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Singh S, Bhatia D. Diffusion–reaction phenomenon for negative-order reactions in flow reactors. Chem Eng Res Des 2019. [DOI: 10.1016/j.cherd.2019.05.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Paranjpe R, Suresh AK, Aghalayam P. Understanding Pt–Rh Synergy in a Three-Way Catalytic Converter. INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING 2013. [DOI: 10.1515/ijcre-2013-0072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
NO reduction to N2 is the key reaction for efficient operation of a three-way catalytic converter (TWC). It is reported that metal catalysts Pt and Rh co-exist as individual metals in a TWC to give synergistic performance. In this article, we have studied the NO + CO reaction for a 1:1 physical mixture of silica supported Pt and Rh catalysts using fixed bed experiments and microkinetic modeling. The microkinetic model [14] for the reaction on single metals Pt and Rh is simulated for the mixture case in CHEMKIN PRO®. It is observed that the mixture maintains the activity while producing less N2O (by-product of NO + CO reaction) thus enhancing N2 selectivity inspite of having only half amount of Rh. Analysis of surface coverages on individual metals in mixture shows that in the presence of Pt, CO poisoning of Rh is reduced at lower temperature leading to better overall conversion and selectivity. This has potential benefit in automotive catalysis, as it results in the formation of significantly lower amounts of N2O, an undesirable side-product and greenhouse gas; at a lower cost than if pure Pt/Rh catalysts were used.
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Marek M, Schejbal M, Kocí P, Nevoral V, Kubícek M, Hadac O, Schreiber I. Oscillations, period doublings, and chaos in CO oxidation and catalytic mufflers. CHAOS (WOODBURY, N.Y.) 2006; 16:037107. [PMID: 17014241 DOI: 10.1063/1.2354429] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Early experimental observations of chaotic behavior arising via the period-doubling route for the CO catalytic oxidation both on Pt(110) and Ptgamma-Al(2)O(3) porous catalyst were reported more than 15 years ago. Recently, a detailed kinetic reaction scheme including over 20 reaction steps was proposed for the catalytic CO oxidation, NO(x) reduction, and hydrocarbon oxidation taking place in a three-way catalyst (TWC) converter, the most common reactor for detoxification of automobile exhaust gases. This reactor is typically operated with periodic variation of inlet oxygen concentration. For an unforced lumped model, we report results of the stoichiometric network analysis of a CO reaction subnetwork determining feedback loops, which cause the oscillations within certain regions of parameters in bifurcation diagrams constructed by numerical continuation techniques. For a forced system, numerical simulations of the CO oxidation reveal the existence of a period-doubling route to chaos. The dependence of the rotation number on the amplitude and period of forcing shows a typical bifurcation structure of Arnold tongues ordered according to Farey sequences, and positive Lyapunov exponents for sufficiently large forcing amplitudes indicate the presence of chaotic dynamics. Multiple periodic and aperiodic time courses of outlet concentrations were also found in simulations using the lumped model with the full TWC kinetics. Numerical solutions of the distributed model in two geometric coordinates with the CO oxidation subnetwork consisting of several tens of nonlinear partial differential equations show oscillations of the outlet reactor concentrations and, in the presence of forcing, multiple periodic and aperiodic oscillations. Spatiotemporal concentration patterns illustrate the complexity of processes within the reactor.
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Affiliation(s)
- Milos Marek
- Department of Chemical Engineering and Center for Nonlinear Dynamics of Chemical and Biological Systems, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic.
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Kočí P, Štěpánek F, Kubíček M, Marek M. Meso-scale modelling of CO oxidation in digitally reconstructed porous Pt/γ-Al2O3 catalyst. Chem Eng Sci 2006. [DOI: 10.1016/j.ces.2005.12.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Brinkmeier C, Eigenberger G, Bernnat J, Tuttlies U, Schmeißer V, Opferkuch F. Autoabgasreinigung - eine Herausforderung für die Verfahrenstechnik. CHEM-ING-TECH 2005. [DOI: 10.1002/cite.200500111] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kryl D, Kočí P, Kubíček M, Marek M, Maunula T, Härkönen M. Catalytic Converters for Automobile Diesel Engines with Adsorption of Hydrocarbons on Zeolites. Ind Eng Chem Res 2005. [DOI: 10.1021/ie050249v] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David Kryl
- Department of Chemical Engineering and Department of Mathematics, Center for Nonlinear Dynamics of Chemical and Biological Systems, Prague Institute of Chemical Technology, Technická 5, CZ-16628 Praha 6, Czech Republic, and Ecocat R&D, Typpitie 1, FIN-90650 Oulu, Finland
| | - Petr Kočí
- Department of Chemical Engineering and Department of Mathematics, Center for Nonlinear Dynamics of Chemical and Biological Systems, Prague Institute of Chemical Technology, Technická 5, CZ-16628 Praha 6, Czech Republic, and Ecocat R&D, Typpitie 1, FIN-90650 Oulu, Finland
| | - Milan Kubíček
- Department of Chemical Engineering and Department of Mathematics, Center for Nonlinear Dynamics of Chemical and Biological Systems, Prague Institute of Chemical Technology, Technická 5, CZ-16628 Praha 6, Czech Republic, and Ecocat R&D, Typpitie 1, FIN-90650 Oulu, Finland
| | - Miloš Marek
- Department of Chemical Engineering and Department of Mathematics, Center for Nonlinear Dynamics of Chemical and Biological Systems, Prague Institute of Chemical Technology, Technická 5, CZ-16628 Praha 6, Czech Republic, and Ecocat R&D, Typpitie 1, FIN-90650 Oulu, Finland
| | - Teuvo Maunula
- Department of Chemical Engineering and Department of Mathematics, Center for Nonlinear Dynamics of Chemical and Biological Systems, Prague Institute of Chemical Technology, Technická 5, CZ-16628 Praha 6, Czech Republic, and Ecocat R&D, Typpitie 1, FIN-90650 Oulu, Finland
| | - Matti Härkönen
- Department of Chemical Engineering and Department of Mathematics, Center for Nonlinear Dynamics of Chemical and Biological Systems, Prague Institute of Chemical Technology, Technická 5, CZ-16628 Praha 6, Czech Republic, and Ecocat R&D, Typpitie 1, FIN-90650 Oulu, Finland
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Modeling of Transport and Transformation Processes in Porous and Multiphase Bodies. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s0065-2377(05)30003-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Kočí P, Kubíček M, Marek M. Periodic forcing of three-way catalyst with diffusion in the washcoat. Catal Today 2004. [DOI: 10.1016/j.cattod.2004.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Nonlinear dynamics of automobile exhaust gas converters: the role of nonstationary kinetics. Chem Eng Sci 2004. [DOI: 10.1016/j.ces.2004.07.115] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Kočí P, Kubíček M, Marek M. Modeling of Three-Way-Catalyst Monolith Converters with Microkinetics and Diffusion in the Washcoat. Ind Eng Chem Res 2004. [DOI: 10.1021/ie034137k] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Petr Kočí
- Departments of Chemical Engineering and of Mathematics, Center for Nonlinear Dynamics of Chemical and Biological Systems, Prague Institute of Chemical Technology, Technická 5, CZ-166 28 Prague, Czech Republic
| | - Milan Kubíček
- Departments of Chemical Engineering and of Mathematics, Center for Nonlinear Dynamics of Chemical and Biological Systems, Prague Institute of Chemical Technology, Technická 5, CZ-166 28 Prague, Czech Republic
| | - Miloš Marek
- Departments of Chemical Engineering and of Mathematics, Center for Nonlinear Dynamics of Chemical and Biological Systems, Prague Institute of Chemical Technology, Technická 5, CZ-166 28 Prague, Czech Republic
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