Transient Kinetic Modeling of the Ethylene and Carbon Monoxide Oxidation over a Commercial Automotive Exhaust Gas Catalyst

• Published in: Industrial & engineering chemistry research Vol. 39; no. 3; pp. 599 - 609
• Main Authors: Harmsen, Jan M. A, Hoebink, Jozef H. B. J, Schouten, Jaap C
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.03.2000
• Subjects: ADVANCED PROPULSION SYSTEMS; Air pollution caused by fuel industries; AIR POLLUTION CONTROL; ALUMINIUM OXIDES; Applied sciences; Atmospheric pollution; CARBON MONOXIDE; Catalysis; CATALYTIC CONVERTERS; CATALYTIC EFFECTS; Catalytic reactions; CERIUM OXIDES; CHEMICAL REACTION KINETICS; Chemistry; Energy; Energy. Thermal use of fuels; ENVIRONMENTAL SCIENCES; ETHYLENE; Exact sciences and technology; EXHAUST GASES; General and physical chemistry; KINETIC EQUATIONS; OXIDATION; PLATINUM; Pollution; Pollution reduction; Prevention and purification methods; RHODIUM; Stack gas and industrial effluent processing; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Transports and other; Cerium Oxides; Motor car; Catalytic reaction; Ruthenium; Hydrocarbon; Ethylene; Transition metal; Motor vehicle; Experimental study; Supported catalyst; Heterogeneous catalysis; Gamma form; Kinetic model; Catalytic converter; Platinum; Three way catalyst; Physicochemical purification; Exhaust gas; Oxidation; Carbon monoxide; Platinoid; Alumina; Flue gas purification
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie990614g

The transient kinetics of ethylene oxidation by oxygen over a commercial Pt/Rh/CeO2/γ-Al2O3 three-way catalyst were modeled. Experiments were carried out in a fixed-bed microreactor with two separate inlets, enabling alternate feeding of ethylene and oxygen with frequencies up to 1/4 Hz. The experimental conditions resemble the cold-start period of an Otto engine in a car. Two types of adsorbed ethylene species seem to exist. A selective catalyst deactivation for oxygen adsorption, due to deposition of carbonaceous species, was found. A kinetic model was developed, based on elementary reaction steps, that allows one to describe the experiments quantitatively. Furthermore, this model was combined with the published model for transient carbon monoxide oxidation over the same catalyst, which enables one to predict the results of simultaneous ethylene and carbon monoxide oxidation. Both components react in rather distinct zones, with ethylene being converted only when carbon monoxide oxidation is almost complete.