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Process design and economic studies of alternative fermentation methods for the production of ethanol
Author(s) -
Cysewski Gerald R.,
Wilke Charles R.
Publication year - 1978
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260200908
Subject(s) - fermentation , ethanol fuel , production (economics) , pulp and paper industry , ethanol fermentation , yeast , ethanol , capital investment , investment (military) , continuous production , capital cost , process engineering , substrate (aquarium) , chemistry , microbiology and biotechnology , environmental science , food science , economics , engineering , biochemistry , biology , environmental engineering , microeconomics , ecology , finance , politics , law , political science , macroeconomics
Cell recycle and vacuum fermentation processes are described for the continuous production of ethanol. Preliminary process design studies are employed to make an economic comparison of these alternative fermentation schemes with continuous and batch fermentation technologies. Designs are based on a production capacity of 78,000 gal 95% ethanol (EtOH)/day employing molasses as the fermentation substrate. The studies indicate that a 57% reduction in fixed capital investment is realized by continuous rather than batch operation. Further decreases in required capital investment of 68 and 71% over batch fermentation were obtained for cell recycle and vacuum operation, respectively. However, ethanol production costs were dominated by the cost of molasses, representing over 75% of the total manufacturing cost. But, when a reasonable yeast by‐product credit was assumed, the net production cost for 95% ethanol was estimated at 82.3 and 80.6 cent/gal, for the cell recycle and vacuum processes, respectively.