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Industrial symbiosis: Corn ethanol fermentation, hydrothermal carbonization, and anaerobic digestion
Author(s) -
Wood Brandon M.,
Jader Lindsey R.,
Schendel Frederick J.,
Hahn Nicholas J.,
Valentas Kenneth J.,
McNamara Patrick J.,
Novak Paige M.,
Heilmann Steven M.
Publication year - 2013
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.24924
Subject(s) - stillage , biogas , anaerobic digestion , pulp and paper industry , hydrothermal carbonization , biofuel , chemistry , biorefinery , bioenergy , chemical oxygen demand , methane , fermentation , waste management , carbonization , food science , wastewater , organic chemistry , adsorption , engineering
The production of dry‐grind corn ethanol results in the generation of intermediate products, thin and whole stillage, which require energy‐intensive downstream processing for conversion into commercial animal feed products. Hydrothermal carbonization of thin and whole stillage coupled with anaerobic digestion was investigated as alternative processing methods that could benefit the industry. By substantially eliminating evaporation of water, reductions in downstream energy consumption from 65% to 73% were achieved while generating hydrochar, fatty acids, treated process water, and biogas co‐products providing new opportunities for the industry. Processing whole stillage in this manner produced the four co‐products, eliminated centrifugation and evaporation, and substantially reduced drying. With thin stillage, all four co‐products were again produced, as well as a high quality animal feed. Anaerobic digestion of the aqueous product stream from the hydrothermal carbonization of thin stillage reduced chemical oxygen demand (COD) by more than 90% and converted 83% of the initial COD to methane. Internal use of this biogas could entirely fuel the HTC process and reduce overall natural gas usage. Biotechnol. Bioeng. 2013;110: 2624–2632. © 2013 Wiley Periodicals, Inc.