Diesel Soot Oxidation with NO₂:  Engine Experiments and Simulations

Abstract

The diesel particulate filters (DPFs) technology has impressively advanced especially during the last years, driven by the interest in the reduction of automobile particulate emissions. This paper is concerned with the effect of NO 2 as an active oxidation agent in the regeneration process of the soot accumulated in the particulate filter. Experiments at realistic conditions using a diesel engine equipped with a standard oxidation catalyst and a particulate filter are carried out at a wide range of operating conditions. These results are used to validate an already available mathematical model of the NO 2 -assisted regeneration phenomena in the particulate filter. The combined use of experimental and modeling results provides interesting conclusions regarding the significance and the chemistry of the reaction of soot with NO 2 . The advantages and drawbacks of such an approach compared to standard laboratory synthetic gas studies are discussed. The agreement between experimental and simulation results in terms of engineering interest (rate of soot accumulation or depletion) is quite satisfactory and indicates that such a type of model could be a promising design tool.

Opportunities for ceria-based mixed oxides versus commercial platinum-based catalysts in the soot combustion reaction. Mechanistic implications

“…This is in agreement with other authors, such as Stanmore et al [2], who found similar activation energy for this reaction (50 kJ/mol), Kandylas et al [50], who reported 40 kJ/mol, and also Lee et al, reporting 44 kJ/mol [40]. This fact is in accordance with the idea that NO 2 is much more active than O 2 and can directly attack the carbon surface [28].…”

Modelling and Simulation of Filtration, Regeneration and Deposit Rearrangement Effects in Gas Filter Systems Examplified by a Diesel Soot Filter

“…Im Gegensatz zur thermischen Regeneration wird er hier genutzt, um den Anteil des im Abgas enthaltenen Stickstoffdioxids NO 2 durch Oxidation des ebenfalls im Abgas enthaltenen Stickstoffmonoxids NO zu erhöhen. Durch NO 2 kann eine Oxidation des Rußes bereits ab Temperaturen von 250°C erfolgen [9].…”

“…In Abb. 9 Bei Verwendung eines Additiv-Systems erhöht sich durch jede thermische Regeneration, bzw. bei der kontinuierlichen Regeneration durch zunehmende Betriebszeit, die im DPF eingelagerte Aschemasse.…”

Measurements of diesel soot oxidation kinetics in an isothermal flow reactor–catalytic effects using Pt based coatings

“…Soot oxidation is modeled by two parallel reactions with O 2 and NO 2 , [8,9]. The respective rate expressions are also shown below.…”