Deactivation mechanisms influencing the performance and durability of exhaust aftertreatment systems
The vehicular transport sector has the highest share of nitrogen oxides (NOx) emissions, mostly addressed for diesel vehicles. Lean NOx trap (LNT) represents a simple and cost-efficient solution for the abatement of NOx emissions from lean-burn diesel engines. Although LNTs have been commercialized for some applications, the durability of LNT catalysts still remains problematic; sulfur poisoning and thermal aging are the major causes of deactivation. Part of this thesis explored the deactivation mechanisms affecting the performance and durability of commercial LNTs through engine bench, vehicle chassis dynamometer and flow reactor experiments. Likewise, this work intended to establish a proper correlation between vehicle-aged and rapid-aged LNT catalysts, which is critical for cost effectiveness when evaluating new catalyst formulations. Particular attention was also given to the role of modern LNT materials on the sulfur poisoning and regeneration characteristics due to the relevance of this deactivation mechanism on the LNT performance and durability.
Furthermore, gasoline vehicles equipped with direct injected gasoline (GDI) engines can produce important amounts of particulate matter. Therefore, many automotive manufacturers are now equipping gasoline powered vehicles with a gasoline particle filter (GPF) in their exhaust system to have a reliable PM and PN reduction and comply with current and future emission limits. Probably the most economical way to introduce this technology into a gasoline exhaust system, that already contains one or more TWCs, is to combine TWC + GPF in one single device, referred to as coated gasoline particulate filter (cGPF). In this thesis, the conversion efficiency and durability of model cGPF catalysts were also studied under different feed temperatures and multicomponent feed gas mixtures. The samples consisted of soot-free and real soot-loaded GPFs coated with TWC material. The experimental results were then used to develop a global kinetic model able to capture the CO, ethylene and toluene conversion behavior both in soot-free and soot-loaded cGPFs.
Gasoline particulate filters
Lean NOx traps
Jesus De Abreu Goes
Chalmers, Kemi och kemiteknik, Kemiteknik, Kemisk apparatteknik
Performance Studies and Correlation between Vehicle- and Rapid- Aged Commercial Lean NOx Trap Catalysts
SAE International Journal of Engines,; Vol. 10(2017)p. 1613-1626
Paper i proceeding
Detailed Characterization Studies of Vehicle and Rapid Aged Commercial Lean NOx Trap Catalysts
Industrial & Engineering Chemistry Research,; Vol. 57(2018)p. 9362-9373
Artikel i vetenskaplig tidskrift
Sulfur Poisoning Effects on Modern Lean NOx Trap Catalysts Components
Catalysts,; Vol. 9(2019)
Artikel i vetenskaplig tidskrift
Manuscript - Jesus De Abreu Goes, Jung Won Woo and Louise Olsson, Effects of Feed Gas Composition on Fresh and Aged TWC Coated-GPFs Loaded with Real Soot
Manuscript - Jesus De Abreu Goes, Louise Olsson and Timothy C. Watling, Global Kinetic Model of a TWC-Coated GPF: Catalytic Effects of Soot Accumulation
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4774
Chalmers tekniska högskola
KB-salen, Kemigården 4, Chalmers.
Opponent: Dr. Robert E. Hayes