Scott Stampe

Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Agricultural Engineering

First Advisor

Darrell W. De Boer


Steam consumption associated with the small-scale fractional distillation of ethanol at the South Dakota State University Alcohol Fuels Research Facility has been determined. During 1981, seven, ten, and thirteen percent ethanol concentrations in corn-beer were distilled to a 92.5 percent fuel ethanol product. Residual ethanol concentrations in spent stillage were studied at average levels of 0.13, ' 0.15, and 0.30 percent by volume. The total system energy requirement averaged 3.88 rnegajoules per liter (13,900 Btu per gallon) of anhydrous-equivalent ethanol, exclusive of boiler efficiency. Emperical relationships were established between the distillation energy requirement and two operating parameters. These parameters were studied in two independent experiments. In experiment one, "center stripper temperature" served as an indicator of the parameter "stillage residual ethanol concentration." The former demonstrated an inverse, linear relationship (R2 = 0.88) with the energy requirement of distillation when combined with the variables "center rectifier temperature" and "product flow rate." In the second experiment, the parameter "com-beer ethanol concentration" demonstrated an inverse, quadratic relationship (R 2 = 0.99) with the energy requirement of distillation. The total steam energy requirement was partitioned into components. Heating of the corn-beer required 20 percent; relux generation, 38 percent; product condensation, 18 percent; and system thermal losses absorbed the remaining 24 percent of total energy consumption .It is the intent of this thesis to focus on one facet of the technical aspect of ethanol production. The emphasis lies with the examination of the magnitude and makeup of the steam consumption of the typical distillation process that separates ethanol from a corn and water slurry. The evaluations are based upon operation of a small, commercial, 30.5 centimeter (12.0 inch) diameter distillation tower at the South Dakota State University Alcohol Fuels Laboratory during 1981.

Library of Congress Subject Headings

Alcohol as fuel



Number of Pages



South Dakota State University