Combined process for ethanol fermentation at high-solids loading and biogas digestion from unwashed steam-exploded corn stover

Wang, Zhen; Lv, Zhe; Du, Jiliang; Mo, Chunling; Yang, Xing; Tian, Shen

doi:10.1016/j.biortech.2014.05.044

Cited by 26 publications

(9 citation statements)

References 27 publications

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“…• S4-Steam explosion (17 datasets from references [86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102] ): Primarily steam explosion without a catalyst, and in one case acid is used as the catalyst. Pretreated corn stover is subjected to enzymatic hydrolysis and then fermentation after washing with water.…”

Section: Technological Configurationsmentioning

confidence: 99%

Bioethanol from corn stover – Global warming footprint of alternative biotechnologies

Zhao

Damgaard

et al. 2019

Applied Energy

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Bioethanol from residual corn stover could contribute to lowering CO2 loads within the transport sector, if used as an amendment to gasoline. We modelled by life cycle assessment and Monte Carlo simulation seven different technological configurations for producing bioethanol from corn stover based on consistent mass flows and estimated ethanol production extracted from 141 datasets of reasonable quality. By parametrizing key processes and determining their statistical distribution based on actual data, we were able to estimate the Global Warming Potential (GWPs) for all the alternative technologies on a system level. Most of the individual cases showed a net saving in GWP when the savings obtained from recovering energy from anaerobic digestion of the liquid residues and incineration of the solid residues were included. The net savings could in some cases be as high as 900~1200 kg CO2-eq/t dry corn stover solids. If the residues were not subject to energy recovery, the production of bioethanol and use in gasoline would be a net load to global warming in more than 50% of the technological configurations. The "best-practice", defined as the top 15% cumulative probability with respect to GWP, suggests that technologies based on steam explosion and ammonia-based pretreatment appear statistically the most promising and could contribute, with residue energy recovery, to GWP savings of 850-1050 kg CO2-eq/t dry corn stover solids and produce in the range 178-216 kg of bioethanol. This paper provides insights into the key parameters for bioethanol production from corn stover and suggests areas for further research.

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Section: Technological Configurationsmentioning

confidence: 99%

Bioethanol from corn stover – Global warming footprint of alternative biotechnologies

Zhao

Damgaard

et al. 2019

Applied Energy

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“…To circumvent the difficulty of mixing at high WIS contents and achieve even distribution of enzymes and yeast, a short (1-3 h) fed-batch operation was introduced at the start of the experiment, and the solids concentration was increased gradually from 5 % to the desired WIS content. In a similar investigation, a short (6 h) prehydrolysis step was combined with long (36 h) fed-batch SSF using unwashed steam-pretreated corn stover; a final ethanol concentration of 70.7 g/L, corresponding to an ethanol yield of 72.5 %, was obtained at a solids content of as high as 35.5 % dry matter [36].…”

Section: Simultaneous Saccharification and Fermentationmentioning

confidence: 99%

“…Ethanol production at a high solids content (35.5 % dry matter, DM) and subsequent AD of whole stillage has been examined using unwashed steam-pretreated corn stover as raw material [36]. We have performed a similar study using wheat straw as raw material-instead using acetic acid to impregnate the wheat straw prior to pretreatment and separated the process streams to liquid and solid streams after pretreatment.…”

Section: Introductionmentioning

confidence: 99%

Combined production of biogas and ethanol at high solids loading from wheat straw impregnated with acetic acid: experimental study and techno-economic evaluation

Joelsson

Dienes

Kovács

et al. 2016

Sustain Chem Process

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Background: Production of ethanol and biogas from acetic acid-impregnated steam-pretreated wheat straw was investigated. The solid fraction after pretreatment was used at high solids concentrations to generate ethanol by simultaneous saccharification and fermentation (SSF). The residual streams were evaluated with regard to biogas production. The experimental results were used to perform a techno-economic evaluation of a biorefinery concerning ethanol, raw biogas, pellet, and electricity production at various solid contents and residence times in the fermentation step. The configurations were also altered to include biogas upgrading to vehicle fuel quality or fermentation of xylose to ethanol. Results:At a water-insoluble solids (WIS) content in the SSF of between 10 and 20 %, the ethanol yields exceeded 80 %, the highest being 86 % at 12.5 % WIS, expressed as % of the theoretical maximum, based on the glucan content in SSF. Anaerobic digestion of wheat straw hydrolysate and stillage yielded 4.8 and 1.0-1.2 g methane/100 g dry straw, respectively, in 7-day experiments. Maximum recovery of overall product was achieved when SSF was run at between 10 and 15 % initial WIS content, for which the product yields from 100 g dry wheat straw were 16.1-16.3 g ethanol, 5.8-6.0 g methane, and 25 g lignin-rich solid residue. The net present value (NPV) was negative at discount rate of 11 % but positive at 5 % discount rate for all configurations. The 20 % WIS configuration with a residence time of 96 h in the fermentation stage attained the highest NPV. The minimum ethanol selling price varied between 0.72 and 0.87 EUR/L ethanol when the biogas was unchanged and it decreased to between 0.46 and 0.60 EUR/L ethanol when the biogas was upgraded to vehicle fuel quality or when xylose was converted to ethanol. Conclusions:According to the techno-economic assessment, a process that is based on the fermentation of only hexoses to ethanol, and production of raw biogas from xylose is not profitable under the economic assumptions including 11 % discount rate in the evaluation. However, the profitability of a plant can be improved by biogas upgrading to vehicle fuel quality or fermentation of xylose to ethanol.

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“…Their application has thus been broadly studied to enhance anaerobic digestion yields and several research attempts have also dealt with the pre-processing of substrates destined to bio-ethanol production. In this view, the work of Wang et al [107] is particularly interesting. The authors treated chopped corn by steam explosion, performed at 2.0 MPa for 5 min.…”

Section: The Combination Of Bioethanol and Biogas Production Processesmentioning

confidence: 99%

Combined Biogas and Bioethanol Production: Opportunities and Challenges for Industrial Application

Cesaro

Belgıorno

2015

Energies

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Abstract:In the last decades the increasing energy requirements along with the need to face the consequences of climate change have driven the search for renewable energy sources, in order to replace as much as possible the use of fossil fuels. In this context biomass has generated great interest as it can be converted into energy via several routes, including fermentation and anaerobic digestion. The former is the most common option to produce ethanol, which has been recognized as one of the leading candidates to substitute a large fraction of the liquid fuels produced from oil. As the economic competitiveness of bioethanol fermentation processes has to be enhanced in order to promote its wider implementation, the most recent trends are directed towards the use of fermentation by-products within anaerobic digestion. The integration of both fermentation and anaerobic digestion, in a biorefinery concept, would allow the production of ethanol along with that of biogas, which can be used to produce heat and electricity, thus improving the overall energy balance. This work aims at reviewing the main studies on the combination of both bioethanol and biogas production processes, in order to highlight the strength and weakness of the integrated treatment for industrial application.

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Combined process for ethanol fermentation at high-solids loading and biogas digestion from unwashed steam-exploded corn stover

Cited by 26 publications

References 27 publications

Bioethanol from corn stover – Global warming footprint of alternative biotechnologies

Bioethanol from corn stover – Global warming footprint of alternative biotechnologies

Combined production of biogas and ethanol at high solids loading from wheat straw impregnated with acetic acid: experimental study and techno-economic evaluation

Combined Biogas and Bioethanol Production: Opportunities and Challenges for Industrial Application

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