Utilization of HVO Fuel Properties in a High Efficiency Combustion System: Part 2: Relationship of Soot Characteristics with its Oxidation Behavior in DPF

Bhardwaj, Om Parkash; Lüers, Bernhard; Holderbaum, Bastian; Koerfer, Thomas; Pischinger, Stefan; Honkanen, Markku

doi:10.4271/2014-01-2846

Cited by 37 publications

(18 citation statements)

References 27 publications

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“…HVO resulted in reduced eBC emissions but slightly increased PAH emissions compared to diesel at 13% intake O 2 . Reduced BC emissions have been found in several previous studies [56][57][58]. Other studies have found a slight increase in total PAH concentration for blends with HVO compared to other types of biodiesel [59] even though the HVO fuel is free of aromatics.…”

Section: Organic Aerosol and Pah Emissionsmentioning

confidence: 62%

Effect of Renewable Fuels and Intake O2 Concentration on Diesel Engine Emission Characteristics and Reactive Oxygen Species (ROS) Formation

et al. 2020

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Renewable diesel fuels have the potential to reduce net CO2 emissions, and simultaneously decrease particulate matter (PM) emissions. This study characterized engine-out PM emissions and PM-induced reactive oxygen species (ROS) formation potential. Emissions from a modern heavy-duty diesel engine without external aftertreatment devices, and fueled with petroleum diesel, hydrotreated vegetable oil (HVO) or rapeseed methyl ester (RME) biodiesel were studied. Exhaust gas recirculation (EGR) allowed us to probe the effect of air intake O2 concentration, and thereby combustion temperature, on emissions and ROS formation potential. An increasing level of EGR (decreasing O2 concentration) resulted in a general increase of equivalent black carbon (eBC) emissions and decrease of NOx emissions. At a medium level of EGR (13% intake O2), eBC emissions were reduced for HVO and RME by 30 and 54% respectively compared to petroleum diesel. In general, substantially lower emissions of polycyclic aromatic hydrocarbons (PAHs), including nitro and oxy-PAHs, were observed for RME compared to both HVO and diesel. At low-temperature combustion (LTC, O2 < 10%), CO and hydrocarbon gas emissions increased and an increased fraction of refractory organic carbon and PAHs were found in the particle phase. These altered soot properties have implications for the design of aftertreatment systems and diesel PM measurements with optical techniques. The ROS formation potential per mass of particles increased with increasing engine O2 concentration intake. We hypothesize that this is because soot surface properties evolve with the combustion temperature and become more active as the soot matures into refractory BC, and secondly as the soot surface becomes altered by surface oxidation. At 13% intake O2, the ROS-producing ability was high and of similar magnitude per mass for all fuels. When normalizing by energy output, the lowered emissions for the renewable fuels led to a reduced ROS formation potential.

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Section: Organic Aerosol and Pah Emissionsmentioning

confidence: 62%

Effect of Renewable Fuels and Intake O2 Concentration on Diesel Engine Emission Characteristics and Reactive Oxygen Species (ROS) Formation

et al. 2020

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“…An intermediate conclusion-as argued by e.g. Bhardwaj et al (2014), Lapuerta et al (2012), Vander Wal andTomasek (2003)-is that the nanostructure of the soot primary particles essentially determines their reactivity against oxidation. A simple reactivity-nanostructure relation approximately linearly correlates the mean length of the fringes in the primary particles with T max .…”

Section: Fig 10mentioning

confidence: 97%

“…To allow for a continuous operation of PF, the captured soot is removed periodically by a regeneration procedure or continuously by oxidation with residual O 2 in the exhaust gas (Fang and Lance 2004). The reaction rates of soot against oxidation by O 2 determine the frequency and efficiency of this kind of PF-regeneration (Fang and Lance 2004;Bhardwaj et al 2014). The regeneration behavior of PF depends on the reaction rates of soot particles with oxidative reactants at engine exhaust gas temperatures (573 K to approximately 1073 K).…”

Section: Introductionmentioning

confidence: 99%

“…Huang and Vander Wal (2016) demonstrated the dependence of the nanostructure of soot particles upon partial premixing and the associated changes in the gas-phase chemistry of ethylene-air Bunsen flames. The collocation of layered graphene-like structures measured by their length, separation distance and curvature as well as defects within the crystallite structure (Bhardwaj et al 2014;Lapuerta et al 2012;Vander Wal and Tomasek 2003;Pfau et al 2018) altogether affect the reactivity of soot. Reactivity of soot, therefore, is a consequence of both agglomerate morphology and the nanostructure and chemical composition of primary particles (Pfau et al 2018).…”

Section: Introductionmentioning

confidence: 99%

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Why Soot is not Alike Soot: A Molecular/Nanostructural Approach to Low Temperature Soot Oxidation

Hagen

Hardock

Koch

et al. 2020

Flow Turbulence Combust

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Due to worldwide increasingly sharpened emission regulations, the development of Gasoline Direct Injection and Diesel Direct Injection engines not only aims at the reduction of the emission of nitrogen oxides but also at the reduction of particulate emissions. Regarding present regulations, both tasks can be achieved solely with the help of exhaust after treatment systems. For the reduction of the emission of particulates, Gasoline (GPF) and diesel Particulate Filters (DPF) offer a solution and their implementation is intensely promoted. Under optimal conditions particulates retained on particulate filters are continuously oxidized with the exhaust residual oxygen so that the particulate filter (PF) is regenerated possibly without any additional intervention into the engine operating parameters. The regeneration behavior of PF depends on the reaction rates of soot particles with oxidative reactants at exhaust gas temperatures. The reaction rates of soot particles from internal combustion engines (ICE) often are discussed in terms of order/disorder on the particle nanoscale, the concentration and kind of functional groups on the particle surfaces, and the content of (mostly polycyclic aromatic) hydrocarbons in the soot. In this work the reactivity of different kinds of soot (soot from flames, soot from ICE, carbon black) under oxidation conditions representative for PF regeneration is investigated. Soot reactivity is determined in dynamic Temperature Programmed Oxidation (TPO) experiments and the soot primary particle morphology and nanostructure is investigated by High-Resolution Transmission Electron Microscopy (HRTEM). An image analysis method based on known methods from the literature and improving some infirmities is used to evaluate morphology and nanostructural characteristics. From this, primary particle size distributions, length and separation distance distributions as well as tortuosities of fringes within the primary particle structures are obtained. Further, UV-visible spectroscopy and Raman scattering and other diagnostic techniques are used to study the properties connected to the reactivity of soot and to corroborate the experimental findings. It is found that nanostructural characteristics predominantly affect reactivity. Oxidation rates are derived from TPO and interpreted on a molecular basis from quantum chemistry calculations revealing a replication/activation oxidation mechanism.

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“…In addition to the soot physicochemical properties, the potential correlations between the physical and chemical property parameters have also received attention [11][12][13][14][15][16]. Alfè et al [13] concluded that there is a structure-property relationship between the soot nanostructure and bulk properties, such as the amount of C-H groups.…”

Section: Introductionmentioning

confidence: 99%

Surface Functional Groups and Graphitization Degree of Soot in the Sooting History of Methane Premixed Flame

Liu

Fan

et al. 2017

SAE Technical Paper Series

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The evolution of surface functional groups (SFGs) and the graphitization degree of soot generated in premixed methane flames are studied and the correlation between them is discussed. Test soot samples were obtained from an optimized thermophoretic sampling system and probe sampling system. The SFGs of soot were determined by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) after removing the soluble impurities from the soot samples, while the graphitization degree of soot was characterized by Raman spectrum and electron energy loss spectroscopy (EELS). The results reveal that the number of aliphatic C-H groups and C=O groups shows an initial increase and then decrease in the sooting history. The large amount of aliphatic C-H groups and small amount of aromatic C-H groups in the early stage of the soot mass growth process indicate that aliphatic C-H groups make a major contribution to the early stage of soot mass growth. The higher graphitization degree of soot appears at low height above the burner when the graphite core is formed. The graphitization degree of soot rapidly decreases in the early mass growth stage then increases in the maturation process. The results from transmission electron microscopy (TEM), SFGs, and the graphitization degree verify the assumption that the nascent soot consists of a graphite-like core and an aliphatic shell. There is a strong correlation between SFGs and graphitization degree in the early stage of the soot mass growth process. During the soot maturation process, the correlation between SFGs and graphitization degree weakens. The SFGs may be related to the aggregate soot particle properties, such as fractal dimension.

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Utilization of HVO Fuel Properties in a High Efficiency Combustion System: Part 2: Relationship of Soot Characteristics with its Oxidation Behavior in DPF

Cited by 37 publications

References 27 publications

Effect of Renewable Fuels and Intake O2 Concentration on Diesel Engine Emission Characteristics and Reactive Oxygen Species (ROS) Formation

Effect of Renewable Fuels and Intake O2 Concentration on Diesel Engine Emission Characteristics and Reactive Oxygen Species (ROS) Formation

Why Soot is not Alike Soot: A Molecular/Nanostructural Approach to Low Temperature Soot Oxidation

Surface Functional Groups and Graphitization Degree of Soot in the Sooting History of Methane Premixed Flame

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