NOx Trap Catalysts and Technologies: Fundamentals and Industrial Applications
Chapter 10: Global Kinetic Modelling of the NSR Catalysts
Published:13 Jun 2018
Special Collection: 2018 ebook collection , ECCC Environmental eBooks 1968-2022Series: Catalysis Series
P. Kočí, in NOx Trap Catalysts and Technologies: Fundamentals and Industrial Applications, ed. L. Lietti and L. Castoldi, The Royal Society of Chemistry, 2018, ch. 10, pp. 279-320.
Download citation file:
This chapter focuses on a global kinetic model of NOx storage and reduction catalyst that serves as an effective software tool for design and optimization of exhaust gas aftertreatment systems in the automotive industry. Only key adsorbed components are considered and individual reaction steps on the surface are lumped into global reactions to minimize the system complexity. The aim is to predict the catalyst performance in a wide range of temperatures, flow rates and component concentrations in real exhaust mixture under highly dynamic operating conditions, enabling the optimization of monolith configuration and location in the exhaust treatment line, lean and rich phase timing, rich mixture composition, and LNT interaction with the other catalysts in the exhaust aftertreatment system (such as DOC and SCR). First, suitable transport models for monolith channel, catalytic washcoat and surface particle scale are introduced. The formulation of global rate laws is then discussed for main reactions that take place on the Pt(Pd)Rh/BaO/CeO2/Al2O3 catalyst type under varying air–fuel ratio: CO, H2 and hydrocarbon oxidation, water–gas shift and steam reforming, steady NO reduction, NO oxidation, NO2 reduction, oxygen storage effects, NOx adsorption, and reduction of the stored NOx that includes temporally and spatially distributed formation of by-products (N2, NH3 and NxO) during the catalyst regeneration.