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A method for separating m-xylene from xylene

A technology for m-xylene and xylene, which is applied in the field of separation of m-xylene, can solve the problems of environmental pollution, adsorption process and complicated control, and achieves the effects of simple process and convenient operation.

Active Publication Date: 2017-06-16
SINOPEC YANGZI PETROCHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, the sulfonation method, complexation method, reactive distillation method, etc. produce waste acid in the process, which is easy to cause environmental pollution; while the process flow and control of the adsorption method are more complicated.

Method used

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  • A method for separating m-xylene from xylene

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Such as figure 1 As shown, xylene is rectified to remove o-xylene to obtain a mixture of 10% ethylbenzene, 40% p-xylene, and 50% m-xylene, and then add the resulting mixture to the azeotropic distillation column, and simultaneously press normal Butanol: (p-xylene + ethylbenzene) = 3: 1 (mass percentage) ratio Add entrainer n-butanol to the azeotropic rectification tower; control the azeotropic rectification tower top temperature to 117 ° C, the tower The number of plates is N=50, the reflux ratio R=4, and the material composition of the tower tank obtained after azeotropic distillation is: 99.62% m-xylene, 0.28% p-xylene, and 0.1% ethylbenzene. The top product is post-treated to obtain a mixture of p-xylene and ethylbenzene and an entrainer, and the entrainer is recycled.

Embodiment 2

[0023] Xylene is rectified to remove o-xylene to obtain a mixture of 10% ethylbenzene, 40% p-xylene and 50% m-xylene, and then put the resulting mixture into the azeotropic distillation column, and press n-butanol at the same time: (p-xylene + ethylbenzene) = 3:1 (mass percentage) ratio to add entrainer n-butanol to the azeotropic distillation column; control the top temperature of the azeotropic distillation column to be 117°C, and the number of plates to be N=70, reflux ratio R=5, the material composition of the tower tank obtained after azeotropic distillation is: m-xylene 99.76%, p-xylene 0.17%, ethylbenzene 0.07%. The top product is post-treated to obtain a mixture of p-xylene and ethylbenzene and an entrainer, and the entrainer is recycled.

Embodiment 3

[0025] Rectify xylene to remove o-xylene to obtain a mixture of 33.3% ethylbenzene, 33.3% p-xylene, and 33.4% m-xylene, and then add the resulting mixture to the azeotropic distillation column, and press n-butanol at the same time: (p-xylene + ethylbenzene) = 3:1 (mass percentage) ratio to add entrainer n-butanol to the azeotropic distillation column; control the top temperature of the azeotropic distillation column to be 117°C, and the number of plates to be N=50, reflux ratio R=4, the material composition of the tower tank obtained after azeotropic distillation is: m-xylene 99.62%, p-xylene 0.24%, ethylbenzene 0.14%. The top product is post-treated to obtain a mixture of p-xylene and ethylbenzene and an entrainer, and the entrainer is recycled.

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Abstract

The invention discloses a method for separating m-xylene from xylene, which comprises the following steps connected in sequence: A. rectifying xylene containing p-xylene, m-xylene, o-xylene and ethylbenzene to remove o-xylene Xylene, obtain the mixture that contains p-xylene, m-xylene and ethylbenzene; B, the mixture that step A gained is sent in the azeotropic rectification tower, and add entrainer, by azeotropic rectification m-xylene Separate from ethylbenzene and p-xylene to obtain m-xylene; the entrainer is a substance that can form an azeotrope with p-xylene and ethylbenzene respectively, and the difference between the azeotropic point and the boiling point of m-xylene is more than 8°C. The method for separating meta-xylene from xylene in the present invention can separate more than 99.5% of meta-xylene from mixed xylene by means of rectification, the process is simple, easy to operate, and easy to operate. Environmentally harmful substances; the mixture of p-xylene and ethylbenzene obtained at the top of the tower can be used as a raw material for p-xylene adsorption.

Description

technical field [0001] The invention relates to a method for separating m-xylene from xylene. Background technique [0002] Meta-xylene is one of the isomers of xylene. The appearance is a colorless transparent liquid with a boiling point of 139°C. It has a smaller boiling point difference with other isomers of xylene, such as p-xylene and ethylbenzene. The method is difficult to separate m-xylene. The commonly used m-xylene production methods in industry include sulfonation separation method, complexation separation method, adsorption separation method, reactive distillation method and so on. The sulfonation separation method is an earlier m-xylene separation method. It uses the principle that m-xylene is easy to be sulfonated and hydrolyzed to achieve the purpose of separation. The mixed xylene is sulfonated with concentrated sulfuric acid, rehydrolyzed, and distilled to obtain m-xylene. xylene. The complex separation method uses the characteristics of some compounds an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C15/08C07C7/04C07C7/06
Inventor 汪洋王亚明任珉刘宗健胡维强袁浩
Owner SINOPEC YANGZI PETROCHEM