Nitrous Oxide Destruction in Contact with Metallic Iron

Abstract

This article presents the results of the investigation of nitrous oxide reduction by reaction with metallic iron, within the temperature range of 600–850 °C. Experiments were carried out in a one-dimensional tubular flow reactor externally heated in an electrical furnace. The spherical iron samples of well-defined and fixed surface area were placed in the center of the reactor, and mixtures of N₂O/N₂, N₂O/O₂/N₂, and N₂O/CO₂/N₂ of different molar fractions of compounds were passed through the reactor. On basis of these experiments the values of the reaction rate constant for the decomposition of N₂O on Fe were evaluated and compared with the literature data. An impact of oxygen on inhibition of deN₂O process was investigated. A very strong and fast decrease of N₂O reduction rate was observed after introducing more than 2 vol% O₂-containing gas mixture into reaction zone. The surfaces and cross sections of partly oxidized iron samples were observed using the scanning and light microscopes. The structure of the iron oxides formed during iron oxidation in reaction with N₂O is discussed.

Keywords:

• Iron oxidation
• N₂O reduction
• Reaction rate

ACKNOWLEDGMENTS

This work has been partially supported by the Ministry of Science and Higher Education in Poland under Project No. 3 T10B 031 30. Additionally, we thank Józef Popowicz for scientific support in the mass transfer issues.