Chemical kinetic and combustion characteristics of transportation fuels

Abstract

Internal combustion engines running on liquid fuels will remain the dominant prime movers for road and air transportation for decades, probably for most of this century. The world's appetite for liquid transportation fuels derived from petroleum and other fossil resources is already immense, will grow, will at some future time become economically unsustainable, and will become infeasible only in the very long term. The ongoing process of augmenting and eventually replacing petroleum-derived fuels with liquid alternative fuels must necessarily involve approaches that result in comparatively much lower net carbon cycle emissions from the transportation sector, most likely through a combination of carbon sequestration and renewable fuel production. The successful growth and establishment of a sustainable, profitable alternative fuels industry will be best facilitated by approaches that integrate alternative products into petroleum-derived fuel streams (i.e., gasolines, diesel, and jet fuels) and consider synergistic evolution of and integration with prevailing refining and liquid fuel distribution infrastructures. The emergence of low temperature combustion strategies, particularly those implementing dual fuel methods to achieve Reaction Controlled Compression Ignition (RCCI), offers the potential to significantly improve operating efficiency and reduce emissions with minimal aftertreatment. For all advanced combustion engine technologies, but especially for RCCI, a clear understanding of fuel property influences on combustion behaviors will be important to achieving projected engine performance and emissions. To achieve the benefits projected by emerging engine technologies, the properties of petroleumderived fuels themselves must be modified over time, but the effects of blending candidate alternative fuels with these conventional fuels must also be understood. Predicting the coupled physical and chemical property effects of real fuels on energy conversion system performance and emissions is a daunting problem, even for petroleum-derived real fuels, since each is composed of several hundred to thousands of individual chemical species typically belonging to one of a few organic classes (e.g., n-paraffins, isoparaffins, cyclo-paraffins, olefins, aromatics). For specific combustion applications, it is often the global combustion response to variations in the composition of fuel mixtures-inclusive of those occurring by blending petroleum-derived fuel with alternative fuel candidates-that is of interest for fuel property optimization. This paper presents an overview of tools used for evaluating and emulating combustionrelevant properties of real fuels and alternative fuel candidates. New analytical and statistical methods can provide important insights as to how the ensembles of distinct molecular structures found in a given fuel mixture contribute to the physical and chemical kinetic properties that govern its combustion in energy conversion processes. Such tools can in turn assist in screening candidate alternative f...

Evaluation of Non-volatile Particulate Matter Emission Characteristics of an Aircraft Auxiliary Power Unit with Varying Alternative Jet Fuel Blend Ratios

“…N-and isoparaffins typically dominate the class composition of all-fit-for-purpose, petroleum derived fuels [17]. Currently certified alternative jet fuels consist mostly of n-and iso-paraffinic compounds with negligible aromatic and sulfur content [18].…”

Combustion of synthetic jet fuels: Naphthenic cut and blend with a gas-to-liquid (GtL) jet fuel

“…The H/C ratio is a parameter influencing soot formation. Similar approaches have been presented in the literature [15][16][17][18] . Tables 1 and 3 show that the model fuel matches well the naphtenic cut cetane number (39.7 vs. 39.3) and its H/C ratio (1.84 vs. 1.87).…”

Applications of CFD for Process Safety

“…Despite the implementation of new methodologies to characterize and design new fuels, where molecular structures of the mixtures are studied in order to obtain a deeper and better understanding of the kinetic, physical and chemical properties that conduct the combustion in the energy conversion processes [37], it is still necessary to approach the combustion processes by simplified steps and considering only a representative mixture or selection of components (more common when fuel surrogates are involved). Regarding this last point, when studying the gasoline surrogates, several authors have proposed different representative mixtures, for example, Battin-Leclerc [38] considers a ternary mixture of iso-octane, 1-hexane and toluene; while Zhang [39] considers a mixture of 22 components.…”