Mesophilic anaerobic digestion of corn thin stillage: A technical and energetic assessment of the corn-to-ethanol industry integrated with anaerobic digestion

Po Heng Lee, Jaeho Bae, Jeonghwan Kim, Wen Hsing Chen

Research output: Journal article publicationJournal articleAcademic researchpeer-review

37 Citations (Scopus)

Abstract

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 CH4 g-1 VSfed (0.77 L g-1 VSremoved) 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.
Original languageEnglish
Pages (from-to)1514-1520
Number of pages7
JournalJournal of Chemical Technology and Biotechnology
Volume86
Issue number12
DOIs
Publication statusPublished - 1 Dec 2011
Externally publishedYes

Keywords

  • Anaerobic digestion
  • Ethanol
  • Methane
  • Thin stillage
  • Volatile solid

ASJC Scopus subject areas

  • Biotechnology
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Waste Management and Disposal
  • Pollution
  • Organic Chemistry
  • Inorganic Chemistry

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