Objectives

1. Oxidation of NO 0.2 L 6 L 950 ppm NO 50 ppm NO2 600 ppm NO 400 ppm NO2 250 ppm NO 250 ppm NO2 6 L 24 L 950 ppm NO 50 ppm NO2 250 ppm NO 250 ppm NO2 6 L Modeling and simulation of a two unit catalytic converter:Ru/NaY NOx adsorbent combined with an oxidation catalystR. Zukermana, L. Vradmanb, M. Herskowitza E. Livertsa, E. Godardc, J. A. Martensc, J. F. Brilhacd, P. G. Blakemane, L. PeaceeaBlechner Center for Industrial Catalysis and Process Development, Department of Chemical Engineering, Ben-Gurion University of the Negev, IsraelbDepartment of Chemical Engineering, Sami Shamoon College of Engineering, IsraelcCentrum voor Oppervlaktechemie en Katalyse, Katholieke Universiteit Leuven, BelgiumdLaboratoire Gestion des Risques et Environnement, Universite´ de Haute-Alsace, FranceeJohnson Matthey Environmental Catalysts and Technologies, European Technology Centre, UK Introduction One of the critical stages in development of this converter is construction of the model that simulates the system. Published models of aftertreatment technologies simulate only 1-unit catalytic converters. In this work, the performances of catalytic converter containing oxidation catalyst and Ru/Na-Y NOx trap were simulated by an integral simulation model based on FEMLAB package Objectives • Develop Kinetic model for Oxidation catalyst • Modeling and Simulation of an integrated system in transient conditions at lean and rich mode • Synchronization and optimization the two unit catalytic converter operation Kinetic model for oxidation catalyst • Lean exhaust gas: • Composition - 200-1100 ppm NOx, 50 ppm CO, 30 ppm C3H6 • Conditions - 150-475oC, GHSV of 130,000h-1 – 1,300,000h-1 • Simplified assumptions were embedded • Only three reactions were considered • Isothermal conditions • Mass transfer effect was neglected • ACSL package was used for parameter estimation • FEMLAB 3.1 program was used for simulations • E-R Model • Oxidation of CO • L-H Model • Oxidation of C3H6 • Power law Model “1-Dimensional single Channel” model Ru/Na-Y catalyst displays significant desorption at rich mode Model Assumptions: 1. Adiabatic, plug flow operation 2. Negligible diffusion limitation in the solid phase 3. Negligible heat radiation 4. No homogenous reactions in the gas phase Ru/Na-Y co-adsorbs NO and NO2 T=250oC Mass balance -Gas phase: Solid phase: Energy balance -Gas phase: Solid phase: Active site balance - NO is the main NOx component in the exhaust gas Oxidation activity of Ru/NaY is relatively low T=250oC Addition of Oxidation unit reduces the system volume significantly Conclusions • A platform capable to simulate the dynamic behavior of several connected units was developed • The balance between adsorbed and desorbed amount of NOx is achieved on Ru/Na-Y catalyst • NO oxidation rate on Ru/Na-Y limits the NOx adsorption. Addition of oxidation unit reduces the 2-fold system volume T=250oC, Volumetric flowrate = 80m3/h Oxidation unit JM-Oxicat NOx Storage unit Ru/Na-Y Acknowledgment NOx Storage unit Ru/Na-Y This work was performed in the AHEDAT project, sponsored by the European Commission in the Fifth Framework Programme