An engineering economic evaluation of quick germ quick fiber process for dry-grind ethanol facilities

An engineering economic model which is mass balance and compositionally driven was developed to compare the conventional corn dry-grind process and the preseparation process called "Quick Germ/Quick Fiber" (QQ). The QQ process combines a wet milling front end with a dry-grind back end to recover the germ and coarse fiber (pericarp) before fermentation. In this model, the DDGS price was linked with its protein and fiber content as well as with the long term average relationship between DDGS, soybean meal, and corn prices. The detailed economic analysis showed that the payback time for the QQ plant retrofitted from conventional dry grind ethanol plant is only 1.01 years and the QQ process reduces the manufacturing cost of ethanol by 18.6 φ/gal. Sensitivity analysis was also conducted to compare retrofitted plant and conventional dry-grind plant overall revenue at different corn price, ethanol price, and corn compositions. Ethanol and feedstock price sensitivity analysis showed the QQ plant gains more profits when ethanol price increases, and are less sensitive to feedstock price change than conventional dry-grind ethanol plant. The payback time for the QQ process also varies depending on protein content in corn.