Converting Waste Agricultural Biomass into a Resource - UNEP

Broin Fractionation (BFRAC) 218
USA, Pilot
Crop
Residue
Process
Equipment
Main Product
By-products
Corn, Switchgrass, wood
corn stalks, switch grass, wood chips
Corn fractionation and Lignocellulosic Conversion
Technology
Bio-refinery plant
Ethanol
Value-added co-products, including Dakota Gold
HP (TM), Dakota Bran (TM) Cake, and Dakota
Gold Corn Germ Dehydrated (TM) that is being
further processed to create defatted corn germ
meal and edible corn oil. 219
Technical Description of Technology:
The process uses enzymes that convert starch to sugar without cooking.
Here's how it works.
Milling. The feedstock passes through a hammer mill, which grinds it into a
fine powder called flour.
Fermentation. Fermentation: Enzymes are added to convert starch into
glucose, or simple sugars. Yeast is added to the mash to convert the sugars
to ethanol and carbon dioxide. The mash is continually agitated and cooled
until the ethanol concentration has been maximized.
Distillation. Distillation: The fermented mash, now called beer, contains about
20% alcohol – significantly above the industry standard - plus all the nonfermentable
solids from the corn and yeast cells. The mash is pumped to the
continuous flow, multi-column distillation system where the ethanol is
removed from the solids and the water. The ethanol leaves the top of the final
column at about 95% concentration, and the residue mash, called stillage, is
transferred from the base of the column to the co-product processing area.
Dehydration. The alcohol from the top of the column passes through a
dehydration system where the remaining water will be removed. Most ethanol
plants use a molecular sieve to capture the last bit of water in the ethanol. The
alcohol product at this stage is called anhydrous ethanol (pure, without water)
and is approximately 200 proof.
218 http://www.poetenergy.com/learn/process.asp
219 http://www.allbusiness.com/legal/intellectual-property-patent/1045974-1.html
400