PRODUCTION OF AN AROMATIC DICARBOXYLIC ACID

The present invention provides a process for the production of a purified aromatic dicarboxylic acid comprising the steps of: i) catalytically oxidizing a hydrocarbon precursor in an organic solvent to form a product stream and a vent gas in an oxidation stage; ii) separating the vent gas from the oxidation stage into an organic solvent-rich liquid stream and a water-rich vapour stream in a distillation stage; iii) condensing the water-rich vapour stream from the distillation stage into a condensate stream and a vapour stream in a first condensation stage by transferring heat from the water-rich vapour stream to a first coolant liquid flowing in a coolant system; and iv) forming a slurry of crude aromatic dicarboxylic acid crystals and an overhead vapour from the product stream from the oxidation stage in a crystallisation stage; and v) purifying the crude aromatic dicarboxylic acid crystals to yield the purified aromatic dicarboxylic acid, characterised in that the process further comprises the steps of: vi) condensing at least a portion of the overhead vapour from the crystallisation stage by transferring heat from the overhead vapour to a second coolant liquid flowing in the coolant system, wherein at least a portion of the second coolant liquid is derived from the first coolant liquid, wherein the condensing of at least a portion of the overhead vapour from the crystallisation stage is conducted in a second condensation stage comprising a first condenser; and vii) measuring the temperature of the second coolant liquid in the coolant system downstream of the first condenser and/or measuring the flow rate of the second coolant liquid in the coolant system; wherein the coolant system is configured to direct at least a portion of the second coolant liquid from a position in the coolant system downstream of the first condenser to a position in the coolant system upstream of the first condenser via a feedback system configured to cool the second coolant liquid if the measured temperature of the second coolant liquid downstream of the first condenser is greater than or equal to a first pre-set temperature and/or the measured flow rate of the second coolant liquid is less than or equal to a pre-set flow rate. The present invention further provides an apparatus for carrying out the process. La présente invention concerne un procédé de production d'un acide dicarboxylique aromatique purifié, le procédé comprenant les étapes consistant à : i) soumettre un précurs