Process for producing terephthalic acid and device therefor

Abstract

The invention discloses a method for producing terephthalic acid (TA) and its device. The device is composed of three parts: bubble column reactor, slurry treating device, and exhaust gas treating device. The method is provided as follows: Adopting bubble column reactor with gas separating zone for liquid phase catalytic oxidation of xylene; adopting multistage vaporization, filtering and drying in slurry treating device for recovering solid TA; adopting multistage condensation of byproduced steam for recovering reaction heat in the exhaust gas treating device and recovering solvent by using azeotropy rectification method; determining related process conditions according to the demand of minimum production cost.

Description

technical field [0001] The invention relates to a production method and device for producing terephthalic acid (TA). Background technique [0002] Terephthalic acid is an important raw material for the production of polyester (PET) fibers and resins. At present, it is mainly produced by the p-xylene air oxidation method. Or tetrabromoethane) in the acetic acid solvent, pass into air or enriched oxygen to carry out oxidation, generate solid product terephthalic acid. The typical reaction temperature is 155-205°C, the pressure is 0.5-1.6MPa, and the residence time is 40-120min. The reaction heat is removed by solvent evaporation, and the steam is condensed and returned to the reactor. The resulting slurry is then obtained through subsequent separation and refining processes. Purified terephthalic acid (PTA) products. [0003] The production process of TA includes three main parts: reaction unit, tail gas treatment unit and slurry treatment unit. The tasks and functions of ea...

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Problems solved by technology

But above-mentioned method is somewhat difficult to implement, and for example patent US5723656 and US6143925 introduce and finish the task of all acetic acid dehydration by a rectification tower that is connected with bubble column reactor and just require separation equipment very huge, because the temperature pressure of reaction tail gas is higher , also contains a large amount of inert gas

On the other hand, the various patented technologies currently disclosed are partial energy-saving measures. Although they may have a certain energy-saving effect on some units and equipment after implementation, it is difficult to achieve the goal of the lowest energy consumption in the entire process.

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