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Method for washing crude terephthalic acid filter cake

A technology of crude terephthalic acid and washing method, which is applied in the field of washing of crude terephthalic acid filter cake, and can solve the problem of high content of p-xylene

Active Publication Date: 2015-02-11
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is the problem that the residual p-xylene content in the crude terephthalic acid filter cake is too high in the prior art, and a kind of washing method of the crude terephthalic acid filter cake is provided, which has the advantages of crude p-xylene The residual p-xylene content in the phthalic acid filter cake is low, and it has good compatibility with the subsequent hydrofining process and polymerization process

Method used

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  • Method for washing crude terephthalic acid filter cake
  • Method for washing crude terephthalic acid filter cake
  • Method for washing crude terephthalic acid filter cake

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] 8 kg of acetic acid slurry containing 36% crude terephthalic acid in terms of weight percent concentration from the oxidation reactor is filtered in a filter to obtain a thick terephthalic acid filter cake containing 10% of acetic acid in weight percent . Then, wash the crude terephthalic acid filter cake with 1.5 times the weight of the crude terephthalic acid filter cake and be heated to 70°C for beating and washing the crude terephthalic acid filter cake, and filter to obtain a p-xylene containing 8% by weight percentage. Crude Terephthalic Acid Cake I.

[0012] Use the sodium lauryl sulfate aqueous solution of 0.5% concentration by weight to carry out beating and washing according to the weight equivalent to 1.5 times of the terephthalic acid filter cake I, then filter and analyze the acetic acid and p-xylene in the filter cake II obtained by sampling content, and the results are shown in Table 1.

[0013] In order to check the impact of residual surfactant on the...

Embodiment 2～22

[0016] Except that the type of surfactant, the concentration of surfactant and the amount of washing liquid are different, other operating conditions are all the same as in Example 1. The changes in operating conditions and the experimental results are shown in Table 1. The tensio-active agent shown in formula III used in the embodiment is produced by BASF company A series of surfactants, in which (CH(CH 3 )CH 2 O) y The molar mass of the chain segment and -CHCH in the molecule 2 The O-group content is shown in Table 2.

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Abstract

The invention relates to a method for washing a crude terephthalic acid filter cake, and the method is mainly used for solving the problem of overhigh residual paraxylene content of the crude terephthalic acid filter cake of the prior art. The method comprises the following steps of: (a) washing crude terephthalic acid containing acetic acid with paraxylene and filtering so as to obtain a filter cake I; and (b) washing the filter cake I with an aqueous solution containing a surface active agent shown in a formula III, and filtering to obtain a filter cake II, wherein the molar mass of a y chain in (CH(CH3)CH2O) of the surface active agent is between 900 and 3300, and a base group of -CHCH2O- accounts for 10-80% in weight percent. The method can be utilized for better solving the problem and used for crude terephthalic acid industrial production. HO(CH2CH2O)x(CH(CH3)CH2O)y(CH2CH2O)zH (III).

Description

technical field [0001] The invention relates to a washing method of crude terephthalic acid filter cake. Background technique [0002] Terephthalic acid is usually obtained by liquid-phase oxidation of p-xylene in acetic acid solvent with Co-Mn-Br as a catalyst. The crude terephthalic acid obtained by the above method needs further hydrofining to remove p-carboxybenzaldehyde (4-CBA), p-toluic acid (PT acid) and some colored impurities to obtain purified terephthalic acid. Before hydrofining, the acetic acid in the crude terephthalic acid slurry must be removed to prepare a terephthalic acid aqueous slurry. The traditional process is to remove the acetic acid in the crude terephthalic acid mother liquor by centrifugal filtration and drying equipment, and then beat with water to obtain a terephthalic acid water-based slurry. The drying process of this process consumes a lot of energy and the cost of the drying equipment is high. . [0003] In order to solve the above proble...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C63/26C07C51/42
Inventor 朱庆才畅延青陈大伟
Owner CHINA PETROLEUM & CHEM CORP
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