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U.S. Department of Energy
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Economic evaluation of neutral-solvents fermentation product separation

Technical Report ·
OSTI ID:6217003

An evaluation of a neutral-solvents fermentation process was made for comparison with ethanol fermentations, concentrating on performing a simplified separation process design and laying the groundwork for future rigorous calculations. A 150 x 10/sup 6/ kg/y fermentation-product stream containing 1-butanol, acetone, ethanol, and water was used as the feed to the separation scheme. Equipment costs were substantially less than ethanol-recovery equipment costs for an identical solvents capacity. In preparation for rigorous separation calculations, parameters for the modified UNIQUAC algorithm for estimating liquid activity coefficients were developed. The overall economics of a neutral-solvents plant were compared with ethanol-fermentation-plant design data by determining the selling price to produce a 15% return on investment assuming equal fermentation costs for both processes. The selling price for neutral solvents from corn, at 48 cents/kg ($1.44/gal), was less than both that for ethanol from corn, 63 cents/kg ($1.89/gal), and the present neutral-solvents market price, 74 cents/kg ($2.22/gal). Furthermore, the neutral-solvents-plant thermal efficiency is higher than the ethanol plant efficiency (91% versus 62%). A sensitivity analysis indicated that the selling price is affected most by raw materials costs, by-product credits, and fermentation equipment costs; thus, the current analysis should be complemented by detailed investigations of these costs.

Research Organization:
Oak Ridge National Lab., TN (USA); Massachusetts Inst. of Tech., Oak Ridge, TN (USA). School of Chemical Engineering Practice
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
6217003
Report Number(s):
ORNL/MIT-330; ON: DE81027076
Country of Publication:
United States
Language:
English