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Method of preparing high-purity terephthalic acid

A technology for terephthalic acid and crude terephthalic acid, applied in sustainable manufacturing/processing, separation/purification of carboxylic acid compounds, chemical industry, etc., can solve problems such as insufficient energy recovery efficiency, and achieve energy saving volume effect

Active Publication Date: 2010-05-26
MITSUI CHEM INC
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In summary, although various methods have been proposed to use the steam generated by decompression cooling in the crystallization process as a heating source for CTA slurry, the energy recovery efficiency is not sufficient, and it is desired to develop a method that can be used more effectively. Method for producing steam generated by depressurization cooling

Method used

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  • Method of preparing high-purity terephthalic acid
  • Method of preparing high-purity terephthalic acid
  • Method of preparing high-purity terephthalic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0090] Such as figure 1 As shown, a manufacturing apparatus (n=4) with 4 heat exchangers and 4 crystallization tanks was used. Under the conditions shown in Table 2, the CTA slurry was heated, the obtained CTA aqueous solution was hydrogenated, and the energy efficiency when the obtained CTA treatment liquid was depressurized and cooled was evaluated. The energy efficiency was evaluated using the same exergy loss as in Comparative Example 1.

[0091] The temperature and pressure of the steam generated in each crystallization tank were set to be the same as in Comparative Example 1. The steam generated in the first crystallization tank (i=1) is introduced into the fourth heat exchanger (i=4). After depressurizing the condensate after the heat exchange to the same temperature and pressure as the steam generated in the second crystallization tank (i=2), the steam is introduced to form a high-temperature fluid, and the high-temperature fluid is introduced into the third heat exc...

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Abstract

The invention provides a method of preparing high-purity terephthalic acid, comprising: (I)the process of mixing raw terephthalic acid getting by liquid-phase oxidating paraxylene with water, formingraw terephthalic acid slurry; (II)the process of progressively heating the raw terephthalic acid slurry by many heat exchangers so as to dissolve it and form raw terephthalic acid solution; (III)the process of hydrotreating the raw terephthalic acid solution; (IV)the process of progressively depressurizing and cooling the hydrotreated raw terephthalic acid solution with many crystallizer tanks soas to crystallize and separate the terephthalic acid out; (V)the process of solid-liquid separation of terephthalic acid slurry. The process (II) comprises: at least one process of leading steam produced in process (IV) into heat exchanger to heat raw terephthalic acid slurry; and at least a process of leading high-temperature fluid containing steam and condensed fluid into low-temperature heat exchanger to heat raw terephthalic acid slurry.

Description

technical field [0001] The present invention relates to a method for producing high-purity terephthalic acid, and more specifically relates to the production of high-purity terephthalic acid using vapor generated by depressurization cooling in a crystallization tank and the condensate of the vapor in a heating process method. Background technique [0002] Under pressure, in the presence of an oxidation catalyst such as a catalyst containing cobalt, manganese and bromine in an acetic acid solvent, p-xylene is oxidized in a liquid phase by a gas containing molecular oxygen to remove terephthalic acid (hereinafter In addition to "TA"), crude terephthalic acid (hereinafter referred to as "CTA") containing 4-carboxybenzaldehyde (hereinafter referred to as "4-CBA") as a main impurity is produced. However, in the production of polyester fibers and the like, the raw material used is required to be high-purity terephthalic acid (hereinafter referred to as "PTA"), and therefore, the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/43C07C63/26
CPCY02P20/10Y02P20/50
Inventor 西山良谷口宪生
Owner MITSUI CHEM INC
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