Corn Oil Extraction

Process Description

About 33% of each kernel of corn accepted by corn ethanol producers is converted into ethanol by mass through fermentation. The output of fermentation contains ethanol, water, protein, fiber, corn oil, ash, hemicellulose and other carbohydrates. This mixture is distilled to boil off the ethanol, leaving the remainder of the mixture in the bottom of the distillation stage. The distillation bottoms, or whole stillage, is conventionally subjected to centrifugation and evaporation to remove water prior to final drying.

GreenShift’s extraction technologies intercept the flow of the whole stillage at various points downstream of the distillation equipment and before drying. It’s technologies condition the stillage, extract corn oil, and return the stillage flow back to the ethanol producer for drying and grain production. The extracted corn oil is then stored and shipped for use as a biofuel or a commercial feed product.

GreenShift designed its technologies to extract oil in a way that decreases the ethanol facility's utility costs. All interconnections are plug-and-play, and the extraction equipment is often skid-mounted and capable of rapid installation or demobilization.

GreenShift’s extraction facilities are fully automated and designed to integrate into the client's computer control systems. GreenShift does not maintain any employees at its extraction facilities. Instead, routine maintenance and ongoing operations are handled by participating ethanol clients, any of which coordinate with GreenShift’s technical support staff, to ensure optimal performance.

GreenShift’s extraction technologies are grouped by methods: Method I, generally extracts corn oil from the concentrated thin stillage stream, and Method II, generally uses thin stillage to wash corn oil from within the wet cake stream allowing Method I to recover the increased amounts of corn oil within.

The whole stillage output from the distillation stage of the ethanol process is routed to centrifugation to remove water and solubles otherwise referred to as thin stillage. The thin stillage contains water, protein, ash, fiber, non-fermented carbohydrates and corn oil. The water content of thin stillage is reduced by evaporation in a multiple effect evaporator to produce a concentrated thin stillage, or syrup, consisting of approximately 40 weight percent solids (including corn oil). The syrup is conventionally combined with the solids from centrifugation of the whole stillage (the wet grains), and dried to produce distillers dried grains with solubles (DDGS).

Method I can achieve yields upwards of 1.0 lb/bu with aide of emulsion breakers while Method II can increase those yields to 1.5 lb/bu in some cases.