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US 7,452,522 B2Granted
Extraction process for removal of impurities from an oxidizer purge stream in the synthesis of carboxylic acid
AssigneeEastman Chemical Company
InventorsRobert Lin, Marcel de Vreede
Life of this patent
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Abstract
Disclosed is a process that relates to the recovery of a metal catalyst from an oxidizer purge stream produced in the synthesis of carboxylic acid, typically terephthalic acid. The process involves the addition of a wash solution to a high temperature molten dispersion to recover the metal catalyst and then subjecting an aqueous mixture or purified aqueous mixture so formed to a single stage extraction to remove organic impurities to produce an extract stream and a raffinate stream comprising the metal catalyst.
Claims14
A process comprising:
- (a) subjecting an oxidizer purge stream comprising a carboxylic acid, a metal catalyst, impurities, water and a solvent to evaporation in a first evaporator zone to produce a vapor stream and a concentrated purge slurry;
- and
- (b) subjecting said concentrated purge slurry to evaporation in a second evaporator zone to produce a solvent rich stream and a high temperature molten dispersion;
- wherein about 95 wt % to about 99 wt % of said solvent and water present in said oxidizer purge stream from step (a) is removed and wherein said second evaporator zone comprises an evaporator operated at a temperature of about 150° C. to about 200° C.;
- (c) mixing in a mixing zone a wash solution with said high temperature molten dispersion to form an aqueous mixture;
- (d) adding an extraction solvent to said aqueous mixture in an extraction zone to form an extract stream and a raffinate stream;
- and
- (e) separating said extract stream and said solvent rich stream in a separation zone to form a high boiling point organic impurities stream.
5 more elements
A process comprising:
- (a) subjecting an oxidizer purge stream comprising a carboxylic acid, a metal catalyst, impurities, water and a solvent to evaporation in a first evaporator zone to produce a vapor stream and a concentrated purge slurry;
- and
- (b) subjecting said concentrated purge slurry to evaporation in a second evaporator zone to produce a solvent rich stream and a high temperature molten dispersion;
- wherein about 95 WT % to about 99 wt % of said solvent and water present in said oxidizer purge stream from step (a) is removed;
- and wherein said second evaporator zone comprises an evaporator operated at a temperature of about 150° C. to about 200° C.;
- (c) mixing in a mixing zone a wash solution with said high temperature molten dispersion to form an aqueous mixture;
- (d) separating organic impurities from said aqueous mixture in a solid-liquid separation zone to form a purified aqueous mixture;
- (e) adding an extraction solvent to purified aqueous mixture in an extraction zone to form an extract stream and a raffinate stream;
- and
- (f) separating said extract stream and said solvent rich stream in a separation zone to form a high boiling point organic impurities stream.
7 more elements
Dependencies are inferred from the claim text.