PROCESS FOR CRYSTALLIZATION AND SOLID-LIQUID SEPARATION IN TEREPHTHALIC ACID PREPARATION

摘要

The present invention relates to a process for crystallization and solid-liquid separation to separate a solid-phase terephthalic acid from slurry including the terephthalic acid and reaction intermediates produced via a paraxylene oxidation, wherein the reaction intermediates include a paratoluic acid and a 4-carboxybenzaldehyde. The process comprises filtering the crystallized slurry in a high-temperature high-pressure filter, separating the terephthalic acid in the form of solid, and separating a mother liquid having the reaction intermediates in the form of liquid, characterized in that the operating temperature of the high-temperature, high-pressure filter is 130~220°C and the operating pressure thereof is 10~20kgf/cm2g. The slurry includes paratoluic acid at more than 10 wt %, preferably more than 20 wt %, and the crystallization can be carried out in a crystallization tank.