METHODS FOR ENHANCING THE RECOVERY OF OIL DURING BIOFUEL PRODUCTION
Methods for producing biofuels that involve enhanced separation of oil in co-product process streams are disclosed. In some embodiments, separation is enhanced by addition of an additive such as a surfactant, yeast and/or salt to the co-product process stream.
1 . A process for recovering oil from thin stillage obtained in the production of a fuel from a carbon source, the thin stillage being an emulsion comprising water, dissolved solids and oil, the process comprising:
contacting thin stillage with yeast to enhance separation of oil from the thin stillage; and
separating oil from the yeast-containing thin stillage.
2 . The process as set forth in claim 1 wherein the carbon source is a cereal grain selected from the group consisting of corn kernels, wheat berries, oat groats, rye, barley, canola, sorghum, rice and quinoa.
3 . The process as set forth in claim 1 wherein the carbon source is corn kernels.
4 . (canceled)
5 . The process as set forth in claim 1 wherein the thin stillage comprises at least about 5 wt % solids.
6 . The process as set forth in claim 1 wherein the thin stillage is maintained at a temperature of at least about 40° C. after contacting thin stillage with yeast and during oil separation.
7 . The process as set forth in claim 1 wherein at least about 0.05 g of yeast on a dry basis of yeast is added per liter of thin stillage.
8 . (canceled)
9 . The process as set forth in claim 1 wherein the yeast does not consume glycerol in the thin stillage after contacting the thin stillage.
10 . The process as set forth in claim 1 wherein the yeast chemically modifies the emulsion.
11 . (canceled)
12 . The process as set forth in claim 1 wherein oil is separated from the yeast-containing thin stillage by a gravity separation process.
13 . (canceled)
14 . The process as set forth in claim 1 comprising contacting the thin stillage with a surfactant to enhance separation of oil from the thin stillage.
15 . (canceled)
16 . The process as set forth in claim 1 wherein the amount of oil separated from the yeast-containing thin stillage is at least about 1% vol/vol.
17 . A process for recovering oil from thin stillage obtained in the production of a fuel from a carbon source, the thin stillage being an emulsion comprising water, dissolved solids and oil, the process comprising:
contacting thin stillage with a salt suitable to enhance separation of oil from the thin stillage; and
separating oil from the salt-containing thin stillage.
18 . The process as set forth in claim 17 wherein the carbon source is a cereal grain selected from the group consisting of corn kernels, wheat berries, oat groats, rye, barley, canola, sorghum, rice and quinoa.
19 - 22 . (canceled)
23 . The process as set forth in claim 17 wherein at least about 0.005 g of salt is added per liter of thin stillage.
24 - 25 . (canceled)
26 . The process as set forth in claim 17 wherein the salt is a chloride salt.
27 . The process as set forth in claim 17 wherein the salt is chosen from the group consisting of CaCl 2 , KCl, NaCl, and MgCl 2 .
28 - 32 . (canceled)
33 . A process for producing ethanol from a carbon source containing polysaccharides, the process comprising:
reducing the polysaccharides in the carbon source to produce simple sugars;
fermenting the simple sugars to produce ethanol and whole stillage;
separating the whole stillage into a distillers grain component and a thin stillage component; and
recovering oil from the thin stillage component according to the process of claim 1 .
34 - 47 . (canceled)
48 . A process for producing ethanol from a carbon source containing polysaccharides, the process comprising:
reducing the polysaccharides in the carbon source to produce simple sugars;
fermenting the simple sugars to produce ethanol and whole stillage;
separating the whole stillage into a distillers grain component and a thin stillage component;
recovering oil from the thin stillage component according to the process of claim 17 .
49 - 62 . (canceled)
63 . A method for enhancing the separation of oil from a oil-in-water emulsion, the emulsion comprising at least about 1 wt % oil on a dry basis and at least about 5 wt % solids, the process comprising contacting the emulsion with a yeast or with a salt.
64 - 78 . (canceled)
79 . The process as set forth in claim 17 comprising contacting the thin stillage with a surfactant to enhance separation of oil from the thin stillage.