Systems and methods for extracting oil from plant material

Abstract

Disclosed are methods and systems for recovering oil from processed plant materials and by-products formed during a milling process used for producing ethanol.

What is claimed is: 
     
         1 . A method of extracting oil from a biorefinery process stream, wherein the method comprises:
 diluting a biorefinery process stream to provide a diluted biorefinery process stream having a total solids content in a range from 15 to less than 35% (wt/wt) based on the total weight of the diluted biorefinery process stream, wherein the biorefinery process stream comprises at least grain oil, grain fiber, and water; and   applying pressure to the diluted biorefinery process stream to separate the diluted biorefinery process stream into at least one liquid fraction and at least one solids fraction and to transfer oil into the at least one liquid fraction.   
     
     
         2 . The method of  claim 1 , wherein applying pressure to the diluted biorefinery process stream comprises passing the diluted biorefinery process stream through a screw press to separate the diluted biorefinery process stream into a liquid fraction and a solids fraction. 
     
     
         3 . The method of  claim 2 , wherein the biorefinery process stream is a first biorefinery process stream, and wherein diluting comprises adding at least a portion of a second biorefinery process stream to the first biorefinery process stream to provide the diluted biorefinery process stream. 
     
     
         4 . The method of  claim 3 , wherein the second biorefinery process stream is chosen from thin stillage, syrup, alcohol, process water, and combinations thereof. 
     
     
         5 . The method of  claim 3 , wherein the second biorefinery process stream comprises thin stillage. 
     
     
         6 . The method of  claim 2 , wherein the total solids content is in a range from 15 to 25% (wt/wt) based on the total weight of the diluted biorefinery process stream. 
     
     
         7 . The method of  claim 2 , wherein the biorefinery process stream is a first solids fraction that is formed by separating an upstream biorefinery process stream into at least the first solids fraction and at least a first liquid fraction, and wherein passing the diluted biorefinery process stream through the screw press separates the diluted biorefinery process stream into a second liquid fraction and a second solids fraction. 
     
     
         8 . The method of  claim 7 , further comprising combining the first liquid fraction, the second liquid fraction, and the second solids fraction to form a combined biorefinery process stream, and passing the combined biorefinery process stream through a centrifuge to separate the combined biorefinery process stream into a third liquid fraction and a third solids fraction. 
     
     
         9 . The method of  claim 8 , further comprising drying the third solids fraction in a dryer. 
     
     
         10 . The method of  claim 7 , further comprising drying the second solids fraction in a dryer, and combining at least a portion of the first liquid fraction with the second liquid fraction to form a combined liquid fraction, and passing the combined liquid fraction through a centrifuge to separate the combined liquid fraction into a third liquid fraction and a third solids fraction. 
     
     
         11 . The method of  claim 2 , wherein the biorefinery process stream is part of a dry-grind process to make ethanol by fermenting sugar derived from corn. 
     
     
         12 . The method of  claim 2 , further comprising recovering or separating oil from the at least one liquid fraction and/or a process stream derived therefrom. 
     
     
         13 . The method of  claim 2 , further comprising heating the biorefinery process stream and/or heating the diluted biorefinery process stream. 
     
     
         14 . The method of  claim 2 , further comprising treating the biorefinery process stream with one or more enzymes and/or treating the diluted biorefinery process stream with one or more enzymes, wherein the one or more enzymes are chosen from one or more amylase enzymes, one or more cellulase enzymes, one or more hemicellulase enzymes, one or more protease enzymes, and combinations thereof. 
     
     
         15 . The method of  claim 14 , further comprising milling the biorefinery process stream after treating the biorefinery process stream with one or more enzymes and/or milling the diluted biorefinery process stream after treating the diluted biorefinery process stream with one or more enzymes. 
     
     
         16 . The method of  claim 2 , further comprising milling the biorefinery process stream and/or milling the diluted biorefinery process stream. 
     
     
         17 . A method of extracting oil from a wet cake, wherein the method comprises:
 providing a wet cake comprising a total solids content in a range from 15 to less than 35% (wt/wt) based on the total weight of the wet cake; and   applying pressure to the wet cake to separate the wet cake into a liquid fraction and a solids fraction.   
     
     
         18 . The method of  claim 17 , further comprising recovering or separating oil from the liquid fraction and/or a process stream derived therefrom. 
     
     
         19 . The method of  claim 17 , wherein providing the wet cake comprises separating wet cake from whole stillage so that the wet cake comprises a total solids content in a range from 15 to less than 35% (wt/wt) based on the total weight of the wet cake. 
     
     
         20 . The method of  claim 19 , wherein separating wet cake from whole stillage comprises screening, filtering and/or centrifuging the whole stillage. 
     
     
         21 . The method of  claim 19 , wherein separating wet cake from whole stillage comprises passing whole stillage through one or more gravity screens, one or more decanting centrifuges, one or more disk stack centrifuges, one or more hydroclones, one or more settling tanks, and combinations thereof. 
     
     
         22 . The method of  claim 20 , wherein providing the wet cake comprises separating wet cake from whole stillage and diluting wet cake with a diluent so that the wet cake comprises a total solids content in a range from 15 to less than 35% (wt/wt) based on the total weight of the wet cake. 
     
     
         23 . A method of extracting oil from a biorefinery process stream, wherein the method comprises:
 evaporating moisture from a biorefinery process stream to provide a condensed biorefinery process stream having a total solids content in a range from 15 to less than 35% (wt/wt) based on the total weight of the condensed biorefinery process stream, wherein the biorefinery process stream comprises at least grain oil, grain fiber, and water; and   mechanically pressing the condensed biorefinery process stream against a screen to separate the condensed biorefinery process stream into at least one liquid fraction and at least one solids fraction and to transfer oil into the at least one liquid fraction.   
     
     
         24 . A method of extracting oil from a biorefinery process stream, wherein the method comprises:
 providing a biorefinery process stream comprising a total solids content in a range from 15 to less than 35% (wt/wt) based on the total weight of the biorefinery process stream, wherein the biorefinery process stream comprises at least grain oil, grain protein, grain fiber, and an aqueous carrier;   physically disrupting the biorefinery process stream, wherein physically disrupting comprises a process chosen from pressing, milling, and combinations thereof; and   separating the biorefinery process stream into at least one liquid fraction comprising grain oil, and at least one solids fraction.