| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a system that enables the reuse of a used aqueous medium by a convenient structure, and the usage of a new aqueous medium is reduced in the purification method of crude terephthalic acid. <P>SOLUTION: The purification method of crude terephthalic acid is characterized as follows. Treatment effluent includes: condensed water produced by cooling vapor generated in a pressure discharge operating period; scrubber treated waste water produced by cleaning gas separated from the condensed water and exhaust gas from a circulation/seal gas from machineries of a solid separation vessel or the like and tanks of a mother liquid or the like, by using an aqueous medium; and cleaning drain produced by cleaning and fractionation-recovering a solid obtained in the solid-liquid separation. At least one of the treatment effluent is added with crude terephthalic acid crystal to be suspension and then is subjected to solid-liquid separation to recover separation crystal and separated water. The separation crystal is used as a part of a raw material at production of the crude terephthalic acid, and the separated water is used as at least a part of an aqueous medium that dissolves the crude terephthalic acid. <P>COPYRIGHT: (C)2013,JPO&INPIT |
