Device and method for separating ethylene glycol and 1, 2-butanediol

Abstract

The invention discloses a separation device of ethylene glycol and 1, 2-butanediol, which comprises an extraction tower, an azeotropic rectifying tower and a water scrubber, the top of the extraction tower is communicated with the azeotropic rectifying tower through a pipeline, the top of the azeotropic rectifying tower is sequentially communicated with a tower top condenser and a tower top phase separation tank through pipelines, and the tower top phase separation tank is communicated with a tower top condenser through a pipeline. A light phase flow outlet and a heavy phase flow outlet are formed in the tower top phase splitting tank, the light phase flow outlet is communicated with the top of the azeotropic rectifying tower through a pipeline, the bottom of the azeotropic rectifying tower is communicated with the water washing tower through a first pipeline, and a cooler is arranged on the first pipeline. The invention also discloses a separation method of the separation device for ethylene glycol and 1, 2-butanediol. Continuous large-scale production can be achieved, the selected solvent has the advantages of being high in selectivity and easy to separate from ethylene glycol, and the production cost of mixed alcohol separation is expected to be greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of azeotropic system separation, in particular to a separation device and a separation method for ethylene glycol and 1,2-butanediol. Background Art

[0002] Ethylene glycol is an important chemical solvent and raw material for the production of chemical products. It is mainly used in the preparation of polyester fibers, antifreeze and surfactants. my country has a large production capacity of ethylene glycol using coal as raw material. In the process of synthesizing ethylene glycol, a large amount of 1,2-butanediol by-product (about 15% of the total mass) is also produced. Since the boiling points of ethylene glycol and 1,2-butanediol are close and can form an azeotropic system, conventional vacuum distillation will produce a mixture containing about 45-50% 1,2-butanediol close to the azeotropic composition and cannot be separated. In order to separate the mixture, a special method is required.

[0003] At present, the main technical means in industry are azeotropic distillation, reactive distillation and adsorption separation. U.S. Patents US4935102 and US4966658 disclose a separation method using azeotropic distillation, which uses a variety of ethers, ketones or aromatic compounds as entrainers to azeotropically separate ethylene glycol, and the relative volatility between the two alcohols can be increased from 1.1 to about 1.5. Although this method can enhance the separation efficiency of the two, a large reflux ratio is required during distillation, resulting in high energy consumption. Chinese patent CN201711477528.8 uses dimethyl oxalate as an entrainer to azeotropically separate 1,2-butanediol, and also has similar characteristics as mentioned above. U.S. Patent US6548681 reports a production method using reactive distillation, which is to react mixed alcohols into 2-methyl-1,3-dioxolane and 2,4-dimethyl-1,3-dioxolane under the condition of an acidic catalyst, and then separate the reaction products by distillation, and then hydrolyze them separately to obtain the target products after separation. The process of this method is very complicated, resulting in high production costs. In addition, although the adsorption method is also highly efficient, its processing capacity is low. Considering the complexity of adsorbent regeneration, this method is not suitable for large-scale production processes. Summary of the invention

[0004] The object of the present invention is to provide a separation device for ethylene glycol and 1,2-butanediol.

[0005] The invention also provides a separation method of a separation device for separating ethylene glycol and 1,2-butanediol.

[0006] The innovation of the present invention is that it can realize continuous large-scale production, and the selected solvent has the characteristics of high selectivity and easy separation from ethylene glycol, which is expected to greatly reduce the production cost of mixed alcohol separation.

[0007] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is:

[0008] A separation device for ethylene glycol and 1,2-butanediol, characterized in that it comprises an extraction tower, an azeotropic distillation tower and a water washing tower, wherein the top of the extraction tower is an upper separation section of the extraction tower, the bottom is a lower separation tank of the extraction tower, and the middle section is an extraction section; the azeotropic distillation tower comprises a distillation section and a stripping section from top to bottom, and a tower top condenser and a tower top phase separation tank are arranged at the top of the azeotropic distillation tower; the top of the water washing tower is an upper separation section of the water washing tower, the bottom is a lower separation tank of the water washing tower, and the middle section is a water washing section; the top of the extraction tower is connected with the azeotropic distillation tower through a pipeline, the top of the azeotropic distillation tower is connected with the tower top condenser and the tower top phase separation tank in sequence through a pipeline, a light phase flow outlet and a heavy phase flow outlet are arranged on the tower top phase separation tank, the light phase flow outlet and the top of the azeotropic distillation tower are connected through a pipeline, the bottom of the azeotropic distillation tower is connected with the water washing tower through a No. 1 pipeline, and a cooler is arranged on the No. 1 pipeline.

[0009] Furthermore, a kettle reboiler is provided at the bottom of the azeotropic distillation tower, a vaporization port of the kettle reboiler is connected to the bottom of the kettle reboiler through a pipeline, and a liquid outflow port of the kettle reboiler is connected to a No. 1 pipeline.

[0010] Furthermore, a heat exchanger is also provided on the No. 1 pipeline.

[0011] Furthermore, the extraction section of the extraction tower is equipped with a plurality of sieve plates or fillers; the distillation section and stripping section of the azeotropic distillation tower are equipped with a plurality of sieve plates, floating valve plates or fillers; and the washing section of the water washing tower is equipped with a plurality of sieve plates or fillers.

[0012] A separation method of a separation device for ethylene glycol and 1,2-butanediol comprises the following steps:

[0013] (1) A mixture of ethylene glycol and 1,2-butanediol containing 45-50% (wt%) 1,2-butanediol is heated to 70-110°C and enters the extraction tower from the top. The solvent is heated to

[0014] 70~110℃ enters the extraction tower from the bottom, the solvent is one of amyl butyrate or butyl valerate, the two are extracted by countercurrent to form a liquid-liquid two-phase interface in the separation tank under the extraction tower,

[0015] The heavy phase is the raffinate phase which is discharged from the bottom of the extraction tower, and the extraction phase is obtained from the top of the extraction tower. After being purified by the separation section on the extraction tower, the purified extraction phase is obtained and enters the azeotropic distillation tower;

[0016] (2) The purified extract phase is divided into two parts in the azeotropic distillation tower. The gaseous azeotrope at the top of the azeotropic distillation tower is condensed by the top condenser at the top of the azeotropic distillation tower to obtain liquid-liquid two-phases which enter the top phase separation tank for automatic separation. The light phase material returns to the top of the azeotropic distillation tower, and the heavy phase material continuously leaves the top phase separation tank.

[0017] (3) The bottom kettle liquid of the azeotropic distillation tower is cooled to room temperature by a cooler and then enters the bottom of the water scrubber. Room temperature water is added from the top of the water scrubber. The two are washed with countercurrent water to form a liquid-liquid two-phase interface in the separation tank below the water scrubber. The heavy phase is the washing phase and is discharged from the bottom of the water scrubber. The washing residual phase obtained at the top of the tower is purified by the separation section on the water scrubber and continuously discharged from the top of the tower.

[0018] Furthermore, the solvent is heat exchanged with the bottom kettle liquid of the azeotropic distillation tower before entering the extraction tower. After the heat exchange, the solvent is heated to 70-110°C and enters the extraction tower from the bottom of the extraction tower. The bottom kettle liquid of the azeotropic distillation tower is first fully heat exchanged and then cooled to room temperature by a cooler before entering the bottom of the water washing tower.

[0019] Furthermore, a bottom reboiler is provided at the bottom of the azeotropic distillation tower, and the bottom liquid of the azeotropic distillation tower is partially vaporized by the bottom reboiler, and the gas returns to the bottom of the azeotropic distillation tower, and the remaining liquid is transported to the heat exchanger.

[0020] Furthermore, the mixture of ethylene glycol and 1,2-butanediol containing 45-50% (wt%) of 1,2-butanediol is heated to 70-110° C. by a raw material heater and enters the extraction tower from the top of the extraction tower.

[0021] Furthermore, the mass of the solvent is 3 to 4.5 times the mass of the mixture of ethylene glycol and 1,2-butanediol containing 45 to 50% (wt%) of 1,2-butanediol; the water consumption of the water washing tower is 0.3 to 0.5 times the mass of the mixture of ethylene glycol and 1,2-butanediol containing 45 to 50% (wt%) of 1,2-butanediol.

[0022] Furthermore, the pressure at the top of the azeotropic distillation tower is -0.08 to -0.095 MPa.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention adopts a continuous extraction combined with azeotropic distillation process, which is technically mature and reliable and can meet the needs of large-scale production.

[0025] 2. The present invention adopts extraction and stripping (water washing) processes, which greatly reduces the energy-consuming means of gasification, condensation, etc. required for distillation separation, which is beneficial to reducing energy consumption.

[0026] 3. The present invention adopts a continuous countercurrent extraction and stripping process, which has the characteristics of high automation, easy operation and high separation efficiency.

[0027] 4. The present invention achieves high selectivity and high extraction rate simultaneously by adjusting the extraction temperature.

[0028] 5. The present invention reasonably achieves the purpose of efficient separation of ethylene glycol and 1,2-butanediol through liquid-liquid phase distribution. Calculations show that the obtained raffinate phase and washing phase are treated by simple distillation respectively, and the product purity of ethylene glycol and 1,2-butanediol can reach more than 99.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the structure of Example 4. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings.

[0031] Embodiment 1: A separation device for ethylene glycol and 1,2-butanediol comprises an extraction tower 1, an azeotropic distillation tower 2 and a water washing tower 3. The top of the extraction tower 1 is an upper separation section 1.1 of the extraction tower, the bottom is a lower separation tank 1.2 of the extraction tower, and the middle section is an extraction section 1.3; the azeotropic distillation tower 2 comprises, from top to bottom, a distillation section 2.1 and a stripping section 2.2, and the top of the azeotropic distillation tower 2 is provided with a top condenser 4 and a top phase separation tank 5; the top of the water washing tower 3 is an upper separation section 3.1 of the water washing tower, the bottom is a lower separation tank 3.2 of the water washing tower, and the middle section is a water washing section 3.3; the extraction section 1.3 of the extraction tower 1 is equipped with a plurality of sieve plates or fillers; the distillation section 2.1 and the stripping section 2.2 of the azeotropic distillation tower 2 are equipped with a plurality of sieve plates, floating valve plates or fillers; the water washing section 3.3 of the water washing tower 3 is equipped with a plurality of sieve plates or fillers. The top of the extraction tower 1 is connected to the azeotropic distillation tower 2 through a pipeline, and the top of the azeotropic distillation tower 2 is connected to the top condenser 4 and the top phase separation tank 5 in sequence through a pipeline. The top phase separation tank is provided with a light phase flow outlet and a heavy phase flow outlet, and the light phase flow outlet and the top of the azeotropic distillation tower 2 are connected through a pipeline. The bottom of the azeotropic distillation tower 2 is connected to the water washing tower 3 through a No. 1 pipeline 6, and a cooler 7 is provided on the No. 1 pipeline 6, and a heat exchanger 9 is also provided on the No. 1 pipeline 6.

[0032] A tower bottom reboiler 8 is provided at the bottom of the azeotropic distillation tower 2 , a vaporization port of the tower bottom reboiler 8 is connected to the bottom of the tower bottom reboiler 8 through a pipeline, and a liquid outflow port of the tower bottom reboiler 8 is connected to a No. 1 pipeline 6 .

[0033] Embodiment 2: A separation method of a separation device for ethylene glycol and 1,2-butanediol, comprising the following steps:

[0034] A mixture of ethylene glycol and 1,2-butanediol containing 45% (wt%) of 1,2-butanediol is heated to 70°C by a raw material heater 11 and enters the extraction tower 1 from the top. A solvent is heated to 70°C and enters the extraction tower 1 from the bottom. The solvent is one of amyl butyrate and butyl valerate. The mass of the solvent is 3 times the mass of the mixture of ethylene glycol and 1,2-butanediol containing 45% (wt%) of 1,2-butanediol. The two are subjected to countercurrent extraction to form a liquid-liquid two-phase interface in a separation tank 1.2 under the extraction tower. The heavy phase is the raffinate phase and is discharged from the bottom of the extraction tower 1. The extraction phase obtained at the top of the extraction tower 1 is purified by the separation section 1.1 on the extraction tower to obtain a purified extraction phase and enter the azeotropic distillation tower.

[0035] The purified extract phase is divided into two parts in the azeotropic distillation tower 2. The gaseous azeotrope at the top of the azeotropic distillation tower 2 is condensed by the top condenser 4 at the top of the azeotropic distillation tower 1 to obtain liquid-liquid two-phases which enter the top phase separation tank 5 for automatic separation. The light phase material returns to the top of the azeotropic distillation tower 2, and the heavy phase material continuously leaves the top phase separation tank 5. The pressure at the top of the azeotropic distillation tower 2 is -0.08 MPa.

[0036] The bottom kettle liquid of the azeotropic distillation tower 2 is cooled to room temperature by a cooler and then enters the bottom of the water washing tower 3. Room temperature water is added from the top of the water washing tower 3. The water consumption of the water washing tower 3 is 0.3 times the mass of the mixed material of ethylene glycol and 1,2-butanediol containing 45% (wt%) of 1,2-butanediol. The two are washed with countercurrent water to form a liquid-liquid two-phase interface in the separation tank 3.2 under the water washing tower. The heavy phase is the washing phase and is discharged from the bottom of the water washing tower 3. The washing residual phase obtained at the top of the tower is purified by the separation section 3.1 on the water washing tower and continuously discharged from the top of the tower.

[0037] The residual phase is a pure recovery solvent and can be returned to the extraction tower 1 for use; the raffinate phase is an ethylene glycol solution containing a small amount of 1,2-butanediol and solvent, which can be obtained from the top of the tower by vacuum distillation to obtain a mixed material with a higher concentration of 1,2-butanediol and returned to the raw material of the extraction tower 1, and pure ethylene glycol is obtained at the bottom of the tower; the washing phase is an aqueous solution of 1,2-butanediol containing a small amount of solvent, and the water and solvent are removed from the top by vacuum distillation, and the bottom of the tower is pure 1,2-butanediol.

[0038] The separation method of Example 2 is adopted, wherein the theoretical number of plates of the extraction tower 1 is 8; the theoretical number of plates of the distillation section of the azeotropic distillation tower 2 is 9, and the theoretical number of plates of the stripping section is 15; and the theoretical number of plates of the water washing tower 3 is 6.

[0039] The flow rate of the mixture of ethylene glycol and 1,2-butanediol containing 45% (wt%) of 1,2-butanediol is 1000 kg / h; the flow rate of water in the water washing tower is 400 kg / h.

[0040] The calculation results show that the raffinate flow rate of extraction tower 1 is 554.6 kg / h, containing 72.57% ethylene glycol, 20.83% 1,2-butanediol, 6.60% amyl butyrate, and the extraction rate of 1,2-butanediol is 76.9%.

[0041] The bottom flow rate of the azeotropic distillation tower 2 is 3537.5 kg / h, and contains 0.04% ethylene glycol, 10.64% 1,2-butanediol, and 89.32% amyl butyrate.

[0042] The washing phase flow rate of the water washing tower 3 is 811.8 kg / h, containing 0.17% ethylene glycol, 46.37% 1,2-butanediol, 5.80% amyl butyrate and 47.66% water.

[0043] Embodiment 3: A separation method of a separation device for ethylene glycol and 1,2-butanediol, comprising the following steps:

[0044] A mixed material of ethylene glycol and 1,2-butanediol containing 47% (wt%) of 1,2-butanediol is heated to 90° C. by a raw material heater 11 and enters the extraction tower 1 from the top. Before the solvent enters the extraction tower 1, it exchanges heat with the bottom kettle liquid of the azeotropic distillation tower 2 through a heat exchanger 9. After the heat exchange, the solvent is heated to 90° C. and enters the extraction tower 1 from the bottom. The solvent is one of amyl butyrate or butyl valerate. The mass of the solvent is 4 times the mass of the mixed material of ethylene glycol and 1,2-butanediol containing 47% (wt%) of 1,2-butanediol. The two are subjected to countercurrent extraction to form a liquid-liquid two-phase interface in the lower separation tank 1.2 of the extraction tower, wherein the heavy phase is the raffinate phase discharged from the bottom of the extraction tower 1, and the extraction phase obtained at the top of the extraction tower 1 is purified by the upper separation section 1.1 of the extraction tower to obtain a purified extraction phase that enters the azeotropic distillation tower;

[0045] The purified extract phase is divided into two parts in the azeotropic distillation tower 2. The gaseous azeotrope at the top of the azeotropic distillation tower 2 is condensed by the top condenser 4 at the top of the azeotropic distillation tower 1 to obtain liquid-liquid two-phases which enter the top phase separation tank 5 for automatic separation. The light phase material returns to the top of the azeotropic distillation tower 2, and the heavy phase material continuously leaves the top phase separation tank 5. The pressure at the top of the azeotropic distillation tower 2 is -0.09 MPa.

[0046] Before the solvent enters the extraction tower 1, it exchanges heat with the bottom kettle liquid of the azeotropic distillation tower 2 through the heat exchanger 9. After the heat exchange, the solvent is heated to 90°C and enters the extraction tower 1 from the bottom of the extraction tower 1. The bottom kettle liquid of the azeotropic distillation tower 2 is first fully heat-exchanged and then cooled to room temperature by the cooler 7 before entering the bottom of the water washing tower 3. Room-temperature water is added from the top of the water washing tower 3. The water consumption of the water washing tower 3 is 0.4 times the mass of the mixed material of ethylene glycol and 1,2-butanediol containing 47% (wt%) of 1,2-butanediol. The two are washed with countercurrent water to form a liquid-liquid two-phase interface in the lower separation tank 3.2 of the water washing tower, wherein the heavy phase is the washing phase and is discharged from the bottom of the water washing tower 3. The washing residual phase obtained at the top of the tower is purified by the upper separation section 3.1 of the water washing tower and continuously discharged from the top of the tower.

[0047] The separation method of Example 2 is adopted, wherein the theoretical number of plates of the extraction tower 1 is 6; the theoretical number of plates of the distillation section of the azeotropic distillation tower 2 is 15, and the theoretical number of plates of the stripping section is 9; and the theoretical number of plates of the water washing tower 3 is 6.

[0048] The flow rate of the mixture of ethylene glycol and 1,2-butanediol containing 45% (wt%) of 1,2-butanediol is 1000 kg / h, and the flow rate of water in the water washing tower is 300 kg / h.

[0049] The calculation results show that the raffinate flow rate of extraction tower 1 is 615.7 kg / h, containing 75.08% ethylene glycol, 18.93% 1,2-butanediol, 5.99% butyl valerate, and the extraction rate of 1,2-butanediol is 74.1%.

[0050] The bottom flow rate of the azeotropic distillation tower 2 is 4687.3 kg / h, and contains 0.03% ethylene glycol, 6.96% 1,2-butanediol, and 93.01% butyl valerate.

[0051] The washing phase flow rate of the water washing tower 3 is 650.3 kg / h, containing 0.22% ethylene glycol, 50.16% 1,2-butanediol, 6.27% butyl valerate and 43.35% water.

[0052] Embodiment 4: A separation method of a separation device for ethylene glycol and 1,2-butanediol, comprising the following steps:

[0053] A mixed material of ethylene glycol and 1,2-butanediol containing 50% (wt%) of 1,2-butanediol is heated to 110° C. by a raw material heater 11 and enters the extraction tower 1 from the top. Before the solvent enters the extraction tower 1, it exchanges heat with the bottom kettle liquid of the azeotropic distillation tower 2 through a heat exchanger 9. After the heat exchange, the solvent is heated to 110° C. and enters the extraction tower 1 from the bottom. The solvent is one of amyl butyrate or butyl valerate, and the mass of the solvent is 4.5 times the mass of the mixed material of ethylene glycol and 1,2-butanediol containing 50% (wt%) of 1,2-butanediol. The two are subjected to countercurrent extraction to form a liquid-liquid two-phase interface in a separation tank 1.2 under the extraction tower, wherein the heavy phase is the raffinate phase discharged from the bottom of the extraction tower 1, and the extraction phase obtained at the top of the extraction tower 1 is purified by the separation section 1.1 on the extraction tower to obtain a purified extraction phase that enters the azeotropic distillation tower;

[0054] The purified extract phase is divided into two parts in the azeotropic distillation tower 2. The gaseous azeotrope at the top of the azeotropic distillation tower 2 is condensed by the top condenser 4 at the top of the azeotropic distillation tower 1 to obtain liquid-liquid two-phases which enter the top phase separation tank 5 for automatic separation. The light phase material returns to the top of the azeotropic distillation tower 2, and the heavy phase material continuously leaves the top phase separation tank 5. The pressure at the top of the azeotropic distillation tower 2 is -0.095 MPa.

[0055] A bottom reboiler 8 is provided at the bottom of the azeotropic distillation tower 2. The bottom bottom liquid of the azeotropic distillation tower 2 is partially vaporized by the bottom reboiler 8, and the gas returns to the bottom of the azeotropic distillation tower 2. The remaining liquid is transported to the heat exchanger 9 for sufficient heat exchange and then cooled to room temperature by the cooler 7 before entering the bottom of the water washing tower 3. Room temperature water is added from the top of the water washing tower 3. The water consumption of the water washing tower 3 is 0.5 times the mass of the mixed material of ethylene glycol and 1,2-butanediol containing 0% (wt%) of 1,2-butanediol. The two are washed with countercurrent water to form a liquid-liquid two-phase interface in the lower separation tank 3.2 of the water washing tower, wherein the heavy phase is the washing phase and is discharged from the bottom of the water washing tower 3. The washing residual phase obtained at the top of the tower is purified by the upper separation section 3.1 of the water washing tower and continuously discharged from the top of the tower.

[0056] The separation method of Example 4 is adopted, wherein the theoretical plate number of the extraction tower 1 is 8; the theoretical plate number of the distillation section of the azeotropic distillation tower 2 is 15, and the theoretical plate number of the stripping section is 9; and the theoretical plate number of the water washing tower 3 is 4.

[0057] The flow rate of the mixture of ethylene glycol and 1,2-butanediol containing 45% (wt%) of 1,2-butanediol is 1000 kg / h; the flow rate of water in the water washing tower is 400 kg / h.

[0058] The calculation results show that the raffinate flow rate of extraction tower 1 is 555.6 kg / h, containing 71.92% ethylene glycol, 21.33% 1,2-butanediol, 6.75% butyl valerate, and the extraction rate of 1,2-butanediol is 76.3%.

[0059] The bottom flow rate of the azeotropic distillation tower 2 is 4733.3 kg / h, and contains 0.03% ethylene glycol, 7.89% 1,2-butanediol, and 92.08% butyl valerate.

[0060] The washing phase flow rate of the water washing tower 3 is 803.3 kg / h, containing 0.18% ethylene glycol, 46.47% 1,2-butanediol, 5.81% butyl valerate and 47.54% water.

[0061] The described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A separation device for ethylene glycol and 1,2-butanediol, characterized in that: It includes an extraction tower, an azeotropic distillation tower and a water washing tower. The top of the extraction tower is an upper separation section of the extraction tower, the bottom is a lower separation tank of the extraction tower, and the middle section is an extraction section. The azeotropic distillation tower includes a distillation section and a stripping section from top to bottom. The top of the azeotropic distillation tower is provided with a top condenser and a top phase separation tank. The top of the water washing tower is an upper separation section of the water washing tower, the bottom is a lower separation tank of the water washing tower, and the middle section is a water washing section. The top of the extraction tower is connected with the azeotropic distillation tower through a pipeline, and the top of the azeotropic distillation tower is connected with the top condenser and the top phase separation tank in sequence through a pipeline. A light phase flow outlet and a heavy phase flow outlet are provided on the top phase separation tank, and the light phase flow outlet is connected with the top of the azeotropic distillation tower through a pipeline. The bottom of the azeotropic distillation tower is connected with the water washing tower through a No. 1 pipeline, and a cooler is provided on the No. 1 pipeline.

2. The device for separating ethylene glycol and 1,2-butanediol according to claim 1, characterized in that: A tower bottom reboiler is provided at the bottom of the azeotropic distillation tower, a vaporization port of the tower bottom reboiler is connected to the bottom of the tower bottom reboiler through a pipeline, and a liquid outflow port of the tower bottom reboiler is connected to a No. 1 pipeline.

3. The separation device of ethylene glycol and 1,2-butanediol according to claim 1, characterized in that: The No. 1 pipeline is also provided with a heat exchanger.

4. The device for separating ethylene glycol and 1,2-butanediol according to claim 1, characterized in that: The extraction section of the extraction tower is equipped with a plurality of sieve plates or fillers; the distillation section and stripping section of the azeotropic distillation tower are equipped with a plurality of sieve plates, floating valve plates or fillers; and the washing section of the water washing tower is equipped with a plurality of sieve plates or fillers.

5. A separation method of the ethylene glycol and 1,2-butanediol separation device according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) A mixture of ethylene glycol and 1,2-butanediol containing 45-50% (wt%) of 1,2-butanediol is heated to 70-110°C and enters the extraction tower from the top. A solvent is heated to 70-110°C and enters the extraction tower from the bottom. The solvent is one of amyl butyrate or butyl valerate. The two are subjected to countercurrent extraction to form a liquid-liquid two-phase interface in the separation tank below the extraction tower. The heavy phase is the raffinate phase and is discharged from the bottom of the extraction tower. The extraction phase obtained at the top of the extraction tower is purified in the separation section of the extraction tower to obtain a purified extraction phase that enters the azeotropic distillation tower. (2) The purified extract phase is divided into two parts in the azeotropic distillation tower. The gaseous azeotrope at the top of the azeotropic distillation tower is condensed by the top condenser at the top of the azeotropic distillation tower to obtain liquid-liquid two-phases which enter the top phase separation tank for automatic separation. The light phase material returns to the top of the azeotropic distillation tower, and the heavy phase material continuously leaves the top phase separation tank. (3) The bottom kettle liquid of the azeotropic distillation tower is cooled to room temperature by a cooler and then enters the bottom of the water scrubber. Room temperature water is added from the top of the water scrubber. The two are washed with countercurrent water to form a liquid-liquid two-phase interface in the separation tank below the water scrubber. The heavy phase is the washing phase and is discharged from the bottom of the water scrubber. The washing residual phase obtained at the top of the tower is purified by the separation section on the water scrubber and continuously discharged from the top of the tower.

6. The separation method of the ethylene glycol and 1,2-butanediol separation device according to claim 5, characterized in that: Before the solvent enters the extraction tower, it exchanges heat with the bottom kettle liquid of the azeotropic distillation tower. After the heat exchange, the solvent is heated to 70-110°C and enters the extraction tower from the bottom of the extraction tower. The bottom kettle liquid of the azeotropic distillation tower is first fully heat exchanged and then cooled to room temperature by a cooler before entering the bottom of the water washing tower.

7. The separation method of the ethylene glycol and 1,2-butanediol separation device according to claim 6, characterized in that: A bottom reboiler is provided at the bottom of the azeotropic distillation tower. The bottom liquid of the azeotropic distillation tower is partially vaporized by the bottom reboiler, and the gas returns to the bottom of the azeotropic distillation tower, and the remaining liquid is transported to the heat exchanger.

8. The separation method of the ethylene glycol and 1,2-butanediol separation device according to claim 5, characterized in that: The mixed material of ethylene glycol and 1,2-butanediol containing 45-50% (wt%) of 1,2-butanediol is heated to 70-110° C. by a raw material heater and enters the extraction tower from the top of the extraction tower.

9. The separation method of the ethylene glycol and 1,2-butanediol separation device according to claim 5, characterized in that: The mass of the solvent is 3 to 4.5 times the mass of the mixture of ethylene glycol and 1,2-butanediol containing 45 to 50% (wt%) of 1,2-butanediol; the water consumption of the water washing tower is 0.3 to 0.5 times the mass of the mixture of ethylene glycol and 1,2-butanediol containing 45 to 50% (wt%) of 1,2-butanediol.

10. The separation method of the ethylene glycol and 1,2-butanediol separation device according to claim 5, characterized in that: The pressure at the top of the azeotropic distillation tower is -0.08~-0.095MPa.

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