Dissertations / Theses on the topic 'Fuel and energy'
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Salih, Fawzi Mohamed. "Automotive fuel economy measures and fuel usage in Sudan." Thesis, University of Leeds, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293763.
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Hull, Brent. "Fuel cell mositure and energy recovery." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/16428.
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Shandyba, Aleksandr. "The fuel energy prospects of Ukraine." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/10359.
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Khachatryan, Hayk. "Investigation of alternative fuel markets." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Dissertations/Spring2010/h_khachatryan_050310.pdf.
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Chen, Rongjun. "Utilization of upland phytomass for fuel /." [Hong Kong] : University of Hong Kong, 1993. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1354455X.
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Abdullah, Hanisom binti. "High energy density fuels derived from mallee biomass: fuel properties and implications." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/2259.
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Mallee biomass is considered to be a second-generation renewable feedstock in Australia and will play an important role in bioenergy development in Australia. Its production is of large-scale, low cost, small carbon footprint and high energy efficiency. However, biomass as a direct fuel is widely dispersed, bulky, fibrous and of high moisture content and low energy density. High logistic cost, poor grindability and mismatch of fuel property with coal are some of the key issues that impede biomass utilisation for power generation. Therefore, innovations are in urgent need to improve biomass volumetric energy densification, grindability and good fuel matching if co-fired with coal. Biomass pyrolysis is a flexible and low-cost approach that can be deployed for this purpose. Via pyrolysis, the bulky biomass can be converted to biomass-derived high-energy-density fuels such as biochar and/or bio-oil. So far there has been a lack of fundamental understanding of mallee biomass pyrolysis and properties of the fuel products.The series of study in this PhD thesis aims to investigate the production of such high-energy- density fuels obtained from mallee pyrolysis and to obtain some new knowledge on properties of the resultant fuels and their implications to practical applications. Particularly, the research has been designed and carried out to use pyrolysis as a pretreatment technology for the production of biochar, bio-oil and bioslurry fuels. The main outcomes of this study are summarised as follows.Firstly, biochars were produced from the pyrolysis of centimetre-sized particles of mallee wood at 300-500°C using a fixed-bed reactor under slow-heating conditions. The data show that at pyrolysis temperatures > 320°C, biochar as a fuel has similar fuel H/C and O/C ratios compared to Collie coal which is the only coal being mined in WA. Converting biomass to biochar leads to a substantial increase in fuel mass energy density from ~10 GJ/tonne of green biomass to ~28 GJ/tonne of biochars prepared from pyrolysis at 320°C, in comparison to 26 GJ/tonne for Collie coal. However, there is little improvement in fuel volumetric energy density, which is still around 7-9 GJ/m[superscript]3 in comparison to 17 GJ/m[superscript]3 of Collie coal. Biochars are still bulky and grinding is required for volumetric energy densification. Biochar grindability experiments have shown that the fuel grindability increases drastically even at pyrolysis temperature as low as 300°C. Further increase in pyrolysis temperature to 500°C leads to only small increase in biochar grindability. Under the grinding conditions, a significant size reduction (34-66 % cumulative volumetric size <75 μm) of biochars can be achieved within 4 minutes grinding (in comparison to only 19% for biomass after 15 minutes grinding), leading to a significant increase in volumetric energy density (e.g. from ~8 to ~19 GJ/m[superscript]3 for biochar prepared from pyrolysis at 400°C). Whereas grinding raw biomass typically result in large and fibrous particles, grinding biochar produce short and round particles highly favourable for fuel applications.Secondly, it is found that the pyrolysis of different biomass components produced biochars with distinct characteristics, largely because of the differences in the biological structure of these components. Leaf biochars showed the poorest grindability due to the presence of abundant tough oil glands in leaf. Even for the biochar prepared from the pyrolysis of leaf at 800°C, the oil gland enclosures remained largely intact after grinding. Biochars produced from leaf, bark and wood components also have significant differences in ash properties. Even with low ash content, wood biochars have low Si/K and Ca/K ratios, suggesting these biochars may have a high slagging propensity in comparison to bark and leaf biochars.Thirdly, bio-oil and biochar were also produced from pyrolysis of micron-size wood particle using a fluidised-bed reactor system under fast-heating conditions. The excellent grindability of biochar had enabled desirable particle size reduction of biochar into fine particles which can be suspended into bio-oil for the preparation of bioslurry fuels. The data have demonstrated that bioslurry fuels have desired fuel and rheological characteristics that met the requirements for combustion and gasification applications. Depending on biochar loading, the volumetric energy density of bioslurry is up to 23.2 GJ/m[superscript]3, achieving a significant energy densification (by a factor > 4) in comparison to green wood chips. Bioslurry fuels with high biochar concentrations (11-20 wt%) showed non-Newtonian characteristics with pseudoplastic behaviour. The flow behaviour index, n decreases with the increasing of biochar concentration. Bioslurry with higher biochar concentrations has also demonstrated thixotropic behaviour. The bioslurry fuels also have low viscosity (<453 mPa.s) and are pumpable at both room and elevated temperatures. The concentrations of Ca, K, N and S in bioslurry are below the limits of slurry fuel guidelines.Fourthly, bio-oil is extracted using biodiesel to produce two fractions, a biodiesel-rich fraction (also referred as bio-oil/biodiesel blend) and a bio-oil rich fraction. The results has shown that the compounds (mainly phenolic) extracted from bio-oil into the biodiesel-rich fraction reduces the surface tension of the resulted biodiesel/bio-oil blends that are known as potential liquid transport fuels. The bio-oil rich fraction is mixed with ground biochar to produce a bioslurry fuel. It is found that bioslurry fuels with 10% and 20% biochar loading prepared from the bio-oil rich fraction of biodiesel extraction at a biodiesel to bio-oil blend ratio 0.67 have similar fuel properties (e.g. density, surface tension, volumetric energy density and stability) in comparison to those prepared using the original whole bio-oil. The slurry fuels have exhibited non-Newtonian with pseudoplastic characteristics and good pumpability desirable for fuel handling. The viscoelastic behaviour of the slurry fuels also has shown dominantly fluid-like behaviour in the linear viscoelastic region therefore favourable for atomization in practical applications. This study proposes a new bio-oil utilisation strategy via coproduction of a biodiesel/bio-oil blend and a bioslurry fuel. The biodiesel/bio-oil blend utilises a proportion of bio-oil compounds (relatively high value small volume) as a liquid transportation fuel. The bioslurry fuel is prepared by mixing the rest low-quality bio-oil rich fractions (relatively low value and high volume) with ground biochar, suitable for stationary applications such as combustion and gasification.Overall, the present research has generated valuable data, knowledge and fundamental understanding on advanced fuels from mallee biomass using pyrolysis as a pre-treatment step. The flexibility of pyrolysis process enables conversion of bulky, low fuel quality mallee biomass to biofuels of high volumetric energy density favourable to reduce logistic cost associated with direct use of biomass. The significance structural, fuel and ash properties differences among various mallee biomass components were also revealed. The production of bioslurry fuels as a mixture of bio-oil and biochar is not only to further enhance the transportability/handling of mallee biomass but most importantly the slurry quality highly matched requirements in stationary applications such as combustion and gasification. The co-production of bioslurry with bio-oil/biodiesel extraction was firstly reported in this field. Such a new strategy, which uses high-quality extractable bio-oil compounds into bio-oil/biodiesel blend as a liquid transportation fuel and utilises the low-quality bio-oil rich fraction left after extraction for bioslurry preparation, offers significant benefits for optimised use of bio-oil.
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Munzar, Jeffrey. "Laminar flame speed of jet fuel surrogates and second generation biojet fuel blends." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116976.
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An understanding of the fundamental combustion properties of alternative fuels is essential for their adoption as replacements for non-renewable sources. In the aviation industry, a promising candidate is hydrotreated renewable jet fuel (HRJF). HRJF can be synthesized in a sustainable and economically viable manner from long chain fatty-acid methyl esters found in jatropha and camelina seed, and the laboratory-scale characterization of the combustion properties of HRJF is an active area of research. Such research is motivated, in part, by the chemical complexity of biojet fuels which are composed of hundreds of hydrocarbon species, similar to conventional aviation grade fuels. The laminar flame speed has been identified as an important combustion parameter for many combustion applications, and is especially relevant to the aviation community. The laminar flame speed is also an important parameter in the validation of chemical kinetic mechanisms, as it is representative of the chemical reactivity of the fuel. In this study, laminar, atmospheric pressure, premixed stagnation flames were used to determine the laminar flame speed of HRJF blended in varying ratios with Jet A-1 aviation fuel, requiring a combination of experimental and numerical methods. Jet A-1 was also studied to allow for comparative benchmarking of the biojet blends. Experiments were carried out in a jet-wall stagnation flame geometry at a pre-heated temperature of 400 K. Centerline velocity profiles were obtained using particle image velocimetry, from which the strained reference flame speeds were determined. Simulations of each experiment were carried out using the CHEMKIN-PRO software package together with a detailed chemical kinetic mechanism, with the specification of necessary boundary conditions taken entirely from experimental measurements. A direct comparison method was used to infer the true laminar flame speed from the experimental and numerical strained reference flame speeds. In order to model the chemical kinetics of Jet A-1 and the biojet blends, it was necessary to identify a surrogate blend that emulates the reactivity of the biojet fuels, while consisting of a much smaller number of pure compounds. Published data shows significant discrepancies for many jet fuel surrogate components, motivating their inclusion in this study. Thus, laminar flame speeds were also obtained for three candidate jet fuel surrogate components: n-decane, methylcyclohexane and toluene, which are representative of the alkane, cycloalkane and aromatic components of conventional aviation fuel, respectively. Results for the pure surrogate components were used to generate a suitable surrogate blend for the biojet blends. The results form this work resolve conflicting laminar flame speed data for the surrogate components, which is essential for the further development of chemical kinetic mechanisms and contributes to the surrogate modelling of jet fuel combustion. The laminar flame speeds of the biojet blends are compared to the Jet A-1 benchmark over a wide range of equivalence ratios. The biojet blends are found to behave similarly to Jet A-1 for low to moderate levels of blending, but show a marked disagreement otherwise.La comprehension des proprietes de combustion fondamentales des carburants alternatifs est essentielle pour leur adoption en remplacement des sources non renouvelables. Dans le secteur de l'aviation, un candidat encourageant est le carburant d'avion renouvelable hydrotraite (HRJF). HRJF peuvent etre synthetiser de maniere durable et economique en utilisant des esters methyliques a longue cha^ne procure de gras trouves dans les grains de jatropha et de cameline, et la caracterisation a l'echelle laboratoire des proprietes de combustion du HRJF est un domaine de recherche actif. Cette recherche est motivee, en partie, par la complexite chimique des combustibles d'avion biologiques qui sont composees de centaines d'especes d'hydrocarbures conventionnels, semblables a des combustibles d'aviation conventionnel. La vitesse de flamme laminaire a ete identie comme un parametre de combustion important pour de nombreuses applications de combustion, et est particulierement pertinent pour la communaute aeronautique. La vitesse de flamme laminaire est egalement un parametre important dans la validation des mecanismes de cinetiques chimiques, car il est representatif de la reactivite chimique du combustible. Dans cette etude, les flammes laminaire en stagnation, sous la pression atmospherique, et premelangees ont ete utilises pour determiner la vitesse de flamme laminaire de HRJF melanges dans des proportions variables avec du carburant de l'aviation Jet A-1, ce qui exigeait une combinaison de methodes experimentales et numeriques. Jet A-1 a egalement ete etudie pour permettre une analyse comparative des melanges de carburants. Des experiences ont ete menees dans une geometrie de vjet-mur flamme de stagnation a une temperature prechauee de 400 K. Des prols de vitesse centrales ont ete obtenus en utilisant la velocimetrie par image de particules, qui ont permit de determiner les vitesses de flammes de reference tendues. Simulations de chaque experience ont ete realisees en utilisant le logiciel CHEMKIN-PRO en conjunction avec un mecanisme chimique cinetique detaille, avec la specication de conditions aux limites necessaires prises entierement des mesures experimentales. Une methode de comparaison directe a ete utilisee pour deduire la vrai vitesse de flamme laminaire en utilisant les vitesses de flamme de reference tendues experimentales et numeriques. Pour modeliser la cinetique chimique du Jet A-1 et les melanges biologiques, il etait necessaire d'identier un melange de substitution qui emule la reactivite des carburants, tout en comprenant un nombre beaucoup plus restreint de combustibles purs. Les donnees publiees montrent des ecarts importants pour nombreux de ces composants de carburant de substitution, motivant leur inclusion dans cette etude. Ainsi, la vitesse de flamme laminaire a ete egalement obtenus pour trois candidats de composants substitutus pour la carburant d'aviation: n-decane, methylcyclohexane et toluene, qui sont representatifs des composants d'alcane, cycloalcane et aromatiques du carburant d'aviation conventionnel, respectivement. Les resultats pour les composants purs de substitution ont ete utilises pour generer un melange adequat de substitution pour les melanges de carburant biologiques. Les resultats de ce travail resout les conflits entre les donnees de vitesse de flamme laminaire pour les composants de substitution, qui est essentiel pour le developpement des mecanismes de cinetiques chimiques et contribue a la modelisation des carburants vide substitution de la combustion. Les vitesses de flamme laminaire des melanges de carburants biologiques sont comparees a Jet A-1 a dierents rapports d'equivalence. Les melanges biologiques comportent de facon similaire a Jet A-1 pour les niveaux de melange faible a modere, mais montrent un important ecart autrement.
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Kim, Hyea. "High energy density direct methanol fuel cells." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37106.
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The goal of this dissertation was to create a new class of DMFC targeted at high energy density and low loss for small electronic devices. In order for the DMFC to efficiently use all its fuel, with a minimum of balance of plant, a low-loss proton exchange membrane was required. Moderate conductivity and ultra low methanol permeability were needed. Fuel loss is the dominant loss mechanism for low power systems. By replacing the polymer membrane with an inorganic glass membrane, the methanol permeability was reduced, leading to low fuel loss. In order to achieve steady state performance, a compliant, chemically stable electrode structure was investigated. An anode electrode structure to minimize the fuel loss was studied, so as to further increase the fuel cell efficiency. Inorganic proton conducting membranes and electrodes have been made through a sol-gel process. To achieve higher voltage and power, multiple fuel cells can be connected in series in a stack. For the limited volume allowed for the small electronic devices, a noble, compact DMFC stack was designed. Using an ADMFC with a traditional DMFC including PEM, twice higher voltage was achieved by sharing one methanol fuel tank. Since the current ADMFC technology is not as mature as the traditional DMFCs with PEM, the improvement was accomplished to achieve higher performance from ADMFC. The ultimate goal of this study was to develop a DMFC system with high energy density, high energy efficiency, longer-life and lower-cost for low power systems.
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陳榮均 and Rongjun Chen. "Utilization of upland phytomass for fuel." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B29913482.
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Bradley, Thomas Heenan. "Modeling, design and energy management of fuel cell systems for aircraft." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26592.
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Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Parekh, David; Committee Member: Fuller, Thomas; Committee Member: Joshi, Yogendra; Committee Member: Mavris, Dimitri; Committee Member: Wepfer, William. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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de, la Torre Jorge. "FUEL CELLS: HYPE OR REALITY? OVERVIEW OF FUEL CELL TECHNOLOGIES FEASIBILITY STATUS WITH AN EMPHASIS ON AUTOMOTIVE AND RESIDENTIAL PROTON EXCHANGE MEMBRANE FUEL CELLS (PEMFCs)." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1309540374.
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Tajudeen, Ibrahim. "Essays on energy efficiency and fuel subsidy reforms." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/essays-on-energy-efficiency-and-fuel-subsidy-reforms(3066138a-809f-4a4f-aeaf-a1e5f6087891).html.
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This thesis uses innovative approaches to analyse energy policy interventions aimed at enhancing the environmental sustainability of energy use as well as its consequential welfare implications. First, we examine the relationship between energy efficiency improvement and CO2 emissions at the macro level. We use the Index Decomposition Analysis to derive energy efficiency by separating out the impact of shifts in economic activity on energy intensity. We then employ econometric models to relate energy efficiency and CO2 emissions accounting for non-economic factors such as consumers lifestyle and attitudes. The applications for 13 OPEC and 30 OECD countries show that at the country-group and individual country level, increase in energy intensity for OPEC is associated with both deteriorations in energy efficiency and shifts towards energy-intensive activities. The model results suggest that the reduction in energy efficiency in general go in tandem with substantial increases in CO2 emissions. The decline in energy intensity for OECD can be attributed mainly to improvements in energy efficiency which is found to compensate for the impact on CO2 emissions of income changes. The results confirm the empirical relevance of energy efficiency improvements for the mitigation of CO2 emissions. The method developed in this chapter further enables the separate assessment of non-economic behavioural factors which according to the results exert a non-trivial influence on CO2 emissions. Secondly, having empirically confirmed the relationship between energy efficiency improvements and CO2 emission at the macro level in Chapter 2, we investigate potential underlying drivers of energy efficiency improvements taking into account potential asymmetric effects of energy price change in Chapter 3. This is crucial for designing effective and efficient policy measures that can promote energy efficiency. In addition to the Index Decomposition Analysis used to estimate the economy-wide energy efficiency in Chapter 2, we also use Stochastic Frontier Analysis and Data Envelop Analysis as alternative methods. The driving factors are examined using static and dynamic panel model methods that account for both observed and unobserved country heterogeneity. The application for 32 OECD countries shows that none of the three methods leads to correspondence in term of ranking between energy efficiency estimates and energy intensity at the country level corroborating the criticism that energy intensity is a poor proxy for energy efficiency. The panel-data regression results using the results of the three methods show similarities in the impacts of the determinants on the energy efficiency levels. Also, we find insignificant evidence of asymmetric effects of total energy price but there is proof of asymmetry using energy specific prices. Thirdly, in Chapter 4 we offer an improved understanding of the impacts to expect of abolishing fuel price subsidy on fuel consumption, and also of the welfare and distributional impacts at the household level. We develop a two-step approach for this purpose. Key aspect of the first step is a two-stage budgeting model to estimate various fuel types elasticities using micro-data. Relying on these estimates and the information on households expenditure shares for different commodities, the second step estimates the welfare (direct and indirect) and distributional impacts. The application for Nigeria emphasises the relevance of this approach. We find heterogeneous elasticities of fuel demand among household groups. The distributional impact of abolishing the kerosene subsidy shows a regressive welfare loss. Although we find a progressive loss for petrol, the loss gap between the low- and high-income groups is small relative to the loss gap from stopping kerosene subsidy, making the low-income groups to suffer a higher total welfare loss. Finally, from the highlighted results, we draw the following concluding remarks in chapter 5. Energy efficiency appears a key option to mitigate CO2 emissions but there is also a need for additional policies aiming for behavioural change; energy specific prices and allowing for asymmetry in analysing the changes in energy efficiency is more appropriate and informative in formulating reliable energy policies; the hypothesis that only the rich would be worse-off from fuel subsidy removal is rejected and the results further suggest that timing of the fuel subsidy removal would be crucial as a higher international oil price will lead to higher deregulated fuel price and consequently, larger welfare loss.
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Tsay, David 1967. "Feasibility study of fuel cell residential energy stations." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/17002.
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Thesis (S.M.M.O.T.)--Massachusetts Institute of Technology, Sloan School of Management, Management of Technology Program, 2003.Includes bibliographical references.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Electricity provisioning has historically satisfied demand by centralized generation and pervasive distribution through an extensive transmission and distribution network. Once demand increases beyond a fixed threshold, however, the capacity of the generation, transmission and distribution can become crippled and the mal-effects of periodic brownouts and skyrocketing prices may ripple through the nationwide grid system. The traditional response to this constraint is to build new facilities. However, an alternative approach getting increased attention is to satisfy local demands by incrementally investing in distributed generation. Distributed generation facilities can be strategically sited to deliver combined heat and power (CHP) near the source of consumption at unprecedented efficiencies. Presently the distributed generation market remains largely focused on industrial and commercial peak-shaving and emergency back-up applications. The residential market is a frontier yet to be tackled. Residential electricity tariffs, in contrast, are the highest among all sectors and household users are responsible for a large proportion of the peak demand and usage growth. For residential self-generation needs, fuel cell technology is foreseen to be an ideal solution stemming from its low noise, negligible pollution and high efficiency operation. This thesis will assess the market viability of fuel cell technologies for residential distributed generation application. More specifically, the study will consider single household (5 kW) proton exchange membrane fuel cells versus hybrid solid oxide fuel cell with integrated gas turbine (10 kW) technologies for the household end-use and determine the competitiveness and sustainability of each choice.
by David Tsay.
S.M.M.O.T.
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Gustafsson, Filip. "Waste heat recovery systems : Fuel energy utilisation for a marine defence platform." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-19681.
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This report is a thesis for BTH in collaboration with the company Saab Kockums AB. In order to meet future environmental and economical demands, a vessel must reduce its fuel consumption to have a smaller climate impact and save money. Waste heat recovery systems (WHRS) captures the thermal energy generated from a process that is not used but dumped into the environment and transfers it back to the system. Thermal energy storage (TES) is the method of storing thermal energy which allows heat to be used whenever necessary. Some applications of TES are seasonal storage, where summer heat is stored for use in the winter or when ice is produced during off-peak periods and used for cooling later. The purpose of this study is to investigate the possibilities of utilising a vessel’s waste heat by converting thermal energy into electrical energy. This thesis also aims to investigate conditions for SaltX Technology’s nano-coated salt as a potential solution for thermal energy storage. Initially, the expectations and requirements a future WHRS were investigated in a function analysis. Continuously, the method consisted of a combination of a literature review and dialogue with stakeholders. The literature review was used as a tool to identify, select and study concepts of interest built on scientifically proven facts. Dialogues with stake holders were held as a complement to the literature study to find information. The study showed that an organic Rankine cycle has the highest efficiency for low-medium temperature heat and is therefore most suitable to recover thermal energy from the cooling water. The concept of a steam Rankine cycle is most suitable for recovering thermal energy from the exhaust gases for direct use.The study obtained conditions and important properties for storing thermal energy in salt for later use. Finally, the result showed that a Stirling engine is the most efficient concept for conversion of stored energy into electrical energy. The conclusions are that there are great possibilities for waste heat recovery on marine defence platforms. A Stirling engine for energy conversion in combinations with thermal energy storage shows most promise as a future waste heat recovery system on this type of marine platform.Denna rapport är ett examensarbete för BTH i samarbete med företaget Saab Kockums AB. Arbetet utforskar möjligheterna att möta framtida miljömässiga och ekonomiska krav genom att låta fartyg minska sin bränsleförbrukning. System för återvinning av spillvärme (WHRS) fångar upp värmeenergi som vanligtvis kyls ner eller släpps ut i naturen och för den tillbaka till systemet. Termisk energilagring (TES) är metoder för lagring av värme som gör det möjligt att använda termisk energi när det behövs. Vissa applikationer av TES är säsongslagring, där sommarvärme lagras för användning på vintern eller när is produceras under vintern och används för kylning senare. Syftet med denna studie är att undersöka möjligheterna att utnyttja ett fartygs spillvärme genom att omvandla termisk energi till elektrisk energi. Detta examensarbete syftar också till att undersöka förhållandena för hur SaltX Technology’s nanobelagda salt kan användas som en potentiell lösning för lagring av termisk energi. Inledningsvis undersöktes WHRS:s förväntningar och krav i en funktionsanalys. Fortsättningsvis bestod metoden av en kombination av en litteraturstudie och dialoger med intressenter. Litteraturstudien användes som ett verktyg för att identifiera, välja och studera intressanta koncept baserade på vetenskapligt beprövade fakta. Dialoger hölls som ett komplement till litteraturstudien för att hitta information. Studien visade att en organisk Rankine-cykel har den högsta verkningsgraden för låg-medelhög temperatur och därför är bäst lämpad för att återvinna energi buren i kylvattnet samt att en ång-Rankine-cykel är bäst lämpad för att utnyttja energin från avgaserna för direkt användning. Studien erhöll förhållanden för termisk energilagring i salt samt viktiga parametrar för systemet. Slutligen visade resultatet att en Stirlingmotor är det mest effektiva konceptet för omvandling av lagrad energi till elektrisk energi. Slutsatserna är att det finns stora möjligheter för återvinning av restvärme på marina försvarsplattformar. En Stirlingmotor för energiomvandling i kombination med termisk energilagring visar störst potential som ett framtida system för återvinning av spillvärme på denna typen av plattformar.
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Hedström, Lars. "Fuel Cells and Biogas." Doctoral thesis, KTH, Energiprocesser, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-13219.
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This thesis concerns biogas-operated fuel cells. Fuel cell technology may contribute to more efficient energy use, reduce emissions and also perhaps revolutionize current energy systems. The technology is, however, still immature and has not yet been implemented as dominant in any application or niche market. Research and development is currently being carried out to investigate whether fuel cells can live up to their full potential and to further advance the technology. The research of thesis contributes by exploring the potential of using fuel cells as energy converters of biogas to electricity. The work includes results from four different experimental test facilities and concerns experiments performed at cell, stack and fuel cell system levels. The studies on cell and stack level have focused on the influence of CO, CO2 and air bleed on the current distribution during transient operation. The dynamic response has been evaluated on a single cell, a segmented cell and at stack level. Two fuel cell systems, a 4 kW PEFC system and a 5 kW SOFC system have been operated on upgraded biogas. A significant outcome is that the possibility of operating both PEFCs and SOFCs on biogas has been established. No interruptions or rapid performance loss could be associated with the upgraded biogas during operation. From the studies at cell and stack level, it is clear that CO causes significant changes in the current distribution in a PEFC; air bleed may recover the uneven current distribution and also the drop in cell voltage due to CO and CO2 poisoning. The recovery of cell performance during air bleed occurs evenly over the electrode surface even when the O2 partial pressure is far too low to fully recover the CO poisoning. The O2 supplied to the anode reacts on the anode catalyst and no O2 was measured at the cell outlet for air bleed levels up to 5 %. Reformed biogas and other gases with high CO2 content are thus, from dilution and CO-poisoning perspectives, suitable for PEFC systems. The present work has enhanced our understanding of biogas-operated fuel cells and will serve as basis for future studies.QC20100708
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McHenry, John Carl Izaak. "The Challenges of Biofuels in Ohio: From the Perspective of Small-Scale Producers." Ohio : Ohio University, 2008. http://www.ohiolink.edu/etd/view.cgi?ohiou1197926303.
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Buche, Silvain. "Polymer electrolyte fuel cell diagnostics." Thesis, University of Bath, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285318.
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Arespacochaga, Santiago Nicolás de. "Sewage biogas energy valorization via solid oxide fuel cells." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/345237.
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A more sustainable and secure energy supply is required for the forthcoming generations; where the actual dependence on the fossil fuel reserves should be replaced by self-sufficiency and use of renewable energy resources. Conventional sewage treatment is an energy consuming process, or more specifically, an electricity consuming process. Notwithstanding, energy on Waste Water Treatment Plants is not only considered in terms of consumption reduction, but also in terms of production of renewable energy in form of biogas. Today, achieving energy self-sufficiency is limited by the low electrical efficiencies of conventional biogas-powered Combined Heat and Power systems; but fuel cell technology is appearing on the scene in the recent years offering both a higher electrical efficiency and a further reduced environmental impact. Biogas energy valorization in fuel cells combines a high-efficient technology for electrical generation, i.e.: fuel cell, with the use of a renewable fuel, i.e.: biogas.
Raw biogas contains a wide range of contaminants, mainly sulfur and organic silicon compounds (siloxanes), which pose a risk to Solid Oxide Fuel Cell operation; hence biogas requires a thorough conditioning and cleaning process upstream the fuel cell unit. Moreover, monitoring of siloxanes levels remained somewhat controversial with discrepancies on optimal sampling procedure as well as quantification technique; hindering the design and operation of siloxanes removal technologies.
This work is devoted to studying and validating the whole biogas energy valorization line, including the biogas treatment system and the fuel cell operation. The integration of low-cost biological desulphurization and deep polishing physico-chemical adsorption processes with a Solid Oxide Fuel Cell has been studied in an industrial 2.8 kWe pilot plant installed in a Waste Water Treatment Plant in Spain, showing that the stringent gas quality requirements of 0.5 ppmv S and 1 mg Si/Nm3 can be satisfied with over the long-term. The technical and economic comparison of Solid Oxide and Molten Carbonate Fuel Cell performance with conventional Internal Combustion Engines and Micro-Turbines has been also conducted for different plant sizes and raw biogas compositions, confirming the relevant role that fuel cells can play on carbon neutral sewage treatment; particularly in small- and medium-size plants.
Today the final justification for biogas valorization in fuel cell systems needs to be found in environmental issues as some improvements both in the performance and costs are still required. Nonetheless, this thesis demonstrates that the economics for this next-generation technology are expected for the short-term. Further collaborative research between biogas producers, suppliers of biogas treatment systems and manufacturers of fuel cells is required in the near future for Solid Oxide Fuel Cell technology deployment in the sewage sector.El subministrament d'energia sostenible i segur és un dels reptes més rellevants per a les properes generacions, on la dependència actual en les fonts d'energia basades en combustibles fòssils haurà de ser substituïda per l'autosuficiència i l'ús dels recursos energètics renovables. El tractament convencional d'aigües residuals urbanes és un procés que consumeix grans quantitats d'energia, o més específicament, grans quantitats d'electricitat. En aquest sentit, l'energia a les Estacions Depuradores d'Aigües Residuals s'ha de tractar no només en termes de reducció del consum, sinó també en termes de producció d'energia renovable a partir del biogàs. Avui en dia, no és possible assolir l'autosuficiència energètica a causa de les baixes eficiències elèctriques dels sistemes de cogeneració convencionals alimentats per biogàs. Tot i això, en els darrers anys, la tecnologia de les piles de combustible està apareixent en escena, oferint una millor eficiència elèctrica i una reducció en l'impacte ambiental. La valorització energètica de biogàs en piles de combustible combina una tecnologia d'elevada eficiència per a la generació d'energia (la pila de combustible), amb l'ús d'un combustible renovable (el biogàs). S'ha de tenir en compte que el biogàs brut conté una àmplia gamma de contaminants, especialment compostos de sofre i de silici orgànic (siloxans), que comporten un risc operatiu per al correcte funcionament de les piles de combustible d'òxid sòlid. Per tant, s'ha d'instal·lar una etapa d'acondicionament i neteja exhaustiu del biogàs abans que es pugui introduïr a la pila de combustible. D'altra banda, la monitorització de les concentracions de siloxans presenta discrepàncies en relació al procediment òptim per al seu mostreig i en la tècnica analítica de quantificació; dificultant d'aquesta manera el disseny i la operació de les tecnologies d'eliminació d'aquests compostos. Aquest treball es centra en l'estudi i validació de tota la línia de valorització energètica, incloent el sistema de tractament de biogàs i la operació de la pila de combustible. S'ha estudiat la integració de tecnologies de dessulfuració biològica de baix cost i de processos d'adsorció fisicoquímica amb una pila de combustible d'òxid sòlid en una planta pilot industrial de 2.8 kWe instal·lada en una Estació Depuradora d'Aigües Residuals a Catalunya (Mataró). Els resultats experimentals han demostrat que les tecnologies de tractament de biogàs són capaces d'assolir els exigents nivells de qualitat de 0.5 ppmv S i 1 mg Si/Nm3 tant en el curt com en el llarg plaç. Per altra part, s'ha realitzat una estudi tècnic-econòmic comparatiu entre les piles de combustible (d'òxid sòlid i de carbonat fos) amb els motors de combustió interna i les microturbines per a diferents tamanys de planta i composicions del biogàs. D'aquesta manera, s'ha confirmat el paper important que poden jugar les piles de combustible en l'assoliment d'un tractament d'aigües residuals autosuficient; particularment en plantes de tamany petit i mitjà. Avui en dia, els projectes de valorització energètica de biogàs a través de piles de combustible encara s'han de justificar per raons ambientals ja que es requereixen millores tant en el rendiment tècnic com en els costos d'inversió. No obstant, aquesta tesi demostra que aquesta tecnologia de pròxima generació serà econòmicament viable en el curt termini i podrà competir amb les tecnologies convencionals. La investigació col·laborativa entre productors de biogàs, proveïdors de tecnologies de tractament i fabricants de piles de combustible serà imprescindible durant els propers anys per tal que la tecnologia pugui convertir-se en una realitat en el sector del tractament d'aigües residuals urbanes.
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Sevencan, Suat. "Economic Aspects of Fuel Cell-Based Stationary Energy Systems." Doctoral thesis, KTH, Tillämpad elektrokemi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-179137.
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It is evident that human activity has an important impact on climate. Constantly increasing energy demand is one of the biggest causes of climate change. The fifth assessment report of the Inter-governmental panel on climate change states that decarbonisation of electricity generation is a key component of climate change mitigation. Increased awareness of this fact and escalating concerns around energy security has brought public attention to the energy industry, especially sustainable power generation systems. Future energy systems may need to include hydrogen as an energy carrier in order to achieve necessary levels of CO2 emission reductions, and overcome the challenges renewable energy systems present. Fuel cells could be a corner stone of future hydrogen inclusive energy solutions. New solutions like fuel cells have to compete with existing technologies and overcome the shortcomings of emerging technology. Though these shortcomings are well-recognised, fuel cells also have many advantages which makes continued research and development in the field highly worthwhile and viable. Key to their adoption is the identification of a niche market to utilise their advantages while overcoming their shortcomings with continuous research and development. This thesis aims to evaluate some of the stationary fuel cell applications and determine whether one could become the niche market as an entry point for fuel cells. This is achieved by economic evaluations of real and hypothetical applications. Results of the studies here imply that to decrease the total life cycle impacts of fuel cells to more acceptable levels, resource use in the manufacturing phase and recycling in decommissioning should be shown more attention. Results also present a picture showing that none of the applications investigated are economically feasible, given the current state of technology and energy prices. However, fuel cell-based combined cooling, heating and power systems for data centres show the potential to become the niche market that fuel cells need to grow. A further conclusion is that a broad market, longer stack lifetime, the possibility of selling electricity back to the grid and governmental subsidies are essential components of an environment in which fuel cells can permeate through the niche market to the mainstream markets.QC 20151210
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Zhou, Yang. "Predictive energy management for fuel cell hybrid electric vehicle." Thesis, Bourgogne Franche-Comté, 2020. http://www.theses.fr/2020UBFCA020.
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Les véhicules électriques hybrides à pile à combustible ont été largement considérés comme la substitution prometteuse par rapport aux véhicules traditionnels à moteur à combustion interne. Pour réduire les coûts d'exploitation des véhicules, une solution pratique au stade actuel consiste à utiliser efficacement et sainement les systèmes de propulsion hybrides. Une telle tâche peut être remplie via des stratégies de gestion d'énergie fiables, qui coordonnent les sorties de plusieurs sources d'énergie pour satisfaire la demande de puissance des véhicules.Dans un tel contexte, cette thèse vise à concevoir des stratégies de gestion intelligente de l'énergie pour les véhicules électriques hybrides à pile à combustible. Par rapport aux stratégies de contrôle existantes, cette thèse se concentre particulièrement sur la possibilité de combiner les informations de conduite prévues avec le cadre de contrôle optimal en temps réel. Plusieurs techniques de prédiction de conduite sont développées pour estimer les conditions de conduite à venir, comme la vitesse du véhicule, la référence de l’état de charge de la batterie et les informations sur le modèle de conduite. Ensuite, la model predictive control est sélectionnée pour la prise de décision en temps réel, car elle est capable de gérer les systèmes contraints variant dans le temps et est pratique pour l'intégration des informations prédictives de pilotage. Sur la base des résultats prévus et model predictive control, plusieurs stratégies de gestion prédictive de l'énergie sont établies, visant à économiser la consommation d'hydrogène et à améliorer la durabilité des piles à combustible par rapport aux stratégies de référence.La simulation hors ligne et les tests logiciels en boucle ont vérifié la fonctionnalité et l'adéquation en temps réel des stratégies proposéesFuel cell electric vehicles have been widely deemed as the promising substitution against traditional internal combustion engine-based vehicles. To reduce the vehicular operating costs, a practical solution at current stage is to efficiently and healthily use the hybrid propulsion systems. Such task can be fulfilled via reliable energy management strategies, which coordinate the outputs of multiple energy sources to satisfy the vehicular power request.In such context, this PhD thesis intends to devise intelligent energy management strategies for fuel cell hybrid electric vehicles. Compared to existing control strategies, this thesis especially focuses on the possibility of combining the forecasted driving information with the real-time optimal control framework. Several driving prediction techniques are developed to estimate the upcoming driving conditions, like the vehicle’s speed, battery state-of-charge reference and driving pattern information. Thereafter, model predictive control is selected for real-time decision-making, since it is capable of handling the time-varying constrained systems and is convenient for the integration of driving predictive information. Based on the forecasted results and model predictive control, several predictive energy management strategies are established, aiming at saving hydrogen consumption and enhancing fuel cell durability versus benchmark strategies.Both offline simulation and software-in-the-loop testing have verified the functionality and real-time suitability of the proposed strategies
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Shcherbak, V. V. "The influence of fuel and energy companies to environment." Thesis, Sumy State University, 2014. http://essuir.sumdu.edu.ua/handle/123456789/45219.
Full textAbstract:
Today’s changes in the environment are the negative result of human activities. Deforestation, drying ponds, construction the plants - leaded to global changes in our ecology. Energy sector consists ofextractive, convertible, transportablecompaniesand influences badlyhydrosphere, atmosphere, biosphere andlithosphere.
Energy efficiency, energy saving and resource saving are explored as a step to better environment. Consequently, modern fuel and energy companies should be reconstructed.
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Khallat, Mohamed Ali. "A methodology for evaluating photovoltaic-fuel hybird energy systems." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/53626.
Full textAbstract:
A major issue encountered in the large scale use of Photovoltaic (PV) energy sources for the production of electricity is the variability of the resource itself. Extensive fluctuations of the PV generation may cause dynamic operational problems for an electric utility. In order to remedy this situation it is proposed that fuel cell power plants be operated in parallel with PV arrays. This hybrid operation will help to smooth out the fluctuating PV output. Because of its high ramping capability the fuel cell will be able to absorb such fluctuations.
An overall methodology is presented to evaluate the PV system in a large utility. This methodology has two parts-planning and operation. The aim of the planning study is to determine the capacity credit of a PV system based on the loss of load probability (LOLP). Long term SOLMET data is used to determine the nature of available insolation at a particular site. The expected value of hourly insolation is used in the planning study. The aim of the operation study is to validate the results of planning study in the shorter operational time frame, and determine the fuel cell requirements and associated operating cost savings for each penetration level of PV.
A technique to find the maximum penetration level of PV, without causing any economic penalty, is presented. It is found that the penetration level can be increased up to 15.62% of peak load by adding fuel cells to the system under consideration. The annual peak load for this system is taken as 6400 MW. It must be mentioned here that, similar evaluations for other systems may yield somewhat different results. This technique is general enough such that it can be used for other intermittent sources of generation as well.Ph. D.
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Laguna, Bercero Miguel A. "Hydrogen and fuel cells: an efficient and clean energy alternative." Revista de Química, 2014. http://repositorio.pucp.edu.pe/index/handle/123456789/100084.
Full textAbstract:
El avance tecnológico más importante de las próximas décadas pasa por el uso del hidrógeno como combustible, sustituyendo el consumo masivo de los combustibles fósiles. De esta manera, utilizando tecnologías basadas en pilas de combustible, conseguiremos sistemas energéticos más eficientes que los actuales y, además respetuosos, con el medio ambiente.The most important technological development in the coming decades will be the use of hydrogen as an alternative to the widely used fossil fuels. By the use of fuel cell based technologies, it will be feasible to produce energy systems that will be more efficient than the current ones and that will also be environmentally friendly.
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Sinuka, Yonwaba. "Performance testing of a diesel engine running on varying blends of jatropha oil, waste cooking oil and diesel fuel." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2436.
Full textAbstract:
Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2016.The high cost of fossil fuels and the fact that the world has arguably reached its peak oil production, has driven the need to seek alternative fuel sources. The main objective of the current study is to determine the performance of a laboratory-mounted diesel engine when fuelled with varying laboratory prepared biofuel and biodiesel and whether the advancement of the injection timing parameters will improve the engine power output and improve the smoke effect of these different fuel blends. The laboratory prepared biofuels used in this project range from 100% bio-fuel (BF100) to 50%, 30% and 10% biodiesel blends (BF50, BF30 and BF10, respectively). It should be noted that these blends are not commercially available, since they were blended in the laboratory specifically for these tests. The overall results of the study show that there is a distinct opportunity for using certain bio-fuel blends in specific applications as the power outputs are no more than one quarter less than that of base diesel. Concomitantly, the smoke opacity in all of the blends is lower than that of base diesel, which is a significant benefit in terms of their overall air emissions.
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Tatum, Shaun Wesley Jackson John D. "The ethanol market an econometric inquiry into the market for E85 /." Auburn, Ala., 2007. http://repo.lib.auburn.edu/2007%20Fall%20Theses/Tatum_Shaun_38.pdf.
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Willmot, Peter. "Fuel from straw : an in-field briquetting process." Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/19382.
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Disposal of large quantities of surplus straw, which lie in the fields after harvest, is a major annual problem to cereal farmers. The current preferred solution of burning the straw where it lies is environmentally unsatisfactory and appears to be a huge waste of a potentially valuable, renewable energy source. None of the currently available straw packaging systems provides an economically viable alternative. A process is proposed for producing industrial quality fuel briquettes using a tractor towed implement. The economic feasibility of such a system is investigated and comparisons are made with existing straw disposal methods. The projected cost of fuel, produced in this way, is compared with prevailing fossil fuel prices. A multistage continuous process machine concept is described and the various stages are proven workable both experimentally, in the laboratory, and analytically. Laboratory experiments determine the forces required to produce acceptable quality briquettes and comparisons are made between the power available from the tractor, the economical throughput rate and the energy consumed in the compaction process. The mechanism of bonding within the straw packages, under compression, is examined so that the parameters necessary to give the optimum machine design may be understood. The effect, on briquette quality, of variations in die shape within the constraints imposed by the machine concept is fully investigated. Experiments extend to compression at speeds representative of 'live' field operation and a die shape is developed which produces packages of consistently good durability. Many of the design ideas put forward in this thesis have now been incorporated in an original prototype machine, built and successfully field-tested by the company who has supported this project and now holds the relevant patents.
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エドアード, ラマス ホルヘ, and Jorge Eduardo Lamas de Anda. "Conceptual study on the energy independence of fuel cell cogeneration systems using solar energy." Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB12981850/?lang=0, 2016. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB12981850/?lang=0.
Full textAbstract:
この論文では従来電力系統から自立的に利用出来る太陽エネルギー及び燃料電池コジェネレーションシステムの徹底的な解析が述べられている。開発した水素マイクログリッドの燃料依存を最小化にする数理モデルを利用し日本社会でのさまざまなシナリオのシミュレーションが行なわれた。こういうシステムの実現性が従来水素燃料供給方法の審査及び日本の中型離島の事例研究で評価された。経済的な分析によって石油の価格が高い遠隔な地域では水素マイクログリッドは競争力があると分かった。This thesis presents a thorough analysis on energy supply systems using solar energy and fuel cell cogeneration systems that can operate reliably and independently from the main power grid. A mathematical model to maximize fuel independence for hydrogen micro-grids is developed and simulated for various scenarios in Japanese communities. The viability of implementing such systems is assessed with a review of available hydrogen supply channels, and a study case for a remote Japanese island of medium size. An economic analysis of this study suggests that hydrogen micro-grids are economically competitive for energy supply in remote areas where oil prices are high.
博士(工学)
Doctor of Philosophy in Engineering
同志社大学
Doshisha University
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Al, Nur Maglub. "Automobile fuel efficiency and gasoline demand : models and inter-country comparisons." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333056.
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Fapetu, Segun. "Enhancing energy recovery from industrial wastewater using microbial fuel cells." Thesis, University of Westminster, 2018. https://westminsterresearch.westminster.ac.uk/item/q9480/enhancing-energy-recovery-from-industrial-wastewater-using-microbial-fuel-cells.
Full textAbstract:
Microbial fuel cells (MFCs) hold great promise for the simultaneous treatment of wastewater and electricity production. However, the electricity recovery needs improvement if MFCs are to compete with already established technologies e.g. anaerobic digestion. The aim of this study was to investigate ways of enhancing electricity recovery from (synthetic) industrial wastewater. Initial studies investigated the use of defined cocultures as a way of improving turnover of substrate and hence electricity produced by exploiting mutualistic relationships such as syntrophy or ability of facultative microoganisms (Saccharomyces cerevisiae) to consume residual oxygen from the anode. A coculture of Shewanella oneidensis and Clostridium beijerinckii, investigated here for the first time, gave a power production of 87 mW m-2 compared to 48 mW m-2 for S. oneidensis alone or 60 mW m-2 for C. beijerinckii alone. Substrate degradation was also improved significantly from 20% (S. oneidensis alone) to 67% using the coculture. Similar improvements were observed for novel cocultures of G. sulfurreducens, S. cerevisiae and C. beijerinckii as well as cocultures of C. beijerinckii, S. oneidensis and S. cerevisiae. To improve electricity recovery from MFCs, mechanisms of electron transfer need to be understood. The contribution of direct electron transfer mechanisms to overall electron transfer was investigated for the first time by restricting S. oneidensis cells close to or away from an anode electrode. A maximum power output of 114 mW m−2 was obtained when cells were retained close to the anode. This was 3.5 times more than when the cells were separated away from the anode. This result was corroborated by another study where S. oneidensis cells were entrapped in alginate gels. To further investigate the contribution of the c-type cytochromes forming the Mtr pathway to extracellular electron transfer, Rapid DNA Prototyping Assembly was used for the first time to assemble Mtr-pathway coding genes individually or as operons. The different constructs were overexpressed in S. oneidensis and heterologously expressed in E. coli and power production compared with the wild type strains. The best power generated was from the mtrAB S. oneidensis strain (144 mW m-2) and from the mtrCAB E. coli strain (24 mW m-2). Since electricity production is linked to exoelectrons forming a biofilm on the anode, ways of enhancing biofilm formation were sought. The quorum sensing molecule N (-3-oxodecanoyl)-L-homoserine lactone of different concentrations was for the first time exogenously added to MFCs and its effect on biofilm formation and power production determined. The results were compared with control experiments without N (-3-oxodecanoyl)-L-homoserine lactone. The results indicated that power production of 184 mW m-2 , the highest obtained of all approaches taken in this investigation, could be obtained when 10 uM of the chemical was added compared to 56 mW m-2 for the control, with significant increases in biofilm density. Taken together, these results highlight the importance of using defined cocultures (e.g. for bioaugmentation of working MFCs), direct electron transfer mechanisms, overexpression of the Mtr-pathway and need to increase biofilm density on anode surfaces, for enhancing electricity recovery in microbial fuel cells.
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Zhang, Yusheng. "Development of a bench scale single batch biomass to liquid fuel facility." Thesis, University of Fort Hare, 2014. http://hdl.handle.net/10353/811.
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The research described in this dissertation was motivated by the global demand for energy that is not dependent on coal, oil, natural gas and other non-renewable fossil fuels. The technology used in this project is related to the use of biomass to produce a viable alternative to conventional sources of fuel. A bench scale biomass to liquid (BTL) facility was built and tested. This produced results confirming the feasibility of the BTL process. The findings of the pilot study outlined in this dissertation justified the conclusion that the next step will be to expand the capacity and productivity of the BTL pilot plant to an industrial scale. Biomass comes from a variety of renewable sources that are readily available. In this case, the material used in the fixed bed biomass gasification facility to generate wood gas was agricultural and forestry waste, such as straw and wood chips. The gasifier had the capacity to produce up to 10 cubic metres/hr of gas with a carbon monoxide and hydrogen content of between 20–40% by volume, when it was operated at ambient pressure and with air as the oxidizer. The gas, produced at a temperature above 700º C, was cooled in a quench/water scrubber in order to remove most of the mechanical impurities (tars and water-soluble inorganic particles), condensed and dried with corn cobs before being compressed in cylinders at over 100 bar (g) for use in the Fischer-Tropsch Synthesis (FTS). The syngas was subjected further to a series of refining processes which included removal of sulphur and oxygen. The sulphur removal technology chosen entailed applying modified activated carbon to adsorb H2S with the help of hydrolysis in order to convert organic sulphur impurities into H2S which reduced the sulphur content of the gas to less than 5 ppbv. Supported cobalt catalyst (100 grams), were loaded into a single-tube fixed bed FT reactor with an inner diameter of 50 mm. The reactor was fitted with a heating jacket through which, heated oil ran to cool the reactor during a normal reaction occurring at < 250 ºC, while nitrogen was used in the heating jacket during reduction, which occurred at temperatures up ~ 350 ºC. The FTS reaction was carried out at different pressures and temperatures. Liquid and wax products were produced from the facility. The properties of the liquid and solid hydrocarbons produced were found to be the same as FT products from other feed stocks, such as natural gas and coal.
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Ferreira, S. B. "Thermoeconomic analysis and optimisation of biomass fuel gas turbines." Thesis, Cranfield University, 2002. http://hdl.handle.net/1826/3423.
Full textAbstract:
The ready availability of biomass in Brazil makes this type of fuel a major
candidate to integrate the country's energy matrix. Although this fuel is used as a
primary energy source, its use for electricity generation is still modest. On the other
hand, high efficiency and power density achieved by modem gas turbine engines make
them a promising option for the power generation market. Thus, this thesis has as main
objective to analyse the marriage between the solid fuel, biomass in this case, and gas
turbines.
Two main types of power plants are studied; the biomass integrated gasification
gas turbine cycle (BIGGT) and the externally fired cycle (EFGT), which for the first
time is thoroughly studied for the use of biomass fuel, plus the intercooled and
recuperated variants of these power plants. The results are compared with the ordinary
natural gas fuelled cycle. The method involves on- and off-design point performance
and exergy analysis. The economic performance and optimisation for each cycle is also
explored in order to assess their feasibility. The optimisation technique adopted is the
Genetic Algorithm (GA) connected to the conventional hill-climbing methodology. This
merge uses the GA to identify the region of optimum values, which are then passed on
to the hill-climbing algorithm. In this way the long time demanded by the GA to
converge is shortened and the unreliability of the hill-climbing method in finding the
global optimum is overcome.
The codes developed for design-point performance analysis and optimisation,
compared with a commercial package, proved reliable and robust. The tools developed
for exergy analysis (on- and off-design) are also robust and flexible, with the capability
of analysing and calculating the properties of mixtures made of 23 different gases. The
emissions equations are sufficiently accurate for the purposes of this thesis. The
relationship proposed for calculating the variable operating and maintenance costs
proved to be consistent with the current knowledge.
The results show that the optimised cycles are competitive with current
technology in terms of cost of electricity, the EFGT being the more competitive
biomass cycle, with costs of electricity (US$ 0.07/kWh) comparable with those of the
natural gas fuelled power plants. The BIGGT in its turn shows a cost of electricity 29
percent higher than its natural gas and externally fired counterparts (US$0.09/kWh)
counterparts. The method used to work out the best investment
- the required revenue
(RR) method -
demonstrated that the EFGT is again comparable with the NGGT cycle,
with its RR being only 7 percent higher. The BIGGT cycle shows a higher RR due to its
costly gasification/cleaning system. The minimisation of the exergy destruction ratio
indicates that little improvement would be achieved after the reduction of this
parameter, and a penalty - an 85 percent increase in the cost of electricity - must be
paid.
The environmental advantage of the biomass-fuelled cycles over the natural gas
cycle is clear, making these systems very promising as low emissions alternatives. Both
BIGGT and EFGT cycles presented very low CQ2 emissions. Regarding NO., emissions,
the EFGT cycle has the lowest rates, whereas the BIGGT has the highest.
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Waite, Ian Vowles. "Refuse-derived fuel for electricity generation in the UK." Thesis, London South Bank University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323891.
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Gammon, Rupert. "The integration of hydrogen energy storage with renewable energy systems." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/7847.
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This thesis concerns the design, implementation and operation of a hydrogen energy storage facility that has been added to an existing renewable energy system at West Beacon Farm, Leicestershire, UK. The hydrogen system consists of an electrolyser, a pressurised gas store and fuel cells. At times of surplus electrical supply, the electrolyser converts electrical energy into chemical energy in the form of hydrogen. This hydrogen is stored until there is a shortage of electrical energy to power the loads on the system, at which point it is reconverted back to electricity by the process of reverse-electrolysis that takes place within a fuel cell. The renewable energy sources, supplying electrical power to domestic and office loads at the site, are photovoltaic, wind and micro-hydroelectric. This work is being carried out through a project, conceived and overseen by the author, known as the Hydrogen and Renewables Integration (HARI) project. The purpose of this study is to demonstrate and gain experience in the integration of hydrogen energy storage with renewable energy systems and, most importantly, to develop software models that could be used for the design of future systems of this type in a range of applications. Effective models have been created and verified against the real-world operation of the system. These models have been largely completed, although some minor details remain unfinished as the are dependant upon studies linked to this one which are yet to be concluded. Subject to some fine tuning that this would entail, then, the models can be used to design a stand-alone, integrated hydrogen and renewable energy system, where only the load profile and weather conditions of a site are known. Significant practical experience has been gained through the design, installation and two years' of operation of the system. Many important insights have been obtained in relation to the integration of the system and the design and operation of its components.
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Donovan, D. G. "Industrial response to wood-fuel scarcity in the hill region of Nepal." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317808.
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Khorassani, Nader James. "The Dragon's Fuel: Developing Chinese-Iranian Cooperation." Thesis, Boston College, 2010. http://hdl.handle.net/2345/1342.
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Thesis advisor: Robert RossIn recent years, economic and political cooperation between China and Iran has deepened to levels never before reached. This thesis discusses the potentially far reaching implications the development in relations between China and Iran poses for controlling nuclear proliferation, international energy security, and the role the US plays in Middle Eastern and East Asian power politics. Monitoring the Chinese-Iranian relationship is thus important to the US, as its own influence across the globe could potentially be reduced as a result of cooperation between these two nations. With China newly confident following the global financial crisis of 2008, it appears that despite US pressure to stop, China is continuing to deepen its cooperation with Iran in pursuit of its own national interests
Thesis (BA) — Boston College, 2010
Submitted to: Boston College. College of Arts and Sciences
Discipline: Political Science Honors Program
Discipline: Political Science
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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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Sanchez, Antonio. "Energy management in electric systems fed by fuel cell stacks." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00590217.
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The growth of distributed energy resources together with the incorporation of new technologies in the generation and storage of energy are imposing new control and operational strategies. Due to its storage capability and that it is considered to be clean energy; fuel cell (FC) is one of the most promissory technologies as a stationary energy source in micro grids and also in transportation applications. Therefore, two main issues are addressed in this work; the conception, design, and setup of a fully instrumented test bench for proton exchange membrane (PEM) FC stacks and the design and experimental test of a new dynamic energy-exchange control strategy for multi source and multi load systems. To define the test bench instrument requirements, in the first part a complete dynamic model review is given. In the next section, relevant information regarding the setup of the FC test bench design and implementation is included, i.e., specification criteria of the instruments and acquisition and data display system. Some experimental results are performed in order to demonstrate the potentialities of the setup. In the following chapter, a new dynamic energy exchange control strategy (DSER) is introduced and tested in a two port system via simulation and experimentation. In order to establish a comparison and integrate the DSER in a FC application, in the fifth chapter a three port system - including a static model of FC - and two different control approaches, are tested via simulation. The thesis is closed with some concluding remarks and some potential research topics generated from this work.
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Li, Huan. "Energy consumption minimization strategy for fuel cell hybrid electric vehicles." Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCA034/document.
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Le réchauffement climatique, la pollution de l'environnement et l'épuisement des énergies pétrolières ont attiré l'attention de l'humanité dans le monde entier. Les véhicules électriques hybrides à pile à combustible (FCHEV), utilisant l’hydrogène comme carburant et n’émettant aucune émission, sont considérés par les organismes publics et privés comme l’un des meilleurs moyens de résoudre ces problèmes. Cette thèse de doctorat considère un FCHEV avec trois sources d'énergie: pile à combustible, batterie et supercondensateur, ce qui complique l'élaboration d'une stratégie de gestion de l'énergie (EMS) pour répartir la puissance entre différentes sources d'alimentation. Parmi les méthodes de gestion de l'énergie de la littérature actuelle, la stratégie de minimisation de la consommation équivalente (ECMS) a été sélectionnée car elle permet une optimisation locale sans connaissance préalable des conditions de conduite et cela en donnant des résultats optimaux.En raison de la faible densité énergétique du supercondensateur, sa consommation équivalente d'hydrogène est négligée dans la plupart des références bibliographiques, ce qui va non seulement à l'encontre de l'objectif de minimiser la consommation totale d'hydrogène, mais accroît également la complexité du système EMS en raison du besoin d'un système EMS supplémentaire pour calculer la demande en puissance du supercondensateur. Ainsi, une stratégie ECMS à programmation quadratique séquentielle (SECMS) est proposée pour prendre en compte le coût énergétique des trois sources d’énergie dans la fonction objectif. Une stratégie de contrôle basée sur des règles (RBCS) et une stratégie hybride (HEOS) a été également conçues pour être comparée à SECMS. La dégradation des sources d'énergie représente un défi majeur pour la stabilité du système SECMS développé. Basé sur l'estimation en ligne de l'état de santé de la pile à combustible et de la batterie, le système ECMS adaptatif (AECMS) a été implémenté en ajustant le facteur équivalent et le taux de changement dynamique de la pile à combustible. Les résultats de la simulation montrent que l’AECMS peut assurer le maintien de la charge de la batterie et l’augmentation de la durabilité de la pile à combustible.Pour valider les algorithmes de gestion de l'énergie et les modèles numériques proposés, un banc d'essai expérimental a été construit autour de l'interface temps réel DSPACE. La comparaison des résultats de la simulation numérique et des résultats expérimentaux a montré que le système SECMS proposé fonctionne à un rendement maximal, que le supercondensateur fournit la puissance de pointe et que la batterie fonctionne comme un tampon d’énergie. Il a été prouvé que la négligence de la consommation d'hydrogène équivalente au supercondensateur dans l'ECMS conduit à un fonctionnement non optimal. Comparé à RBCS et HEOS, la SECMS a le moins d'hydrogène consommé et le courant de pile à combustible le plus stableGlobal warming, environment pollution and exhaustion of petroleum energies have risen their attention of the humanity over the world. Fuel cell hybrid electric vehicle (FCHEV) taking hydrogen as fuel and have zero emission, is thought by public and private organisms as one of the best ways to solve these problems. This PhD dissertation consider a FCHEV with three power sources: fuel cell, battery and supercapacitor, which increases the difficult to design an energy management strategy (EMS) to split the power between the different power sources.Among the EMS available in the current literature, the Equivalent consumption minimization strategy (ECMS) was selected because it allows a local optimization without rely on prior knowledge of driving condition while giving optimal results.Due to low energy density of supercapacitor, its equivalent hydrogen consumption is neglected in most bibliographic references, which not only counter to the aim of minimizing whole hydrogen consumption but also increase the complication of EMS due to the need of an additional EMS to calculate supercapacitor power demand. Thus, a sequential quadratic programming ECMS (SECMS) strategy is proposed to consider energy cost of all three power sources into the objective function. A rule based control strategy (RBCS) and hybrid strategy (HEOS) are also designed in order to to be compared with SECMS. Degradation of energy sources represents a major challenge for the stability of the developed SECMS system. So, based on online estimating state of heath of fuel cell and battery, an adaptive ECMS (AECMS) has been designed through adjusting the equivalent factor and dynamical change rate of fuel cell. The simulation results show that the AECMS can ensure the charge sustenance of battery and the increase of fuel cell durability.To validate the proposed energy management algorithms and the numerical models an exerimental test bench has been built around the real time interface DSPACE. The comparison of the simulation and experimental results showed that the proposed SECMS is operated at around maximum efficiency, supercapacitor supplies peak power, battery works as the energy buffer. It has been proved that the neglect of supercapacitor equivalent hydrogen consumption in ECMS leads to not optimal operation. Compared with RBCS and HEOS, SECMS has least hydrogen consumption and most stable fuel cell current
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Juma, Calestous. "Evolutionary technological change : the case of fuel ethanol in developing countries." Thesis, University of Sussex, 1986. http://sro.sussex.ac.uk/id/eprint/79463/.
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This study suggests an evolutionary approach to the analysis of energy technology policy. The approach emphasizes economic fluctuations, technological change and Institutional re-organization through time. The liquid fuel sub-sectors of Zimbabwe and Kenya constitute different technological systems adapted to the production and utilization of different energy forms. They represent different market niches In a techno-economic landscape. Gasoline occupies a central role In the energy budget. The 1973-74 oil crisis created major fluctuations which made it possible to introduce fuel ethanol as an alternative liquid fuel. The process of realising the ethanol niche was largely dependent on the existence of technological options whose technical and financial characteristics allowed them to compete favourably with conventional 1iquid fuels. Niche realization also required the modification of the adoptive terrain to reduce the obstacles to the introduction of the new technological systems. The entire process takes an evolutionary perspective because it involves the generation. selection and retention of technological options under constantly changing conditions. Moreover. the technological systems continue to undergo or require incremental Improvements after they have been installed. Such improvements require the generation of plant-level technical knowledge and often lead to the accumulation of local technological capacity. A glance at the evolutionary path reveals periods of gradual change. punctuated by moments of increased innovations which are often linked to periods of major fluctuations. The process is associated with a complex network of institutional arrangements which are also re-organized either in response to fluctuations or in anticipation of emerging niche opportunities. Institutions play a central role because the process is not random, it is purposive and based on socio-economic expectations. It is precisely this point that led to major differences In the process of niche realization In Zimbabwe and Kenya. although both countries were presented with the same technological options. The study draws a wide range of technology policy and research implications from these differences.
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Schneider, Kenneth. "Photo-microbial fuel cells." Thesis, University of Bath, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675704.
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Fundamental studies for the improvement of photo-microbial fuel cells (pMFCs) within this work comprised investigations into ceramic electrodes, toxicity of metal-organic frameworks (MOFs) and hot-pressing of air-cathode materials. A novel type of macroporous electrode was fabricated from the conductive ceramic Ti2AlC. Reticulated electrode shapes were achieved by employing the replica ceramic processing method on polyurethane foam templates. Cyclic voltammetry of these ceramics indicated that the application of potentials larger than 0.5 V with regard to a Ag/AgCl reference electrode results in the surface passivation of the electrode. Ti2AlC remained conductive and sensitive to redox processes even after electrochemical maximisation of the surface passivation, which was shown electrochemically and with four terminal sensing. Application of macroporous Ti2AlC ceramic electrodes in pMFCs with green algae and cyanobacteria resulted in higher power densities than achieved with conventional pMFC electrode materials, despite the larger surface area of the Ti2AlC ceramic. The effect of electrode surface roughness and hydrophobicity on pMFC power generation and on cell adhesion was examined using atomic force and confocal microscopy, contact angle measurements and long-term pMFC experiments. The high surface roughness and fractured structure of Ti2AlC ceramic was beneficial for cell adhesion and resulted in higher pMFC power densities than achieved with materials such as reticulated vitrified carbon foam, fluorine doped tin oxide coated glass or indium tin oxide coated plastic. Toxicity of the MOF MIL101 and its amine-modified version MIL-101(Cr)-NH2 on green algae and cyanobacteria was assessed on the basis of both growth in liquid culture and by exclusion zones of agar colonies around MOF pellets. MOF MIL101 was found harmless in concentrations up to 480 mg L-1 and MIL-101(Cr)-NH2 did not exhibit toxic effects at a concentration of 167 mg L-1. Air-cathodes were produced from a range of carbon materials and ion-exchange membranes. Hot-pressing of Zorflex Activated Carbon Cloth FM10 with the proton-selective Nafion® 115 membrane provided the best bonding quality and pMFC performance.
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Zhou, Yu. "Energy Harvesting Using a Thermoelectric Generator and Generic Rule-based Energy Management." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1196802707.
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Chen, Dayi. "Nickel-based anodic electrocatalysts for fuel cells and water splitting." Thesis, The University of Utah, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10157943.
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Our world is facing an energy crisis, so people are trying to harvest and utilize energy more efficiently. One of the promising ways to harvest energy is via solar water splitting to convert solar energy to chemical energy stored in hydrogen. Another of the options to utilize energy more efficiently is to use fuel cells as power sources instead of combustion engines. Catalysts are needed to reduce the energy barriers of the reactions happening at the electrode surfaces of the water-splitting cells and fuel cells. Nickel-based catalysts happen to be important nonprecious electrocatalysts for both of the anodic reactions in alkaline media. In alcohol fuel cells, nickel-based catalysts catalyze alcohol oxidation. In water splitting cells, they catalyze water oxidation, i.e., oxygen evolution. The two reactions occur in a similar potential range when catalyzed by nickel-based catalysts. Higher output current density, lower oxidation potential, and complete substrate oxidation are preferred for the anode in the applications.
In this dissertation, the catalytic properties of nickel-based electrocatalysts in alkaline medium for fuel oxidation and oxygen evolution are explored. By changing the nickel precursor solubility, nickel complex nanoparticles with tunable sizes on electrode surfaces were synthesized. Higher methanol oxidation current density is achieved with smaller nickel complex nanoparticles. DNA aggregates were used as a polymer scaffold to load nickel ion centers and thus can oxidize methanol completely at a potential about 0.1 V lower than simple nickel electrodes, and the methanol oxidation pathway is changed. Nickel-based catalysts also have electrocatalytic activity towards a wide range of substrates. Experiments show that methanol, ethanol, glycerol and glucose can be deeply oxidized and carbon-carbon bonds can be broken during the oxidation. However, when comparing methanol oxidation reaction to oxygen evolution reaction catalyzed by current nickel-based catalysts, methanol oxidation suffers from high overpotential and catalyst poisoning by high concentration of substrates, so current nickel-based catalysts are more suitable to be used as oxygen evolution catalysts. A photoanode design that applies nickel oxides to a semiconductor that is incorporated with surface-plasmonic metal electrodes to do solar water oxidation with visible light is proposed.
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Raji, Atanda Kamoru. "Modelling and development of fuel cell off grid power converter system." Thesis, [S.l. : s.n.], 2008. http://dk.cput.ac.za/cgi/viewcontent.cgi?article=1039&context=td_cput.
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Troughton, Gavin L. "Anodes for the direct methanol fuel cell." Thesis, University of Newcastle Upon Tyne, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335195.
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Saunders, Gary J. "Reactions of hydrocarbons in zirconia fuel cells." Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288890.
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Zhang, Taoju. "Possibilities of Alternative Vehicle Fuels : a literature review." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-19896.
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Historically, gasoline and diesel have been used as vehicle fuels for a long time. But the decline of oil supply and unstable oil price drive people to find alternative energy for vehicle fuel. Alternative energy solutions may shift energy consumption to less carbon, less pollutions and provide more energy diversity. These issues are investigated in the present literature review. The first part of the thesis introduces different kinds of alternative energy for vehicles, such as biofuel, natural gas, hydrogen, liquefied petrol gas, electricity and compressed air. The presentations includes their utilization, production, environment effect, running performance, fuel property, market share, running and investigate cost and production barriers. The second part of the thesis work compares the properties of the alternative fuels and discusses the advantages and drawbacks of different types of fuel energies. Compared with traditional fuels, alternative fuels have superiority in environment impact, sustainability and energy efficiency. Some of them have been used in reality and show a potential as future fuels. The author found that natural gas and liquefied petrol gas have low running costs, better environment performance and acceptable running range, and thus are able to substitute conventional fuels in the short term. Biofuel has better sustainability than gasoline. It will probably become more sustainable and cost effective in the mid-term period. Electricity can also become a future fuel in mid-term period since it has excellent emission performance and low running costs. Hydrogen is expected to substitute conversional fuels in the long term due to high investment costs and current unsustainable production pathway of the latter. The compressed air turned out not suitable for substituting conventional fuels because of poor efficiency and running range performance.
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Still, Michael Joseph. "All-air moisture and energy recovery system for fuel cell exhaust." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17051.
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Lott, Tawney. "A political economy analysis of liquid fuel production incentives in South Africa." Master's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/27233.
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The purpose of this study is to analyse the development of South Africa's liquid fuels industry from 1930s to the present and the various ways in which the state has extended subsidies and other measures of support to liquid fuels producers. The nature and extent of government support to the South African liquid fuels industry has remained hidden for many years, due to the veil of secrecy surrounding the industry prior to the country's transition to democracy. The study expands past analyses to identify and estimate the magnitude of subsidies to liquid fuels production in South Africa in the present. Using the historical institutional approach, the study then places these measures of support in the South African political economy environment so as to understand the institutional barriers to their reform. In doing so, the study sheds light on the drivers informing the endurance of the liquid fuels subsidy regime and state support to the liquid fuels industry following the transition to democracy.
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Psofogiannakis, George. "A mathematical model for a direct propane phosphoric acid fuel cell." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26424.
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In direct hydrocarbon fuel cells, a hydrocarbon fuel is oxidised in the anode electrode. This thesis presents a mathematical model to predict the performance of a unit cell that utilises propane as the fuel, oxygen as the oxidant, phosphoric acid as the electrolyte, and platinum as the catalyst, supported on porous carbon electrodes. The phenomena considered include the electrochemical reactions of propane oxidation and oxygen reduction on platinum, the diffusion of the gases in gas-filled electrode pores, the dissolution and diffusion of dissolved gases in liquid-filled electrode pores as well as ionic conduction of protons. The model was based on the multi-layered physical structure of a modern unit fuel cell.
The model was first applied to a phosphoric acid fuel cell cathode electrode.
Subsequently, the model was applied to a direct propane-oxygen cell. (Abstract shortened by UMI.)
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Wang, Yan. "Effects of fuel cost uncertainty on optimal energy flows in U.S." [Ames, Iowa : Iowa State University], 2007.
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