Efficient low temperature lean NOx reduction over Ag/Al2O3-A system approach
2011 (English)In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 104, no 1-2, 74-83 p.Article in journal (Refereed) Published
This study focuses on lean NOx reduction (LNR) by n-octane using silver-alumina based catalysts, with the addition of hydrogen. The work takes a system approach, where parameters such as temperature, reformate gas composition, fuel penalty and realistic monolith samples are considered. The LNR catalyst samples were prepared by impregnation and sol-gel methods and the NOx reduction performance was characterized by flow-reactor experiments, where realistic engine-out gas compositions were used. The hydrogen feed over the LNR catalyst samples was determined via data achieved by autothermal reforming experiments over a rhodium based catalyst, using real diesel as feedstock. The LNR catalyst samples generally show an enhanced NOx reduction when hydrogen is added to the gas feed. In particular, a 2 wt% silver-alumina sample with the addition of minute amounts of platinum, shows a high increase in NOx reduction when hydrogen is added to the feed. The addition of CO, a potential poison in the reaction and a by-product from the reforming, did not show any significant effect on the LNR catalyst performance at the conditions used. This is beneficial, since it renders a CO clean-up step in the reformer system unneeded. Ammonia formation is discussed in terms of a possible dual-SCR system. Finally, the fuel penalty for hydrogen production and hydrocarbon addition is taken into consideration. It is found that an addition of 1000 ppm H-2 leads to unacceptable fuel penalties.
Place, publisher, year, edition, pages
2011. Vol. 104, no 1-2, 74-83 p.
Lean NOx reduction, Ag/Al2O3, Pt, Fuel reforming, Fuel economy
Physical Chemistry Other Environmental Engineering Chemical Engineering
IdentifiersURN: urn:nbn:se:kth:diva-34396DOI: 10.1016/j.apcatb.2011.02.026ISI: 000290704500010ScopusID: 2-s2.0-79954414543OAI: oai:DiVA.org:kth-34396DiVA: diva2:420952
FunderKnut and Alice Wallenberg Foundation, KAW 2005.0055
QC 201106072011-06-072011-06-072011-06-07Bibliographically approved