Bromide ion recovery processing method and device in PTA (pure terephthalic acid) production

The method of filtration, ion exchange and distillation concentration of terephthalic acid production exhaust alkaline washing liquid was successfully improved, the recovery rate of bromide ions was solved, the problem of hydrobromic acid was not effectively recovered, the production cost was reduced and the possibility of environmental protection was increased.

CN119656825APending Publication Date: 2025-03-21XINJIANG KORLA ZHONGTAI PETROCHEMICAL CO LTD
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Patent Information

Application Number
CN202411270401.9
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2024-09-11
Publication Date
2025-03-21

AI Technical Summary

Technical Problem

In the existing production of phthalic acid, after hydrobromic acid is used as a promoter, some bromine ions are lost to the exhaust gas and are unable to be effectively recycled and reused, resulting in high production costs and difficult to achieve environmental protection standards.

Method used

After filtering the exhaust alkaline wash solution, add sodium hydroxide solution to adjust the pH value to form a sodium carbonate solution. Then, use the nanofiltration membrane and the resin bed to perform ion exchange, remove salt ions, and finally concentrate through the distillation membrane device to obtain high concentration of hydrobromic acid and reuse it to the mother liquor system.

Benefits of technology

It realizes efficient recycling of bromide ions in the exhaust alkaline wash solution, and the recovery rate can reach more than 85%, reducing production costs and increasing the possibility of environmental protection compliance.

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Abstract

The invention relates to the technical field of terephthalic acid production post-treatment, in particular to a bromine ion recovery treatment method and device in PTA (pure terephthalic acid) production, in the previous method, after impurities in tail gas alkali wash are filtered out, a sodium hydroxide solution is introduced, the pH value of the solution is adjusted, the tail gas alkali wash is subjected to nanofiltration, a weak cation resin bed layer and a strong cation resin bed layer to remove salt ions in the solution, and the tail gas alkali wash is subjected to purification treatment; the dilute hydrobromic acid solution comprises a filter, a sodium carbonate conversion tank, a nanofiltration membrane device, a weak cation resin bed layer, a strong cation resin bed layer, a dilute hydrobromic acid heater, a hydrobromic acid tank, a distillation membrane device, a sewage storage tank, a sewage cooler and a hydrochloric acid storage tank. Hydrobromic acid is recovered through separation of nanofiltration and distillation technologies, the purpose of recovering bromide ions in wastewater is achieved, safe, stable and efficient operation of the bromide ion recovery treatment device is guaranteed, and the production cost is reduced.
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