Impact of Catalyst Geometry on Diffusion and Selective Catalytic Reduction Kinetics under Elevated Pressures

Abstract

In marine diesel engine applications, selective catalytic reduction (SCR) upstream of the turbocharger may become the preferred technology when dealing with high sulfur fuels and low exhaust gas temperatures. The target nitrogen oxide reductions in combination with minimum ammonia slip and reduced gas diffusion rates under elevated pressures require understanding of the impact of catalyst geometry on the SCR kinetics. The extent, trends, and sources for this observation are elucidated in this work by systematic testing of catalysts with equal geometry and/or intrinsic activity.

Analysis of the Driving Altitude and Ambient Temperature Impact on the Conversion Efficiency of Oxidation Catalysts

“…In particular, the exhaust pressure dependence on the driving altitude is reflected in a relevant variation of the pollutants' partial pressure. The volumetric flow rate of the exhaust gas also suffers a direct variation and, consequently, the flow dwell time [27]. The dwell time increase improves the mass transfer of the pollutants toward the catalyst active sites, which implies higher conversion efficiency [28] and a reduction of the light-off temperature [29].…”