A kinetic model for SCR coated particulate filters—Effect of ammonia-soot interactions

Understanding the multiple interactions in vanadium-based SCR catalysts during simultaneous NOx and soot abatement

“…According to previous literature, ammonia interacts with soot and the formation of amine/ amide intermediates blocks the soot surface and inhibits the oxidation reactions. 13 In a combined 2-way SCRonDPF system maintaining a high NO x reduction performance in long-term is dependent on a good soot oxidation activity, which prevents the growth of a diffusive barrier layer on the catalyst surface. 24 The reaction mechanism of soot oxidation is influenced by various parameters such as the catalyst composition, the soot-catalyst contact and the reaction atmosphere.…”

“…Cu-exchanged zeolites, due to their high NH 3 -SCR of NO x activity and thermal stability, have been evaluated for coating on filters by several research groups. 9–13 Decreased NH 3 storage and lower NO conversion were found for a soot-loaded DPF coated with a Cu-containing zeolite washcoat. 24 Furthermore, such catalysts are sensitive to sulfur poisoning, and therefore not optimal for applications where a high sulfur resistance is required.…”

“…In recent years, a novel concept of coating SCR catalysts on the highly porous wall of the DPF has been proposed and this leads to an integrated 2-way SCRonDPF system (also referred to as SCR/DPF, SDPF or SCRF). [7][8][9][10][11][12][13][14][15][16] The simultaneous NO x and soot removal can therefore be achieved in such multifunctional systems. [17][18][19][20][21][22][23] The more compact design can reduce the overall volume and costs significantly.…”

“…In this respect, NO 2 as a more reactive oxidant than O 2 was observed to considerably increase the soot conversion, [39][40][41] also by supporting the reoxidation of the catalyst active sites. 42,43 Based on the study of Trandafilović et al 13 ammonia was suggested to interact with the soot surface and form amines/ amides (-C-NH 2 ) that can inhibit further oxidation. Mehring et al 44 studied the SCR of NO x with ammonia over soot, and demonstrated its catalytic contribution to the fast SCR reaction by providing adsorption sites for ammonia and NO x species.…”

Most Recent Advances in Diesel Engine Catalytic Soot Abatement: Structured Catalysts and Alternative Approaches

“…The modeling of the integrated unit is very difficult, since the developed model must be able to successfully include the competition of soot oxidation and SCR reaction for available NO 2 , the interaction of washcoat loading on deNOx performance, PM filtration efficiency, and system pressure drop [95]. Trandafilović et al studied the effect of soot loading on a Cu/SSZ-13 zeolite in standard SCR, NH 3 oxidation, NH 3 TPD, and soot oxidation [96]. The SCR and NH 3 oxidation tests have shown that, in the presence of 10 g/L of soot, the activity of Cu/SSZ-13 was not influenced.…”