System and method for improving water quality of dehydration tower in purified terephthalic acid device

A treatment system for improving the water quality of a dehydration tower in a purified terephthalic acid device, the system comprising a dehydration washing device, a tail gas condensation device communicating with a top of the dehydration washing device, and a water separation device communicating with the tail gas condensation device, wherein:

• the dehydration washing device comprises a first-stage purified water washing unit located at the top of the dehydration washing device, a second-stage concentrated water washing unit located in the middle of the dehydration washing device, and/or a third-stage refined mother liquor washing unit located at a lower portion of the dehydration washing device;
• the tail gas condensation device comprises oxidized tail gas condensers;
• the tail gas condensation device is connected with a first high-temperature condensed liquid tank for containing a first condensed liquid obtained after a first heat exchange by the oxidized tail gas condensers in the system, a second condensed liquid tank for containing a second condensed liquid obtained after a second heat exchange, and a second vapor channel for exporting vapor;
• and
• the water separation device comprises multi-effect evaporation units for purifying and separating the second condensed liquid, as well as a purified water outlet and a concentrated water outlet, wherein the multi-effect evaporation units comprise a first-effect evaporation unit and a second-effect evaporation unit, the purified water outlet communicates to the first-stage purified water washing unit through a purified water pipeline, the second condensed liquid tank communicates to the bottom of the first-effect evaporation unit through a second condensed liquid pipeline to separate the second condensed liquid, and the second vapor channel extends into the first-effect evaporation unit through a second vapor pipeline to provide a heat source for heat exchange during the separation of the second condensed liquid;
• the concentrated water outlet communicates to the second-stage concentrated water washing unit through a concentrated water pipeline;
• and
• a purified water heat exchanger is disposed on the purified water pipeline, the first high-temperature condensed liquid tank conducts heat exchange by the purified water heat exchanger through a high-temperature condensed liquid pipeline, a concentrated water heat exchanger is disposed on the concentrated water pipeline, and the first high-temperature condensed liquid tank conducts heat exchange by the concentrated water heat exchanger through a second high-temperature condensed liquid pipeline.