Impact of exhaust gas recirculation (EGR) on the oxidative reactivity of diesel engine soot

This paper expands the consideration of the factors affecting the nanostructure and oxidative reactivity of diesel soot to include the impact of exhaust gas recirculation (EGR). Past work showed that soot derived from oxygenated fuels such as biodiesel carries some surface oxygen functionality and thereby possesses higher reactivity than soot from conventional diesel fuel. In this work, results show that EGR exerts a strong influence on the physical properties of the soot which leads to enhanced oxidation rate. HRTEM images showed a dramatic difference between the burning modes of the soot generated under 0 and 20% EGR. The soot produced under 0% EGR strictly followed an external burning mode with no evidence of internal burning. In contrast, soot generated under 20% EGR exhibited dual burning modes: slow external burning and rapid internal burning. The results demonstrate clearly that highly reactive soot can be achieved by manipulating the physical properties of the soot via EGR.

[1]  R. V. Vander Wal,et al.  Analysis of HRTEM images for carbon nanostructure quantification , 2004 .

[2]  Robert Schlögl,et al.  Spectral properties of carbon black , 1999 .

[3]  Randy L. Vander Wal,et al.  Soot oxidation: dependence upon initial nanostructure , 2003 .

[4]  P. Salatino,et al.  The influence of thermal annealing on oxygen uptake and combustion rates of a bituminous coal char , 2007 .

[5]  R. L. Wal,et al.  Soot nanostructure: dependence upon synthesis conditions , 2004 .

[6]  W. Huffman.  The importance of active surface area in the heterogeneous reactions of carbon , 1991 .

[7]  P. Walker.  Complications introduced from gasification-induced densification of disordered carbons , 1996 .

[8]  David B. Williams,et al.  Quantitative near‐edge structure analysis of diamond‐like carbon in the electron microscope using a two‐window method , 1995 .

[9]  C. Roy,et al.  Solid state 13C-NMR spectroscopy and XRD studies of commercial and pyrolytic carbon blacks , 2000 .

[10]  A. Sarofim,et al.  Soot morphology: An application of image analysis in high‐resolution transmission electron microscopy , 1996, Microscopy research and technique.

[11]  Reinhard Niessner,et al.  Raman microspectroscopy of soot and related carbonaceous materials: Spectral analysis and structural information , 2005 .

[12]  P. Walker,et al.  Importance of carbon active sites in the gasification of coal chars , 1983 .

[13]  T. Kyotani,et al.  Effect of Microstructural Changes on Gasification Reactivity of Coal Chars during Low Temperature Gasification , 2002 .

[14]  Agus Setiabudi,et al.  The role of NO2 and O2 in the accelerated combustion of soot in diesel exhaust gases , 2004 .

[15]  R. V. Vander Wal,et al.  Carbon Nanostructure Examined by Lattice Fringe Analysis of High-Resolution Transmission Electron Microscopy Images , 2004, Applied spectroscopy.

[16]  G. Kaye.  Structural changes in heat treated carbon blacks , 1965 .

[17]  M. Hajaligol,et al.  HRTEM investigation of some commercially available furnace carbon blacks , 2004 .

[18]  Juhun Song,et al.  Examination of the oxidation behavior of biodiesel soot , 2006 .

[19]  B. Rand,et al.  Gas composition in laser pyrolysis of hydrocarbon-based mixtures: Influence on soot morphology , 2004 .

[20]  A. García,et al.  Structural Characterization of Graphite Materials Prepared from Anthracites of Different Characteristics: A Comparative Analysis , 2004 .

[21]  M.Rashid Khan.  Significance of char active surface area for appraising the reactivity of low- and high-temperature chars☆ , 1987 .

[22]  Ümit Özgür Köylü,et al.  Effect of operating conditions on the size, morphology, and concentration of submicrometer particulates emitted from a diesel engine , 2006 .

[23]  R. Essenhigh.  Influence of initial particle density on the reaction mode of porous carbon particles , 1994 .

[24]  I. C. Lewis,et al.  Thermal Reactivity of Polynuclear Aromatic Hydrocarbons1 , 1963 .

[25]  A. Bhowmick,et al.  Effect of carbon black on properties of rubber nanocomposites , 2005 .

[26]  R. Hurt,et al.  The phenomenon of gasification-induced carbon densification and its influence on pore structure evolution , 1988 .

[27]  C. C. Wright,et al.  X-Ray Diffraction Studies of a Graphitized Carbon - Changes in Interlayer Spacing and Binding Energy with Temperature. , 1953 .

[28]  Chris Jacobsen,et al.  Advantages of soft X-ray absorption over TEM-EELS for solid carbon studies––a comparative study on diesel soot with EELS and NEXAFS , 2005 .

[29]  J. V. Pustinger,et al.  X-RAY DIFFRACTION STUDIES ON CARBON GASIFICATION , 1954 .

[30]  Y. Sekine,et al.  Reactivity and structural change of coal char during steam gasification , 2005 .

[31]  Lenore C. Rainey,et al.  Application of High Resolution Electron Microscopy for the Characterization and Source Assignment of Diesel Particulates , 1996 .

[32]  T. W. Żerda,et al.  Raman studies of heat-treated carbon blacks , 1994 .

[33]  L. Radovic,et al.  Oxidation inhibition effects of phosphorus and boron in different carbon fabrics , 2003 .

[34]  D. Su,et al.  Morphology-controlled reactivity of carbonaceous materials towards oxidation , 2005 .

[35]  Raj Sekar,et al.  Morphological investigation of the microstructure, dimensions, and fractal geometry of diesel particulates , 2002 .

[36]  P. Harriott,et al.  Kinetics of oxidation and chemisorption of oxygen for porous carbons with high surface area , 1986 .

[37]  K. Nishikubo,et al.  Oxidative degradation of carbon blacks with nitric acid (I)—Changes in pore and crystallographic structures , 1998 .

[38]  R. Hurt,et al.  Equilibrium nanostructure of primary soot particles , 2000 .

[39]  N. Siddique,et al.  Raman spectroscopy of carbon-containing particles , 2001 .

[40]  S. D. Stasio,et al.  Comparative NEXAFS Study on Soot Obtained from an Ethylene/ Air Flame, a Diesel Engine, and Graphite , 2006 .

[41]  B. Stanmore,et al.  The oxidation of soot: a review of experiments, mechanisms and models , 2001 .

[42]  R. Niessner,et al.  Raman microspectroscopic analysis of changes in the chemical structure and reactivity of soot in a diesel exhaust aftertreatment model system. , 2007, Environmental science & technology.

[43]  T. Zerda,et al.  Raman studies of coals , 1981 .

[44]  M. Nakamizo,et al.  Raman spectra of the oxidized and polished surfaces of carbon , 1984 .

[45]  Hideyuki Takagi,et al.  XRD analysis of carbon stacking structure in coal during heat treatment , 2004 .

[46]  P. Ciambelli,et al.  Effect of Oxidation on the Microstructure of Carbon Blacks , 1996 .

[47]  Jean-Baptiste Donnet,et al.  A comparison of diesel engine soot with carbon black 1 1 Presented at the 1997 UK Carbon Group meeti , 1999 .

[48]  J. J. Pis,et al.  Relationship between structure and reactivity of carbonaceous materials , 2004 .

[49]  P. Buseck,et al.  Structural variations in individual carbonaceous particles from an urban aerosol , 1992 .

[50]  J. Lahaye,et al.  Fundamental issues in control of carbon gasification reactivity , 1991 .

[51]  Keiichi Yamamoto,et al.  Electron energy-loss spectroscopy of carbon onions , 1999 .

[52]  Arvind Suresh,et al.  Investigation of the oxidation behavior of diesel particulate matter , 2003 .

[53]  L. B. Ebert,et al.  Combustion ion tube soot from a diesel fuel/air mixture: issues in structure and reactivity , 1988 .

[54]  Yiannis A. Levendis,et al.  Soot surface area evolution during air oxidation as evaluated by small angle X-ray scattering and CO2 adsorption , 2005 .

[55]  David B. Williams,et al.  Transmission Electron Microscopy: A Textbook for Materials Science , 1996 .

[56]  C. Pickard,et al.  Electron energy-loss spectroscopy of electron states in isolated carbon nanostructures , 2001 .

[57]  E. A. Belenkov.  Formation of Graphite Structure in Carbon Crystallites , 2001 .

[58]  R. Dobbins,et al.  Crystallogenesis of Particles Formed in Hydrocarbon Combustion , 2000 .

[59]  Harry Marsh,et al.  Introduction to Carbon Science , 1989 .

[60]  B. Feng,et al.  Structural ordering of coal char during heat treatment and its impact on reactivity , 2002 .

[61]  R. L. Brown,et al.  Chemical theory of graphite-like molecules , 1985 .

[62]  F. A. Heckman,et al.  Progressive Oxidation of Selected Particles of Carbon Black: Further Evidence for a New Microstructural Model , 1966 .

[63]  P. Salatino,et al.  Evolution of Reactivity of Highly Porous Chars from Raman Microscopy , 2000 .

[64]  W. Smith,et al.  The Oxidation of Graphitized Carbon Black. , 1956 .

[65]  Yoshiyasu Fujitani,et al.  Microstructural changes of diesel soot during oxidation , 1991 .

[66]  S. Weiner,et al.  Structural characterization of modern and fossilized charcoal produced in natural fires as determined by using electron energy loss spectroscopy. , 2007, Chemistry.

[67]  Kouichi Miura,et al.  Factors affecting the reactivity of coal chars during gasification, and indices representing reactivity , 1989 .

[68]  Randy L. Vander Wal,et al.  HRTEM study of diesel soot collected from diesel particulate filters , 2007 .

[69]  C. Jacobsen,et al.  X-ray scattering and spectroscopy studies on diesel soot from oxygenated fuel under various engine load conditions , 2005 .

[70]  Christopher D. Simpson,et al.  Microstructure and oxidation behaviour of Euro IV diesel engine soot: a comparative study with synthetic model soot substances , 2004 .

[71]  I. Pasuk,et al.  Carbon nanopowders from the continuous-wave CO2 laser-induced pyrolysis of ethylene , 2003 .

[72]  J. Robertson,et al.  Raman spectroscopy of amorphous, nanostructured, diamond–like carbon, and nanodiamond , 2004, Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[73]  Covadonga Pevida,et al.  A comparison of different methods for predicting coal devolatilisation kinetics , 2001 .