Efficient low temperature lean NOx reduction over Ag/Al2O3-A system approach
Journal article, 2011

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. (C) 2011 Elsevier B.V. All rights reserved.

selective catalytic-reduction

nitrogen-oxides

diesel

engine exhaust

Pt

silver-alumina catalysts

in-situ ftir

Ag/Al2O3

higher hydrocarbons

silver/alumina catalyst

Fuel reforming

Lean NOx reduction

Fuel economy

nitric-oxide

rhodium-oxide

Author

Hannes Kannisto

Competence Centre for Catalysis (KCK)

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

X. Karatzas

Royal Institute of Technology (KTH)

J. Edvardsson

Volvo Group

Lars Pettersson

Royal Institute of Technology (KTH)

Hanna Härelind Ingelsten

Competence Centre for Catalysis (KCK)

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

Applied Catalysis B: Environmental

0926-3373 (ISSN) 1873-3883 (eISSN)

Vol. 104 1-2 74-83

Driving Forces

Sustainable development

Areas of Advance

Nanoscience and Nanotechnology

Transport

Energy

Materials Science

Subject Categories

Chemical Sciences

DOI

10.1016/j.apcatb.2011.02.026

More information

Latest update

11/23/2018