Recycling method for pure terephthalic acid industrial wastewater

A technology of purified terephthalic acid and terephthalic acid, which is applied in the field of recycling waste water from the production of purified terephthalic acid, can solve the problems of high investment and operation costs, large floor space, waste of water resources, etc., and achieve investment And the effect of low operation and maintenance costs, reduced discharge of waste water, and reduced consumption of raw materials

Active Publication Date: 2011-08-03
ZHEJIANG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The present invention aims at the disadvantages of low treatment efficiency, large floor area, waste of a large amount of water resources, high investment and operation costs, and low economic benefits in the prior art, and provides a recyclable water treatment with high efficiency, low cost and low cost. Recycling and Utilization Method of Purified Terephthalic Acid Production Wastewater with Simple Operation

Method used

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  • Recycling method for pure terephthalic acid industrial wastewater
  • Recycling method for pure terephthalic acid industrial wastewater
  • Recycling method for pure terephthalic acid industrial wastewater

Examples

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Embodiment 1

[0047] A method for recycling purified terephthalic acid production wastewater, comprising the following steps:

[0048] Step a: removing the solid organic aromatic carboxylic acid in the purified terephthalic acid production wastewater by microfiltration, and returning the filtered solid aromatic carboxylic acid to the oxidation unit;

[0049] Step b: PTA production wastewater and p-xylene are pumped to the membrane extraction unit, the water phase and the oil phase pass through the porous organic membrane on both sides of the membrane module respectively, and the pressure of the wastewater phase containing aromatic carboxylic acid is kept slightly higher than For the p-xylene extraction phase, the wastewater and p-xylene phases are contacted and mass-transferred in the membrane module in a countercurrent, co-current or fully mixed flow mode, and most of the aromatic carboxylic acids in the wastewater are extracted and carried out by the p-xylene extractant;

[0050] Step c: tr...

Embodiment 2

[0062] A method for recycling purified terephthalic acid production wastewater, using the same purified wastewater as in Example 1 to carry out a common liquid-liquid extraction experiment. Take 300ml of waste water and 100ml of p-xylene (PX) in a 500ml separating funnel, vibrate vigorously and mix them, let stand in a constant temperature water bath at 40°C for 24 hours, take the lower layer of water for HPLC and GC analysis, and compare the analysis results shown in Table II.

Embodiment 3

[0064] A method for recycling purified terephthalic acid production wastewater, using the same purified wastewater as in Example 1 to perform a similar membrane extraction experiment. Keep all the operating conditions the same as in Example 1, except that the p-xylene (PX) extraction phase used contains 2000ppm p-toluic acid. After 4 hours of continuous operation, the outlet water of the membrane extraction module was taken for HPLC and GC analysis, and the comparison of the analysis results is shown in Table 2.

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Abstract

The invention relates to the technical field of chemical engineering mass-transfer and separation and discloses a recycling method for pure terephthalic acid industrial wastewater, which comprises the following steps: firstly, solid organic aromatic carboxylic acid in the pure terephthalic acid industrial wastewater is removed through micro-filtration, and the solid organic aromatic carboxylic acid returns to an oxidation unit; filtered wastewater and extractant p-xylene (PX) are respectively delivered to a membrane extraction component by a pump so as to keep water phase pressure slightly higher than PX extraction phase; the PX extraction phase which undergoes membrane extraction is delivered to the oxidization unit to be used as PX raw material of oxidation reaction; after metal ions ofwater phase which undergoes membrane extraction are absorbed and recycled by resin, water phase can return to a refining unit to be used as refined raw material water; in order to prevent other impurities from accumulating in a system, part of pure terephthalic acid industrial wastewater needs to be extracted and sent into a wastewater treatment unit. The recycling method can substantially reducewastewater emission, realize regeneration and utilization of water resources, also can recycle aromatic carboxylic acid, reduce raw material consumption of the process and have the advantages of highefficiency, lower investment and the like.

Description

technical field [0001] The invention relates to the technical field of chemical mass transfer and separation, in particular to a method for recycling purified terephthalic acid production wastewater. Background technique [0002] Purified terephthalic acid (PTA) is an important raw material for the production of polyester (PET), which is mainly produced by air-liquid-phase catalytic oxidation of p-xylene (PX). First, the crude terephthalic acid (CTA) product produced by oxidation of PX, CTA is dissolved in water at 250-300°C, and undergoes processes such as palladium-carbon (Pd / C) catalytic hydrogenation, multi-stage crystallization, and solid-liquid separation. Purified terephthalic acid (PTA) products are obtained. Since water is used as a solvent in the PTA refining process, a large amount of wastewater containing aromatic carboxylic acids will be produced, and wastewater treatment has always been a problem that needs to be solved urgently in the PTA process. [0003] A...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04
Inventor 成有为孔庆然倪宾李希陈欢林陈国斌
Owner ZHEJIANG UNIV
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