Dry-mill ethanol plant extraction enhancement

1. A method of producing an oil that has not been thermally degraded from a converted mash in a dry mill ethanol production facility, said method comprising:

(a) milling feedstock grains to produce flour;

(b) adding water to the flour to form a mash;

(c) adding enzymes to the mash to form a converted mash;

(d) rinsing the converted mash with a dilute solvent stream consisting essentially of from 2% to 10% ethanol and from 90% to 98% water to separate a water and sugar component from a solid residue;

(e) rinsing only the solid residue with 100% ethanol at a temperature of from about 90 degrees F. to about 110 degrees F. to extract a miscella and a fibrous solids component; and

(f) precipitating protein from the miscella by passing the miscella through an evaporator/separator while heating said miscella at a temperature and pressure selected from 120 degrees F. to 150 degrees F. at atmospheric pressure or 120 degrees F. to 130 degrees F. at about 18 inches of vacuum,

wherein an oil that is not thermally degraded is produced from steps (a) through (f).

2. The method of claim 1 , wherein the feedstock grains comprise whole kernel corn or flaked corn.

3. The method of claim 1 , wherein the dilute solvent stream consists essentially of 2% ethanol and 98% water.

4. The method of claim 1 , wherein the temperature of the dilute solvent stream is about 100° F.

5. The method of claim 1 , wherein the step of rinsing the converted mash further comprises:

feeding the converted mash onto a porous grating of a mechanical extractor apparatus; and

raking the converted mash over the grating;

wherein the rinsing comprises spraying the converted mash with said dilute solvent stream using a solvent spraying system.

6. The method of claim 5 , wherein the temperature of the converted mash fed onto the porous grating is between about 175° F. and 185° F.

7. The method of claim 5 , wherein the temperature of the dilute solvent stream is about 100° F.

8. The method of claim 5 , wherein the temperature of the converted mash fed onto the porous grating is between about 90° F. and 110° F.

9. A method for extracting oil that has not been thermally degraded from a converted mash, said method comprising:

first rinsing a feedstock grain mash with a dilute solvent stream consisting essentially of from 2 to 10% ethanol and from 90 to 98% water to separate water and sugars from feedstock grain solids;

after the grain solids are separated from the water and sugars, rinsing only the solids with a concentrated solvent stream of 100% ethanol at a temperature of from about 90 degrees F. to about 110 degrees F. to separate extractable solute from the solids;

heating the extractable solute to a predetermined temperature and pressure selected from a temperature of about 135 degrees F. at atmospheric pressure or a temperature of about 125 degrees F. at about 18 inches of vacuum to separate oils from the extractable solute; and

producing an oil from the extractable solute that has not been thermally degraded.

10. A method for producing an oil that has not been thermally degraded from a converted mash in a dry mill ethanol production facility without affecting the sugars in the fluid streams, said method comprising:

milling feedstock grains to produce flour;

adding water to the flour to form a mash;

adding enzymes to the mash to convert starches in the feedstock grains to sugars to form a converted mash comprising the water, the sugars, and feedstock grain solids;

rinsing the converted mash with a mixture consisting essentially of from 2 to 10% ethanol and from 90 to 98% water to separate the water and the sugars from feedstock grain solids to form a solid residue;

extracting miscella from the solid residue by rinsing the solid residue with a concentrated solvent stream of 100% ethanol at a temperature of from about 90 degrees F. to about 110 degrees F.;

separating oils and proteins from the miscella by heating the miscella to a predetermined temperature and pressure selected from a temperature of about 135 degrees F. at atmospheric pressure or a temperature of about 125 degrees F. at about 18 inches of vacuum; and

producing an oil that has not been thermally degraded from the miscella.