An Analysis of a Reacting Flow through a Selective Reduction Converter (SCR) to Reduce NOx Emission

In recent years, due to more stringent emission regulations, engine out exhaust gas emissions such as hydrocarbons, nitrogen oxides, carbon monoxide and suspended particles must be reduced. In order to comply with emission regulations, selective catalytic reduction (SCR) converter is one of the many ways to reduce the amount of emissions. When the exhaust gas passes through the converter, the nitrogen oxides are reduced to nitrogen and water. The purpose of this study is to study the gas flow through a catalytic SCR converter using computational fluid dynamics (CFD) software.



An SCR using bimetallic Fe-Cu-ZSM-5 catalyst is studied. The effects of major flow parameters such as compositions of the catalyst, temperature, the gaseous flow rate at the inlet and the thickness of the catalyst on performance of the SCR at low temperature is studied. The chemical kinetics models are taken from the literature to model the chemical reactions in the device. Now, the catalysts with different compositions are modelled as if they are different monometallic catalyst, each with a calibrated set of chemical kinetics parameters. Due to special filters in the converters we use, we assume that the chemical reactions in the simulation are volumetric reactions.