Separating and refining device system and separating method for coal-based mixed alcohol

Abstract

The invention relates to a separating and refining device system and a separating method for coal-based mixed alcohols, and the separating and refining device system comprises a vacuum rectification unit, a continuous adsorption separation unit and an eluent removal unit which are sequentially connected along a material flow direction, an eluent discharged by the eluent removal unit is recycled for the continuous adsorption separation unit, and ethylene glycol discharged by the eluent removal unit is recycled for the vacuum rectification unit. According to the method, the ethylene glycol and the 1, 2-butanediol are efficiently separated by adopting a vacuum distillation and adsorption separation coupling process, and the obtained ethylene glycol and 1, 2-butanediol products have relatively high purity and yield; the method is easy to operate, high in safety, low in energy consumption, capable of saving energy and wide in application range.

Description

Technical Field

[0001] The present invention relates to the technical field of organic separation, and in particular to a separation and purification device system and a separation method for coal-based mixed alcohol. Background Art

[0002] The coal-to-ethylene glycol production process produces a mixed diol byproduct composed primarily of ethylene glycol and 1,2-butanediol. The boiling points of ethylene glycol and 1,2-butanediol differ by 4.5°C, and they form a minimum azeotrope, making complete separation difficult using conventional distillation techniques. Therefore, separation and purification technologies for coal-based mixed alcohols have become a research hotspot.

[0003] Currently, commonly used methods for separating ethylene glycol and 1,2-butanediol include vacuum distillation, azeotropic distillation, and reactive distillation. US 4966658A discloses a method for separating ethylene glycol and butanediol using azeotropic distillation. This method introduces a third component (an entrainer) into the mixed alcohol azeotropic system to increase the relative volatility of the original system, thereby achieving separation of ethylene glycol or 1,2-butanediol. However, the entrainer must be separated and recycled in subsequent steps, requiring additional distillation equipment and process flows, resulting in increased energy consumption.

[0004] US 9227896A discloses a method for separating ethylene glycol and butanediol by extractive distillation. Extractive distillation also involves introducing a third component (extractant) into a mixed alcohol system to change the relative volatility of the components to be separated. The difference is that the extractant forms an azeotropic system with the mixed alcohol system, and the boiling point of the extractant is also higher than that of the diol. However, ethylene glycol and 1,2-butanediol have similar polarities and high boiling points, making it difficult to find a suitable high-boiling-point extractant.

[0005] CN 105541551A discloses a method for separating ethylene glycol and 1,2-butanediol using reactive distillation. Reactive distillation involves introducing a third component into a mixed system that can rapidly undergo a reversible reaction with ethylene glycol or 1,2-butanediol to increase their relative volatility, ultimately achieving separation of the two. However, currently commonly used aldehyde and ketone reaction entrainers have the disadvantages of high toxicity, a long process flow, complex equipment, and high cost, which do not conform to the concept of green chemical engineering.

[0006] Adsorption separation is also a method for separating ethylene glycol from 1,2-butanediol. Compared to other mixed alcohol separation processes, it offers low energy consumption, is non-toxic, and employs mild conditions. Adsorption separation utilizes the differences in adsorption properties of the adsorbent to separate different components and is generally suitable for separating mixed systems with similar physical and chemical properties. Simulated moving bed technology, developed based on chromatographic separation, offers continuous operation and is suitable for the efficient separation of ethylene glycol from 1,2-butanediol.

[0007] CN 112979419A discloses a method for separating ethylene glycol and 1,2-butanediol using a sequential simulated moving bed. By regulating the flow rates and timing of feed and discharge in each zone of the sequential simulated moving bed, efficient separation of ethylene glycol and 1,2-butanediol is achieved. However, the ethylene glycol and 1,2-butanediol products obtained by using the sequential simulated moving bed are difficult to meet premium quality standards. Specifically, the crude ethylene glycol product has a low purity and is difficult to meet national standards for qualified products. Furthermore, due to the wide variety of sources for coal-based mixed alcohols, the composition of the mixed alcohols produced as byproducts varies from manufacturer to manufacturer and from coal-to-ethylene glycol technology routes, seriously impacting the stable operation of the simulated moving bed.

[0008] How is the problem that needs to be solved urgently?

[0009] Therefore, in view of the shortcomings of the existing technology, there is an urgent need to provide a separation and purification device system that can separate and purify coal-based mixed alcohols while obtaining high-purity ethylene glycol and 1,2-butanediol. Summary of the Invention

[0010] The purpose of the present invention is to provide a separation and purification device system and separation method for coal-based mixed alcohols. According to the composition of the coal-based mixed alcohols, suitable separation and purification devices are used to purify and separate ethylene glycol and 1,2-butanediol. The system has the characteristics of simple operation, high safety, low energy consumption and wide application range.

[0011] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0012] In the first aspect, the present invention provides a separation and refining device system for coal-based mixed alcohol, which includes a vacuum distillation unit, a continuous adsorption separation unit, and an eluent removal unit connected in sequence along the material flow direction. The eluent discharged from the eluent removal unit is recycled back to the continuous adsorption separation unit, and the ethylene glycol discharged from the eluent removal unit is recycled back to the vacuum distillation unit.

[0013] The coal-based mixed alcohol separation and purification device system provided by the present invention adopts a vacuum distillation and adsorption separation coupling process to efficiently separate ethylene glycol and 1,2-butanediol. By adopting a suitable separation and purification device for purification, distillation, adsorption separation and eluent removal are carried out in sequence to separate ethylene glycol and 1,2-butanediol, thereby obtaining high-purity ethylene glycol and 1,2-butanediol products.

[0014] Preferably, the vacuum distillation unit comprises a vacuum distillation device, the top of the vacuum distillation device is connected to a cooling component, the bottom is connected to a heating component, and the side walls are respectively connected to a feeding component and a polyester-grade ethylene glycol storage device.

[0015] Preferably, the number of baffles in the vacuum distillation device is 20 to 50, for example, 20, 25, 30, 40 or 50, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, the vacuum distillation device includes a vacuum distillation tower.

[0017] Preferably, the polyester-grade ethylene glycol storage device comprises a polyester-grade ethylene glycol storage tank.

[0018] Preferably, the cooling assembly includes a condenser, a top reflux device and a reflux pump connected in sequence along the material flow direction, the inlet of the condenser is connected to the top outlet of the vacuum distillation device, the outlet of the reflux pump is connected to the reflux port of the vacuum distillation device, and the outlet of the top reflux device is also connected to the continuous adsorption separation unit.

[0019] Preferably, the top reflux device comprises a top reflux tank.

[0020] Preferably, the heating component includes a circulation pump, the inlet of the circulation pump is connected to the bottom outlet of the vacuum distillation device, and the outlet of the circulation pump is respectively connected to a reboiler and an ethylene glycol storage device, and the material discharged from the reboiler is returned to the vacuum distillation device.

[0021] Preferably, the ethylene glycol storage device comprises an ethylene glycol storage tank.

[0022] Preferably, the feed assembly includes a first feed pump and a second feed pump, the outlet of the first feed pump is connected to the first feed port of the vacuum distillation device, the outlet of the second feed pump is connected to the second feed port of the vacuum distillation device, and the inlet of the second feed pump is connected to the eluent removal unit.

[0023] Preferably, the continuous adsorption separation unit comprises a sequential simulated moving bed and a preheater connected to the feed inlet of the sequential simulated moving bed, and the preheater is connected to the outlet of the top reflux device.

[0024] In the present invention, a sequential simulated moving bed is selected as the adsorption separation device, which has a relatively stable operation and significantly reduces the processing scale of the device.

[0025] Preferably, the sequential simulated moving bed is provided with 6 to 12 chromatographic columns in parallel, for example, 6, 8, 10 or 12 columns, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] Preferably, the chromatographic column is filled with any one of resin, molecular sieve or activated carbon.

[0027] Preferably, a top control valve is provided at the top of the chromatographic column, and the top control valve is respectively connected to the feed pipeline and the eluent pipeline of the sequential simulated moving bed; a bottom control valve is provided at the bottom end of the chromatographic column, and the bottom control valve is respectively connected to the raffinate discharge pipeline and the extract discharge pipeline of the sequential simulated moving bed; a pipeline control valve is provided between the chromatographic columns, and the pipeline control valve is connected to the chromatographic columns of the sequential simulated moving bed.

[0028] Preferably, the eluent removal unit includes an ethylene glycol dehydration device, a 1,2-butanediol dehydration device, a 1,2-butanediol storage device and an eluent storage device; the feed port of the ethylene glycol dehydration device is connected to the raffinate discharge port of the sequential simulated moving bed, the top outlet of the ethylene glycol dehydration device is connected to the eluent storage device, and the bottom outlet of the ethylene glycol dehydration device is connected to the inlet of the second feed pump; the feed port of the 1,2-butanediol dehydration device is connected to the extract discharge port of the sequential simulated moving bed, the top outlet of the 1,2-butanediol dehydration device is connected to the eluent storage device, and the bottom outlet of the 1,2-butanediol dehydration device is connected to the 1,2-butanediol storage device; the eluent storage device is connected to the sequential simulated moving bed through an eluent delivery pump.

[0029] Preferably, the ethylene glycol dehydration device comprises an ethylene glycol dehydration tower.

[0030] Preferably, the 1,2-butanediol dehydration device comprises a 1,2-butanediol dehydration tower.

[0031] Preferably, the 1,2-butanediol storage device comprises a 1,2-butanediol storage tank.

[0032] Preferably, the eluent storage device comprises an eluent storage tank.

[0033] Preferably, the number of baffles in the ethylene glycol dehydration device is 25 to 50, for example, 25, 30, 35, 40 or 50, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the number of baffles in the 1,2-butanediol dehydration device is 30 to 50, for example, 30, 35, 40, 45 or 50, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] In a second aspect, the present invention provides a method for separating coal-based mixed alcohols, the separation method being performed by the separation and refining device system described in the first aspect, the separation method comprising the following steps:

[0036] (1) subjecting the coal-based mixed alcohol to vacuum distillation to obtain a top-extracted component, a bottom-extracted component, and polyester-grade ethylene glycol;

[0037] (2) subjecting the top extracted component obtained in step (1) to an adsorption separation treatment, wherein an eluent is added during the adsorption separation treatment to obtain a raffinate and an extract; a portion of the bottom extracted component obtained in step (1) is reboiled and then returned to a vacuum distillation treatment, and a portion is extracted to obtain ethylene glycol;

[0038] (3) The extract obtained in step (2) is subjected to a first eluent removal treatment to obtain 1,2-butanediol; the obtained raffinate is subjected to a second eluent removal treatment and then returned for vacuum distillation.

[0039] The method for separating coal-based mixed alcohols provided by the present invention is carried out by the separation and refining device system, wherein the coal-based mixed alcohols are sequentially subjected to vacuum distillation treatment, adsorption separation treatment, and eluent removal treatment, thereby achieving efficient separation of ethylene glycol and 1,2-butanediol. The obtained ethylene glycol and 1,2-butanediol products have high purity and concentration. The method is simple to operate, highly safe, has low energy consumption, saves energy, and has a wide range of applications.

[0040] Preferably, the source of the coal-based mixed alcohol in step (1) includes by-products of a coal-to-ethylene glycol reaction process.

[0041] Preferably, the coal-based mixed alcohol in step (1) comprises ethylene glycol, 1,2-butanediol and an eluent.

[0042] Preferably, the mass percentage of ethylene glycol in the coal-based mixed alcohol is 35-45 wt%, and the mass percentage of 1,2-butanediol is 15-25 wt%.

[0043] The mass percentage of ethylene glycol in the coal-based mixed alcohol is 35-45wt%, for example, it can be 35wt%, 38wt%, 40wt%, 42wt% or 45wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] The mass percentage of 1,2-butanediol in the coal-based mixed alcohol is 15-25wt%, for example, it can be 15wt%, 18wt%, 20wt%, 22wt% or 25wt%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0045] Preferably, the operating pressure of the vacuum distillation treatment in step (1) is 5 to 50 kPa, for example, 5 kPa, 10 kPa, 25 kPa, 40 kPa or 50 kPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0046] Preferably, the bottom temperature of the vacuum distillation device where the vacuum distillation treatment is carried out in step (1) is 70-140°C, and the top temperature is 20-80°C.

[0047] The bottom temperature of the vacuum distillation device is 70-140°C, for example, 70°C, 90°C, 110°C, 130°C or 140°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0048] The top temperature of the vacuum distillation device is 20-80°C, for example, 20°C, 30°C, 40°C, 60°C or 80°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0049] Preferably, the reflux ratio of the vacuum distillation treatment in step (1) is (2 to 25):1, for example, it can be 2:1, 5:1, 10:1, 20:1 or 25:1, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0050] Preferably, the top-extracted components in step (1) include 30-50 wt% of eluent, 25-35 wt% of ethylene glycol and 25-35 wt% of 1,2-butanediol.

[0051] The mass percentage of the eluent is 30-50wt%, for example, 30wt%, 35wt%, 40wt%, 45wt% or 50wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0052] The mass percentage of the ethylene glycol is 25-35wt%, for example, it can be 25wt%, 28wt%, 30wt%, 32wt% or 35wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] The mass percentage of the 1,2-butanediol is 25-35wt%, for example, 25wt%, 28wt%, 30wt%, 32wt% or 35wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0054] Preferably, the bottom extraction component in step (1) includes 95-98 wt% of ethylene glycol, for example, it can be 95 wt%, 96 wt%, 97 wt% or 98 wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] Preferably, the polyester-grade ethylene glycol in step (1) contains >99.9 wt% of ethylene glycol, for example, 99.92 wt%, 99.93 wt%, 99.95 wt% or 99.98 wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] Preferably, before the adsorption separation treatment in step (2), the top extracted components are condensed, and part of the resulting condensate is refluxed for vacuum distillation treatment, and part is subjected to adsorption separation treatment.

[0057] Preferably, the eluent in step (2) comprises any one or a combination of at least two of ultrapure water, ethanol aqueous solution or methanol. Typical but non-limiting combinations include a combination of ultrapure water and ethanol aqueous solution, a combination of ethanol aqueous solution and methanol, or a combination of ultrapure water, ethanol aqueous solution and methanol.

[0058] Preferably, the volume ratio of ethanol to water in the ethanol aqueous solution is 1:(1-9), for example, it can be 1:1, 1:3, 1:5, 1:7 or 1:9, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] Preferably, the operating temperature of the adsorption separation treatment in step (2) is 40-70° C., and the operating pressure is normal pressure.

[0060] The operating temperature of the adsorption separation treatment is 40-70°C, for example, 40°C, 45°C, 50°C, 60°C or 70°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0061] Preferably, the operating pressure of the first eluent removal treatment in step (3) is 5 to 50 kPa, for example, 5 kPa, 10 kPa, 20 kPa, 30 kPa or 50 kPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0062] Preferably, the bottom temperature of the 1,2-butanediol dehydration device where the first eluent removal treatment is carried out in step (3) is 70-140°C, and the top temperature is 20-80°C.

[0063] The bottom temperature of the 1,2-butanediol dehydration device is 70-140°C, for example, 70°C, 90°C, 100°C, 120°C or 140°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] The top temperature of the 1,2-butanediol dehydration device is 20-80°C, for example, 20°C, 30°C, 40°C, 60°C or 80°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0065] Preferably, the reflux ratio of the first eluent removal treatment in step (3) is (1 to 5):1, for example, it can be 1:1, 2:1, 3:1, 4:1 or 5:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0066] Preferably, after the first eluent is removed in step (3), an eluent with a mass percentage of ≥99.9wt% and a 1,2-butanediol with a mass percentage of ≥98wt% are obtained, and the obtained eluent is reused in the adsorption separation treatment.

[0067] The mass percentage of the eluent is ≥99.9wt%, for example, it can be 99.9wt%, 99.92wt%, 99.93wt%, 99.95wt% or 99.97wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0068] The mass percentage of the 1,2-butanediol is ≥98wt%, for example, it can be 98wt%, 98.2wt%, 98.5wt%, 98.8wt% or 99wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0069] Preferably, it is characterized in that the operating pressure of the second eluent removal treatment in step (3) is 5 to 50 kPa, for example, it can be 5 kPa, 10 kPa, 20 kPa, 30 kPa or 50 kPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0070] Preferably, the bottom temperature of the glycol dehydration device where the second eluent removal treatment is carried out in step (3) is 70-140°C, and the top temperature is 20-80°C.

[0071] The bottom temperature of the glycol dehydration device is 70-140°C, for example, 70°C, 90°C, 100°C, 120°C or 140°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0072] The top temperature of the glycol dehydration device is 20-80°C, for example, 20°C, 30°C, 40°C, 60°C or 80°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0073] Preferably, the reflux ratio of the second eluent removal treatment in step (3) is (1 to 5):1, for example, it can be 1:1, 2:1, 3:1, 4:1 or 5:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0074] Preferably, after the second eluent is removed in step (3), an eluent with a mass percentage of ≥99.9wt% and an ethylene glycol with a mass percentage of ≥95wt% are obtained, and the obtained eluent is reused in the adsorption separation treatment, and the obtained ethylene glycol is returned for vacuum distillation treatment.

[0075] The mass percentage of the eluent is ≥99.9wt%, for example, it can be 99.9wt%, 99.92wt%, 99.93wt%, 99.95wt% or 99.97wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0076] The mass percentage of the ethylene glycol is ≥95wt%, for example, it can be 95wt%, 95.5wt%, 96wt%, 97wt% or 98wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0077] The method for separating coal-based mixed alcohols provided by the present invention is carried out by the separation and refining device system. The specific steps of the operation of the separation and refining device system include three stages. The first stage: the vacuum distillation device separates and refines the coal-based mixed alcohol and the recovered ethylene glycol, and the azeotropic mixture of ethylene glycol and 1,2-butanediol is extracted from the top, and then enters the sequential simulated moving bed for adsorption separation treatment, polyester-grade ethylene glycol is extracted from the waist, and ethylene glycol is extracted from the bottom; the second stage: the eluent and the azeotropic mixture enter the sequential simulated moving bed, and the operation sequence of the sequential simulated moving bed is adjusted. As well as the flow rate and time of feed and discharge, the azeotropic mixture is separated by periodic adsorption and desorption, the extracted extract enters the 1,2-butanediol dehydration device, and the extracted raffinate enters the ethylene glycol dehydration device; the third stage: the eluent is extracted from the top of the ethylene glycol dehydration device and enters the eluent storage device, the ethylene glycol is extracted from the bottom and enters the vacuum distillation device through the raw material delivery pump to form a circulation loop, the eluent is extracted from the top of the 1,2-butanediol dehydration device and enters the eluent storage device, and the 1,2-butanediol is extracted from the bottom and enters the 1,2-butanediol storage device.

[0078] Compared with the prior art, the present invention has the following beneficial effects:

[0079] The coal-based mixed alcohol separation and purification device system provided by the present invention adopts a vacuum distillation and adsorption separation coupling process to efficiently separate ethylene glycol and 1,2-butanediol. By adopting a suitable separation and purification device for purification, distillation, adsorption separation and eluent removal are sequentially performed to achieve efficient separation of ethylene glycol and 1,2-butanediol. The obtained ethylene glycol and 1,2-butanediol products have high purity and yield. The method is simple to operate, highly safe, low in energy consumption, energy-saving, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Figure 1 Schematic diagram of the structure of the separation and purification device system provided in Example 1 of the present invention;

[0081] Wherein: 1, vacuum distillation tower; 2, polyester-grade ethylene glycol storage tank; 3, condenser; 4, top reflux tank; 5, reflux pump; 6, circulation pump; 7, reboiler; 8, ethylene glycol storage tank; 9, first feed pump; 10, second feed pump; 11, sequential simulated moving bed; 12, preheater; 13, chromatographic column; 14, ethylene glycol dehydration tower; 15, 1,2-butanediol dehydration tower; 16, 1,2-butanediol storage tank; 17, eluent storage tank; 18, eluent delivery pump. DETAILED DESCRIPTION

[0082] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0083] Example 1

[0084] This embodiment provides a separation and purification device system for coal-based mixed alcohol, such as Figure 1 As shown, the separation and refining device system includes a vacuum distillation unit, a continuous adsorption separation unit, and an eluent removal unit connected in sequence along the material flow direction. The eluent discharged from the eluent removal unit is recycled back to the continuous adsorption separation unit, and the ethylene glycol discharged from the eluent removal unit is recycled back to the vacuum distillation unit.

[0085] The vacuum distillation unit includes a vacuum distillation tower 1, the top of which is connected to a cooling assembly, the bottom of which is connected to a heating assembly, and the side walls of which are respectively connected to a feed assembly and a polyester-grade ethylene glycol storage tank 2; the number of baffles in the vacuum distillation tower 1 is 30;

[0086] The cooling assembly includes a condenser 3, a top reflux tank 4 and a reflux pump 5 connected in sequence along the material flow direction, the inlet of the condenser 3 is connected to the top outlet of the vacuum distillation tower 1, the outlet of the reflux pump 5 is connected to the reflux port of the vacuum distillation tower 1, and the outlet of the top reflux tank 4 is also connected to the continuous adsorption separation unit; the heating assembly includes a circulating pump 6, the inlet of the circulating pump 6 is connected to the bottom outlet of the vacuum distillation tower 1, and the outlet of the circulating pump 6 is respectively connected to a reboiler 7 and an ethylene glycol storage tank 8, and the material discharged from the reboiler 7 is returned to the vacuum distillation tower 1; the feeding assembly includes a first feed pump 9 and a second feed pump 10, the outlet of the first feed pump 9 is connected to the first feed port of the vacuum distillation tower 1, the outlet of the second feed pump 10 is connected to the second feed port of the vacuum distillation tower 1, and the inlet of the second feed pump 10 is connected to the eluent removal unit;

[0087] The continuous adsorption separation unit includes a sequential simulated moving bed 11 and a preheater 12 connected to the feed port of the sequential simulated moving bed 11, and the preheater 12 is connected to the outlet of the top reflux tank 4; the sequential simulated moving bed 11 is provided with 6 chromatographic columns 13 in parallel; the chromatographic columns 13 are filled with molecular sieves; the top of the chromatographic column 13 is provided with a top control valve, and the top control valve is respectively connected to the feed pipeline and the eluent pipeline of the sequential simulated moving bed 11; the bottom end of the chromatographic column 13 is provided with a bottom control valve, and the bottom control valve is respectively connected to the raffinate discharge pipeline and the extract discharge pipeline of the sequential simulated moving bed 11; a pipeline control valve is provided between the chromatographic columns 13, and the pipeline control valve is connected to the chromatographic column 13 of the sequential simulated moving bed 1;

[0088] The eluent removal unit includes an ethylene glycol dehydration tower 14, a 1,2-butanediol dehydration tower 15, a 1,2-butanediol storage tank 16 and an eluent storage tank 17; the feed port of the ethylene glycol dehydration tower 14 is connected to the raffinate discharge port of the sequential simulated moving bed 11, the top outlet of the ethylene glycol dehydration tower 14 is connected to the eluent storage tank 17, the bottom outlet of the ethylene glycol dehydration tower 13 is connected to the inlet of the second feed pump 10; the feed port of the 1,2-butanediol dehydration tower 15 is connected to the The extract discharge port of the sequential simulated moving bed 11 is connected, the top outlet of the 1,2-butanediol dehydration tower 15 is connected to the eluent storage tank 17, and the bottom outlet of the 1,2-butanediol dehydration tower 15 is connected to the 1,2-butanediol storage tank 16; the eluent storage tank 17 is connected to the sequential simulated moving bed 11 through an eluent delivery pump 18; the number of baffles in the ethylene glycol dehydration tower 14 is 35; the number of baffles in the 1,2-butanediol dehydration tower 15 is 40.

[0089] Example 2

[0090] This embodiment provides a separation and purification device system for coal-based mixed alcohols. The difference from Example 1 is that the number of partitions in the vacuum distillation tower 1 is adjusted to 20; the number of chromatographic columns 13 arranged in parallel with the sequential simulated moving bed 11 is adjusted to 8; the material filled in the chromatographic column 13 is replaced with activated carbon; the number of partitions in the ethylene glycol dehydration tower 14 is adjusted to 25; the number of partitions in the 1,2-butanediol dehydration tower 15 is adjusted to 30, and the rest are the same as Example 1.

[0091] Example 3

[0092] This embodiment provides a separation and purification device system for coal-based mixed alcohols. The difference from Example 1 is that the number of baffles in the vacuum distillation tower 1 is adjusted to 50; the number of chromatographic columns 13 arranged in parallel with the sequential simulated moving bed 11 is adjusted to 12; the material filled in the chromatographic column 13 is replaced with resin; the number of baffles in the ethylene glycol dehydration tower 14 is adjusted to 50; the number of baffles in the 1,2-butanediol dehydration tower 15 is adjusted to 50, and the rest are the same as Example 1.

[0093] Example 4

[0094] This embodiment provides a separation and purification device system for coal-based mixed alcohols. The difference from Example 1 is that, except for replacing the sequential simulated moving bed 11 with a common simulated moving bed, the rest is the same as Example 1.

[0095] Example 5

[0096] This embodiment provides a separation and purification device system for coal-based mixed alcohols. The difference from Example 1 is that, except for adjusting the number of the chromatographic columns 13 to 4, the rest is the same as Example 1.

[0097] Example 6

[0098] This embodiment provides a separation and purification device system for coal-based mixed alcohols. The difference from Example 1 is that, except for adjusting the number of the chromatographic columns 13 to 16, the rest is the same as Example 1.

[0099] Comparative Example 1

[0100] This comparative example provides a separation and purification device for coal-based mixed alcohols, wherein the separation and purification device adopts the sequential simulated moving bed disclosed in CN112979419A.

[0101] Application Example 1

[0102] This application example provides a method for separating coal-based mixed alcohols. The separation method is performed using the separation and refining device system provided in Example 1. The separation method includes the following steps:

[0103] (1) subjecting the coal-based mixed alcohol to vacuum distillation at 25 kPa, wherein the bottom temperature of the vacuum distillation tower is 110° C., the top temperature is 40° C., and the reflux ratio is 10:1; obtaining a top extraction component, a bottom extraction component, and polyester-grade ethylene glycol;

[0104] The coal-based mixed alcohol is derived from byproducts of a coal-to-ethylene glycol reaction process; the coal-based mixed alcohol comprises ethylene glycol, 1,2-butanediol, and ultrapure water, wherein the mass percentage of ethylene glycol is 40wt% and the mass percentage of 1,2-butanediol is 20wt%; the top-extracted component comprises 40wt% ultrapure water, 30wt% ethylene glycol, and 30wt% 1,2-butanediol; the bottom-extracted component comprises 98wt% ethylene glycol; and the polyester-grade ethylene glycol contains 99.98wt% ethylene glycol.

[0105] (2) condensing the top extraction component obtained in step (1), partially refluxing the obtained condensate for vacuum distillation, and partially performing adsorption separation, wherein ultrapure water is added during the adsorption separation, and the operating temperature of the adsorption separation is 50° C. and the operating pressure is normal pressure, to obtain a raffinate and an extract; partially reboiling the bottom extraction component obtained in step (1) and returning it for vacuum distillation, and partially extracting it to obtain ethylene glycol;

[0106] (3) The extract obtained in step (2) is subjected to a first ultrapure water removal treatment at an operating pressure of 30 kPa, a bottom temperature of the 1,2-butanediol dehydration tower of 100°C, a top temperature of 40°C, and a reflux ratio of 3:1, to obtain ultrapure water with a mass percentage of 99.9 wt% and 1,2-butanediol with a mass percentage of 98 wt%, and the obtained ultrapure water is reused in the said adsorption separation treatment; the obtained raffinate is subjected to a second ultrapure water removal treatment at an operating pressure of 30 kPa, a bottom temperature of the ethylene glycol dehydration tower of 100°C, a top temperature of 40°C, and a reflux ratio of 3:1, to obtain ultrapure water with a mass percentage of 99.9 wt% and ethylene glycol with a mass percentage of 98 wt%, and the obtained ultrapure water is reused in the said adsorption separation treatment, and the obtained ethylene glycol is returned for vacuum distillation treatment.

[0107] In this application example, the single-pass yields of the obtained ethylene glycol and 1,2-butanediol both reached 99%, the purity of the obtained polyester-grade ethylene glycol was 99.98wt%, the purity of ethylene glycol was 98wt%, and the purity of 1,2-butanediol was 99wt%. The APHA color of the polyester-grade ethylene glycol was below 10, and the water content was below 1000ppm.

[0108] Application Example 2

[0109] This application example provides a method for separating coal-based mixed alcohols. The separation method is performed using the separation and refining device system provided in Example 1. The separation method includes the following steps:

[0110] (1) subjecting the coal-based mixed alcohol to vacuum distillation at 5 kPa, wherein the bottom temperature of the vacuum distillation tower is 70° C., the top temperature is 20° C., and the reflux ratio is 2:1; obtaining a top extraction component, a bottom extraction component, and polyester-grade ethylene glycol;

[0111] The coal-based mixed alcohol is derived from byproducts of a coal-to-ethylene glycol reaction process; the coal-based mixed alcohol comprises ethylene glycol, 1,2-butanediol, and ultrapure water, wherein the mass percentage of ethylene glycol is 35wt% and the mass percentage of 1,2-butanediol is 15wt%; the top-extracted component comprises 30wt% ultrapure water, 35wt% ethylene glycol, and 35wt% 1,2-butanediol; the bottom-extracted component comprises 97wt% ethylene glycol; and the polyester-grade ethylene glycol contains 99.95wt% ethylene glycol.

[0112] (2) condensing the top extraction component obtained in step (1), returning part of the obtained condensate to undergo vacuum distillation treatment, and subjecting part of the obtained condensate to adsorption separation treatment, wherein ultrapure water is added during the adsorption separation treatment, and the operating temperature of the adsorption separation treatment is 40° C. and the operating pressure is normal pressure, to obtain a raffinate and an extract; and returning part of the bottom extraction component obtained in step (1) to undergo vacuum distillation treatment after reboil treatment, and extracting part of the condensate to obtain ethylene glycol;

[0113] (3) The extract obtained in step (2) is subjected to a first ultrapure water removal treatment at an operating pressure of 5 kPa, a bottom temperature of the 1,2-butanediol dehydration tower of 70°C, a top temperature of 20°C, and a reflux ratio of 1:1, to obtain ultrapure water with a mass percentage of 99.9 wt% and 1,2-butanediol with a mass percentage of 98 wt%, and the obtained ultrapure water is reused in the said adsorption separation treatment; the obtained raffinate is subjected to a second ultrapure water removal treatment at an operating pressure of 5 kPa, a bottom temperature of the ethylene glycol dehydration tower of 70°C, a top temperature of 20°C, and a reflux ratio of 1:1, to obtain ultrapure water with a mass percentage of 99.9 wt% and ethylene glycol with a mass percentage of 96 wt%, and the obtained ultrapure water is reused in the said adsorption separation treatment, and the obtained ethylene glycol is returned for vacuum distillation treatment.

[0114] In this application example, the single-pass yields of the obtained ethylene glycol and 1,2-butanediol both reached 98.5%, the purity of the obtained polyester-grade ethylene glycol was 99.95wt%, the purity of ethylene glycol was 97wt%, and the purity of 1,2-butanediol was 98.8wt%. The APHA color of the polyester-grade ethylene glycol was below 10, and the water content was below 1000ppm.

[0115] Application Example 3

[0116] This application example provides a method for separating coal-based mixed alcohols. The separation method is performed using the separation and refining device system provided in Example 1. The separation method includes the following steps:

[0117] (1) subjecting the coal-based mixed alcohol to vacuum distillation at 50 kPa, wherein the bottom temperature of the vacuum distillation tower is 140° C., the top temperature is 80° C., and the reflux ratio is 25:1; obtaining a top-end produced component, a bottom-end produced component, and polyester-grade ethylene glycol;

[0118] The coal-based mixed alcohol is derived from byproducts of a coal-to-ethylene glycol reaction process; the coal-based mixed alcohol comprises ethylene glycol, 1,2-butanediol, and ultrapure water, wherein the mass percentage of ethylene glycol is 45wt% and the mass percentage of 1,2-butanediol is 25wt%; the top-extracted component comprises 50wt% ultrapure water, 25wt% ethylene glycol, and 25wt% 1,2-butanediol; the bottom-extracted component comprises 96wt% ethylene glycol; and the polyester-grade ethylene glycol contains 99.93wt% ethylene glycol.

[0119] (2) condensing the top extraction component obtained in step (1), partially refluxing the obtained condensate for vacuum distillation, and partially performing adsorption separation treatment, wherein ultrapure water is added during the adsorption separation treatment, and the operating temperature of the adsorption separation treatment is 70° C. and the operating pressure is normal pressure, to obtain a raffinate and an extract; partially reboiling the bottom extraction component obtained in step (1) and returning it for vacuum distillation treatment, and partially extracting it to obtain ethylene glycol;

[0120] (3) The extract obtained in step (2) is subjected to a first ultrapure water removal treatment at an operating pressure of 50 kPa, a bottom temperature of the 1,2-butanediol dehydration tower of 140°C, a top temperature of 80°C, and a reflux ratio of 5:1, to obtain ultrapure water with a mass percentage of 99.9 wt% and 1,2-butanediol with a mass percentage of 98.5 wt%, and the obtained ultrapure water is reused in the said adsorption separation treatment; the obtained raffinate is subjected to a second ultrapure water removal treatment at an operating pressure of 50 kPa, a bottom temperature of the ethylene glycol dehydration tower of 140°C, a top temperature of 80°C, and a reflux ratio of 5:1, to obtain ultrapure water with a mass percentage of 99.9 wt% and ethylene glycol with a mass percentage of 95 wt%, and the obtained ultrapure water is reused in the said adsorption separation treatment, and the obtained ethylene glycol is returned for vacuum distillation treatment.

[0121] In this application example, the single-pass yields of the obtained ethylene glycol and 1,2-butanediol both reached 98%, the purity of the obtained polyester-grade ethylene glycol was 99.93wt%, the purity of ethylene glycol was 96wt%, and the purity of 1,2-butanediol was 98.3wt%. The APHA color of the polyester-grade ethylene glycol was below 10, and the water content was below 1000ppm.

[0122] Application Example 4

[0123] This application example provides a method for separating coal-based mixed alcohols. The difference from application example 1 is that, except for adjusting the bottom temperature of the vacuum distillation tower in step (1) to 160°C, the rest is the same as example 1.

[0124] In this application example, due to the increase in the bottom temperature of the vacuum distillation tower, the single-pass yield of the obtained ethylene glycol and 1,2-butanediol is 92%, the purity of the obtained polyester-grade ethylene glycol is 99.98wt%, the purity of ethylene glycol is 92wt%, the purity of 1,2-butanediol is 95wt%, the color APHA of the polyester-grade ethylene glycol is 5, and the water content is less than 200ppm.

[0125] Application Example 5

[0126] This application example provides a method for separating coal-based mixed alcohols. The difference from application example 1 is that, except for adjusting the bottom temperature of the vacuum distillation tower in step (1) to 65°C, the rest is the same as example 1.

[0127] In this application example, due to the decrease in the bottom temperature of the vacuum distillation tower, the single-pass yield of the obtained ethylene glycol and 1,2-butanediol is 90%, the purity of the obtained polyester-grade ethylene glycol is 98.55wt%, the purity of ethylene glycol is 97.6wt%, the purity of 1,2-butanediol is 96.5wt%, the color APHA of the polyester-grade ethylene glycol is 20, and the water content is more than 4000ppm.

[0128] Application Example 6

[0129] This application example provides a method for separating coal-based mixed alcohols. The difference from application example 1 is that, except for adjusting the operating temperature of the adsorption separation treatment in step (2) to 80°C, the rest is the same as example 1.

[0130] In this application example, due to the increase in the adsorption separation treatment temperature, the single-pass yield of the obtained ethylene glycol and 1,2-butanediol is 98%, the purity of the obtained polyester-grade ethylene glycol is 99.9wt%, the purity of ethylene glycol is 95.5wt%, the purity of 1,2-butanediol is 92wt%, the color APHA of the polyester-grade ethylene glycol is 10, and the water content is below 1000ppm.

[0131] Application Example 7

[0132] This application example provides a method for separating coal-based mixed alcohols. The difference from application example 1 is that, except for adjusting the operating temperature of the adsorption separation treatment in step (2) to 25°C, the rest is the same as example 1.

[0133] In this application example, due to the reduction in the adsorption separation treatment temperature, the single-pass yield of the obtained ethylene glycol and 1,2-butanediol is 90%, the purity of the obtained polyester-grade ethylene glycol is 99.9wt%, the purity of ethylene glycol is 95wt%, the purity of 1,2-butanediol is 75wt%, the color APHA of the polyester-grade ethylene glycol is 10, and the water content is less than 1000ppm.

[0134] Application Example 8

[0135] This application example provides a method for separating coal-based mixed alcohols. The separation method is performed using the separation and refining device system provided in Example 2. The steps of the separation method are the same as those in Example 1.

[0136] In this application example, the single-pass yield of the obtained ethylene glycol and 1,2-butanediol is 98%, the purity of the obtained polyester-grade ethylene glycol is 99.98wt%, the purity of ethylene glycol is 99wt%, the purity of 1,2-butanediol is 98wt%, the color APHA of the polyester-grade ethylene glycol is 10, and the water content is less than 1000ppm.

[0137] Application Example 9

[0138] This application example provides a method for separating coal-based mixed alcohols. The separation method is performed using the separation and refining device system provided in Example 3. The steps of the separation method are the same as those in Example 1.

[0139] In this application example, the single-pass yield of the obtained ethylene glycol and 1,2-butanediol is 97.5%, the purity of the obtained polyester-grade ethylene glycol is 99.92wt%, the purity of ethylene glycol is 96wt%, the purity of 1,2-butanediol is 98wt%, the color APHA of the polyester-grade ethylene glycol is 10, and the water content is less than 1000ppm.

[0140] Application Example 10

[0141] This application example provides a method for separating coal-based mixed alcohols. The separation method is performed using the separation and refining device system provided in Example 4. The steps of the separation method are the same as those in Example 1.

[0142] In this application example, due to the use of a conventional simulated moving bed for adsorption separation treatment, the single-pass yield of the obtained ethylene glycol and 1,2-butanediol is only 92%, the purity of the obtained polyester-grade ethylene glycol is 99.2wt%, the purity of ethylene glycol is 92wt%, the purity of 1,2-butanediol is 90wt%, the color APHA of the polyester-grade ethylene glycol is 20, and the water content is below 3000ppm.

[0143] Application Example 11

[0144] This application example provides a method for separating coal-based mixed alcohols. The separation method is performed using the separation and refining device system provided in Example 5. The steps of the separation method are the same as those in Example 1.

[0145] In this application example, since the number of chromatographic columns in the sequential simulated moving bed is too low, the separation effect of ethylene glycol and 1,2-butanediol is reduced, and the single-pass yield of ethylene glycol and 1,2-butanediol is only 85%. The purity of the obtained polyester-grade ethylene glycol is 98.8wt%, the purity of ethylene glycol is 90wt%, and the purity of 1,2-butanediol is 68wt%. The color of the polyester-grade ethylene glycol is APHA 20, and the water content is more than 12000ppm.

[0146] Application Example 12

[0147] This application example provides a method for separating coal-based mixed alcohols. The separation method is performed using the separation and refining device system provided in Example 6. The steps of the separation method are the same as those in Example 1.

[0148] In this application example, due to the large number of chromatographic columns in the sequential simulated moving bed, ethylene glycol and 1,2-butanediol were difficult to extract. The single-pass yield of ethylene glycol and 1,2-butanediol was only 88%. The purity of the polyester-grade ethylene glycol was 99.92 wt%, the purity of ethylene glycol was 99 wt%, and the purity of 1,2-butanediol was 86 wt%. The APHA color of the polyester-grade ethylene glycol was 10, and the water content was below 1000 ppm.

[0149] Comparative Application Example 1

[0150] This comparative application example provides a method for separating coal-based mixed alcohols. The separation method is performed using the separation and refining device system provided in Comparative Example 1. The steps of the separation method are performed using the separation method disclosed in CN 112979419A.

[0151] In this comparative application example, since ethylene glycol and 1,2-butanediol were only separated by sequential simulated moving bed separation without subsequent treatment, the purity of ethylene glycol and 1,2-butanediol was not high and the solvent consumption was large. The single-pass yield of the obtained ethylene glycol and 1,2-butanediol was only 94%, the purity of the obtained polyester-grade ethylene glycol was 98.2wt%, the purity of ethylene glycol was 98wt%, and the purity of 1,2-butanediol was 98wt%. The APHA color of the polyester-grade ethylene glycol was 20, and the water content was more than 18,000 ppm.

[0152] In summary, the separation and purification device system of the coal-based mixed alcohol provided by the present invention adopts a vacuum distillation and adsorption separation coupling process to efficiently separate ethylene glycol and 1,2-butanediol. By adopting a suitable separation and purification device for purification, distillation, adsorption separation and eluent removal are carried out in sequence to achieve efficient separation of ethylene glycol and 1,2-butanediol. The obtained ethylene glycol and 1,2-butanediol products have high purity and yield. The method is simple to operate, highly safe, has low energy consumption, saves energy, and has a wide range of applications.

[0153] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A separation and purification device system for coal-based mixed alcohol, characterized in that: The separation and refining device system includes a vacuum distillation unit, a continuous adsorption separation unit and an eluent removal unit connected in sequence along the material flow direction. The eluent discharged from the eluent removal unit is recycled back to the continuous adsorption separation unit, and the ethylene glycol discharged from the eluent removal unit is recycled back to the vacuum distillation unit.

2. The separation and purification device system according to claim 1, characterized in that: The vacuum distillation unit includes a vacuum distillation device, the top of the vacuum distillation device is connected to a cooling component, the bottom is connected to a heating component, and the side walls are respectively connected to a feeding component and a polyester-grade ethylene glycol storage device; Preferably, the number of baffles in the vacuum distillation device is 20 to 50; Preferably, the cooling assembly comprises a condenser, a top reflux device, and a reflux pump connected in sequence along the material flow direction, the inlet of the condenser is connected to the top outlet of the vacuum distillation device, the outlet of the reflux pump is connected to the reflux port of the vacuum distillation device, and the outlet of the top reflux device is also connected to the continuous adsorption separation unit; Preferably, the heating assembly includes a circulation pump, the inlet of the circulation pump is connected to the bottom outlet of the vacuum distillation device, the outlet of the circulation pump is connected to a reboiler and an ethylene glycol storage device respectively, and the material discharged from the reboiler is returned to the vacuum distillation device; Preferably, the feed assembly includes a first feed pump and a second feed pump, the outlet of the first feed pump is connected to the first feed port of the vacuum distillation device, the outlet of the second feed pump is connected to the second feed port of the vacuum distillation device, and the inlet of the second feed pump is connected to the eluent removal unit.

3. The separation and purification device system according to claim 2, characterized in that: The continuous adsorption separation unit includes a sequential simulated moving bed and a preheater connected to the feed inlet of the sequential simulated moving bed, and the preheater is connected to the outlet of the top reflux device; Preferably, the sequential simulated moving bed is provided with 6 to 12 chromatographic columns in parallel; Preferably, the chromatographic column is filled with any one of resin, molecular sieve or activated carbon; Preferably, a top control valve is provided at the top of the chromatographic column, and the top control valve is respectively connected to the feed pipeline and the eluent pipeline of the sequential simulated moving bed; a bottom control valve is provided at the bottom end of the chromatographic column, and the bottom control valve is respectively connected to the raffinate discharge pipeline and the extract discharge pipeline of the sequential simulated moving bed; a pipeline control valve is provided between the chromatographic columns, and the pipeline control valve is connected to the chromatographic columns of the sequential simulated moving bed.

4. The separation and purification device system according to claim 3, characterized in that: The eluent removal unit includes an ethylene glycol dehydration device, a 1,2-butanediol dehydration device, a 1,2-butanediol storage device and an eluent storage device; the feed port of the ethylene glycol dehydration device is connected to the raffinate discharge port of the sequential simulated moving bed, the top outlet of the ethylene glycol dehydration device is connected to the eluent storage device, and the bottom outlet of the ethylene glycol dehydration device is connected to the inlet of the second feed pump; the feed port of the 1,2-butanediol dehydration device is connected to the extract discharge port of the sequential simulated moving bed, the top outlet of the 1,2-butanediol dehydration device is connected to the eluent storage device, and the bottom outlet of the 1,2-butanediol dehydration device is connected to the 1,2-butanediol storage device; the eluent storage device is connected to the sequential simulated moving bed via an eluent delivery pump; Preferably, the number of baffles in the ethylene glycol dehydration device is 25 to 50; Preferably, the number of partitions in the 1,2-butanediol dehydration device is 30 to 50.

5. A method for separating coal-based mixed alcohols, characterized in that: The separation method is carried out by the separation and purification device system according to any one of claims 1 to 4, and the separation method comprises the following steps: (1) subjecting the coal-based mixed alcohol to vacuum distillation to obtain a top-extracted component, a bottom-extracted component, and polyester-grade ethylene glycol; (2) subjecting the top extracted component obtained in step (1) to an adsorption separation treatment, wherein an eluent is added during the adsorption separation treatment to obtain a raffinate and an extract; a portion of the bottom extracted component obtained in step (1) is reboiled and then returned to a vacuum distillation treatment, and a portion is extracted to obtain ethylene glycol; (3) The extract obtained in step (2) is subjected to a first eluent removal treatment to obtain 1,2-butanediol; the obtained raffinate is subjected to a second eluent removal treatment and then returned for vacuum distillation.

6. The separation method according to claim 5, characterized in that The source of the coal-based mixed alcohol in step (1) includes by-products of a coal-to-ethylene glycol reaction process; Preferably, the coal-based mixed alcohol in step (1) comprises ethylene glycol, 1,2-butanediol and an eluent; Preferably, the mass percentage of ethylene glycol in the coal-based mixed alcohol is 35-45 wt%, and the mass percentage of 1,2-butanediol is 15-25 wt%.

7. The separation method according to claim 5 or 6, characterized in that The operating pressure of the vacuum distillation treatment in step (1) is 5 to 50 kPa; Preferably, the bottom temperature of the vacuum distillation device in step (1) is 70-140° C., and the top temperature is 20-80° C.; Preferably, the reflux ratio of the vacuum distillation treatment in step (1) is (2-25):1; Preferably, the top-extracted components in step (1) include 30-50 wt% of an eluent, 25-35 wt% of ethylene glycol, and 25-35 wt% of 1,2-butanediol; Preferably, the bottom extracted component in step (1) comprises 95-98 wt% of ethylene glycol; Preferably, the polyester-grade ethylene glycol in step (1) contains >99.9 wt% of ethylene glycol.

8. The separation method according to any one of claims 5 to 7, characterized in that Before the adsorption separation treatment in step (2), the top extracted component is condensed, and part of the obtained condensate is refluxed for vacuum distillation treatment, and part is subjected to adsorption separation treatment; Preferably, the eluent in step (2) comprises any one of ultrapure water, ethanol aqueous solution or methanol, or a combination of at least two thereof; Preferably, the volume ratio of ethanol to water in the ethanol aqueous solution is 1:(1-9); Preferably, the operating temperature of the adsorption separation treatment in step (2) is 40-70° C., and the operating pressure is normal pressure.

9. The separation method according to any one of claims 5 to 8, characterized in that The operating pressure of the first eluent removal treatment in step (3) is 5 to 50 kPa; Preferably, in step (3), the temperature at the bottom of the 1,2-butanediol dehydration device where the first eluent is removed is 70-140° C., and the temperature at the top is 20-80° C.; Preferably, the reflux ratio of the first eluent removal treatment in step (3) is (1-5):1; Preferably, after the first eluent is removed in step (3), an eluent with a mass percentage of ≥99.9wt% and a 1,2-butanediol with a mass percentage of ≥98wt% are obtained, and the obtained eluent is reused in the adsorption separation treatment.

10. The separation method according to any one of claims 5 to 9, characterized in that The operating pressure of the second eluent removal treatment in step (3) is 5 to 50 kPa; Preferably, the bottom temperature of the glycol dehydration device where the second eluent removal treatment is carried out in step (3) is 70-140° C., and the top temperature is 20-80° C.; Preferably, the reflux ratio of the second eluent removal treatment in step (3) is (1-5):1; Preferably, after the second eluent is removed in step (3), an eluent with a mass percentage of ≥99.9wt% and an ethylene glycol with a mass percentage of ≥95wt% are obtained, and the obtained eluent is reused in the adsorption separation treatment, and the obtained ethylene glycol is returned for vacuum distillation treatment.

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