Fuel compositions phase stability

Selection of the radiolysis conditions is of primary importance. If studies carried out with a pure extractant enable the intrinsic stability of the molecules to be verified, radiolysis in solution and especially in a basic medium are indispensable to guarantee the approaches good representativity, as much from the point of view of species formation as from that of their distribution (potential elimination of the shortest degradation products, the most polar to the aqueous phase). The characteristics of the irradiation source (nature, dose rate, integrated dose) and also the temperature are essential parameters. Thus, the nature of the irradiation depends on the composition of the fuel, and the dose rate is dependent on the bum-up and cooling time of the fuel, while the exposure time of a solvent depends on the implementation conditions of the proposed process (flowsheet and nature of the contactors). 

Related systems It should be noted that specific properties for applications could be enhanced by using solid solutions, doped materials, and composites, instead of pure ceria. For example, ceria-zirconia solid solution is a well known ceria based material for enhanced OSC and high ionic conductivity for solid state fuel cell components. It is also used in the three way catalysts for automobile waste gas cleaning, because of the improved thermal stability, surface area, and reducibility. The synthesis, structure, and properties of ceria-zirconia have been actively studied for a long time. Di Monte and Kaspar et al. presented feature articles on the nanostructured ceria—zirconia-mixed oxides. The studies on phase, structures, as well as the microstructures are discussed and reviewed (Di Monte et al., 2004). 

PEVD has been applied to deposit auxiliary phases (Na COj, NaNOj and Na SO ) for solid potenfiometric gaseous oxide (CO, NO, and SO ) sensors, as well as a yttria stabilized zirconia (YSZ) ceramic phase to form composite anodes for solid oxide fuel cells. In both cases, the theoretically ideal interfacial microstructures were realized. The performances of these solid state ionic devices improved significantly. Eurthermore, in order to set the foundation for future PEVD applications, a well-defined PEVD system has been studied both thermodynamically and kinetically, indicating that PEVD shows promise for a wide range of technological applications. 

Microemulsions form spontaneously and exhibit nano-disperse structures. In contrast to emulsions there is no additional energy input necessary for the production of a microemulsion. The formation is thermodynamically favoured due to the ultra-low interfacial tension between the oil and water domains. The microemulsified fuels are in principle thermodynamically stable for an unlimited period of time only the chemical stability of the single components could be a limiting factor. A further advantage of microemulsions in contrast to emulsions is the fact that the water content can be adjusted over a broad range. Therefore, the combustion process can be customised to specific needs. An important criterion for a microemulsion to be used as fuel is that the one-phase region extends over a wide temperature range (Fig. 11.4). Mixtures of ionic and non-ionic surfactants, which exhibit almost temperature-invariant phase behaviour by optimal composition, are suitable to meet these standards. 

Ketals are well compatible with hydrocarbon fuels and can raise the octane number and stabilize the phase homogeneity of composite fuels over a wide range of temperatures when combined with alcohols (Tables 1 and). 

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