Bio-oil recovery methods

1. A method comprising:

dewatering a bio-oil process stream from a biomass processing facility with a mechanical processor to produce a de-oiled process stream and an emulsion concentrate, wherein the emulsion concentrate contains entrapped bio-oil;

combining an emulsion-breaking additive with the emulsion concentrate in an amount sufficient to release the entrapped bio-oil from the emulsion concentrate and produce a reaction product containing released bio-oil and an amount of the emulsion-breaking additive, wherein the emulsion-breaking additive is a polar protic solvent;

removing at least some of the emulsion breaking additive from the reaction product to yield a broken emulsion concentrate; and

phase separating the broken emulsion concentrate to yield an aqueous phase and a bio-oil phase.

2. The method of claim 1 wherein the process stream is a concentrated stillage having a moisture content of about 5% by weight, up to less than 30% by weight and the de-oiled process stream is de-oiled concentrated stillage.

3. The method of claim 2 wherein the combining step is performed at a temperature of about 22° C. to about 121° C.

4. The method of claim 1 wherein the mechanical processor is a centrifuge.

5. The method of claim 4 wherein the emulsion breaking additive is removed with flash evaporation.

6. The method of claim 5 wherein the phase separating is accomplished with gravity separation or with mechanical processing.

7. The method of claim 1 wherein the process stream further contains bio-oil bound to components in the process stream, bio-oil trapped by components in the process stream, or both, wherein the bound or trapped bio-oil is also released.

8. The method of claim 7 wherein the bio-oil is a vegetable oil or animal fat.

9. The method of claim 1 wherein the emulsion breaking additive is heated prior to being combined with the process stream.

10. The method of claim 1 wherein the polar protic solvent is ethanol or glycerol.

11. The method of claim 1 further comprising recovering the released bio-oil in the bio-oil phase.

12. A method comprising:

dewatering a bio-oil process stream from a biomass processing facility with a mechanical processor to produce a de-oiled process stream and an emulsion concentrate, wherein the emulsion concentrate contains entrapped bio-oil;

combining an emulsion-breaking additive with the emulsion concentrate in an amount sufficient to release the entrapped bio-oil from the emulsion concentrate and produce a reaction product containing released bio-oil and an amount of the emulsion-breaking additive, wherein the emulsion-breaking additive is a polar protic solvent;

phase separating the reaction product to yield a broken emulsion concentrate;

mechanically processing the broken emulsion concentrate to yield an aqueous phase and a bio-oil phase, wherein the bio-oil phase contains the emulsion-breaking additive; and

removing at least some of the emulsion breaking additive from the bio-oil phase.

13. The method of claim 12 further comprising recovering the released bio-oil in the bio-oil phase.

14. A method comprising:

dewatering a bio-oil process stream from a biomass processing facility with a mechanical processor to produce a de-oiled process stream and a stable emulsion, wherein the stable emulsion contains entrapped bio-oil;

combining an emulsion-breaking additive with the stable emulsion, wherein the emulsion-breaking additive is a polar protic solvent added in an amount effective to at least partially break the stable emulsion to release the entrapped bio-oil from the stable emulsion and produce a reaction product containing released bio-oil and an amount of the emulsion-breaking additive;

removing at least some of the emulsion breaking additive from the reaction product to yield a broken emulsion;

phase separating the broken emulsion to yield an aqueous phase and a bio-oil phase containing the released bio-oil; and

recovering the released bio-oil from the bio-oil phase.

15. The method of claim 14 wherein the emulsion breaking additive is removed with flash evaporation and the phase separating is accomplished with gravity separation or mechanical processing.

16. A method comprising:

dewatering a bio-oil process stream from a biomass processing facility with a mechanical processor to produce a de-oiled process stream and a stable emulsion, wherein the stable emulsion contains entrapped bio-oil;

combining an emulsion-breaking additive with the stable emulsion, wherein the emulsion-breaking additive is a polar protic solvent added in an amount effective to at least partially break the stable emulsion to release the entrapped bio-oil from the stable emulsion and produce a reaction product containing released bio-oil and an amount of the emulsion-breaking additive;

phase separating the reaction product to produce a broken emulsion;

mechanically processing the broken emulsion to yield an aqueous phase and a bio-oil phase, wherein the bio-oil phase contains the emulsion-breaking additive;

removing at least some of the emulsion breaking additive from the bio-oil phase; and recovering the released bio-oil from the bio-oil phase.

17. A method comprising:

dewatering a concentrated thin stillage stream from an ethanol production facility with a mechanical processor to produce de-oiled concentrated thin stillage and an emulsion concentrate, wherein the emulsion concentrate contains entrapped bio-oil;

combining ethanol with the emulsion concentrate in an amount sufficient to destabilize the emulsion concentrate and produce a reaction product containing released bio-oil and an amount of the ethanol;

removing at least some of the ethanol from the reaction product to yield a broken emulsion concentrate;

phase separating the broken emulsion concentrate to yield an aqueous phase and a bio-oil phase; and recovering the released bio-oil in the bio-oil phase, wherein the released bio-oil phase comprises corn oil.