A system for producing ethanol comprises a rectifier column that receives a first process stream comprising from about 42% to about 60% ethanol, wherein the rectifier column purifies the first process stream to provide an ethanol product stream that is at least about 90% ethanol, and one or more evaporators configured to evaporate water from a second process stream, wherein the one or more evaporators generate vapor, and wherein at least a portion of the vapor supplies heat energy for separation of ethanol from water in the rectifier column.

A system for producing ethanol comprises a rectifier column that receives a first process stream comprising from about 42% to about 60% ethanol, wherein the rectifier column purifies the first process stream to provide an ethanol product stream that is at least about 90% ethanol, and one or more evaporators configured to evaporate water from a second process stream, wherein the one or more evaporators generate vapor, and wherein at least a portion of the vapor supplies heat energy for separation of ethanol from water in the rectifier column.

A system and method for expanding the production capacity of an existing ethanol production facility including: a source of fermented mash (beer); a first beer column configured for receiving beer input from the source and for producing overhead comprising alcohol vapor and water vapor; and a first rectifier receiving an alcohol and water mixture from said first beer column. The system includes a second beer column, first and second condensers receiving overhead from the beer columns and a second rectifier receiving condensed overhead from the second condenser and bottoms from the first rectifier. A processing component receives bottoms from the first and second beer columns and steam condensate. The method includes the steps of retrofitting an existing ethanol production facility with a second beer column, first and second condensers and a second rectifier.