Dissertations / Theses on the topic 'Biofuel (Biomass) Energy'
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1
Thondhlana, Gladman. "Land acquisition for and local livelihood implications of biofuel development in Zimbabwe." Rhodes University, 2016. http://hdl.handle.net/10962/49940.
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In recent years, proponents of 'green and clean fuel' have argued that the costs of overreliance on fossil fuels could be reduced through transition to biofuels such as bio-ethanol. Global biofuel discourses suggest that any transition to biofuel invariably results in significant benefits, including energy independence, job creation, development of agro-industrial centres at local level and high revenue generations for the state with minimum negative impacts on the environment. With many risks and costs associated with traditional 'dirty' fuels, it is likely that many countries, particularly African countries, will move towards the 'green and clean fuel' alternative. However, until recently research has arguably paid limited attention to the local livelihood impacts related to land acquisition for biofuel development or the policy frameworks required to maximise biofuel benefits. With regards to biofuel benefits, some recent studies suggest that the much bandied potential for greater tax revenue, lowered fuel costs and wealth distribution from biofuel production have all been perverted with relatively little payoff in wage labour opportunities in return (e.g. Richardson, 2010; Wilkinson and Herrera, 2010). Based on work done in Chisumbanje communal lands of Zimbabwe (Thondhlana, 2015), this policy brief highlights the local livelihood impacts of biofuel development and discusses policy implications of the findings. By highlighting the justifications of biofuel development at any cost by the state, the study sheds some light on the conflicts between state interests and local livelihood needs.
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Anfinrud, Robynn Elizabeth. "Nitrogen Uptake and Biomass and Ethanol Yield of Biomass Crops as Feedstock for Biofuel." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26524.
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Nitrogen fertilizers are extensively used to enhance the growth of biomass crops. This study was conducted to determine the effect of N rates on the biomass yield and quality, and N uptake of several crops. The experiment was conducted at Fargo and Prosper, ND, in 2010 and 2011. The crops studied were forage sweet sorghum [Sorghum bicolor L. Moench], sorghum x sudangrass [Sorghum bicolor var. sudanense (Piper) Stapf.], kenaf [Hibiscus cannabinus L.], and reed canarygrass [Phalaris arundinacea L.]. The different crops constituted the main plots and the nitrogen rates were regarded as subplots. The five N rates were 0, 75, 100, 150, and 200 kg N ha-1.
Forage sweet sorghum and sorghum x sudangrass had the greatest dry matter biomass yield. Nitrogen fertilization increased biomass yield for each of the crops. The results indicate that forage sorghum and sorghum x sudangrass have the greatest potential as a feedstock.
3
Inglesby, Alister Edward. "Biochemical and bioelectrochemical technology for third generation biofuel production." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648335.
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Adebayo, Adebola B. "Pretreatments and energy potentials of Appalachian hardwood residues for biofuel production." Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/10928.
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Thesis (Ph. D.)--West Virginia University, 2010.Title from document title page. Document formatted into pages; contains viii, 98 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references.
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Kazamia, Elena. "Synthetic ecology : a way forward for sustainable algal biofuel production." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607904.
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Adesanya, Victoria Oluwatosin. "Investigation into the sustainability and feasibility of potential algal-based biofuel production." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708126.
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Matakala, Litiya. "Biofuel policies : what can Zambia learn from leading biofuel producers." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/5748.
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Thesis (MDF (Development Finance))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: Price volatility and high dependency on imported petroleum fuel has prompted the Zambian government to look into renewable fuels as part of an energy diversification program. With growing global interest in biofuels as a transportation fuel, the Zambian government intends to introduce bioethanol and biodiesel as renewable fuels in the transportation sector. While it seems feasible to produce both the feedstocks and biofuels to meet local demand, a regulatory framework and industry support mechanisms have not yet been formulated. The policy and regulatory frameworks encompass a multitude of actors, networks and institutions all playing distinct and important roles. Incorporating the differing interests of all these stakeholders is an involving process that requires detailed analysis of agriculture, environmental, energy, socioeconomic and taxation policies. This study attempts to contribute to the biofuels policy formulation process in Zambia. It analyses biofuel policies in leading biofuels producing countries and identifies aspects that the Zambian government should consider incorporating in its own policies to ensure a viable biofuels industry. Biofuel policies in Brazil, Germany and the United States of America were analysed using a detailed case study and extensive literature review. Furthermore, a detailed analysis of the Zambian agriculture sector and the demand for petroleum fuel puts into context the potential demand and challenges likely to be faced. By understanding the history and development of biofuels in the case study countries, best practices, problems faced, policy innovations and industry support mechanisms were identified to inform policy formulation in Zambia. This does not only provide valuable insights and lessons but also ensures that time and resources are not wasted by reinventing the wheel. The comparative analysis of policies and support mechanisms in the three case study countries showed that articulating a clear policy objective, government support in the form of subsidies, wide stakeholder involvement and industry regulation have all played a critical role in the development of the industry. However, the extent to which all these factors have helped to shape the industry in Brazil, Germany and the USA is neither equal nor static. Countries are continuously adapting their policies and support mechanisms to environmental, energy and economic conditions.
AFRIKAANSE OPSOMMING: Die onbestendigheid van pryse en die groot mate van afhanklikheid van ingevoerde petroleumbrandstof het die Zambiese regering aangespoor om ondersoek in te stel na hernubare brandstof as deel van 'n energiediversifiseringsprogram. In die lig van die groeiende globale belangstelling in biobrandstof as vervoerbrandstof, beplan die Zambiese regering om bioetanol en biodiesel as hernubare brandstof in die vervoersektor te begin gebruik. Al lyk dit prakties uitvoerbaar om sowel die voerstof as die biobrandstof te vervaardig om in die plaaslike aanvraag te voorsien, is 'n reguleringsraamwerk en ondersteuningsmeganismes vir die industrie nog nie geskep nie. 'n Menigte rolspelers, netwerke en instellings, wat almal verskillende en belangrike rolle speel, sal betrokke wees by die beleidsformulering en reguleringsraamwerk. Om die uiteenlopende belange van al die betrokke partye in ag te neem is 'n ingewikkelde proses wat sal vereis dat 'n uitvoerige analise gemaak word van landbou-, omgewings-, energie-, sosio-ekonomiese en belastingbeleidsrigtings. Die doelwit van hierdie studie is om 'n bydrae te lewer tot die formuleringsproses van die biobrandstofbeleid in Zambie. Dit analiseer die biobrandstofbeleid van die vooraanstaande lande wat biobrandstof vervaardig, en identifiseer aspekte wat die Zambiese regering in sy beleid behoort in te sluit om 'n lewensvatbare biobrandstofindustrie te verseker. Die biobrandstofbeleid van Brasilie, Duitsland en die Verenigde State van Amerika (VSA) is geanaliseer met behulp van uitvoerige gevallestudies en 'n grondige literatuurstudie. Verder plaas 'n noukeurige analise van die Zambiese landbousektor en die aanvraag na petroleumbrandstof die potensiele aanvraag en uitdagings wat waarskynlik hanteer sal meet word in konteks. Deur insig te verkry in die geskiedenis en ontwikkeling van biobrandstof in die lande waar die gevallestudies gedoen is, kon die beste gebruike, moontlike probleme, nuwe beleidsrigtings en ondersteuningsmeganismes in die bedryf geidentifiseer word om die beleid in Zambie te help formuleer. Dit bied nie slegs waardevolle insig en leergeleenthede nie, maar verseker ook dat tyd en hulpbronne nie vermors word deur die wiel van voor af uit te vind nie. Die vergelykende analise van die beleidsrigtings en ondersteuningsmeganismes in die drie lande waar die gevallestudies gedoen is, het getoon dat 'n duidelik geformuleerde beleidsdoelwit, ondersteuning van die regering in die vorm van subsidies, die algemene betrokkenheid van belanghebbendes en die regulering van die industrie alles 'n uiters belangrike rol gespeel het in die ontwikkeling van hierdie industrie. Die mate waarin al hierdie faktore die industrie in Brasilie, Duitsland en die VSA help vorm het, het egter gewissel en was nooit staties nie. Lande pas voortdurend hulle beleid en ondersteuningsmeganismes aan by omgewings-, energie- en ekonomiese toestande.
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Görling, Martin. "Turbomachinery in Biofuel Production." Licentiate thesis, KTH, Energiprocesser, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-28901.
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The aim for this study has been to evaluate the integration potential of turbo-machinery into the production processes of biofuels. The focus has been on bio-fuel produced via biomass gasification; mainly methanol and synthetic natural gas. The research has been divided into two parts; gas and steam turbine applications. Steam power generation has a given role within the fuel production process due to the large amounts of excess chemical reaction heat. However, large amounts of the steam produced are used within the production process and is thus not available for power production. Therefore, this study has been focused on lowering the steam demand in the production process, in order to increase the power production. One possibility that has been evaluated is humidification of the gasification agent in order to lower the demand for high quality steam in the gasifier and replace it with waste heat. The results show that the power penalty for the gasification process could be lowered by 18-25%, in the specific cases that have been studied. Another step in the process that requires a significant amount of steam is the CO2-removal. This step can be avoided by adding hydrogen in order to convert all carbon into biofuel. This is also a way to store hydrogen (e.g. from wind energy) together with green carbon. The results imply that a larger amount of sustainable fuels can be produced from the same quantity of biomass. The applications for gas turbines within the biofuel production process are less obvious. There are large differences between the bio-syngas and natural gas in energy content and combustion properties which are technical problems when using high efficient modern gas turbines. This study therefore proposes the integration of a natural gas fired gas turbine; a hybrid plant. The heat from the fuel production and the heat recovery from the gas turbine flue gas are used in a joint steam cycle. Simulations of the hybrid cycle in methanol production have shown good improvements. The total electrical efficiency is increased by 1.4-2.4 percentage points, depending on the fuel mix. The electrical efficiency for the natural gas used in the hybrid plant is 56-58%, which is in the same range as in large-scale combined cycle plants. A bio-methanol plant with a hybrid power cycle is consequently a competitive production route for both biomass and natural gas.QC 20110128
9
Luo, Dexin. "Design of highly distributed biofuel production systems." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45878.
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This thesis develops quantitative methods for evaluation and design of large-scale biofuel production systems with a particular focus on bioreactor-based fuel systems. In Chapter 2, a lifecycle assessment (LCA) method is integrated with chemical process modeling to select from different process designs the one that maximizes the energy efficiency and minimizes the environmental impact of a production system. An algae-based ethanol production technology, which is in the process of commercialization, is used as a case study. Motivated by this case study, Chapter 3 studies the selection of process designs and production capacity of highly distributed bioreactor-based fuel system from an economic perspective. Nonlinear optimization models based on net present value maximization are developed that aim at selecting the optimal capacities of production equipment for both integrated and distributed-centralized process designs on symmetric production layouts. Global sensitivity analysis based on Monte Carlo estimates is performed to show the impact of different parameters on the optimal capacity decision and the corresponding net present value. Conditional Value at Risk optimization is used to compare the optimal capacity for a risk-neutral planner versus a risk-averse decision maker. Chapter 4 studies mobile distributed processing in biofuel industry as vehicle routing problem and production equipment location with an underlying pipeline network as facility location problem with a focus on general production costs. Formulations and algorithms are developed to explore how fixed cost and concavity in the production cost increases the theoretical complexity of these problems.
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Guo, Zhimei. "Economic and policy perspectives of biofuel as an emerging use of forest biomass in Mississippi." Master's thesis, Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-09072007-125135.
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Orr, Kyla Kathleen. "Predicting the ecosystem effects of harvesting beach-cast kelp for biofuel." Thesis, University of the Highlands and Islands, 2013. https://pure.uhi.ac.uk/portal/en/studentthesis/predicting-the-ecosystem-effects-of-harvesting-beachcast-kelp-for-biofuel(82d8913a-164a-4e21-b61b-9f83b462b079).html.
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Beach‐cast kelp (principally Laminaria spp.), known as macroalgal wrack, has been suggested as a feedstock for biofuel. However, to be extracted sustainably it is necessary to understand its ecological role and predict the impacts of its removal. Field‐based observations combined with food web modelling were used to predict the ecosystem effects of removing wrack from beaches of the Uists, western Scotland. Beaches with wrack were associated with enriched benthic infauna (polychaetes) on the lower shore, and wrack mounds supported abundant macroinvertebrates (mainly Diptera larvae and oligochaetes); with some of the highest biomasses reported globally for beaches. These fauna are valuable prey to shorebirds, as demonstrated by a strong positive relationship (R2 = 0.82) between wader abundances and the percentage cover of wrack on beaches. Inshore, drifting macroalgae was associated with elevated abundances of detritivorous hyperbenthic fauna (mysids, isopods and gammarid amphipods). In addition, the volume of drifting macroalgae inshore was a significant predictor (along with physical beach characteristics) for the abundance of decapods and fish. Food web models and network analysis indicated that beaches which accumulate wrack had a greater diversity of trophic links and more functional redundancy, making their food webs more resilient to perturbations. Such perturbations may include stressors induced by climate change, such as increased erosion of sediments during storms, elevated atmospheric and sea surface temperatures and elevated CO2 concentrations. Model simulations of wrack harvesting predicted an immediate decline in primary consumers in direct proportion to the quantity of wrack removed, and a slow decline in shorebirds in response to reduced prey. Primary consumers were predicted to recover to their pre‐harvest biomasses within 1 to 2 years regardless of harvesting intensity, but recovery times for shorebirds were an order of magnitude longer, and increased with harvesting intensity. Harvesting more than 50% wrack predicted a ‘collapse’ in wader populations within 25 years, and recovery times of 45‐60 years were estimated if >70% wrack was removed. The findings of this thesis suggest wrack provides essential food and shelter to coastal fauna, and its large‐scale removal would have significant negative impacts to the ecosystem functioning.
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Fischback, Michael Bryant. "Introduction and characterization of an innovative biofuel cell platform with improved stability through novel enzyme immobilization techniques." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/m_fischback_121206.pdf.
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Wong, Ka In. "Machine-learning-based modeling of biofuel engine systems with applications to optimization and control of engine performance." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691886.
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Chan, Jin Hooi. "Evolution of biofuel value chain governance and government policy : the cases of China, Thailand, the Philippines and Vietnam." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610635.
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Berger, Elena M. "Dynamics of innovation of biofuel ethanol. three decades of experience in the U.S. and in Brazil." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37315.
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This dissertation draws on the burgeoning field of innovation of low carbon technologies. Using the functions of innovation systems, this study explores the process of innovation of biofuel ethanol in the U.S. and in Brazil. It uses "process theory" to build a narrative of historical events that represent the innovation trajectory of ethanol biofuel in the U.S. and in Brazil over a period of thirty years. The data is drawn from newspaper articles from the New York Times, Washington Post, and O Estado de Sao Paulo published between 1975 and 2008. Results of this research confirm findings published previously that innovation performs better when the main actors in the innovation process act under clear and well defined policy targets, and when the innovation environment contributes to building positive expectations about the technology. The empirical findings build upon the literature and validate early claims that the alignment of goals between technology producers and users is an inducer of innovation. Moreover, the analysis presented shows that by developing new capabilities, technology users in the downstream market broaden the innovation environment and facilitate the adoption of the emerging technology by new users and markets. For example, the automobile sector has been participating actively in the ethanol technological innovation system in Brazil, facilitating the innovation flow between upstream and the downstream market. This has not been the case in the U.S., where the automobile sector has not found incentives to participate in the ethanol technological innovation systems.
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Ndimande, Sandile. "Increasing cellulosic biomass in sugarcane." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86296.
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Thesis (PhD)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Increased demand of petroleum, declining fossil fuel reserves, geopolitical instability and the environmentally detrimental effects of fossil fuels have stimulated research to search for alternative sources of energy such as plant derived biofuels. The main feedstocks for production of first generation biofuels (bioethanol) are currently sucrose and starch, produced by crops such as sugarcane, sugarbeet, maize, and cassava. The use of food crop carbohydrates to produce biofuels is viewed as competing for limited agronomic resources and jeopardizing food security. Plants are also capable of storing sugars in their cell walls in the form of polysaccharides such as cellulose, hemicelluloses and pectin, however those are usually cross-linked with lignin, making their fermentation problematic, and are consequently referred to as lignocellulosics. Current technologies are not sufficient to degrade these cell wall sugars without large energy inputs, therefore making lignocellulosic biomass commercially unviable as a source of sugars for biofuel production. In the present study genes encoding for enzymes for cellulosic, hemicellulosic and starch-like polysaccharides biosynthesis were heterologously expressed to increase the amount of fermentable sugars in sugarcane. Transgenic lines heterologously expressing CsCesA, encoding a cellulose synthase from the marine invertebrate Ciona savignyi showed significant increases in their total cellulose synthase enzyme activity as well as the total cellulose content in internodal tissues. Elevation in cellulose contents was accompanied by a rise in hemicellulosic glucose content and uronic acid amounts, while total lignin was reduced in internodal tissues. Enzymatic saccharification of untreated lignocellulosic biomass of transgenic sugarcane lines had improved glucose release when exposed to cellulose hydrolyzing enzymes. Calli derived from transgenic sugarcane lines ectopically expressing galactomannan biosynthetic sequences ManS and GMGT from the cluster bean (Cyamopsis tetragonoloba) were observed to be capable of producing a galactomannan polysaccharide. However, after regeneration, transgenic sugarcane plants derived from those calli were unable to produce the polymer although the inserted genes were transcribed at the mRNA level. While the ectopic expression of Deinococcus radiodurans amylosucrase protein in the cytosol had a detrimental effect on the growth of transgenic lines (plants showed stunted growth through the 18 months growth period in greenhouse), contrastingly targeting the amylosucrase protein into the vacuole resulted in 3 months old transgenic lines which were having high maltooligosaccharide and soluble sugar (sucrose, glucose and fructose) levels in leaves. After 18 months growing in the greenhouse, the mature transgenic lines were morphologically similar to the untransformed lines and also contained comparable maltooligosaccharide and soluble sugar and starch amounts. The non-biosynthesis of galactomannan and amylose polysaccharides in the matured transgenic plants may be due to post-transcriptional protein processing and or protein instability, possibly explainable by other epigenetic mechanisms taking place to regulate gene expression in the at least allo-octaploid species of sugarcane under investigation in this study.
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Von, Maltitz Graham Paul. "Biofuel, land-use tradeoffs and livelihoods in Southern Africa." Thesis, Nelson Mandela Metropolitan University, 2014. http://hdl.handle.net/10948/d1021005.
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The rapid expansion of biofuel projects in southern Africa creates an opportune issue against which to examine land-use tradeoffs within the areas of customary land tenure. For this an ecosystems services approach is used. Jatropha curcas (L), a perennial oilseed plant which has been the key focus of most of the region’s biofuel expansion to date is used as the focus biofuel crop for which case study data were obtained from Malawi, Mozambique, Zambia and South Africa. Despite the initial enthusiasm for jatropha, most projects have proven less successful than hoped, and many have collapsed. A few are, however, still showing signs of possible success and it is two of these that form the basis of the case studies. Hugely complex tradeoffs are involved when considering biofuel as a land-use option for communal areas. They range from global impacts such as biodiversity and global climate forcing, through national concerns of rural development, national food security and national fuel security, to local household concerns around improving livelihoods. Land that is converted to biofuel needs to be removed from some previous use, and in the southern African case it is typically woodlands and the multitude of services they provide, that suffer. The nature of the tradeoffs and the people affected change over the scale under consideration. For the local farmer it is only the local issues that are of concern, but national and global forces will change the policy environment and lead to new types of development such as biofuels. Change is inevitable, and in all developments there are likely to be both winners and losers. It is clear that the impacts arising from biofuel are situation dependent, and each community and location has unique social and environmental considerations that need to be taken into account. In the case of jatropha the final realised yield and the economic returns that this can generate, will be of critical importance and remain one of the main uncertainties. There are promising signs that under certain circumstances the balance of benefits from jatropha biofuel may be positive, but if implemented incorrectly or in the wrong place, there is extensive evidence of total project failure. It is clear that evidence-based data and assessment tools are needed to assist communities, developers and government departments to make sound decisions around biofuel (or other land-use based) development. A number of such tools are suggested in the thesis. Both the use of large-scale plantations or small-scale farmer centred projects have their advantages and disadvantages. It is probable that in the correct circumstances either can work. However, large-scale plantations can have huge negative social and environmental consequences if poorly implemented. Small-scale projects, though improving livelihoods, are unlikely to take the farmers out of poverty. Tradeoffs from any land-use change are inevitable. Empirical data on biofuel impacts on the environment and society are needed for the development of sound policy. A favourable policy environment can ensure that positive benefits from biofuel are obtained, whilst minimising negative impacts. To develop this policy means that southern African countries will have to clearly understand what they wish to achieve from biofuel, as well as having a clear understanding of impacts from biofuel implementation. Sound scientific knowledge needs to underpin this process. For instance governments may wish to increase the ratio of small-scale to large-scale plantation to increase the developmental benefits, ensure biofuel is used to promote national fuel security rather than being exported, or develop a medium-scale farming sector which can help move farmers out of poverty and assist in developing a market surplus of agricultural commodities. Analysing impacts from biofuel expansion is a complex and multi-dimensional problem and as such will require multi-criteria analysis tools to develop solutions. Global, national and local tradeoffs must all be considered. In addition a wide range of stakeholders are involved and participatory processes may be needed to capture their inputs. Tools to better analyse impacts, specifically at the local level are needed. These local results need to feed into national level economic assessments. The cost of biofuel introduction should be considered against the costs of not implementing biofuel, realising that doing nothing also has a cost and long-term impact. Third-party certification provides a useful tool for shifting costs of ensuring compliance with social and environmental legislation, from the state to biofuel companies. In addition ongoing monitoring and evaluation of existing projects is needed to learn from successes and failures, to identify unintended consequences, and to increase the resilience of projects, community livelihoods and the national economy. This will have to be supplemented with additional focused and ongoing research.
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Nguyen, Thi Hong Minh, and Van Hanh Vu. "Bioethanol production from marine algae biomass: prospect and troubles." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-99282.
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The increase of petroleum cost as well as global warming and climate change result in investigation to discover new renewable energy resources. Bioenergy is one of the most important sources that is concerning the scientists and industrial sector. Although bioethanol had to be known as one of the most important renewable energy sources in order to reduce greenhouse gases and global warming, there is a limited number of publications reporting on them. In this review, a brief overview is offered about bioethanol production from algae. It can be given a deeper insight in dificulties and promising potential of bioethanol from algaeSự gia tăng giá nhiên liệu hóa thạch cùng với cảnh báo toàn cầu về biến đổi khí hậu hướng đến việc nghiên cứu tìm ra những nguồn năng lượng có thể tái tạo. Năng lượng sinh học là một trong những nguồn quan trọng được các nhà khoa học và doanh nghiệp quan tâm. Mặc dù ethanol sinh học đã được biết đến như là một trong những dạng năng lượng tái tạo quan trọng nhất để giảm thiểu các khí nhà kính và cảnh báo toàn cầu, nhưng chỉ có một số ít bài báo về nó. Trong bài tổng quan này, chúng tôi giới thiệu vắn tắt việc sản xuất ethanol sinh học từ tảo. Nó đưa ra cái nhìn sâu hơn về những khó khăn và tiềm năng hứa hẹn của sản xuất ethanol sinh học từ tảo
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Malta, Nuno Vital Serrador. "Plano de negócios - "Bio Wood Energy"." Master's thesis, Universidade de Évora, 2011. http://hdl.handle.net/10174/15208.
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Este projecto consiste na realização de um Plano de Negócios para criação de
uma empresa a laborar no ramo das madeiras.
Esta empresa, de tratamento de biomassa, será concebida com alguns objectivos
fundamentais como: produzir, consumir e comercializar energias “limpas” e ecológicas;
ter o máximo de autonomia possível; aproveitar ao máximo os recursos disponíveis,
dando o melhor uso possível aos produtos recebidos e produzidos; e, contribuir para um
aumento do número de postos de trabalho e desenvolvimento da zona onde irá ser
instalada.
Os produtos finais a comercializar serão: estilha calibrada; combustível sólido
(cascas, ramas, cepos e desbastes); e, biocombustivel refinado (pellets) e estilha
calibrada.
A empresa irá, também, produzir energia, através da minigeração de energia a
partir de painéis fotovoltaicos, de forma ter o máximo de auto-suficiência, e dessa forma
ser mais “amiga” do ambiente e conseguir redução de despesas.
O projecto demonstra ter grande probabilidade de sucesso, pois apresenta
elevada viabilidade económico-financeira; ABSTRACT: This project consist of a business plan for starting a woods business.
This company, of biomass processing, will be designed with some fundamental
objectives such as: producing, consuming and transact "clean" energy and
environmentally friendly; have as much autonomy as possible; make the most of
available resources, making the best use of the received and produced products; and
contribute to an increase in the number of jobs and development within the area where it
will be installed.
The transacted final products will be: chips calibrated, solid fuel (bark, branches,
stumps and thinning), and refined biofuels (pellets) and calibrated chips.
The company will also produce energy through microgeneration from
photovoltaic panels in order to have as much self-sufficiency as possible, and thus be
more "friendly" of the environment and also reduce expenses.
This project demonstrates a high probability of success, because it has high
economic and financial viability.
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Hu, Zhoujian. "Utilization of switchgrass as a biofuel feedstock." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44088.
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Secondary generation biofuels such as cellulosic biofuels rely on large portions of cellulosic bioresources, which may include forests, perennial grasses, wood and agricultural residues. Switchgrass is one promising feedstock for biofuel production. In the present study, thesis work focused on the chemical and structural profiles and hydrothermal pretreatment of switchgrass. Four populations of switchgrass were investigated for their chemical properties among populations and morphological portions, including the compositions of lignin and carbohydrates, extractives content, higher heating value (HHV), and syringyl:guaiacyl (S:G) ratio. The results demonstrate similar chemical profiles and lignin structure among the four populations of switchgrass. Morphological fractions of switchgrass including leaves, internodes, and nodes differ significantly in chemical profiles and S:G ratios of lignin. The structure of isolated cellulose from switchgrass SW9 is similar between leaves and internodes. The structure of isolated lignin from leaves and internodes of switchgrass SW9 differs in S:G ratio and molecular weight. Hydrothermal pretreatment of leaves and internodes indicates that a similar chemical composition and chemical structure for pretreated leaves and internodes. The degree of polymerization (DP) for cellulose of the pretreated internodes is 23.4% greater than that of the pretreated leaves. The accessibility of pretreated leaves measured by Simons' Staining technique is greater than that of pretreated internodes. Pretreated leaves have a 32.5-33.8% greater cellulose-to-glucose conversion yield than do pretreated internodes.
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Archbold, Brad. "Using algae to capture CO₂ and as a feedstock for biofuel." Online pdf file accessible through the World Wide Web, 2007. http://archives.evergreen.edu/masterstheses/Accession86-10MES/Archbold_%20B%20MESThesis%202007.pdf.
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Bojler, Görling Martin. "Energy system evaluation of thermo-chemical biofuel production : Process development by integration of power cycles and sustainable electricity." Doctoral thesis, KTH, Energiprocesser, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105814.
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Fossil fuels dominate the world energy supply today and the transport sector is no exception. Renewable alternatives must therefore be introduced to replace fossil fuels and their emissions, without sacrificing our standard of living. There is a good potential for biofuels but process improvements are essential, to ensure efficient use of a limited amount of biomass and better compete with fossil alternatives. The general aim of this research is therefore to investigate how to improve efficiency in biofuel production by process development and co-generation of heat and electricity. The work has been divided into three parts; power cycles in biofuel production, methane production via pyrolysis and biofuels from renewable electricity. The studies of bio-based methanol plants showed that steam power generation has a key role in the large-scale biofuel production process. However, a large portion of the steam from the recovered reaction heat is needed in the fuel production process. One measure to increase steam power generation, evaluated in this thesis, is to lower the steam demand by humidification of the gasification agent. Pinch analysis indicated synergies from gas turbine integration and our studies concluded that the electrical efficiency for natural gas fired gas turbines amounts to 56-58%, in the same range as for large combined cycle plants. The use of the off-gas from the biofuel production is also a potential integration option but difficult for modern high-efficient gas turbines. Furthermore, gasification with oxygen and extensive syngas cleaning might be too energy-consuming for efficient power generation. Methane production via pyrolysis showed improved efficiency compared with the competing route via gasification. The total biomass to methane efficiency, including additional biomass to fulfil the power demand, was calculated to 73-74%. The process benefits from lower thermal losses and less reaction heat when syngas is avoided as an intermediate step and can handle high-alkali fuels such as annual crops. Several synergies were discovered when integrating conventional biofuel production with addition of hydrogen. Introducing hydrogen would also greatly increase the biofuel production potential for regions with limited biomass resources. It was also concluded that methane produced from electrolysis of water could be economically feasible if the product was priced in parity with petrol.QC 20121127
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Danje, Stephen. "Fast pyrolysis of corn residues for energy production." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17822.
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Thesis (MScEng)--Stellenbosch University, 2011.ENGLISH ABSTRACT: Increasing oil prices along with the climate change threat have forced governments, society and the energy sector to consider alternative fuels. Biofuel presents itself as a suitable replacement and has received much attention over recent years. Thermochemical conversion processes such as pyrolysis is a topic of interest for conversion of cheap agricultural wastes into clean energy and valuable products. Fast pyrolysis of biomass is one of the promising technologies for converting biomass into liquid fuels and regarded as a promising feedstock to replace petroleum fuels. Corn residues, corn cob and corn stover, are some of the largest agricultural waste types in South Africa amounting to 8 900 thousand metric tonnes annually (1.7% of world corn production) (Nation Master, 2005). This study looked at the pyrolysis kinetics, the characterisation and quality of by-products from fast pyrolysis of the corn residues and the upgrading of bio-oil. The first objective was to characterise the physical and chemical properties of corn residues in order to determine the suitability of these feedstocks for pyrolytic purposes. Secondly, a study was carried out to obtain the reaction kinetic information and to characterise the behaviour of corn residues during thermal decomposition. The knowledge of biomass pyrolysis kinetics is of importance in the design and optimisation of pyrolytic reactors. Fast pyrolysis experiments were carried out in 2 different reactors: a Lurgi twin screw reactor and a bubbling fluidised bed reactor. The product yields and quality were compared for different types of reactors and biomasses. Finally, a preliminary study on the upgrading of bio-oil to remove the excess water and organics inorder to improve the quality of this liquid fuel was performed. Corn residues biomass are potential thermochemical feedstocks, with the following properties (carbon 50.2 wt. %, hydrogen 5.9 wt. % and Higher heating value 19.14 MJ/kg) for corn cob and (carbon 48.9 wt. %, hydrogen 6.01 wt. % and Higher heating value 18.06 MJ/kg) for corn stover. Corn cobs and corn stover contained very low amounts of nitrogen (0.41-0.57 wt. %) and sulphur (0.03-0.05 wt. %) compared with coal (nitrogen 0.8-1.9 wt. % and sulphur 0.7-1.2 wt. %), making them emit less sulphur oxides than when burning fossil fuels. The corn residues showed three distinct stages in the thermal decomposition process, with peak temperature of pyrolysis shifting to a higher value as the heating rate increased. The activation energies (E) for corn residues, obtained by the application of an iso-conversional method from thermogravimetric tests were in the range of 220 to 270 kJ/mol. The products obtained from fast pyrolysis of corn residues were bio-oil, biochar, water and gas. Higher bio-oil yields were produced from fast pyrolysis of corn residues in a bubbling fluidised bed reactor (47.8 to 51.2 wt. %, dry ash-free) than in a Lurgi twin screw reactor (35.5 to 37 wt. %, dry ash-free). Corn cobs produced higher bio-oil yields than corn stover in both types of reactors. At the optimised operating temperature of 500-530 °C, higher biochar yields were obtained from corn stover than corn cobs in both types of reactors. There were no major differences in the chemical and physical properties of bio-oil produced from the two types of reactors. The biochar properties showed some variation in heating values, carbon content and ash content for the different biomasses. The fast pyrolysis of corn residues produced energy products, bio-oil (Higher heating value = 18.7-25.3 MJ/kg) and biochar (Higher heating value = 19.8-29.3 MJ/kg) comparable with coal (Higher heating value = 16.2-25.9 MJ/kg). The bio-oils produced had some undesirable properties for its application such as acidic (pH 3.8 to 4.3) and high water content (21.3 to 30.5 wt. %). The bio-oil upgrading method (evaporation) increased the heating value and viscosity by removal of light hydrocarbons and water. The corn residues biochar produced had a BET Brynauer-Emmet-Teller (BET) surface area of 96.7 to 158.8 m2/g making it suitable for upgrading for the manufacture of adsorbents. The gas products from fast pyrolysis were analysed by gas chromatography (GC) as CO2, CO, H2, CH4, C2H4, C2H6, C3H8 and C5+ hydrocarbons. The gases had CO2 and CO of more than 80% (v/V) and low heating values (8.82-8.86 MJ/kg).
AFRIKAANSE OPSOMMING: Die styging in olie pryse asook dreigende klimaatsveranderinge het daartoe gelei dat regerings, die samelewing asook die energie sektor alternatiewe energiebronne oorweeg. Biobrandstof as alternatiewe energiebron het in die afgope paar jaar redelik aftrek gekry. Termochemiese omskakelingsprosesse soos pirolise word oorweeg vir die omskakeling van goedkoop landbou afval na groen energie en waardevolle produkte. Snel piroliese van biomassa is een van die mees belowende tegnologië vir die omskakeling van biomassa na vloeibare brandstof en word tans gereken as ’n belowende kandidaat om petroleum brandstof te vervang. Mielieafval, stronke en strooi vorm ’n reuse deel van die Suid Afrikaanse landbou afval. Ongeveer 8900 duisend metrieke ton afval word jaarliks geproduseer wat optel na ongeveer 1.7% van die wêreld se mielie produksie uitmaak (Nation Master, 2005). Hierdie studie het gekk na die kinetika van piroliese, die karakterisering en kwaliteit van by-produkte van snel piroliese afkomstig van mielie-afval asook die opgradering van biobrandstof. Die eerste mikpunt was om die fisiese en chemiese karakteristieke van mielie-afval te bepaal om sodoende die geskiktheid van hierdie afval vir die gebruik tydens piroliese te bepaal. Tweendens is ’n kinetiese studie onderneem om reaksie parameters te bepaal asook die gedrag tydens termiese ontbinding waar te neem. Kennis van die piroliese kinetika van biomassa is van belang juis tydens die ontwerp en optimering van piroliese reaktore. Snel piroliese ekspermente is uitgevoer met behulp van twee verskillende reaktore: ’n Lurgi twee skroef reaktor en ’n borrelende gefluidiseerde-bed reaktor. Die produk opbrengs en kwaliteit is vergelyk. Eindelik is ’n voorlopige studie oor die opgradering van bio-olie uitgevoer deur te kyk na die verwydering van oortollige water en organiese materiaal om die kwaliteit van hierdie vloeibare brandstof te verbeter. Biomassa afkomstig van mielie-afval is ’n potensiële termochemiese voerbron met die volgende kenmerke: mielie stronke- (C - 50.21 massa %, H – 5.9 massa %, HHV – 19.14 MJ/kg); mielie strooi – (C – 48.9 massa %, H – 6.01 massa %, HHV – 18.06 MJ/kg). Beide van hierdie materiale bevat lae hoeveelhede N (0.41-0.57 massa %) and S (0.03-0.05 massa %) in vergelyking met steenkool N (0.8-1.9 massa %) and S (0.7-1.2 massa %). Dit beteken dat hieride bronne van biomassa laer konsentrasies van swael oksiedes vrystel in vergelyking met fossielbrandstowwe. Drie kenmerkende stadia is waargeneem tydens die termiese afbraak van mielie-afval, met die temperatuur piek van piroliese wat skuif na ’n hoër temperatuur soos die verhittingswaarde toeneem. Die waargenome aktiveringsenergie (E) van mielie-afval bereken met behulp van die iso-omskakelings metode van TGA toetse was in die bestek: 220 tot 270 kJ/mol. Die produkte verkry deur Snel Piroliese van mielie-afval was bio-olie, bio-kool en gas. ’n Hoër opbrengs van bio-olie is behaal tydens Snel Piroliese van mielie-afval in die borrelende gefluidiseerde-bed reakctor (47.8 na 51.2 massa %, droog as-vry) in vergelyking met die Lurgi twee skroef reakctor (35.5 na 37 massa %, droog as-vry). Mielie stronke sorg vir ’n hoër opbrengs van bio-olie as mielie strooi in beide reaktore. By die optimum bedryfskondisies is daar in beide reaktor ’n hoër bio-kool opbrengs verkry van mielie stingels teenoor mielie stronke. Geen aansienlike verskille is gevind in die chemise en fisiese kenmerke van van die bio-olie wat geproduseer is in die twee reaktore nie. Daar is wel variasie getoon in die bio-kool kenmerkte van die verskillende Snel Piroliese prosesse. Snel piroliese van mielie-afval lewer energie produkte, bio-olie (HVW = 18.7-25.3MJ/kg) en bio-kool (HVW = 19.8-29.3 MJ/kg) vergelykbaar met steenkool (HVW = 16.2-25.9 MJ/kg). Die bio-olies geproduseer het sommige ongewenste kenmerke getoon byvoorbeeld suurheid (pH 3.8-4.3) asook hoë water inhoud (21.3 – 30.5 massa %). Die metode (indamping) wat gebruik is vir die opgradering van bio-olie het gelei tot die verbetering van die verhittingswaarde asook die toename in viskositeit deur die verwydering van ligte koolwaterstowwe en water. Die mielie-afval bio-kool toon ’n BET (Brunauer-Emmet-Teller) oppervlakte area van 96.7-158.8 m2/g wat dit toepaslik maak as grondstof vir absorbante. The gas geproduseer tydens Snel Piroliese is geanaliseer met behulp van gas chromotografie (GC) as CO2, CO, H2, CH4, C2H4, C2H6, C3H8 and C5+ koolwaterstowwe. Die vlak van CO2 en CO het 80% (v/V) oorskry en met lae verhittingswaardes (8.82-8.86 MJ/kg).
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Bartle, Samantha. "Establishing a new biofuel crop using System Thinking." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86519.
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Thesis (MEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: The complexity of adopting a new crop-based biodiesel feedstock into South Africa given the prevailing environmental, economic and social concerns facing the country are addressed in this study by utilising a Systems Thinking approach. Solaris is a new variety of Tobacco developed specifically as an energy crop over the last twelve years by Italian companies Plantechno and Sunchem. Small-scale trials have been underway over the last year in the Loskop Valley farming community in the Limpopo Province of South Africa. These trials have been managed by the newly-formed local entity, Toboil (Pty) Ltd. In order to assess the viability of introducing Solaris into Loskop in terms of addressing the current diesel and electricity needs of the community and larger over-arching biofuel goals of South Africa, the full System Dynamic Modelling process was employed. This included significant research, stakeholder engagement, a Systems Thinking workshop as well as model development and simulation using the System Dynamics programming tool, Vensim. Following the simulation of various scenarios, it was determined that in order for Solaris implementation to have the greatest impact on the diesel and electricity independence desires of the community, as well as maximising job creation and avoided greenhouse gas emissions, the first five to ten years of implementation may only achieve low to moderate profitability. It was further concluded that if crop-based biofuels are to help meet the rural development goals of South Africa then significant investment and skills transfer is required. In order to address both of these, a modular development process is advocated and should be aided and mentored by members of the commercial farming industry.
AFRIKAANSE OPSOMMING: Die kompleksiteit van die aanvaarding van ‘n nuwe oes-gebaseerde bio diesel roumateriaal in Suid-Afrika in die heersende omgewings-, ekonomiese- en sosiale kommer wat die land ervaar, word in hierdie studie aangespreek deur gebruik te maak van ‘n Sistemiese Denke Benadering (Systems Thinking approach) Solaris is ‘n nuwe variasie Tabak wat deur twee Italiaanse maatskappye Plantechno en Sunchem oor die afgelope twaalf jaar spesifiek as ‘n bron van energie ontwikkel is. Kleinskaalse proewe is gedurende die afgelope jaar in die Loskop Vallei Landbougemeenskap in die Limpopo-provinsie van Suid-Afrika gedoen. Hierdie proewe word onder die toesig van die nuut gevormde plaaslike entiteit, Toboil (Pty) Ltd uitgevoer. Aansienlike navorsing, die aktiewe deelname van die onderskeie belanghebbende partye, ‘n Sistemiese Denke werkswinkel sowel as die ontwerp van ‘n simulasie model deur die gebruik van Sisteem Dinamieke Programerings program, naamlik Vensim, is ingespan om die lewensvatbaarheid van die moontlike aanplanting van Solaris te beoordeel. Die spesifieke gemeenskap se huidige behoeftes aan diesel en elektrisiteit sowel as Suid-Afrika se breër doelwitte aangaande bio-brandstowwe was as die grondslag gebruik waarop die volle Sistemiese Denke Benadering toegepas is. In Loskop omgewing was verskeie moontlike scenarios beproef en daar is op grond daarvan vasgestel dat ten einde die grootste moontlike inpak te maak op die afhanlikheid van diesel en elektrisiteit behoeftes van die gemeenskap, sowel as om die grootste moontlik werkskepping potensiaal te verwesenlik – terwyl die afskeiding van kweekhuis gasse verhoed word - die eerste vyf tot tien jaar van implementering baie lae winsgrens tot gevolg sal hê. Daar is ook verder afgelei dat afsienbare beleggings en opleiding benodig gaan word indien aangeplante bio-brandstowwe aangewend sou word om die landelike ontwikkelingsdoelwitte in Suid-Afrika te verwesenlik. Ten einde beide hierdie doelwitte aan te spreek, word ‘n modulêre ontwikkelings proses aanbeveel waar gevestigde lede van die kommersiële lanbou industrie, bystand en leierskap voorsien.
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Pang, Bairen. "Effect of irrigation on grain sorghum ethanol yield and sorghum mutants on biomass composition." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/38194.
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Master of ScienceDepartment of Biological & Agricultural Engineering
Donghai Wang
Bioprocessing is widely involved in our daily life and significantly relative to the general public because bio-products are widely used in eating, clothing, and living as well as transportation. Due to the public concern of the environmental deterioration, limited fossil fuel resources, and energy price volatility, biofuel as a clean, safe and sustainable energy needs to be developed in response to this growing concern. Sorghum, an important dryland crop, represents a renewable resource currently grown on 8 million acres throughout the United States. Due to climate variability and the continuous decline of water resources, utilization of dryland to grow sorghum and forage sorghum is critically important in order to ensure available energy resources and sustainable economic development. The objectives of this research were 1) to study the impact of deficit irrigation strategies on sorghum grain attributes and bioethanol production, and 2) to evaluate the potential fermentable sugar yield of pedigreed sorghum mutants. Results showed that average kernel weight and test weight of grain sorghum increased as irrigation capacity increased, whereas kernel hardness index decreased as irrigation capacity increased. Starch content increased as irrigation level increased and protein contents decreased as irrigation level increased. Irrigation also had a significant effect on starch properties and bioethanol yield. Sorghum mutants had a significant effect on chemical composition and physical properties such as glucan content, glucan mass yield, ash content, and high heating value, and also had a significant effect on fermentable sugars yield and enzymatic conversion efficiency.
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Veiga, João Paulo Soto. "Biomass to energy: mass and exergy assessment of carbon mitigation and triple bottom line assessment." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-09112016-154413/.
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Earth is exposed to an amount of energy that is fixed organically via photosynthesis and stored as fossil fuels, which are currently the major energy sources of humanity. Since Arrhenius concluded that carbon dioxide emissions from fossil fuels could lead to a climate warming, studies have sought ways to reduce human contribution on the environment to mitigate possible negative impacts on climate. The increasing world population is an obstacle for the efforts to reduce CO2 emissions and other greenhouse gases (GHG), because it demands more energy for transportation, electricity and heating. Among several renewable energy sources, biomass for fuels stands out, such as sugarcane ethanol in Brazil. Using biomass for fuels may help reducing the pressure on fossil fuels, besides, fixing organic carbon already emitted, contributing to mitigate problems of climate change and global warming. Thus, this study aims to analyse carbon cycles of mitigating emissions from fossil fuels with biofuel based on useful energy (exergy) content to determine the equivalent area required. Previous studies of life cycle assessment in sugarcane and eucalyptus were used to obtain carbon- and energy-flow data. These data were applied to estimate the available exergy to the final user through different routes of biofuel production, including current and evolving technologies. Exergy assessment demonstrated that on average, each Mg of biomass produced, led to a change of 3.02 GJ on sugarcane scenarios and 5.93 GJ on eucalyptus scenarios. Reducing sugarcane straw moisture from 50% to 30% increased the exergy output in 13.32 GJ ha-1, an increase of 0.67 GJ ha-1 for each 1% of moisture reduce. Eucalyptus to firewood, reducing moisture from 20% to 15% had an increase of 7.52 GJ ha-1 in the exergy output, representing 1.50 GJ ha-1 of increase for each 1%. This kind of assessment brings a new point of view in carbon mitigation, looking for its functionality. Biofuel use implications in environmental, social and economic aspects were also studied through a hybrid input-output life cycle assessment (IO-LCA) showing differences between the occupation of land use and two different ways of sugarcane production. The IO-LCA showed, in areas of land use change from pasture to sugarcane, energy consumption is increased by 3.7 times, employment is reduced by 5.4 times, and GHG emissions are reduced to only 2% of original emissions for each unit of R$ of final demand changed Most of the employment is generated by the sugarcane supply chain sector. Comparing sugarcane produced by the mills, it originates more direct full time jobs and probably in a more formal job market than sugarcane produced by farm suppliers. Farm suppliers use less energy and release less GHG than mills sugarcane production.A energia à qual o planeta é exposto é fixada organicamente via fotossíntese e estocado na forma de combustíveis fósseis, atualmente, as maiores fontes energéticas da humanidade. Desde que Arrhenius concluiu que emissões de CO2 decorrentes de combustíveis fósseis, poderiam levar a um aquecimento do clima, até os dias atuais, estudos buscam formas de reduzir os impactos antrópicos de forma a atenuar possíveis problemas climáticos. Os esforços para a redução de emissões de CO2 e outros gases de efeito estufa (GEE) têm como obstáculo uma população mundial crescente, que demanda cada vez mais energia para transporte, eletricidade e calor. Dentre as possibilidades de uso de fontes renováveis de energia, a biomassa é uma que se destaca em alguns países, como no caso do uso de etanol de cana-de-açúcar no Brasil. O uso de biomassa para a produção de combustíveis auxilia na redução da pressão para o uso de mais combustíveis fósseis e fixa organicamente o carbono emitido, contribuindo duplamente para a mitigação de problemas com mudanças climáticas e aquecimento global. O presente trabalho analisa os ciclos de carbono em biocombustível, correlacionando-os com sua energia útil (exergia) valorando a equivalência em área para a produção da exergia equivalente de combustíveis fósseis através de uma nova metodologia de avaliação de mitigação. Foram utilizados trabalhos existentes de análise de ciclo de vida em cana-de-açúcar e eucalipto para obtenção dos dados de inventário e fluxos de carbono e energia. Realizaram-se cálculos de exergia disponível ao usuário final com diferentes rotas de produção de biocombustível, abrangendo tecnologias atuais e em desenvolvimento. Na avaliação exergética, reduzir a humidade da palha da cana de 50% a 30% aumentou a exergia disponível em 13,32 GJ ha-1, 0,67 GJ ha-1 para cada 1% de redução na humidade. No caso do eucalipto para combustão, reduzindo-se a umidade de 20% a 15% houve um aumento de 7,52 GJ ha-1, 1,50 GJ ha-1 para cada 1% de umidade. Em média, cada Mg de biomassa produzida aumentou 3,02 GJ em cenários de cana de açúcar e 5,93 GJ em cenários de eucalipto. Este conceito traz uma nova perspectiva na mitigação de carbono, avaliando-o por sua funcionalidade. Também foram estudadas as implicações do uso de biocombustíveis em aspectos ambientais, sociais e econômicos em uma análise híbrida de ciclo de vida e insumo-produto (ACV-IP) evidenciando diferenças entre ocupação do uso de solo e duas maneiras de produção de cana-de-açúcar. A ACV-IP demonstrou que, em áreas de mudança do uso do solo de pastagem para cana de açúcar, o consumo de energia aumenta em 3,7 vezes, o emprego é reduzido em 5,4 vezes, e as emissões de GEE são reduzidas à apenas 2% das emissões originais para cada unidade de R$ de alteração na demanda final. A maior parte do emprego é gerado pelo setor da cadeia de suprimentos de produção de cana. A cana produzida pelas usinas origina mais empregos diretos do que a cana produzida por fornecedores agrícolas. Fornecedores usam menos energia e emitem menos GEE do que a produção de cana por usinas.
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Adamovska, Jana. "A larger laboratory scale investigation into the thermal liquefaction of high potential 2nd and 3rd generation biofuel feedstocks." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/95783/1/Jana_Adamovska_Thesis.pdf.
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This thesis contributes to the development of thermochemical liquefaction as a process for biofuel production. This study investigated residues from sugarcane, energy crops and algae. The potential amount of energy from biomass resources were investigated for each region in Australia. The work was at a larger laboratory scale than other workers which allowed more detailed characterisation of each sample and more thorough investigation of the fuels. Importantly, various bio-crude oils were successfully generated which were comparable with heavy fossil fuel based oils by changing only the processing conditions and without catalytic upgrading.
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McFadden, Kathrine D. "Reverse-selective zeolite/polymer nanocomposite hollow fiber membranes for pervaporative biofuel/water separation." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/39538.
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Pervaporation with a "reverse-selective" (hydrophobic) membrane is a promising technology for the energy-efficient separation of alcohols from dilute alcohol-water streams, such as those formed in the production of biofuels. Pervaporation depends on the selectivity and throughput of the membrane, which in turn is highly dependent on the membrane material. A nanocomposite approach to membrane design is desirable in order to combine the advantages and eliminate the individual limitations of previously-reported polymeric and zeolitic membranes. In this work, a hollow-fiber membrane composed of a thin layer of polymer/zeolite nanocomposite material on a porous polymeric hollow fiber support is developed. The hollow fiber geometry offers considerable advantages in membrane surface area per unit volume, allowing for easier scaling and higher throughput than flat-film membranes.
Poly(dimethyl siloxane) (PDMS) and pure-silica MFI zeolite (silicalite-1) were investigated for these membranes. Iso-octane was used to dilute the dope solution to provide thinner coatings. Previously-spun non-selective Torlon hollow fibers were used as the support layer for the nanocomposite coatings. To determine an acceptable method for coating fibers with uniform, defect-free coatings, flat-film membranes (0 to 60 wt% MFI on a solvent-free basis) and hollow-fiber membranes (0 and 20 wt% MFI) were fabricated using different procedures. Pervaporation experiments were run for all membranes at 65C with a 5 wt% ethanol feed. The effects of membrane thickness, fiber pretreatment, coating method, zeolite loading, and zeolite surface treatment on membrane pervaporation performance were investigated.
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Walker, Devin Mason. "Catalytic Tri-reforming of Biomass-Derived Syngas to Produce Desired H2:CO Ratios for Fuel Applications." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4250.
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This study focuses on upgrading biomass derived syngas for the synthesis of liquid fuels using Fischer-Tropsch synthesis (FTS). The process includes novel gasification of biomass via a tri-reforming process which involves a synergetic combination of CO2 reforming, steam reforming, and partial oxidation of methane. Typical biomass-derived syngas H2:CO is 1:1 and contains tars that deactivate FT catalyst. This innovation allows for cost-effective one-step production of syngas in the required H2:CO of 2:1 with reduction of tars for use in the FTS. To maximize the performance of the tri-reforming catalyst, an attempt to control oxygen mobility, thermal stability, dispersion of metal, resistance to coke formation, and strength of metal interaction with support is investigated by varying catalyst synthesis parameters. These synthesis variables include Ce and Zr mixed oxide support ratios, amount Mg and Ni loading, and the preparation of the catalyst. Reaction conditions were also varied to determine the influences reaction temperature, gas composition, and GHSV have on the catalyst performance. Testing under controlled reaction conditions and the use of several catalyst characterization techniques (BET, XRD, TPR, XAFS, SEM-EDS, XPS) were employed to better explain the effects of the synthesis parameters. Applications of the resulting data were used to design proof of concept solar powered BTL plant. This paper highlights the performance of the tri-reforming catalyst under various reaction conditions and explains results using catalyst characterization.
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Nakashima, Gabriela Tami. "Use of sugarcane trash for solid biofuel production: physicochemical characterization and influence of storage time." Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/8955.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
In the sugarcane plantation it was common to use fire to facilitate the cutting and harvesting of sugarcane. However, Law 11,241 / 02 in São Paulo State provides the gradual elimination of this straw burning of sugarcane. The largest producer of sugarcane in Brazil is the São Paulo State, which has about 4.7 million hectares of planted area. It is estimated that one hectare produces about 14 tons of trash. Therefore, the mills have been trying to incorporate this trash in burning with the bagasse for power generation. However, high concentrations of mineral impurities are impossible its use for energy purposes. The aim of the study was to investigate the influence of storage time and particle size in the physicochemical characterization of the sugarcane trash. It was used the sugarcane trash inside and outside of the bale collected at different storage time (0, 1 and 2 years). The collected material was separated into four different particle sizes (> 0.420mm, 0.250-0.420mm, < 0.250mm and mix). The analyzes involved particle size distribution, proximate analysis, the high heating value (HHV), the chemical analysis of the components of the ashes, the images in the Scanning Electron Microscope (SEM), the Klason lignin content, the holocellulose content and extractives. There were variations in the results of the ash content with different particle sizes. It was observed a higher concentration of mineral impurities in smaller particles (< 0.250mm). The HHV varied from 15.9 to 18.3 MJ.kg-1 and showed no statistical difference for the treatments. The results indicate that the sugarcane trash presents problems related to mineral impurities which constrain its use as a solid fuel in the industry. The particle size interferes in their physicochemical characteristics. The trash can be stored in field and the time storage did not affect the quality for use as solid biofuel.
No manejo da cana-de-açúcar era comum a utilização do fogo para facilitar o corte e colheita da cana. No entanto, a Lei 11.241/02 do estado de São Paulo prevê a eliminação gradual da queima da palha da cana-de-açúcar. O maior produtor de cana-de-açúcar do Brasil é o estado de São Paulo, que possui aproximadamente 4,7 milhões de hectares de área plantada. É estimado que 1 hectare produza cerca de 14 toneladas de palha. Logo, as usinas vêm tentando incorporar esta palha na queima para geração de energia, juntamente com o bagaço. Porém, as altas concentrações de impurezas minerais estão impossibilitando seu uso para fins energéticos. O trabalho teve como objetivo o estudo da influência do tempo de estocagem e da granulometria na caracterização físico-química do palhiço da cana-de-açúcar. Foi utilizado o palhiço de canade-açúcar da superfície e do interior do fardo coletados em diferentes períodos de estocagem, 0, 1 e 2 anos. O material coletado foi separado em 4 granulometrias diferentes (> 0,420mm, 0,250-0,420mm, < 0,250mm e mix). As análises realizadas foram a distribuição granulométrica, a análise imediata, o poder calorífico superior (PCS), a análise química dos componentes das cinzas, as imagens no Microscópio Eletrônico de Varredura (MEV), o teor de lignina Klason, a holocelulose e os extrativos. Houve variações nos resultados do teor de cinzas com as diferentes granulometrias. Observou-se maior concentração de impurezas minerais nas partículas mais finas (< 0,250mm). O PCS variou entre 15,9 a 18,3 MJ.kg-1 e não apresentou diferença estatística para os tratamentos. Os resultados indicam que a palha de cana-de-açúcar apresenta problemas relacionados às impurezas minerais, que dificultam e restringem seu uso como combustível sólido na indústria. A granulometria da palha interferiu nas suas características físico-químicas. O palhiço pode ser estocado no campo e o tempo de estocagem não interferiu na qualidade para o uso como combustível sólido.
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Olarte, Mariefel Valenzuela. "Base-catalyzed depolymerization of lignin and hydrodeoxygenation of lignin model compounds for alternative fuel production." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39613.
Full textAbstract:
This study considered the potential use of lignin as possible renewable fuel and chemical feedstock source. Among the various polymers present in lignocellulosic biomass, the polyaromatic lignin is the one component that is most chemically similar to petroleum. However, it still contains a much larger amount of oxygen compared to crude oil. As such, two strategies were employed in this study: (1) studying the lignin depolymerization in the presence of high temperature and base catalysts; and, (2) employing hydrodeoxygenation as a means to decrease the O/C ratio in lignin-derived model compounds.
The base-catalyzed depolymerization (BCD) of organosolv lignin was done in a 500-mL Monel Parr reactor at temperatures ranging from 165°C to 350°C. Complete solubilization of lignin derivatives was possible in the presence of NaOH and KOH, except at 350°C. NMR experiments revealed formation of oxidized groups (carboxylic and hydroxyl groups) as well as alkyl groups. On the other hand, the use of NH4OH showed N incorporation. Identified and quantified DCM-soluble monomeric compounds were at most 6% of the starting material and are mainly phenolic. This study revealed the apparent susceptibility of syringyl units over guaiacyl units in BCD. This could in turn guide the choice of substrate on which base-catalyzed depolymerization could be applied.
Syringaldehyde was used as the starting material to study batch hydrodeoxygenation (HDO) using several non-cobalt/molybdenum based catalysts. A 50-ml Parr reactor was used, pressurized by 1000 psig of H2 and heated to 300°C. Nickel based catalysts (nickel phosphide, nickel oxide and nickel phosphate) as well as supported precious metals (Pt and Pd) were tested as HDO catalysts. Of the three O-containing functional groups of syringaldehyde, the aldehydic group was found to be the most susceptible. In the presence of the Al2O3-supported catalysts, the methyl groups liberated were found to be incorporated back into the aromatic ring, forming alkylated compounds.
In the last section of this dissertation, hydrothermally synthesized supported Ni on mesoporous silica (MCF) and acid catalysts (HY and H-Al-MCF) were used for probing the effect of bifunctional metal-acid catalysis on phenol hydrodeoxygenation/hydrogenation. Catalyst configurations were varied from the previously studied wet-impregnated Pt/HY catalyst. Based on a hypothesis that coking catalyzed by the acidic zeolite in the wet impregnated Pt/HY catalyst was the main cause of catalyst deactivation and decreased phenol conversion, separately synthesized metal and acid catalyst systems were tested. Complete phenol conversion was sustained for at least three times longer in a continuous flow reactor operated at 200°C and 0.79 MPa of flowing H2. The separation of the metal and acid sites generated a tunable system capable of producing cyclohexanol, cyclohexane or cyclohexene at very high selectivities, even achieving 99% selectivities for cyclohexane.
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Okwo, Adaora. "Next-generation biofuels: the supply chain approach to estimating potential land-use change." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/47603.
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Biofuels, including ethanol and biodiesel, are important components of energy policy in the U.S. and abroad. There is a long history of ethanol production from corn (maize) in the United States and from sugarcane in Brazil. However, there has been a push for greater use of next-generation biofuels (including those derived from cellulosic feedstocks) to mitigate many of the environmental and potential food system impacts of large scale biofuel production.
Farmer willingness to grow biomass crops and ensuring adequate feedstock supply are two important challenges impeding large scale commercialization of next-generation biofuels. The costs of transporting bulky, low density biomass will be substantial. Consequently, in the near term, the economic success of next-generation biofuels will hinge on the supply of locally available biomass. As such, agricultural contracts are expected to be an important tool in overcoming the feedstock acquisition challenge. The broad objective of this study is to understand the effect of contracting for non-food energy crops (cellulosic feedstocks) on the agricultural landscape via the displacement of commodity (food) crops on productive cropland.
We develop an analytical framework for evaluating the design and use of two different contract structures for securing cellulosic feedstock in a representative supply chain with a biorefinery and farmer. We study the dynamics of scarce land and indirect competition from commodity market production on a biorefinery's equilibrium pricing strategy and the resultant supply of cellulosic biomass. And we consider its sensitivity to various production characteristics and market conditions.
We develop a method for quantifying the biorefinery's tradeoff between profit margins and competing for land in order to secure the requisite feedstock for biofuel production. And we characterize the loss of efficiency in the decentralized system, relative to a vertically integrated system, that can be attributed to the need to compete for the farmer's scarce land resource versus that which results from the biorefinery's desire to make a profit.
Then we extend our framework to consider multi-year contracts for biomass production and evaluate the importance of land quality, yield variability and contract structure on a farmer's willingness to accept a contract to produce cellulosic feedstock as well as the resulting impact on the agricultural landscape through the displacement of commodity crops. Using switchgrass production in Tennessee as a case study, we develop feedstock supply curves for each contract structure considered and evaluate the conditions and contract prices at which land devoted to various field crops would be displaced by switchgrass based on field trials of switchgrass production in Tennessee and recent USDA data on crop prices and production.
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Vadlamani, Agasteswar. "Enhanced Biomass and Lipid Productivities of Outdoor Alkaliphilic Microalgae Cultures through Increased Media Alkalinity." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1481307126330107.
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Setter, Cassandra Marie. "Weed Control Effects on Native Species, Soil Seedbank Change, and Biofuel Production." Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/29318.
Full textAbstract:
Aphthona spp. flea beetles were released in the Little Missouri National Grasslands
(LMNG) in western North Dakota in 1999 to control leafy spurge (Euphorbia esula L.). The
changes in soil seed bank composition and leafy spurge density were evaluated on two
ecological sites five (2004) and ten years (2009) after Aphthona spp. release to monitor
the effectiveness of the insects on weed control and associated change in plant
communities. In 2009, leafy spurge stem density averaged 2 and 9 stems m-2 in the loamy
overflow and loamy sites, respectively, compared to 110 and 78 stems m-2, respectively, in
1999 and 7 and 10 stems m-2, respectively, in 2004. Leafy spurge constituted nearly 67%
of the loamy overflow seed bank in 1999 compared to 17% in 2004 and 2% in 2009. In the
loamy seedbank, the weed represented nearly 70% in 1999 compared to approximately
11% in 2004 and 15% in 2009. As leafy spurge was reduced, native species diversity and
seed count increased ten years following Aphthona spp. release. High-seral species
represented 17% of the loamy overflow seedbank in 2009, an increase from 5% in 1999.
However, Kentucky bluegrass, a non-target weedy species, increased over 250% in the
loamy overflow seedbank from 2004 to 2009. The reestablishment of native plant species
has often been slow in areas where leafy spurge was controlled using Aphthona spp. A
bioassay was completed to evaluate native grass establishment when grown in soil from
Aphthona spp. release and non-release sites throughout North Dakota. Native grass
production was not affected when grown in soil collected from established Aphthona spp. sites (1.5 g per pot) compared to soil without insects (1.6 g per pot). The cause of reduced
native grass production in sites with Aphthono spp. previously observed is unknown but
may have been due to a chemical inhibition caused by the insects within the soil that no
longer exists. The native warm-season switchgrass (Ponicum virgotum L.) may be an
alternative to corn for efficient biofuel production; however, control of cool-season grassy
weeds has been a problem in switchgrass production. Various herbicides were evaluated
for smooth bromegrass (Bromus inermis Leyss.) and quackgrass [Elymus repens (L.) Gould]
control in an established switchgrass stand near Streeter, ND and a weed-infested field in
Fargo, ND. Switchgrass yield was higher than the control 14 mo after treatment (MAT)
when aminocyclopyrachlor or sulfometuron were applied early in the growing season, but
no treatment provided satisfactory long-term grassy weed control. Herbicides were
reevaluated at increased rates for smooth bromegrass or quackgrass control in Fargo.
Sulfometuron provided 99% smooth bromegrass control when applied at 280 g ha-1 in the
fall but injured other grass and forb species as well. Sulfometuron would likely be
injurious to switchgrass and could not be used for biofuel production.
Aminocyclopyrachlor did not injure other grass species but only reduced smooth
bromegrass control by 76% when applied at 280 g ha-1 in the fall. No treatment provided
satisfactory long-term quackgrass control.
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Lindfeldt, Erik G. "A trinity of sense : Using biomass in the transport sector for climate change mitigation." Doctoral thesis, KTH, Energiprocesser, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9292.
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This thesis analyses two strategies for decreasing anthropogenic carbon dioxide (CO2) emissions: to capture and store CO2, and to increase the use of biomass. First, two concepts for CO2 capture with low capture penalties are evaluated. The concepts are an integrated gasification combined cycle where the oxygen is supplied by a membrane reactor, and a hybrid cycle where the CO2 is captured at elevated pressure. Although the cycles have comparatively high efficiencies and low penalties, they illustrate the inevitable fact that capturing CO2 will always induce significant efficiency penalties. Other strategies are also needed if CO2 emissions are to be forcefully decreased. An alternative is increased use of biomass, which partially could be used for production of motor fuels (biofuels). This work examines arguments for directing biomass to the transport sector, analyses how biofuels (and also some other means) may be used to reduce CO2 emissions and increase security of motor fuel supply. The thesis also explores the possibility of reducing CO2 emissions by comparatively easy and cost-efficient CO2 capture from concentrated CO2 streams available in some types of biofuel plants. Many conclusions of the thesis could be associated with either of three meanings of the word sense: First, there is reason in biofuel production – since it e.g. reduces oil dependence. From a climate change mitigation perspective, however, motor fuel production is often a CO2-inefficient use of biomass, but the thesis explores how biofuels’ climate change mitigation effects may be increased by introducing low-cost CO2 capture. Second, the Swedish promotion of biofuels appears to have been governed more by a feeling for attaining other goals than striving for curbing climate change. Third, it seems to have been the prevalent opinion among politicians that the advantages of biofuels – among them their climate change mitigation benefits – are far greater than the disadvantages and that they should be promoted. Another conclusion of the thesis is that biofuels alone are not enough to drastically decrease transport CO2 emissions; a variety of measures are needed such as fuels from renewable electricity and improvements of vehicle fuel economy.QC 20100823
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van, Slyke Torry. "Fields of Dreams: Scenarios to Produce Selected Biomass and Renewable Jet Fuels that Fulfill European Union Sustainability Criteria." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-385902.
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Aviation greenhouse gas (GHG) emissions have risen faster than any other transport sector to double between 1990 and 2005. Such emissions from aviation could increase another 700 percent globally, and at least 150 percent in the European Union (EU), by 2050 due to continuously increasing consumer demand. To reverse the trend of rising emissions writ large, the EU has set 2030 climate goals of reducing its GHG emissions by 40 percent (relative to 2005) and having 32 percent of gross final energy consumption from renewables. The EU’s recast Renewable Energy Directive (RED-II) calls for 14 percent of transport energy from renewables, gives multipliers to advanced biofuels, and restricts biomass that is from ecologically valuable lands or that causes land use change. Energy security and energy independence are also long-term EU goals. Many of these goals and targets have also been adopted by the European Free Trade Area (EFTA). Despite these efforts, options are limited to reduce aviation emissions compared to other transport sectors, leaving aviation biofuels, also known as renewable jet fuels (RJFs), as currently the only commercialized option. Against this backdrop, in this thesis scenario analyses were conducted to produce biomass from EU+EFTA lands, project RJF yields from this biomass, and estimate emissions savings of these RJFs compared to petroleum jet fuel. Particular effort was devoted to identifying biomass, biofuels, and EU+EFTA lands that comply with RED-II criteria. The two RJF pathways selected were hydroprocessed esters and fatty acid (HEFA) conversion of Camelina sativa vegetable oil and Fischer-Tropsch (FT) synthesis of forestry residue lignocellulosic biomass. Over 117 million hectares in the EU+EFTA was identified as available for Camelina sativa cultivation, which could yield over 64 Mt of RJF each year, or 113 percent of the total jet fuel consumed in the EU+EFTA in 2017. Conversely, if 50 percent of the forestry residues generated as by-products from EU+EFTA roundwood harvesting operations in 2017 were extracted from harvest sites, 40 Mt of forestry residues would be available as biomass, which would yield almost 7.6 Mt of RJF annually (13% of 2017 jet fuel consumption). If all 144 million hectares of EU+EFTA forest lands deemed available for wood supply were logged, 1,772 Mt of forestry residues would be produced in total (at 50 percent extraction), which could result in almost 337 Mt of RJF, or 590% of the jet fuel consumed in the region in 2017. Hence, RJF can be feasibly produced from biomass from EU+EFTA lands, in amounts that meet or exceed the annual jet fuel consumption of the EU+EFTA, and in ways that meet or exceed RED-II sustainability criteria. However, the proportion of these RJF yields to total annual EU+EFTA jet fuel consumption will decrease over time as the number of flights and their resulting emissions increase. The two RJFs also emit 67 percent and 91 percent fewer GHG emissions, respectively, than petroleum-based jet fuel, showing them to be important tools for the EU to meet its 2030 renewables and emissions reductions targets. Producing the biomass feedstocks and RJFs in these quantities will require the EU to make serious decisions on land use trade-offs, such as whether livestock production is more important than biofuel production.
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Swart, Wessel Johannes. "The economic feasibility of commercial biodiesel production in South Africa including analyses of important production and related parameters." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/19998.
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Thesis (PhD)--Stellenbosch University, 2012.ENGLISH ABSTRACT: In the developed and developing world, the use of lipids for the production of alkyl esters, also known as biodiesel, showed phenomenal growth during the ten year period up to the end of 2007. The main sources for these lipids are the oils extracted from oil seeds such as soya-, palm-, and rape seed, but other products in the food chain such as waste cooking oil (yellow grease) and animal fats are also used. In Africa and Asia vast tracks of land not previously tilled, are now being cultivated to yield oils which are not edible and in a number of countries intensive research is focused on lipid producing species such as algae. Meanwhile more evidence is coming to the fore pronouncing biodiesel and other first generation biofuels not to be the panacea for the predicament the world is facing on unbridled population growth, energy security concerns and environmental issues such as indirect land use changes, global warming and climate changes. The acceptance of the National Biofuels Industrial Strategy at Cabinet level has not yet resulted in significant commensurate activity in South Africa. The availability, other uses and volumes of selected feed stocks for biodiesel production invite debate on the choice between food- and energy security and the appropriateness of some identified socio-economical and socio-political drivers for a viable industry. Somehow the unique characteristics of South Africa and its resources seem not to feature in debate and constraints on the production of biodiesel, as described in this dissertation. The conventional process routes for commercial biodiesel production are based on a mature technology which has inherent pollution and economical limitations. This called for a detailed critical evaluation on process routes more environmentally friendly or involving fewer unit processes generating more desirable products, albeit with more severe process conditions. By comparison, the homogeneous alkali catalyst alcoholysis (HACA), the enzymatic catalyst alcoholysis (ECA) and the super critical alcoholysis (SCA) process routes as developed in this study, are found to be competitive on total manucturing costs as assessed, if results emanating from selected sensitivity analyses and optimisation studies, are accepted. The total manufacturing and operating costs in the selected process routes as estimated, assuming the same capacities for commercial biodiesel production, are dominated by feed stock costs. Incentives on depreciation and fuel levies are deemed not effective, if costs are compared to the price of fossil diesel at the retail level – October 2011. It is concluded that using the feed stocks indicated in the Strategy, commercial biodiesel production is not economically feasible in South Africa at present. In this study process routes and feed stocks were identified that can change this position. Note should be taken of the intensive research activities being conducted on second generation technologies and biorefineries in the developed world, as discussed in this dissertation.
AFRIKAANSE OPSOMMING: In die ontwikkelde en ontwikkelende wêreld het die gebruik van vette vir die produksie van alkielesters, ook bekend as biodiesel, in die tienjaarperiode tot die einde van 2007 fenomenale groei getoon. Die hoofbronne vir hierdie lipiede is die olies onttrek van oliesade soos soja-, palm-, en raapsaad, maar ander produkte in die voedselketting soos gebruikte kookolie en dierevette word ook gebruik. In Afrika en Asië word uitgestrekte stukke grond voorheen onbewerk, nou bewerk om olies wat nie eetbaar is nie, op te lewer, en in verskeie lande word intensiewe navorsing op vetproduserende spesies soos alge gedoen. Intussen kom meer bewyse na vore wat verklaar dat biodiesel en ander eerste-generasie biobrandstowwe nie die wondermiddel is vir die moeilike posisie wat die wêreld in die gesig staar oor onbeteuelde bevolkingsaanwas, kwellings oor energiesekuriteit en omgewingskwessies soos indirekte grondverbruike, aardverwarming en klimaatsveranderings nie . Die aanvaarding van die Nasionale Biobrandstowwe Industriële Strategie op kabinetsvlak het nog nie verhoogde soortgelyke aktiwiteite in Suid-Afrika tot gevolg gehad nie. Die beskikbaarheid, gebruike en volumes van gekose grondstowwe, lok debatte uit oor die keuse tussen voedsel- en energiesekuriteit en die toepaslikheid van sekere geïndentifiseerde sosio-ekonomiese en sosio-politieke stimulante vir ‘n lewensvatbare nywerheid. Op een of ander manier is die unieke kenmerke van Suid- Afrika en sy bronne nog nie in die debat op die knelpunte van biodiesel nie, soos beskryf in hierdie proefskrif. Die gewone prosesroetes vir kommersiële produksie van biodiesel is gebaseer op ‘n beproefde tegnologie met inherente besoedelings- en ekonomiese beperkings. Dit het gevra vir ‘n uitvoerige kritiese evaluasie van meer omgewingsvriendelike- en minder eenheidsprosesse wat meer gewensde produkte genereer, al is dit met erger prosesbepalings. By vergelyking, is dit bevind dat die homogene alkali-katalisator- alkoholisis (HAKA), ensiem-katalisator-alkoholisis (EKA) en die superkritiese-alkoholisis (SKA) prosesroetes soos in hierdie studie ontwikkel, mededingend is op ‘n totale vervaardigingskoste-vlak, as die resultate wat spruit uit geselekteerde sensiwiteitsanalises en optimiseringsstudies, aanvaar word. Die totale vervaardigings- en bedryfskostes soos beraam vir die gekose prosesroetes vir kommersiële biodieselvervaardiging vir dieselfde deursette, word oorheers deur grondstofkostes. Aansporings op afskrywings en brandstofheffings word gesien as nie effektief nie, as kostes vergelyk word met die prys van fossieldiesel op kleinhandelsvlak – Oktober 2011. Die gevolgtrekking word gemaak dat met die grondstowwe aangedui in die Strategie, kommersiële biodieselvervaardiging tans nie ekonomies gangbaar is vir Suid-Afrika nie. In hierdie studie is prosesroetes en grondstowwe geïdentifiseer wat die posisie kan verander. Kennis moet geneem word van die intensiewe navorsingsaktiwiteite op tweede-geslag tegnologieë en bioraffinaderye in die ontwikkelde wereld, soos in hierdie proefskrif bespreek.
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Rismani-Yazdi, Hamid. "Bioconversion of cellulose into electrical energy in microbial fuel cells." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1211313869.
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Vice, President Research Office of the. "Pellet Power." Office of the Vice President Research, The University of British Columbia, 2009. http://hdl.handle.net/2429/9507.
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Duarte, Aires. "Biomass-to-liquids: uma contribuição ao estudo da obtenção de biocombustíveis sintéticos através da síntese Fischer-Tropsch." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/86/86131/tde-16082009-174551/.
Full textAbstract:
Pretende-se estudar um caminho alternativo para a obtenção de biocombustíveis sintéticos, para uso veicular, utilizando-se para tal a rota tecnológica conhecida como Biomass-to-Liquids (BTL) que consiste na utilização da síntese Fischer-Tropsch para a construção de cadeias de hidrocarbonetos a partir de unidades monoméricas obtidas de uma mistura gasosa majoritariamente formada por monóxido de carbono (CO) e hidrogênio (H), conhecida como syngas quando proveniente de fontes energéticas fósseis como o carvão mineral ou o gás natural ou também biosyngas quando proveniente de matéria-prima carbonada renovável, como é o caso da biomassa. O presente trabalho visa abordar o começo dessa cadeia produtiva ao introduzir um conceito para biomassa e os meios para obtenção do biosyngas através do processo conhecido como gaseificação; é feita uma menção à obtenção bem sucedida de biosyngas nas dependências do Instituto de Pesquisas Tecnológicas (IPT) de São Paulo. Segue-se com a utilização desse insumo na síntese Fischer-Tropsch largamente utilizada ao longo do século XX em países específicos para abastecimento da frota veicular local onde seu princípio fundamental é introduzido, assim como os principais mecanismos de formação de cadeias de hidrocarbonetos de diferentes pesos moleculares permitindo assim a obtenção de gasolina e óleo diesel. Essa dissertação apresenta conceitos para a palavra combustível, da mesma forma que introduz os combustíveis fósseis, seus importantes derivados e suas propriedades gerais para que seja possível, adiante, utilizá-los como comparativo com os biocombustíveis sintéticos; é apresentada a evolução histórica dessa tecnologia e são também abordadas a primeira e segunda gerações de biocombustíveis, para se trazer dados que indiquem as vantagens do óleo diesel Fischer-Tropsch quando comparado com seu equivalente oriundo da petroquímica convencional e por fim demonstrar sua superior qualidade sócio-ambiental como biocombustível sintético para o futuro da matriz energética mundial.What is supposed to be on board of this study consists in an alternative way focused on vehicular use synthetic fuels obtaining, using as main process the technological route known as Biomass-to-Liquids (BTL), which one consists on Fischer-Tropsch synthesis use for hydrocarbons chain building starting from monomer units obtained from a gas mixture made up mostly by carbon monoxide (CO) and hydrogen (H), known as syngas from fossil energy sources such as coal or natural gas or also biosyngas from carbonaceous renewable raw materials, such as biomass. This paper aims to address the beginning of the production chain in order to introduce a concept for biomass and the biosyngas obtaining means through the process known as gasification, a reference is made to a successful biosyngas obtaining the dependencies at the Institute for Technological Research (IPT) from Sao Paulo. Then there is the use of that input in the Fischer-Tropsch synthesis widely used throughout the twentieth century, in specific countries, to supply the local vehicle fleet where its basic principle is introduced, as well as the main hydrocarbons chain formation mechanisms thus different molecular weights providing gasoline and diesel oil. This essay presents concepts for the word fuel, the same way that makes it for fossil fuels, their major products and their properties in order to use them as a comparison standard for synthetic biofuels, it was also presented the historical development of this technology and first and second generation of biofuels, in order to bring evidence to suggest the benefits of the Fischer-Tropsch diesel fuel once compared to its conventional equivalent come from the petrochemical and finally to demonstrate it as a socio-environmentally superior quality synthetic biofuel for the future of global energy matrix.
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Ben, Haoxi. "Thermal conversion of biomass and biomass components to biofuels and bio-chemicals." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/51738.
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This thesis examined the conversions of biomass and biomass components to petrochemicals and total aliphatic gasoline like products. There are three major projects of the thesis. Since biomass is very complicated, to understand the thermal decomposition pathways of biomass, the pyrolytic behaviors of various biomass components including lignin and cellulose under different reaction were investigated in the first phase. Due to complexity and limited volatility, the thermal decomposition products from biomass bring insurmountable obstacles to the traditional analysis methods such as GC-MS, UV and FT-IR. Therefore, precise characterization of the whole portion of thermal decomposition products has significant impacts on providing insight into the pyrolysis pathways and evaluating the upgrading processes. Various NMR methods to characterize different functional groups presented in liquid and solid pyrolysis products by 1H, 13C, 31P, 2D-HSQC and solid state 13C-NMR were introduced in the second phase. Nevertheless, the major drawback towards commercialization of pyrolysis oils are their challenging properties including poor volatility, high oxygen content, molecular weight, acidity and viscosity, corrosiveness and cold flow problems. In situ upgrading the properties of pyrolysis oils during thermal conversion process by employing zeolites has been discussed in the third phase. The further hydrogenation of pyrolysis oils to total aliphatic gasoline like products by heterogeneous catalysis in “green medium” – water has also been examined in the third project.
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Funnicelli, Michelli Inácio Gonçalves. "Explorando uma comunidade bacteriana isolada de uma pilha de bagaço de cana-de-açúcar e seu potencial funcional na degradação de biomassa lignocelulósica." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153188.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
RESUMO- Os biocombustíveis são uma alternativa atraente para a substituição de combustíveis fósseis que impulsionaram o interesse global na conversão de biomassa lignocelulósica. Diversos trabalhos são realizados para otimização das etapas para produção de etanol de segunda geração em termos de custo global para o processo. A demanda pela busca de enzimas específicas utilizadas em processos industriais tem impulsionado a prospecção de novas enzimas microbianas com capacidade de desconstruir biomassa vegetal. Dentre elas, as enzimas do grupo das carboidrases são as principais atuantes envolvidas no processo de conversão de biomassa. Diante disso, foi realizada a caracterização de uma comunidade microbiana denominada CB10b, que tem potencialidade em degradar a biomassa. Os estudos foram realizados a partir do sequenciamento total do DNA obtido da comunidade e da prospecção de genes úteis nos processos de conversão de biomassa vegetal. Foram isoladas 6 bactérias pertencentes aos respectivos gêneros: Chitinophaga (que apresentou atividade enzimática em carboximetilcelulose), Pandoraea e Labrys, identificado pelas análises do gene 16S rRNA e da região espaçadora intergênica (ITS) entre os genes 16S-23S rRNA. Por meio das análises dos genes foi possível identificar 16.340 ORFs, sendo anotadas 624 ORFs associadas ao banco de dados do CAZy, distribuídas entre as classes glicosil hidrolases (GHs) com 37,98% (237 ORFs); glicosil transferases (GTs) com 21,63% (135 ORFs); polissacarídeo liases (PLs) com 3,18% (20 ORFs); carboidrato esterases (CEs) com 17,00% (106 ORFs); atividades auxiliares (AAs) com 4,81% (30 ORFs) e módulos de ligação a carboidratos (CBMs) com 15,38% (96 ORFs). Adicionalmente foi possível recuperar através da análise do metagenoma, o genoma parcial de uma bactéria do gênero Pandoraea. Deste modo, o estudo com a comunidade bacteriana CB10b apresentou genes envolvidos a degradação de biomassa lignocelulósica.
ABSTRACT- Biofuels are an attractive alternative for replacing fossil fuels, bringing the world`s attention to the conversion processes of lignocellulosic biomass. Multiple works are currently being done with to optimize the steps in second-generation ethanol production, seeking to reduce the global costs in this process. Demand for specific microbial enzymes is driving the prospection of novel ones able to degrade plant biomass. Among those, carbohydrases are the protagonists in these processes. In this context, we characterized a microbial community called CB10b and tested it`s potential to degrade biomass. We performed studies on this community by total DNA sequencing followed by prospecting genes related to conversion of plant biomass. Six bacteria were isolated, belonging to the genera: Chitinophaga, who presented enzymatic activity on for carboxymethyl cellulose; Pandoraea and Labrys, identified through 16S rRNA and 16S-23S rRNA internal transcribed spacer (ITS) gene analysis. Some 16,340 ORFs were identified, of which 624 were associated with CAZy database, 37.98% (237 ORFs) classified as glycosyl hydrolases (GHs); 21.63% (135 ORFs) as glycosyltransferases (GTs); 17.00% (106 ORFs) were carbohydrate esterases (CEs); 15.38% (96 ORFs) as carbohydrate-binding modules; 4.81% (30 ORFs) as auxiliary activities (AAs) and 3.18% (20 ORFs) as polysaccharide lyase. In addition, it was possible to recover by metagenome analysis the partial genome of a bacterium of the genus Pandoraea. Thus, the study with the bacterial community CB10b presented genes involved the degradation of lignocellulosic biomass.
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Kosa, Matyas. "Direct and multistep conversion of lignin to biofuels." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45836.
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Lignin is the second most abundant biopolymer on Earth, right after cellulose, with a highly complex chemical structure that hinders its possible utilizations. Applications that utilize lignin in different manners are of great interest, due to its inexpensive nature. Present work is based on the notion of converting lignin into different biofuels that have only a few, however important, advantages over lignin as a direct energy source. The first part of current work (pyrolysis) details the analysis of lignin from a relatively new lignin isolation process called LignoBoost. It is obtained from the pulp and paper industry via CO₂ precipitation of lignin from black liquor (BL). This method is environment friendly, results lignin with minimal oxidation, eliminates the main bottleneck of the Kraft cycle (recovery boiler capacity), and yet leaves enough lignin in the process stream to recover pulping chemicals and generate energy for the pulp mill. Pyrolysis had converted this lignin into bio-oil with high aliphatic content and low oxidation level, all advantageous for application as liquid fuel. The second part of this dissertation proved the theory that lignin degradation and lipid accumulation metabolic pathways can be interconnected. Gram-positive Rhodococcus opacus species, DSM 1069 and PD630 were used to evaluate lignin to lipid bioconversion, starting with ethanol organosolv and Kraft lignin. This conversion is a first step in a multistep process towards biodiesel production, which includes transesterification, after lipids are extracted from the cells. Results clearly indicated that the lignin to lipid bioconversion pathway is viable, by cells gaining up to 4 % of their weight in lipids, while growing solely on lignin as a carbon and energy source.
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De, Lauwere Monique Simone. "The biota of the Swartkops Solar Saltworks and their potential for producing biofuels." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1011657.
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The Swartkops and Missionvale salinas in Port Elizabeth on the east coast of South Africa are surrounding by large informal settlements. The runoff from these settlements contributes largely to the eutrophication of the solar saltworks which in turn has an effect on the biotic functioning of the systems, ultimately affecting the quantity and quality of the salt produced. Inorganic nutrients and organic composition, as well as important biological groups were examined within the brine with the aim of comparing the current condition of the same salinas to their condition twelve years ago. Comparisons between inorganic nutrient concentrations and biological groups showed significantly higher inorganic nutrients, with chlorophyll a concentrations in the Swartkops salina in 2011 being significantly higher than in 2012 and the 1999 and 2011 chlorophyll a concentrations being significantly higher than 2012 in the Missionvale salina. Microalgae found in the salinas were cultured in four different growth media. Cells were stained with Nile Red fluorescent dye in order to estimate the extent of lipids production. Five of the most promising lipid producing species were isolated into a monoculture and grown at different salinities to establish the growth and lipid production in response to salinity. Halamphora coffeaeformis and Navicula sp. were found to be the best candidate species. They grew best at salinities between 50 and 70 psu and produced lipid vesicles consuming approximately 10 percent of the cell.
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Wu, Jinzhuo. "Development of economic analysis models for woody biomass to biofuels in central Appalachia." Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/10870.
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Thesis (Ph. D.)--West Virginia University, 2010.Title from document title page. Document formatted into pages; contains vii, 199 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references.
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Nagy, Máté. "Biofuels from lignin and novel biodiesel analysis." Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31668.
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Thesis (Ph.D)--Chemistry and Biochemistry, Georgia Institute of Technology, 2010.Committee Chair: Ragauskas, Arthur; Committee Member: Bunz, Uwe; Committee Member: Deng, Yulin; Committee Member: Singh, Preet; Committee Member: Soper, Jake. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Anieto, Ugochukwu Obiakornobi. "Engineered Microbial Consortium for the Efficient Conversion of Biomass to Biofuels." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc699973/.
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Current energy and environmental challenges are driving the use of cellulosic materials for biofuel production. A major obstacle in this pursuit is poor ethanol tolerance among cellulolytic Clostridium species. The first objective of this work was to establish a potential upper boundary of ethanol tolerance for the cellulosome itself. The hydrolytic function of crude cellulosome extracts from C. cellulolyticum on carboxymethyl cellulose (CMC) with 0, 5, 10, 15, 20 and 25% (v/v) ethanol was determined. Results indicated that the endoglucanase activity of the cellulosome incubated in 5% and 10% ethanol was significantly different from a control without ethanol addition. Furthermore a significant difference was observed in endoglucanase activity for cellulosome incubated in 5%, 10%, 15%, 20% and 25% ethanol in a standalone experiment. Endoglucanase activity continued to be observed for up to 25% ethanol, indicating that cellulosome function in ethanol will not be an impediment to future efforts towards engineering increasing production titers to levels at least as high as the current physiological limits of the most tolerant ethanologenic microbes. The second objective of this work was to study bioethanol production by a microbial co-culture involving Clostridium cellulolyticum and a recombinant Zymomonas mobilis engineered for the utilization of oligodextrans. The recombinant Z. mobilis ZM4 pAA1 and wild type ZM4 were first tested on RM medium (ATCC 1341) containing 2% cellobiose as the carbon source. Ethanol production from the recombinant Z. mobilis was three times that observed from the wild type Z. mobilis. Concomitant with ethanol production was the reduction in OD from 2.00 to 1.580, indicating the consumption of cellobiose. No such change in OD was observed from the wild type. The recombinant ZM4 was then co-cultured with C. cellulolyticum using cellobiose and microcrystalline cellulose respectively as carbon sources. Results indicate that the recombinant ZM4 acted synergistically with C. cellulolyticum to utilize 2.0 g L-1 cellobiose, producing as much as 0.40 mM concentration of ethanol whereas only 0.20 mM ethanol was detected for the wild type ZM4 co-cultured with C. cellulolyticum under the same conditions. A co-culture of the recombinant ZM4 and C. cellulolyticum using 7.5 g L-1 microcrystalline cellulose gave lower ethanol yield than when using cellobiose. In the latter case, the recombinant began producing ethanol in 5 days whereas the wild type required 10 days to produce detectable ethanol. Future efforts will concentrate on identifying the correct concentration of cellulosic substrate at which synergy will be observed using the recombinant ZM4 and other cellulose degrading microorganisms, as well as optimizing medium formulations to better support both organisms.
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Maxwell, Kendra Elaine. "Cationic polymer enhanced hydrolysis of cornstarch for the production of biofuels." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43661.
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The mechanism through which a charged polymer cationic polyacrylamide (C-PAM) operates to increase the rate of cornstarch hydrolysis was investigated. The main objective was to determine the major factors that affect the mechanism so that these parameters may be adjusted to achieve optimal hydrolysis rates. A combination of analytical methods including dynamic light scattering, optical imaging, and uv-vis spectroscopy were used to study polymer, starch, and enzyme interactions as a function of process conditions. It was found that
C-PAM binds strongly to starch granules, increasing solubilization and decreasing onset gelatinization temperature. Granule swelling was unaffected by C-PAM. Both binding of enzyme to cornstarch, and rate of cornstarch hydrolysis were found to increase in the presence of C-PAM. By analogy to previous work on cationic polymer promoted hydrolysis of cellulose, it was proposed that the polymer reduces the charge on the starch surface through a "charge-patch" mechanism. Because both enzyme and substrate are negatively charged, the positively charged polymer reduces the charge repulsion experienced by the approaching enzyme. This leads to stronger enzyme-substrate binding, and faster hydrolysis. There is a mirror image relationship between viscosity of the medium and hydrolysis rate, which allows optimization of these parameters with enzyme and C-PAM dosage. Overall, the polymer addition reduced enzyme dose by 62% depending on the conditions used, so this method could have significant economic impact on the industrial conversion of starch to ethanol.
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Mehlitz, Thomas Hagen. "Temperature Influence and Heat Management Requirements of Microalgae Cultivation in Photobioreactors." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/54.
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Microalgae are considered one of the most promising feedstocks for biofuel production for the future. The most efficient way to produce vast amounts of algal biomass is the use of closed tubular photobioreactors (PBR). The heat requirement for a given system is a major concern since the best algae growth rates are obtained between 25-30 °C, depending on the specific strain. A procedure to determine temperature influence on algal growth rates was developed for a lab-scale PBR system using the species Chlorella. A maximum growth rate of 1.44 doublings per day at 29 °C (optimal temperature) was determined. In addition, a dynamic mathematical model was developed to simulate heating and cooling energy requirements of tubular PBRs for any desired location. Operating the model with hourly weather data as input, heating and cooling loads can be calculated early in the planning stage of a project. Furthermore, the model makes it possible to compare the operation inside a greenhouse to the outdoor operations, and consequently provides fundamental information for an economic feasibility study. The best configuration for a specific location can be evaluated easily. The model was exemplary tested for a hypothetical 100,000 l photobioreactor located in San Luis Obispo, California, U.S.A. Average algae productivity rates of 23% and 67% for outdoor and indoor PBR operations, respectively, were obtained. Actual energy loads (heating and cooling) needed to maintain the PBR at optimal temperature were determined and compared. Sensitivity analyses had been performed for abrupt temperature and solar radiation steps, PBR row distances, ground reflectivities, and ventilation rates of the greenhouse. An optimal row distance of 0.75 m was determined for the specific PBR. The least amount of energy was needed for a ground reflectivity of 20%. The ventilation rate had no major influence on the productivity rate of the system. Results demonstrated the importance of a simulation model as well as the economic impact of a sophisticated heat management system. Energy savings due to an optimized heat management system will eventually increase proficiency of the systems, which will support a new sustainable industry and future developmental potential.
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Wetterlund, Elisabeth. "System studies of forest-based biomass gasification." Doctoral thesis, Linköpings universitet, Energisystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-74576.
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Bioenergy will play an important role in reaching the EU targets for renewable energy. Sweden, with abundant forest resources and a well-established forest industry, has a key position regarding modern biomass use. Biomass gasification (BMG) offers several advantages compared to biomass combustion-based processes, the most prominent being the possibility for downstream conversion to motor fuels (biofuels), and the potential for higher electrical efficiency if used for electricity generation in a biomass integrated gasification combined cycle (BIGCC). BMG-based processes in general have a considerable surplus of heat, which facilitates integration with district heating or industrial processes. In this thesis integration of large-scale BMG, for biofuel or electricity production, with other parts of the energy system is analysed. Focus is on forest-based biomass, with the analysis including techno-economic aspects as well as considerations regarding effects on global fossil CO2 emissions. The analysis has been done using two approaches – bottom-up with detailed case studies of BMG integrated with local systems, and top-down with BMG studied on a European scale. The results show that BMG-based biofuel or electricity production can constitute economically interesting alternatives for integration with district heating or pulp and paper production. However, due to uncertainties concerning future energy market conditions and due to the large capital commitment of investment in BMG technology, forceful economic support policies will be needed if BMG is a desired route for the future energy system, unless oil and electricity prices are high enough to provide sufficient incentives for BMG-based biofuel or electricity production. While BMG-based biofuel production could make integration with either district heating or pulp and paper production economically attractive, BIGCC shows considerably more promise if integrated with pulp and paper production than with district heating. Bioenergy use is often considered CO2-neutral, because uptake in growing plants is assumed to fully balance the CO2 released when the biomass is combusted. As one of the alternatives in this thesis, biomass is viewed as limited. This means that increased use of bioenergy in one part of the energy system limits the amount of biomass available for other applications, thus increasing the CO2 emissions for those applications. The results show that when such marginal effects of increased biomass use are acknowledged, the CO2 mitigation potential for BMG-based biofuel production becomes highly uncertain. In fact, most of the BMG-based biofuel cases studied in this thesis would lead to an increase rather than the desired decrease of global CO2 emissions, when considering biomass as limited.Bioenergi spelar en viktig roll för att nå EU:s mål för förnybar energi. Sverige har med sina goda skogstillgångar och sin väletablerade skogsindustri en nyckelposition vad gäller modern bioenergianvändning. Förgasning av biomassa har flera fördelar jämfört med förbränningsbaserade processer - i synnerhet möjligheten att konvertera lågvärdiga råvaror till exempelvis fordonsdrivmedel. Används gasen istället för elproduktion kan en högre verkningsgrad nås om gasen används i en kombicykel, jämfört med i en konventionell ångturbincykel. De förgasningsbaserade processerna har i allmänhet ett betydande överskott av värme, vilket möjliggör integrering med fjärrvärmesystem eller industriella processer. I denna avhandling analyseras integrering av storskalig biomassaförgasning för drivmedelseller elproduktion, med andra delar av energisystemet. Skogsbaserad biomassa är i fokus och analysen behandlar såväl teknoekonomiska aspekter, som effekter på globala fossila CO2-utsläpp. Forskningen har gjorts på två olika systemnivåer - dels i form av detaljerade fallstudier av biomassaförgasning integrerat med lokala svenska system, dels i form av systemstudier på europeisk nivå. Resultaten visar att förgasningsbaserad biodrivmedels- eller elproduktion kan komma att utgöra ekonomiskt intressanta alternativ för integrering med fjärrvärme eller massa- och papperstillverkning. På grund av osäkerheter i fråga om framtida energimarknadsförhållanden och på grund av de höga kapitalkostnaderna som investering i förgasningsanläggningar innebär, kommer kraftfulla ekonomiska styrmedel krävas om biomassaförgasning är en önskad utvecklingsväg för framtidens energisystem, såvida inte olje- och elpriserna är höga nog att i sig skapa tillräckliga incitament. Medan förgasningsbaserad drivmedelsproduktion kan vara ekonomiskt attraktivt att integrera med såväl fjärrvärme som med massa- och papperstillverkning, framstår förgasningsbaserad elproduktion som betydligt mer lovande vid integrering med massa- och papperstillverkning. Användning av bioenergi anses ofta vara CO2-neutralt, eftersom upptaget av CO2 i växande biomassa antas balansera den CO2 som frigörs när biomassan förbränns. Som ett av alternativen i denna avhandling ses biomassa som begränsad, vilket innebär att ökad användning av bioenergi i en del av energisystemet begränsar den tillgängliga mängden biomassa för andra användare, vilket leder till ökade CO2-utsläpp för dessa. Resultaten visar att när hänsyn tas till denna typ av marginella effekter av ökad biomassaanvändning, blir potentialen för minskade globala CO2-utsläpp med hjälp av förgasningsbaserade tillämpningar mycket osäker. I själva verket skulle de flesta av de förgasningsbaserade drivmedel som studerats i denna avhandling leda till en utsläppsökning, snarare än den önskade minskningen.