The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

Mariano Sirignano - One of the best experts on this subject based on the ideXlab platform.

  • Experimental and numerical study on the effect of oxymethylene ether-3 (OME3) on soot particle formation
    Fuel, 2021
    Co-Authors: Federica Ferraro, Carmela Russo, Robert Schmitz, Christian Hasse, Mariano Sirignano
    Abstract:

    Abstract The reduction and control of Particulate matter generated by fossil fuel combustion are among the main issues for actual and future combustion devices due to the increasingly stringent emission regulations. Recently, various fuels have been investigated as a potential substitute or additive for diesel and gasoline. This work focuses on how oxymethylene ether-3 (OME3), the smallest promising OME compound, affects Carbon Particulate formation when blended with ethylene in burner-stabilized premixed flames at different equivalence ratios. Particle size distribution (PSD) and Laser-Induced Fluorescence (LIF) and Incandescence (LII) along with numerical (Conditional Quadrature Method of Moments – CQMOM, based on D’Anna physico-chemical soot model) investigations were conducted to study particle formation and growth in pure ethylene and ethylene/OME3 flames. The soot volume fraction and PSD indicate a reduction in the total number and the size of the soot particles at all equivalence ratios, while the number of small nanoparticles remains almost unchanged. The CQMOM model is able to predict similar trends for the soot volume fraction and, using the entropy maximization concept, the general shape of the PSD for both pure ethylene and OME3-blended flames, compared to the experimental measurements. Further, Carbon Particulate matter was thermophoretically sampled in the highest equivalence ratio conditions and spectroscopically analyzed. The soot structure was investigated using UV–Visible and Raman spectroscopy, finding a slightly higher aromaticity for the pure ethylene soot. FTIR analysis showed that Carbon Particulate matter produced from an OME3-doped flame contained larger amounts of oxygen, mainly in the form of C O.

  • The effect of butanol isomers on the formation of Carbon Particulate matter in fuel-rich premixed ethylene flames
    Combustion and Flame, 2019
    Co-Authors: Carmela Russo, Anna Ciajolo, Andrea D’anna, Mariano Sirignano
    Abstract:

    Abstract The effect of the butanol isomers on Carbon Particulate matter formation was studied by substituting up to 20% of the total Carbon of ethylene, fed to premixed flames with different equivalence ratios, with the four butanol isomers. Soot and condensed-phase nanostructures were tracked by means of particle size distribution (PSD) measurements and laser induced emission spectroscopy, namely fluorescence and incandescence. Butanol isomers, especially t-butanol, significantly reduced the total amount and the size of the soot particles, whereas a negligible effect was detected on condensed-phase nanostructures. PSDs were measured along with the aromaticity and functionalities of the Carbon Particulate matter thermophoretically sampled in the highest equivalence ratio condition. No significant differences were found among the different butanol isomers neither in the soot aggregate size, as measured by size exclusion chromatography, nor in the aromaticity, as evaluated by Raman and UV–vis spectroscopy, of the Particulate matter. Conversely, FTIR analysis showed that Carbon Particulate matter produced from 1-butanol and t-butanol-doped flames contained larger amounts of oxygen in form of C = O, C–O–C and OH functionalities. However, most of the differences in the oxygen functionalities disappeared after dichloromethane (DCM) treatment, suggesting that these oxygenated moieties belong to the condensed-phase nanostructures, soluble in DCM, rather than to soot particles.

  • Analysis of the chemical features of particles generated from ethylene and ethylene/2,5 dimethyl furan flames
    Combustion and Flame, 2016
    Co-Authors: Carmela Russo, Anna Ciajolo, Andrea D’anna, Mariano Sirignano
    Abstract:

    Abstract Carbon Particulate matter formed in fuel-rich atmospheric pressure premixed flames of ethylene and ethylene doped with 2,5 dimethyl furan (DMF) (20%) was analyzed in order to investigate the effect of fuel-borne oxygen on soot nanostructure and chemical functionalities. Particles were thermophoretically sampled on quartz plates and analyzed by techniques sensitive to the particle internal structure, namely FTIR, Raman and UV–vis spectroscopy. In nearly identical temperature, equivalence ratio and residence time conditions, the concentration of Particulate generated in the biofuel-doped flame was found to be far less of the concentration of ethylene flame Particulate. The similarity of UV–vis and Raman spectra showed that DMF addition to ethylene did not significantly change the aromatization process of Carbon Particulate in the flame. Complementary information on the functional groups located at the edge of the polyaromatic system was probed by FTIR analysis. FTIR spectra showed to be very similar regarding the Carbon network in particles produced in both flames. However, the infrared spectrum of the particles produced in the ethylene/DMF flame presented less intense peaks of aromatic hydrogen (900–700 cm −1 ) and a higher absorption in the 1300–1100 cm −1 wavenumber range. These changes in the infrared spectra were attributed to a higher amount of oxygen atoms that substitute hydrogen atoms at the edges of aromatic clusters of the ethylene/DMF soot particles. Oxygen content was estimated to be larger by few percentages in particles from ethylene/DMF with respect to particles from pure ethylene. This could be the cause for the enhanced reactivity of soot particles generally found for biofuel-derived soot.

  • Experimental and modeling study on the molecular weight distribution and properties of Carbon particles in premixed sooting flames
    Proceedings of the Combustion Institute, 2011
    Co-Authors: Mariano Sirignano, Anna Ciajolo, Michela Alfè, Antonio Tregrossi, Andrea D’anna
    Abstract:

    Abstract The evolution of the molecular weight (MW) distribution and structural properties of Carbon Particulate formed in methane, ethylene and benzene fuel-rich premixed flames, burning in similar conditions of maximum flame temperature, was experimentally measured and modeled. Both solubility and chromatographic separation of the Carbon Particulate allowed to follow the variation of molecular weight distributions of the different fractions. Structural properties of the Carbon Particulate in terms of H/C ratio and UV–visible absorption have been determined from particles inception to their maturation as a function of fuel identity. The experimental data were numerically predicted using a detailed gas-phase chemical kinetic mechanism coupled with a discrete sectional approach for the modeling of the molecule-to-particle process. The model was able to follow both particle concentration and structural properties for different fuels. In the benzene flame high molecular mass aromatic compounds appeared very early in the oxidation region and were no longer detected at the end of flame whereas aliphatic fuels showed both aromatic molecules and freshly-nucleated soot particles persisting downstream of the flame. Elemental analysis and UV–visible properties of the Carbon Particulate showed that also the graphitization process is earlier and much faster in the benzene flame whereas in aliphatic flames the final ordered structure is produced later on the flame and with a slower rate. Detailed modeling of the Carbon Particulate yields and properties confirms the differences in the evolution of Carbon Particulate and its structure in benzene and aliphatic flames, also individuating the classes of species: molecules and clusters of molecules, responsible for soot inception.

Anna Ciajolo - One of the best experts on this subject based on the ideXlab platform.

  • Thermophoretic sampling of large PAH (C ≥ 22–24) formed in flames
    Fuel, 2020
    Co-Authors: Carmela Russo, Barbara Apicella, Antonio Tregrossi, Maria Maddalena Oliano, Anna Ciajolo
    Abstract:

    Abstract The study of the transition from molecular to particle-like species involved in soot inception needs experimental strategies aiming to measure high molecular mass structures that could be important also for their effect on environment and human health. In this work, we have investigated the Carbon Particulate selectivity involved in the thermophoretic deposition used for the first time as a direct and fast sampling of high molecular weight aromatic species formed at the inception stage in an ethylene heavily sooting flame. Gravimetric analysis along with mass spectrometry, UV–Visible and fluorescence spectroscopy showed that the dichloromethane-extract of Carbon Particulate matter thermophoretically deposited on the substrate was much less than that sampled by a conventional water-cooled probe as it is composed only of high molecular weight condensed phases (C ≥ 22–24). Thermophoretic deposition is demonstrated to pre-separate, already at the sampling step, soot precursors of high molecular weight allowing their further analysis without the interference of the more abundant light polycyclic aromatic compounds (C

  • The effect of butanol isomers on the formation of Carbon Particulate matter in fuel-rich premixed ethylene flames
    Combustion and Flame, 2019
    Co-Authors: Carmela Russo, Anna Ciajolo, Andrea D’anna, Mariano Sirignano
    Abstract:

    Abstract The effect of the butanol isomers on Carbon Particulate matter formation was studied by substituting up to 20% of the total Carbon of ethylene, fed to premixed flames with different equivalence ratios, with the four butanol isomers. Soot and condensed-phase nanostructures were tracked by means of particle size distribution (PSD) measurements and laser induced emission spectroscopy, namely fluorescence and incandescence. Butanol isomers, especially t-butanol, significantly reduced the total amount and the size of the soot particles, whereas a negligible effect was detected on condensed-phase nanostructures. PSDs were measured along with the aromaticity and functionalities of the Carbon Particulate matter thermophoretically sampled in the highest equivalence ratio condition. No significant differences were found among the different butanol isomers neither in the soot aggregate size, as measured by size exclusion chromatography, nor in the aromaticity, as evaluated by Raman and UV–vis spectroscopy, of the Particulate matter. Conversely, FTIR analysis showed that Carbon Particulate matter produced from 1-butanol and t-butanol-doped flames contained larger amounts of oxygen in form of C = O, C–O–C and OH functionalities. However, most of the differences in the oxygen functionalities disappeared after dichloromethane (DCM) treatment, suggesting that these oxygenated moieties belong to the condensed-phase nanostructures, soluble in DCM, rather than to soot particles.

  • Effects of CO2 on submicronic Carbon Particulate (soot) formed during coal pyrolysis in a drop tube reactor
    Combustion and Flame, 2016
    Co-Authors: Osvalda Senneca, Barbara Apicella, S. Heuer, Martin Schiemann, Viktor Scherer, F. Stanzione, Anna Ciajolo, Carmela Russo
    Abstract:

    Abstract In oxycombustion and gasification processes coal pyrolysis occurs in CO 2 -rich atmospheres. The present work investigates the effect of such conditions on the quantity and quality of the submicronic Carbon Particulate produced. Pyrolysis experiments were carried out in either N 2 or CO 2 atmospheres in a laminar drop tube reactor, with wall temperatures of 1573 K, heating rates of 10 4 –10 5  K/s and residence times below 130 ms, so as to reproduce pyrolysis conditions comparable to those of pulverized coal-fired boilers. The Carbon Particulate sampled in the reactor was found to have bimodal distribution in the micronic and submicronic ranges. A method based on solvent extraction was applied to Carbon Particulate for separating the two modes and determining the relative mass contribution of micronic and submicronic fractions. In CO 2 atmosphere the amount of submicronic fraction of Carbon Particulate, referred to as soot, was found to be up to four times as much as upon N 2 experiments. Beside the larger formation of soot, relevant differences in terms of combustion reactivity, size distribution and chemical structure of the residual Carbon Particulate produced in CO 2 environment in respect to N 2 environment were observed by means of a large array of techniques including thermogravimetry, microscopy (SEM+EDX), FT-IR, UV–visible and Raman spectroscopy along with XRD and XPS techniques.

  • Analysis of the chemical features of particles generated from ethylene and ethylene/2,5 dimethyl furan flames
    Combustion and Flame, 2016
    Co-Authors: Carmela Russo, Anna Ciajolo, Andrea D’anna, Mariano Sirignano
    Abstract:

    Abstract Carbon Particulate matter formed in fuel-rich atmospheric pressure premixed flames of ethylene and ethylene doped with 2,5 dimethyl furan (DMF) (20%) was analyzed in order to investigate the effect of fuel-borne oxygen on soot nanostructure and chemical functionalities. Particles were thermophoretically sampled on quartz plates and analyzed by techniques sensitive to the particle internal structure, namely FTIR, Raman and UV–vis spectroscopy. In nearly identical temperature, equivalence ratio and residence time conditions, the concentration of Particulate generated in the biofuel-doped flame was found to be far less of the concentration of ethylene flame Particulate. The similarity of UV–vis and Raman spectra showed that DMF addition to ethylene did not significantly change the aromatization process of Carbon Particulate in the flame. Complementary information on the functional groups located at the edge of the polyaromatic system was probed by FTIR analysis. FTIR spectra showed to be very similar regarding the Carbon network in particles produced in both flames. However, the infrared spectrum of the particles produced in the ethylene/DMF flame presented less intense peaks of aromatic hydrogen (900–700 cm −1 ) and a higher absorption in the 1300–1100 cm −1 wavenumber range. These changes in the infrared spectra were attributed to a higher amount of oxygen atoms that substitute hydrogen atoms at the edges of aromatic clusters of the ethylene/DMF soot particles. Oxygen content was estimated to be larger by few percentages in particles from ethylene/DMF with respect to particles from pure ethylene. This could be the cause for the enhanced reactivity of soot particles generally found for biofuel-derived soot.

  • Soot particles at the aqueous interface and effects on foams stability
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2012
    Co-Authors: Eva Santini, Anna Ciajolo, Michela Alfè, Eduardo Guzmán, Francesca Ravera, Libero Liggieri, Michele Ferrari
    Abstract:

    Abstract This work is focused on the physico-chemical characterization of Carbonaceous nanometric Particulate produced from controlled combustion sources and on its effects on dynamic interfacial tension and surface dilational rheology of aqueous interfaces and on foamability. Since large quantities of surfactants are introduced into waste waters and water bodies by industrial activities, the properties of Carbon Particulate–laden liquid interfaces have been investigated in connection with the presence of surfactants. Aim of this work is to evidence the occurrence of synergetic effects between Carbonaceous Particulate and surfactants in affecting the above properties. Two Carbonaceous Particulates have been selected as representative of aromatic and aliphatic soot. These Particulates have been sampled from benzene and ethylene premixed laminar flames burning in fuel-rich conditions and characterized in terms of micro and nanostructures and size distribution. Water–air (W/A) interfacial properties of dispersions of the above Particulate have been investigated in presence of hexadecyltrimethylammonium bromide (CTAB), a widely used cationic surfactant. The dynamic surface tension and the surface dilational rheological behaviour have been studied in relationship with foam stability for environmental purpose and, as perspective, to explore new techniques involving the set up of stable dispersion of Carbon Particulate for the synthesis of microporous materials to be employed in CO2 capture. Comparison with the results previously obtained with commercially available Carbon black particles are also given.

Carmela Russo - One of the best experts on this subject based on the ideXlab platform.

  • Experimental and numerical study on the effect of oxymethylene ether-3 (OME3) on soot particle formation
    Fuel, 2021
    Co-Authors: Federica Ferraro, Carmela Russo, Robert Schmitz, Christian Hasse, Mariano Sirignano
    Abstract:

    Abstract The reduction and control of Particulate matter generated by fossil fuel combustion are among the main issues for actual and future combustion devices due to the increasingly stringent emission regulations. Recently, various fuels have been investigated as a potential substitute or additive for diesel and gasoline. This work focuses on how oxymethylene ether-3 (OME3), the smallest promising OME compound, affects Carbon Particulate formation when blended with ethylene in burner-stabilized premixed flames at different equivalence ratios. Particle size distribution (PSD) and Laser-Induced Fluorescence (LIF) and Incandescence (LII) along with numerical (Conditional Quadrature Method of Moments – CQMOM, based on D’Anna physico-chemical soot model) investigations were conducted to study particle formation and growth in pure ethylene and ethylene/OME3 flames. The soot volume fraction and PSD indicate a reduction in the total number and the size of the soot particles at all equivalence ratios, while the number of small nanoparticles remains almost unchanged. The CQMOM model is able to predict similar trends for the soot volume fraction and, using the entropy maximization concept, the general shape of the PSD for both pure ethylene and OME3-blended flames, compared to the experimental measurements. Further, Carbon Particulate matter was thermophoretically sampled in the highest equivalence ratio conditions and spectroscopically analyzed. The soot structure was investigated using UV–Visible and Raman spectroscopy, finding a slightly higher aromaticity for the pure ethylene soot. FTIR analysis showed that Carbon Particulate matter produced from an OME3-doped flame contained larger amounts of oxygen, mainly in the form of C O.

  • Thermophoretic sampling of large PAH (C ≥ 22–24) formed in flames
    Fuel, 2020
    Co-Authors: Carmela Russo, Barbara Apicella, Antonio Tregrossi, Maria Maddalena Oliano, Anna Ciajolo
    Abstract:

    Abstract The study of the transition from molecular to particle-like species involved in soot inception needs experimental strategies aiming to measure high molecular mass structures that could be important also for their effect on environment and human health. In this work, we have investigated the Carbon Particulate selectivity involved in the thermophoretic deposition used for the first time as a direct and fast sampling of high molecular weight aromatic species formed at the inception stage in an ethylene heavily sooting flame. Gravimetric analysis along with mass spectrometry, UV–Visible and fluorescence spectroscopy showed that the dichloromethane-extract of Carbon Particulate matter thermophoretically deposited on the substrate was much less than that sampled by a conventional water-cooled probe as it is composed only of high molecular weight condensed phases (C ≥ 22–24). Thermophoretic deposition is demonstrated to pre-separate, already at the sampling step, soot precursors of high molecular weight allowing their further analysis without the interference of the more abundant light polycyclic aromatic compounds (C

  • The effect of butanol isomers on the formation of Carbon Particulate matter in fuel-rich premixed ethylene flames
    Combustion and Flame, 2019
    Co-Authors: Carmela Russo, Anna Ciajolo, Andrea D’anna, Mariano Sirignano
    Abstract:

    Abstract The effect of the butanol isomers on Carbon Particulate matter formation was studied by substituting up to 20% of the total Carbon of ethylene, fed to premixed flames with different equivalence ratios, with the four butanol isomers. Soot and condensed-phase nanostructures were tracked by means of particle size distribution (PSD) measurements and laser induced emission spectroscopy, namely fluorescence and incandescence. Butanol isomers, especially t-butanol, significantly reduced the total amount and the size of the soot particles, whereas a negligible effect was detected on condensed-phase nanostructures. PSDs were measured along with the aromaticity and functionalities of the Carbon Particulate matter thermophoretically sampled in the highest equivalence ratio condition. No significant differences were found among the different butanol isomers neither in the soot aggregate size, as measured by size exclusion chromatography, nor in the aromaticity, as evaluated by Raman and UV–vis spectroscopy, of the Particulate matter. Conversely, FTIR analysis showed that Carbon Particulate matter produced from 1-butanol and t-butanol-doped flames contained larger amounts of oxygen in form of C = O, C–O–C and OH functionalities. However, most of the differences in the oxygen functionalities disappeared after dichloromethane (DCM) treatment, suggesting that these oxygenated moieties belong to the condensed-phase nanostructures, soluble in DCM, rather than to soot particles.

  • Effects of CO2 on submicronic Carbon Particulate (soot) formed during coal pyrolysis in a drop tube reactor
    Combustion and Flame, 2016
    Co-Authors: Osvalda Senneca, Barbara Apicella, S. Heuer, Martin Schiemann, Viktor Scherer, F. Stanzione, Anna Ciajolo, Carmela Russo
    Abstract:

    Abstract In oxycombustion and gasification processes coal pyrolysis occurs in CO 2 -rich atmospheres. The present work investigates the effect of such conditions on the quantity and quality of the submicronic Carbon Particulate produced. Pyrolysis experiments were carried out in either N 2 or CO 2 atmospheres in a laminar drop tube reactor, with wall temperatures of 1573 K, heating rates of 10 4 –10 5  K/s and residence times below 130 ms, so as to reproduce pyrolysis conditions comparable to those of pulverized coal-fired boilers. The Carbon Particulate sampled in the reactor was found to have bimodal distribution in the micronic and submicronic ranges. A method based on solvent extraction was applied to Carbon Particulate for separating the two modes and determining the relative mass contribution of micronic and submicronic fractions. In CO 2 atmosphere the amount of submicronic fraction of Carbon Particulate, referred to as soot, was found to be up to four times as much as upon N 2 experiments. Beside the larger formation of soot, relevant differences in terms of combustion reactivity, size distribution and chemical structure of the residual Carbon Particulate produced in CO 2 environment in respect to N 2 environment were observed by means of a large array of techniques including thermogravimetry, microscopy (SEM+EDX), FT-IR, UV–visible and Raman spectroscopy along with XRD and XPS techniques.

  • Analysis of the chemical features of particles generated from ethylene and ethylene/2,5 dimethyl furan flames
    Combustion and Flame, 2016
    Co-Authors: Carmela Russo, Anna Ciajolo, Andrea D’anna, Mariano Sirignano
    Abstract:

    Abstract Carbon Particulate matter formed in fuel-rich atmospheric pressure premixed flames of ethylene and ethylene doped with 2,5 dimethyl furan (DMF) (20%) was analyzed in order to investigate the effect of fuel-borne oxygen on soot nanostructure and chemical functionalities. Particles were thermophoretically sampled on quartz plates and analyzed by techniques sensitive to the particle internal structure, namely FTIR, Raman and UV–vis spectroscopy. In nearly identical temperature, equivalence ratio and residence time conditions, the concentration of Particulate generated in the biofuel-doped flame was found to be far less of the concentration of ethylene flame Particulate. The similarity of UV–vis and Raman spectra showed that DMF addition to ethylene did not significantly change the aromatization process of Carbon Particulate in the flame. Complementary information on the functional groups located at the edge of the polyaromatic system was probed by FTIR analysis. FTIR spectra showed to be very similar regarding the Carbon network in particles produced in both flames. However, the infrared spectrum of the particles produced in the ethylene/DMF flame presented less intense peaks of aromatic hydrogen (900–700 cm −1 ) and a higher absorption in the 1300–1100 cm −1 wavenumber range. These changes in the infrared spectra were attributed to a higher amount of oxygen atoms that substitute hydrogen atoms at the edges of aromatic clusters of the ethylene/DMF soot particles. Oxygen content was estimated to be larger by few percentages in particles from ethylene/DMF with respect to particles from pure ethylene. This could be the cause for the enhanced reactivity of soot particles generally found for biofuel-derived soot.

Andrea D’anna - One of the best experts on this subject based on the ideXlab platform.

  • The effect of butanol isomers on the formation of Carbon Particulate matter in fuel-rich premixed ethylene flames
    Combustion and Flame, 2019
    Co-Authors: Carmela Russo, Anna Ciajolo, Andrea D’anna, Mariano Sirignano
    Abstract:

    Abstract The effect of the butanol isomers on Carbon Particulate matter formation was studied by substituting up to 20% of the total Carbon of ethylene, fed to premixed flames with different equivalence ratios, with the four butanol isomers. Soot and condensed-phase nanostructures were tracked by means of particle size distribution (PSD) measurements and laser induced emission spectroscopy, namely fluorescence and incandescence. Butanol isomers, especially t-butanol, significantly reduced the total amount and the size of the soot particles, whereas a negligible effect was detected on condensed-phase nanostructures. PSDs were measured along with the aromaticity and functionalities of the Carbon Particulate matter thermophoretically sampled in the highest equivalence ratio condition. No significant differences were found among the different butanol isomers neither in the soot aggregate size, as measured by size exclusion chromatography, nor in the aromaticity, as evaluated by Raman and UV–vis spectroscopy, of the Particulate matter. Conversely, FTIR analysis showed that Carbon Particulate matter produced from 1-butanol and t-butanol-doped flames contained larger amounts of oxygen in form of C = O, C–O–C and OH functionalities. However, most of the differences in the oxygen functionalities disappeared after dichloromethane (DCM) treatment, suggesting that these oxygenated moieties belong to the condensed-phase nanostructures, soluble in DCM, rather than to soot particles.

  • Analysis of the chemical features of particles generated from ethylene and ethylene/2,5 dimethyl furan flames
    Combustion and Flame, 2016
    Co-Authors: Carmela Russo, Anna Ciajolo, Andrea D’anna, Mariano Sirignano
    Abstract:

    Abstract Carbon Particulate matter formed in fuel-rich atmospheric pressure premixed flames of ethylene and ethylene doped with 2,5 dimethyl furan (DMF) (20%) was analyzed in order to investigate the effect of fuel-borne oxygen on soot nanostructure and chemical functionalities. Particles were thermophoretically sampled on quartz plates and analyzed by techniques sensitive to the particle internal structure, namely FTIR, Raman and UV–vis spectroscopy. In nearly identical temperature, equivalence ratio and residence time conditions, the concentration of Particulate generated in the biofuel-doped flame was found to be far less of the concentration of ethylene flame Particulate. The similarity of UV–vis and Raman spectra showed that DMF addition to ethylene did not significantly change the aromatization process of Carbon Particulate in the flame. Complementary information on the functional groups located at the edge of the polyaromatic system was probed by FTIR analysis. FTIR spectra showed to be very similar regarding the Carbon network in particles produced in both flames. However, the infrared spectrum of the particles produced in the ethylene/DMF flame presented less intense peaks of aromatic hydrogen (900–700 cm −1 ) and a higher absorption in the 1300–1100 cm −1 wavenumber range. These changes in the infrared spectra were attributed to a higher amount of oxygen atoms that substitute hydrogen atoms at the edges of aromatic clusters of the ethylene/DMF soot particles. Oxygen content was estimated to be larger by few percentages in particles from ethylene/DMF with respect to particles from pure ethylene. This could be the cause for the enhanced reactivity of soot particles generally found for biofuel-derived soot.

  • Experimental and modeling study on the molecular weight distribution and properties of Carbon particles in premixed sooting flames
    Proceedings of the Combustion Institute, 2011
    Co-Authors: Mariano Sirignano, Anna Ciajolo, Michela Alfè, Antonio Tregrossi, Andrea D’anna
    Abstract:

    Abstract The evolution of the molecular weight (MW) distribution and structural properties of Carbon Particulate formed in methane, ethylene and benzene fuel-rich premixed flames, burning in similar conditions of maximum flame temperature, was experimentally measured and modeled. Both solubility and chromatographic separation of the Carbon Particulate allowed to follow the variation of molecular weight distributions of the different fractions. Structural properties of the Carbon Particulate in terms of H/C ratio and UV–visible absorption have been determined from particles inception to their maturation as a function of fuel identity. The experimental data were numerically predicted using a detailed gas-phase chemical kinetic mechanism coupled with a discrete sectional approach for the modeling of the molecule-to-particle process. The model was able to follow both particle concentration and structural properties for different fuels. In the benzene flame high molecular mass aromatic compounds appeared very early in the oxidation region and were no longer detected at the end of flame whereas aliphatic fuels showed both aromatic molecules and freshly-nucleated soot particles persisting downstream of the flame. Elemental analysis and UV–visible properties of the Carbon Particulate showed that also the graphitization process is earlier and much faster in the benzene flame whereas in aliphatic flames the final ordered structure is produced later on the flame and with a slower rate. Detailed modeling of the Carbon Particulate yields and properties confirms the differences in the evolution of Carbon Particulate and its structure in benzene and aliphatic flames, also individuating the classes of species: molecules and clusters of molecules, responsible for soot inception.

G.a Stratakis - One of the best experts on this subject based on the ideXlab platform.

  • Thermogravimetric analysis of soot emitted by a modern diesel engine run on catalyst-doped fuel
    Combustion and Flame, 2003
    Co-Authors: G.a Stratakis, Anastasios M. Stamatelos
    Abstract:

    Understanding the mechanisms that affect catalytic activity in porous ceramic diesel Particulate filters (DPF) at the temperature range 200 to 400°C is important for the successful modeling of the initiation and evolution of catalytic regeneration by use of fuel additives. This refers not only to the dry Carbon Particulate, but also to the volatile hydroCarbons adsorbed on it. In this paper, a detailed analysis of the hydroCarbon adsorption-desorption and oxidation behavior of diesel Particulate emitted by a modern diesel engine and collected on a SiC diesel filter is performed by use of thermogravimetric and differential scanning calorimetry analysis (TGA-DSC). Non-isothermal tests were performed with samples collected directly from a ceramic filter connected to the exhaust system of the diesel engine running under low and medium speed and load operating conditions with and without fuel additive. Fuel additive concentration was varied to investigate its effect on the soot oxidation behavior. Based on the TGA data, the kinetic parameters of the soot oxidation reaction were calculated. The effect of volatile adsorbed hydroCarbons on the soot oxidation reaction was evaluated by comparing the calculated activation energies for samples collected from the center and the periphery of the filter at various exhaust temperatures prevailing at filter loading phase. In particular it was seen that the catalytic activity of the fuel additive is enhanced by the presence of the volatile organic components.

  • Thermogravimetric analysis of soot emitted by a modern diesel engine run on catalyst-doped fuel
    Combustion and Flame, 2003
    Co-Authors: G.a Stratakis
    Abstract:

    Understanding the mechanisms that affect catalytic activity in porous ceramic diesel Particulate filters (DPF) at the temperature range 200 to 400degreesC is important for the successful modeling of the initiation and evolution of catalytic regeneration by use of fuel additives. This refers not only to the dry Carbon Particulate, but also to the volatile hydroCarbons adsorbed on it. In this paper, a detailed analysis of the hydroCarbon adsorption-desorption and oxidation behavior of diesel Particulate emitted by a modern diesel engine and collected on a SiC diesel filter is performed by use of thermogravimetric and differential scanning calorimetry analysis (TGA-DSC). Non-isothermal tests were performed with samples collected directly from a ceramic filter connected to the exhaust system of the diesel engine running under low and medium speed and load operating conditions with and without fuel additive. Fuel additive concentration was varied to investigate its effect on the soot oxidation behavior. Based on the TGA data, the kinetic parameters of the soot oxidation reaction were calculated. The effect of volatile adsorbed hydroCarbons on the soot oxidation reaction was evaluated by comparing the calculated activation energies for samples collected from the center and the periphery of the filter at various exhaust temperatures prevailing at filter loading phase. In particular it was seen that the catalytic activity of the fuel additive is enhanced by the presence of the volatile organic components. (C) 2003 The Combustion Institute. All rights reserved