Deep oxidation method and deep oxidation device in the production of polymer grade terephthalic acid

Abstract

The invention relates to a deep oxidation method and a deep oxidation device in KPTA (Kunlun pure terephthalic acid) production; the method comprises the following steps of: (1) oxidizing: oxidizing PX (p-Xylene) with oxygen in solvent HAC (ethanoic acid) in case of catalysis; (2) deeply oxidizing: further deeply oxidizing the slurry obtained in the step (1) through oxidizing with oxygen to improve the TA (terephthalic acid) content; and (3) crystallizing and separating: crystallizing and separating TA from the slurry obtained in the step (2). The system comprises an oxidation reactor, a reactor discharge tank, a deep oxidation reactor and a crystallizing and separating system, wherein a slurry outlet of the oxidation reactor is connected with a slurry inlet of the discharge tank, a slurry outlet of the discharge tank is connected with a slurry inlet of the deep oxidation reactor, and a slurry outlet of the deep oxidation reactor is connected with a slurry inlet of the crystallizing and separating system. The method provided by the invention not only can guarantee the product quality, but also can reduce the requirement on equipment, and stirring equipment is omitted, so that the equipment investment can be reduced, and the power consumption can be effectively reduced.

Description

technical field [0001] The invention relates to a deep oxidation method in the production of KPTA (polymerized grade terephthalic acid of Kunlun Co., Ltd.), and also relates to a deep oxidation device using the method, which belongs to the technical field of chemical industry. Background technique [0002] At present, there are two kinds of technologies for producing terephthalic acid in the world: one is the PTA (purified terephthalic acid) production process, and the device is divided into two parts: an oxidation unit and a hydrofining unit. Under the action of a catalyst, p-xylene (PX) is first oxidized with oxygen in the air in acetic acid (HAC) solvent to generate terephthalic acid (TA) and intermediate products (p-carboxybenzaldehyde 4-CBA, p-toluic acid PT acid, etc.), to prepare crude terephthalic acid (CTA), and then dissolve CTA in water, and reduce 4-CBA to PT acid by hydrogenation reaction. Using the different solubility of PT acid and TA in water, the PT The ac...

AI Technical Summary

Problems solved by technology

The deep oxidation process has the advantages of short process, low investment, and less sewage. However, the traditional deep oxidation reaction process uses a lot of stirring equipment, unreasonable energy utilization, and complicated impurity removal system. There has not been much development in the past two decades, and no new ones have been established. factory

At present, manufacturers that use deep oxidation process to produce TA mostly use stirred tank reactor for oxidation and deep oxidation reactor, which requires high investment and consumes a lot of electric energy.

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