The Experts below are selected from a list of 6120 Experts worldwide ranked by ideXlab platform
C. Mirodatos - One of the best experts on this subject based on the ideXlab platform.
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NO Adsorption and Reaction on Aged Pd-Rh Natural Gas Vehicle Catalysts: A Combined TAP and Steady-State Kinetic Approach
Topics in Catalysis, 2017Co-Authors: P. Granger, Y. Reneme, F. Dhainaut, Y. Schuurman, C. MirodatosAbstract:A combined temporal analysis of products (TAP) and steady-state kinetic study was achieved to characterize the surface reactivity of fresh and aged bimetallic Pd-Rh/Al2O3 Natural-Gas Vehicle catalysts. Single NO pulse TAP experiments were performed on a stabilized surface after exposure to successive NO pulses until to get a steady-state NO conversion. Outlet flow curves recorded during such experiments show fast reaction steps taking place on noble metal particles and a slow process during NO desorption ascribed to the involvement of spill-over effect of chemisorbed NO molecules from the metal to the support. This slow process attenuates on the aged sample likely due to an alteration of the metal/support interface induced by particle sintering at high temperature. Thermal aging also alters the surface composition of bimetallic Pd-Rh particles which leads to changes in the products distribution from NO dissociation. A similar selectivity behavior is observed from steady-state kinetic measurements during the NO/H-2 reaction. Interestingly, a weak partial pressure dependency of the selectivity reflects a surface Rh enrichment of Pd-Rh particles during aging.
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comparative surface analysis and tap measurements to probe the no adsorptive properties of Natural Gas Vehicle pd rh al2o3 catalyst
Applied Catalysis B-environmental, 2014Co-Authors: Y. Reneme, F. Dhainaut, Y. Schuurman, C. Mirodatos, Pascal GrangerAbstract:Abstract Thermal ageing has a significant detrimental effect on the behavior of bimetallic Pd–Rh Natural Gas fuelled Vehicle (NGV) catalysts toward NO adsorption and its dissociation recognized as structure-sensitive. The ageing procedure at the lab-scale consisted of a thermal treatment under wet atmosphere (10 vol.% H2O in air) at 980 °C that would induce comparable surface reconstructions taking place under real exhaust conditions of Pd–Rh/Al2O3 catalysts. XPS and FTIR of CO adsorption highlight the occurrence of simultaneous particle sintering and preferential surface Rh enrichment. Temporal analysis of product (TAP) experiments have been implemented for in situ characterization that allows the elucidation of surface reactions and diffusion processes taking place at the surface of Pd–Rh/Al2O3 when single NO pulse is introduced. It was found that the relative rates of those processes are strongly affected by the dispersion and the Rh composition on freshly-prepared and aged catalysts. Interestingly, Rh recognized as the most suitable noble metal to convert NO to N2 would also slow down the agglomeration on Pd further protecting the metal/support interface.
Hamid Reza Rahbari - One of the best experts on this subject based on the ideXlab platform.
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studying transmission of fuel storage bank to ngv cylinder in cng fast filling station
Journal of The Brazilian Society of Mechanical Sciences and Engineering, 2012Co-Authors: Mahdi Deymidashtebayaz, Mahmood Farzaneh Gord, Hamid Reza RahbariAbstract:The exact modeling of the fast-fill process of Compressed Natural Gas (CNG) fueled storage bank occurring to Compressed Natural Gas Vehicle (NGV) cylinders is an unintelligible process, and should be thoroughly studied. In this paper, a theoretical model based on mass balance and thermodynamic laws has been developed to study dynamic fast filling process of CNG storage bank to Vehicle’s (NGV) cylinder. Because Methane occupies a large percentage (between 70% to 99%) of Natural Gas, for the sake of simplicity it is assumed that Methane is the only substance in Natural Gas and thermodynamic properties table has been employed for case of real Gas model based on methane. For modeling the heat transfer, the system has been treated as an adiabatic lump one. The result shows the initial pressure of storage bank has a big effect on the storage bank volume for bringing up the NGV cylinder to its target pressure (20 MPa). The storage bank volumes required for bringing up the NGV cylinder to its final (target) pressure (20 MPa) for various initial storage bank pressure, like 20.8 MPa (RPS = 1.04), 23 MPa (RPS = 1.15) and 25 MPa (RPS = 1.25) are respectively 22, 6 and 4 times the NGV cylinder volume. It is noted that RPS is the ratio of storage bank pressure (PS) to target pressure (PT) (In this research is 20 MPa). The results also showed that ambient temperature has a big effect on refueling process, chiefly on final NGV cylinder and storage bank conditions. Keywords: compressed Natural Gas, NGV cylinder, storage bank, fast filling process, thermodynamic analysis, entropy generation
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Studying transmission of fuel storage bank to NGV cylinder in CNG fast filling station
Journal of The Brazilian Society of Mechanical Sciences and Engineering, 2012Co-Authors: Deymi-dashtebayaz, Mahmood Farzaneh Gord, Hamid Reza RahbariAbstract:The exact modeling of the fast-fill process of Compressed Natural Gas (CNG) fueled storage bank occurring to Compressed Natural Gas Vehicle (NGV) cylinders is an unintelligible process, and should be thoroughly studied. In this paper, a theoretical model based on mass balance and thermodynamic laws has been developed to study dynamic fast filling process of CNG storage bank to Vehicle's (NGV) cylinder. Because Methane occupies a large percentage (between 70% to 99%) of Natural Gas, for the sake of simplicity it is assumed that Methane is the only substance in Natural Gas and thermodynamic properties table has been employed for case of real Gas model based on methane. For modeling the heat transfer, the system has been treated as an adiabatic lump one. The result shows the initial pressure of storage bank has a big effect on the storage bank volume for bringing up the NGV cylinder to its target pressure (20 MPa). The storage bank volumes required for bringing up the NGV cylinder to its final (target) pressure (20 MPa) for various initial storage bank pressure, like 20.8 MPa (RPS = 1.04), 23 MPa (RPS = 1.15) and 25 MPa (RPS = 1.25) are respectively 22, 6 and 4 times the NGV cylinder volume. It is noted that RPS is the ratio of storage bank pressure (PS) to target pressure (PT) (In this research is 20 MPa). The results also showed that ambient temperature has a big effect on refueling process, chiefly on final NGV cylinder and storage bank conditions.
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studying effects of storage types on performance of cng filling stations
Journal of Natural Gas Science and Engineering, 2011Co-Authors: Mahmood Farzanehgord, Mahdi Deymidashtebayaz, Hamid Reza RahbariAbstract:Abstract At CNG filling station, compressed Natural Gas must be stored in storage system in order to make the utilization of the station more efficient. There are two systems for storing Natural Gas namely buffer and cascade storage systems. In buffer storage, CNG is stored at single high-pressure reservoirs. The cascade storage system is usually divided into three reservoirs, generally termed low, medium and high-pressure reservoirs. In current study, based on first and second laws of thermodynamics, conversation of mass and real Gas assumptions, a theoretical analysis has been developed to study effects of reservation type on performance of CNG filling stations and filling process. Considering the same final Natural Gas Vehicle cylinder (NGV) on-board in-cylinder pressure for both storage systems, the results show that each storage type has advantages over the other. The best configuration should be selected by balancing these advantages.
Pascal Granger - One of the best experts on this subject based on the ideXlab platform.
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comparative surface analysis and tap measurements to probe the no adsorptive properties of Natural Gas Vehicle pd rh al2o3 catalyst
Applied Catalysis B-environmental, 2014Co-Authors: Y. Reneme, F. Dhainaut, Y. Schuurman, C. Mirodatos, Pascal GrangerAbstract:Abstract Thermal ageing has a significant detrimental effect on the behavior of bimetallic Pd–Rh Natural Gas fuelled Vehicle (NGV) catalysts toward NO adsorption and its dissociation recognized as structure-sensitive. The ageing procedure at the lab-scale consisted of a thermal treatment under wet atmosphere (10 vol.% H2O in air) at 980 °C that would induce comparable surface reconstructions taking place under real exhaust conditions of Pd–Rh/Al2O3 catalysts. XPS and FTIR of CO adsorption highlight the occurrence of simultaneous particle sintering and preferential surface Rh enrichment. Temporal analysis of product (TAP) experiments have been implemented for in situ characterization that allows the elucidation of surface reactions and diffusion processes taking place at the surface of Pd–Rh/Al2O3 when single NO pulse is introduced. It was found that the relative rates of those processes are strongly affected by the dispersion and the Rh composition on freshly-prepared and aged catalysts. Interestingly, Rh recognized as the most suitable noble metal to convert NO to N2 would also slow down the agglomeration on Pd further protecting the metal/support interface.
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Steady-state and unsteady-state kinetic approaches for studying reactions over three-way Natural Gas Vehicle catalysts
Comptes Rendus Chimie, 2014Co-Authors: Pascal Granger, Stan PietrzykAbstract:Kinetics has been proven to be a powerful method to probe catalytic surfaces under reaction conditions in order to elucidate, at molecular level, complex chemical processes. Numerous techniques and methodologies have been already implemented (surface science approaches, TAP, SSITKA...) running in very different pressure ranges (pressure gap) which led to controversial statements regarding suggested mechanism schemes, especially for DeNOxreactions. Two typical reactions taking place over NGV catalysts have been selected to illustrate which information can be tackled from kinetic measurements. Both reactions occur in different temperature ranges and are sensitive to the structure of the catalyst, to the surface composition of bimetallic particles, with possible surface enrichments, and to the participation of the support. Hence, it will be tentatively demonstrated that kinetic combined with spectroscopic or theoretical methods can be appropriate to establish relevant correlations between kinetic parameters and the topology of the catalyst surface.
F. Dhainaut - One of the best experts on this subject based on the ideXlab platform.
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NO Adsorption and Reaction on Aged Pd-Rh Natural Gas Vehicle Catalysts: A Combined TAP and Steady-State Kinetic Approach
Topics in Catalysis, 2017Co-Authors: P. Granger, Y. Reneme, F. Dhainaut, Y. Schuurman, C. MirodatosAbstract:A combined temporal analysis of products (TAP) and steady-state kinetic study was achieved to characterize the surface reactivity of fresh and aged bimetallic Pd-Rh/Al2O3 Natural-Gas Vehicle catalysts. Single NO pulse TAP experiments were performed on a stabilized surface after exposure to successive NO pulses until to get a steady-state NO conversion. Outlet flow curves recorded during such experiments show fast reaction steps taking place on noble metal particles and a slow process during NO desorption ascribed to the involvement of spill-over effect of chemisorbed NO molecules from the metal to the support. This slow process attenuates on the aged sample likely due to an alteration of the metal/support interface induced by particle sintering at high temperature. Thermal aging also alters the surface composition of bimetallic Pd-Rh particles which leads to changes in the products distribution from NO dissociation. A similar selectivity behavior is observed from steady-state kinetic measurements during the NO/H-2 reaction. Interestingly, a weak partial pressure dependency of the selectivity reflects a surface Rh enrichment of Pd-Rh particles during aging.
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comparative surface analysis and tap measurements to probe the no adsorptive properties of Natural Gas Vehicle pd rh al2o3 catalyst
Applied Catalysis B-environmental, 2014Co-Authors: Y. Reneme, F. Dhainaut, Y. Schuurman, C. Mirodatos, Pascal GrangerAbstract:Abstract Thermal ageing has a significant detrimental effect on the behavior of bimetallic Pd–Rh Natural Gas fuelled Vehicle (NGV) catalysts toward NO adsorption and its dissociation recognized as structure-sensitive. The ageing procedure at the lab-scale consisted of a thermal treatment under wet atmosphere (10 vol.% H2O in air) at 980 °C that would induce comparable surface reconstructions taking place under real exhaust conditions of Pd–Rh/Al2O3 catalysts. XPS and FTIR of CO adsorption highlight the occurrence of simultaneous particle sintering and preferential surface Rh enrichment. Temporal analysis of product (TAP) experiments have been implemented for in situ characterization that allows the elucidation of surface reactions and diffusion processes taking place at the surface of Pd–Rh/Al2O3 when single NO pulse is introduced. It was found that the relative rates of those processes are strongly affected by the dispersion and the Rh composition on freshly-prepared and aged catalysts. Interestingly, Rh recognized as the most suitable noble metal to convert NO to N2 would also slow down the agglomeration on Pd further protecting the metal/support interface.
Y. Reneme - One of the best experts on this subject based on the ideXlab platform.
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NO Adsorption and Reaction on Aged Pd-Rh Natural Gas Vehicle Catalysts: A Combined TAP and Steady-State Kinetic Approach
Topics in Catalysis, 2017Co-Authors: P. Granger, Y. Reneme, F. Dhainaut, Y. Schuurman, C. MirodatosAbstract:A combined temporal analysis of products (TAP) and steady-state kinetic study was achieved to characterize the surface reactivity of fresh and aged bimetallic Pd-Rh/Al2O3 Natural-Gas Vehicle catalysts. Single NO pulse TAP experiments were performed on a stabilized surface after exposure to successive NO pulses until to get a steady-state NO conversion. Outlet flow curves recorded during such experiments show fast reaction steps taking place on noble metal particles and a slow process during NO desorption ascribed to the involvement of spill-over effect of chemisorbed NO molecules from the metal to the support. This slow process attenuates on the aged sample likely due to an alteration of the metal/support interface induced by particle sintering at high temperature. Thermal aging also alters the surface composition of bimetallic Pd-Rh particles which leads to changes in the products distribution from NO dissociation. A similar selectivity behavior is observed from steady-state kinetic measurements during the NO/H-2 reaction. Interestingly, a weak partial pressure dependency of the selectivity reflects a surface Rh enrichment of Pd-Rh particles during aging.
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comparative surface analysis and tap measurements to probe the no adsorptive properties of Natural Gas Vehicle pd rh al2o3 catalyst
Applied Catalysis B-environmental, 2014Co-Authors: Y. Reneme, F. Dhainaut, Y. Schuurman, C. Mirodatos, Pascal GrangerAbstract:Abstract Thermal ageing has a significant detrimental effect on the behavior of bimetallic Pd–Rh Natural Gas fuelled Vehicle (NGV) catalysts toward NO adsorption and its dissociation recognized as structure-sensitive. The ageing procedure at the lab-scale consisted of a thermal treatment under wet atmosphere (10 vol.% H2O in air) at 980 °C that would induce comparable surface reconstructions taking place under real exhaust conditions of Pd–Rh/Al2O3 catalysts. XPS and FTIR of CO adsorption highlight the occurrence of simultaneous particle sintering and preferential surface Rh enrichment. Temporal analysis of product (TAP) experiments have been implemented for in situ characterization that allows the elucidation of surface reactions and diffusion processes taking place at the surface of Pd–Rh/Al2O3 when single NO pulse is introduced. It was found that the relative rates of those processes are strongly affected by the dispersion and the Rh composition on freshly-prepared and aged catalysts. Interestingly, Rh recognized as the most suitable noble metal to convert NO to N2 would also slow down the agglomeration on Pd further protecting the metal/support interface.
