Distillers Corn Oil

About This Product

Distillers corn oil, usually abbreviated DCO, is separated by centrifuge from the thin stillage that remains after corn has been fermented to ethanol. It is not pressed from the grain as an oil crop would be; the starch has already been converted, and the oil is recovered from what is left. It is supplied as a dark, unrefined liquid with free fatty acid typically between 5 and 15 percent. Its commercial position rests on classification as much as chemistry. Because it is a residue of an existing process rather than a purpose-grown crop, it is treated as a waste or residue feedstock under RED II and comparable schemes, which attracts stronger incentives and avoids the land-use scrutiny applied to virgin vegetable oils. Chemically it resembles corn oil, dominated by linoleic and oleic acid, so the resulting ester has reasonable cold flow and moderate oxidation stability. The processing constraints come from its residue origin: high free fatty acid rules out straightforward alkali transesterification and requires acid esterification or pretreatment, and it carries sulphur, phosphorus and metals from the fermentation stream that must be removed before hydrotreating. It is used for FAME biodiesel, hydrotreated renewable diesel, HEFA aviation pathways and in animal feed. Bio Green Fuels supplies distillers corn oil to specification on free fatty acid, moisture and impurities, sulphur, phosphorus, metals and unsaponifiable matter, with ISCC certification available.