PROCESSES AND SYSTEMS FOR DRY-MILLED CORN ETHANOL AND CORN OIL PRODUCTION WITH IMPROVED CARBON FOOTPRINT

摘要

The present invention improves corn dry milling in several ways. Integrated corn biorefinery processes are disclosed which can produce ethanol, edible corn oil, DDG or DDGS, solvent-extracted meal, power, and optionally crude corn oil, starting from corn. Some variations employ corn fractionation and edible corn oil recovery using liquid carbon dioxide, avoiding hazardous hydrocarbon-based solvents to produce edible corn oil. Some variations employ integration of gas-fired co-generation into the dry-milled corn ethanol plant to significantly reduce energy usage and carbon footprint associated with the overall process. Counter-current drying is preferably employed to produce a high-quality DDG or DDGS product with high protein content, low mycotoxin content, and low residual ethanol content.

主权项

1. A process for drying a solids-rich still residue derived from corn, said process comprising:
(a) introducing corn-derived glucose to an aqueous fermentor containing a microorganism to ferment glucose into a dilute fermentation product and carbon dioxide; (b) introducing said dilute fermentation product to a distillation unit configured to generate a distillate (overhead) and a solids-rich still residue (still bottoms); (c) drying said solids-rich still residue using a drying gas in a counter-current dryer disposed in a vertically stacked dryer, to generate a dried solids stream; (d) cooling said dried solids stream using a cooling gas in a cooler disposed in communication with said vertically stacked dryer, to generate a cooled solids stream comprising distillers' dried grains with solubles (DDGS); and (e) recovering said DDGS.