Method of freeing the bound oil present in whole stillage and thin stillage
View Patent ↗A method is provided for recovering oil from stillage including oil resulting from a process used for producing ethanol. In one embodiment, the method includes heating the stillage to a temperature sufficient to at least partially separate, or unbind, the oil therefrom The method further includes recovering the oil from the stillage.
1. A method of recovering oil from stillage, including oil, resulting from a process used for producing ethanol, comprising:
recovering whole stillage from the process used for producing the ethanol;
mechanically processing the whole stillage to provide distillers wet grains and thin stillage;
evaporating the thin stillage to form a thin stillage concentrate;
heating the thin stillage concentrate to a temperature greater than 212° F. and a pressure sufficient to prevent boiling; and
recovering the oil from the thin stillage concentrate.
2. The method of claim 1 , wherein the temperature is at about 230° F. to less than about 250° F.
3. The method of claim 1 , wherein the heating the thin stillage concentrate includes maintaining a pressure on the thin stillage concentrate of at least a vapor pressure effective to unbind at least part of the oil without boiling the thin stillage concentrate.
4. The method of claim 1 , further comprising lowering the pressure after the heating but before the recovering the oil.
5. The method of claim 1 , wherein the recovering the oil comprises separating the oil from the thin stillage concentrate using a gravity separation process.
6. The method of claim 1 , further comprising cooling the thin stillage concentrate after heating and before recovering the oil.
7. A method of recovering oil from concentrated stillage including oil resulting from a process used for producing ethanol, comprising:
pressure cooking the concentrated stillage at a temperature greater than 212° F. without boiling to unbind the oil from the stillage; and recovering the unbound oil.
8. A method of recovering oil from thin stillage including oil resulting from a process used for producing ethanol, comprising:
evaporating the thin stillage to form a thin stillage concentrate;
hydrolyzing solids in the thin stillage concentrate so as to reduce a viscosity of the concentrate; and
recovering the oil from the thin stillage concentrate.
9. The method of claim 8 , wherein hydrolyzing solids in the thin stillage concentrate comprises heating the stillage to a temperature greater than 212° F. at a pressure greater than atmospheric pressure without boiling.
10. The method of claim 8 , further comprising cooling the thin stillage concentrate before recovering the oil.
11. The process of claim 1 , wherein the recovering the oil comprises centrifuging the oil from the thin stillage concentrate.