Recovery of desired co-products from fermentation stillage streams
Processes and methods of recovering desired products from fermentation stillage are presented, including processes and methods of recovering lipids and aqueous materials.
1. A method of recovering oil from stillage, the method comprising, in sequence:
generating stillage;
mechanically separating a mixture comprising a light phase oil material stream having an emulsion from the stillage, wherein the light phase oil material stream has a moisture content of greater than about 5% by weight;
chemically processing the separated light phase oil material to generate a pH adjusted mixture with a pH of greater than about 6 and less than about 11; and
recovering oil from the pH adjusted mixture.
2. The method of claim 1 , wherein the stillage is thin stillage.
3. The method of claim 1 , wherein the stillage is syrup.
4. The method of claim 1 , wherein mechanically separating the light phase oil material comprises centrifugation.
5. The method of claim 1 , wherein mechanically separating the light phase oil material comprises filtration.
6. The method of claim 4 , wherein the centrifugation comprises use of a disk type centrifuge.
7. The method of claim 4 , wherein separating the light phase oil material from the stillage further comprises generating an aqueous phase mixture and a solids phase mixture in addition to the light phase oil material.
8. The method of claim 1 , further comprising chemically pretreating the stillage to change a physical binding characteristic, solubility, or specific gravity of compounds in the stillage.
9. The method of claim 8 , wherein chemically pretreating the stillage liberates oil from oil-solid-water suspensions in the stillage.
10. The method of claim 8 , wherein the stillage is syrup.
11. The method of claim 1 , wherein the stillage is heated prior to mechanically separating the light phase oil material.
12. The method of claim 1 , wherein the light oil phase material stream is evaporated prior to recovering oil.
13. The method of claim 1 , wherein the stillage is generated from pretreated biomass particles having a relatively uniform particle size, wherein at least 95% of the biomass particles have a particle size from about 100 microns to about 800 microns.
14. The method of claim 1 , wherein the stillage is generated from pretreated biomass particles processed by a colloidal mill.
15. The method of claim 1 , wherein chemical processing of the light phase oil material comprises the addition of alkali metal or basic, ionic salt.
16. The method of claim 15 , wherein the alkali metal or basic, ionic salt comprises hydroxide or carbonate ion in a solution.
17. The method of claim 15 , wherein the basic, ionic salt comprises a solution of sodium hydroxide wherein the concentration of the sodium hydroxide solution is between about 1% and about 99% sodium hydroxide by weight.
18. The method of claim 1 , wherein the pH adjusted mixture has a pH of 6-7.5.
19. The method of claim 1 , wherein the light phase oil material stream has an oil content of at least 50% by weight.
20. The method of claim 1 , wherein the light phase oil material stream has a specific gravity as measured at room temperature of 0.90 to 0.98.