Separative purifying method for terephthalic acid

A terephthalic acid and purification method technology, which is applied in the production field of aromatic carboxylic acids in chemical industry, can solve the problems of filter cloth clogging, prolonging the filter operation period, and not having strict requirements for product quality control

Inactive Publication Date: 2004-12-15
YANGZI PETROCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The existing technology has made a certain breakthrough in the use of rotary suction filter to replace the traditional process, but its focus is

Method used

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  • Separative purifying method for terephthalic acid
  • Separative purifying method for terephthalic acid
  • Separative purifying method for terephthalic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0031] The terephthalic acid slurry coming out of the crystallizer of the PTA refining unit has a temperature of 151°C and a terephthalic acid concentration of 40%. The difference is 0.04MPa. After a series of processes such as filtration, primary drying, washing, and secondary drying, the impurities in the slurry enter the mother liquor solid recovery system with the mother liquor, and the filter cake enters the dryer through the feeding rotary valve operated under pressure. Material screw, the moisture content of the filter cake is 10%. The content of PT acid in the product is 110mg / kgPTA, the average particle size is 118um, and the product quality is obviously better than that of traditional secondary separation.

Embodiment 2

[0033] The terephthalic acid slurry coming out of the crystallizer of the PTA refining unit has a temperature of 160°C and a terephthalic acid concentration of 40%. The difference is 0.05MPa. After a series of processes such as filtration, primary drying, washing, and secondary drying, the impurities in the slurry enter the mother liquor solid recovery system with the mother liquor, and the filter cake enters the dryer through the feeding rotary valve operated under pressure. Material screw, the moisture content of the filter cake is 8%. The content of PT acid in the product is 100mg / kgPTA, the average particle size is 120um, and the product quality is obviously better than that of traditional secondary separation.

Embodiment 3

[0035]The terephthalic acid slurry coming out of the crystallizer of the PTA refining unit has a temperature of 155°C and a terephthalic acid concentration of 40%. The difference is 0.1MPa. After a series of processes such as filtration, primary drying, washing, and secondary drying, the impurities in the slurry enter the mother liquor solid recovery system with the mother liquor, and the filter cake enters the dryer through the feeding rotary valve operated under pressure. Material screw, the moisture content of the filter cake is 7%. The content of PT acid in the product is 97mg / kgPTA, the average particle size is 116um, and the product quality is obviously better than that of traditional secondary separation.

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Abstract

In the continuous pressurized filtering one-stage separation process, the parathalic acid product is obtained through filtering in a pressurized filter, the first drying, washing, secondary drying to form filter cake, back blowing with inert gas to peel off filter cake, discharging via the valve, passing through the feeding screw and drying in the drying machine. The present invention has high product quality and simple separation process.

Description

technical field [0001] The invention belongs to the production technology of aromatic carboxylic acid in chemical industry, and relates to a separation and purification method of terephthalic acid. Background technique [0002] In the process of preparing terephthalic acid (hereinafter referred to as PTA) by air oxidation of p-xylene, there must be a certain concentration of oxidation intermediates and trace colored bodies in the oxidation solution, and the crude terephthalic acid (TA) and The p-carboxybenzaldehyde (4-CBA) intermediate forms a co-crystal, which is brought into the crude terephthalic acid (TA) as an impurity. In order to remove these impurities, the main process of the prior art refining process undergoes high-temperature hydrogenation, crystallization, Separation, parent solid recovery and drying unit. In the separation unit, two-stage separation technology is commonly used. The first stage is pressure centrifugal separation. The slurry comes out of the crys...

Claims

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Application Information

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IPC IPC(8): C07C51/43C07C63/26
Inventor 王振新黄树军吴省安王建平移素鸿
Owner YANGZI PETROCHEM
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