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Mesophilic anaerobic digestion of corn thin stillage: a technical and energetic assessment of the corn‐to‐ethanol industry integrated with anaerobic digestion
Author(s) -
Lee PoHeng,
Bae Jaeho,
Kim Jeonghwan,
Chen WenHsing
Publication year - 2011
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.2664
Subject(s) - stillage , anaerobic digestion , mesophile , pulp and paper industry , chemistry , methane , corn ethanol , biofuel , digestion (alchemy) , biogas , digestate , bioenergy , waste management , hydraulic retention time , anaerobic exercise , ethanol fuel , food science , sewage treatment , chromatography , fermentation , engineering , biology , physiology , organic chemistry , bacteria , genetics
BACKGROUND: The purpose of this study was to reduce the VS (volatile solid) and recover energy (methane) from thin stillage through mesophilic anaerobic digestion in corn–ethanol plants. The performance of a continuously stirred tank reactor (CSTR) with different hydraulic retention times (HRTs) was evaluated in this study. RESULTS: The results show no differences in volatile solid (VS) destruction (82–83%) in the reactor with HRTs ranging from 25 to 40 days. The maximum volumetric methane production rate of 1.41 L L −1 day −1 was produced at 25‐day HRT, whereas the maximum methane yield of approximately 0.63 L CH 4 g −1 VS fed (0.77 L g −1 VS removed ) was achieved with HRTs between 30 and 40 days. Simulation results using a kinetic model indicate that the reactor needs to be operated for longer than 23 days in order to achieve 80% of maximum methane yield. The techno‐economic potential of a corn–ethanol facility to produce an estimated 57% energy recovery using mesophilic anaerobic digestion has long been overlooked. A corn–ethanol plant integrated with mesophilic anaerobic digestion increases the net energy balance ratio from 1.26 to 1.80. CONCLUSION: Mesophilic anaerobic digestion complements the corn–ethanol business so that the sustainable energy obtained from corn recovery is made more lucrative and renewable. Copyright © 2011 Society of Chemical Industry