Method for conditioning and processing whole or thin stillage to aid in the separation and recovery of protein and oil fractions
A method of processing thin stillage in an ethanol refining operation is provided. The method comprises treating thin stillage upstream of a concentration or evaporation step with an aid comprising a sorbitan ester of a fatty acid, an ethoxylated sorbitan ester of a fatty acid, or a combination thereof, thereby forming treated thin stillage. The aid may include at least one of sorbitan monooleate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monolaurate.
1. A method of processing thin stillage in an ethanol refining operation, comprising:
treating the thin stillage upstream of a concentration or evaporation step with an aid comprising an anionic flocculant, thereby forming a treated thin stillage;
applying a pressure to the treated thin stillage at a temperature of 220° F.;
centrifuging the treated thin stillage to form an oil layer and an emulsion layer;
separating the oil layer from solids or water of the treated thin stillage; and
recovering the oil;
wherein the aid does not include an emulsifying agent.
2. The method of claim 1 , wherein the centrifuging step is performed via a stacked disk centrifuge.
3. The method of claim 1 , wherein the anionic flocculant is a copolymer of acrylamide and acrylic acid.
4. The method of claim 3 , wherein the copolymer comprises an anionic charge of about 30 to about 70 mole percent.
5. The method of claim 1 , wherein the anionic flocculant is a terpolymer of acrylamide, sodium acrylate, and sodium methacrylate.
6. The method of claim 5 , wherein the terpolymer comprises an anionic charge of about 1 to about 50 mole percent.
7. The method of claim 1 , wherein the anionic flocculant is a copolymer of acrylamide and 2-acrylamido-2-methyl-1-propanesulfonic acid.
8. The method of claim 1 , wherein the anionic flocculant is added to the thin stillage in an amount of about 50 to about 500 ppm.
9. The method of claim 1 , wherein the pressure is 2.5 psi.
10. A method of processing thin stillage in an ethanol refining operation, comprising:
treating the thin stillage upstream of a concentration or evaporation step with an aid comprising an anionic flocculant, thereby forming a treated thin stillage;
applying a pressure to the treated thin stillage at a temperature of 230° F.;
centrifuging the treated thin stillage to form an oil layer and an emulsion layer;
separating the oil layer from solids or water of the treated thin stillage; and
recovering the oil;
wherein the aid does not include an emulsifying agent.
11. The method of claim 10 , wherein the pressure is 6.1 psi.