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Dissertations / Theses on the topic 'Fuel additives'

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Published: 4 June 2021
Last updated: 6 February 2022

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1

Webb, Oliver A. "Bespoke container molecules for fuel additives." Thesis, University of Surrey, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606795.

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The findings of the first reported guest centric encapsulation study are presented within. The guests were of interest as petrol and diesel (fuel) additives, with the focus on 2-ethylhexyl nitrate (2-EHN), di-tert-butyl peroxide (DTBP), aniline, N-methylaniline (NMA) and N,Ndimethylaniline CNNDMA). Complexation with 2-EHN and DTBP was achieved with the novel calix[4]arene derivative, 5, 11, 17, 23-tetra-tert-butyl, 25, 27-bis(oxyethylphenylurea), 26, 28-dihydroxycalix[4}arene, CA(III). This was confirmed in solution by the use of NMR techniques. The multi-step procedure to yield a tetrol cavitand. with recent updates to the procedures are fully described. A new carceplex system with aniline encapsulated, carceplex aniline (4, 24- 5,5'- 6,10- 11 , 11'- 12, 16- 17, 17'- 18, 22- 23, 23'- 4', 24'- 6',10'- 12', 16'- 18 ',22' dodecamethylenedioxy, 2, 8, 14,20, 2', 8' ,14', 20'-octapentyl-bis-calix[4]arene aniline) was produced in a pioneering pressure tube encapsulation follwing unsuccessful attempts under reflux conditions. A pyrogallol[4]arene with pentyl pendant group (2, 8, 14, 20-tetrapentylpyrogallol[4]arene) PA(I) was synthesised and successfully employed for self-assembled complex formation with aniline, NMA and NNDMA. These complexes were found to be stable in polar and apolar media at 313 K over a duration of 2 months. The complexes were of stoichiometry 10:1 (aniline: PA(I)), 12:1 (NMA : PA(I)), and 4:1 (NNDMA: PA(l)). Significant variation was observed when complexes were analysed by TGA in air up to 800 °C compared to control. PA(I) . aniline and PA(I) . NMA displayed solubilities in apolar media making them suitable for analysis in test engines as fuel additives. The first report of a (two-step) carcerand synthesised from pyrogallol[4]arene, PA(I) with the introduction of methylene dioxy spanning and bridging groups, yielding the novel carcerand 4,24- 5, 4'.- 6, 5' - 10, 1\ ' - 12, 16- 17, 16'- 18, 17'- 22, 23'- 23, 24' - 6', 10'- 18', 22' dodecamethylenedioxy, 2, 8, 14, 20, 2', 8', 14', 20' -octapentyl-bis-calix[4]arene is also presented.
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2

Higgins, Clare Louise. "Novel dendritic fuel and lubricant additives." Thesis, University of Reading, 2016. http://centaur.reading.ac.uk/65944/.

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Oxidation processes have a detrimental effect on hydrocarbon based materials such as fuels, lubricants, polymers and foodstuffs. Antioxidants are known to interrupt oxidation processes by predominantly reacting with radical species. The development of such stabilisers is discussed in Chapter 1. The use of dendritic architectures in antioxidant development is a relatively 'young’ area of research. This unique class of macromolecule consists of a well-defined, branched structure which can potentially bear a high loading of antioxidant under an excellent degree of structural control. Dendritic architectures are the focus of this thesis and Chapter 2 discusses the synthesis of a series of antioxidant functionalised polyester dendrons via the growth of the AB2 monomer bis(MPA). The intention was to provide a high degree of sterically hindered phenolic end groups for enhanced oxidative stabilisation properties in addition to good solubility within a hydrocarbon matrix and good thermal stability with a resistance to volatilisation at high temperatures. It was revealed that these new branched antioxidants provided superior thermal and oxidative stability properties in comparison to the small molecule antioxidants currently used in the industry. Alternative functional core monomers were also investigated in Chapter 3. The functionalisation of glycerol and triethanolamine (TREN) with antioxidant moieties plus solubilising alkyl chains to yield a series of first generation polyester antioxidants is discussed. Once again, superior thermal and oxidative properties were revealed in comparison to the current industry antioxidants Irganox L135 and Irganox L57. The incorporation of a diphenylamine derivative into the same branching unit as the hindered phenol was investigated in Chapter 4 with the aim of targeting synergistic antioxidant properties. Excellent oxidative stabilities were observed, when compared to a 1:1 blend of Irganox L135 and Irganox L57, whereby an impressive 52% increase in oxidation induction time was observed. The enhanced stabilities were attributed to interesting structure-activity relationships from which it was concluded that the close contact of both amine and phenol functionalities was key in accessing improved antioxidant capabilities. A radical scavenging assay was investigated in Chapter 5 with the aim to understand structure-activity relationships of new sterically hindered phenolic antioxidants. It was revealed that complex mechanistic pathways, in addition to solvent effects, limited the use of this assay. Therefore, further refinement of this potentially time-saving spectroscopic assay is required in order to render it usable in fuel and lubricant development.
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3

Momeni, Matin. "Adsorption of fuel additives on metal surfaces." Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=201933.

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4

Young, Gregory. "Metallic nanoparticles as fuel additives in airbreathing combustion." College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7710.

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Thesis (Ph. D.) -- University of Maryland, College Park, 2007.
Thesis research directed by: Dept. of Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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5

Duboc, B. "The effect of fuel additives on diesel fuel delivery system and combustion performance." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1455626/.

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The thesis presents an investigation of several aspects of fuel additive performance, including the effects of additives on the pump torque required to deliver high pressure fuel to engine injectors, the fuel droplet size distribution at sub-zero diesel fuel temperature, when wax formation occurs, and the ignition delay of diesel fuel combustion in an engine as well as constant volume combustion vessel. Exhaust emissions due to fuel additives were also investigated in an engine. A pump torque rig was designed and commissioned to investigate fuel additive performance at various pump speeds, fuel delivery (common rail) pressures and fuel temperatures, including sub-zero temperatures at which fuel waxing occurs. An existing constant volume combustion vessel was adapted to allow observations of fuel spray with additives and it was used for spray and combustion investigations. Various components of the combustion vessel were modified to support the fuel spray instrumentation. Also, a sub-zero fuel temperature system was developed to allow fuel to be cooled down for investigations; finally, a fuel pressure intensifier was designed which allowed ease of dismantling and thorough cleaning so as to eliminate additive cross-contamination between successive tests with additives. Results have shown that in general, additives have very small effects on many aspects of the fuel delivery system performance when the primary purpose of the additive is not related to the fuel delivery system. That is, there are virtually no side effects on pumping system performance from additives not intended to affect this system. This is mainly due to the small quantity in which the fuel additives are added, which is too small to affect any of the overall fuel properties. Additionally, it was proven that a constant volume combustion vessel is unsuitable to carry out combustion performance tests on fuel with additives, due to the high error in test repeatability. In contrast, the engine tests were able to reveal the effects of several combustion modifying additives on engine combustion performance and exhaust emissions. The fuel spray analysis at sub-zero temperatures revealed that wax formation was not the likely cause of an increase in droplet size but, instead, the likely cause is an increase in fuel viscosity.
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6

Anghel, Valeria. "A study of engine fuel efficiency and oiliness additives." Thesis, Imperial College London, 1998. http://hdl.handle.net/10044/1/8937.

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7

Mägi, M. "Effect of gasoline fuel additives on combustion and engine performance." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1462024/.

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Ever increasing emissions regulations and demand for fuel economy have brought about great advances in fuel and engine technologies. Improving engine efficiency through the use of fuel additives has been practiced for nearly a century but advances to direct injection gasoline engines have presented new obstacles that need to be overcome. With direct injection systems often suffering from reduced timescales allowed for combustion processes, atomisation and vaporisation characteristics have become of paramount significance. Present study aimed at adding to the field of knowledge by experimentally investigating commercial fuel additives of different functional iti es against their effects on fuel atomisation and combustion characteristics. Fuel atomisation was evaluated through the use of a laser diffraction system and measurement of fuel viscosity and surface tension. Additives from six functional groups were investigated. Additionally, effects of anti-knock and ignition promoting additives on gasoline combustion behaviour were studied in a constant volume combustion vessel and a single cylinder research engine. Flame speed, heat release rate and emissions output were compared for three commercially available combustion improvers. Investigation into the effect of fuel additives on the physical properties and therefore on fuel atomisation and sprays revealed that in commercially employed quantities, no significant change in recorded Sauter Mean Diameter could be observed. Combustion investigations in a combustion vessel demonstrated that the low temperature reactions initiated by ignition promoting additive reduced CO emissions up to 37.7 % which could be attributed to possible reduced flame quenching near combustion chamber walls. However, in high quantities this reduction in CO levels was not experienced. Addition of anti-knock additives resulted in increased NOx emissions, which was thought to result from increased combustion durations. Present work has clarified fuel additive function and interactions with combustion processes and has demonstrated that gasoline fuel additives do not interfere with combustion processes outside their intended functionality.
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8

Lewis, John. "Mechanism of action of overbased additives in hydrocarbon media." Thesis, University of East Anglia, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280936.

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9

Clague, Nicholas Paul. "Determination of the core structure of overbased calixarenes used as detergent additives in marine fuels." Thesis, University of Hull, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310215.

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10

Lague, Christian M. "Waste vegetable oil as a diesel fuel extender." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26712.

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The possibility of using waste vegetable oil from deep-frying processes as a fuel for long term use in diesel engines was investigated. Research was aimed at using existing technology in terms of engine design in order to utilize a maximum amount of waste vegetable oil as the energy source with a minimum of processing. A small swirl-chamber diesel engine was selected and used to run the 200-hour test recommended by the EMA for testing vegetable oil-based fuels. A blend of 20/80 (waste oil/diesel fuel) was tested as well as a 50/50 blend. BSFC data for both blends did not indicate any significant deterioration in engine performance during the 200 hour tests for ail the fuels tested. However, the 50/50 blend BSFC data had more spread than the data from the 20/80 or the diesel baseline test. This was attributed to variable amounts of deposits on the injector nozzle throughout this test Carbon deposits on all other parts of the combustion chamber were comparable for all the fuels tested. Wear of the engine parts was also comparable except for the piston rings. Piston ring wear was greater with diesel fuel and smaller when burning the 50/50 blend. This was attributed to a film of unburned fuel on the cylinder wall that improved lubrication. Lower -lubricating oil consumption was also attributed to this film. The alternate fuel blends completed the 200 hour EMA screening test and could be considered as possible candidates for long-term use in I.D.I, engines.
Applied Science, Faculty of
Graduate
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11

Rawson, Paul Stansfield Christy-Anne. "Field method for detection of metal deactivator additive in jet fuel." Fishermans Bend, Victoria : Defence Science and Technology Organisation, 2009. http://nla.gov.au/nla.arc-24592.

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12

Hatchett, Susan Elizabeth. "Development of techniques for the analysis of additives in aviation turbine fuel." Thesis, University of Portsmouth, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292302.

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13

Smith, Carole-Anne. "The synthesis of some new polymeric materials as potential additives for diesel fuel." Thesis, Durham University, 1993. http://etheses.dur.ac.uk/2214/.

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Wax crystal formation in diesel and related hydrocarbon fuels during cold weather is a long standing problem. Current polymeric additives to diesel fuel modify the crystal habit of the wax, in a variety of ways, to improve its performance at low temperature. These wax crystal modifiers (WCM) have to operate at low concentrations (0.01-0.1%) to make their use economical, so it is critical that their structures are optimised for the application. The objectives of this work was to synthesise, characterise and test some new polymeric additives which are anticipated to effect the crystallisation of the wax from the fuel and to prepare a model ethylene vinyl acetate (EVA) polymer to gain insights into the mode of action of the EVA co-polymers which are currently in use as WCM. Ring opening metathesis polymerisation was chosen as the method of preparation for these new polymeric additives. An introduction to wax crystallisation in diesel fuel and some proposals for the preparation of these new polymeric additives are given in Chapter 1. Chapter 2 discusses olefin metathesis and ring opening metathesis polymerisation reactions. The synthesis and characterisation of monomers and polymers are given in Chapters 3 and 4 respectively. Results from fuel tests are described in Chapter 5.
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14

Goh, Allen Yong Lian. "Influence of alcohol fuel additives on strain measurements in glass fiber-reinforced micro-specimens." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0006/MQ59807.pdf.

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15

Kozak, Darby Merrick. "The adsorption and stabilising effect of fuel additives on carbon black and steel surfaces." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420903.

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16

Chia, Chung Lim. "Classical and ReaxFF molecular dynamics simulations of fuel additives at the solid-fluid interface." Thesis, University of Manchester, 2019. https://www.research.manchester.ac.uk/portal/en/theses/classical-and-reaxff-molecular-dynamics-simulations-of-fuel-additives-at-the-solidfluid-interface(a1a5cb5d-3283-4ebc-9ef1-b44aac16821b).html.

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In the automotive industry, a kind of fuel additives, known as surfactant, is used to protect metallic surfaces. Its efficiency strongly depends on factors such as temperature, solvent properties and the presence of other surfactants in the system. In this thesis, both classical and ReaxFF molecular dynamics (MD) simulations are used in studying the impacts of these factors on the adsorption of organic surfactants at the fluid-solid interface. Firstly, a classical MD simulation study of competitive adsorption is carried out on a multi-functional phenol and amine surfactant model with ethanol at the oil/iron oxide interface. As the concentration of ethanol increases, the ethanol molecules effectively compete for the adsorption sites on the iron oxide surface. This observation concurs with the experimental findings of similar oil/iron oxide systems. Unlike most MD interfacial studies, ReaxFF MD uses a fully flexible and polarizable solid surface. The second part of the thesis includes a study on the effect of polarity of organic molecules on the structure of iron oxide using ReaxFF-based MD simulations. The simulation results suggest that care must be taken when parameterising empirical and transferable force fields because the fixed charges on a solid slab may not be a perfect representation of the real system, especially when the solid is in contact with polar compounds. Lastly, but not the least, missing ReaxFF interaction parameters for Fe/N have been developed to simulate the adsorption of amine based surfactant on iron oxide. The parameterisation of the force field is done by fitting these interaction parameters to a set of quantum mechanical data involving iron-based clusters. These newly developed parameters are able to capture chemisorption and proton transfer between hexadecylamine and iron oxide.
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17

Prentice, Giles Michael Derek. "Understanding and utilising π-π interactions in hydrocarbons : towards advanced lubricants and fuel additives." Thesis, University of Bath, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.707584.

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Aromatic interactions in a non-porous solvents have been significantly overlooked in the past few decades. In contrast aromatic interactions in polar solvents, in particular water have been studied extensively leading to an in depth understanding of these interactions and driving forces in these media. The first chapter of this thesis reviews the nature of aromatic interactions, how to best define and evaluate their strength, as well as presenting a historical perspective on aromatic interactions in non-polar environments. The second chapter of this thesis describes the strength and driving forces of aromatic interactions in such solvents as heptane, methylcyclohexane, dibutyl ether, squalene and chloroform. This was evaluated by studying an archetypal aromatic donor-acceptor complex between that of naphthalenediimide and dialkoxynaphthalene. A combination of 1H NMR, UV-vis spectroscopy and isothermal calorimetry techniques were employed to elucidate their strength and thermodynamic functions. In the third and fourth chapters the knowledge acquired concerning aromatic interactions in non-polar environments was then employed in the design of lubricant additives. In Chapter 3, as potential friction modifiers in which their behaviour on metal surfaces was probed using reflective absorbance infrared spectroscopy, sum frequency generation spectroscopy, as well as initial rig tests. Finally in chapter 4, as potential soot solubilisation agents in which the interaction of various polycyclic aromatics with perylenediimide was monitored by UV-vis spectroscopy.
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18

Nuszkowski, John. "The effects of fuel additives on diesel engine emissions during steady state and transient operation." Morgantown, W. Va. : [West Virginia University Libraries], 2008. http://hdl.handle.net/10450/5809.

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Thesis (Ph. D.)--West Virginia University, 2008.
Title from document title page. Document formatted into pages; contains xviii, 144 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 106-113).
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19

Ghamari, Mohsen. "An experimental examination of combustion of isolated liquid fuel droplets with polymeric and nanoparticle additives." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/5758.

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In spite of recent attention to renewable sources of energy, liquid hydrocarbon fuels are still the main source of energy for industrial and transportation systems. Manufactures and consumers are consistently looking for ways to optimize the efficiency of fuel combustion in terms of cost, emissions and consumer safety. In this regard, increasing burning rate of liquid fuels has been of special interest in both industrial and transportation systems. Recent studies have shown that adding combustible nano-particles could have promising effects on improving combustion performance of liquid fuels. Combustible nano-particles could enhance radiative and conductive heat transfer and also mixing within the droplet. Polymeric additive have also shown promising effect on improving fire safety by suppressing spreading behavior and splatter formation in case of crash scenario. Polymers are also known to have higher burning rate than regular hydrocarbon fuels. Therefore adding polymeric additive could have the potential to increase the burning rate. In this work, combustion dynamics of liquid fuel droplets with both polymeric and nanoparticle additives is studied in normal gravity. High speed photography is employed and the effect of additive concentration on droplet burning rate, burning time, extinction and soot morphology is investigated. Polymer added fuel was found to have a volatility controlled combustion with four distinct regimes. The first three zones are associated with combustion of base fuel while the polymer burns last and after a heating zone because of its higher boiling point. Polymer addition reduces the burning rate of the base fuel in the first zone by means of increasing viscosity and results in nucleate boiling and increased burning rates in the second and third stages. Overall, polymer addition resulted in a higher burning rate and shorter burning time in most of the scenarios. Colloidal suspensions of carbon-based nanomaterials in liquid fuels were also tested at different particle loadings. It was found that dispersing nanoparticles results in higher burning rate by means of enhanced radiative heat absorption and thermal conductivity. An optimum particle loading was found for each particle type at which the maximum burning rate was achieved. It was observed that the burning rate again starts to reduce after this optimum point most likely due to the formation of large aggregates that reduce thermal conductivity and suppress the diffusion of species.
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Papachristos, Miltiades. "Influence of structure and other characteristics of substitute fuel components in petrol on engine efficiency and pollution." Thesis, University of Sheffield, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264616.

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21

Sowa, John M. "Studies of Coal Nitrogen Release Chemistry for Oxyfuel Combustion and Chemical Additives." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd3294.pdf.

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22

Sharifi, Monir [Verfasser]. "Functionalisation of mesoporous materials for application as additives in high temperature PEM fuel cell membranes / Monir Sharifi." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2012. http://d-nb.info/1022810324/34.

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23

Patel, P. "Development of an optical facility for an investigation into the effect of fuel additives on diesel sprays." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1398386/.

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Environmental legislation has pressured fuel and automotive industries to alter their technologies for compliance. Changes made to a fuel to achieve compliance can push specific fuel qualities, such as lubricity, to a level away from that required by the automotive engine, creating a fuel/engine requirement gap. Use of fuel additives offer an economical route to bridge the gap, however, their effects on stages of the diesel combustion process is not yet fully understood owing to measurement difficulty. Greater understanding of additive effects requires precision control of operational test conditions with the ability to apply high fidelity measurement techniques. To enable this a high pressure, high temperature optical facility was developed which allows for the acquisition of large data-sets of spray parameters for a more accurate study of the effect fuel additives have on the diesel combustion process. For facility commissioning, tests on diesel fuel sprays into elevated pressure and temperature environments were carried out, with data obtained from high speed backlight illuminated imaging. Macroscopic spray measurements such as penetration length and spreading areas of the sprays were performed, so that effects of ambient pressure and temperature on these parameters could be identified and discussed. From the tests, injector opening times were a main cause of variability in the observed characteristics which were taken into account in the study. Following commissioning, a systematic study was carried out using combustion improving and detergent additives for the first time, where low and high concentrations were tested. Similar behaviours in penetration lengths for each of the additives tested were seen, however no statistical confidence could be applied to the observation as the penetration lengths of the additised fuels for the tested back pressures, since these values did not shift from the base fuels' measured data by a magnitude greater than the experimental error. Penetrating spray area data variance was large, and changes due to additives were unidentifiable. To further clarify, laser droplet sizing was employed at atmospheric conditions to identify whether additives cause changes in microscopic measurements of the spray. The tests showed no change in the droplets' Sauter Mean Diameters (SMD) were observed due to additives. The study carried out clearly indicates that the additives added in the tested concentrations did not change the statistically determined transient parameters of diesel sprays.
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24

Jones, Matthew. "Ignition and Combustion Characteristics of Nanoscale Metal and Metal Oxide Additives in Biofuel (Ethanol) and Hydrocarbons." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1304469906.

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25

Soares, Helena Sofia Marques Pinto. "Electrolytes for ceramic oxide fuel cells." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15883.

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Doutoramento em Nanociências e Nanotecnologia
The main objective of this dissertation is the development and processing of novel ionic conducting ceramic materials for use as electrolytes in proton or oxide-ion conducting solid oxide fuel cells. The research aims to develop new processing routes and/or materials offering superior electrochemical behavior, based on nanometric ceramic oxide powders prepared by mechanochemical processes. Protonic ceramic fuel cells (PCFCs) require electrolyte materials with high proton conductivity at intermediate temperatures, 500-700ºC, such as reported for perovskite zirconate oxides containing alkaline earth metal cations. In the current work, BaZrO3 containing 15 mol% of Y (BZY) was chosen as the base material for further study. Despite offering high bulk proton conductivity the widespread application of this material is limited by its poor sinterability and grain growth. Thus, minor additions of oxides of zinc, phosphorous and boron were studied as possible sintering additives. The introduction of ZnO can produce substantially enhanced densification, compared to the un-doped material, lowering the sintering temperature from 1600ºC to 1300ºC. Thus, the current work discusses the best solid solution mechanism to accommodate this sintering additive. Maximum proton conductivity was shown to be obtained in materials where the Zn additive is intentionally adopted into the base perovskite composition. P2O5 additions were shown to be less effective as a sintering additive. The presence of P2O5 was shown to impair grain growth, despite improving densification of BZY for intermediate concentrations in the range 4 – 8 mol%. Interreaction of BZY with P was also shown to have a highly detrimental effect on its electrical transport properties, decreasing both bulk and grain boundary conductivities. The densification behavior of H3BO3 added BaZrO3 (BZO) shows boron to be a very effective sintering aid. Nonetheless, in the yttrium containing analogue, BaZr0.85Y0.15O3- (BZY) the densification behavior with boron additives was shown to be less successful, yielding impaired levels of densification compared to the plain BZY. This phenomenon was shown to be related to the undesirable formation of barium borate compositions of high melting temperatures. In the last section of the work, the emerging oxide-ion conducting materials, (Ba,Sr)GeO3 doped with K, were studied. Work assessed if these materials could be formed by mechanochemical process and the role of the ionic radius of the alkaline earth metal cation on the crystallographic structure, compositional homogeneity and ionic transport. An abrupt jump in oxide-ion conductivity was shown on increasing operation temperature in both the Sr and Ba analogues.
O principal objetivo deste trabalho é o desenvolvimento e processamento de novos materiais cerâmicos protónicos e iónicos para utilizar como eletrólito das células de combustível de óxidos sólidos (PCFCs e SOFCs, respetivamente). Com este estudo pretende-se, então, desenvolver novas formas de processamento e/ou materiais que apresentem características eletroquímicas atrativas, à base de óxidos cerâmicos nanométricos de pós preparados por processos mecanoquímicos. Existem alguns requisitos que devem ser tidos em conta de forma a garantir a máxima eficiência das PCFCs, destacando-se a elevada condutividade protónica do eletrólito aquando da operação numa gama de temperaturas intermédias, 500-700ºC. Os materiais do tipo “perovskite” foram apresentados como potenciais candidatos a incorporar o eletrólito das PCFCs, sendo o BaZrO3 dopado com 15 mol% de ítrio (BZY) o material base escolhido neste trabalho. Apesar da sua conhecida elevada condutividade protónica, estes materiais apresentam algumas limitações, tais como a fraca sinterabilidade e crescimento de grão. De forma a ultrapassar esta dificuldade, foram adicionadas pequenas quantidades de óxidos de zinco, fósforo e boro que foram estudados como possíveis aditivos de sinterização. A adição de ZnO mostrou melhorias significativas na densificação quando comparado com o material não modificado (BZY), permitindo ainda reduzir a temperatura de sinterização de 1600ºC para 1300ºC. Neste trabalho estudou-se, também, qual o melhor mecanismo de solução sólida para a adição deste aditivo, tendo-se obtido a máxima condutividade protónica nos materiais em que o Zn é intencionalmente introduzido na composição de base de “perovskite”. O P2O5 mostrou ser menos efetivo como aditivo de sinterização. A sua presença foi bastante prejudicial no crescimento de grão, apesar dos elevados níveis de densificação obtidos quando adicionado em quantidades entre 4 e 8 mol%. Porém, a utilização de fósforo mostrou também ser dramática no transporte elétrico, diminuindo a condutividade não só no interior do grão (“bulk”) como nas suas fronteiras. Já a adição de H3BO3 ao BaZrO3 (BZO) mostrou-se muito efetiva para a sinterização deste componente. Contudo, quando adicionado ao sistema dopado com ítria (BaZr0.85Y0.15O3-, BZY), o comportamento é diferente, produzindo níveis deficientes de densificação quando comparado com o BZY puro. Este fenómeno ocorre devido à formação de fases secundárias de borato de bário, cujas temperaturas de fusão são bastante elevadas. Na última parte deste trabalho foi estudado um novo material com condutividade iónica de iões óxido, o (Ba,Sr)GeO3 dopado com K. Neste estudo pretendia-se, não só avaliar a possibilidade de preparar estes pós com recurso a processos mecanoquímicos, como também estudar o papel da variação do raio iónico do catião metálico alcalino-terroso no transporte iónico, homogeneidade composicional e estrutura cristalina. Verificou-se que este material apresenta uma alteração significativa na condutividade iónica com o aumento da temperatura de operação em ambas as composições (Ba e Sr).
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Kaczmarek, Dennis [Verfasser], and Tina [Akademischer Betreuer] Kasper. "The effect of carbon-based additives on the fuel-rich conversion of methane / Dennis Kaczmarek ; Betreuer: Tina Kasper." Duisburg, 2021. http://d-nb.info/1232175994/34.

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27

Kraemer, Nathan A. "Development and qualification of a specialized gas turbine test stand to research the potential benefits of nanocatalyst fuel additives." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Dec%5FKraemer.pdf.

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Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, December 2007.
Thesis Advisor(s): Sinibaldi, Jose O. "December 2007." Description based on title screen as viewed on January 22, 2008. Includes bibliographical references (p. 69). Also available in print.
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Tanugula, Shravan Kumar [Verfasser], and Henning [Akademischer Betreuer] Hopf. "Synthesis of Glycerol Based Fuel Additives to Reduce NOx Emissions from Diesel Engines Operated on Diesel and Biodiesel fuels by SNCR / Shravan Kumar Tanugula ; Betreuer: Henning Hopf." Braunschweig : Technische Universität Braunschweig, 2010. http://d-nb.info/1175826847/34.

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Silva, Evandro Jose da. "Equilibrio liquido-liquido em misturas de hidrocarbonetos + alcoois : comportamento de fases e desenvolvimento de aditivos para aumentar a miscibilidade em misturas oleo diesel + etanol." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249600.

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Orientador: Watson Loh
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
Made available in DSpace on 2018-08-04T14:51:58Z (GMT). No. of bitstreams: 1 Silva_EvandroJoseda_D.pdf: 11483730 bytes, checksum: 3a27a58fb8b0765831e47f169a14e5d5 (MD5) Previous issue date: 2005
Doutorado
Físico-Química
Doutor em Quimica
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Obytová, Eliška. "Vliv používání aditiv do paliva u osobních vozidel." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-446751.

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This diploma thesis deals with the addition of automotive fuels and their effects. The aim was to evaluate the function and efficiency of fuel additives present in the fuel at gas stations, and subsequently to improve the fuels accordingly by adding additional individual chemical compounds. The theoretical part explains the concepts, functions and processes related to fuel additives and the basics of tribotechnology. The practical part deals with the process of testing the properties of fuels, their functions, additional additives and its impact for practical use.
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Martinez, Aguilar Maricelly. "Production de biobutanol à partir de lignocellulose : un nouveau procédé thermochimique A simple process for the production of fuel additives using residual lignocellulosic biomass Production of fuel additives by direct conversion of softwood bark using a cheap metal salt Conversion of lignocellulosic biomass in biobutanol by a novel thermal process." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2020. http://www.theses.fr/2020EMAC0006.

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La demande d'énergie au cours des dernières années a augmenté et un grand pourcentage de l'énergie est dérivée des combustibles fossiles, mais l'utilisation de ces carburants a généré des émissions de CO2 et de la pollution environnementale. Pour ce problème, on a mené des recherches sur l'utilisation des énergies alternatives à partir de biomasse lignocellulosique pour produire des carburants qui réduisent les émissions de CO2. Le Canada est un pays avec une abondance de résidus lignocellulosiques qui sont une source pour la production de différents produits chimiques. La première partie de l’étude se concentre sur l’étude cinétique de la production du lévulinate de méthyle et de l’acide lévulinique à partir de la cellulose avec un catalyseur homogène (H2SO4). La deuxième partie porte sur la conversion de la cellulose en lévulinates (molécule plateforme) en utilisant un catalyseur homogène (H2SO4) et un catalyseur solide (Al2(SO4)3). La troisième partie se consacre sur l’étude de l’hydrolyse du lévulinate de méthyle en acide lévulinique en utilisant des catalyseurs à base de cuivre. Des techniques d’analyse tels que le SEM, XRD, TPX ont été utilisés pour étudier les catalyseurs supportés et comprendre leur effet sur la réaction. La quatrième partie du projet porte sur l’étude des résultats obtenus des différentes réactions réalisées pour la production du 2-butanol à partir de la biomasse lignocellulosique en passant par la production du lévulinate de méthyle et de l’acide lévulinique qui sont des molécules plateforme et potentiellement substitutes au biodiesel. Par la suite, l’acide lévulinique est décarboxylé en 2-butanone et le dernier est réduit en 2-butanol en utilisant des catalyseurs bifonctionnels (tels que le Ru / C et le Pt / C) en conditions douces. L’ensemble de ces travaux contribuent à la compréhension des réactions du nouveau procédé de production du butanol
In the last years, the energy demand has increased and a large pourcentage of this energy is obtained from fossil fuels, but the use of these fuels has generated CO2 emissions and environmental pollution. For this reason, this research was focused on the use of alternative energies from lignocellulosic biomass to produce renewal fuels decreasing CO2 gas emissions. Canada is a country with high quantities of lignocellulosic biomass which can represent a cheap source for the high value added molecules and fuels production. The first part of the study focuses on the kinetic study of the production of methyl levulinate and levulinic acid from cellulose with a homogeneous catalyst (H2SO4). The second part study the conversion of cellulose to levulinates (platform molecule) using a homogeneous catalyst and a heterogeneous catalyst (Al2(SO4)3). The third part is devoted to study the hydrolysis of methyl levulinate to levulinic acid using copper-based catalysts. Analytical techniques such as SEM, XRD, TPX were used to study the supported catalysts and understand their effect on the reaction. The fourth part of the project relates to the study of the production of 2-butanol from lignocellulosic biomass through the production of methyl levulinate and levulinic acid which are platform molecules and potentially substitutes for biodiesel. Thereafter, the levulinic acid is decarboxylated to 2-butanone and the latter is reduced to 2-butanol using bifunctional catalysts (such as Ru/C and Pt/C) under mild conditions. All of this work contributes to understanding the reactions of the new butanol production process
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Woortman, Dirk Volker [Verfasser], Thomas B. [Akademischer Betreuer] Brück, Thomas B. [Gutachter] Brück, and Michael [Gutachter] Rychlik. "The production of microalgae derived, functional additives for jet fuel, food and cosmetics / Dirk Volker Woortman ; Gutachter: Thomas B. Brück, Michael Rychlik ; Betreuer: Thomas B. Brück." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/121147643X/34.

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Bergius, William Nigel Adam. "Synthesis of well defined, linear-dendritic, end-functionalised poly N-vinyl pyrrolidone additives via reversible addition-fragmentation transfer polymerisation for use in polymer electrolyte membrane fuel cells." Thesis, Durham University, 2012. http://etheses.dur.ac.uk/3594/.

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An ongoing challenge in polymer science is the preparation of materials with specific surface properties that differ from the bulk, whilst retaining the advantageous mechanical properties of the bulk polymer. We have explored the use of multi-end functionalised polymer additives, which undergo rapid spontaneous adsorption to a surface or interface, as an efficient method of modifying surface properties. These materials are of potential use in tailoring the hydrophobicity of the gas diffusion layer (GDL) in a polymer electrolyte membrane fuel cell (PEMFC), and hence optimising fuel cell efficiency. In this research, reversible addition-fragmentation transfer (RAFT) polymerisation has been used to synthesise a range of well-defined, low molecular weight, end-functionalised poly N-vinyl pyrrolidone (PVP) polymer additives bearing aryl-ether end groups containing up to three, low surface energy, C8F17 fluoroalkyl chains. Polymer end-functionality is introduced via the design of functionalised RAFT chain transfer agents (CTAs). Three novel CTAs have been made in addition to their corresponding end-functionalised PVP additives, in a range of molecular weights. Thin films have been prepared comprised of polymer blends of unfunctionalised PVP and varying percentages of each end-functionalised PVP additive, and these films have been analysed by contact angle measurements, ion beam analysis and atomic force microscopy in order to investigate effects of additive concentration, additive molecular weight, matrix molecular weight, design of functional group and annealing. We have shown that modest amounts of additive (<2.5%) can render the surfaces of bulk PVP hydrophobic and lipophobic.
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Pennisi, Vanessa. "Contribution à l'identification et à l'évaluation d'un combustible UO2 dopé à potentiel oxygène maîtrisé." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0191/document.

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La température et la pression partielle d’oxygène (PO2) constituent les paramètres majeurs contrôlantles évolutions thermochimiques en réacteur des combustibles nucléaires de type oxyde, et notammentla spéciation des produits de fission potentiellement corrosifs (Cs, I, Te). Pour limiter les risques derupture de la gaine en Zr par corrosion, une solution innovante consiste à imposer au combustible defonctionner dans un domaine de PO2 où les espèces chimiques des gaz de fission sont inoffensives, pardopage in-situ avec un tampon oxydo-réducteur solide. Le niobium, avec ses couples redoxNbO2/NbO et Nb2O5/NbO2, a été identifié comme le candidat le plus prometteur. Un procédé defabrication d’un combustible dopé niobium répondant à cet objectif et conforme aux spécificationsd’usage (densité, microstructure) a été optimisé. L’étude expérimentale du système UO2-NbOx a révélél’existence à 810°C d’une phase liquide entre UO2 et NbO2, non identifiée à ce jour. La caractérisationdes phases solides et en solution du niobium nous a conduit à proposer un modèle thermodynamiquede solubilité du dopant dans UO2 à 1700°C. Une étude approfondie de la spéciation du niobiumprécipité a permis d’identifier la présence simultanée dans le matériau des phases majeures NbO2 etNbO, ainsi que Nb en moindre teneur. La coexistence du niobium sous deux degrés d’oxydationdifférents constitue un élément-clé de démonstration d’un possible effet tampon in-situ, dont l’impactest observé sur certaines propriétés du combustible dépendantes de la PO2, la densification notamment.Les résultats confirment le potentiel prometteur des combustibles tamponnés en PO2 au regard de sesperformances en réacteur
Temperature and oxygen partial pressure (PO2) of nuclear oxide fuels are the main parametersgoverning both their thermochemical evolution in reactor and the speciation of volatile fissionproducts such as Cs, I or Te. An innovative way to limit the risk of cladding rupture by corrosionunder irradiation consists in buffering the oxygen partial pressure of the fuel under operation in a PO2domain where the fission gas are harmless towards Zr clad, by using solid redox buffers as additives.Niobium, with its NbO2/NbO and Nb2O5/NbO2 redox couples has been found to be a promisingcandidate to this end. A manufacturing process of a buffered UO2 fuel, doped with niobium has beenoptimized, in order to fulfill usual specifications (density, microstructure). The experimental study ofthe UO2-NbOx system has shown the existence of a liquid phase between UO2 and NbOx at 810°C,which was not reported in the literature. The characterization of Nb containing phases present in UO2both in solid solution and as precipitates has lead us to propose a solubility thermodynamic model ofniobium in UO2 at 1700°C. An extensive study of the niobium precipitates shows the co-existence inthe fuel of NbO2 and NbO as major phases, together with small amounts of metallic Nb. The coexistenceof niobium under two oxidation states inside the fuel is a key element of demonstration of apossible in-situ buffering effect, which is likely to impact some properties of the material that aredependent upon PO2, such as densification. These results confirm the promising potential of oxygenbuffered fuels as regard to their performance in reactor
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35

Brown, Dustin Heath. "Design of a Fuel Additive Production Facility." Thesis, The University of Arizona, 2011. http://hdl.handle.net/10150/144249.

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36

Taylor, Kevin Brian. "Comparative Study of Alternative Fuel Icing Inhibitor Additive Properties and Chemical Analysis of Metal Speciation in Aviation Fuels." University of Dayton / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1280850044.

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37

Le, Minh Duy. "L’étude de l’influence de la structure chimique des additifs sur le contrôle de la réactivité des carburants." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0065.

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Les sociétés modernes ont besoin de moteurs à combustion interne plus propres et plus efficaces. Cette contrainte entraîne une évolution significative des systèmes de combustion et de la formulation de carburants. L’adéquation moteur-carburant est l’élément clé à optimiser pour atteindre cet objectif. Parmi les paramètres en jeu, la réactivité du carburant est une caractéristique de premier ordre. C’est l’une des raisons en lien avec l’utilisation des additifs. Ils permettent au carburant d’améliorer l’ensemble de ses propriétés notamment vis-à-vis de la combustion. Cependant, le choix et l’utilisation des additifs se heurte encore à un manque de compréhension de leur mécanisme d’action. Dans ce contexte, cette thèse vise à mieux comprendre l’effet chimique des additifs sur la réactivité dans la phase gazeuse. Trois additifs, dont un booster de cétane, un booster d’octane et un antioxydant sont considérés : le 2-ethylhexyl nitrate (EHN), le ferrocène et le 2,4 xylénol respectivement. L’effet chimique de ces additifs sur la réactivité d’un carburant modèle contenant 35 % de n-heptane et 65 % de toluène en volume a fait l’objet d’une étude expérimentale et numérique. Des expériences ont été menées à l’aide de trois équipements : un tube de choc, une machine de compression rapide et un brûleur à flamme plate. L’utilisation de ces équipements permet d’explorer la variation de la réactivité dans des conditions variables représentatives du fonctionnement des moteurs. En parallèle, un modèle cinétique détaillé a été élaboré en s’appuyant sur des données récentes de la littérature. L’accord satisfaisant entre les expériences et les simulations permet de proposer des hypothèses quant à l’effet chimique des additifs
Modern societies require cleaner and more efficient internal combustion engines. This constraint has involved a significant evolution in the combustion systems and fuel formulation. Engine-fuel adequacy is the key item to be optimized to achieve this goal. Among adjustable parameters, the reactivity of the fuel is the most important characteristic to be considered. This leads to an increasing use of additives that allows fuel to meet various combustion requirements. However, the design and the use of additives still faces a lack of comprehension regarding their effect. In this context, this thesis aims to better understand the chemical effect of additives on the fuel gas-phase reactivity. Three additives including a cetane booster, an octane booster, and a free radical scavenger are considered: 2-ethylhexyl nitrate, ferrocene, and 2,4-xylenol, respectively. The chemical effect of these additives on the reactivity of a surrogate fuel containing 35% n-heptane and 65% toluene by volume was experimentally and numerically investigated. Experiments were conducted in three devices: a shock tube, a rapid compression machine, and a heat flux burner. The use of these experimental devices allows to explore the reactivity over a wide range of engine-relevant conditions. For simulations, a detailed kinetic model was developed based on recent literature data. The satisfactory agreement between experiments and simulations enables to propose several hypothesis regarding the chemical effect of the additives
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Merkley, Stephen L. "Effects of Radiation Heating on Additively Printed Hybrid Fuel Grain Oxidizer-to-fuel Ratio Shift." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5230.

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This thesis examined the hypothesis that radiative heat transfer in small-scale printed-fuel hybrid rocket motors is responsible for the observed decreasing oxidizer-to-fuel (O/F) ratio shift. The magnitude of the radiation term was negligible for the motor sizes and types of propellants that have been previously tested, but was reintroduced in this study. To prove this hypothesis, a detailed enthalpy balance model was developed and tested using experimental fuel regression rate data obtained from a variety of motor scales using additively-manufactured acrylonitrile butadiene styrene (ABS) fuel grains.
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Chiu, Chuang-Wei. "Biodiesel synthesis and impact of cold flow additives /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1421124.

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40

Saanum, Inge. "Experimental Studies of Hydrogen as a Fuel Additive in Internal Combustion Engines." Doctoral thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1978.

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Combustion of hydrocarbons in internal combustion engines results in emissions that can be harmful both to human health and to the environment. Although the engine technology is improving, the emissions of NOx, PM and UHC are still challenging. Besides, the overall consumption of fossil fuel and hence the emissions of CO2 are increasing because of the increasing number of vehicles. This has lead to a focus on finding alternative fuels and alternative technologies that may result in lower emissions of harmful gases and lower CO2 emissions. This thesis treats various topics that are relevant when using blends of fuels in different internal combustion engine technologies, with a particular focus on using hydrogen as a fuel additive. The topics addressed are especially the ones that impact the environment, such as emissions of harmful gases and thermal efficiency (fuel consumption). The thesis is based on experimental work performed at four different test rigs:

1. A dynamic combustion rig with optical access to the combustion chamber where spark ignited premixed combustion could be studied by means of a Schlieren optical setup and a high speed video camera.

2. A spark ignition natural gas engine rig with an optional exhaust gas recycling system.

3. A 1-cylinder diesel engine prepared for homogeneous charge compression ignition combustion.

4. A 6-cylinder standard diesel engine

The engine rigs were equipped with cylinder pressure sensors, engine dynamometers, exhaust gas analyzers etc. to enable analyses of the effects of different fuels. The effect of hydrogen blended with methane and natural gas in spark ignited premixed combustion was investigated in the dynamic combustion rig and in a natural gas engine. In the dynamic combustion rig, the effect of hydrogen added to methane on the flame speed and the flame structure was investigated at elevated pressure and temperature. A considerable increase in the flame speed was observed when adding 30 vol% hydrogen to the methane, but 5 vol% hydrogen also resulted in a noticeable increase. The flame structure was also influenced by the hydrogen addition as the flame front had a higher tendency to become wrinkled or cellular. The effect is believed to mainly be caused by a reduction in the effective Lewis number of the mixture. In the gas engine experiments, the effect of adding 25 vol% hydrogen to natural gas was investigated when the engine was run on lean air/fuel mixtures and on stoichiometric mixtures with exhaust gas recirculation. The hydrogen addition was found to extend the lean limit of stable combustion and hence caused lower NOx emissions. The brake thermal efficiency increased with the hydrogen addition, both for the fuel lean and the stoichiometric mixtures with exhaust gas recirculation. This is mainly because of shorter combustion durations when the hydrogen mixture was used, leading to thermodynamically improved cycles.

Two types of experiments were performed in compression ignition engines. First, homogenous charge compression ignition (HCCI) experiments were performed in a single cylinder engine fueled with natural gas and diesel oil. As HCCI engines have high thermal efficiency and low NOx and PM emissions it may be more favorable to use natural gas in HCCI engines than in spark ignition engines. The mixture of natural gas, diesel oil and air was partly premixed before combustion. The natural gas/diesel ratio was used to control the ignition timing as the fuels have very different ignition properties. The natural gas was also replaced by a 20 vol% hydrogen/natural gas mixture to study the effect of hydrogen on the ignition and combustion process. Also, rape seed methyl ester (RME) was tested instead of the diesel oil. The combustion phasing was found to mainly be controlled by the amount of liquid fuel injected. The presence or absence of hydrogen resulted in only marginal changes on the combustion. Because the diesel oil and RME have much lower autoignition temperatures than both hydrogen and natural gas, the properties of the liquid fuel may overshadow the effect of the hydrogen addition. A large difference however, was found between the RME and the diesel oil with the necessity to inject much more RME than diesel oil to obtain the same combustion phasing.

The last experiments with compression ignition were performed by using a standard Scania diesel engine where the possibilities to reduce particulate matter (PM) and other emissions by introduction of combustible gas to the inlet air (named fumigation) were investigated. Hydrogen, methane and propane were introduced at different rates replacing up to 40% of the total fuel energy. Also, a biodiesel consisting of mainly RME was tested instead of the diesel oil. Because of the low density of hydrogen gas, less of the fuel energy could be replaced by hydrogen than by the two other gases. Higher rates of hydrogen would sacrifice the safety by exceeding the lower flammability limit in the inlet air. Only moderate reductions in PM were achieved at high gas rates, and because of the limitation in the practical achievable hydrogen rate it was not possible to obtain considerable reductions in PM emission by hydrogen addition. The NOx emissions were found to be little influenced by the fumigation, but the THC emissions strongly increased with increased methane and propane rates, especially at a low engine load. Propane fumigation resulted in considerably less THC emissions than methane fumigation. The biodiesel resulted in higher PM emissions than the diesel fuel at low load, but was considerably lower at the higher loads. This is believed to be because of the low volatility of the biodiesel which may lead to emissions of un-burned fuel at low load when the temperature is low. At higher loads this is believed to be less of a problem because the temperature is higher, and the oxygen content of biodiesel is believed to increase the PM oxidation and/or reduce the formation of PM.

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Faramarzi, Simin. "Effect of Alternative Fuels on SCR Chemistry." Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146185.

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In the time line of world industrial age, the most important era begins in the late 18th century when the use of fossil fuels was growing intensively. This approach has continued and developed up to the 20th century. Besides, this trend has had side effects like polluting environment. Air pollution is one of the critical issues nowadays that stems from using hydrocarbon fuels. One type of the problematic compounds in polluting air is nitrogen oxides that can be produced in combustion process from engines and industrial plants. Different solutions have been suggested to remove air polluting compounds. One method for removing nitrogen oxides is using the mechanism of Selective Catalytic Reduction in silencer of engines. This method has become practical in trucks’ engines. Therefore, research on SCR chemistry is important for improving the usage of this method in removing nitrogen oxides. SCR has its own problems when used in trucks. One of the problems is formation of white clumps on pipe wall of silencers using SCR which can cause back pressure in the engines and costs a lot to remove them from engines.  This report evaluates the effect of alternative fuels on SCR chemistry .Different parameters affecting deposit formation are studied and evaluated. Ethanol is one of the controversial fuels used in engines and acetic acid is one its byproducts. Also, urea and its by products are important materials in SCR chemistry, too. Consequently, the first part of the report studies the influence of acetic acid and Ferrite steel, one of the usual steels in silencers of engines, on urea, biuret and cyanuric acid decomposition. The instruments used in the first part include TGA-DSC (Thermo Gravimetric Analysis-Differential Scanning Calorimetric) which is connected to FTIR (Fourier Transform Infrared Spectroscopy).In the second part of the report, the effect of diesel exhaust and ethanol exhaust on cyanuric acid evaporation rate is evaluated. Cyanuric acid is the main compound forming deposit in silencers. The instrument used in the second part is TGA. The third part consists surveying effect of Adblue, aqueous solution of urea, and additivised Adblue, surfactant added Adblue to improve its efficiency, in a patented rig that is scaled down of a silencer of truck. The most important result for the first part includes the effect of Ferrite steel treated with acetic acid that accelerated the decomposition of cyanuric acid. This result can be investigated more in order to be used in silencers to accelerate the decomposition rate of clumps formed. In the second part, it is found out that cyanuric acid evaporates faster under ethanol exhaust than diesel exhaust. The third part’s results shows that in the current assembly of pipes in the rig, Additivised Adblue loses its improved efficiency which is an interesting result for engine welding in order to avoid this type of connection in engines.
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Johnsson, Elin. "Investigation of tribological mechanisms of a boron additive in lubricants and fuel enhancer." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-258234.

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The effect of using a boric acid based additive in lubricants and fuel enhancers was investigated in this study. Experiments were performed in a reciprocating and a continuous sliding ball-on-disk test equipment. Different oil types and temperatures were used. The aim of the experiments was to provide information about how these boron containing lubricants work in terms of chemistry and tribology. The surfaces after tribological contact were analyzed with Light Optical Microscopy (LOM), Vertical Scanning Interferometry (VSI), Scanning Electron Spectroscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Secondary Ion Mass Spectroscopy (SIMS). The boric acid based additive and the temperature used affected both the friction and wear. A higher oil temperature resulted in wider wear tracks. Oil with boron additive seemed to lower the friction coefficient at temperatures above 50 °C, compared to the same oil without boric acid; the reference oil. The tests also indicated that friction coefficients as low as 0.05 can be achieved by using a boron additive layer on the disk surface together with PAO-oil. Tribofilms containing Zn, P, S, Mg and O were formed in the wear tracks at high temperatures for both the reference oil and oil with boron additive. Oxidized regions were found in the tracks created from tests at 25 °C. Tests with oil containing boron additive resulted in lower Zn concentrations in the tracks, which is an indication that the boric acid based additive hinders the formation of these Zn rich tribofilms. To summarize, both oils and fuel enhancers with boric acid can obtain lower friction coefficients compared to those without this additive. The role of boric acid in the tests performed, both regarding the tribology and chemistry, is not yet fully understood and more chemical investigations are needed.
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Sacramento, Santana Hesdras Henrique. "Improving mechanical properties and microstructure development of fiber reinforced ceramic nuclear fuel." Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/37199.

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At the present work the UO2 fuel production process was extensively studied and analyzed. The objectives of such investigation were to understand and analyze the influence of different additives and the variation of the production process steps on the microstructure and consequently in the mechanical strength of the nuclear fuel pellet. Moreover, an improvement of the qualitative characteristics of the ceramic fuel pellets was also aimed. For this purpose UO2 pellets without additives, the so-called standard pellets, pellets containing as additive for example AZB (Azodicarbonamid), black U3O8 (Oxidized uranium pellet scrap - OS), green U3O8 (Oxidized uranium powder - OP), keratin fibers (a non conventional additive) were produced. The introduction of these additives to the UO2 powder mixture prior or after the granulation production step and in different concentrations produced several microstructure configurations. As it would not be possible to analyze all of them here so during the investigation pre-tests some of them were separated to be studied in more detail. Pellets with AZB added after the granulation presented larger grains and larger pores than those with AZB added before granulation, also porosity free grains and a granulate structure instead of a homogeneous one. Pellets with OS present fine porosity distributed all over the pellet matrix with some porosity clusters whereas pellets containing OP show in its matrix porosity agglomerated in form of hooks. As for the grain size, a more uniform grain size distribution can be observed in pellets OS than in pellets with OP. The variations in the amount of keratin fibers added, sintering dwell time and green density resulted indeed in different microstructures. Nevertheless, some common characteristics among them were observed such as the presence of elongated pores, porosity clusters and larger grains located at the pellets borders while the smaller ones were concentrated more in the central part of the pellet. This distribution of grains was identified as bi-modal structure. The mentioned microstructure aspects certainly influence on the mechanical properties of the fuel pellet. However, the sintering parameters, the green and final pellet density and the pellet dimensions also have an influence on the mechanical characteristics of the pellets. For studying the influence of all these parameters on the pellet mechanical properties four testing procedures were utilized the so-called squirrel-cage where the mechanical resistance of the not sintered pellets against mechanical shocks was tested, the diametrical compression test (Brazilian Test) where the strength of sintered and not sintered pellets was studied, the Vickers indentation technique and the creep test where the pellet plasticity respectively at room and at elevated temperatures was analyzed. The squirrel-cage results showed that the pellets with keratin fibers were much more mechanically resistant than those pellets without it, which means that the keratin fibers acted, prior sintering, as a powder binder increasing the cohesion among the powder granules proportionating the green pellets higher mechanical resistance against impacts. The Brazilian test evaluated the influence of the pellet length to the pellet diameter (L/D ratio), the influence of different additives mixed to the UO2 powder and the different pellet production processes. The L/D influence analysis showed that if one fixes the pellet diameter and increase the pellet length the Weibull modulus (here a measure of the pellet lot reliability) will also increase. By comparing pellets with OS, OP and 0.3% keratin fibers it was observed that pellets with OS presented the highest volume of pores smaller than 10 mm while pellets with OP and keratin presented the highest volume of pores larger than 20 mm. It seems that this relevant characteristic favored to the highest Weibull strength value for pellets with OS. In the indentation test standard pellets, pellets with OS and pellets with keratin fibers were tested. The results showed that the calculated hardness for the standard pellets is slightly lower when compared to the values obtained by the pellets with keratin fibers. Also the pellets containing OS when compared to the keratin fibers pellets have in most of the cases a lower hardness. The calculated fracture toughness and fracture surface energy values show also a better mechanical behavior for the keratin fibre pellets than in the standard pellets. Standard pellets, pellets with 30%OP, which had the smallest grain size, pellets with keratin fibers, having the bi-modal structure and pellets with chromium oxide, which had the largest grain size, were tested in the creep furnace. The results showed that all pellets with additives presented a better creep behavior than the standard pellets. Among the pellets prepared with additives the comparison clearly showed that under lower stresses pellets with smaller grains have a better creep rate. By increasing the applied stresses we observe an improvement of the creep rate of the pellets with chromium oxide and keratin fibre even slightly overcoming the pellets with 30%OP at the highest applied stress.
Sacramento Santana, HH. (2014). Improving mechanical properties and microstructure development of fiber reinforced ceramic nuclear fuel [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/37199
TESIS
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44

Johnson, Rodney Miller David L. Cernansky N. P. "A fundamental study of the oxidation behavior of SI primary reference fuels with propionaldehyde and DTBP as an additive /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2834.

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45

Dale, James G. "Implications of the Use of Cerium Oxide Nanoparticle Diesel Fuel-Borne Catalysts: From Transformation During Combustion Through Exposure to Plants and Soils." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/77538.

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The fate of nanoparticulate cerium oxide from the diesel fuel catalyst Envirox was studied from its presence in the additive to its transformations during combustion through its exposure to plants and soils using a broad range of analytical techniques. Envirox is a fuel-borne catalyst comprised of nanoparticles of cerium oxide suspended in kerosene. The particles suspended in Envirox were confirmed by synchrotron X-ray diffraction, dynamic light scattering, and electron microscopy to be 5-7 nm crystals of CeO2 present as 15 nm aggregates. Significant changes to the particles were induced by the combustion process, resulting in 50-300 nm euhedral crystals of CeO2 in the exhaust as discovered using high resolution transmission electron microscopy. Single particle electron diffraction of the emitted cerium oxide particles showed evidence of ordered oxygen vacancies, indicative of a superstructure. Variations in the engine operating load resulted in no significant differences in the emitted cerium oxide particles. The mobility through soils and impacts on the plant Brassica napus (dwarf essex rape) of the emitted cerium oxide were compared to small and large CeO2 nanoparticles as well as diesel particulate matter emissions with very low cerium. The small CeO2 nanoparticles exhibited high mobility through soils and significant uptake and translocation in the plants. The large CeO2 nanoparticles showed extremely low mobility in soils and no significant increase in cerium anywhere in the plants. Cerium emissions from a diesel engine utilizing Envirox was found to have moderate mobility through the soils as well as an increased association with the roots of the plants, though translocation of the cerium into the aboveground biomass was not statistically significant. Despite uptake and translocation of some materials by B. napus, exposure to these cerium sources at 100 ppm Ce in the topsoil showed no significant impacts on the growth or overall health of the plants when compared to unexposed control samples. This dissertation shows that CeO2 nanoparticles employed as catalysts suspended in diesel fuel are altered during their use resulting in changes to their mobility and interaction upon entering the environment. This dissertation lays the groundwork for a new approach to nanotoxicology.
Ph. D.
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46

Fletcher, Philip James. "Determination of additives in fuels using automated flow injection analysis with chemiluminescence detection." Thesis, University of Plymouth, 2002. http://hdl.handle.net/10026.1/2068.

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The overall objective of this thesis was to develop field deployable instrumentation for the selective, sensitive determination of additives in diesel fuels using flow injection with chemiluminescence detection. The target analytes were the detergent dodecylamine and the lubricity additive P655. Chapter One describes the types of additives that are used in fully formulated diesel fuels in order to improve performance and outlines the need for robust analytical methods to be able to detect their presence / absences in fuels at the point of distribution, i.e. at the petrol pump. Flow injection (FI), and chemiluminescence (CL) are described as suitable techniques for sample preparation and detection respectively. The application of FI-CL for the quantitative determination of various analytes is reviewed, with the focus on real sample matrices. Finally the technique of solid phase extraction is discussed as a means of selective analyte preconcentration / matrix removal prior to FI-CL detection Chapter Two describes the development and optimisation (both univariate and simplex) of an FI-CL method for the determination of dodecylamine in acetonitrile / water mixtures using the catalytic effect of amines on the peroxyoxalate / sulphorhodamine 101 CL reaction. The linear range for dodecylamine was 0 - 50 mg Lˉ¹ with a detection limit of 190 µg Lˉ¹ and RSDs typically < 4 %. The effect of indigenous diesel compounds on the CL response is also investigated. Chapter Three investigates the applicability of the method developed in Chapter Two to determine dodecylamine in diesel fuels. Solid phase extraction was needed prior to analysis by FI-CL. The development of a solid phase extraction that is compatible with the FI-CL system is detailed. GC-NPD and GC-MS analysis are used in order to validate the solid phase extraction procedure. A range of diesel fuels have been spiked with an additive package containing dodecylamine and have been analysed off-line using FI-CL. Recoveries for all diesel fuels analysed were < 72 % and all fuels could by identified from the corresponding base fuel. Chapter Four describes the design and construction of a fully automated on-line solid phase extraction flow injection chemiluminescence analyser for the determination of dodecylamine in diesel fuel. Details of the automation and programming using LabVIEW are described. Results obtained using the automated on-line system are compared with results obtained using off-line SPE with FI-CL detection from Chapter Three. Recoveries for all fuels except SNV were < 71 %, and all fuels except SNV could be positively identified from the corresponding base fuels. No significant differences were found between the on-line and off-line results (within 95 % confidence limits). Chapter Five investigates the feasibility of determining the lubricity additive P655 in diesel fuel using FI-CL. The optimisation and development of a method using the competing reactions of periodate with alcohols and periodate with the CL oxidation reaction with pyrogallol is discussed, and the development of a solid phase extraction procedure for the extraction of P655 from an organic matrix is described. The limit of detection for P655 using SPE without preconcentration was 860 mg Lˉ¹ and was linear in the range 0 - 10000 mg Lˉ¹ (R² = 0.9965).
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47

Lenner, Lukas. "Engine Redesign Utilizing 3D Sand Printing Techniques Resulting in Weight and Fuel Savings." Youngstown State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1472734710.

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48

Olander, Petra. "Tribology for Greener Combustion Engines : Scuffing in Marine Engines and a Lubricating Boric Acid Fuel Additive." Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-333430.

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This thesis aims at increased knowledge in two fields of tribological research; both related to making currently used combustion engines greener. The first field regards the possibilities of using a boric acid fuel additive to increase fuel efficiency. The second field is about the severe wear phenomenon scuffing, which can become problematic when cargo ships are operated on low-sulphur fuel to reduce sulphuric emissions. Tribological tests were developed and performed to simulate the applications. Advanced surface analysis was performed to understand changes occurring on the outermost surface of sliding components, which affect friction and wear. Samples from engines were studied to verify the relation between the lab tests and the applications. In the case of boric acid, the coefficient of friction was below 0.02 for large parts of the tests, but varied with test parameters. The corresponding reduction in friction was up to 78% compared with tests without the additive. As an attempt to assess if the substantial fuel savings found in field tests with passenger cars (6%) can be explained by friction reduction in boundary and mixed lubricated parts of the piston assembly, assumptions were presented that would lead to fuel savings close to these 6%. Boric acid was detected on surfaces after the tests, and the tribofilm appearance depended on test parameters. The tribofilms were shown to be affected by storage time and test temperature; a finding that is vital for future studies. In the case of scuffing, mechanisms were studied and accumulation of wear debris had a significant role on scuffing initiation in the lab scale scuffing tests. Regarding the possibility to test materials scuffing resistance, there was a large scatter in the results, and thereby difficult to draw conclusions. Two new piston ring materials were identified to perform somewhat better than the currently used. In conclusion, findings that could facilitate immediate improvement of fuel efficiency of today’s combustion engine vehicles as well as findings that strengthen available hypotheses on scuffing mechanisms are presented. The latter offers improved understanding of scuffing and thereby give possibilities to counteract the higher risk associated with operation on cleaner fuel.
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49

Barnett, G. M. (Gordon M. ). "Feed additives and animal waste phosphorous reactions." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41322.

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Organic phosphorus (P$ sb{ rm o}$) in farm animal wastes must be mineralized to inorganic P for subsequent plant use. This study was conducted to determine if feed additives affect P$ sb{ rm o}$ mineralization, manure decomposition, and plant growth. Feed additives in aqueous systems affected the P mineralization of inositol hexaphosphate by phytase and of adenosine monophosphate by alkaline phosphatase. Pronounced effects were produced by bacitracin and both enzymes and by neomycin on phytase. Feed additives in dairy cattle (Bos taurus L.) manure produced effects on microbial activity as measured by gas production that differed from those produced on fecal phosphatase activity. Additives applied directly or with manure to Ste. Rosalie clay, Greensboro loam, or silica sand had no effect on barley (Hordeum vulgare L.) yield but did produce additive, rate, growth medium, and manure dependent effects on plant P concentration and soil phosphatase activity. Therefore, each feed additive must be independently evaluated to determine its effect on biological systems.
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50

Ström, Simon. "Boric acid as a lubricating additive in fuels and in hydraulic oils." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-356795.

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Boric acid based fuel and oil additives were investigated in this study, with the aims to gain a deeper understanding of how the boric acid fuel additive behaves, to investigate the effect of low rates of fuel additive addition and tribofilm longevity, and to investigate how boric acid behaves as a hydraulic oil additive. Fuel additive experiments were performed in a reciprocating sliding rig with a cylinder on flat contact geometry with fuel additive sprayed on the contact repeatedly, whereas the hydraulic oil experiments were performed in a reciprocating sliding rig with a ball on flat contact with the oil and additive present from the start. Analysis was performed using vertical scanning interferometry (VSI), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). The tribofilms created by the fuel additive provided excellent friction reduction capabilities, even with low or no rate of replenishment. As more additive was sprayed, wear resistance seemed to increase as the surface became increasingly covered. Film coverage need to be less than 20% of the surface in order to gain full friction reducing effects. The hydraulic oil additive had little effect on friction or wear resistance under the used parameters and no tribofilm was found.
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