A Laboratory Study of NOX Reduction During the Rich Operating Period Over a NOX Storage Catalyst Université de Haute Alsace

Format:

Conference/Event

Author/Creator:

Fendeleur, S., author.

Conference Name:

International Fuels and Lubricants Meeting and Exposition (1999-10-25 : Toronto, Canada)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 1999

Summary:

The behaviour of a NOx storage catalyst in powdered form and containing a storage component based on alkaline metal was investigated under rich conditions. Experiments were conducted in a fixed-bed flow reactor with the space velocity set at 45,000 h-1.From these experiments it was possible to extract the fractional NOx reduction and the efficiency of use of the reductant. With 0.9% CO as a reductant at 350°C, complete utilisation of CO was achieved up to 70% NOx conversion as treatment time was increased. To obtain 90% NOx conversion required longer times, and 23% of the CO did not participate in the reduction of NOX. A reductant balance shows that about 40% of the CO added is used to reduce the catalyst surface when the flow is switched from lean to rich.The ranking of efficiencies of different reductant gases at 350°C gave the following sequence: 0.9% H2 0.9% CO > 1285 ppm toluene > 3000 ppm propene 1125 ppm i-octane > 3000 ppm propane. Thus in an actual exhaust the NOx reduction is due mainly to H2 and CO. A study of the effect of temperature showed that maximum efficiency is obtained in the range 350 to 400°C. A study of the effect of concentration showed that for the injection of a given mass of reductant (CO), it is better to use a shorter burst at higher concentration. The competition for reductant between the NOx coming from nitrate decomposition and that needed for catalyst reduction requires a 3:1 excess (id est an approximate ratio of two between the quantity of reductant injected and the amount of NOX adsorbed during lean phase operations)

Notes:

Vendor supplied data

Publisher Number:

1999-01-3502

Access Restriction:

Restricted for use by site license