Solvent extraction of oil from distillers dried grains and methods of using extraction products
A process for extraction of crude oil from distillers dried grain solubles and/or distillers dried grains using a solvent extraction process and producing corn distillers meal that may be used as an animal feed supplement is disclosed. The corn distillers meal may be used as a crude protein supplement for use in a livestock feed diet, poultry feed diet, aquatic feed diet or the like. The solvent extracted crude oil may be suitable for other processes, including oleochemical processing for personal care and home care products, biodiesel production, and/or renewable diesel production from hydro-treating the extracted oil to make green diesel fuel.
1. A method of producing renewable fuel from crude corn oil produced from at least one by-product of a dry-grind ethanol process, the method comprising:
solvent extracting crude corn oil from a by-product produced in a dry-grind ethanol process with a non-polar solvent, the at least one by-product comprising distillers dried grains with solubles, distillers dried grains, or a combination thereof, wherein the crude corn oil comprising free fatty acids in an amount ranging from about 1% to about 15% by weight of the crude corn oil, and the crude corn oil having a residual level of the non-polar solvent in an amount from about 1 ppm to about 500 ppm;
pretreating the crude corn oil prior to a conversion process, wherein the pretreatment comprises degumming the crude corn oil to separate and remove a gum portion from a crude corn oil portion;
drying the crude corn oil portion under vacuum to a desired water content; and
subjecting the dried crude corn oil portion to a conversion process to produce the renewable fuel.
2. The method of claim 1 , further comprising washing the crude corn oil portion with water to remove one or more impurities from the crude corn oil portion prior to the drying process.
3. The method of claim 1 , further comprising filtering the dried crude corn oil portion with one or more adsorptive filtration medias comprising an acid activated clay, a non-acid activated clay, or a silica based product, in an amount between 0.1% and 5% to remove one or more impurities.
4. The method of claim 1 , wherein the pretreatment step further comprises hydrating the crude corn oil with at least one hydrating agent to provide the gum portion and the crude corn oil portion prior to the degumming process.
5. The method of claim 4 , wherein the at least one hydrating agent comprises one or more acids, water, or a combination thereof.
6. The method of claim 5 , wherein the hydrating agent comprises one or more acids or a combination of one or more acids and water, and the pretreatment step further comprises neutralizing the one or more acids with a base after the hydrating process and prior to the removal of the gum portion.
7. The method of claim 4 , wherein the degumming process further comprises centrifuging the hydrated crude corn oil to separate and remove the gum portion from the crude corn oil portion.
8. The method of claim 4 , wherein the conversion process comprises hydrotreating the crude corn oil portion in the presence of hydrogen and a catalyst to produce the renewable fuel, wherein the renewable fuel is renewable green diesel.
9. The method of claim 4 , wherein the conversion process comprises hydrotreating the crude corn oil in the presence of hydrogen and a catalyst to produce a deoxygenated fuel product, hydroisomerization of the deoxygenated fuel product in the presence of a hydrocracking catalyst to produce an isomerized fuel product, and fractional distilling the isomerized fuel product to produce the renewable fuel.
10. The method of claim 9 , wherein the renewable fuel comprises one or more renewable green product selected from renewable green propane, renewable green naphtha, renewable green diesel and renewable green jet fuel.
11. The method of claim 1 , wherein the renewable fuel is produced onsite at an ethanol facility.
12. The method of claim 1 , wherein the renewable fuel comprises renewable green diesel.
13. The method of claim 1 , wherein the crude corn oil comprises phosphorous in an amount no more than about 0.05%.
14. The method of claim 1 , wherein the crude corn oil comprises phosphorous in an amount no more than about 0.04%.
15. The method of claim 1 , wherein the non-polar solvent has a boiling point in the range of about 36° C. to about 99° C.
16. The method of claim 15 , wherein the non-polar solvent comprises one or more C 5 -C 7 -isomers chosen from n-pentane, n-hexane, n-heptane, isopentane, neopentane, isohexane, 2-methylpentane, 2,3-dimethylbutane, neohexane, isoheptane, 2-methylhexane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3-ethylpentane, and 2,2,3-trimethylbutane, petroleum ether, or mixtures thereof.
17. The method of claim 1 , wherein the non-polar solvent comprises n-hexane, isohexane, structural isomers thereof, or mixtures thereof.
18. The method of claim 17 , wherein the residual level of the non-polar solvent is in an amount from about 1 ppm to about 100 ppm.
19. The method of claim 1 , wherein the non-polar solvent comprises n-hexane or structural isomers of n-hexane.
20. The method of claim 1 , wherein the non-polar solvent comprises n-hexane or structural isomers of n-hexane, and wherein the residual level of the non-polar solvent is in an amount from about 1 ppm to about 100 ppm.