Method for separating alcohol from water through ion liquid extraction and rectification

A technology of extractive distillation and ionic liquid, which is applied in the field of rectification and separation, and can solve the problems of non-compliance with energy saving and emission reduction, and high energy consumption of azeotropic distillation

Inactive Publication Date: 2013-05-01
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Patent CN1524006A uses ionic liquid as entrainer to separate near-boiling point or azeotropic mixture, but azeotropic rectification consumes a lot of energy and does not meet the requirem

Method used

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  • Method for separating alcohol from water through ion liquid extraction and rectification
  • Method for separating alcohol from water through ion liquid extraction and rectification
  • Method for separating alcohol from water through ion liquid extraction and rectification

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Such as figure 1 The extractive distillation process shown. The extractive distillation column has 25 theoretical trays (the number of trays is counted from top to bottom), and the ionic liquid [EMIM][Ac] is used as the extraction agent to add from the third plate, with a flow rate of 100kg / h, ethanol and water The mixture is added from the 20th theoretical plate, consisting of 50wt% ethanol and 50wt% water, with a flow rate of 100kg / h. The extractive distillation tower operates under normal pressure, the reflux ratio at the top of the tower is 1.8, and the output at the top of the tower is 50kg / h. As a result, an ethanol product with a mass fraction of 99.80% is obtained at the top of the tower, and the temperature at the top of the extractive distillation tower is 78.3 °C, the temperature of the tower kettle was 115.3 °C.

[0022] The tower stream of the extractive distillation tower enters the solvent recovery flash tank. The operating conditions of the solvent rec...

Embodiment 2

[0024] Such as figure 1 The extractive distillation process shown. The extractive distillation column has 25 theoretical trays (the number of trays is counted from top to bottom), and the ionic liquid [EMIM][Ac]+5wt%KAc is used as the extraction agent to add from the third plate, and the flow rate is 80kg / h. The mixture of ethanol and water is added from the 20th theoretical plate, consisting of 60wt% ethanol and 40wt% water, with a flow rate of 100kg / h. The extractive distillation tower operates under normal pressure, the reflux ratio at the top of the tower is 2.0, and the output at the top of the tower is 60kg / h. As a result, an ethanol product with a mass fraction of 99.70% is obtained at the top of the tower, and the temperature at the top of the extractive distillation tower is 78.3 °C, the temperature of the tower kettle was 115.3 °C.

[0025] The tower stream of the extractive distillation tower enters the solvent recovery flash tank. The operating conditions of the ...

Embodiment 3

[0027] Such as figure 1 The extractive distillation process shown. The extractive distillation column has 25 theoretical plates (the number of plates is counted from top to bottom), and the ionic liquid [EMIM][Ac]+5wt%NaAc is used as the extraction agent to add from the third plate, and the flow rate is 70kg / h. The mixture of ethanol and water is added from the 20th theoretical plate, consisting of 70wt% ethanol and 30wt% water, with a flow rate of 100kg / h. The extractive distillation tower operates under normal pressure, the top reflux ratio is 3.0, and the output at the top of the tower is 70kg / h. As a result, an ethanol product with a mass fraction of 99.20% is obtained at the top of the tower, and the temperature at the top of the extractive distillation tower is 78.3 °C, the temperature of the tower kettle was 118.0 °C.

[0028] The tower bottom stream of the extractive distillation tower enters the solvent recovery flash tank. The operating conditions of the solvent re...

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Abstract

The invention belongs to the technical field of rectification separation, and relates to a method for separating alcohol from water through ion liquid extraction and rectification, in particular to a method for separating alcohol from the water through extraction and rectification with an ion liquid and a compound solvent of the ion liquid. The method comprises the steps that an ion liquid [EMIM][Ac] and inorganic salt serve as extraction agents for separating alcohol from the water, wherein a mass fraction of inorganic salt is 0-20%; a high-purity alcohol product formed by crossing azeotrope can be obtained from the top of an extraction and rectification tower on the conditions that the extraction and rectification tower is at atmospheric pressure, a mass flow ratio of the extraction agents to a raw material is 0.5-6.0, and a reflux ratio is 1.0-5.0; a solvent recovery flash tank operates on the conditions that reduction pressure is 0.05-0.5atm and a temperature is 120-200 DEG C; and an extraction agent obtained from a tower kettle is recycled. With the method, the selectivity is improved significantly, and azeotropy of alcohol and the water is broken, so that a concentration of alcohol can be formed by the crossing azeotrope.

Description

technical field [0001] The invention relates to a method for separating ethanol and water, in particular using ionic liquid or a composite solvent of ionic liquid plus inorganic salt as an extractant to separate ethanol and water, and belongs to the technical field of rectification separation. Background technique [0002] Absolute ethanol is an important chemical reagent and an energy-saving and environment-friendly green fuel. Ethanol and water are widely used in industry, especially when the molar fraction of ethanol is 0.9, an azeotrope will be formed, and higher purity ethanol cannot be obtained by using traditional separation techniques and separating agents. In this case, ethanol and water are usually separated by special distillation (eg, azeotropic distillation, extractive distillation). Because azeotropic distillation consumes a lot of energy, extractive distillation is often used to separate ethanol and water in actual industrial production, and the choice of ext...

Claims

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Application Information

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IPC IPC(8): C07C31/08C07C29/84
Inventor 雷志刚席晓敏代成娜刘星陈标华
Owner BEIJING UNIV OF CHEM TECH
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