METHOD FOR PRODUCING HIGH-PURITY TEREPHTHALIC ACID

摘要

PROBLEM TO BE SOLVED: To enable long-term stable production of terephthalic acid without temporarily stopping a production plant of terephthalic acid and carrying out washing of production plant by ensuring sure motion of a slurry treating apparatus in crystallization step without causing local deposition of slurry. SOLUTION: The method for producing high-purity terephthalic acid comprises evaporating water which is a solvent for slurry by carrying out cooling by release of pressure in a crystallization tank 1, bringing the temperature of the solvent vapor near operation temperature of the crystallization tank by heating a sealing liquid as much as possible by a heater 7 using the solvent vapor as a heating source and feeding the solvent vapor to a conduit 9b of a level gage 9 and a stirring bearing 5 to suppress deposition of terephthalic acid in a local part of slurry. As a result, the slurry treating apparatus enables sure motion and is free from troublesome step for temporarily stopping the production plant of terephthalic acid and washing the production plant and enables long-term stable production of high-purity terephthalic acid. COPYRIGHT: (C)2005,JPO&NCIPI