TH49673A - The process for producing aromatic carboxylic acid. - Google Patents

Abstract

DC60 (21/07/43) This process efficiently produces aromatic carboxylic acid by using a distillation column to separate the volatile solvent of the reaction of other useful components from the oxidation reactor, while simultaneously recovering energy efficiently without causing any obstruction to the turbine or clogging of the distillation column. The process involves oxidizing alkyl aromatic compounds in the solvent of the liquid phase reaction containing aliphatic carboxylic acid with oxygen-containing gas in the presence of a catalyst in the oxidation reactor to form aromatic carboxylic acid. The used gas from the oxidation reactor is then fed into the distillation column for distillation. The upper part of the distillation gas passes through the condenser to form condensate, which is returned to the distillation column to produce bulb steam. This steam is then fed to a steam turbine for energy recovery. The combustion of gases exiting the condenser drives a gas turbine for energy recovery. This process efficiently produces aromatic carboxylic acid by using a distillation column to separate the volatile solvent of the reaction of other useful mixtures from the oxidation reactor, while simultaneously recovering energy efficiently without obstructing the turbine or clogging the distillation column. This process involves oxidizing alkyl aromatic compounds in the solvent of the liquid phase reaction containing aliphatic carboxylic acid with oxygen-containing gas in the presence of a catalyst in the oxidation reactor to form aromatic carboxylic acid. The used gases from the oxidation reactor are then fed into the distillation column for distillation. The upper part of the distillation gas passes through the condenser to form condensate, which is returned to the distillation column to produce bulb steam. This steam is then fed to a steam turbine for energy recovery. And the gases exiting the condenser are burned to drive the gas turbine for energy recovery.

Claims (11)

1. The process for producing aromatic carboxylic acid involves the oxidation of alkyl aromatic compounds in the liquid phase with oxygen-containing gas under high temperature/pressure conditions in an oxidation reactor. This reactor consists of several steps: Oxidation, where the alkyl aromatic compounds in the reaction solvent in the liquid phase containing aliphatic carboxylic acid are oxidized with oxygen-containing gas. A catalyst accelerates the oxidation reaction to form aromatic carboxylic acid. Distillation, where the used gas from the oxidation reactor is fed into a distillation column for distillation. The resulting liquid containing the reaction solvent is returned to the oxidation reactor. Condensation, where the gas at the top of the distillation column is cooled in a condenser to form condensate. This condensate is then returned to the distillation column to produce steam. Combustion, where the gas exiting the condenser is burned in a combustion chamber. Finally, energy recovery, where energy is recovered from the oxidation process. The amount of heat generated by the steam in the condenser and by the combustion gases in the combustion chamber. 2. The process described in Claim 1 consists of an absorption step in which low-boiling point aliphatic carboxylic acid esters are collected in the condensation phase. The condensing gases and condenser exit gases are introduced into contact with an aliphatic carboxylic acid absorption liquid that will absorb the aliphatic carboxylic acid esters. The absorbed aliphatic carboxylic acid absorption liquid is then transferred to an oxidation reactor, while the delivery gas from the absorption step is combusted in a combustion chamber. 3. The process under claim 1 or 2 consists of the following step: gas leaching, in which the gas delivered in the absorption step is brought into contact with the leaching water to absorb the aliphatic carboxylic acids present therein. 4. One of the processes described in Claims 1 through 3 shall maintain the temperature of the condenser outlet gas within the range of 50 to 150 °C in order to keep methyl acetate within the outlet gas. 5. Any of the processes described in Claims 1 through 4 in which energy recovery is achieved using steam turbines and gas turbines. 6. One of the processes described in Claims 1 through 5 involves delivering a gas containing oxygen molecules to an oxidation reactor under compression, using recovered energy. 7. One of the processes described in Claims 1 through 6 shall provide a portion of the liquid extraction on a distillation column. 8. One of the processes described in Claims 1 through 7 in which a distillate is extracted from the bottom distillation column and this distillate is used as an absorbent liquid. 9. Any process under Claims 1 through 8 shall be connected to a distillation column to immediately return the distillate from the bottom of the column to the external system. 10. Any process under claims 1 through 9 in which the condensation step can be achieved using multiple condensers in sequence. 11. Any process under claims 1 through 10 where the condenser is of the kettle type.