Kvaerner Process Technology, Ltd.

Richard Clive Spratt

George E Harrison

Arthur James Reason

The invention proposes a process and waste treatment plant for regenerating alkali metal hydroxide (,) from an alkaline aqueous waste stream (,) that contains alkali metal C3&plus; carboxylate byproduct. The waste stream (,) is acidified and the resulting liquour (,) is fed to a first distillation zone (,) to distil carboxylic acid and water. Alternatively, it is fed to a settling zone (,) from which an upper organic layer (,) is recovered as well as a lower aqueous phase (,) which is fed to the first distillation zone. The overhead product (,) from the first distillation zone is condensed and separated into a carboxylic acid layer which is either purged (,) or fed (,) to the settling zone (,). The lower layer (,) of the condensate is redistilled and the water bottoms stream (,) is fed to the cathode compartment (,) of an electrolytic cell (,), while the bottoms stream (,) from the first distillation zone is supplied to the anode compartment (,). Inorganic acid (,) regenerated in the anode compartment is used to acidify the waste stream, while alkali metal hydroxide solution from the cathode compartment is recycled to the chemical production plant (,).

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Harrow, United Kingdom

Richard Clive Spratt