Deactivation mechanisms influencing the performance and durability of exhaust aftertreatment systems
Doktorsavhandling, 2020

As countermeasure to air pollution and global warming, more stringent environmental policy measures will probably come into force with the future emission standards, which will require important developments for gasoline and diesel vehicles to meet the emerging criteria. Efficient catalytic formulations and advanced strategies for exhaust aftertreatment systems will be therefore demanded to provide both high catalytic activity and stability, minimizing the environmental impact by automobiles.

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.

Sulfur poisoning.

Thermal degradation

Gasoline particulate filters

Lean NOx traps

KB-salen, Kemigården 4, Chalmers.
Opponent: Dr. Robert E. Hayes

Författare

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

Catalysts are widely applied for the control and reduction of the exhaust emissions from gasoline- and diesel-powered vehicles by converting harmful pollutants to their corresponding harmless products. These series of catalysts are generally referred to as exhaust aftertreatment systems (EATS). As emissions regulations become more stringent and continue to drive towards cleaner vehicles, it is required that EATS exhibit excellent catalytic activity and durability. Therefore, developing new catalysts based on accurate understanding of the mechanisms affecting the catalyst durability is critical. Thereby, the aim of this thesis work was to explore the mechanisms affecting the catalytic activity of key components commonly found in diesel and gasoline EATS, with the purpose of providing useful information to optimize the catalyst management for better performance and durability.

Drivkrafter

Hållbar utveckling

Styrkeområden

Transport

Ämneskategorier

Kemiteknik

ISBN

978-91-7905-307-9

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4774

Utgivare

Chalmers tekniska högskola

KB-salen, Kemigården 4, Chalmers.

Online

Opponent: Dr. Robert E. Hayes

Mer information

Senast uppdaterat

2020-05-18