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:
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 concentrated thin stillage.
3. The method of claim 1 , wherein mechanically separating the light phase oil material comprises centrifugation.
4. The method of claim 3 , wherein the centrifugation comprises use of a disk type centrifuge.
5. The method of claim 3 , 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.
6. The method of claim 1 , wherein chemical processing of the light phase oil material comprises the addition of alkali metal or basic, ionic salt.
7. The method of claim 6 , wherein the alkali metal or basic, ionic salt comprises hydroxide or carbonate ion in a solution.
8. The method of claim 6 , 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.
9. The method of claim 7 , wherein the solution is between about 5% and about 50% concentration by weight.
10. The method of claim 7 , wherein the solution comprises a clean in place (CIP) solution or a waste CIP solutions.
11. The method of claim 1 , wherein the mechanical separating step is performed on the stillage at a temperature of between about 140° F. and about 212° F.
12. The method of claim 1 , wherein the chemical processing is performed on the light phase oil material at a temperature of between about 100° F. and about 212° F.
13. The method of claim 1 , wherein the pH adjusted mixture has a pH of 6-7.5.
14. 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.