Thesis (PH.D.)--Michigan State University. Chemical Engineering, 2008. / Title from PDF t.p. (viewed on Aug. 11, 2009) Includes bibliographical references (p. 179-189). Also issued in print.

M.Sc. / Biofuels have the potential to reduce a country’s dependence on imported oil, to ensure diversity of energy sources, to increase the availability of renewable energy sources and to address global environmental issues. In recognition of the potential benefits of the production and use of biofuels, the Department of Minerals and Energy released the Draft Biofuels Industrial Strategy in December 2006 with the aim to increase the use of biofuels in South Africa to replace 4.5% of conventional transport fuels by 2013. However, there are several barriers that need to be overcome before South Africa can establish a large-scale biofuel industry to achieve the DME’s biofuel target. This includes environmental barriers, such as the availability of land for the cultivation of biofuel feedstocks and potential threats to food security. This study focuses on these environmental barriers and aims to determine the potential for bioethanol production from maize in South Africa to 2013. To this purpose, a bioethanol potential model is developed to simulate the potential for bioethanol production from maize in South Africa between 2008 and 2013. The model incorporates four key elements that all impact on the availability of maize for bioethanol production, namely: maize demand; maize supply; the demand for maize as biomaterial; and the available land area for the cultivation of maize. The study makes further use of the scenario planning method to determine the potential for bioethanol production from maize in South Africa. Four unique bioethanol potential scenarios are designed and simulated within the bioethanol potential model developed for this purpose. Each scenario plays out a differentstoryline for the future social, economic and natural environment that will impact on the availability of maize for bioethanol production. The results of the bioethanol potential scenario simulations show that South Africa will be able to produce enough maize to meet the DME’s biofuel target of 1.2 billion liters of bioethanol for all scenarios between 2009 and 2010. From 2011 onwards, the bioethanol potential decreases below the DME’s target value in both the worst case and rapid change scenarios. The study concludes that the production of bioethanol from maize in South Africa will have various social, economic and environmental consequences for the country’s agricultural sector. The depletion of domestic maize supplies will seriously threaten food security and consequently, increase the country’s dependence on maize imports. This will not only affect the country’s maize producing regions, but spread throughout South Africa as the demand for agriculturally productive land for maize production increases. Domestic food security is therefore at risk and South Africa will have to resort to other energy technologies to achieve a sustainable and renewable energy future for road transport.

The fuel industry in many parts of the world is blending alcohols with motor fuel either to extend the fuel or to improve its octane rating or both. Unfortunately alcohols are hygroscopic and as a result, water becomes a component of the fuel. This can lead to phase separation and the formation of a water-rich layer which could have serious corrosion consequences. In an attempt to understand the phase-splitting in alcohol-petrol-water blends, phase equilibria in ternary systems (alcohol-hydrocarbon-water) have been determined by experiment. The phase equilibria in these ternary systems are also discussed in terms of modern theories of liquid mixtures and the UNIQUAC theory is applied to the "ethanol + benzene + water" ternary system. The alcohols are all the C₁, C₂, C₃ and C₄ alcohols, and the hydrocarbons include those typically found in petrol, e.g. cyclohexane, benzene and substituted benzenes.

Orientador: Jarbas Jose Rodrigues Rohwedder / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-07T20:00:15Z (GMT). No. of bitstreams: 1 Chagas_IsmaelPereira_D.pdf: 2025832 bytes, checksum: 8e2e4a99a15486f48f4aae44dfd6f183 (MD5) Previous issue date: 2006 / Resumo: Neste trabalho, foi desenvolvido um fotômetro NIR portátil para determinar o teor de água em álcool combustível hidratado combustível (AEHC) e o teor de etanol (Álcool etílico anidro carburente) em gasolina. Foram realizados inicialmente estudos espectroscópicos empregando um espectrofotômetro comercial para avaliar quais as melhores regiões do espectro NIR que poderiam ser empregadas para a determinação das espécies de interesse. No desenvolvimento do instrumento foram avaliados detetores baseados em um foto resistor de PbS e um fotodiodo de InGaAs. Dentre os detectores empregados o que apresentou melhores resultados foi o detector de InGaAs. Foram construídos diversos fotômetros sendo que aqueles que apresentaram as melhores performance utilizaram filtro de interferência em 1480 nm e celas cilíndricas com caminho óptico de 2 mm e 5 mm. Para o caminho óptico de 2 mm, foi utilizada como fonte de radiação uma lâmpada de 6 watts, enquanto que para a cela com 5 mm foi utilizada uma lâmpada de tungstênio de 20 watts e uma lente colimadora. Em ambos os casos, a fonte de radiação foi pulsada a uma freqüência de 25 Hz. Como transdutores de saída do instrumento foram empregados um microcontrolador PIC acoplado à um display de cristal líquido e também dois LEDs (vermelho e verde) indicando se o combustível estava dentro ou fora da especificação. O instrumento foi avaliado com amostras comerciais de álcool combustível e gasolina. Para a determinação do teor alcoólico em álcool combustível, a resposta é linear na faixa de concentração de 88 a 98% m/m, com um erro médio de 3,6 % para um total de 30 amostras analisadas, quando comparada ao seu respectivo método de referência. Na análise de amostras de gasolina foi obtida uma resposta linear para o teor de etanol entre 20 % e 30 %, com um erro médio de 3,0% para um total de 40 amostras analisadas. A ANP considera até 4% de erro médio e desta forma o instrumento classifica corretamente 100 % das amostras / Abstract: In this work a portable Near Infrared Photometer to determine the quantity of water in alcohol fuel and the quantity of ethanol in gasoline was developed. Initially, several spectroscopy analysis using a comercial spectrophotometer was made to select the best wavelenghts to determine those fuel quality parameters. The wavelengths of 1480 nm and 1920 nm were selected after preliminary study. The instrument was evaluated using two types of detectors: a PbS photoresistive detector and a InGaAs photodiode. The detector with best performance was the InGaAs photodiode. Different prototypes were built using a interference filter working in 1480 nm and path length with 2 mm and 5 mm. With the 2 mm path length was used a 6 watt tungsten lamp as radiation source and with 5 mm path length was used a 20 watts tungten lamp. This interference filter can be used to determine water in alcohol fuel and ethanol in gasoline without any changes in the instrument. The final version of the prototype showing the best results for both determinations uses a cilindric cell with 5 mm diameter and can be employed for flow or batch measurements, radiation source of a 20 watts tungsten lamp pulsed at 25 Hz and a lens to focus the infrared radiation into the detector. The output transducers of the instrument was a PIC microcontroller with a liquid crystral display and light emission diodes (LEDs) green and red. The instrument was tested using comercial fuel alcohol and gasoline samples. In the determination of water in alcohol it was obtained a linear response in the concentration range from 98 to 88 % (m/m) and in gasoline, it was 20 % to 30 %(v/v). Thirty alcohol samples were analysed showing a standard error of 3,6 % while for the gasoline, a standard error of 3,0% for a total of 40 samples analysed was found. Considering the tolerance of 4%, recommended by the National Pretoleum Agency (ANP), the instrument can classify normal and adultered samples with confidence of 100% / Doutorado / Quimica Analitica / Doutor em Quimica

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No description available.

The motivation for this work stems from the enacting of stricter emissions requirements for the mid 1990's by the California Air Resources Board. It is foreseen that these requirements will favor the use of alcohol fuels in quantities comparable to the present usage of gasoline and diesel in order to reduce emissions of carbon monoxides (CO) and nitrogen oxides (NOx). The use of alcohol fuels at this level will substantially increase the amount of aldehyde emissions. This poses a problem in that aldehydes are odorants, components of photochemical smog, and volatile aldehydes are eye and respiratory tract irritants; therefore, it is only a matter of time before they too are strictly regulated. This thesis focuses on a systematic analysis of aldehyde emissions from alcohol fuels with respect to compression ratio. Compression ratio has been selected as the primary variable for this study, because alcohol-fueled vehicles are usually modified to have higher compression ratios than their gasoline-fueled counterparts in order to take advantage of alcohols' higher octane rating. The investigation is being conducted using a single-cylinder variable-compression ratio Waukesha-CFR engine. The aldehyde emissions are measured for various fuel alcohol percentages at different compression ratios and MBT timing. The effects on conventional vehicle emissions (Le. NOx, CO, unburned hydrocarbons) are also being measured so that tradeoffs between conventional emissions and aldehyde emissions can be determined. The goal of this research was to locate any trends between alcohol fuels and compression ratios which will allow for an optimization of these parameters to minimize aldehyde emissions. It was desired that this be achieved without sacrificing engine performance or increasing other regulated emissions. The variance of compression ratio was found to affect the pollutant formation process via its effects on temperature. The increasing expansion ratio, which accompanies increasing compression ratio, resulted in lower post .. expansion burned-gas temperatures. Temperature's influence on the rate of reactions was found to be the driving force in the formation of most of the pollutants. The experiment showed a definitive reduction in CO emissions with the use of alcohol fuels. The results also indicated an inherent tradeoff between NOx and formaldehyde emissions. / Master of Science

The Piedmont System is a collection of equipment for efficiently removing the juice from sweet sorghum stalks for the production of ethanol. The concept is to separate the whole stalks into pith and rind-leaf fractions, pass only the pith fraction through a screw press, and thus achieve an improvement in juice expression efficiency and press capacity. The operation of three alternative harvesting/processing systems were modeled and compared using computer simulation to determine which system could produce sweet sorghum juice and deliver it to a central plant at the lowest cost per liter of potential ethanol produced. In addition, an energy analysis was done to determine the net energy gain. System A cut the sorghum stalks and hauled them to a crossroads site where they could be stored up to 30 days before juice expression. System B separated the pith and rind-leaf fractions in the field, and juice expression was accomplished at a nearby site. No storage was possible for System B. System C cut the stalks like System A, but then a mobile processor moved through the field to separate the pith and rind-leaf fractions. It was found that the cost of producing feedstock with System C ($0.87/L) was significantly higher than either System A ($0.56/L) or System B ($0.63/L). While the System A cost was slightly lower than that of System B, it is recommended that both Systems A and B should be studied further since small adjustments to the model could eliminate the advantage of System A over System B. Increases in whole-stalk yield and juice sugar level would lower the cost of all three systems by as much as 43%. As the price of energy rises, sweet sorghum is expected to gain an economic advantage over com as a feedstock for ethanol, because of its higher energy ratio. If the by-products are used to produce ethanol through cellulose conversion, the overall energy ratio for sweet sorghum was calculated to be 1.1 compared to 0.8 for corn. The energy ratio if only liquid fuels are considered was 7.9 for sweet sorghum compared to 4.5 for corn. / Ph. D.

Thesis (MBA (Business Management))--University of Stellenbosch, 2007. / ENGLISH SUMMARY: Fossil fuel has been the preferred source for the production of transportation fuel for many years. However, this is not a renewable resource. Many conflicting reports have been published as to how long this resource will last. One thing is certain: eventually the supply of cheap crude oil will run out. It is therefore crucial to start the search for renewable alternatives now. There are a number of possible candidates vying for replacing fossil fuel as primary transportation fuel. Hydrogen, methanol, biodiesel and bioethanol all have the characteristics required of a good transportation fuel. It is unlikely that only one of these will replace oil. A more likely scenario would be that they all play a role in transportation in the future. Apart from being renewable, these alternatives have the further advantage of being less damaging to the environment, something that will become essential in future. Among the renewable alternatives, bioethanol has the second highest energy density. Currently, ethanol production worldwide almost exclusively uses sugarcane and maize as raw material. However, both these are food crops and using them for ethanol could lead to an increase in food prices. Furthermore, there is not enough agricultural land available to produce sufficient quantities of sugarcane and maize for ethanol to replace fossil fuel. Producing ethanol from plant material has the potential to meet the capacity requirements without impacting directly on food production. Approximately 180 million tons of agricultural biomass are produced in the United States each year, sufficient to produce 75 to 110 billion litres of ethanol. Despite its abundance, the technical challenges in converting cellulose to ethanol are significant. One major obstacle to the production of ethanol out of plant material is that most of the sugar in plant material is unavailable for fermentation by micro-organisms. In order to render the sugars in the cellulose fraction accessible to conversion, it is necessary to treat the plant fibres with a combination of chemical and enzymatic processes. Only when a complex mixture of enzymes is used, does it become possible to break down cellulose to glucose for subsequent fermentation to ethanol. Biomass processing by means of enzymes currently involves four separate biological steps: (i) production of enzymes (cellullases and hemicellulases), (ii) hydrolysis of cellulose and hemicellulose to sugars, (iii) fermentation of hexose sugars and (iv) fermentation of pentose sugars. Consolidated BioProcessing (CBP) will combine all these steps into one. However, CBP is not yet possible and the magnitude of research and developmental advancement required to realize this goal is significant. Both sugar and starch ethanol technologies are well established and major process advances are therefore unlikely. Currently there are no commercial-sized plants for the production of ethanol from lignocellulosics, however this is likely to change in the near future considering the progress made in this field during recent years. This study will focus on the current status of the bioethanol industry, as well as on the potential for future development. / AFRIKAANSE OPSOMMING: Fossielbrandstof was vir baie jare die hoofbron vir die produksie van brandstof vir die vervoerbedryf. Fossielbrandstof is nie ’n hernubare energiebron nie en daar is al baie gespekuleer oor presies hoe lank daar nog goedkoop olie beskikbaar sal wees. Baie min van die gepubliseerde bronne stem ooreen, maar almal is dit eens dat olie op een of ander stadium sal opraak. Om hierdie rede is dit noodsaaklik om nou reeds te soek na alternatiewe. Daar is ’n hele aantal hernubare alternatiewe wat gebruik kan word in die plek van olie. Waterstof, metanol, biodiesel en bioetanol beskik almal oor die nodige eienskappe om ’n effektiewe vervoerbrandstof te wees. Die hoofvoordeel van hierdie brandstowwe is dat hulle minder skadelik is vir die omgewing as olie, ’n eienskap wat baie belangrik sal wees in die toekoms. Die kans is eger skraal dat een van bogenoemde bronne die mark totaal sal oorheers soos wat olie tot op hede oorheers het. ’n Meer waarskynlik uitkoms sou wees dat al hierdie bronne op een of ander manier ’n rol gaan speel in die vervoerbedryf in die toekoms. Etanol het die tweede hoogste energie digtheid van die vier genoemde hernubare brandstowwe. Etanol word tans uitsluitlik van suikerriet en mielies geproduseer. Beide suikerriet en mielies is voedselgewasse en die gebruik daarvan vir brandstof kan lei tot ’n toename in voedselpryse. Daar is ook nie genoeg landbougrond beskikbaar vir die verbouing van suikerriet en mieles sodat genoeg etanol geproduseer kan word om fosielbranstof te vergang nie. Die vervaardiging van etanol vanaf lignosellulose het die potensiaal om etanolkapasiteitprobleme te oorkom sonder om direk met voedselproduksie te kompeteer. Ongeveer 180 miljoen ton landbouafval word jaarliks in die Verenigde State geproduseer, genoeg vir die vervaardiging van tussen 75 en 110 biljoen liter etanol. Die tegniese kompleksiteit gekoppel aan die omskakeling van sellulose na etanol is beduidend. Die belangrikste hindernis vir die produksie van etanol vanaf plantmateriaal is die feit dat die meeste van die suiker nie beskibaar is vir fermentasie deur mikroörganismes nie. Plantvesels moet daarom met ’n kombinasie van chemikalieë en ensieme behandel word om sodoende die suiker beskikbaar te maak vir omskakeling. Sellulose kan slegs met ’n komplekse mengsel van ensieme afgebreek word tot glukose wat dan daarna gefermenteer kan word tot etanol. Die verwerking van biomassa met behulp van ensieme behels tans vier afsonderlike biologiese stappe: (i) ensiemproduksie (sellulases en hemisellulases), (ii) hidrolise van sellulose en hemisellulose tot fermenteerbare suikers, (iii) fermentasie van heksose suikers en (iv) fermentasie van pentose suikers. Consolidate BioProcessing (CBP) poog om al vier hierdie stappe te kombineer. Ongelukkig is die CBP proses nog nie moontlik nie en daar moet nog baie navorsing en ontwikkeling gedoen word om dit ’n realiteit te maak. Beide die metodes vir suiker- en styseletanolproduksie is goed gevestig, dus is die kans vir beduidende verbeteringe klein. Daar is tans geen aanlegte van kommersiële grootte vir die produksie van etanol vanaf lignocellulose nie, maar dit gaan waarskynlik binnekort verander as ’n mens die vordering in ag neem wat daar onlangs gemaak is in hierdie veld. Hierdie studie fokus op die huidige stand van sake in die etanolbedryf en die ontwikkelingsmoontlikhede vir die toekoms.

Esta Tese propõe e aplica um método de Avaliação Social do Ciclo de Vida de Produtos. Os indivíduos que compõem o recurso humano desempenham o papel de vetor entre o sistema social e o sistema de produto. Duas categorias de sustentabilidade social são definidas: 1) Atendimento de Necessidades Básicas; e, 2) Autonomia Intelectual. O Indicador desenvolvido para a primeira categoria é a Renda Monetária Anual, medida em unidades monetárias. O indicador desenvolvido para a segunda categoria é a Escolaridade Ajustada pela Duração do Vínculo. A escolaridade dos indivíduos, medida em anos equivalentes de estudo, é multiplicada pelo número de meses em que houve o vínculo entre o sistema social e sistema de produto através de cada indivíduo, no ano de referência da avaliação. Critérios de referência são desenvolvidos para a avaliação dos indicadores. A renda e a escolaridade ajustada são impactadas por fatores que avaliam a gravidade da desigualdade entre os indivíduos do conjunto recurso humano e entre estes e os indivíduos do conjunto consumidor. Os resultados são comparados com valores de referência para condição mínima de sustentabilidade em cada categoria de sustentabilidade. Um modelo matemático é desenvolvido para que nenhum desempenho positivo em uma, ou mais categorias, seja suficiente para anular o desempenho negativo em qualquer categoria, ou categorias, avaliada. Este método é aplicado em uma avaliação preliminar do Álcool Etílico Hidratado Combustível. / A method for Social Life Cycle Assessment of Products is proposed and applied. In this method, the individuals that constitute the human resources play the role of vectors connecting the social system and the product system. Two categories of social sustainability are defined: 1) Basic Needs Fulfillment; and, 2) Intellectual Autonomy. The Annual Monetary Income, in monetary units, is the indicator of the former category. The Job Duration Adjusted Schooling is the indicator of the later category. The individualss schooling, in years of study equivalent, is multiplied by the number of months that the link between the social and the product systems lasted, in the reference year of the assessment. Reference criteria are defined for the assessment of the indicators. The income and the adjusted schooling are impacted by two inequality gravity factors. One factor concerns the inequality gravity among the individuals of the human resource. The other factor concerns the inequality gravity between the individuals in the human resource and the consumer groups. The results are compared to reference values of minimum sustainability for each category of sustainability. A mathematical model for aggregation of category indicators is developed to not allow that a positive result for any category indicator, or set of categories, offsets a negative result in any other sustainability category, or set of categories. This method is applied to a preliminary assessment of the Hydrous Ethyl Alcohol Fuel.