Numerical Simulation on Effect of Heating Temperature upon the Gaseous Flow in a SCR Catalytic Filter Device

摘要

Selective catalytic reduction (SCR) and diesel particulate filter (DPF) as a compact system are used to reduce NO_x and soot emissions, respectively. The aim of this study is to develop an SCR catalytic filter device for reducing simultaneously NO_x and soot emissions from a combustor. In order to attain the optimal NO_x conversion, the amount of ammonia must be managed to the amount of NO_x on catalyst surface. If the amount of ammonia is higher than that of NO_x, ammonia slip will be presented. Therefore, the uniform ammonia distribution around the catalyst is one of the challenges for the SCR application. Temperature is also a sensitive parameter in the reaction rate of NO_x with ammonia. In this paper, the heating effect on the gaseous flow in the SCR catalytic filter device is studied with the uniformity of ammonia distribution. As a result, it is found that the temperature around catalytic filters is lower at Re = 4255 than that at Re = 64. The result also shows that the mixing index decreases as increasing the heating temperature in SCR device.