Examination of the Sooting Tendency of Three-Ring Aromatic Hydrocarbons and Their Saturated Counterparts     
Published by (Energy & Fuels)
Authors: Barrientos, Eduardo; Boehman, Andre.  Published June 01, 2010

Hydrotreating of a 1:1 blend of coal-derived refined chemical oil (RCO), with petroleum-derived light cycle oil (LCO), has been identified as a strategy for the production of an advanced coal-based jet fuel, JP-900. The conversion of the jet fuel section of a conventional refinery for the production of coal-based JP-900 would impact the quantity and quality of the other refinery products, such as diesel. The physical and chemical properties of refinery streams may be perturbed by the introduction of coal components into the refinery, including the sooting tendency. A coal-derived diesel cut was chemically analyzed via gas chromatography−mass spectrometry (GC−MS). The results showed that two- and three-ring aromatics and their hydrogenated derivatives comprised the bulk of the cut. Phenanthrene and its hydrogenated derivatives were chosen as representative compounds of this cut. Existing sooting tendency correlations and soot formation indicators in the literature apply to some two-ring aromatic compounds, but little or no information is available about how to predict the sooting tendency of aromatics with three or more rings. The present study provides an analysis of the effects of three-ring aromatic hydrocarbons on soot formation and evaluated how their saturated counterparts contribute to the reduction of the sooting tendency. This research also generated a consistent set of data for smoke point and threshold sooting index (TSI), a parameter proposed for evaluating the onset of soot formation, for three-ring compounds, which have not been reported previously. It was found that the sooting tendency of aromatics is more accurately estimated by investigating their effect on hydrocarbon mixtures rather than as pure compounds. When adding aromatic compounds with the same number of carbon atoms to a reference mixture of 35% (v/v) toluene and 65% (v/v) n-heptane, the most saturated compounds showed the lowest sooting tendency. At small concentrations, three-ring saturated hydrocarbons in fuel blends did not improve the sooting tendency, in contrast to two-ring saturated compounds, which are good hydrogen donors and have low sooting tendency. Finally, the calculated TSI of the mixtures was used to estimate the TSI and smoke points of the individual three-ring compounds contained in the blend using mixing rules.

Estimation of Opacity Tendency of Ethanol- and Biodiesel-Diesel Blends by Means of the Smoke Point T     
Published by (Energy & Fuels)
Authors: Armas, Octavio; Gomez, Arantzazu; Barrientos, Eduardo; Boehman, A..  Published July 01, 2011

Oxygenated fuels in diesel engines represent an alternative to conventional petroleum-derived fuel to achieve current European emissions standards (EURO 5), especially with regard to particulate matter (PM), where the reduction of the limit in mass concentration is 80% compared to that for the previous EURO 4 standard. Among these oxygenated fuels, biodiesel- and ethanol-diesel blends have great potential in reducing smoke opacity and, therefore, the particulate matter emitted. The smoke point is a technique used for determining the sooting tendency of kerosene and aviation fuels and it can be used as an indicator of smoke opacity. The smoke point technique can also be used with an extensive variety of fuels including automotive diesel fuels. This work proposes a new methodology for estimating the decrease in diesel engine exhaust opacity when different ethanol- and biodiesel-diesel blends are used instead of conventional diesel fuels. Different binary biodiesel- diesel and ethanol-diesel blends were tested in a smoke point lamp together with ternary ethanol-biodiesel-diesel blends. The results of binary blends were compared to the opacity obtained in a light duty diesel engine operating in a steady state mode confirming that the molecular weight to smoke point ratio accurately reproduces the decreasing trend in opacity, when normalized to a conventional diesel fuel, as a function of the percentage of biodiesel or ethanol in the blend. Moreover, the new proposed methodology showed how not only the oxygen content but also its functional group plays an important role in this decreasing opacity trend. In this way, tests of ternary ethanol-biodiesel-diesel blends on a smoke point lamp could predict the trend in smoke opacity when a diesel engine is fuelled with them.

Design, Development and Validation of the 2013 Penn State University E85 Series Plug-In Hybrid Vehicle     
Published by (SAE International)
Authors: Barrientos, Eduardo; Grigoryan, Aram; Neal, Gary; Shepley, Luke.  Published September 09, 2012

The Pennsylvania State University Advanced Vehicle Team (PSU AVT) is one of the fifteen (15) participating teams at the EcoCAR 2 “Plugging In to the Future” challenge. The team has worked in the design, development and validation of converting a 2013 Chevrolet Malibu, into an advanced technology hybrid vehicle. The PSU AVT has determined that a Plug-In Series Electric Hybrid architecture best meets the design goals of the EcoCAR 2 competition. The vehicle will utilize a front-wheel drivetrain powered by a Magna E-drive; an Auxiliary Power Unit (APU) based on a naturally aspirated Weber MPE 750 engine, converted for use with E85, coupled to a UQM PowerPhase 75 generator; an Energy Storage System (ESS) based on six A123, 15s3p battery modules; and a Mototron ECM-5554-112-0904 controller as the Master Vehicle Controller (MVC). This paper will present the details of the proposed architecture, including the selection. process and validation as well as future engineering considerations in order to implement the design into the vehicle.

Effects of Oxygenates Molecular Structure on the Sooting Tendency and PM Emissions of Ethanol-Gasoli     
Published by (Proceedings of the IMECE 2012 )
Authors: Barrientos, Eduardo; Boehman, Andre; Neal, Gary; Haworth, Daniel.  Published November 01, 2012

Fuel composition has a significant effect in emissions from particulate matter (PM) and soot formation in internal combustion engines. Numerous studies, both experimental and numerical, have reported that oxygenated fuels reduce particulate emissions. These studies have proved that this reduction depends not only on the oxygen content but also on the molecular structure and the different oxygen functional groups. Consequently, this paper contains an analysis of the relationship between fuel composition and soot formation and PM emissions from oxygenated fuel blends. In this study, ethanol-gasoline and biodiesel-diesel fuel blends have been tested via a smoke point lamp in order to determine the variations in the sooting tendency in relation to the oxygen content of fuel blends and the effect of oxygenated additives on the sooting propensity of the blends. Particulate matter collected from the smoke point tests has been analyzed via X-Ray Photoelectron Spectroscopy (XPS) to quantify the surface oxygen content of the soot samples and to qualitatively identify oxygen functionalities on the samples. An attempt was made to correlate these results with the oxygen concentrations and molecular structure of the fuels.

Group additivity in soot formation for the example of C-5 oxygenated     
Published by (Combustion and Flame)
Authors: Barrientos, E.; Lapuerta, M.; Boehman, A..  Published May 23, 2013

Sooting tendencies have been measured for 29 compounds with 5 carbon atoms and different oxygen contents, along with 12 additional oxygenated pure compounds and 10 blends of commercial fuels. The test compounds include alcohols, ethers, aldehydes, ketones, acids, esters, keto-esters and hydroxy-esters. The Threshold Sooting Index (TSI), as defined and used in the literature, was primarily used to quantify the sooting tendency of the compounds. It is shown that this index does not account for the presence of oxygen atoms in the fuel molecules, and the impact of fuel oxygen on the stoichiometric air requirement. The application of TSI to oxygenated fuels leads to sooting tendencies inconsistent with those reported in the literature. A new sooting index is proposed for oxygenated and non-oxygenated compounds, which considers the relation between the height of the flame tip and the volumetric stoichiometric air requirement of the flame. This new index is denoted as the Oxygen Extended Sooting Index (OESI). The results obtained by this new index corroborate that not only the oxygen content but also the molecular structure has an influence on the sooting tendency of fuels. Different functional groups, not only those including oxygen atoms, impart different sooting tendencies. A structural group contribution approach based on group additivity is proposed to interpret experimental observations on the effect of oxygen functional groups on the sooting tendency of fuels using the example of C-5 oxygenated fuels. Groups with a higher fraction of carbon–carbon bonds showed a higher contribution to the sooting tendency than those with a higher concentration of carbon–hydrogen bonds. Among the C-5 mono-oxygenated compounds, the sooting tendency increased in this order: aldehydes < alcohols < ketones < ethers < n-alkanes and for the C-5 di-oxygenated compounds, the sooting tendency order was: acids < esters < di-ethers. In general, both unsaturated and branched compounds showed slight increases in sooting tendency with respect to their saturated and linear counterparts. Finally, the new sooting index was applied to commercial biofuel blends (denatured ethanol–gasoline and soybeanderived biodiesel–diesel) and empirical correlations were obtained.

Impact of Ester Structures on the Soot Characteristics and Soot Oxidative Reactivity of Biodiesel     
Published by (SAE)
Authors: • Barrientos, E.; Maricq, M.; Anderson, J.; Boehman, A. .  Published April 01, 2015