet of the fourth tower top cooler is connected to the fourth distillate temporary storage tank 45, the fourth distillate temporary storage tank 45 is connected to the fourth material transfer pump 46, and the fourth material transfer pump 46 extracts impurities. The fourth distillation tower 4 bottom is pumped out by the fourth tower bottom pump 47.

[0059] The top of the fifth distillation tower 5 is connected to the outlet of the fifth condenser 51 connected to the fifth reflux tank 52, the fifth reflux tank is connected to the fifth pump 53, the outlet pipeline of the fifth pump is divided into two branches, one pipeline enters the top of the fifth distillation tower, and the other enters the fifth tower top cooler 54, the outlet of the fifth tower top cooler is connected to the fifth distillate temporary storage tank 55, the fifth distillate temporary storage tank is connected to the fifth material transfer pump 56, and the fifth material transfer pump 56 extracts NBU. The fifth distillation tower 5 bottom is pumped out with the fifth bottom pump 57 to extract impurities.

[0060] The method of the present invention is described in detail below in conjunction with specific embodiments:

[0061] Example 1 The content in the waste liquid is shown in Table 2 below

[0062] Table 2

[0063]

[0064] The waste liquid enters from the top of the 10th plate in the first distillation tower. The absolute pressure of the first distillation tower is 30KPa, the top temperature is 63℃, the bottom temperature is 179℃, the reflux ratio is 3, and the theoretical number of plates is 20. The gas phase mixture evaporated from the top of the tower passes through the first condenser, the first reflux tank, the first pump, and the first top cooler. The gas phase mixture passes through the first top cooler, the first distillate temporary storage tank, and then passes through the first transfer pump to enter the evaporator for heating at a temperature of 119℃. After passing through the evaporator, it enters the superheater with a superheater temperature of 134℃. After reaching the membrane entry conditions, it enters the membrane assembly for dewatering. The operating parameters of the membrane assembly are 120~135℃. Through the membrane assembly, the product on the interception side of the membrane assembly enters the finished product condenser, cools to 45℃, and then enters the membrane finished product tank, and then enters the third distillation tower through the transfer pump. The first bottom liquid extracted from the bottom of the first distillation tower contains GBL and heavy component impurities.

[0065] The first bottom liquid is pumped into the second distillation tower through the first bottom, and enters from the top of the 10th plate in the second distillation tower. The absolute pressure of the second distillation tower is 5KPa, the top temperature is 112.3℃, the bottom temperature is 177.9℃, the reflux ratio is 3, and the theoretical plate number is 20. The GBL gas phase product is extracted from the top of the second distillation tower, and passes through the second condenser, the second reflux tank, and the second pump. The extracted GBL gas phase passes through the second pump, the second top cooler, the second distillate temporary storage tank, and is connected to the second transfer pump to extract the GBL crude product.

[0066] After passing through the membrane finished product tank, the product from the transfer pump enters the third distillation tower from above the 10th tray in the tower. The absolute pressure of the third distillation tower is 110KPa, the top temperature is 67.3℃, the bottom temperature is 125.8℃, the reflux ratio is 5, and the number of trays is 20. THF and NBU are separated by the third distillation tower, and THF and part of the impurity gas phase pass through the top of the third distillation tower into the third condenser, the third reflux tank, the third pump, the third top cooler, the third distillate temporary storage tank, and the third transfer pump into the fourth distillation tower. The bottom liquid in the third distillation tower contains NBU and is pumped into the fifth distillation tower through the third bottom.

[0067] The THF-containing gas phase mixture enters the fourth distillation tower above the 30th plate. The fourth distillation tower has an absolute pressure of 100 KPa, a top temperature of 60.3°C, a bottom temperature of 72.2°C, a reflux ratio of 21, and a theoretical plate number of 35. The fourth distillation tower bottom is pumped to produce THF products. Impurities are produced from the top of the fourth distillation tower.

[0068] The bottom liquid in the third distillation tower contains NBU and enters the top of the 10th tower plate in the fifth distillation tower. The absolute pressure of the fifth distillation tower is 100KPa, the top temperature is 117.4℃, the bottom temperature is 155.2℃, the reflux ratio is 1.6, and the theoretical number of plates is 20. The NBU product is evaporated through the fifth distillation tower, and the NBU product is extracted through the fifth condenser, the fifth reflux tank, the fifth pump, the fifth tower top cooler, the fifth distillate temporary storage tank, and the fifth material transfer pump.

[0069] By using the above separation device, it is possible to obtain GBL purity > 99.2wt.%, butanol purity > 99.5wt.%, and tetrahydrofuran purity > 99.9wt.%.

Claims

1. A method for recovering and separating waste liquid generated by the production of γ-butyrolactone; characterized in that: The method comprises the following steps: S1, the waste liquid is put into the first distillation tower, the gas phase mixture is evaporated from the top of the tower, and the first bottom liquid is extracted from the bottom of the tower; S2, the bottom liquid of the first tower is fed into the second distillation tower, and the crude GBL is obtained from the top of the second distillation tower; S3, the gas phase mixture obtained at the top of the first distillation tower is dehydrated by a membrane and then enters the third distillation tower, the gas phase mixture containing THF is extracted from the top of the third distillation tower, and the liquid phase mixture containing NBU is obtained in the kettle of the third distillation tower; S4, the NBU-containing liquid phase mixture obtained in the kettle of the third distillation tower is fed into the fifth distillation tower, and the NBU product is obtained from the top of the fifth distillation tower; S5. The gas phase mixture containing THF is taken out from the top of the third distillation tower and fed into the fourth distillation tower, and the THF product is obtained from the bottom of the fourth distillation tower.

2. The method for recovering and separating waste liquid generated by producing γ-butyrolactone according to claim 1, characterized in that: The operating parameters of the first distillation tower are as follows: absolute pressure of 30 KPa, tower top temperature of 63 °C, tower bottom temperature of 179 °C, and reflux ratio of 3; the operating parameters of the second distillation tower are as follows: absolute pressure of 5 KPa, tower top temperature of 112.3 °C, tower bottom temperature of 177.9 °C, and reflux ratio of 3; the operating parameters of the third distillation tower are as follows: absolute pressure of 110 KPa, tower top temperature of 67.3 °C, tower bottom temperature of 125.8 °C, and reflux ratio of 5; the operating parameters of the fourth distillation tower are as follows: absolute pressure of 100 KPa, tower top temperature of 60.3 °C, tower bottom temperature of 72.2 °C, and reflux ratio of 21; the operating parameters of the fifth distillation tower are as follows: absolute pressure of 100 KPa, tower top temperature of 117.4 °C, tower bottom temperature of 155.2 °C, and reflux ratio of 1.

6.

3. The method for recovering and separating waste liquid generated by producing γ-butyrolactone according to claim 1, characterized in that: The number of theoretical plates of the first distillation tower, the second distillation tower, the third distillation tower and the fifth distillation tower are all 20; the number of theoretical plates of the fourth distillation tower is 35.

4. The method for recovering and separating waste liquid generated by producing γ-butyrolactone according to claim 3, characterized in that: The waste liquid enters the first distillation tower, specifically from the top of the 10th tower plate; the waste liquid enters the second distillation tower through the tower, specifically from the top of the 10th tower plate; the waste liquid enters the third distillation tower through the tower, specifically from the top of the 10th tower plate; the waste liquid enters the fourth distillation tower through the tower, specifically from the top of the 30th tower plate; the waste liquid enters the fifth distillation tower through the tower, specifically from the top of the 10th tower plate.

5. The method for recovering and separating waste liquid generated by producing γ-butyrolactone according to claim 1, characterized in that: The waste liquid generated by the production of γ-butyrolactone includes 17.802-35.604 wt.%, tetrahydrofuran, 12.864-25.728 wt.%, water, 10.572-21.144 wt.%, butanol, and 10.752-21.504 wt.% of 1,4-butyrolactone GBL.

6. A waste liquid recovery and separation device for producing γ-butyrolactone, comprising a distillation component, a membrane component (6), a cooling component, and a tower top collection component, characterized in that: The distillation component comprises a first distillation tower (1), a second distillation tower (2), a third distillation tower (3), a fourth distillation tower (4), and a fifth distillation tower (5); the cooling component comprises a condenser, a reflux tank, and a pump; the tower top collection component comprises a tower top cooler and a distillate temporary storage tank; The top of the first distillation tower (1) is connected in sequence to a first cooling assembly, a first tower top collecting assembly, and a membrane assembly (6); the intercepting side of the membrane assembly is connected to a third distillation tower (3); the bottom of the first distillation tower (1) is connected to a second distillation tower (2); the top of the second distillation tower (2) is connected in sequence to a second cooling assembly and a second tower top collecting assembly; the second tower top collecting assembly extracts a crude GBL product; The top of the third distillation tower (3) is connected in sequence to a third cooling assembly, a third top collecting assembly, and a fourth distillation tower (4); the bottom of the third distillation tower (3) is connected to a fifth distillation tower (5); and the bottom of the fourth distillation tower (4) produces a THF product; The top of the fifth distillation tower (5) is connected in sequence to a fifth cooling assembly and a fifth tower top collecting assembly, and the NBU product is extracted through the fifth tower top collecting assembly.

7. The waste liquid recovery and separation device for producing γ-butyrolactone according to claim 6, characterized in that: An evaporator (61) and a superheater (62) are also provided after the first tower top collecting assembly; the first tower top collecting assembly is sequentially connected to the evaporator (61), the superheater (62), and the membrane assembly (6).

8. The waste liquid recovery and separation device for producing γ-butyrolactone according to claim 7, characterized in that: The top of the first distillation tower (1) is connected to a first condenser (11), the outlet of the first condenser is connected to a first reflux tank (12), the first reflux tank is connected to a first pump (13), the outlet pipeline of the first pump is divided into two routes, one route enters the top of the first distillation tower, and the other route enters the first tower top cooler (14), the outlet of the first tower top cooler (14) is connected to a first distillate temporary storage tank (15), the first distillate temporary storage tank (15) is connected to an evaporator (61) via a first material transfer pump (16), the evaporator is connected to a superheater (62), the superheater is connected to a membrane module (6), the intercepting side of the membrane module is connected to a finished product condenser (63), the outlet of the finished product condenser (63) is connected to a membrane finished product tank (64), the membrane finished product tank (64) is connected to a transfer pump (65), and the transfer pump (65) is connected to a third distillation tower (3); The bottom of the first distillation tower (1) is connected to the second distillation tower (2) via a first bottom pump (17); the top of the second distillation tower (2) is connected to a second condenser (21); the outlet is connected to a second reflux tank (22); the second reflux tank is connected to a second pump (23); the outlet pipeline of the second pump is divided into two branches, one of which enters the top of the second distillation tower (2); the other enters the second top cooler (24); the outlet of the second top cooler (24) is connected to a second distillate temporary storage tank (25); the second distillate temporary storage tank is connected to a second material transfer pump (26) to produce a crude GBL product; The top of the third distillation tower (3) is connected to the third condenser (31), the outlet of which is connected to the third reflux tank (32), the third reflux tank is connected to the third pump (33), the outlet pipeline of the third pump is divided into two branches, one pipeline enters the top of the third distillation tower (3), and the other pipeline enters the third tower top cooler (34), the outlet of the third tower top cooler (34) is connected to the third distillate temporary storage tank (35), the third distillate temporary storage tank is connected to the third material transfer pump (36), and the third material transfer pump (36) is connected to the fourth distillation tower (4); the bottom of the third distillation tower (3) is connected to the fifth distillation tower (5) through the third bottom pump (37); The top of the fourth distillation tower is connected to the fourth condenser (41), the outlet of which is connected to the fourth reflux tank (42), the fourth reflux tank is connected to the fourth pump (43), the outlet pipeline of the fourth pump is divided into two branches, one pipeline enters the top of the fourth distillation tower, and the other pipeline enters the fourth tower top cooler (44), the outlet of the fourth tower top cooler is connected to the fourth distillate temporary storage tank (45), the fourth distillate temporary storage tank (45) is connected to the fourth material transfer pump (46), and the fourth material transfer pump (46) extracts impurities; the bottom of the fourth distillation tower (4) extracts THF product through the fourth bottom pump (47); The top of the fifth distillation tower (5) is connected to the outlet of the fifth condenser (51) connected to the fifth reflux tank (52), the fifth reflux tank is connected to the fifth pump (53), the outlet pipeline of the fifth pump is divided into two branches, one pipeline enters the top of the fifth distillation tower, and the other pipeline enters the fifth tower top cooler (54), the outlet of the fifth tower top cooler is connected to the fifth distillate temporary storage tank (55), the fifth distillate temporary storage tank is connected to the fifth material transfer pump (56), and the fifth material transfer pump (56) extracts NBU.

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