Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Book Description
The original goal of this program was the identification and design of new noble-metal-based catalysts for the selective catalytic reduction of nitric oxide by hydrocarbons under excess oxygen (i.e., ''lean'') conditions (HC-SCR). Work conducted in the first funding cycle of this award (i.e., 1997-2000) was successful in allowing us to develop an understanding of the fundamental surface chemistry taking place during the adsorption and reaction of nitrogen oxides and propylene on the surface of supported noble metal catalysts. Both experimental results collected in our own group as well as molecular simulation results published by Professor Neurock suggested that in order to improve the performance of the Pt catalysts--in terms of the nitrogen selectivity and the temperature window of operation-- it was necessary to introduce a second metal. However, synthesizing such catalysts with the metals of interest (i.e., Pt-Au, Pt-Ru, Pt-Rh, etc.) with some degree of control of the structure and composition of the resulting supported metal particles is in itself a research challenge. Consequently, the bulk of our efforts during the second funding cycle of this award (covered by this report) was shifted to the use of organometallic cluster precursors for the synthesis on novel bimetallic catalysts. During this time we have also continued to maintain an interest in NOx abatement, but have redirected our efforts from the HC-SCR process to the more promising from a commercial standpoint NOx Storage Reduction (NSR) approach.
New Heterogeneous Catalysts for the Selective Reduction of NOx Under Lean Conditions. Final Report
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Book Description
The original goal of this program was the identification and design of new noble-metal-based catalysts for the selective catalytic reduction of nitric oxide by hydrocarbons under excess oxygen (i.e., ''lean'') conditions (HC-SCR). Work conducted in the first funding cycle of this award (i.e., 1997-2000) was successful in allowing us to develop an understanding of the fundamental surface chemistry taking place during the adsorption and reaction of nitrogen oxides and propylene on the surface of supported noble metal catalysts. Both experimental results collected in our own group as well as molecular simulation results published by Professor Neurock suggested that in order to improve the performance of the Pt catalysts--in terms of the nitrogen selectivity and the temperature window of operation-- it was necessary to introduce a second metal. However, synthesizing such catalysts with the metals of interest (i.e., Pt-Au, Pt-Ru, Pt-Rh, etc.) with some degree of control of the structure and composition of the resulting supported metal particles is in itself a research challenge. Consequently, the bulk of our efforts during the second funding cycle of this award (covered by this report) was shifted to the use of organometallic cluster precursors for the synthesis on novel bimetallic catalysts. During this time we have also continued to maintain an interest in NOx abatement, but have redirected our efforts from the HC-SCR process to the more promising from a commercial standpoint NOx Storage Reduction (NSR) approach.
Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Book Description
The original goal of this program was the identification and design of new noble-metal-based catalysts for the selective catalytic reduction of nitric oxide by hydrocarbons under excess oxygen (i.e., ''lean'') conditions (HC-SCR). Work conducted in the first funding cycle of this award (i.e., 1997-2000) was successful in allowing us to develop an understanding of the fundamental surface chemistry taking place during the adsorption and reaction of nitrogen oxides and propylene on the surface of supported noble metal catalysts. Both experimental results collected in our own group as well as molecular simulation results published by Professor Neurock suggested that in order to improve the performance of the Pt catalysts--in terms of the nitrogen selectivity and the temperature window of operation-- it was necessary to introduce a second metal. However, synthesizing such catalysts with the metals of interest (i.e., Pt-Au, Pt-Ru, Pt-Rh, etc.) with some degree of control of the structure and composition of the resulting supported metal particles is in itself a research challenge. Consequently, the bulk of our efforts during the second funding cycle of this award (covered by this report) was shifted to the use of organometallic cluster precursors for the synthesis on novel bimetallic catalysts. During this time we have also continued to maintain an interest in NOx abatement, but have redirected our efforts from the HC-SCR process to the more promising from a commercial standpoint NOx Storage Reduction (NSR) approach.
Catalytic Reduction of NOx Under Lean Conditions
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 81
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 81
Book Description
Heterogeneous Catalysts for Clean Technology
Author: Karen Wilson
Publisher: John Wiley & Sons
ISBN: 3527659005
Category : Science
Languages : en
Pages : 466
Book Description
Reactive, but not a reactant. Heterogeneous catalysts play an unseen role in many of today's processes and products. With the increasing emphasis on sustainability in both products and processes, this handbook is the first to combine the hot topics of heterogeneous catalysis and clean technology. It focuses on the development of heterogeneous catalysts for use in clean chemical synthesis, dealing with how modern spectroscopic techniques can aid the design of catalysts for use in liquid phase reactions, their application in industrially important chemistries - including selective oxidation, hydrogenation, solid acid- and base-catalyzed processes - as well as the role of process intensification and use of renewable resources in improving the sustainability of chemical processes. With its emphasis on applications, this book is of high interest to those working in the industry.
Publisher: John Wiley & Sons
ISBN: 3527659005
Category : Science
Languages : en
Pages : 466
Book Description
Reactive, but not a reactant. Heterogeneous catalysts play an unseen role in many of today's processes and products. With the increasing emphasis on sustainability in both products and processes, this handbook is the first to combine the hot topics of heterogeneous catalysis and clean technology. It focuses on the development of heterogeneous catalysts for use in clean chemical synthesis, dealing with how modern spectroscopic techniques can aid the design of catalysts for use in liquid phase reactions, their application in industrially important chemistries - including selective oxidation, hydrogenation, solid acid- and base-catalyzed processes - as well as the role of process intensification and use of renewable resources in improving the sustainability of chemical processes. With its emphasis on applications, this book is of high interest to those working in the industry.
The Selective Catalytic Reduction of NOx by CH?b3?sOH Under Oxidising Conditions Over Al?b2?sO?b3?s Based Catalysts
Author: Eibhlin Halpin
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Studies of Platinum Dispersion and Catalyst Architecture for Lean NOx Reduction
Author: Bijesh Man Shakya
Publisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages :
Book Description
The combination of NOx storage and reduction (NSR) and selective catalytic reduction (SCR) catalyst is a promising technology for the reduction of NOx emission from the exhaust of lean-burn or diesel engine vehicles. In the combined NSR/SCR system, NH3 generated in LNT during the rich phase is utilized in the SCR for additional NOx conversion. Therefore, the performance of the combined NSR/SCR depends strongly on the NH3 generating function of the NSR catalyst. Earlier studies show that lower Pt dispersion NSR catalysts give higher selectivity to NH3 making them ideal candidates for this particular application. In the first part of the work, we performed experiments on lower Pt dispersion catalysts to gain insights on the mechanistic effects of Pt dispersion on NOx conversion and selectivity. We also developed an improved crystallite-scale model of NSR that explicitly accounts for the crystallite scale gradients of the stored NOx. The calibrated model is able to capture the effects of Pt dispersion, rich phase duration and overall cycle time on cycle-averaged conversion and selectivity trends. In the second part, we carried out a simulation study of dual-layer NSR+SCR monolithic catalyst using (1+1)-D model of catalytic monolith with individually-calibrated global kinetic models. Simulations show that multiple combinations of catalyst loading can attain a given NOx conversion and N2 selectivity, and that there exists a loading of SCR washcoat for a given NSR catalyst for which the NOx conversion is maximum. Simulations of the dual-brick monolith are also performed to analyze the effects of catalyst architecture. Under identical conditions, the simulations show that dual-layer catalyst outperforms the dual-brick largely because of the better utilization of generated NH3. Finally, we performed an optimization study to identify optimal loading and configuration of combined Fe+Cu zeolite catalyst that gives overall high NOx removal efficiency over a broad range of temperature. Simulations suggest that the brick configuration in which Fe- brick is followed by Cu- catalyst is slightly better than dual-layer in which Fe- is coated on top of Cu- architecture. This is attributed to the diffusional limitations in the washcoat that is more pronounced in the dual-layer catalysts.
Publisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages :
Book Description
The combination of NOx storage and reduction (NSR) and selective catalytic reduction (SCR) catalyst is a promising technology for the reduction of NOx emission from the exhaust of lean-burn or diesel engine vehicles. In the combined NSR/SCR system, NH3 generated in LNT during the rich phase is utilized in the SCR for additional NOx conversion. Therefore, the performance of the combined NSR/SCR depends strongly on the NH3 generating function of the NSR catalyst. Earlier studies show that lower Pt dispersion NSR catalysts give higher selectivity to NH3 making them ideal candidates for this particular application. In the first part of the work, we performed experiments on lower Pt dispersion catalysts to gain insights on the mechanistic effects of Pt dispersion on NOx conversion and selectivity. We also developed an improved crystallite-scale model of NSR that explicitly accounts for the crystallite scale gradients of the stored NOx. The calibrated model is able to capture the effects of Pt dispersion, rich phase duration and overall cycle time on cycle-averaged conversion and selectivity trends. In the second part, we carried out a simulation study of dual-layer NSR+SCR monolithic catalyst using (1+1)-D model of catalytic monolith with individually-calibrated global kinetic models. Simulations show that multiple combinations of catalyst loading can attain a given NOx conversion and N2 selectivity, and that there exists a loading of SCR washcoat for a given NSR catalyst for which the NOx conversion is maximum. Simulations of the dual-brick monolith are also performed to analyze the effects of catalyst architecture. Under identical conditions, the simulations show that dual-layer catalyst outperforms the dual-brick largely because of the better utilization of generated NH3. Finally, we performed an optimization study to identify optimal loading and configuration of combined Fe+Cu zeolite catalyst that gives overall high NOx removal efficiency over a broad range of temperature. Simulations suggest that the brick configuration in which Fe- brick is followed by Cu- catalyst is slightly better than dual-layer in which Fe- is coated on top of Cu- architecture. This is attributed to the diffusional limitations in the washcoat that is more pronounced in the dual-layer catalysts.
Selective Catalytic Reduction of NOx
Author: Oliver Kröcher
Publisher: MDPI
ISBN: 3038973645
Category : Science
Languages : en
Pages : 281
Book Description
This book is a printed edition of the Special Issue "Selective Catalytic Reduction of NOx" that was published in Catalysts
Publisher: MDPI
ISBN: 3038973645
Category : Science
Languages : en
Pages : 281
Book Description
This book is a printed edition of the Special Issue "Selective Catalytic Reduction of NOx" that was published in Catalysts
New Concepts in Selective Oxidation Over Heterogeneous Catalysts
Author: Gabriele Centi
Publisher:
ISBN:
Category :
Languages : en
Pages : 192
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 192
Book Description
Multiphase Catalysts for Selective Reduction of NOx with Hydrocarbons
Author: Sergio Eduardo Maisuls
Publisher:
ISBN: 9789036514293
Category :
Languages : en
Pages : 132
Book Description
Publisher:
ISBN: 9789036514293
Category :
Languages : en
Pages : 132
Book Description
Selective Catalytic Reduction for Treating the NOx Emissions from Lean-Burn Gasoline Engines
Author: Joseph R. Theis
Publisher:
ISBN:
Category :
Languages : en
Pages : 12
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 12
Book Description
มหและจุลกายวิภาคศาสตร์เชิงระบบต่อมไร้ท่อ
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description