The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
K J Huttinger - One of the best experts on this subject based on the ideXlab platform.
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Determination of the kinetics of CVD in hot wall Reactors
Chemical Vapor Deposition, 2000Co-Authors: Z J Hu, K J HuttingerAbstract:CVD of pyrolytic carbon from methane was studied as a model reaction to demonstrate the influence on deposition kinetics of the variation of i) the Volume flow rate (leading to different initial conditions) and ii) the substrate surface area, or substrate surface area/Reactor Volume ratio (third parameter of CVD). The experiments were performed at an ambient pressure of about 100 kPa, a methane partial pressure of 10 kPa, and a temperature of 1100°C. Carbon deposition rates as a function of Reactor/substrate length were studied at three different Volume flows, or total residence times, using three substrates with different surface area/Reactor Volume ratios, (A S /V R ). Additionally, compositions of the gas phase were determined. Changing the Volume flow leads not only to different initial conditions but also to different deposition rates as a function of residence time, in contrast to a homogeneous reaction. Experiments with substrates exhibiting different A S /V R ratios confirm earlier results that a broad variety of deposition kinetics can be obtained by changing this ratio.
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chemical vapour deposition in hot wall Reactors the role of the ratio of substrate surface area to Reactor Volume
High Temperatures-high Pressures, 2000Co-Authors: M Teubner, Z J Hu, K J HuttingerAbstract:The deposition of pyrolytic carbon from methane has been used to investigate the influence of the ratio of substrate surface area to Reactor Volume, A S /V R , on deposition chemistry and kinetics. Deposition studies were performed at a pressure of about 100 kPa (ambient pressure), a methane partial pressure of 10 kPa, and a temperature of 1100 °C. The A S /V R ratio was varied from 0.18 to 8.2 mm -1 . Carbon deposition rates and corresponding compositions of the gas phase were determined as a function of residence time. The experimental results show Volume-related carbon formation rates increasing with increasing surface area or increasing A S /V R ratio, but surface-related carbon deposition rates decreasing with increasing surface area or increasing ratio. The latter result implies that any kinetics of chemical vapour deposition determined in the past are only valid for the reaction system used.
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the role of the substrate surface area Reactor Volume ratio in chemistry and kinetics of chemical vapor deposition
Journal De Physique Iv, 1999Co-Authors: M Teubner, J Antes, Z J Hu, W G Zhang, K J HuttingerAbstract:Chemical vapor deposition of carbon from methane was used as a test reaction to investigate the influence of the substrate surface area/Reactor Volume ratio, [A S /V R ], on the deposition kinetics. Experiments were performed at an ambient pressure of about 100 kPa and a temperature of 1100 °C using methane at a partial pressure of 10 kPa and a methane/hydrogen mixture (P CH4 =17.5kPa, P H2 =2.5kPa). The [A S /V R ]-ratio was varied from 1.8 to 10, 20, 40 and 80 cm -1 . It is shown that surface related deposition rates are not constant, but decrease with increasing [A S /V R ]-ratio. This result indicates that any kinetics can be determined by changing this ratio, which is called the third parameter of CVD. Consequences are discussed.
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The role of the substrate surface area/Reactor Volume ratio in chemistry and kinetics of chemical vapor deposition
Journal De Physique Iv, 1999Co-Authors: M Teubner, J Antes, Z J Hu, W G Zhang, K J HuttingerAbstract:Chemical vapor deposition of carbon from methane was used as a test reaction to investigate the influence of the substrate surface area/Reactor Volume ratio, [A S /V R ], on the deposition kinetics. Experiments were performed at an ambient pressure of about 100 kPa and a temperature of 1100 °C using methane at a partial pressure of 10 kPa and a methane/hydrogen mixture (P CH4 =17.5kPa, P H2 =2.5kPa). The [A S /V R ]-ratio was varied from 1.8 to 10, 20, 40 and 80 cm -1 . It is shown that surface related deposition rates are not constant, but decrease with increasing [A S /V R ]-ratio. This result indicates that any kinetics can be determined by changing this ratio, which is called the third parameter of CVD. Consequences are discussed.
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Chemistry and kinetics of chemical vapour deposition of pyrocarbon: VII. Confirmation of the influence of the substrate surface area/Reactor Volume ratio
Carbon, 1999Co-Authors: J Antes, Z J Hu, W G Zhang, K J HuttingerAbstract:Abstract Carbon deposition from a methane–hydrogen mixture ( p CH 4 =17.5 kPa, p H 2 =2.5 kPa) was studied at an ambient pressure of about 100 kPa and a temperature of 1100°C, using deposition arrangements with surface area/Reactor Volume ratios, [ A S / V R ], of 10, 20, 40 and 80 cm −1 . Steady-state deposition rates and corresponding compositions of the gas phase as a function of residence were determined. The deposition rates in mol/h increase with increasing [ A S / V R ] ratio at all investigated residence times up to 1 s. However, surface-related deposition rates in mol/m 2 h decreased. As the same results have been obtained in a preceding study using pure methane at a partial pressure of 10 kPa, it has been confirmed that all the kinetics can be determined by changing the [ A S / V R ] ratio.
Thomas Turek - One of the best experts on this subject based on the ideXlab platform.
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Comparison of different Reactor types for low temperature Fischer–Tropsch synthesis: A simulation study
Chemical Engineering Science, 2009Co-Authors: Robert Guettel, Thomas TurekAbstract:Abstract The commercially established slurry bubble column and fixed-bed Reactors for low temperature Fischer–Tropsch synthesis were compared with novel micro- and monolith-Reactors by mathematical modeling. Special attention was paid to the influence of catalytic activity on the Reactor efficiency and the losses by mass and heat transfer resistances. The simulation results show that a micro-structured Reactor exhibits the highest productivity per unit of catalyst Volume followed by slurry bubble column Reactor and monolith Reactor. The fixed-bed Reactor that was assumed to operate in the trickle-flow regime has a particularly low catalyst specific productivity due to severe mass transfer resistances. However, caused by a very low ratio of catalyst and Reactor Volume the micro-Reactor has only a similarly low productivity per unit of Reactor Volume as the fixed-bed Reactor. In contrast, the Reactor specific productivity of slurry bubble column Reactor and monolith Reactor is up to one order of magnitude higher.
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Comparison of different Reactor types for low temperature Fischer-Tropsch synthesis: A simulation study
Chemical Engineering Science, 2009Co-Authors: Robert Guettel, Thomas TurekAbstract:The commercially established slurry bubble column and fixed-bed Reactors for low temperature Fischer-Tropsch synthesis were compared with novel micro- and monolith-Reactors by mathematical modeling. Special attention was paid to the influence of catalytic activity on the Reactor efficiency and the losses by mass and heat transfer resistances. The simulation results show that a micro-structured Reactor exhibits the highest productivity per unit of catalyst Volume followed by slurry bubble column Reactor and monolith Reactor. The fixed-bed Reactor that was assumed to operate in the trickle-flow regime has a particularly low catalyst specific productivity due to severe mass transfer resistances. However, caused by a very low ratio of catalyst and Reactor Volume the micro-Reactor has only a similarly low productivity per unit of Reactor Volume as the fixed-bed Reactor. In contrast, the Reactor specific productivity of slurry bubble column Reactor and monolith Reactor is up to one order of magnitude higher. © 2008 Elsevier Ltd. All rights reserved.
Robert Guettel - One of the best experts on this subject based on the ideXlab platform.
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Comparison of different Reactor types for low temperature Fischer–Tropsch synthesis: A simulation study
Chemical Engineering Science, 2009Co-Authors: Robert Guettel, Thomas TurekAbstract:Abstract The commercially established slurry bubble column and fixed-bed Reactors for low temperature Fischer–Tropsch synthesis were compared with novel micro- and monolith-Reactors by mathematical modeling. Special attention was paid to the influence of catalytic activity on the Reactor efficiency and the losses by mass and heat transfer resistances. The simulation results show that a micro-structured Reactor exhibits the highest productivity per unit of catalyst Volume followed by slurry bubble column Reactor and monolith Reactor. The fixed-bed Reactor that was assumed to operate in the trickle-flow regime has a particularly low catalyst specific productivity due to severe mass transfer resistances. However, caused by a very low ratio of catalyst and Reactor Volume the micro-Reactor has only a similarly low productivity per unit of Reactor Volume as the fixed-bed Reactor. In contrast, the Reactor specific productivity of slurry bubble column Reactor and monolith Reactor is up to one order of magnitude higher.
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Comparison of different Reactor types for low temperature Fischer-Tropsch synthesis: A simulation study
Chemical Engineering Science, 2009Co-Authors: Robert Guettel, Thomas TurekAbstract:The commercially established slurry bubble column and fixed-bed Reactors for low temperature Fischer-Tropsch synthesis were compared with novel micro- and monolith-Reactors by mathematical modeling. Special attention was paid to the influence of catalytic activity on the Reactor efficiency and the losses by mass and heat transfer resistances. The simulation results show that a micro-structured Reactor exhibits the highest productivity per unit of catalyst Volume followed by slurry bubble column Reactor and monolith Reactor. The fixed-bed Reactor that was assumed to operate in the trickle-flow regime has a particularly low catalyst specific productivity due to severe mass transfer resistances. However, caused by a very low ratio of catalyst and Reactor Volume the micro-Reactor has only a similarly low productivity per unit of Reactor Volume as the fixed-bed Reactor. In contrast, the Reactor specific productivity of slurry bubble column Reactor and monolith Reactor is up to one order of magnitude higher. © 2008 Elsevier Ltd. All rights reserved.
Z J Hu - One of the best experts on this subject based on the ideXlab platform.
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Determination of the kinetics of CVD in hot wall Reactors
Chemical Vapor Deposition, 2000Co-Authors: Z J Hu, K J HuttingerAbstract:CVD of pyrolytic carbon from methane was studied as a model reaction to demonstrate the influence on deposition kinetics of the variation of i) the Volume flow rate (leading to different initial conditions) and ii) the substrate surface area, or substrate surface area/Reactor Volume ratio (third parameter of CVD). The experiments were performed at an ambient pressure of about 100 kPa, a methane partial pressure of 10 kPa, and a temperature of 1100°C. Carbon deposition rates as a function of Reactor/substrate length were studied at three different Volume flows, or total residence times, using three substrates with different surface area/Reactor Volume ratios, (A S /V R ). Additionally, compositions of the gas phase were determined. Changing the Volume flow leads not only to different initial conditions but also to different deposition rates as a function of residence time, in contrast to a homogeneous reaction. Experiments with substrates exhibiting different A S /V R ratios confirm earlier results that a broad variety of deposition kinetics can be obtained by changing this ratio.
-
chemical vapour deposition in hot wall Reactors the role of the ratio of substrate surface area to Reactor Volume
High Temperatures-high Pressures, 2000Co-Authors: M Teubner, Z J Hu, K J HuttingerAbstract:The deposition of pyrolytic carbon from methane has been used to investigate the influence of the ratio of substrate surface area to Reactor Volume, A S /V R , on deposition chemistry and kinetics. Deposition studies were performed at a pressure of about 100 kPa (ambient pressure), a methane partial pressure of 10 kPa, and a temperature of 1100 °C. The A S /V R ratio was varied from 0.18 to 8.2 mm -1 . Carbon deposition rates and corresponding compositions of the gas phase were determined as a function of residence time. The experimental results show Volume-related carbon formation rates increasing with increasing surface area or increasing A S /V R ratio, but surface-related carbon deposition rates decreasing with increasing surface area or increasing ratio. The latter result implies that any kinetics of chemical vapour deposition determined in the past are only valid for the reaction system used.
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the role of the substrate surface area Reactor Volume ratio in chemistry and kinetics of chemical vapor deposition
Journal De Physique Iv, 1999Co-Authors: M Teubner, J Antes, Z J Hu, W G Zhang, K J HuttingerAbstract:Chemical vapor deposition of carbon from methane was used as a test reaction to investigate the influence of the substrate surface area/Reactor Volume ratio, [A S /V R ], on the deposition kinetics. Experiments were performed at an ambient pressure of about 100 kPa and a temperature of 1100 °C using methane at a partial pressure of 10 kPa and a methane/hydrogen mixture (P CH4 =17.5kPa, P H2 =2.5kPa). The [A S /V R ]-ratio was varied from 1.8 to 10, 20, 40 and 80 cm -1 . It is shown that surface related deposition rates are not constant, but decrease with increasing [A S /V R ]-ratio. This result indicates that any kinetics can be determined by changing this ratio, which is called the third parameter of CVD. Consequences are discussed.
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The role of the substrate surface area/Reactor Volume ratio in chemistry and kinetics of chemical vapor deposition
Journal De Physique Iv, 1999Co-Authors: M Teubner, J Antes, Z J Hu, W G Zhang, K J HuttingerAbstract:Chemical vapor deposition of carbon from methane was used as a test reaction to investigate the influence of the substrate surface area/Reactor Volume ratio, [A S /V R ], on the deposition kinetics. Experiments were performed at an ambient pressure of about 100 kPa and a temperature of 1100 °C using methane at a partial pressure of 10 kPa and a methane/hydrogen mixture (P CH4 =17.5kPa, P H2 =2.5kPa). The [A S /V R ]-ratio was varied from 1.8 to 10, 20, 40 and 80 cm -1 . It is shown that surface related deposition rates are not constant, but decrease with increasing [A S /V R ]-ratio. This result indicates that any kinetics can be determined by changing this ratio, which is called the third parameter of CVD. Consequences are discussed.
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Chemistry and kinetics of chemical vapour deposition of pyrocarbon: VII. Confirmation of the influence of the substrate surface area/Reactor Volume ratio
Carbon, 1999Co-Authors: J Antes, Z J Hu, W G Zhang, K J HuttingerAbstract:Abstract Carbon deposition from a methane–hydrogen mixture ( p CH 4 =17.5 kPa, p H 2 =2.5 kPa) was studied at an ambient pressure of about 100 kPa and a temperature of 1100°C, using deposition arrangements with surface area/Reactor Volume ratios, [ A S / V R ], of 10, 20, 40 and 80 cm −1 . Steady-state deposition rates and corresponding compositions of the gas phase as a function of residence were determined. The deposition rates in mol/h increase with increasing [ A S / V R ] ratio at all investigated residence times up to 1 s. However, surface-related deposition rates in mol/m 2 h decreased. As the same results have been obtained in a preceding study using pure methane at a partial pressure of 10 kPa, it has been confirmed that all the kinetics can be determined by changing the [ A S / V R ] ratio.
J Antes - One of the best experts on this subject based on the ideXlab platform.
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the role of the substrate surface area Reactor Volume ratio in chemistry and kinetics of chemical vapor deposition
Journal De Physique Iv, 1999Co-Authors: M Teubner, J Antes, Z J Hu, W G Zhang, K J HuttingerAbstract:Chemical vapor deposition of carbon from methane was used as a test reaction to investigate the influence of the substrate surface area/Reactor Volume ratio, [A S /V R ], on the deposition kinetics. Experiments were performed at an ambient pressure of about 100 kPa and a temperature of 1100 °C using methane at a partial pressure of 10 kPa and a methane/hydrogen mixture (P CH4 =17.5kPa, P H2 =2.5kPa). The [A S /V R ]-ratio was varied from 1.8 to 10, 20, 40 and 80 cm -1 . It is shown that surface related deposition rates are not constant, but decrease with increasing [A S /V R ]-ratio. This result indicates that any kinetics can be determined by changing this ratio, which is called the third parameter of CVD. Consequences are discussed.
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The role of the substrate surface area/Reactor Volume ratio in chemistry and kinetics of chemical vapor deposition
Journal De Physique Iv, 1999Co-Authors: M Teubner, J Antes, Z J Hu, W G Zhang, K J HuttingerAbstract:Chemical vapor deposition of carbon from methane was used as a test reaction to investigate the influence of the substrate surface area/Reactor Volume ratio, [A S /V R ], on the deposition kinetics. Experiments were performed at an ambient pressure of about 100 kPa and a temperature of 1100 °C using methane at a partial pressure of 10 kPa and a methane/hydrogen mixture (P CH4 =17.5kPa, P H2 =2.5kPa). The [A S /V R ]-ratio was varied from 1.8 to 10, 20, 40 and 80 cm -1 . It is shown that surface related deposition rates are not constant, but decrease with increasing [A S /V R ]-ratio. This result indicates that any kinetics can be determined by changing this ratio, which is called the third parameter of CVD. Consequences are discussed.
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Chemistry and kinetics of chemical vapour deposition of pyrocarbon: VII. Confirmation of the influence of the substrate surface area/Reactor Volume ratio
Carbon, 1999Co-Authors: J Antes, Z J Hu, W G Zhang, K J HuttingerAbstract:Abstract Carbon deposition from a methane–hydrogen mixture ( p CH 4 =17.5 kPa, p H 2 =2.5 kPa) was studied at an ambient pressure of about 100 kPa and a temperature of 1100°C, using deposition arrangements with surface area/Reactor Volume ratios, [ A S / V R ], of 10, 20, 40 and 80 cm −1 . Steady-state deposition rates and corresponding compositions of the gas phase as a function of residence were determined. The deposition rates in mol/h increase with increasing [ A S / V R ] ratio at all investigated residence times up to 1 s. However, surface-related deposition rates in mol/m 2 h decreased. As the same results have been obtained in a preceding study using pure methane at a partial pressure of 10 kPa, it has been confirmed that all the kinetics can be determined by changing the [ A S / V R ] ratio.
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chemistry and kinetics of chemical vapour deposition of pyrocarbon vii confirmation of the influence of the substrate surface area Reactor Volume ratio
Carbon, 1999Co-Authors: J Antes, Z J Hu, W G Zhang, K J HuttingerAbstract:Abstract Carbon deposition from a methane–hydrogen mixture ( p CH 4 =17.5 kPa, p H 2 =2.5 kPa) was studied at an ambient pressure of about 100 kPa and a temperature of 1100°C, using deposition arrangements with surface area/Reactor Volume ratios, [ A S / V R ], of 10, 20, 40 and 80 cm −1 . Steady-state deposition rates and corresponding compositions of the gas phase as a function of residence were determined. The deposition rates in mol/h increase with increasing [ A S / V R ] ratio at all investigated residence times up to 1 s. However, surface-related deposition rates in mol/m 2 h decreased. As the same results have been obtained in a preceding study using pure methane at a partial pressure of 10 kPa, it has been confirmed that all the kinetics can be determined by changing the [ A S / V R ] ratio.
