Detailed analysis of kinetic reactions in soot oxidation by simulated diesel exhaust emissions

Lee, Kyeong O.; Seong, Heeje; Choi, Seung M.

doi:10.1016/j.proci.2012.06.121

Cited by 27 publications

(18 citation statements)

References 16 publications

(29 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is in agreement with other authors, such as Stanmore et al [2], who found similar activation energy for this reaction (50 kJ/mol), Kandylas et al [50], who reported 40 kJ/mol, and also Lee et al, reporting 44 kJ/mol [40]. This fact is in accordance with the idea that NO 2 is much more active than O 2 and can directly attack the carbon surface [28].…”

Section: Ln(r) = Ln(a) + Ln(f(c P)) + E a /R·1/t (3)supporting

confidence: 92%

“…Numerous researchers have conducted experiments to define the kinetics associated to soot combustion, but the activation energy values reported present discrepancies, because they can be quite dependent on the experimental conditions, mainly the gaseous atmosphere used, due to the synergic effects among the gaseous reactants and the type of contact among the soot and the catalyst particles [28,40].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Opportunities for ceria-based mixed oxides versus commercial platinum-based catalysts in the soot combustion reaction. Mechanistic implications

Giménez-Mañogil¹,

Garcı́a-Garcı́a²

2015

Fuel Processing Technology

View full text Add to dashboard Cite

The aim of this paper is to study the activities of ceria-zirconia and copper/ceriazirconia catalysts, comparing with a commercial platinum/alumina catalyst, for soot combustion reaction under different gas atmospheres and loose contact mode (simulating diesel exhaust conditions), in order to analyse the kinetics and to deduce mechanistic implications.Activity tests were performed under isothermal and TPR conditions. The NO oxidation to NO 2 was studied as well. It was checked that mass transfer limitations were not influencing the rate measurements. Global activation energies for the catalysed and non-catalysed soot combustion were calculated and properly discussed.The results reveal that ceria-based catalysts greatly enhance their activities under NOx/O 2 between 425ºC and 450ºC, due to the "active oxygen"-assisted soot combustion. Remarkably, copper/ceria-zirconia shows a slightly higher soot combustion rate than the Pt-based catalyst (under NOx/O 2 , at 450ºC).

show abstract

Section: Ln(r) = Ln(a) + Ln(f(c P)) + E a /R·1/t (3)supporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Opportunities for ceria-based mixed oxides versus commercial platinum-based catalysts in the soot combustion reaction. Mechanistic implications

Giménez-Mañogil¹,

Garcı́a-Garcı́a²

2015

Fuel Processing Technology

View full text Add to dashboard Cite

show abstract

“…Arrhenius-type equation in Eq. (1) is well accepted for the temperature dependence of soot oxidation by oxygen [23,24], ‫ݎ‬ ൌ ௗఈ ௗ௧ ൌ ‫ܣ‬ ൈ ݁ ିா ೌ /ோ் ൈ ሺ1 െ ߙሻ…”

Section: Previous Studies Of the Reaction Kinetics Of Carbonaceous Somentioning

confidence: 99%

Oxidation characteristics of gasoline direct-injection (GDI) engine soot: Catalytic effects of ash and modified kinetic correlation

Choi

Seong

2015

Combustion and Flame

Self Cite

View full text Add to dashboard Cite

In this paper, experimental analyses are conducted into the GDI soot oxidation characteristics as dependent on engine operating conditions. Soot is sampled at various engine operating conditions of a commercial 2.4 L GDI engine with a naturally aspirated, homogeneous, and stoichiometric operation strategy. The oxidation reactivity, ash composition, and carbon nanostructure of the GDI soot samples are analyzed using thermogravimetric analysis (TGA), scanning electron microscope-energy-dispersive spectroscopy (SEM-EDS), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy. Based on the analyses, a global GDI soot oxidation mechanism is proposed which includes the effects of soluble organic fractions (SOF)/weakly bonded carbon (WBC), and three types of ash on GDI soot oxidation. The results show that GDI soot contains an order of magnitude higher ash fraction than does conventional diesel soot, and oxidation reactivity is significantly enhanced by the catalytic effects of ash, as a function of ash content in soot. A modified empirical kinetic correlation for GDI soot oxidation is suggested on the basis of the results, and the modified kinetic correlation predicts the GDI soot oxidation rate accurately for various engine operation points at wide ranges of soot conversion and temperature without modifying kinetic parameters. The kinetic parameters are determined from isothermal and non-isothermal thremogravimetric analysis (TGA) soot oxidation tests; the methods are elucidated in detail.

show abstract

“…Because NO 2 effect was observed to be insignificant at these high temperatures [22], TEM observations were not performed for partially oxidized soot with NO 2 added. Noticeable shell-like structures were also demonstrated at the increased temperatures of 600 and 700°C.…”

Section: Tem Observations Of Partially Oxidized Sootmentioning

confidence: 99%

Oxidation-derived maturing process of soot, dependent on O2–NO2 mixtures and temperatures

Seong

Choi

2015

Carbon

Self Cite

View full text Add to dashboard Cite

a b s t r a c tOxidizer-and temperature-dependent soot properties were investigated to better understand soot oxidation process. For this work, partially oxidized Printex-U samples as surrogate soot, under three different O 2 -NO 2 mixtures, were analyzed by using the high resolution-transmission electron microscope, Raman microscope and Fourier transform infrared spectroscopy-attenuated total reflectance. The results show that the maturing process was much dependent on NO 2 content in the O 2 -NO 2 mixture: with no NO 2 added, soot oxidized through the internal-burning out process, whereas with increased NO 2 in the mixture, soot tended to oxidize through the external burning process. As the NO 2 content increased, the preferential oxidation of less-ordered carbon crystallites decreased and as a result the maturing process was delayed. Internal burning-out process by O 2 only was also verified at various temperatures and with actual engine soot such as diesel soot and gasoline direct-injection (GDI) soot by TEM observations. Despite similar internal burning-out process, however, it was shown that oxidation at increased temperature resulted in relatively less-ordered soot, implying that soot maturing process was delayed with temperature. Since soot oxidation rate increased with temperature, the increase in oxidation temperature seems to diminish preference on short-ranged crystallites like more efficient O 2 -NO 2 cases.

show abstract

Detailed analysis of kinetic reactions in soot oxidation by simulated diesel exhaust emissions

Cited by 27 publications

References 16 publications

Opportunities for ceria-based mixed oxides versus commercial platinum-based catalysts in the soot combustion reaction. Mechanistic implications

Opportunities for ceria-based mixed oxides versus commercial platinum-based catalysts in the soot combustion reaction. Mechanistic implications

Oxidation characteristics of gasoline direct-injection (GDI) engine soot: Catalytic effects of ash and modified kinetic correlation

Oxidation-derived maturing process of soot, dependent on O2–NO2 mixtures and temperatures

Contact Info

Product

Resources

About