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Energy and Environmental Performance of Bioethanol from Different Lignocelluloses  [PDF]
Lin Luo,Ester van der Voet,Gjalt Huppes
International Journal of Chemical Engineering , 2010, DOI: 10.1155/2010/740962
Abstract: Climate change and the wish to reduce the dependence on oil are the incentives for the development of alternative energy sources. The use of lignocellulosic biomass together with cellulosic processing technology provides opportunities to produce fuel ethanol with less competition with food and nature. Many studies on energy analysis and life cycle assessment of second-generation bioethanol have been conducted. However, due to the different methodology used and different system boundary definition, it is difficult to compare their results. To permit a direct comparison of fuel ethanol from different lignocelluloses in terms of energy use and environmental impact, seven studies conducted in our group were summarized in this paper, where the same technologies were used to convert biomass to ethanol, the same system boundaries were defined, and the same allocation procedures were followed. A complete set of environmental impacts ranging from global warming potential to toxicity aspects is used. The results provide an overview on the energy efficiency and environmental performance of using fuel ethanol derived from different feedstocks in comparison with gasoline. 1. Introduction Climate change and the wish to reduce the dependence on oil are the incentives for the development of alternative energy sources. In view of the carbon dioxide reduction target agreed upon in the Kyoto protocol, a shift from fossil fuels to renewable resources is ongoing, also to secure the long-term energy supply at both national and international level. The European Commission demonstrated in 2007 that a 20% target for the overall share of energy from renewable sources and a 10% target for energy from renewable sources in transport would be appropriate and achievable objectives [1], though both targets have become subject of dispute since then. In the near term, liquid biofuels will still largely contribute to the target in transport sector due to the limited available technologies for fuels from other renewable sources. Especially bioethanol with its biorenewable nature, optimized production technology, and potential of greenhouse gas (GHG) mitigation already proved itself as an attractive alternative fuel. Most of the current practice only concerns first-generation ethanol from conventional crops like corn, wheat, sorghum, potato, sugarcane, sugar beet, and so forth. Criticism is expressed on the first-generation bioethanol with regard to land use requirement and competition with food and nature. These issues have become the driving forces for the technology innovation towards
The energetic potential of bioethanol in Hungary  [PDF]
Károly Lakatos,Andrea Handki
Acta Montanistica Slovaca , 2008,
Abstract: The basis of the bioethanol production is the agriculture, mostly the corn and wheat growing. With the analysis of their domesticharvest results, the process of the starch formation and the chemical-thermodynamical processes of the alcohol’s fermantation,we calculate the annual amount of the producible bioethanol on average and it’s energy. We determine the specific values of the CO2cycle. We examine the energetic possibilities of total substitution of the 2 billion litres of domestic petrol consumption with bioethanol.
Airtight storage of moist wheat grain improves bioethanol yields
Volkmar Passoth, Anna Eriksson, Mats Sandgren, Jerry St?hlberg, Kathleen Piens, Johan Schnürer
Biotechnology for Biofuels , 2009, DOI: 10.1186/1754-6834-2-16
Abstract: The ethanol yield from moist wheat was enhanced by 14% compared with the control obtained from traditionally (dry) stored grain. This enhancement was observed independently of whether or not P. anomala was added to the storage system, indicating that P. anomala does not impair ethanol fermentation. Starch and sugar analyses showed that during pre-treatment the starch of moist grain was better degraded by amylase treatment than that of the dry grain. Additional pre-treatment with cellulose and hemicellulose-degrading enzymes did not further increase the total ethanol yield. Sugar analysis after this pre-treatment showed an increased release of sugars not fermentable by Saccharomyces cerevisiae.The ethanol yield from wheat grain is increased by airtight storage of moist grain, which in addition can save substantial amounts of energy used for drying the grain. This provides a new opportunity to increase the sustainability of bioethanol production.In temperate climates, harvest of cereal grain must often be done at high moisture content as the vegetation period is rather short. This requires high amounts of energy for drying to enable safe storage of the harvested material and avoid mould growth. In Sweden, hot-air drying is often the process during grain production that consumes the highest proportion of input energy, that is, up to 60% [1]. With regard to biofuel production from cereal grains, there are concerns about the energy balance and sustainability of the currently established processes. A recent study showed that the net output of energy in bioethanol production was rather small when using corn as raw material [2]. Substantial improvements of the energy balance of a bioethanol production process can only be achieved by an optimisation of all the partial processes involved. In regions with a temperate climate, a reduction in energy demand for the storage of the raw material will have a large impact on the energy balance. Due to increasing energy prices, this wo
Progress in the production of bioethanol on starch-based feedstocks  [PDF]
Ljiljana Mojovi?,Du?anka Pejin,Olgica Gruji?,Sini?a Markov
Chemical Industry and Chemical Engineering Quarterly , 2009,
Abstract: Bioethanol produced from renewable biomass, such as sugar, starch, or lignocellulosic materials, is one of the alternative energy resources, which is both renewable and environmentally friendly. Although, the priority in global future ethanol production is put on lignocellulosic processing, which is considered as one of the most promising second-generation biofuel technologies, the utilizetion of lignocellulosic material for fuel ethanol is still under improvement. Sugar- based (molasses, sugar cane, sugar beet) and starch-based (corn, wheat, triticale, potato, rice, etc.) feedstock are still currently predominant at the industrial level and they are, so far, economically favorable compared to lingocelluloses. Currently, approx. 80 % of total world ethanol production is obtained from the fermentation of simple sugars by yeast. In Serbia, one of the most suitable and available agricultural raw material for the industrial ethanol production are cereals such as corn, wheat and triticale. In addition, surpluses of this feedstock are being produced in our country constantly. In this paper, a brief review of the state of the art in bioethanol production and biomass availability is given, pointing out the progress possibilities on starch-based production. The progress possibilities are discussed in the domain of feedstock choice and pretreatment, optimization of fermentation, process integration and utilization of the process byproducts.
Pretreatments of lignocellulosic feedstock for bioethanol production
Predojevi? Zlatica J.
Hemijska Industrija , 2010, DOI: 10.2298/hemind100217016p
Abstract: The use of renewable energy sources (biofuels), either as a component in the conventional fossil fuels, gasoline and diesel, or as a pure biofuel, contributes to energy saving and decrease of total CO2 emission. The use of bioethanol mixed with gasoline significantly decreases gasoline consumption and contributes to environment protection. One of the problems in the production of bioethanol is the availability of sugar and starch based feedstock used for its production. However, lignocellulosic feedstocks are becoming more significant in the production of bioethanol due to their availability and low cost. The aim of this study is to point out the advantages and shortcomings of pretreatment processes and hydrolyses of lignocellulosic feedstocks that precede their fermentation to bioethanol.
Energy Resources in the Future  [PDF]
Ken Tomabechi
Energies , 2010, DOI: 10.3390/en3040686
Abstract: Recent statistics indicate that in 2005 the world consumed about 0.5 ZJ (ZJ = 10 21 Joules) of energy. If one assumes that the future world population stabilizes at 10 billions, and the people consume a similar amount of energy per capita to that of the people in the presently developed countries, the world will need about 2 ZJ a year. A recent survey of the available future energy resources indicates that the energies recoverable from coal, oil and gas are only 23 ZJ, 6.7 ZJ and 6.4 ZJ, respectively. Other energy resources such as solar and wind have problems of fluctuation due to the weather conditions. However, the energy expected from known Uranium resources by breeder reactors is 227 ZJ and that from Lithium by fusion reactors is more than 175 ZJ. Therefore, it is important to make efforts to develop and use breeder reactors and fusion reactors to supply a major part of the energy need in the future.
Techno-economic evaluation of 2nd generation bioethanol production from sugar cane bagasse and leaves integrated with the sugar-based ethanol process
Stefano Macrelli, Johan Mogensen, Guido Zacchi
Biotechnology for Biofuels , 2012, DOI: 10.1186/1754-6834-5-22
Abstract: The addition of a steam dryer, doubling of the enzyme dosage in enzymatic hydrolysis, including leaves as raw material in the 2G process, heat integration and the use of more energy-efficient equipment led to a 37% reduction in MESP-2G compared to the Base case. Modelling showed that the MESP for 2G ethanol was 0.97 US$/L, while in the future it could be reduced to 0.78 US$/L. In this case the overall production cost of 1G + 2G ethanol would be about 0.40 US$/L with an output of 102 L/ton dry sugar cane including 50% leaves. Sensitivity analysis of the future scenario showed that a 50% decrease in the cost of enzymes, electricity or leaves would lower the MESP-2G by about 20%, 10% and 4.5%, respectively.According to the simulations, the production of 2G bioethanol from sugar cane bagasse and leaves in Brazil is already competitive (without subsidies) with 1G starch-based bioethanol production in Europe. Moreover 2G bioethanol could be produced at a lower cost if subsidies were used to compensate for the opportunity cost from the sale of excess electricity and if the cost of enzymes continues to fall.Currently in Brazil, the production of sugar cane bioethanol is based entirely on the fermentation of sugar juice from sugar cane and/or molasses in autonomous distilleries (39% of the cases) and in plants associated with sugar mills (61%) [1]. This technology has been in commercial use for the past 30 years and can be considered to be mature as the cost of feedstock accounts for a major part of the production cost [2], around 60-70% [3,4]. Compared to other crops used for bioethanol production from sugar and starch, i.e. first-generation (1G) bioethanol, bioethanol from sugar cane is claimed to have the lowest production cost worldwide [5]. The low cost of Brazilian 1G bioethanol can be explained by a combination of favourable conditions such as the photosynthetic rate of the sugar cane crop per hectare, the meteo-climatic conditions and a renewable energy ratio close t
Energy Resources in the Future
International Journal of Energy Engineering , 2012, DOI: 10.5923/j.ijee.20120204.02
Abstract: Recent statistics indicate that in 2009 the world consumed about 0.505 ZJ (ZJ = 1021 Joules) of energy. If one assumes optimistically that the future world population will be stabilized at 10 billions, and the people will consume a similar amount of energy per capita to that of the people in the presently developed countries, the world will need about 2 ZJ a year. A recent survey of the available future energy resources indicates that the energies recoverable from coal, oil and gas are only 22.4 ZJ, 6.7 ZJ and 6.4 ZJ respectively. Other energy resources such as solar and wind have problems of fluctuation due to the weather conditions. However, the energy expected from known Uranium resources by fast breeder reactors is 227 ZJ and that from Lithium by fusion reactors is more than 175 ZJ. Therefore, it is important to make efforts to develop and use fast breeder reactors and fusion reactors to supply a major part of energy need in the future.
On the Future High Energy Colliders  [PDF]
Vladimir Shiltsev
Physics , 2015,
Abstract: High energy particle colliders have been in the forefront of particle physics for more than three decades. At present the near term US, European and international strategies of the particle physics community are centered on full exploitation of the physics potential of the Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). A number of the next generation collider facilities have been proposed and are currently under consideration for the medium and far-future of accelerator-based high energy physics. In this paper we offer a uniform approach to evaluation of various accelerators based on the feasibility of their energy reach, performance potential and cost range.
Dark Energy Present and Future  [PDF]
Paul H. Frampton
Physics , 2003, DOI: 10.1063/1.1627737
Abstract: By studying the present cosmological data, particularly on CMB, SNeIA and LSS, we find that the future fate of the universe, for simple linear models of the dark energy equation-of-state, can vary between the extremes of (I) a divergence of the scale factor in as little as 7 Gyr; (II) an infinite lifetime of the universe with dark energy dominant for all future time; (III) a disappearing dark energy where the universe asymptotes as $t \to \infty$ to $a(t) \sim t^{2/3}$ {\it i.e.} matter domination. Precision cosmological data hint that a dark energy with equation of state $w = P/\rho < -1$ and hence dubious stability is viable. Here we discuss for any $w$ nucleation from $\Lambda > 0$ to $\Lambda = 0$ in a first-order phase transition. The critical radius is argued to be at least of galactic size and the corresponding nucleation rate glacial, thus underwriting the dark energy's stability and rendering remote any microscopic effect.
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