阅读说明：本技术 一种煤制乙二醇产品及副产品分离提纯工艺 (Coal-to-ethylene glycol product and byproduct separation and purification process ) 是由 段志广 郭全伟 沈琦 王书涛 郑善龙 于 2019-09-20 设计创作，主要内容包括：本发明提供了一种煤制乙二醇产品及副产品分离提纯工艺,涉及草酸二甲酯分离技术领域,该工艺通过预分离、脱醇、脱水、脱醇、乙醇回收、乙二醇回收、加氢、乙二醇精制的工艺,将煤制粗乙二醇精制得到乙二醇产品。产品各项指标达到或超过GB/T 4649-2018中规定的各项指标,是一种乙二醇装置工业化后实现达标达产、高收率、高聚酯品率先进工艺。(The invention provides a separation and purification process of coal-made ethylene glycol products and byproducts, which relates to the technical field of dimethyl oxalate separation. The indexes of the product reach or exceed the indexes specified in GB/T4649-2018, and the process is an advanced process for achieving the yield reaching the standard, high yield and high polyester yield after the ethylene glycol device is industrialized.)

1. A separation and purification process for coal-to-ethylene glycol products and byproducts is characterized by comprising the following steps:

(1) according to different temperature control of a hydrogenation synthesis system, the crude ethylene glycol and the crude methanol are subjected to fractional condensation;

(2) crude methanol enters from the middle part of a methanol product tower, light components such as methyl formate, dimethyl ether and the like are removed from the top of a methanol recovery tower and taken as light components to be extracted, a methanol product extracted from the side line returns to a system for reuse, and crude glycol with most of methanol removed from the tower kettle is discharged from the tower kettle;

(3) the crude glycol and the material discharged from the tower kettle of the methanol recovery tower enter from the middle part of the methanol removing tower, the methanol in the raw material liquid removed from the tower top of the methanol removing tower returns to the methanol product tower, and the crude glycol removed from the methanol in the tower kettle of the methanol removing tower is discharged from the tower kettle;

(4) the bottom liquid of the methanol removing tower enters from the middle part of the dehydrating tower, the components with the boiling point lower than that of water are separated from the top of the dehydrating tower, and the crude glycol with light components removed from the tower kettle is discharged from the tower kettle;

(5) extracting the methanol from the top of the dehydration tower, returning the methanol to a methanol recovery tower for recovering the methanol, sending the ethanol solution in the tower bottom to an ethanol product tower, feeding the tower bottom liquid of the ethanol removal tower from the middle part of the ethanol product tower, extracting an ethanol product from the tower top, and sending the wastewater in the tower bottom to sewage treatment;

(6) crude glycol at the bottom of the dehydration tower enters a dealcoholization tower, light components with the boiling point lower than that of 1, 2-butanediol and the like are removed at the top of the dealcoholization tower, and materials with the boiling point lower than that of the glycol are further removed and discharged from a tower kettle;

(7) sending light components extracted from the top of the dealcoholization tower into an ethylene glycol concentration tower, extracting mixed alcohol esters such as 1,2 butanediol, ethylene glycol and the like from the top of the ethylene glycol concentration tower, and returning the ethylene glycol recovered from the tower bottom into the dealcoholization tower;

(8) glycol at the bottom of the dealcoholization tower enters an ethylene glycol product tower from the middle part, part of the glycol collected at the top of the dealcoholization tower is sent to liquid phase hydrogenation, polyester grade glycol is collected at the side line, and the glycol at the bottom of the dealcoholization tower is sent to an ethylene glycol recovery tower;

(9) feeding the tower bottom liquid of the ethylene glycol product into an ethylene glycol recovery tower from the middle part, feeding the top produced liquid into a liquid phase for hydrogenation, and feeding the ethylene glycol containing heavy components such as diethylene glycol, triethylene glycol and the like in the tower bottom into a tank area for export;

(10) mixing ethylene glycol and hydrogen extracted from the tops of the ethylene glycol product tower and the ethylene glycol recovery tower, feeding the mixture into a liquid phase hydrogenation optimization circulation component, returning the optimized component to the dealcoholization tower, wherein the liquid phase hydrogenation operation pressure is 0.2-0.6MPa, and the temperature is 110-.

2. The process for separating and purifying coal glycol products and byproducts as claimed in claim 1, wherein the operating pressure of the methanol product tower is 90-100KPa.A, the temperature at the top of the tower is 60-65 ℃, the temperature at the bottom of the tower is 64-66 ℃, and the reflux ratio is 2-3.

3. The process for separating and purifying coal glycol product and byproduct as claimed in claim 1, wherein the operating pressure of the methanol removing tower is 70-80KPa.A, the temperature at the top of the tower is 56-58 ℃, the temperature at the bottom of the tower is 145-155 ℃, and the reflux ratio is 1: 1.

4. the process for separating and purifying coal glycol product and byproduct as claimed in claim 1, wherein the operating pressure of the dehydration tower is 20-30KPa.A, the temperature at the top of the tower is 53-65 ℃, the temperature at the bottom of the tower is 142-160 ℃, and the reflux ratio is 2-3.

5. The process for separating and purifying coal glycol products and byproducts as claimed in claim 1, wherein the operating pressure of the de-ethanol tower is 90-100KPa.A, the temperature at the top of the tower is 58-62 ℃, the temperature at the bottom of the tower is 64-70 ℃, and the reflux ratio is controlled to be 9: 1.

6. the process for separating and purifying coal glycol product and byproducts as claimed in claim 1, wherein the operating pressure of the ethanol product tower is 230-250KPa.A, the tower top temperature is 98-104 ℃, the tower bottom temperature is 116-124 ℃, and the reflux ratio is controlled to be 8: 1.

7. the process for separating and purifying coal glycol products and byproducts as claimed in claim 1, wherein the operating pressure of the dealcoholization tower is 10-15KPa.A, the temperature at the top of the tower is 133-140 ℃, the temperature at the bottom of the tower is 150-158 ℃, the content of 1-2 butanediol in the bottom of the tower is less than 0.01%, and the reflux ratio is 30-40.

8. The process for separating and purifying coal glycol product and byproducts as claimed in claim 1, wherein the operating pressure of the glycol concentration tower is 10-14KPa, the tower top temperature is 110-.

9. The process for separating and purifying coal glycol product and byproducts as claimed in claim 1, wherein the operating pressure of the glycol recovery tower is 12-15KPa, the temperature at the top of the tower is 138-.

10. The process for separating and purifying coal glycol product and byproducts as claimed in claim 1, wherein the operating pressure of the glycol recovery tower is 5-10KPa, the temperature at the top of the tower is 116-120 ℃, the temperature at the bottom of the tower is 126-130 ℃, and the reflux ratio is 1.0-1.5.

Technical Field

The invention relates to the technical field of dimethyl oxalate separation, in particular to a separation and purification process for a coal-to-ethylene glycol product and a byproduct.

Background

Ethylene glycol is an important chemical raw material, and is mainly used for preparing polyester terylene, polyester resin, moisture absorbent, plasticizer, surfactant, synthetic fiber, cosmetics and explosive, and also used as solvent for dye, ink and the like, antifreeze agent for preparing engine, gas dehydrating agent, and wetting agent for preparing resin, glass paper, fiber, leather and adhesive. Can produce synthetic resin PET, fiber grade PET is polyester fiber, and bottle grade PET is used for manufacturing mineral water bottles and the like. Alkyd resins, glyoxal and the like can also be produced and are also used as antifreeze agents. In addition to being used as antifreeze for automobiles, it is also used for the transport of industrial refrigeration, commonly referred to as coolant, and can also be used as a condensing agent as well as water. Therefore, the coal is efficiently converted into chemical raw materials such as ethylene glycol and the like, the dependence of the chemical raw materials on petroleum resources is reduced, the optimization of energy and resource structures is facilitated, and the method has important significance.

The current technical routes for preparing ethylene glycol mainly comprise two types: the first is petroleum route, which is mainly to produce ethylene oxide by gas phase oxidation of ethylene on a silver catalyst, and then to prepare ethylene glycol product by liquid phase non-catalytic hydration, and has the advantages of mature technology and application range; the other method is a technical route for preparing the ethylene glycol from coal, wherein synthetic gas prepared from coal is used for preparing dimethyl oxalate, and then the dimethyl oxalate is hydrogenated to prepare the ethylene glycol. With the increasing shortage of petroleum resources in the world and the shortage of petroleum resource supply, the route for synthesizing ethylene glycol by using coal as a raw material is widely concerned by people, and the method for preparing ethylene glycol by using coal is most suitable for the current situation of China from the economic rationality of raw material selection and the energy structure composition of China.

The crude glycol produced by the coal-based glycol contains dozens of components such as glycol, methanol, trace 1, 2-butanediol, ethanol, water, diethylene glycol, triethylene glycol and the like, and the removal of impurities in the crude glycol to produce a high-quality glycol product is the focus of research at present.

Disclosure of Invention

The invention aims to provide a device for primarily separating dimethyl oxalate from coal-based ethylene glycol.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a process for separating and purifying coal-made ethylene glycol products and byproducts comprises the following steps:

(1) according to different temperature control of a hydrogenation synthesis system, the crude ethylene glycol and the crude methanol are subjected to fractional condensation;

(2) crude methanol enters from the middle part of a methanol product tower, light components such as methyl formate, dimethyl ether and the like are removed from the top of a methanol recovery tower and taken as light components to be extracted, a methanol product extracted from the side line returns to a system for reuse, and crude glycol with most of methanol removed from the tower kettle is discharged from the tower kettle;

(3) the crude glycol and the material discharged from the tower kettle of the methanol recovery tower enter from the middle part of the methanol removing tower, the methanol in the raw material liquid removed from the tower top of the methanol removing tower returns to the methanol product tower, and the crude glycol removed from the methanol in the tower kettle of the methanol removing tower is discharged from the tower kettle;

(4) the bottom liquid of the methanol removing tower enters from the middle part of the dehydrating tower, the components with the boiling point lower than that of water are separated from the top of the dehydrating tower, and the crude glycol with light components removed from the tower kettle is discharged from the tower kettle;

(5) extracting the methanol from the top of the dehydration tower, returning the methanol to a methanol recovery tower for recovering the methanol, sending the ethanol solution in the tower bottom to an ethanol product tower, feeding the tower bottom liquid of the ethanol removal tower from the middle part of the ethanol product tower, extracting an ethanol product from the tower top, and sending the wastewater in the tower bottom to sewage treatment;

(6) crude glycol at the bottom of the dehydration tower enters a dealcoholization tower, light components with the boiling point lower than that of 1, 2-butanediol and the like are removed at the top of the dealcoholization tower, and materials with the boiling point lower than that of the glycol are further removed and discharged from a tower kettle;

(7) sending light components extracted from the top of the dealcoholization tower into an ethylene glycol concentration tower, extracting mixed alcohol esters such as 1,2 butanediol, ethylene glycol and the like from the top of the ethylene glycol concentration tower, and returning the ethylene glycol recovered from the tower bottom into the dealcoholization tower;

(8) glycol at the bottom of the dealcoholization tower enters an ethylene glycol product tower from the middle part, part of the glycol collected at the top of the dealcoholization tower is sent to liquid phase hydrogenation, polyester grade glycol is collected at the side line, and the glycol at the bottom of the dealcoholization tower is sent to an ethylene glycol recovery tower;

(9) feeding the tower bottom liquid of the ethylene glycol product into an ethylene glycol recovery tower from the middle part, feeding the top produced liquid into a liquid phase for hydrogenation, and feeding the ethylene glycol containing heavy components such as diethylene glycol, triethylene glycol and the like in the tower bottom into a tank area for export;

(10) mixing ethylene glycol and hydrogen extracted from the tops of the ethylene glycol product tower and the ethylene glycol recovery tower, feeding the mixture into a liquid phase hydrogenation optimization circulation component, returning the optimized component to the dealcoholization tower, wherein the liquid phase hydrogenation operation pressure is 0.2-0.6MPa, and the temperature is 110-.

Furthermore, the operating pressure of the methanol product tower is 90-100KPa.A, the temperature at the top of the tower is 60-65 ℃, the temperature at the bottom of the tower is 64-66 ℃, and the reflux ratio is 2-3.

Further, the operating pressure of the methanol removing tower is 70-80KPa.A, the temperature of the tower top is 56-58 ℃, the temperature of the tower kettle is 145-155 ℃, and the reflux ratio is 1: 1.

furthermore, the operation pressure of the dehydration tower is 20-30KPa.A, the temperature at the top of the tower is 53-65 ℃, the temperature at the bottom of the tower is 142-160 ℃, and the reflux ratio is 2-3.

Further, the operating pressure of the de-ethanol tower is 90-100KPa.A, the tower top temperature is 58-62 ℃, the tower kettle temperature is 64-70 ℃, and the reflux ratio is controlled to be 9: 1.

further, the operation pressure of the ethanol product tower is 230-250KPa.A, the tower top temperature is 98-104 ℃, the tower bottom temperature is 116-124 ℃, and the reflux ratio is controlled to be 8: 1.

further, the operating pressure of the dealcoholization tower is 10-15KPa.A, the tower top temperature is 133-140 ℃, the tower bottom temperature is 150-158 ℃, the 1, 2-butanediol content in the tower bottom is less than 0.01 percent, and the reflux ratio is 30-40.

Further, the operation pressure of the ethylene glycol concentration tower is 10-14KPa, the tower top temperature is 110-.

Further, the operation pressure of the ethylene glycol recovery tower is 12-15KPa, the tower top temperature is 138-145 ℃, the tower bottom temperature is 148-154 ℃ and the reflux ratio is 1.0-2.0.

Further, the operation pressure of the ethylene glycol recovery tower is 5-10KPa, the tower top temperature is 116-120 ℃, the tower bottom temperature is 126-130 ℃, and the reflux ratio is 1.0-1.5.

The working principle and the advantages of the invention are as follows:

the invention has the advantages of reasonable process and high product quality. The purity of the obtained product is more than or equal to 99.9 percent, the side-stream glycol product meets the requirements of various indexes of GB/T4649-. The vacuum rectification and the heat coupling are fully utilized to reduce the energy consumption of the system and the cost.

Drawings

FIG. 1 is a flow chart of the process for separating and purifying coal-to-ethylene glycol products and byproducts.

Detailed Description

The invention provides a separation and purification process of a coal-to-ethylene glycol product and byproducts, which comprises the following steps:

(1) according to different temperature control of a hydrogenation synthesis system, the crude ethylene glycol and the crude methanol are subjected to fractional condensation;

(2) crude methanol enters from the middle part of a methanol product tower, light components such as methyl formate, dimethyl ether and the like are removed from the top of a methanol recovery tower and taken as light components to be extracted, a methanol product extracted from the side line returns to a system for reuse, and crude glycol with most of methanol removed from the tower kettle is discharged from the tower kettle;

(3) the crude glycol and the material discharged from the tower kettle of the methanol recovery tower enter from the middle part of the methanol removing tower, the methanol in the raw material liquid removed from the tower top of the methanol removing tower returns to the methanol product tower, and the crude glycol removed from the methanol in the tower kettle of the methanol removing tower is discharged from the tower kettle;

(4) the bottom liquid of the methanol removing tower enters from the middle part of the dehydrating tower, the components with the boiling point lower than that of water are separated from the top of the dehydrating tower, and the crude glycol with light components removed from the tower kettle is discharged from the tower kettle;

(5) extracting the methanol from the top of the dehydration tower, returning the methanol to a methanol recovery tower for recovering the methanol, sending the ethanol solution in the tower bottom to an ethanol product tower, feeding the tower bottom liquid of the ethanol removal tower from the middle part of the ethanol product tower, extracting an ethanol product from the tower top, and sending the wastewater in the tower bottom to sewage treatment;

(6) crude glycol at the bottom of the dehydration tower enters a dealcoholization tower, light components with the boiling point lower than that of 1, 2-butanediol and the like are removed at the top of the dealcoholization tower, and materials with the boiling point lower than that of the glycol are further removed and discharged from a tower kettle;

(7) sending light components extracted from the top of the dealcoholization tower into an ethylene glycol concentration tower, extracting mixed alcohol esters such as 1,2 butanediol, ethylene glycol and the like from the top of the ethylene glycol concentration tower, and returning the ethylene glycol recovered from the tower bottom into the dealcoholization tower;

(8) glycol at the bottom of the dealcoholization tower enters an ethylene glycol product tower from the middle part, part of the glycol collected at the top of the dealcoholization tower is sent to liquid phase hydrogenation, polyester grade glycol is collected at the side line, and the glycol at the bottom of the dealcoholization tower is sent to an ethylene glycol recovery tower;

(9) feeding the tower bottom liquid of the ethylene glycol product into an ethylene glycol recovery tower from the middle part, feeding the top produced liquid into a liquid phase for hydrogenation, and feeding the ethylene glycol containing heavy components such as diethylene glycol, triethylene glycol and the like in the tower bottom into a tank area for export;

(10) mixing ethylene glycol and hydrogen extracted from the tops of the ethylene glycol product tower and the ethylene glycol recovery tower, feeding the mixture into a liquid phase hydrogenation optimization circulation component, returning the optimized component to the dealcoholization tower, wherein the liquid phase hydrogenation operation pressure is 0.2-0.6MPa, and the temperature is 110-.

Wherein the operation pressure of the methanol product tower is 90-100KPa.A, the temperature at the top of the tower is 60-65 ℃, the temperature at the bottom of the tower is 64-66 ℃, and the reflux ratio is 2-3.

Wherein the operating pressure of the methanol removing tower is 70-80KPa.A, the temperature at the top of the tower is 56-58 ℃, the temperature at the bottom of the tower is 145-155 ℃, and the reflux ratio is 1: 1.

wherein the operation pressure of the dehydration tower is 20-30KPa.A, the temperature at the top of the tower is 53-65 ℃, the temperature at the bottom of the tower is 142-160 ℃, and the reflux ratio is 2-3.

Wherein, the operating pressure of the de-ethanol tower is 90-100KPa.A, the tower top temperature is 58-62 ℃, the tower kettle temperature is 64-70 ℃, and the reflux ratio is controlled to be 9: 1.

wherein, the operation pressure of the ethanol product tower is 230-250KPa.A, the tower top temperature is 98-104 ℃, the tower bottom temperature is 116-124 ℃, and the reflux ratio is controlled to be 8: 1.

wherein the operating pressure of the dealcoholization tower is 10-15KPa.A, the tower top temperature is 133-140 ℃, the tower bottom temperature is 150-158 ℃, the 1, 2-butanediol content in the tower bottom is less than 0.01 percent, and the reflux ratio is 30-40.

Wherein the operation pressure of the ethylene glycol concentration tower is 10-14KPa, the tower top temperature is 110-114 ℃, the tower bottom temperature is 122-128 ℃, and the reflux ratio is 3.0-4.0.

Wherein the operation pressure of the ethylene glycol recovery tower is 12-15KPa, the tower top temperature is 138-145 ℃, the tower bottom temperature is 148-154 ℃, and the reflux ratio is 1.0-2.0.

Wherein the operation pressure of the ethylene glycol recovery tower is 5-10KPa, the tower top temperature is 116-120 ℃, the tower bottom temperature is 126-130 ℃, and the reflux ratio is 1.0-1.5.

One of the specific embodiments of the invention is as follows:

referring to fig. 1, the process for separating and purifying the coal-derived ethylene glycol product and the byproducts comprises the following steps:

the crude methanol component after hydrogenation synthesis separation is methanol 96%, glycol: 2% and ethanol: 0.3%, water: 0.2%, 1.2 butanediol: 0.01%, ethylene carbonate: 0.02%, methyl formate: 0.001% and other trace components enter a methanol recovery tower.

The methanol recovery tower adopts steam heating to control the temperature of a tower kettle to be 64-66 ℃, after the vapor phase at the top of the tower is condensed, part of the vapor phase returns to the top of the tower to control the temperature at the top of the tower to be 60-61 ℃, part of the vapor phase is taken as fusel oil to extract and remove light components such as methyl formate, dimethyl ether and the like, and a superior grade methanol is taken out from a lateral line.

Controlling the reflux ratio of the methanol recovery tower between 2 and 3.0.

The crude glycol component after hydrogenation synthesis separation is glycol: 77%, methanol 22%, ethanol: 0.06%, 1.2 butanediol: 0.4%, water: 0.3%, ethylene carbonate: 0.03% of trace components enter a methanol removing tower.

The temperature of the bottom of the methanol recovery tower is controlled by adopting 1.7MPa steam to heat and control the temperature of the tower kettle to be 145-155 ℃, after the vapor phase at the top of the tower is condensed, a part of the vapor phase flows back to the top of the tower to control the temperature of the top of the tower to be 56-58 ℃, and a part of the methanol is extracted and returned to the methanol recovery tower.

Controlling the reflux ratio of the methanol removing tower in a range of 1: 1.

the demethanizer pressure is controlled by a vacuum pump at 70-72 KPa.A.

The methanol removing tower bottom liquid is sent to a dehydrating tower and heated to 142-160 ℃ by steam, and after the gas phase at the top of the tower is condensed, part of the gas phase flows back to the top of the tower to control the temperature at the top of the tower to be 53-65 ℃.

Controlling the reflux ratio of the dehydration tower between 2 and 3.

The pressure of the dehydration tower is controlled to be 20-30KPa.A by a vacuum pump.

The ethanol (30 percent of ethanol, 25 percent of methanol, 40 percent of water and 5 percent of methyl glycolate) extracted from the top of the dehydration tower is sent into a de-ethanol tower.

The pressure of the de-ethanol tower is controlled to be 90 KPa.

Heating the vapor phase at the top of the ethanol product to 64-70 deg.C in the ethanol removal tower

Condensing the vapor phase at the top of the ethanol removal tower to 50 ℃ by a condenser, recycling one part of the vapor phase to the ethanol removal tower, controlling the temperature at the top of the tower to be 58-62 ℃, and extracting the other part of the vapor phase as a methanol product with the purity of 99.9%.

Controlling the reflux ratio of the de-ethanol tower to be 9: 1

The tower bottom liquid of the de-ethanol tower enters an ethanol product tower from the middle part, and the tower bottom is heated to 116-124 ℃ by adopting steam.

Condensing the tower top steam of the ethanol product to 80 ℃. One part of the ethanol is refluxed to the top of the tower, the temperature of the top of the tower is controlled to be 98-104 ℃, the other part of the ethanol is extracted as an ethanol product, and the purity is more than or equal to 90 percent. And cooling the tower kettle wastewater to 40 ℃, and then delivering the wastewater to sewage treatment.

The tower pressure of the ethanol product is controlled to be 230KPa.A by a reflux tank pressure regulating valve.

Controlling the reflux ratio of the ethanol product tower to be 8: 1.

and (3) conveying the bottom liquid of the dehydration tower into a dealcoholization tower to separate and remove light components such as 1,2 butanediol, methyl glycolate and the like, wherein the tower is fed with a raw material containing ethylene glycol: 98.5%, 1,2 butanediol: 0.6%, methyl glycolate: 0.2 percent and the like.

Heating the tower kettle of the dealcoholization tower by adopting steam, controlling the temperature of the tower kettle to be 150-158 ℃, and feeding ethylene glycol (the content of 1, 2-butanediol is less than or equal to 100ppm) in the tower kettle into an ethylene glycol product tower.

After the vapor phase at the top of the dealcoholization tower is condensed, part of the reflux is carried out to control the temperature at the top of the dealcoholization tower to be 133-140 ℃, and the other part of the reflux is taken as a light component and is extracted to the ethylene glycol concentration tower.

Controlling the reflux ratio of the dealcoholization tower between 30 and 40.

The pressure of the dealcoholization tower is controlled at 10-15KPa.A by a vacuum pump.

The light components extracted from the top of the dealcoholization tower are sent into an ethylene glycol concentration tower from the middle part, and the tower kettle is heated to 122-128 ℃ by using steam. The 1, 2-butanediol and the ethylene glycol are separated again in the tower, and the ethylene glycol in the light component is recovered.

After the vapor phase at the top of the ethylene glycol concentration tower is condensed, part of the reflux is carried out to control the temperature at the top of the tower to be 110-114 ℃, part of the reflux is taken as mixed alcohol ester to be extracted to the outside of the tank area, and the ethylene glycol at the bottom of the tower returns to the dealcoholization tower.

The reflux ratio of the dealcoholization tower is controlled to be between 3.0 and 4.0.

The pressure of the dealcoholization tower is controlled to be 10-14KPa.A by a vacuum pump.

The bottom liquid of the dealcoholization tower enters an ethylene glycol product tower from the middle part, and the tower bottom is heated to 148-154 ℃.

After the vapor phase at the top of the ethylene glycol product is condensed, part of the vapor phase is refluxed to control the temperature at the top of the tower to be 138-145 ℃, and the other part of the vapor phase is taken as the liquid phase for hydrogenation, and polyester-grade ethylene glycol is extracted at the side line.

Controlling the reflux ratio of the ethylene glycol product tower to be 1.0-2.0.

The pressure of the ethylene glycol product is controlled to be 12-15KPa.A by a vacuum pump.

The bottom liquid of the ethylene glycol product tower enters an ethylene glycol recovery tower from the middle part, and the tower bottom is heated to 154 ℃.

After the vapor phase at the top of the ethylene glycol recovery tower is condensed, part of the reflux is carried out to control the temperature at the top of the tower to be 126 ℃ and 130 ℃, and the other part of the reflux is taken as produced liquid to be hydrogenated.

Controlling the reflux ratio of the ethylene glycol recovery tower to be between 1.0 and 1.5.

The pressure of the ethylene glycol recovery tower is controlled to be 5-10KPa.A by a vacuum pump.

Mixing ethylene glycol and hydrogen extracted from the tops of the ethylene glycol product tower and the ethylene glycol recovery tower, feeding the mixture into a liquid-phase hydrogenation optimization circulation component, and returning the optimized component to the dealcoholization tower.

The liquid phase hydrogenation operation pressure is 0.6MPa, and the temperature is 110-140 ℃.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.