Process and system for producing ethanol from a byproduct of an ethanol production facility

Abstract

A process of producing ethanol from whole stillage, includes obtaining a supply of whole stillage from an ethanol production facility after ethanol has been extracted therefrom; pre-treating the whole stillage to convert hemicellulose portions of the whole stillage into sugars; adding enzymes to the whole stillage to convert cellulose portions of the whole stillage to sugars; fermenting the whole stillage to create a beer mixture; and distilling the beer mixture to separate ethanol therefrom. The pre-treating step may include adding acid to the whole stillage to decrease its pH level; heating and pressurizing the whole stillage; holding the whole stillage under pressure and heat for a dwell time; removing pressure from the whole stillage to cause flashing; and cooling the whole stillage before the enzymes are added.

Having thus described the preferred embodiment of the invention, what is claimed as new and desired to be protected by Letters Patent includes the following: 
     
         1 . A process of producing ethanol from whole stillage, the method comprising:
 obtaining a supply of whole stillage from an ethanol production facility;   pre-treating the whole stillage to convert hemicellulose portions of the whole stillage into sugars, the pre-treating step comprising:
 adding acid to the whole stillage to decrease its pH level; 
 heating and pressurizing the whole stillage in a hydro-heater where steam is injected to cause cavitation of the whole stillage; 
 holding the whole stillage under pressure and heat for a dwell time; 
 removing pressure from the whole stillage to cause flashing; 
 cooling the whole stillage; 
   adding enzymes to the whole stillage to covert cellulose portions of the whole stillage into sugars;   fermenting the whole stillage to create a beer mixture;   distilling the beer mixture to separate ethanol therefrom;   transferring the ethanol from the distilling step to the ethanol production facility to be combined with ethanol produced by the ethanol production facility.   
     
     
         2 . The process of  claim 1 , wherein the enzymes added include cellulase, cellobiohydrolase, and beta-glucosidase.