The Experts below are selected from a list of 153 Experts worldwide ranked by ideXlab platform

Sirirat Jitkarnka - One of the best experts on this subject based on the ideXlab platform.

  • Roles of ruthenium on catalytic pyrolysis of waste tire and the changes of its activity upon the rate of calcination
    Journal of Analytical and Applied Pyrolysis, 2010
    Co-Authors: Nguyễn Anh Dũng, Walairat Tanglumlert, Sujitra Wongkasemjit, Sirirat Jitkarnka
    Abstract:

    Abstract The catalytic pyrolysis of waste tire with Ru/SBA-1 catalysts was studied. The roles of ruthenium were elucidated since the support, a pure silica SBA-1 synthesized via silatrane route, was proven to be catalytically inactive and its structure retained after pyrolysis. Ruthenium clusters increased the yield of gaseous products, approximately 2 times as compared to thermal pyrolysis, at the expense of the liquid yield. They also decreased poly- and Polar-Aromatics and consequently produced lighter oil. The heating rates (1 °C/min, 5 °C/min, and 10 °C/min) during calcination were found to strongly influence the activity of the Ru/SBA-1 catalysts. The catalyst calcined with a heating rate of 5 °C/min exhibited the highest activity on poly- and Polar-Aromatics reduction and light oil production. The highest activity of this catalyst was attributed to its smallest mean ruthenium particle size and its highest sulfur tolerance.

  • Effects of pyrolysis temperature and Pt-loaded catalysts on Polar-aromatic content in tire-derived oil
    Applied Catalysis B-environmental, 2009
    Co-Authors: Nguyễn Anh Dũng, Sujitra Wongkasemjit, Sirirat Jitkarnka
    Abstract:

    This study investigates the influences of pyrolysis temperatures and Pt-supported catalysts on Polar-aromatic content in the oils obtained from pyrolysis of waste tire. These Polar-aromatic compounds are mostly the sulfur-containing Aromatics since oxygen is prohibited in pyrolysis. The experimental results indicated that pyrolysis temperatures strongly affected the Polar-aromatic content in the derived oils. Namely, the increase in pyrolysis temperature in the tested range produced not only a higher amount of Polar-Aromatics but also heavier Polar-aromatic compounds. All studied catalysts decreased the Polar-aromatic content in the oils drastically. In addition, it was found that the introduction of the studied catalyst also led to the production of lighter Polar-aromatic compounds with respect to that produced from thermal pyrolysis. Comparing the two acid catalysts, HBETA exhibited higher activity for Polar-aromatic reduction as compared to HMOR, which was ascribed to its higher medium and strong acid site density, smaller particle size and 3D-structure. The Pt supported on HMOR and HBETA catalysts showed better Polar-aromatic reduction activity than their corresponding acid catalysts. And, a slightly higher catalytic activity was observed over Pt/HBETA than Pt/HMOR, which was mainly due to the higher Pt dispersion of Pt/HBETA catalyst.

J-f Masson - One of the best experts on this subject based on the ideXlab platform.

  • low temperature bitumen stiffness and viscous paraffinic nano and micro domains by cryogenic afm and pdm
    Journal of Microscopy, 2007
    Co-Authors: J-f Masson, V Leblond, J Margeson, S Bundaloperc
    Abstract:

    Summary In an effort to better understand the structure and behaviour of bitumen in low temperature, we describe the first use of cryogenic atomic force microscopy and phase detection microscopy to characterize bitumen nano- and micro-structures. The results were interpreted in light of glass transition temperatures (Tgs) for bitumen fractions. The domains visible by microscopy, the catana, peri and para phases, were attributed to domains rich in asphaltenes, naphthene and Polar Aromatics, and saturates, respectively. Between −10°C and −30°C, atomic force microscopy images revealed topographic features not visible in atomic force microscopy images acquired at room temperature. According to phase detection microscopy and Tgs, the features were assigned to viscous unfrozen saturates. Upon cooling to −72°C, unfrozen domains of 20–400 nm were observed. These domains were found in the paraphase rich in saturates and in the periphase rich in naphthene Aromatics and Polar Aromatics. The findings indicate that new viscous domains form upon cooling to low temperatures owing to phase segregation, and that some bitumens are never entirely rigid in low temperatures.

  • Low-temperature bitumen stiffness and viscous paraffinic nano- and micro-domains by cryogenic AFM and PDM
    Journal of Microscopy, 2007
    Co-Authors: J-f Masson, V Leblond, J Margeson, Slaðana Bundalo-perc
    Abstract:

    In an effort to better understand the structure and behaviour of bitumen in low temperature, we describe the first use of cryogenic atomic force microscopy and phase detection microscopy to characterize bitumen nano- and micro-structures. The results were interpreted in light of glass transition temperatures (T(g)s) for bitumen fractions. The domains visible by microscopy, the catana, peri and para phases, were attributed to domains rich in asphaltenes, naphthene and Polar Aromatics, and saturates, respectively. Between -10 degrees C and -30 degrees C, atomic force microscopy images revealed topographic features not visible in atomic force microscopy images acquired at room temperature. According to phase detection microscopy and T(g)s, the features were assigned to viscous unfrozen saturates. Upon cooling to -72 degrees C, unfrozen domains of 20-400 nm were observed. These domains were found in the paraphase rich in saturates and in the periphase rich in naphthene Aromatics and Polar Aromatics. The findings indicate that new viscous domains form upon cooling to low temperatures owing to phase segregation, and that some bitumens are never entirely rigid in low temperatures.

  • Bitumen morphologies by phase-detection atomic force microscopy.
    Journal of microscopy, 2006
    Co-Authors: J-f Masson, V Leblond, J Margeson
    Abstract:

    Summary Bitumen is a complex mixture of hydrocarbons for which microstructural knowledge is incomplete. In an effort to detail this microstructure, 13 bitumens were analysed by phase-detection atomic force microscopy. Based on morphology, the bitumens could be classified into three distinct groups. One group showed fine domains down to 0.1 microm, another showed domains of about 1 microm, and a third group showed up to four different domains or phases of different sizes and shapes. No correlation was found between the atomic force microscopy morphology and the composition based on asphaltenes, Polar Aromatics, naphthene Aromatics and saturates. A high correlation was found between the area of the 'bee-like' structures and the vanadium and nickel content in bitumen, and between the atomic force microscopy groups and the average size of molecular planes made of fused Aromatics. The morphology and the molecular arrangements in bitumen thus appear to be partly governed by the molecular planes and the Polarity defined by metallic cations.

Nguyễn Anh Dũng - One of the best experts on this subject based on the ideXlab platform.

  • Roles of ruthenium on catalytic pyrolysis of waste tire and the changes of its activity upon the rate of calcination
    Journal of Analytical and Applied Pyrolysis, 2010
    Co-Authors: Nguyễn Anh Dũng, Walairat Tanglumlert, Sujitra Wongkasemjit, Sirirat Jitkarnka
    Abstract:

    Abstract The catalytic pyrolysis of waste tire with Ru/SBA-1 catalysts was studied. The roles of ruthenium were elucidated since the support, a pure silica SBA-1 synthesized via silatrane route, was proven to be catalytically inactive and its structure retained after pyrolysis. Ruthenium clusters increased the yield of gaseous products, approximately 2 times as compared to thermal pyrolysis, at the expense of the liquid yield. They also decreased poly- and Polar-Aromatics and consequently produced lighter oil. The heating rates (1 °C/min, 5 °C/min, and 10 °C/min) during calcination were found to strongly influence the activity of the Ru/SBA-1 catalysts. The catalyst calcined with a heating rate of 5 °C/min exhibited the highest activity on poly- and Polar-Aromatics reduction and light oil production. The highest activity of this catalyst was attributed to its smallest mean ruthenium particle size and its highest sulfur tolerance.

  • Effects of pyrolysis temperature and Pt-loaded catalysts on Polar-aromatic content in tire-derived oil
    Applied Catalysis B-environmental, 2009
    Co-Authors: Nguyễn Anh Dũng, Sujitra Wongkasemjit, Sirirat Jitkarnka
    Abstract:

    This study investigates the influences of pyrolysis temperatures and Pt-supported catalysts on Polar-aromatic content in the oils obtained from pyrolysis of waste tire. These Polar-aromatic compounds are mostly the sulfur-containing Aromatics since oxygen is prohibited in pyrolysis. The experimental results indicated that pyrolysis temperatures strongly affected the Polar-aromatic content in the derived oils. Namely, the increase in pyrolysis temperature in the tested range produced not only a higher amount of Polar-Aromatics but also heavier Polar-aromatic compounds. All studied catalysts decreased the Polar-aromatic content in the oils drastically. In addition, it was found that the introduction of the studied catalyst also led to the production of lighter Polar-aromatic compounds with respect to that produced from thermal pyrolysis. Comparing the two acid catalysts, HBETA exhibited higher activity for Polar-aromatic reduction as compared to HMOR, which was ascribed to its higher medium and strong acid site density, smaller particle size and 3D-structure. The Pt supported on HMOR and HBETA catalysts showed better Polar-aromatic reduction activity than their corresponding acid catalysts. And, a slightly higher catalytic activity was observed over Pt/HBETA than Pt/HMOR, which was mainly due to the higher Pt dispersion of Pt/HBETA catalyst.

Wei Wang - One of the best experts on this subject based on the ideXlab platform.

  • Study on Thermal Oxidation of Asphalt Fractions by In-situ FTIR Analysis
    2016
    Co-Authors: Xue Juan Cao, Yun Bo Lei, Wei Wang
    Abstract:

    which are saturates, naphetene Aromatics, Polar-Aromatics and asphaltenes. The thermal oxidation process of each fraction was studied by in-situ Fourier transform infrared (FTIR) analysis in different atmospheres in this paper. And the results show that each fraction in nitrogen atmosphere has no obvious aging phenomenon, while in oxygen and air atmosphere, only saturates and naphetene Aromatics have a drastic change because of thermal oxidation, and Polar-Aromatics and asphaltenes almost keep unchanged. When adding 2.5% antioxidant 300 or 5 % SBS respectively to saturates and naphthene Aromatics, it can be found from the results that the degree of thermal oxidation of these two components decrease

  • Study on Thermal Oxidation of Asphalt Fractions by In Situ FTIR Analysis
    Advanced Materials Research, 2010
    Co-Authors: Xue Juan Cao, Yun Bo Lei, Wei Wang
    Abstract:

    Base asphalt can be separated into four fractions, which are saturates, naphetene Aromatics, Polar-Aromatics and asphaltenes. The thermal oxidation process of each fraction was studied by in-situ Fourier transform infrared (FTIR) analysis in different atmospheres in this paper. And the results show that each fraction in nitrogen atmosphere has no obvious aging phenomenon, while in oxygen and air atmosphere, only saturates and naphetene Aromatics have a drastic change because of thermal oxidation, and Polar-Aromatics and asphaltenes almost keep unchanged. When adding 2.5% antioxidant 300 or 5% SBS respectively to saturates and naphthene Aromatics, it can be found from the results that the degree of thermal oxidation of these two components decrease.

  • AN in situ13C MAS NMR study of the zeolite-catalyzed alkylation of Polar Aromatics
    Studies in Surface Science and Catalysis, 2004
    Co-Authors: Irina I. Ivanova, Wei Wang, E. B. Pomakhina, I. B. Borodina, A. I. Rebrov, Jens Weitkamp, Michael Hunger
    Abstract:

    Abstract In situ 13 C MAS NMR was applied to study the mechanisms of the N-alkylation of aniline and of the O-alkylation of phenol with methanol on acidic (H-Y) and basic (CsOH/CsNa-Y) zeolite Y catalysts. Methanol- 13 C was the labeled reactant. The results point to similar mechanisms of the N- and O-alkylation on Bronsted acid sites including a dehydration of methanol towards dimethyl ether (DME) or surface methoxy groups, which further react with aniline to N-methyalnilinium, N,N-dimethylanilinium, and N,N, N-trimethylanilinium cations or a direct reaction of phenol and methanol towards anisole. At variance, different mechanistic pathways were observed on basic zeolite Y: N-alkylation is shown to proceed via methanol dehydrogenation leading to the formation of formaldehyde species responsible for further methylation, while O-alkylation includes the formation of phenolate ions initiating the alkylation reaction.

J Margeson - One of the best experts on this subject based on the ideXlab platform.

  • low temperature bitumen stiffness and viscous paraffinic nano and micro domains by cryogenic afm and pdm
    Journal of Microscopy, 2007
    Co-Authors: J-f Masson, V Leblond, J Margeson, S Bundaloperc
    Abstract:

    Summary In an effort to better understand the structure and behaviour of bitumen in low temperature, we describe the first use of cryogenic atomic force microscopy and phase detection microscopy to characterize bitumen nano- and micro-structures. The results were interpreted in light of glass transition temperatures (Tgs) for bitumen fractions. The domains visible by microscopy, the catana, peri and para phases, were attributed to domains rich in asphaltenes, naphthene and Polar Aromatics, and saturates, respectively. Between −10°C and −30°C, atomic force microscopy images revealed topographic features not visible in atomic force microscopy images acquired at room temperature. According to phase detection microscopy and Tgs, the features were assigned to viscous unfrozen saturates. Upon cooling to −72°C, unfrozen domains of 20–400 nm were observed. These domains were found in the paraphase rich in saturates and in the periphase rich in naphthene Aromatics and Polar Aromatics. The findings indicate that new viscous domains form upon cooling to low temperatures owing to phase segregation, and that some bitumens are never entirely rigid in low temperatures.

  • Low-temperature bitumen stiffness and viscous paraffinic nano- and micro-domains by cryogenic AFM and PDM
    Journal of Microscopy, 2007
    Co-Authors: J-f Masson, V Leblond, J Margeson, Slaðana Bundalo-perc
    Abstract:

    In an effort to better understand the structure and behaviour of bitumen in low temperature, we describe the first use of cryogenic atomic force microscopy and phase detection microscopy to characterize bitumen nano- and micro-structures. The results were interpreted in light of glass transition temperatures (T(g)s) for bitumen fractions. The domains visible by microscopy, the catana, peri and para phases, were attributed to domains rich in asphaltenes, naphthene and Polar Aromatics, and saturates, respectively. Between -10 degrees C and -30 degrees C, atomic force microscopy images revealed topographic features not visible in atomic force microscopy images acquired at room temperature. According to phase detection microscopy and T(g)s, the features were assigned to viscous unfrozen saturates. Upon cooling to -72 degrees C, unfrozen domains of 20-400 nm were observed. These domains were found in the paraphase rich in saturates and in the periphase rich in naphthene Aromatics and Polar Aromatics. The findings indicate that new viscous domains form upon cooling to low temperatures owing to phase segregation, and that some bitumens are never entirely rigid in low temperatures.

  • Bitumen morphologies by phase-detection atomic force microscopy.
    Journal of microscopy, 2006
    Co-Authors: J-f Masson, V Leblond, J Margeson
    Abstract:

    Summary Bitumen is a complex mixture of hydrocarbons for which microstructural knowledge is incomplete. In an effort to detail this microstructure, 13 bitumens were analysed by phase-detection atomic force microscopy. Based on morphology, the bitumens could be classified into three distinct groups. One group showed fine domains down to 0.1 microm, another showed domains of about 1 microm, and a third group showed up to four different domains or phases of different sizes and shapes. No correlation was found between the atomic force microscopy morphology and the composition based on asphaltenes, Polar Aromatics, naphthene Aromatics and saturates. A high correlation was found between the area of the 'bee-like' structures and the vanadium and nickel content in bitumen, and between the atomic force microscopy groups and the average size of molecular planes made of fused Aromatics. The morphology and the molecular arrangements in bitumen thus appear to be partly governed by the molecular planes and the Polarity defined by metallic cations.