The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Masaru Ichikawa - One of the best experts on this subject based on the ideXlab platform.
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Thermal imaging of Catalyst Surface during catalytic dehydrogenation of cyclohexane under spray-pulsed conditions
Chemical Engineering Science, 2007Co-Authors: Rajesh B. Biniwale, Masaru IchikawaAbstract:Infra-red thermographic imaging, a tool widely used for screening of active catalytic materials in the field of combinatorial chemistry, has been used during dehydrogenation of cyclohexane on Pt Catalyst supported on active carbon cloth and alumite supports. A spray-pulsed reactor with injection of atomized cyclohexane and to create alternate wet and dry conditions on the Catalyst Surface was used in this study. Since the production rate of hydrogen via endothermic dehydrogenation reaction is greatly dependent on the temperature of the Catalyst Surface, the temperature profile of the Catalyst is important to observe. The observed change in the temperature profile at wet and dry conditions with varying pulse injection frequency and corresponding product gas analysis reveals that the spray-pulse mode is useful in improving the Catalyst activity. Further, the comparison between activated carbon support and a more conductive support such as alumite is reported using thermal imaging for more suitable support in this endothermic reaction.
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Heat transfer and thermographic analysis of Catalyst Surface during multiphase phenomena under spray-pulsed conditions for dehydrogenation of cyclohexane over Pt Catalysts.
The journal of physical chemistry. B, 2006Co-Authors: Rajesh B. Biniwale, Nobuko Kariya, Hikaru Yamashiro, Masaru IchikawaAbstract:Dehydrogenation of cyclohexane over Pt/alumite and Pt/activated carbon Catalysts has been carried out for hydrogen storage and supply to fuel cell applications. An unsteady state has been created using spray pulsed injection of cyclohexane over the Catalyst Surface to facilitate the endothermic reaction to occur efficiently. Higher temperature of the Catalyst Surface is more favorable for the reaction, thus the heat transfer phenomena and temperature profile under alternate wet and dry conditions created using spray pulsed injection becomes important. IR thermography has been used for monitoring of temperature profile of the Catalyst Surface simultaneously with product analysis. The heat flux from the plate-type heater to the Catalyst has been estimated using a rapid temperature recording and thermocouple arrangement. The estimated heat flux under transient conditions was in the range of 10−15 kW/m2, which equates the requirement for endothermic reactions to the injection frequency of 0.5 Hz, as used in t...
Anwar Hossaen - One of the best experts on this subject based on the ideXlab platform.
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Apparent kinetics of nonisothermal high temperature oxidative degradation of ethylene homopolymers: effects of residual Catalyst Surface chemistry and structure
Journal of Polymer Research, 2013Co-Authors: Muhammad Atiqullah, Hasan A. Al-muallem, Abdulrahman F. Alharbi, Ikram Hussain, Khurshid Alam, Syed Masiur Rahman, Mohammad M Hossain, Anwar HossaenAbstract:The effects of two supported residual Catalysts—one Ziegler-Natta and another metallocene—on the nonisothermal thermooxidative degradation of the resulting ethylene homopolymers were investigated using TGA experiments and kinetic modeling. The rigorous constitutive kinetic model (developed in this study), unlike the analytical Horowitz and Metzger model, fitted very well to the entire TGA curve, without distribution of activation energy E _ a , for n (overall degradation order) = 1 for both polymers. Neither n nor E _ a varied as a function of fractional weight loss of the polymer. Hence, the proposed unified molecular level concept of Surface chemistry and structure of the residual Catalysts held all through the degradation process. The above feature of n and E _ a also indicates the suitability of the model formulation and the effectiveness of the parameter-estimation algorithm. Random polymer chain scission, with the cleavage of the −C−C− and the −O−O− (hydroperoxide) bonds, prevailed. The types of residual Catalyst Surface chemistry and structure varied the bond cleavage process. The metallocene Zr residual Catalyst caused more thermooxidative degradation in MetCat HomoPE than what the Ti one did in Z-N HomoPE. The rigorous constitutive model-predicted apparent kinetic energy E _ a , and frequency factor Z also support this finding. The proposed degradation mechanism suggests that the Zr residual Catalyst more (i) decreased the activation energy required to decompose the −C−C− and the −O−O− bonds, and (ii) eliminated β-hydrogen (by the carbonyl functionalities) from the polymer chains. These findings were attributed to the differences in Surface chemistry and structure of the residual Catalysts. Therefore, the current study presents a rigorous constitutive kinetic model that duly illustrates the influence of the characteristic Surface chemistry and structure of the residual Catalysts on the high temperature oxidative degradation of polyethylenes.
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Apparent kinetics of nonisothermal high temperature oxidative degradation of ethylene homopolymers: effects of residual Catalyst Surface chemistry and structure
Journal of Polymer Research, 2013Co-Authors: Muhammad Atiqullah, Hasan A. Al-muallem, Abdulrahman F. Alharbi, Ikram Hussain, Khurshid Alam, Syed Masiur Rahman, Mohammad M Hossain, Anwar HossaenAbstract:The effects of two supported residual Catalysts—one Ziegler-Natta and another metallocene—on the nonisothermal thermooxidative degradation of the resulting ethylene homopolymers were investigated using TGA experiments and kinetic modeling. The rigorous constitutive kinetic model (developed in this study), unlike the analytical Horowitz and Metzger model, fitted very well to the entire TGA curve, without distribution of activation energy E _ a , for n (overall degradation order) = 1 for both polymers. Neither n nor E _ a varied as a function of fractional weight loss of the polymer. Hence, the proposed unified molecular level concept of Surface chemistry and structure of the residual Catalysts held all through the degradation process. The above feature of n and E _ a also indicates the suitability of the model formulation and the effectiveness of the parameter-estimation algorithm. Random polymer chain scission, with the cleavage of the −C−C− and the −O−O− (hydroperoxide) bonds, prevailed. The types of residual Catalyst Surface chemistry and structure varied the bond cleavage process. The metallocene Zr residual Catalyst caused more thermooxidative degradation in MetCat HomoPE than what the Ti one did in Z-N HomoPE. The rigorous constitutive model-predicted apparent kinetic energy E _ a , and frequency factor Z also support this finding. The proposed degradation mechanism suggests that the Zr residual Catalyst more (i) decreased the activation energy required to decompose the −C−C− and the −O−O− bonds, and (ii) eliminated β-hydrogen (by the carbonyl functionalities) from the polymer chains. These findings were attributed to the differences in Surface chemistry and structure of the residual Catalysts. Therefore, the current study presents a rigorous constitutive kinetic model that duly illustrates the influence of the characteristic Surface chemistry and structure of the residual Catalysts on the high temperature oxidative degradation of polyethylenes.
Rajesh B. Biniwale - One of the best experts on this subject based on the ideXlab platform.
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Thermal imaging of Catalyst Surface during catalytic dehydrogenation of cyclohexane under spray-pulsed conditions
Chemical Engineering Science, 2007Co-Authors: Rajesh B. Biniwale, Masaru IchikawaAbstract:Infra-red thermographic imaging, a tool widely used for screening of active catalytic materials in the field of combinatorial chemistry, has been used during dehydrogenation of cyclohexane on Pt Catalyst supported on active carbon cloth and alumite supports. A spray-pulsed reactor with injection of atomized cyclohexane and to create alternate wet and dry conditions on the Catalyst Surface was used in this study. Since the production rate of hydrogen via endothermic dehydrogenation reaction is greatly dependent on the temperature of the Catalyst Surface, the temperature profile of the Catalyst is important to observe. The observed change in the temperature profile at wet and dry conditions with varying pulse injection frequency and corresponding product gas analysis reveals that the spray-pulse mode is useful in improving the Catalyst activity. Further, the comparison between activated carbon support and a more conductive support such as alumite is reported using thermal imaging for more suitable support in this endothermic reaction.
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Heat transfer and thermographic analysis of Catalyst Surface during multiphase phenomena under spray-pulsed conditions for dehydrogenation of cyclohexane over Pt Catalysts.
The journal of physical chemistry. B, 2006Co-Authors: Rajesh B. Biniwale, Nobuko Kariya, Hikaru Yamashiro, Masaru IchikawaAbstract:Dehydrogenation of cyclohexane over Pt/alumite and Pt/activated carbon Catalysts has been carried out for hydrogen storage and supply to fuel cell applications. An unsteady state has been created using spray pulsed injection of cyclohexane over the Catalyst Surface to facilitate the endothermic reaction to occur efficiently. Higher temperature of the Catalyst Surface is more favorable for the reaction, thus the heat transfer phenomena and temperature profile under alternate wet and dry conditions created using spray pulsed injection becomes important. IR thermography has been used for monitoring of temperature profile of the Catalyst Surface simultaneously with product analysis. The heat flux from the plate-type heater to the Catalyst has been estimated using a rapid temperature recording and thermocouple arrangement. The estimated heat flux under transient conditions was in the range of 10−15 kW/m2, which equates the requirement for endothermic reactions to the injection frequency of 0.5 Hz, as used in t...
Edwin L. Kugler - One of the best experts on this subject based on the ideXlab platform.
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Visualization of the equilibrium FCC Catalyst Surface by AFM and SEM-EDS
Catalysis Letters, 2003Co-Authors: Oguz Bayraktar, Edwin L. KuglerAbstract:The deposition of metal contaminants (e.g., Ni, V, and Fe) from the hydrocarbon feed causes the deactivation of fluid catalytic cracking (FCC) Catalyst used in petroleum refining. It is very important to understand the changes in the morphology and chemical composition on the Catalyst Surface and how these structural and chemical changes affect the Catalyst performance. In this research, metal-contaminated FCC Catalysts from a commercial unit have been characterized using AFM together with SEM–EDS. The AFM images showed the Surface pores as well as the features that surround the pore's entrance on the Catalyst Surface. Catalyst Surface contains debris that appear as bright spots in AFM images. SEM–EDS results have shown the presence of iron in these bright spots. Fe enrichment at the Catalyst particle Surface was also confirmed by XPS analyses.
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Visualization of the Equilibrium FCC Catalyst Surface by AFM and SEM–EDS
Catalysis Letters, 2003Co-Authors: Oguz Bayraktar, Edwin L. KuglerAbstract:The deposition of metal contaminants (e.g., Ni, V, and Fe) from the hydrocarbon feed causes the deactivation of fluid catalytic cracking (FCC) Catalyst used in petroleum refining. It is very important to understand the changes in the morphology and chemical composition on the Catalyst Surface and how these structural and chemical changes affect the Catalyst performance. In this research, metal-contaminated FCC Catalysts from a commercial unit have been characterized using AFM together with SEM-EDS. The AFM images showed the Surface pores as well as the features that surround the pore's entrance on the Catalyst Surface. Catalyst Surface contains debris that appear as bright spots in AFM images. SEM-EDS results have shown the presence of iron in these bright spots. Fe enrichment at the Catalyst particle Surface was also confirmed by XPS analyses
Muhammad Atiqullah - One of the best experts on this subject based on the ideXlab platform.
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Apparent kinetics of nonisothermal high temperature oxidative degradation of ethylene homopolymers: effects of residual Catalyst Surface chemistry and structure
Journal of Polymer Research, 2013Co-Authors: Muhammad Atiqullah, Hasan A. Al-muallem, Abdulrahman F. Alharbi, Ikram Hussain, Khurshid Alam, Syed Masiur Rahman, Mohammad M Hossain, Anwar HossaenAbstract:The effects of two supported residual Catalysts—one Ziegler-Natta and another metallocene—on the nonisothermal thermooxidative degradation of the resulting ethylene homopolymers were investigated using TGA experiments and kinetic modeling. The rigorous constitutive kinetic model (developed in this study), unlike the analytical Horowitz and Metzger model, fitted very well to the entire TGA curve, without distribution of activation energy E _ a , for n (overall degradation order) = 1 for both polymers. Neither n nor E _ a varied as a function of fractional weight loss of the polymer. Hence, the proposed unified molecular level concept of Surface chemistry and structure of the residual Catalysts held all through the degradation process. The above feature of n and E _ a also indicates the suitability of the model formulation and the effectiveness of the parameter-estimation algorithm. Random polymer chain scission, with the cleavage of the −C−C− and the −O−O− (hydroperoxide) bonds, prevailed. The types of residual Catalyst Surface chemistry and structure varied the bond cleavage process. The metallocene Zr residual Catalyst caused more thermooxidative degradation in MetCat HomoPE than what the Ti one did in Z-N HomoPE. The rigorous constitutive model-predicted apparent kinetic energy E _ a , and frequency factor Z also support this finding. The proposed degradation mechanism suggests that the Zr residual Catalyst more (i) decreased the activation energy required to decompose the −C−C− and the −O−O− bonds, and (ii) eliminated β-hydrogen (by the carbonyl functionalities) from the polymer chains. These findings were attributed to the differences in Surface chemistry and structure of the residual Catalysts. Therefore, the current study presents a rigorous constitutive kinetic model that duly illustrates the influence of the characteristic Surface chemistry and structure of the residual Catalysts on the high temperature oxidative degradation of polyethylenes.
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Apparent kinetics of nonisothermal high temperature oxidative degradation of ethylene homopolymers: effects of residual Catalyst Surface chemistry and structure
Journal of Polymer Research, 2013Co-Authors: Muhammad Atiqullah, Hasan A. Al-muallem, Abdulrahman F. Alharbi, Ikram Hussain, Khurshid Alam, Syed Masiur Rahman, Mohammad M Hossain, Anwar HossaenAbstract:The effects of two supported residual Catalysts—one Ziegler-Natta and another metallocene—on the nonisothermal thermooxidative degradation of the resulting ethylene homopolymers were investigated using TGA experiments and kinetic modeling. The rigorous constitutive kinetic model (developed in this study), unlike the analytical Horowitz and Metzger model, fitted very well to the entire TGA curve, without distribution of activation energy E _ a , for n (overall degradation order) = 1 for both polymers. Neither n nor E _ a varied as a function of fractional weight loss of the polymer. Hence, the proposed unified molecular level concept of Surface chemistry and structure of the residual Catalysts held all through the degradation process. The above feature of n and E _ a also indicates the suitability of the model formulation and the effectiveness of the parameter-estimation algorithm. Random polymer chain scission, with the cleavage of the −C−C− and the −O−O− (hydroperoxide) bonds, prevailed. The types of residual Catalyst Surface chemistry and structure varied the bond cleavage process. The metallocene Zr residual Catalyst caused more thermooxidative degradation in MetCat HomoPE than what the Ti one did in Z-N HomoPE. The rigorous constitutive model-predicted apparent kinetic energy E _ a , and frequency factor Z also support this finding. The proposed degradation mechanism suggests that the Zr residual Catalyst more (i) decreased the activation energy required to decompose the −C−C− and the −O−O− bonds, and (ii) eliminated β-hydrogen (by the carbonyl functionalities) from the polymer chains. These findings were attributed to the differences in Surface chemistry and structure of the residual Catalysts. Therefore, the current study presents a rigorous constitutive kinetic model that duly illustrates the influence of the characteristic Surface chemistry and structure of the residual Catalysts on the high temperature oxidative degradation of polyethylenes.