Numerical Simulation of Ammonia Concentration Distribution in SCR Catalytic Filter Device for Diesel NO<SUB>x</SUB> Aftertreatment System

다국어 초록 (Multilingual Abstract)

Selective catalytic reduction (SCR) is a successful technique to reduce NO<SUB>x</SUB> emissions in diesel exhaust gases. The aim of current study is to develop a SCR catalytic filter device for reducing NO<SUB>x</SUB> and soot emissions simultaneously in diesel combustors. SCR catalysts are used to reduce NO<SUB>x</SUB> emissions, and the novel catalytic filters inside SCR system are especially designed and manufactured to reduce soot particles. NH₃ or urea (which is converted to ammonia) is injected into exhaust stream then reacts with NO<SUB>x</SUB> emissions over the catalyst surface of SCR device, so that a uniform distribution of NH₃ is one of the challenges in the novel design of SCR device in order to attain NO<SUB>x</SUB> conversion and reduce NH₃ slip optimally. In this study, three catalytic filters with 120° interval are vertically mounted under the horizontal plate. Ammonia is injected radially perpendicular into the inlet main flow. The ammonia concentration in the SCR catalytic filter device is investigated by numerical simulation. Gaseous flow in SCR catalytic filter device is modeled as laminar and turbulent flow by varying the Reynolds numbers. The results show that there is the small influence of circulations on the ammonia concentration near the inlet domain at the low Reynolds number. On the contrary, the high influence of circulations on the ammonia concentration is observed at high Reynolds number.