Catalytic oxidation of NO to NO2 for nitric acid production over a Pt/Al2O3 catalyst
Journal article, 2018

The oxidation of nitric oxide (NO) to nitrogen dioxide (NO2) is a key step both in NOx abatement technologies as well as in the Ostwald process for nitric acid production. A 1 wt.% Pt/Al2O3catalyst was used to study oxidation of nitric oxide at two different concentrations of NO; 400 ppm NO (representative of engine exhaust treatment) and 10% NO (nitric acid plant). The catalyst was characterised using N2adsorption and CO chemisorption. The effect of temperature and feed concentration on catalytic activity was investigated. For a feed comprising of 10% NO and 6% O2, Pt/Al2O3exhibits significant catalytic activity above 300 °C. Addition of 15% H2O in the feed had an insignificant effect on activity of the catalyst. We report for the first time the kinetics for oxidation of NO to NO2under nitric acid plant conditions. An apparent activation energy of 33 kJ/mol was observed. The rate equation for the overall reaction was determined to be r=kfKG(PO2)0.5, where kfis the forward rate constant. The reaction is independent of NO concentration while it has half order dependency on oxygen. The reaction mechanism which fits our experimental observation consists of dissociative adsorption of oxygen, associative adsorption of nitric oxide with desorption of nitrogen dioxide as the rate limiting step.

Ostwald process

Reaction order

NO oxidation

Kinetics

Nitric acid

Pt/Al2O3

Author

Ata ul Rauf Salman

Norwegian University of Science and Technology (NTNU)

Bjørn Christian Enger

Sintef Foundation for Scientific and Industrial Research At the Norwegian Institute of Technology

Xavier Auvray

Norwegian University of Science and Technology (NTNU)

Competence Centre for Catalysis (KCK)

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Chemical Engineering Design

Rune Lødeng

Sintef Foundation for Scientific and Industrial Research At the Norwegian Institute of Technology

Mohan Menon

YARA Technology Center

David Waller

YARA Technology Center

Magnus Rønning

Norwegian University of Science and Technology (NTNU)

Applied Catalysis A: General

0926-860X (ISSN) 1873-3875 (eISSN)

Vol. 564 142-146

Subject Categories

Other Chemical Engineering

Biocatalysis and Enzyme Technology

Organic Chemistry

DOI

10.1016/j.apcata.2018.07.019

More information

Latest update

8/15/2018