A numerical study of emission control strategies in an iron powder burner

Abstract

We present a numerical investigation of emissions of NOx and nanoparticles within an iron powder burner. A steady 1D formulation of a burner is used to investigate emissions from a pre-heated burner, a burner equipped with external exhaust gas recirculation (EGR), and a burner equipped with staged combustion. We argue that a non-uniform particle concentration in the radial direction, a condition likely encountered in real-world scenarios, may result in localized particle combustion occurring under fuel-rich conditions, despite the fuel-lean inlet conditions. This, in turn, has a notable impact on emissions, as the trends are shown to be highly sensitive to the amount of non-uniformity obtained in a combustion chamber. Regarding emissions, burning iron powder in fuel-rich conditions with EGR shows promise in terms of stabilizing combustion, and reducing both NOx and nano-particle formation; however, complete conversion is not achieved. To mitigate emissions further, and to obtain complete fuel conversion, EGR in combination with staged combustion proves to be effective. Such an approach holds promise for achieving improved emission control and combustion efficiency.