| 摘要 |
PURPOSE: To provide a method for finally producing high-purity terephthalic acid, not installing a plate, etc., in a dispersion medium substitution column, subjecting a raw slurry consisting essentially of terephthalic acid crystal and a raw dispersion medium (a dispersion medium for liquid-phase oxidation reaction or a dispersion medium for purification treatment after the reaction) to dispersion medium substitution while pouring a dispersion medium for substitution from the lower part of the bottom of the column. CONSTITUTION: A raw slurry consisting essentially of terephthalic acid crystal particles obtained by liquid-phase oxidation or purification treatment after the liquid-phase oxidation and a raw dispersion medium is fed from the upper part of a dispersion medium substitution column and a dispersion medium for substitution is supplied from the lower part of the column, the solution at the lower part of the column is stirred into a scurried state uniformly as much as possible, the flow rate in supply of the dispersion medium for substitution and that in taking out the substituted slurry are regulated, both the solutions are brought into contact with each other in a liquid-liquid state while maintaining a slurry state in a concentration higher than that in the middle part of the column. The prepared substituted slurry is taken out from the bottom of the column, the liquid at the middle part of the dispersion medium substitution column is divided into plural flows in parallel or not divided to provide a method for producing high-purity terephthalic acid. |
