Tag Archives: bioethanol

848–858 V. Rooni, M. Raud and T. Kikas
Technical solutions used in different pretreatments of lignocellulosic biomass: a review
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Technical solutions used in different pretreatments of lignocellulosic biomass: a review

V. Rooni, M. Raud and T. Kikas*

Estonian University of Life Sciences, Institute of Technology, 56 Kreutzwaldi Str., EE 51014 Tartu, Estonia
*Correspondence: timo.kikas@emu.ee

Abstract:

Bioethanol production from lignocellulosic biomass has attracted a lot of attention as one of the most promising alternative to liquid fossil fuels. Over the last decades a lot of research has been done to find the optimal methods & devices to produce bioethanol from all kind of lignocellulosic biomass. A traditional three-step production process is used to produce bioethanol from lignocellulosic biomass – pretreatment, enzymatic hydrolysis, & fermentation. Today, the high cost of the pretreatment prevents bioethanol from competing with petrol. In this review article, the positive & negative aspects of different pretreatment methods & patented devices are investigated & analysed. Based on the analysis several options on how to lower lignocellulosic biomass pretreatment costs & how to increase the competitiveness of bioethanol are proposed.

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729-736 A. Jäger,, C. Nicoletti and K. Krennhuber
Evaluation of the inline stripping of ethanol during cyanobacteria cultivation in a bubble column bioreactor
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Evaluation of the inline stripping of ethanol during cyanobacteria cultivation in a bubble column bioreactor

A. Jäger¹,*, C. Nicoletti² and K. Krennhuber¹

¹ University of Applied Sciences Upper Austria, Faculty of Engineering, Department of Bio & Environmental Technology, Stelzhamerstr. 23, AT4600 Wels, Austria
² University of Calabria, Via P. Bucci, IT87036 Rende (CS), Italy
*Correspondence: a.jaeger@fh-wels.at

Abstract:

Cyanobacteria are oxygenic phototrophic microorganisms capable of photosynthesis. In this redox reaction driven by light energy, carbon dioxide and water are converted into chemical energy in form of carbohydrates and oxygen. The output of this process is restricted by product inhibition from the bioethanol. Here, we evaluate a method of ethanol stripping in a bubble column for perspective use for determination of ethanol production rate of engineered cyanobacteria. The knowledge about the amount of condensation and recovery rate combined with HPLC measurement for ethanol determination can be used to specify the real amount of produced ethanol (absolute) by cyanobacteria in the used bioreactor. Stripping and recovery rate are depending on several parameter like flow rate, initial ethanol concentration, condensation temperature etc. Due to the high influence of these parameters they have to be supposed to be static regarding to the degrees of freedom.
To evaluate the system different ethanol concentration were testet for stripping and determination of recovery rate. As the stripping rate was much higher compared to the ethanol production rate with our Synechococcus elongatus PCC 7942 the medium was spiked with ethanol to varying concentrations of 0.5, 1 and 2% v/v. It could be shown that ethanol could be removed quantitavely. Removal rates of 97 98% were reached with initial ethanol concentrations of 5 g L-1 to 20 g L-1. The results demonstrated determination of ethanol in the exhaust air stream and quantitavely recollection by cultivating engineered Synechococcus elongatus in bubble column bioreactors.

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569–578 M. Raud, V. Rooni and T. Kikas
Explosive decompression pretreatment: nitrogen vs. compressed air
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Explosive decompression pretreatment: nitrogen vs. compressed air

M. Raud*, V. Rooni and T. Kikas

Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56
EE51014 Tartu, Estonia
*Correspondence: merlin.raud@emu.ee

Abstract:

Lignocellulosic material is the most promising feedstock for the bioethanol production however, due to complicated physico-chemical characteristics of biomasses, it is necessary to pretreat the biomass before the bioethanol production. The goal of the pretreatment is to open the biomass structure for enzymatic hydrolysis to gain higher sugar and ethanol yields in further processes. In this paper a novel explosive decompression pretreatment is studied where two gases – nitrogen and compressed air are utilized for pressure generation. For this, traditional three-step bioethanol production process was used, where explosive decompression pretreatment with N2 gas or compressed air was applied for biomass pretreatment. Glucose and ethanol concentrations were measured during the process. Glucose and ethanol yields and process efficiencies were used to evaluate the effect of explosive decompression pretreatment and its suitability for biomass pretreatment in bioethanol production process. Results show that the highest glucose yield was gained when nitrogen gas was used, while difference in glucose yield compared to that of autohydrolysis was negligible when compressed air was applied.

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174–180 F. Pfannerer, K. Krennhuber, A. Jäger and H. Kahr
New constructs for ethanol production via cyanobacteria
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New constructs for ethanol production via cyanobacteria

F. Pfannerer¹, K. Krennhuber¹, A. Jäger¹ and H. Kahr¹*

¹University of Applied Sciences Upper Austria, R&D, Franz-Fritsch-Straße 11,
AT 4600 Wels, Austria
*Correspondence: Heike.Kahr@fh-wels.at

Abstract:

Alternatives to fossil fuels must be developed due to several already known reasons. Bioethanol can be an attractive energy concept. Bioethanol gasoline hybrid fuel can be used by most internal combustion engines. First and second generation bioethanol production is already available – here agricultural crops or residues are utilised. There are controversial discussions about these bioethanol production methods – the food versus fuel debate, cost and energy efficiency. Alternative advanced bioethanol production must be established with competitive production costs. Photosynthetic prokaryotes like cyanobacteria are attractive organisms for this purpose – these prokaryotes are fast growing organisms and utilize solar energy and CO2. But these prokaryotes must be genetically manipulated for ethanol production. In this study transformation was performed using homologous recombination to introduce the pyruvate decarboxylase (pdc) and alcohol dehydrogenase B (adhB) genes  of Zymomonas mobilis into the photosynthetic prokaryote Synechococcus elongatus PCC 7942 genome. These cyanobacteria grow in fresh water and seawater or even in wastewater. Both genes were expressed under the control of the strong constitutive promoter of psbA1 gene (encoding photosystem II protein D1). Various cloning strategies were done. Each construct was transformed successful in Synechococcus elongatus PCC 7942 and the potential bioethanol production was determined with HPLC. Only one construct produces bioethanol at detectable level. Diverse reactors and scale up steps were done to increase the bioethanol production. Anyhow further cloning strategies must be implemented to improve the production rate to achieve an effective bioethanol production from Synechococcus elongatus PCC 7942.

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577-584 T. Kotek,, M. Kotek, P. Jindra and M. Pexa
Determination of the optimal injection time for adaptation SI engine on E85 fuel using self-designed auxiliary control unit
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Determination of the optimal injection time for adaptation SI engine on E85 fuel using self-designed auxiliary control unit

T. Kotek¹,*, M. Kotek², P. Jindra² and M. Pexa¹

¹Czech University of Life Science Prague, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ16521 Prague, Czech republic; *Correspondence: kotek@oikt.czu.cz
²Czech University of Life Science Prague, Faculty of Engineering, Department of Vehicles and Ground Transport, Kamýcká 129, CZ16521 Prague, Czech republic

Abstract:

Article deals with problems of the operation of spark ignition combustion engine on high-percentage of blend bioethanol. The aim of the experiment was to find the optimal value of injection time of the engine injection valves with respect to the adaptive ability of the original engine control unit (ECU) when using a special auxiliary control unit (ACU) was adjusted injection time. Special dynamic driving cycle has been designed to assess the effects of prolonged injection time on the adaptive abilities of the ECU that stemmed from a real recording vehicle’s rides with the same engine as was used in conducted experiments. The results proved that by changing the extension of the period of injection occurs a gradual adaptation of the original ECU, but this adaptation is gradual and underway predominantly in modes functional closed-loop control, thus in modes of low to medium of loads. Results of the experiment provide determination of the efficient frontier of the percentage extension injection time with regard to adaptive abilities of original ECU.

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405-412 M. Raud, M. Tutt, J. Olt and T. Kikas
Effect of lignin content of lignocellulosic material on hydrolysis efficiency
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Effect of lignin content of lignocellulosic material on hydrolysis efficiency

M. Raud, M. Tutt, J. Olt and T. Kikas*

Estonian University of Life Sciences, Institute of Technology, Kreutzwaldi 56, EE51014 Tartu, Estonia; *Correspondence: timo.kikas@emu.ee

Abstract:

Lignocellulosic material is the most promising feedstock for bioethanol production; however, due to the varying physicochemical characteristics of different biomasses, it is necessary to select a biomass with a composition suitable for bioethanol production. For this purpose several different alternative non-food energy crops were chosen to investigate their suitability for bioethanol production, considering their cellulose, hemicellulose and lignin content. The traditional three-step bioethanol production process was used, where dilute acid was applied for biomass pre-treatment. Glucose and ethanol concentrations were measured during the process. Glucose and ethanol yields and hydrolysis efficiency were used to evaluate the suitability of different energy crops for bioethanol production. The results show that, with most biomass types, the glucose yield increases as the cellulose content in the biomass rises. However, a sharp decrease in hydrolysis efficiency was noted in the lignin content range of 7 to 9 g 100 g-1. The lower hydrolysis efficiency also resulted in a lower ethanol yield in the next step of the bioethanol production process for these samples.

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550-557 V. Hönig,, Z. Linhart, J. Táborský and J. Mařík
Determination of the phase separation temperature and the water solubility in the mixtures of gasoline with biobutanol and bioethanol
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Determination of the phase separation temperature and the water solubility in the mixtures of gasoline with biobutanol and bioethanol

V. Hönig¹,*, Z. Linhart², J. Táborský¹ and J. Mařík³

¹Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamycka 129, CZ16521, Prague 6, Czech Republic; *Correspondence: honig@af.czu.cz
²Czech University of Life Sciences Prague, Faculty of Economics and Management, Department of Management, Kamycka 129, CZ16521, Prague 6, Czech Republic
³Czech University of Life Sciences Prague, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamycka 129, CZ16521, Prague 6, Czech Republic

Abstract:

Original hydrocarbon composition, volatility, compatibility with materials, calorific value and stability of the mixture in the presence of water are monitored usually. This paper deals with the stability of gasoline-biobutanol and gasoline-bioethanol mixtures in the presence of water. Biobutanol is better biofuel than bioethanol using the same raw materials. Different contents of alcohol and oxygenated cosolvents are evaluated. Experimental analysis are focused on the water solubility and phase stability. Solubility in water of butanol and ethanol mixtures is very similar. Butanol-gasoline mixture provides better phase stability upon contact with water or atmospheric moisture oppose to ethanol mixtures. Butanol also does not enter to the aqueous layer and fuel properties remain in phase separation preserved. Further, it was found that crystals occur at low temperatures after exclusion of water was seen. Moreover, the temperature of phase separation can affect the content of alcohol, water, hydrocarbon composition and cosolvents added. The only difference found between more beneficial butanol and less beneficial ethanol was ABE (Aceton–Butanol–Ethanol) fermentation with Clostridium Acetobutylicum allowing to ferment also saccharidic cellulose to biobutanol according to standard of second generation biofuels.

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558-567 V. Hönig,, M. Orsák, M. Pexa and Z. Linhart
The distillation characteristics of automotive gasoline containing biobutanol, bioethanol and the influence of the oxygenates
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The distillation characteristics of automotive gasoline containing biobutanol, bioethanol and the influence of the oxygenates

V. Hönig¹,*, M. Orsák¹, M. Pexa² and Z. Linhart³

¹Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamycka 129, CZ16521, Prague 6, Czech Republic; *Correspondence: honig@af.czu.cz
²Czech University of Life Sciences Prague, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamycka 129, CZ16521, Prague 6, Czech Republic
³Czech University of Life Sciences Prague, Faculty of Economics and Management, Department of Management, Kamycka 129, CZ16521, Prague 6, Czech Republic

Abstract:

Bioethanol and fatty acid methyl esters are a regular part of the production of gasoline and diesel fuels, although in limited quantities. Introduction of bioethanol as part of automobile gasoline was associated with high production costs, technical and logistical problems. This article analyses changes of distillation curve of biobutanol and isobutanol as an alternative to bioethanol. Added alcohol to gasoline causes reduction of boiling point due to the formation of azeotrope. This phenomena of distillation curve are called Plato effect. Therefore, ethers (MTBE and ETBE) are added to fuel to affect the most central part of distillation curve. Especially, to decrease the distillation temperature oppose to gasoline without oxygenates of wide range of distilled volume. This article replaces simple universal models predicting properties of alcohol-gasoline mixtures. It was found that mixture of ETBE with bioethanol in gasoline the distillation curve summarise its effects. Butanol and MTBE influence distillation curve of gasoline only in values of its boiling points. Therefore, butanol is mixable with all listed fuel components without any additional addaptations.

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568-576 V. Hönig, M. Orsák and J. Táborský
The analysis of the influence of biobutanol and bioethanol mixture with ethers on the vapour pressure of gasoline
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The analysis of the influence of biobutanol and bioethanol mixture with ethers on the vapour pressure of gasoline

V. Hönig*, M. Orsák and J. Táborský

Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamycka 129, CZ16521 Prague 6, Czech Republic; *Correspondence: honig@af.czu.cz

Abstract:

In addition to widely known species automotive fuels that are currently on the market, there are many other chemicals which are used or can be used as fuels or fuel components for current automotive internal combustion engines. Implementation of such ingredients car brings a number of technical problems. The vapour pressure is the pressure in the system in which they are at a certain temperature gaseous and liquid phases in equilibrium. The addition of alcohols such as gasoline constituents significantly affects the volatility of the resulting mixture. The article is focused on assessing the addition of biobutanol as n–butanol or isobutanol vapour pressure compared to the already commonly used in bioethanol. Also included is the possibility to use ethers for influencing the vapour pressure of the resulting mixture. Part of the experiment is to assess the influence of the quantity and type of oxygenates and composition of gasoline. Based on the measured data it is clear that addition of alcohol to gasoline create complications. Effect biobutanol as possible alternatives is different than bioethanol. It is therefore necessary to take into account the influence of alcohol, even at low concentrations corresponding to the limit according to standard EN 228. Biobutanol compared bioethanol can be used as 100% fuel. For the low vapour pressure of the fuel experiment also aims to increase its value using pentane.

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577-584 T. Kotek,, M. Kotek, P. Jindra and M. Pexa
Determination of the optimal injection time for adaptation SI engine on E85 fuel using self-designed auxiliary control unit
Abstract |
Full text PDF (241 kB)

Determination of the optimal injection time for adaptation SI engine on E85 fuel using self-designed auxiliary control unit

T. Kotek¹,*, M. Kotek², P. Jindra² and M. Pexa¹

¹Czech University of Life Science Prague, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ16521 Prague, Czech republic; *Correspondence: kotek@oikt.czu.cz
²Czech University of Life Science Prague, Faculty of Engineering, Department of Vehicles and Ground Transport, Kamýcká 129, CZ16521 Prague, Czech republic

Abstract:

Article deals with problems of the operation of spark ignition combustion engine on high-percentage of blend bioethanol. The aim of the experiment was to find the optimal value of injection time of the engine injection valves with respect to the adaptive ability of the original engine control unit (ECU) when using a special auxiliary control unit (ACU) was adjusted injection time. Special dynamic driving cycle has been designed to assess the effects of prolonged injection time on the adaptive abilities of the ECU that stemmed from a real recording vehicle’s rides with the same engine as was used in conducted experiments. The results proved that by changing the extension of the period of injection occurs a gradual adaptation of the original ECU, but this adaptation is gradual and underway predominantly in modes functional closed-loop control, thus in modes of low to medium of loads. Results of the experiment provide determination of the efficient frontier of the percentage extension injection time with regard to adaptive abilities of original ECU.

Key words:

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