| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a high purity terephthalic acid at a low cost by which a hydrogenation treatment can be performed at a high efficiency by increasing the concentration of the terephthalic acid, the handling can be facilitated by regulating the concentration of the slurry at the crystallization time to be low, the treatment is carried out by transporting the liquid by utilizing the initial pressure, an apparatuses is miniaturized by decreasing the use of pumps and condensers, and the amount of the used energy is reduced. SOLUTION: CTA(crude terephthalic acid) and water are introduced to a dissolving tank 11, and high-pressure steam is blown from L21 to pressurize the L21. Temperature is raised to 250-350 deg.C and the CTA is dissolved. The obtained aqueous solution is subjected to a hydrogenation treatment by a hydrogenation reactor. The treated liquid is introduced to the 1st or the final crystallizing vessel 3 or 4, and the water at a low temperature is introduced thereto from L22 or L23 to decrease the temperature and to carry out the crystallization. The crystallized slurry is subjected to a solid-liquid separation by the first separator 5. The obtained crystal is formed into a slurry again in a re-slurry tank 6, and the obtained slurry is subjected to the solid-liquid separation by a final separator 7. The obtained crystal is dried by a dryer 8 to provide the objective highly pure terephthalic acid.
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