Acetic acid and water separation method in aromatic carboxylic acid production

A separation method and technology of aromatic carboxylic acid, applied in the separation/purification of carboxylic acid compounds, organic chemistry, etc., to achieve the effect of reducing energy, saving energy and reducing energy consumption

Active Publication Date: 2016-01-27
SINOPEC YANGZI PETROCHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0017] In the above method, in order to reduce the separation energy, on the azeotropic rectification tower, adopt different entrainers or adopt two towers rectification containing extraction tower In the combined process, in the follow-up recovery of the entrainer, the separation method based on the extraction and the block copolymer composed of polyamide elastomer and polyether part is used as the separation membrane, which saves a certain amount of energy, but the extraction tower and the azeotrope essence Distillation column combination, due to the limitation of the reflux flow rate of the entrainer, can not use too much entrainer to enter the middle of the azeotrope column, which limits the flow rate of the feedstock with high water content entering the azeotrope rectification column, and at the same time, When using an extraction tower for feed concentration, the requirements for feed flow and components are high, and the content of acetic acid and entrainer in the extracted wastewater is high, which not only limits the effect of energy saving, but also leads to the loss of part of acetic acid and entrainer

Method used

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  • Acetic acid and water separation method in aromatic carboxylic acid production
  • Acetic acid and water separation method in aromatic carboxylic acid production
  • Acetic acid and water separation method in aromatic carboxylic acid production

Examples

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Effect test

Embodiment 1

[0045] use figure 1 The traditional azeotropic distillation process separates acetic acid and water, wherein the entrainer is sec-butyl acetate. The stream 1a that needs to be separated by acetic acid and water is composed of stream 1, stream 3 and stream 4, which come from different units of the terephthalic acid system respectively, wherein stream 1, stream 3 and stream 4 and Its process parameters are shown in Table 1 below. According to the different material states and water concentrations of each stream, the respective feeding positions in the traditional azeotropic distillation column are shown in Table 1. Wherein the dilute acetic acid stream 1 enters the azeotropic rectification column at the position of the tray 9 . At the top of the azeotropic rectification tower 2, the replenishment of the entrainer sec-butyl acetate is carried out by the stream 21, and the steam stream 6 flowing out from the top of the tower enters the condenser 5 to be condensed into a liquid ...

Embodiment 2

[0048] The entrainer that adopts is changed into isobutyl acetate, wherein stream 1, stream 3, stream 4 and process parameters thereof are as shown in Table 2 below, and other implementation processes are with embodiment 1. The stream 35 refluxed to the top of the azeotropic distillation column contains acetic acid with a concentration≦0.05wt%. The mass concentration of the acetic acid solvent 23 obtained at the bottom of the azeotropic distillation tower was 95%, and the relevant data of the whole system are shown in Table 3.

[0049]

Embodiment 3

[0051] use figure 2 Described azeotropic rectification process of the present invention separates acetic acid and water, and wherein entrainer is sec-butyl acetate, and the vaporization membrane in the pervaporation membrane separator uses commercially available polydimethylsiloxane / aromatic polyamide Composite film. The dilute acetic acid stream 1 in Example 1 (Table 1) first enters the pervaporation membrane separator for processing, using 240m 2 Polydimethylsiloxane / aromatic polyamide composite membrane, keep the vaporized membrane side temperature at 267K through a jet mixer, and get 4.98kg / m 2 The water permeation flux of h, the material that does not pass through the vaporization membrane is the acetic acid enrichment stream 1b of acetic acid content close to 50wt%, then the acetic acid enrichment stream 1b enters the azeotropic rectification tower through the position of tray 18, other Implementation process is the same as embodiment 1. The stream 35 refluxed to the...

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Abstract

The present invention relates to an acetic acid and water separation method in aromatic carboxylic acid production. According to the method, during an aromatic carboxylic acid production process, a material containing acetic acid and water is introduced into a pervaporation membrane separator, the high water content material is concentrated by using a membrane separation method to form an high acetic acid concentration material, the high acetic acid concentration material enters an azeotropic rectification tower, and separation is performed, such that the amount of the water entering the azeotropic rectification tower is reduced, and the energy for the azeotropic rectification is reduced. According to the present invention, the acetic acid accepted by the system and the water can be obtained; and compared with the original azeotropic rectification method, the method of the present invention has the following characteristics that the energy required by the reboiler and the condenser achieving the separation target is reduced, and the energy is further saved by 15-30% on the basis of the azeotropic rectification.

Description

field of invention [0001] The invention relates to a method for separating acetic acid and water in the production of aromatic carboxylic acids, especially in the production process of aromatic dibasic acids, the energy saving of azeotropic distillation and separation of acetic acid and water is realized by adopting the method of enriching feed acetic acid. Background of the invention [0002] The traditional production process of aromatic carboxylic acids is usually obtained by liquid-phase air oxidation of alkylaromatics under high pressure. Liquid-phase oxidation of alkylaromatics is the gradual oxidation of alkyl groups on aromatics to aldehydes and carboxylic acids in the presence of an aqueous medium containing acetic acid and a metal catalyst system, and finally aromatic carboxylic acids are obtained. [0003] The oxidation process of alkylaromatics will generate a lot of heat. In order to keep the temperature of the reaction process stable, the heat is usually remov...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C53/08C07C51/42C07C51/46
Inventor 刘建新肖翔孟海钱学勤邢跃军朱伟周永兵
Owner SINOPEC YANGZI PETROCHEM
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