Light phase product recovery methods and systems
View Patent ↗Methods and systems for recovering a desired co-product from a feedstock to ethanol production process are provided. The methods involve a multi-step separation of a fermentation-derived feedstock, in which an initial separation produces a discharge stream and an output feed stream including the co-product, and a final separation further purifies the output feed stream while also producing a recycle stream that is reintroduced into the separation process. The systems include at least an initial and at least a final separation device which are in fluid communication in both upstream and downstream directions. The initial separation device separates at least a portion of a non-co-product containing phase from a feed stream comprising the non-co-product containing phase and a co-product containing phase, and the final separation device separates at least a portion of the co-product containing phase from a stream comprising the co-product containing phase and a non-co-product containing phase.
1. A method of recovering oil from an oil-containing, grain-based feedstock-to-ethanol fermentation-conversion process, comprising:
a. an initial separation comprising separating a fermentation-derived stream into a final separation feed stream and a heavy phase discharge stream using at least a first initial separation device, wherein the final separation feed stream comprises more light phase than the heavy phase discharge stream and the heavy phase discharge stream comprises more heavy phase than light phase;
b. a final separation comprising separating the final separation feed stream into an oil-containing stream and a recycle stream using at least a first oil-recovery separation device;
c. recycling the recycle stream into a feed stream for the initial separation; and,
d. recovering ethanol from the heavy phase discharge stream.
2. A method according to claim 1 , wherein the initial separation comprises a first initial separation using a first initial separation device and a second initial separation using a second initial separation device.
3. A method according to claim 2 , wherein the fermentation-derived stream comprises an emulsion and the process further comprises breaking the emulsion prior to the final separation.
4. A method according to claim 2 , wherein the first initial separation produces a dirty light phase feed stream and a clean heavy phase discharge stream from the fermentation-derived stream, the second separation produces the final separation feed stream and an enriched discharge stream from the dirty light phase discharge stream, and the final separation produces a clean light phase stream, which is the oil-containing stream, and a dirty heavy phase stream, which is the recycle stream.
5. A method according to claim 4 , wherein the enriched discharge stream is recycled into the fermentation-derived stream for use as a feed stream for the first initial separation.
6. A method according to claim 2 , wherein the first initial separation device is an inner-rising disk-stack centrifuges, the second initial separation device is a center-rising disk-stack centrifuge and the final oil-recovery separation device is an outer-rising disk-stack centrifuge.
7. A method according to claim 1 , wherein the fermentation-derived stream comprises an amount of solids, and the method further comprises reducing the amount of solids in the fermentation-derived stream prior to the initial separation.
8. A method according to claim 7 , further comprising washing a solids-containing stream with at least a portion of the heavy phase discharge stream to recover light phase and recycling the recovered light phase into the solids-reduced fermentation-derived stream.
9. A method according to claim 1 , wherein the fermentation-derived stream is chosen from beer, whole stillage, thin stillage, and syrup.
10. A method according to claim 9 , wherein the fermentation-derived stream is beer and the feedstock is corn.
11. A method according to claim 1 , wherein the separation devices are chosen from decanters and centrifuges.