Reducing acetals during ethanol separation process using high pressure distillation column
AssigneeCelanese International Corporation
InventorsDavid Lee, Adam Orosco, Lincoln Sarager, R. Jay Warner, Victor J. Johnston
Life of this patent
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Abstract
To reduce acetal concentrations when separating ethanol from a crude product in one or more distillation column, at least one of the columns is operated at a higher pressure to increase the equilibrium constant that favors hydrolysis of the acetal. The crude product may comprise ethanol, acetaldehyde, water and one or more acetals, such as diethyl acetal. The acetal concentration may be reduced thus reducing the need to separate acetal from the crude product.
Claims20
A method for producing ethanol comprising:
- hydrogenating alkanoic acid and/or esters thereof in a reactor in the presence of a catalyst to form a crude ethanol mixture;
- separating a portion of the crude ethanol mixture in a first distillation column operated above atmospheric pressure to yield a first residue comprising alkanoic acid, and a first distillate comprising ethanol, and acetaldehyde;
- and
- separating a portion of the first distillate in a second distillation column to yield a second residue comprising ethanol, and a second distillate comprising acetaldehyde,
- wherein the second residue comprises less than 1 wt. % diethyl acetal.
A method for producing ethanol comprising:
- providing a crude ethanol mixture comprising acetic acid, acetaldehyde, ethanol, and diethyl acetal;
- separating a portion of the crude ethanol mixture in a first distillation column operated above atmospheric pressure to yield a first residue comprising acetic acid, and a first distillate comprising ethanol, and acetaldehyde;
- and
- separating a portion of the first distillate in a second distillation column to yield a second residue comprising ethanol, and a second distillate comprising acetaldehyde,
- wherein the second residue comprises less than 1 wt. % diethyl acetal.
A method for producing ethanol comprising:
- hydrogenating alkanoic acid and/or esters thereof in a reactor in the presence of a catalyst to form a crude ethanol mixture;
- separating a portion of the crude ethanol mixture in a first distillation column operated above atmospheric pressure to yield a first residue comprising ethanol, and water, and a first distillate comprising ethyl acetate, and acetaldehyde;
- and
- separating a portion of the first residue in a second distillation column to yield a second residue comprising water, and a second distillate comprising ethanol,
- wherein the second distillate comprises less than 1 wt. % diethyl acetal.
A method for producing ethanol comprising:
- providing a crude ethanol mixture comprising acetic acid, acetaldehyde, ethyl acetate, ethanol, and diethyl acetal;
- separating a portion of the crude ethanol mixture in a first distillation column operated above atmospheric pressure to yield a first residue comprising acetic acid, ethanol, and water, and a first distillate comprising ethyl acetate, and acetaldehyde;
- and
- separating a portion of the first residue in a second distillation column to yield a second residue comprising water and acetic acid, and a second distillate comprising ethanol,
- wherein the second distillate comprises less than 1 wt. % diethyl acetal.
Dependencies are inferred from the claim text.