Process for producing aromatic carboxylic acid

A process for producing aromatic carboxylic acid by a liquid phase oxidation of an alkyl aromatic compound with a molecular oxygen-containing gas under a high temperature/high pressure condition in an oxidation reactor, comprising

• an oxidation step in which the alkyl aromatic compound is oxidized in a liquid reaction solvent comprising an aliphatic carboxylic acid with the molecular oxygen-containing gas in the oxidation reactor in the presence of an oxidation catalyst to form an aromatic carboxylic acid,
• a distillation step in which the exhaust gas from the oxidation reactor is guided to a distillation column to subject it to distillation therein and liquid fractions formed therein containing the reaction solvent are returned to the oxdation reactor,
• a condensing step in which the distillation column overhead gas is cooled in a condenser so as to form a condensate which is returnd to the distillation column and to generate a steam in the condenser,
• a burning step in which the condenser exit gas is burnt in a burning chamber and
• an energy recovering step in which energy is recovered from the heat contents of the steam generated in the condenser and of the combustion gas formed in the burning chamber.