Removing hydrocarbon impurities from acetic acid production intermediate
AssigneeLyondell Chemical Technology, L.P.
InventorsNoel Hallinan, Brian A. Salisbury, Shao-Hua Guo
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Abstract
A method for removing hydrocarbon impurities from an acetic acid production intermediate is disclosed. The method comprises extracting the intermediate with a hydrocarbon extracting agent. The extraction is preferably performed with the alkane distillation bottom stream which comprises methyl iodide, acetic acid, and hydrocarbon impurities. The extraction forms a light phase which comprises the hydrocarbon impurity and the extracting agent and a heavy phase which comprises methyl iodide and acetic acid. The extraction heavy phase is optionally recycled to the alkane distillation or to the carbonylation reaction.
Claims14
A method for removing a hydrocarbon impurity from an acetic acid production intermediate, said method comprising extracting the intermediate with a hydrocarbon extracting agent to form a light phase comprising the hydrocarbon impurity and the extracting agent and a heavy phase comprising acetic acid.
A method for producing acetic acid comprising:
- (a) reacting methanol and carbon monoxide in the presence of a carbonylation catalyst, a catalyst stabilizer, methyl iodide, water and methyl acetate to produce an acetic acid stream comprising a hydrocarbon impurity;
- (b) flashing the acetic acid stream into a vapor stream comprising acetic acid, water, methanol, methyl acetate, methyl iodide and the hydrocarbon impurity, and a liquid stream comprising the catalyst and the catalyst stabilizer;
- (c) separating the vapor stream from step (b) by distillation into a product stream comprising acetic acid and water, and an overhead stream comprising methyl iodide, water, methyl acetate, acetic acid, and the hydrocarbon impurity;
- (d) condensing the overhead stream from step (c) into a light, aqueous phase comprising water, and acetic acid, methyl acetate, and a heavy, organic phase comprising methyl iodide, acetic acid, water, and the hydrocarbon impurity;
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- (e) distilling the heavy, organic phase from step (d) into a vapor stream comprising methyl iodide and a bottoms stream comprising acetic acid, methyl iodide, water, and the hydrocarbon impurity;
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- (f) extracting the bottoms stream from step (e) with a hydrocarbon extracting agent, and forming a light phase comprising the hydrocarbon impurity and the extracting agent and a heavy phase comprising methyl iodide, water, and acetic acid.
Dependencies are inferred from the claim text.