A Modeling Study of Soot and De-NOx Reaction Phenomena in SCRF Systems 2011-37-0031

The development of thermally durable zeolite NH₃/Urea-SCR formulations coupled with that of high porosity filters substrates has opened the way to integrate PM and NOx control into a single device, namely an SCR-coated Diesel Particulate Filter (SCRF). A few experimental works are already present in the literature regarding SCRF systems, mainly addressing the DeNOx performances of the system (in both presence and absence of soot) under both steady state and transient conditions. The purpose of the present work is to perform a simulation study focused on phenomena which are expected to play key roles in SCRF systems, such as coupling of reaction and diffusion phenomena, soot effect on DeNOx activity, SCR coating effect on soot regeneration and filtration efficiency and competition between soot oxidation and DeNOx processes involving NO₂. Subsequently, a concept analysis was carried out to comparatively study a DOC+SCRF system and a DOC+DPF+SCR one with respect to the continuously regeneration (CRT®) operation.