Process for Producing Ethanol Using Acetic Acid from a Carbonylation Process

A process for producing ethanol, comprising the steps of:

• (a) reacting carbon monoxide with at least one reactant in a first reactor containing a reaction medium to produce a liquid reaction product comprising acetic acid, wherein the reaction medium comprises water, acetic acid, methyl acetate, a halogen promoter, and a first catalyst;
• (b) separating the reaction product in a flasher into a liquid recycle stream and a vapor stream comprising acetic acid, the halogen promoter, methyl acetate, water, and mixtures thereof;
• (c) separating the vapor stream in a first column to yield a first overhead stream comprising methyl acetate, acetaldehyde, the halogen promoter, water, and mixtures thereof, an acetic acid product sidedraw, and an optional first residue stream;
• (d) separating the acetic acid product sidedraw in a second column to yield a second overhead stream comprising water, methyl acetate, the halogen promoter, and mixtures thereof and a second residue comprising acetic acid;
• (e) hydrogenating acetic acid from a portion of the second residue in a second reactor in the presence of a catalyst under conditions effective to form a crude ethanol product;
• (f) separating at least a portion of the crude ethanol product in a third column to yield a third overhead comprising ethanol, water, and ethyl acetate, and a third residue comprising acetic acid and less than 30 wt. % water;
• (g) directing at least a portion of the third residue to the first column and/or second column;
• and
• (h) recovering ethanol from the third overhead.

A process for producing ethanol, comprising the steps of:

• (a) reacting carbon monoxide with at least one reactant in a first reactor containing a reaction medium to produce a liquid reaction product comprising acetic acid, wherein the reaction medium comprises water, acetic acid, methyl acetate, a halogen promoter, and a first catalyst;
• (b) separating the reaction product in a flasher into a liquid recycle stream and a vapor stream comprising acetic acid, the halogen promoter, methyl acetate, water, and mixtures thereof;
• (c) separating the vapor stream in a first column to yield a first overhead stream comprising methyl acetate, acetaldehyde, the halogen promoter, water and mixtures thereof, an acetic acid product sidedraw, and an optional first residue stream;
• (d) separating the acetic acid product sidedraw in a second column to yield a second overhead stream comprising water, methyl acetate, the halogen promoter, and mixtures thereof and a second residue comprising acetic acid;
• (e) hydrogenating acetic acid from a portion of the second residue in a second reactor in the presence of a catalyst under conditions effective to form a crude ethanol product;
• (f) separating at least a portion of the crude ethanol product in a third column to yield a third residue comprising acetic acid and a substantial portion of the water and a third overhead comprising ethanol, ethyl acetate, and water;
• (g) removing water from at least a portion of the third overhead to yield an ethanol mixture stream comprising less than 10 wt. % water;
• and
• (h) separating a portion of the ethanol mixture stream in a fourth column to yield a fourth residue comprising ethanol and a fourth overhead comprising ethyl acetate;
• and
• (i) directing at least a portion of the third residue to the first column and/or the second column.

A process for producing ethanol, comprising the steps of:

• (a) reacting carbon monoxide with at least one reactant in a first reactor containing a reaction medium to produce a liquid reaction product comprising acetic acid, wherein the reaction medium comprises water, acetic acid, methyl acetate, a halogen promoter, and a first catalyst;
• (b) separating the reaction product in a flasher into a liquid recycle stream and a vapor stream comprising acetic acid, the halogen promoter, methyl acetate, water, and mixtures thereof;
• (c) separating the vapor stream in a first column to yield a first overhead stream comprising methyl acetate, acetaldehyde, the halogen promoter, water, and mixtures thereof, an acetic acid product sidedraw, and an optional first residue stream;
• (d) separating the acetic acid product sidedraw in a second column to yield a second overhead stream comprising water, methyl acetate, the halogen promoter, and mixtures thereof and a second residue comprising acetic acid;
• (e) hydrogenating acetic acid from a portion of the second residue in a second reactor the presence of a catalyst under conditions effective to form a crude ethanol product;
• (f) separating a portion of the crude ethanol product in a third column to yield a third overhead comprising ethyl acetate and acetaldehyde, and a third residue comprising ethanol, ethyl acetate, acetic acid and water;
• (g) separating a portion of the first residue in a fourth column to yield a fourth residue comprising acetic acid and water and a fourth overhead comprising ethanol and ethyl acetate;
• and
• (i) directing at least a portion of the fourth residue to the first and/or second column.