Search results for "Catalytic converter"
showing 4 items of 4 documents
Voltammetric Analysis of Platinum in Environmental Matrices
2014
This article will summarize measurement data for Pt in different environmental samples obtained by the authors using a recently developed approach by voltammetric analysis. A fast accumulation of platinum and rhodium in the environmental and biological matrices has been observed in the last few years and concern has arisen about potential environmental and health risks. Voltammetry was used for the determination of Pt and Rh in airborne particulate collected in Palermo, Italy. Possible interferences by other environmental metals have also been evaluated. All samples show concentrations of Pt and Rh above average upper crust values. The Pt and Rh concentrations in particulate samples collect…
Development of a combined solver to model transport and chemical reactions in catalytic wall-flow filters
2017
Abstract In this work, we develop a non-isothermal model for diesel particulate filters including exothermic and competing chemical reactions. We begin with an isothermal, single-reaction model and we gradually increase its complexity. By comparing various models, we aim at establishing the minimum degree of complexity required to effectively model the system under investigation. Based on the numerical simulations, we conclude that isothermal models are adequate only if the temperature of the catalyst is, at all times, completely below or completely above a critical temperature. However, if the goal is to predict the critical temperature, only non-isothermal models should be used. The resul…
From a fixed bed Ag–alumina catalyst to a modified reactor design: how to enhance the crucial heterogeneous–homogeneous reactions in HC-SCR
2004
Abstract A highly active Ag/alumina catalyst for continuous reduction of NO to nitrogen with n-octane under lean conditions was prepared. It was observed in the reactor set-up experiments for optimization of the converter, that surface generated gas phase species are crucial for obtaining high conversion. EPR and matrix isolated FTIR studies at low temperature (10–18 K) were performed for identification of the radicals. Experimental data, observed at steady state conditions in the temperature range 300–550 °C, was used to produce an artificial neural network model of the catalytic converter with four catalyst beds.
Stochastic modeling and prediction of catalytic converters degradation
2009
This paper proposes a stochastic model for describing the degradation process of catalytic converters over time, where the degradation is indirectly measured through the emission of complex hydrocarbons (HC) in legislated driving cycles. The proposed model is the superposition of two processes, the former being a dependent increments process which describes the actual degradation process, and the latter a white noise process which models the experimental errors. In particular, the proposed model assumes that the degradation growth in a small usage interval depends on the degradation level at the beginning of the interval, rather than on the age of the converter. The model has been applied t…