Terephthalic Acid (TPA)-Fiber Grade

Abstract

Para-xylene and fresh acetic acid are mixed with catalyst and recycled acetic acid. The feed stream is pumped to the top of the oxidation reactor while the air enters through the bottom of the reactor. Temperature and pressure in the reactor are held at 2000C and 14 bar respectively. Reaction time is half to one hour. The reactor products are continuously discharged as a hot slurry into a crystalliser where cooling takes places by flashing off part of acetic acid, unreacted p-xylene and water of reaction _ The slurry is then sent to a centrifuge. The crude TPA is dried and further purified to fibre grade TPA by means of hydrogenation. The liquid from the centrifuge is sent to acetic acid recovery for recycle.