Method for separating low-concentration 1,2-butanediol from ethylene glycol by adopting azeotropic distillation

A technology of azeotropic distillation and azeotropic distillation column, which is applied in the field of refining high-purity ethylene glycol, can solve the problems of increasing the complexity of the process and operating energy consumption, so as to reduce equipment investment and energy consumption, and achieve important economic value , The effect of simplifying the separation process

Active Publication Date: 2018-05-11
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The above extractive distillation, azeotropic distillation and other methods all need to introduce a third component to realize the separation of ethylene glycol and 12BDO, and in order to recover the extractant or entrainer, it is necessary to design an additional recovery tower, which increases the complexity of the process. Complexity and operating energy consumption

Method used

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  • Method for separating low-concentration 1,2-butanediol from ethylene glycol by adopting azeotropic distillation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] The flow rate is 1000kmol / hr, the raw material containing 99.8% ethylene glycol (EG) and 0.2% (mol) 1,2-butanediol (12BDO) enters the EG-12BDO separation tower T101 together with dimethyl oxalate (DMO) , the operating pressure of the separation tower T101 is 10bar, the number of plates is 60, and the reflux ratio is 10; the bottom of the tower is the azeotropic mixture of EG and the entrainer DMO, and the mixture at the bottom of the tower then enters the EG refining tower T104; the top of the tower is the mixture of DMO and 12BDO , then enter the low-pressure azeotropic distillation column T102;

[0030] The operating pressure of EG refining tower is 10bar, plate number 72, reflux ratio 12; Obtain the EG product of 994.3kmol / h, 99.9% (mol) at the bottom of the tower of refining tower; Tower top is DMO, returns to as entrainer circulation Separation tower T101;

[0031] The operating pressure of the low-pressure azeotropic rectification tower T102 is 5 bar, the plate n...

Embodiment 2

[0034] The flow rate is 1000kmol / hr, the raw material containing EG99.8% and 12BDO0.2% (mol) enters the EG-12BDO separation tower T101 together with DMO, the operating pressure of the separation tower T101 is 10bar, the number of plates is 60, and the reflux ratio is 10 The tower bottom is the mixture of EG and entrainer DMO, and the mixture at the bottom of the tower enters the EG refining tower T104 subsequently; The tower top is the azeotropic mixture of DMO and 12BDO, enters the low-pressure azeotropic rectification tower T102 subsequently;

[0035] The operating pressure of the EG refining tower T104 is 10 bar, the number of plates is 72, and the reflux ratio is 12; the EG product of 995.6 kmol / h and 99.9% (mol) is obtained at the bottom of the tower, and the top of the tower is DMO, which is recycled back to the separation tower as an entrainer T101;

[0036] The operating pressure of the low-pressure azeotropic distillation column T102 is 5 bar, the number of plates is ...

Embodiment 3

[0039] Flow rate is 1000kmol / hr, contains EG 95%, and the raw material containing 12BDO 5% (mol) enters EG-12BDO separating tower T101 together with DMO, and the operating pressure of separating tower T101 is 9bar, plate number 70, flow ratio 8; The bottom is a mixture of EG and the entrainer DMO, and the bottom mixture then enters the EG refining tower T104; the top of the separation tower T101 is the azeotropic mixture of DMO and 12BDO, and the top mixture then enters the low-pressure azeotropic distillation tower T102;

[0040] The operating pressure of the EG refining tower T104 is 9 bar, the number of trays is 84, and the reflux ratio is 8; the EG product of 947.9 kmol / h and 99.9% (mol) is obtained at the bottom of the tower, and the top of the tower is DMO, which is recycled to the T101 tower as an entrainer;

[0041] The operating pressure of the low-pressure azeotropic distillation column T102 is 8 bar, the number of trays is 75, and the reflux ratio is 11; 49.635 kmol / ...

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Abstract

The invention discloses a method for separating low-concentration 1,2-butanediol (12BDO) from ethylene glycol (EG) by adopting an azeotropic distillation method. The method comprises the steps of feeding EG-12BDO and an azeotrope agent DMO into an ethylene glycol separating tower, wherein a mixture of the EG and the azeotropic agent DMO is formed at a tower bottom; further refining the tower bottom mixture to obtain the EG; for an azeotrope of the 12BDO and the DMO at a tower top of the separating tower, sequentially carrying out low-pressure azeotropy and high-pressure azeotropy, and respectively separating out the 12BDO and the DMO, wherein the azeotrope agent DMO can be recycled. The method provided by the invention solves the problem that in a process for preparing the ethylene glycolthrough coal-based synthesis gas, the ethylene glycol tower top product ethylene glycol and a mixture of another byproduct dihydric alcohol are difficult to separate. According to the process providedby the invention, the main product ethylene glycol is high in purity and high in yield, and the azeotrope agent DMO can be repeatably recovered and recycled; by adopting the hydrogenation reaction raw material DMO as the azeotrope agent, the introduction of a third component is also avoided, so that a separating flow of the EG is simplified, the equipment investment and the energy consumption ofthe whole process are reduced, and the method has an important economic value.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and specifically relates to a method for separating low-concentration 1,2-butanediol (12BDO) from ethylene glycol by azeotropic rectification, which is used in the process of preparing ethylene glycol from coal-based synthesis gas Refining of medium and high purity ethylene glycol. Background technique [0002] Ethylene glycol (EG) is an important chemical raw material, mainly used in the production of polyester fibers, polyester plastics, antifreeze, lubricants, plasticizers, explosives and chemical intermediates. The process routes for synthesizing EG mainly include petroleum route, coal-to-EG route and biomass-to-EG route. At present, the dominant route is still petroleum route—ethylene oxide hydration method. With the increasing shortage of petroleum resources, the development of C1 chemical industry based on natural gas and coal-based raw materials has important practical signific...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C29/82C07C31/20
CPCC07C29/82C07C31/207
Inventor 沈荣春李伟周静红郑赛男孙建磊
Owner EAST CHINA UNIV OF SCI & TECH
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