Michael Pirc

Date of Award


Document Type


Degree Name

Master of Science (MS)


Chemical Engineering


The feasibility of liquid extraction as an economic alternative to the ternary azeotrope distillation of an ethanol-water fermenta tion mixture was studied. Experimentation included the determination of the attractiveness of the potential solvents "Freon" TF, 1-pentene, ethyl ether, unleaded gasoline, and #2 diesel fuel. Selectivities and distribution coefficients for these solvents were determined. Analysis included generation of a process flowsheet and the resultant energy requirements and process economics.

Unleaded gasoline was selected aver #2 diesel fuel as the more attractive solvent based on the distribution coefficients, and "Freon" TF, 1-pentene, and ethyl ether were ruled out as potential solvents.

A fermentation plant incorporating a gasoline extraction process and a beer still to separate the fermentation mixture, with an ethanol recovery rate of 96 wt%, was found to yield an energy savings of 15.6% over a fermentation plant equipped with only a ternary azeotrope dis tillation separation process. Annual cost for this extraction scheme was found to be $3,998,600, as compared to an annual cost of $1,501,400 for the distillation process. Increasing the recovery rate of ethanol to greater than 99 wt% for the extraction process was suggested as a means to vastly improve its economics.

An extraction scheme that did not include the beer still to preconcentrate the alcohol was found to be uneconomical.