Farm-scale production of fuel ethanol and wet grain from corn in a batch process
The batch production of fuel grade ethanol and distillers' wet grain (wet solids) in a farm-scale process (1240-15,580 L/batch) is described. The procedure employs yeast fermentation of amylase-treated corn mash and a two-stage distillation. Primary emphasis in this study was on the cooking, fermentation, and centrifugation steps. Without recycling, fermentation of the mash yielded beers with 10.0-10.5% ethanol. Recycling of stillage supernatant at full, 75, or 50% strengths produced enriched mashes that after 48-h fermentation yielded beers with 5-14% more ethanol. Recycling twice with full-strength stillage supernatant at pH 7.0 increased the ethanol yield in the final beer 16.5%; however, the time to complete the final fermentation was extended from 48 to 72 h and salt buildup occurred. By recycling at pH 5.4, it was possible to avoid rapid salt buildup and obtain beers with 10.3-10.5% ethanol. Recycling resulted in increased levels of glucose, starch, crude protein, and fat in the beer and a reduced moisture content while the wet solids showed an increased starch content. Centrifugation after cooking or fermentation instead of after distillation reduced the mash volume 17-20% and this lowered the ethanol yield in the subsequently produced beer. Fermentation of a volume-restored mash supernatant gave a beer with only 9.25% ethanol. Mash wet solids varied somewhat chemically from beer and stillage solids. An economic and energy balance analysis of various modes of plant operation are provided and plant design considerations are suggested.
- Research Organization:
- Department of Microbiology and Alcohol Fuel Research Laboratory, South Dakota State University, Brookings, South Dakota 57007
- OSTI ID:
- 6459808
- Journal Information:
- Biotechnol. Bioeng.; (United States), Journal Name: Biotechnol. Bioeng.; (United States) Vol. XXIV:7; ISSN BIBIA
- Country of Publication:
- United States
- Language:
- English
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Fuel ethanol and high protein feed from corn and corn-whey mixtures in a farm-scale plant
Fuel ethanol and high protein feed from corn and corn-whey mixtures in a farm-scale plant
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ALCOHOLS
BIOCONVERSION
CEREALS
ETHANOL
FERMENTATION
FUNGI
GRAMINEAE
GRASS
HYDROXY COMPOUNDS
MAIZE
MICROORGANISMS
ORGANIC COMPOUNDS
PLANTS
PRODUCTION
SOLIDS
YEASTS