Processes for Producing Acetic Acid

A process for removing permanganate reducing compounds (PRC's) from a crude acetic acid composition comprising acetic acid and one or more PRC's, the process comprising the steps of:

• (a) separating the crude acetic acid composition in a light ends column into a PRC enriched stream and an acetic acid stream;
• (b) separating the PRC enriched stream into an aqueous phase and an organic phase;
• (c) separating the aqueous phase in a distillation column into an overhead stream and a bottoms stream;
• (d) extracting at least a portion of the overhead stream with an extraction medium in an extraction unit to form a PRC extracted stream and a raffinate;
• and
• (e) directing a first return stream comprising at least a portion of the raffinate to the light ends column.

A process for removing permanganate reducing compounds (PRC's) from a crude acetic acid composition comprising acetic acid and one or more PRC's, the process comprising the steps of:

• (a) separating the crude acetic acid composition in a light ends column into a PRC enriched stream and an acetic acid stream;
• (b) separating the PRC enriched stream into an aqueous phase and an organic phase;
• (c) separating the aqueous phase in a distillation column into an overhead stream and a bottoms stream;
• (d) distilling the acetic acid stream in a drying column to form a water stream and an acetic acid product stream;
• and
• (e) directing a first return stream comprising at least a portion of the bottoms stream to the drying column.

A process for removing permanganate reducing compounds (PRC's) from a crude acetic acid composition comprising acetic acid and one or more PRC's, the process comprising the steps of:

• (a) separating the crude acetic acid composition in a light ends column into a PRC enriched stream and an acetic acid stream;
• (b) separating at least a portion of the acetic acid stream in a drying column to form a water stream and an acetic acid product stream;
• (c) separating the PRC enriched stream into an aqueous phase and an organic phase;
• (d) separating the aqueous phase in a distillation column into an overhead stream and a bottoms stream;
• (e) extracting at least a portion of the overhead stream with an extraction medium to form a PRC extracted stream and a raffinate;
• (f) directing a first return stream comprising at least a portion of the bottoms stream to the light ends column;
• (g) directing at least a portion of the raffinate to the light ends column, optionally as part of the first return stream;
• and
• (h) directing a second return stream comprising at least a portion of the bottoms stream to the drying column.

A process for removing permanganate reducing compounds (PRC's) from a crude acetic acid comprising acetic acid and one or more PRC's, the process comprising the steps of:

• (a) separating the crude acetic acid composition in a light ends column into an acetic acid stream and a low-boiling overhead vapor stream comprising the one or more PRC's and;
• (b) separating a portion of the low-boiling overhead vapor stream into an overhead stream an a bottoms stream, wherein the overhead stream is enriched in the one or more PRC's as compared to the bottoms stream;
• and
• (c) directing a first return stream comprising at least a portion of the bottoms stream to the light ends column.