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Recirculation of process water in the production of ethanol from softwood

Larsson, M; Galbe, Mats LU and Zacchi, Guido LU (1997) In Bioresource Technology 60(2). p.143-151
Abstract
In the production of ethanol from lignocellulosics, large quantities of water are needed in various process steps. In industrial processes, recycling of process streams is necessary to minimise fresh water requirements and decrease the amount of wastewater produced. This leads to increases in various substances, both volatile and non-volatile which inhibit fermentation. In the present Study ethanol was produced from softwood in a bench-scale process development unit. The stillage stream from the distillation step was fractionated by evaporation and various evaporation fractions characterised and their inhibitory effect on fermentation investigated. irt was found that the volatile fractions have no negative effect on the fermentation while... (More)
In the production of ethanol from lignocellulosics, large quantities of water are needed in various process steps. In industrial processes, recycling of process streams is necessary to minimise fresh water requirements and decrease the amount of wastewater produced. This leads to increases in various substances, both volatile and non-volatile which inhibit fermentation. In the present Study ethanol was produced from softwood in a bench-scale process development unit. The stillage stream from the distillation step was fractionated by evaporation and various evaporation fractions characterised and their inhibitory effect on fermentation investigated. irt was found that the volatile fractions have no negative effect on the fermentation while the non-volatile fraction inhibited fermentation and resulted in a decreased yield. Simulation of a six-effect evaporation unit based on the experimental data shows that the intermediate evaporation condensate fractions are most suited for disposal. The chemical and biological oxygen demands are only about 10% of the value in the stillage stream. Evaporation has been shown to be an effective way to drastically diminish the build-up of inhibitory compounds when process streams are recirculated, but the energy demand is high. Various process configurations to reduce the energy demand are suggested. (C) 1997 Elsevier Science Ltd. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
ethanol, recirculation, inhibitory, bench-scale process development, unit, evaporation
in
Bioresource Technology
volume
60
issue
2
pages
143 - 151
publisher
Elsevier
external identifiers
  • wos:A1997XD91100007
  • scopus:0031149338
ISSN
1873-2976
DOI
10.1016/S0960-8524(97)00011-4
language
English
LU publication?
yes
id
9b399d8a-9dd6-40fc-bcbe-8469ff946cc3 (old id 3911482)
date added to LUP
2013-06-28 13:58:26
date last changed
2017-09-24 04:26:47
@article{9b399d8a-9dd6-40fc-bcbe-8469ff946cc3,
  abstract     = {In the production of ethanol from lignocellulosics, large quantities of water are needed in various process steps. In industrial processes, recycling of process streams is necessary to minimise fresh water requirements and decrease the amount of wastewater produced. This leads to increases in various substances, both volatile and non-volatile which inhibit fermentation. In the present Study ethanol was produced from softwood in a bench-scale process development unit. The stillage stream from the distillation step was fractionated by evaporation and various evaporation fractions characterised and their inhibitory effect on fermentation investigated. irt was found that the volatile fractions have no negative effect on the fermentation while the non-volatile fraction inhibited fermentation and resulted in a decreased yield. Simulation of a six-effect evaporation unit based on the experimental data shows that the intermediate evaporation condensate fractions are most suited for disposal. The chemical and biological oxygen demands are only about 10% of the value in the stillage stream. Evaporation has been shown to be an effective way to drastically diminish the build-up of inhibitory compounds when process streams are recirculated, but the energy demand is high. Various process configurations to reduce the energy demand are suggested. (C) 1997 Elsevier Science Ltd.},
  author       = {Larsson, M and Galbe, Mats and Zacchi, Guido},
  issn         = {1873-2976},
  keyword      = {ethanol,recirculation,inhibitory,bench-scale process development,unit,evaporation},
  language     = {eng},
  number       = {2},
  pages        = {143--151},
  publisher    = {Elsevier},
  series       = {Bioresource Technology},
  title        = {Recirculation of process water in the production of ethanol from softwood},
  url          = {http://dx.doi.org/10.1016/S0960-8524(97)00011-4},
  volume       = {60},
  year         = {1997},
}