Method for recycling PTA oxidation residue

A residue and oil phase technology, applied in the field of recycling of PTA oxidation residues, can solve the problems of low recovery efficiency, difficulty and low industrial feasibility, and achieve the effect of reducing the discharge of waste residue and protecting the environment.

Active Publication Date: 2015-03-18
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, it is very difficult to recover all components one by one by separation and purification. The existing patented technologies are all developed for a specific composition of TA waste residue, and the mentioned target pure substances with recovery value are generally only one to two species, and there are problems such as high separation cost and low recovery efficiency, the feasibility of industrial implementation is not high

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  • Method for recycling PTA oxidation residue
  • Method for recycling PTA oxidation residue
  • Method for recycling PTA oxidation residue

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036]The PTA oxidation residue A treated in this example comes from the crude terephthalic acid (CTA) mother liquor removal system of the PTA plant, and its main composition (dry basis) is shown in Table 1.

[0037] Table 1. Main composition of PTA oxidation residue

[0038]

[0039]

[0040] Get 99.5 grams of residue A and 101.3 grams of water into a 1000ml three-necked flask with stirring and reflux, and add 196.4 grams of p-xylene extractant simultaneously (the mass ratio of residue, water and extractant in the batching is maintained at about 1:1: 2), then place it in a water bath at 81°C for heating, seal it, turn on the stirring and cooling water. After the slurry temperature of the residue, water, and p-xylene mixture is raised to 80±1.0° C., stir at constant temperature for 1 hour. The obtained liquid / solid / liquid three-phase slurry was filtered at a room temperature of 25° C., and the filter cake was washed with water and p-xylene at a room temperature of 25° C...

Embodiment 2

[0043] The PTA oxidation residue treated in this example is residue B, and its main composition (dry basis) is shown in Table 1. The PTA oxidation residue was extracted in a similar manner to Example 1, and the ingredients were composed of: 100.4 grams of residue B, 101.1 grams of water, and 203 grams of p-xylene (the mass ratio of ingredients was also maintained at about 1:1:2). The difference from Example 1 is that the heating method used in this example is oil bath heating, the temperature of the oil bath is controlled at 105° C., and the extraction temperature is controlled at greater than 100° C. and stirred for 1 hour. The solid samples, oil phase filtrate samples and water phase filtrate samples were taken, and the components were quantitatively analyzed respectively, and the obtained results are listed in Table 2 and Table 3.

Embodiment 3

[0045] The PTA oxidation residue treated in this example is residue B, and the extraction treatment of the PTA oxidation residue is carried out in a manner similar to that of Example 1, and the extraction temperature is also controlled at 80±1.0°C. Different from Example 1, this example uses toluene as the extractant. The composition of ingredients is: 80.6 grams of residue B, 79.8 grams of water and 241.0 grams of toluene, and the quality of ingredients is maintained at 1:1:3. The solid samples, oil phase filtrate samples and water phase filtrate samples were taken, and the components were quantitatively analyzed respectively, and the obtained results are listed in Table 2 and Table 3.

[0046] Table 2. Aromatic carboxylic acid composition comparison of each sample in different embodiments

[0047]

[0048] Table 3. The recovery rate (wt%) of each main component in each phase

[0049]

[0050] From the results of Examples 1 to 3, it can be seen that the efficient sepa...

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Abstract

The invention discloses a method for recycling a PTA oxidation residue. The method sequentially comprises the following steps: 1) mixing the PTA oxidation residue, water and an oil-phase extracting agent, pulping for 0.1-5 hours, and then extracting for 0.1-5 hours at 20-200 DEG C, so as to obtain a material of which a soil phase, an oil phase and a water phase are separated from one another; 2) respectively separating the solid phase, the oil phase and the water phase of the material obtained in the step 1); 3) rectifying the oil phase obtained in the step 2), respectively obtaining benzoic acid and p-toluylic acid, and recycling the rectified oil phase; 4) re-crystallizing the solid phase which is obtained in the step 2) to obtain a mixture of isophthalic acid and terephthalic acid; and 5) removing cobalt and manganese metal ions catalysts from the water phase which is obtained in the step 2), carrying out flash separation on aromatic acid, recycling the processed water phase. Through the method, a PTA oxidation residue system can be recycled; and the components of benzoic acid, isophthalic acid, terephthalic acid and p-toluylic acid can be recycled.

Description

technical field [0001] The invention relates to a method for recycling PTA oxidation residue. Background technique [0002] Terephthalic acid is an important chemical raw material, mainly used in the production of polyester fibers, polyester materials, plasticizers and dyes. At present, the production of terephthalic acid adopts the catalytic oxidation of p-xylene (US2833816, US4243636), and the obtained crude terephthalic acid (CTA) is refined to obtain a terephthalic acid product with a purity that meets the requirements. In the production process, in order to control the impurity concentration of CTA, a part of the circulating reaction mother liquor will be extracted for impurity removal and purification treatment (US4939297, CN200410045270). After recovering acetic acid and catalyst, the purified terephthalic acid (PTA) oxidation residue is obtained. The residue mainly contains components such as benzoic acid, terephthalic acid, isophthalic acid, phthalic acid, trimelli...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/42C07C51/47C07C63/06C07C63/24C07C63/04C07C63/26
Inventor 堵文斌包秀秀成有为李晓强陈韶辉柏基业李希
Owner CHINA PETROLEUM & CHEM CORP
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