One of the main pollutants in automobile engine exhausts is NO. Hydrocarbon-based selective catalytic reduction (HC-SCR) is one of the most preferred methods to reduce NO at the expense of unburned hydrocarbons, which are also present in automobile exhausts. In this study, we have developed a detailed kinetic model and analyzed the selectivity of NO reduction to various products (N2, N2O, and NO2). The optimal operating conditions for the maximum reduction of NO to N2 are also explored. Various phenomena including coking and the oxygen-rich nature of the catalyst surface are found to occur as the amount of oxygen in the inlet is varied. The influence of O2 and temperatures on the selectivity of NO reduction is discussed in detail. © 2017 American Chemical Society.

Preeti Aghalayam

Department Of Chemical Engineering

Vishnu S. Prasad

CATALYSTS

EXHAUST SYSTEMS (ENGINE)

Hydrocarbons

Nitrogen oxides

reduction

After-treatment

AUTOMOBILE EXHAUST

Catalyst surfaces

Detailed kinetic modeling

Microkinetic modeling

OPTIMAL OPERATING CONDITIONS

Pt catalysts

UNBURNED HYDROCARBONS

Selective catalytic reduction

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Industrial and Engineering Chemistry Research

Nitric oxides and unburned hydrocarbons from automotive engines are major atmospheric pollutants. A strategy based on the simultaneous reduction of NO and oxidation of hydrocarbon can be very effective in aftertreatment. In this study, the various regimes of operation of this selective catalytic reduction process using propene as a representative hydrocarbon, with and without the presence of oxygen, are delineated. Detailed kinetic modeling using quantitative microkinetics for Pt and Rh catalysts is performed. Interesting catalytic features including coking and oxygen poisoning are clearly identified. An optimal operating regime in which the complete conversion of NO and C3H6 occurs in the presence of small amounts of oxygen is highlighted. © 2016 American Chemical Society.

Microkinetic Modeling of the Effects of Oxygen on the Catalytic Reduction of NO on Pt and Rh in Automotive Aftertreatment

Journal of Environmental Chemical Engineering

A comparative study of the H2-assisted selective catalytic reduction of nitric oxide by propene over noble metal (Pt, Pd, Ir)/γ-Al2O3 catalysts

ChemInform

ChemInform Abstract: Performance of Platinum-Group Metal Catalysts for the Selective Reduction of Nitrogen Oxides by Hydrocarbons.

Applied Catalysis B: Environmental

A comparative study of the selective catalytic reduction of NO by propylene over supported Pt and Rh catalysts

In order to meet the stringent regulatory norms of NOx and CO emitted by automobiles, reduction of these pollutants has become an intense field of research. Various catalysts like Pt, Rh, Ir, Cu, and Fe have been found to possess high activity for the reduction of NO. However, the available detailed surface reaction mechanisms are not satisfactory in clarifying all the aspects of the simultaneous reduction of NO and oxidation of CO. Here we have developed a quantitative surface reaction mechanism based on elementary steps, in order to comprehend the phenomena of catalytic reduction of NO by CO. Eleven elementary steps are proposed for the NO-CO and NO-CO-O2 systems on Pt group catalysts. The elementary reaction mechanism is coupled with the continuously stirred tank reactor/packed bed reactor models and the simulation results are validated against literature experiments for the NO-CO reaction on Pt, and the NO-CO-O2 reaction on Ir catalyst. Despite the simplicity, the CSTR model is able to capture the observed phenomena well on Pt and Ir catalysts. The effect of O2 on the activity of CO for NO reduction is also analysed in detail through the simulations. © 2006 Elsevier B.V. All rights reserved.

Catalysis Today

Detailed surface reaction mechanism for reduction of NO by CO

Microkinetic Modeling of HC-SCR of NO to N2, N2O, and NO2 on Pt Catalysts in Automotive Aftertreatment

Journal	Data powered by TypesetIndustrial and Engineering Chemistry Research
Publisher	Data powered by TypesetAmerican Chemical Society
ISSN	08885885
Open Access	No