Abstract: A process for producing ethanol is disclosed, comprising the steps of hydrogenating acetic acid in a reactor in the presence of a catalyst to form a crude ethanol product, separating at least a portion of the crude ethanol product in a column into a first distillate comprising ethanol and a first residue comprising acetic acid and water, wherein a substantial portion of the water in the crude ethanol product that is fed to the column is removed in the first residue, and separating a portion of the ethanol mixture stream to the second distillation column to yield an ethanol product sidedraw, second residue comprising water and a second distillate comprising ethyl acetate. The water content of the ethanol product sidedraw may be further reduced to yield a stream having reduced water content.

Abstract: To reduce acetal and/or ester 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, ethyl acetate and one or more acetals, such as diethyl acetal. The acetal and/or ester concentration may be reduced thus reducing the need to separate acetal and/or ester from the crude product.

Abstract: Recovery of alcohols, in particular ethanol, from a crude ethanol product obtained from the hydrogenation of acetic acid using pressure driven distillation to separate the crude ethanol product. The crude ethanol product may be fed to a distillations column in which a substantial portion of the water is removed with the acetic acid in the residue. A second column is at higher pressure than a first column.

Abstract: Recovery of ethanol from a crude ethanol product obtained from the hydrogenation of acetic acid. The crude ethanol product is fed to a distillation column to yield an ethanol sidestream.

Abstract: A process for operating a distillation column to separate an ethanol mixture comprising ethanol and acetic acid where the recovered ethanol comprises less than 700 wppm acetic acid. The operating conditions for the column may vary depending on the fed composition. In particular the process provides energy efficient recovery of ethanol with low concentration acetic acid.

Abstract: This invention relates to processes for producing ethanol from at least two different streams obtained by carbonylating methanol. The process comprises the steps of reacting carbon monoxide with at least one reactant in a first reactor containing a reaction medium to produce a reaction solution comprising acetic acid, wherein the at least one reactant is selected from the group consisting of methanol, methyl acetate, methyl formate, dimethyl ether and mixtures thereof and wherein the reaction medium comprises water, acetic acid, methyl iodide, and a first catalyst, purifying the reaction solution to yield an acetic acid product stream and at least one derivative stream, introducing the acetic acid product stream and the at least one derivative stream into a second reactor in the presence of a second catalyst to form a crude ethanol product, and recovering ethanol from the crude ethanol product.

Abstract: In one embodiment, the invention is to a process for producing ethanol, the process comprising the steps of carbonylating methanol in a carbonylation system in the presence of a carbonylation catalyst under conditions effective to form acetic acid; hydrogenating the acetic acid in a hydrogenation system in the presence of a hydrogenation catalyst to form a crude ethanol product comprising ethanol and water; separating the ethanol from the water to form an ethanol stream and a water stream; and directing at least a portion of the water stream to the carbonylation system, e.g., for use as an extractant in a permanganate reducing compound removal system.

Abstract: A process for recovering ethanol obtained from the hydrogenation of acetic acid. The crude ethanol product is separated in a column to produce a distillate stream comprising acetaldehyde and ethyl acetate and a residue stream comprising ethanol, acetic acid, ethyl acetate and water. Unreacted acetic acid can be reduced or removed through configurations of esterification secondary reactors. The ethanol product is recovered from the residue stream.

Abstract: In one embodiment, the invention is to a process for purifying a crude ethanol product. The process comprises the step of hydrogenating acetic acid in a first reaction zone in the presence of a first catalyst to form the crude ethanol product comprising ethanol, acetaldehyde, acetic acid, water, and acetal. The process further comprises the step of separating at least a portion of the crude ethanol product into a refined ethanol stream and a by-product stream. The refined ethanol stream comprises ethanol and acetaldehyde; and the by-product stream comprises acetic acid and a substantial portion of the water from the crude ethanol product. The process further comprises the step of hydrolyzing in a second reaction zone at least a portion of the acetal.

Abstract: A process for operating a distillation column to separate an ethanol mixture comprising ethanol and acetic acid where the recovered ethanol comprises less than 700 wppm acetic acid. The operating conditions for the column may vary depending on the fed composition. In particular the process provides energy efficient recovery of ethanol with low concentration acetic acid.

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.

Abstract: Recovery of an alcohol such as ethanol from a crude alcohol product, preferably obtained from the hydrogenation of acetic acid using a low energy process. The crude ethanol product is separated in a column to produce a distillate stream comprising ethyl acetate and a residue stream comprising ethanol, acetic acid, and water. The ethanol product is recovered in a second column as an ethanol side stream.

Abstract: To reduce acetal and/or ester 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, ethyl acetate and one or more acetals, such as diethyl acetal. The acetal and/or ester concentration may be reduced thus reducing the need to separate acetal and/or ester from the crude product.

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.

Abstract: To reduce acetal concentrations when separating ethanol from a crude product in one or more distillation column, at least one of the columns has a stripping section that comprises at least 40 stages to favor 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.

Abstract: A process for reducing ethyl acetate and/or diethyl acetal concentration of a crude ethanol product by hydrolysis is disclosed. A portion of the water is initially separated from the crude ethanol product in a first column residue. Ethyl acetate in the first column distillate is hydrolyzed to form additional ethanol and acetic acid. Product ethanol is recovered in a second distillation column preferably in a side stream and acetic acid is removed in the second column residue.

Abstract: Recovery of alcohol, in particular ethanol, from a crude product obtained from the hydrogenation of acetic acid using various combinations of membranes and/or distillation columns.

Abstract: A process for removing water from an acetic acid stream in the production of alcohols, such as ethanol produced by hydrogenating acetic acid. Water is removed from the acetic acid stream using an adsorption unit, membrane, molecular sieves, or a combination thereof, to form a return stream. The return stream may be recycled to the hydrogenation reactor.

Abstract: A process for recovering ethanol obtained from the hydrogenation of acetic acid. The crude ethanol product is separated in a column to produce a distillate stream comprising acetaldehyde and ethyl acetate and a residue stream comprising ethanol, acetic acid and water. Acetal byproduct can be reduced or removed through configurations of hydrolysis secondary reactors. The ethanol product is recovered from the residue stream.

Abstract: Recovery of ethanol from a crude ethanol product obtained from the hydrogenation of acetic acid using a low energy process. The crude ethanol product is separated in a column to produce a distillate stream comprising ethyl acetate and a residue stream comprising ethanol, acetic acid, and water. The ethanol product is recovered from the residue stream.