FIELD: chemistry.
SUBSTANCE: first method involves a) producing in an oxidation reactor, a raw aromatic polycarboxylic acid flow as an oxidation reaction product and an oxidation reactor exhaust gas flow, separating the exhaust gas flow into an acetic acid-enriched flow and a water-enriched vapour flow, where the water-enriched vapour flow contains volatile compounds and non-condensed gases; the separation procedure is performed in a distillation unit; b) condensing the above water-enriched vapour flow into a condensate flow and a vapour flow; c) supplying a first portion of the above condensate flow into the above distillation unit and supplying a second portion of the above condensate flow into an extraction column, and d) removing at least one aromatic monocarboxylic acid from the above second portion of the above condensate to generate a aromatic monocarboxylic acid flow and an aqueous product flow. A second method involves a) adding paraxylol, molecular oxygen and acetic acid into an oxidation reactor and stirring; producing in the oxidation reactor, a raw terephthalic acid flow as an an oxidation reaction product; b) removing reactor exhaust gas from the above oxidation reactor, where the above reactor exhaust gas contains acetic acid and water vapour; c) supplying the above reactor exhaust gas into a distillation column, where the reactor exhaust gas is separated into an acetic acid-enriched flow, which is supplied back to the above oxidation reactor, and a water-enriched vapour flow, which is supplied to a condenser; d) condensing the above water-enriched vapour flow into a condensate flow and a vapour flow, where a first portion of the above condensate flow is supplied back to the above distillation column, and a second portion of the above condensate flow is supplied to an extraction column; e) supplying the above vapour flow into an absorber to remove volatile components from the vapour; f) supplying into the above extraction column, a paraxylol counter-flow to the above second portion of the above condensate flow; g) recovering aromatic monocarboxylic acid from the above second portion of the above condensate flow to generate a water flow, and supplying aromatic monocarboxylic acid into the above oxidation reactor; h) supplying the above water flow into a water treatment column to remove volatile components, where the volatile components are recovered in the form of vapour and condensed to generate irrigation; i) supplying a first portion of the above irrigation back to the above water treatment column and supplying a second portion of the above irrigation back to the above oxidation reactor; and j) supplying vapour to a base of the water treatment column to remove the remained volatile components, to generate a pure water flow, considerably free from contaminants.
EFFECT: lower expenses and higher yield.
18 cl, 1 dwg, 1 tbl, 3 ex
