Method for recovering dilute acetic acid by virtue of extraction-azeotropic distillation of sec-butyl acetate

A technology of sec-butyl acetate and azeotropic distillation, applied in the field of chemical production, can solve problems such as low separation efficiency, and achieve the effects of simple replacement process, strong water-carrying ability, and small loss of entrainer

Inactive Publication Date: 2011-08-17
FUZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to solve the problem of low separation efficiency in the process of recovering acetic acid in dilute acetic acid in the prior art, the present inv...

Method used

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  • Method for recovering dilute acetic acid by virtue of extraction-azeotropic distillation of sec-butyl acetate
  • Method for recovering dilute acetic acid by virtue of extraction-azeotropic distillation of sec-butyl acetate
  • Method for recovering dilute acetic acid by virtue of extraction-azeotropic distillation of sec-butyl acetate

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Experimental program
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Embodiment 1

[0035] Such as figure 1 As shown, the flow rate sent to the top of the extraction tower through line 1 is 6m 3 / h, dilute acetic acid solution with acetic acid concentration of 26.54%, the flow rate sent from pipeline 2 to the bottom of the extraction tower is 17.5m 3 / h, the concentration is 97.87% sec-butyl acetate, after countercurrent extraction in the extraction tower T1, the flow rate of the extraction phase at the top of the tower is 1.851 m 3 / h, containing 9.077% acetic acid, the flow rate of the raffinate phase in the tower kettle is 4.008m 3 / h contains 0.7% acetic acid concentration. The extract phase (stream 3) from the top of the extraction tower is sent to the 25th theoretical plate of the azeotropic distillation column, and the raffinate phase (stream 5) from the bottom of the tower is sent to the solvent recovery tower T3 to recover the solvent therein. The flow rate of 69.0 m is added to the top of the azeotropic distillation column T2 through the pipeline...

Embodiment 2

[0037] Such as figure 1 As shown, the flow rate sent to the top of the extraction tower through line 1 is 6m 3 / h, the concentration of acetic acid is 10% dilute acetic acid solution, and the flow rate sent from pipeline 2 to the bottom of the extraction tower is 17.5m 3 / h, the concentration is 97.79% sec-butyl acetate, after countercurrent extraction in the extraction tower T1, the flow rate of the extraction phase at the top of the tower is 17.935 m 3 / h, containing 3.6% acetic acid, the flow rate of the raffinate phase in the tower kettle is 5.255m 3 / h contains 0.3% acetic acid concentration. The extract phase (stream 3) from the top of the extraction tower is sent to the 25th theoretical plate of the azeotropic distillation column, and the raffinate phase (stream 5) from the bottom of the tower is sent to the solvent recovery tower T3 to recover the solvent therein. Adding flow to the top of azeotropic distillation column T2 through line 6 is 31.5m 3 / h, the concentr...

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Abstract

The invention relates to a method for recovering dilute acetic acid by virtue of extraction-azeotropic distillation of sec-butyl acetate. In the method, the sec-butyl acetate is an extractant of an extraction tower and an entrainer of an azeotropic distillation tower. The method is characterized in that a part of dilute acetic acid is fed into the top of a filler extraction tower, a small portion of tower top reflux liquid of the azeotropic distillation tower is used as the extratant to be fed to the bottom of the extraction tower, and is subjected to room temperature counter current contact extraction together with the dilute acetic acid; an extraction phase containing the sec-butyl acetate, acetic acid and little water is obtained on the top of the extraction tower; raffinate water containing trace acetic acid is obtained at a tower kettle, and enters into a solvent recovering tower; and the extraction phase in the extraction tower is fed to the upper half part of the azeotropic distillation tower for further concentration, and the other part of sec-butyl acetate is fed to the tower top of the azeotropic distillation tower. The method has the characteristic of high separation efficiency; and the recovery of the acetic acid is more than 95%, and the content of the acetic acid in waste water is below 0.5%. By using the method, the defects of large reflux ratio, high energy consumption and the like which are caused by using a rectification method are directly overcome, and the production capability of dilute acetic acid recovery is enlarged.

Description

technical field [0001] The invention belongs to the technical field of chemical production, and more specifically relates to a method for recovering dilute acetic acid through sec-butyl acetate extraction-azeotropic rectification. Background technique [0002] Acetic acid is an important organic chemical raw material, widely used in basic organic synthesis, medicine, food, dyes, spices, pesticides and other industries, such as PX solvent in PTA production, raw material in PVA industry, pharmaceutical industry As a solvent, etc., a large amount of acetic acid wastewater will be discharged in these industrial production processes. "National Industrial Emission Standards" stipulates that the content of acetic acid in wastewater discharge should be less than 2% (mass percentage). Although the concentration of acetic acid in these acetic acid wastewater is very low, the total amount of acetic acid wastewater produced in industrial production is large. Therefore, the separation o...

Claims

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Application Information

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IPC IPC(8): C07C53/08C07C51/46
Inventor 邱挺吴燕翔黄智贤王莹淑郑辉东王碧玉李玲
Owner FUZHOU UNIV
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