Understanding the impact of cavitation on hydrocarbons in the middle distillate range
AffiliationShell Global Solution ; Shell Global Solution ; University of Chester ; University of Chester
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AbstractHydrocarbons in the middle distillate range (C8 - C26) have been treated with ultrasound at 20 kHz - a frequency sufficient to drive acoustic cavitation. The high temperatures experienced as a result of the implosion of fuel vapour bubbles are sufficient to produce pyrolytic degradation and dehydrogenation, as well as a growth mechanism that results in the formation of small particles that have similarities with the primary soot particles produced during diesel combustion. These nanosized particles agglomerate as a result of kinetically driven collisions during cavitation to form a dispersion of micron sized particles in the treated hydrocarbon. The particles are carbonaceous in character, being a mixture of amorphous and graphitic-like carbon. The mass of material produced increases with the C/H atomic ratio of the hydrocarbon undergoing cavitation and is decreased through the addition (1 - 3 %v/v) of low boiling paraffinic hydrocarbons, possibly as a result of lowering the temperature developed inside imploding cavities. Dispersions of microparticles contain equilibrated levels of nanoparticles. If sufficiently high numbers of these smaller primary particles are present they agglomerate due to thermally driven collisions during post-cavitation storage. When this happened a sharp rise in the number of 1 - 2 µm particles was seen after only a few days. Some evidence is presented for the behaviour of ultrasonically treated hydrocarbons being related to the degradation of diesel fuel exposed to hydrodynamic cavitation in the fuel systems of modern common rail direct injection diesel engines.
CitationUnderstanding the impact of cavitation on hydrocarbons in the middle distillate range, Fuel, 2015, 156, pp. 30-39
DescriptionNOTICE: this is the author’s version of a work that was accepted for publication in Fuel. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Fuel, 156, September 2015, pp. 30-39, http://dx/doi.org/10.1016/j.fuel.2015.04.026
SponsorsShell Global Solutions
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