Effect of CO_2/O_2 on Catalytic Reduction of NO by Iron

摘要

This paper presents the results of the reaction between metallic iron mesh rolls and NO in the presence of CO_2/O2 at different temperatures. All experiments were carried out in a ceramic tube controlled by the temperature programmed electrical furnace. About 99% NO reduction was achieved when temperature was above 700°C in the absence of CO_2/O2. Results showed that CO_2 in the flue gas had little effect on the NO reduction. NO reduction efficiencies were observed to exceed 95% for all CO_2 concentrations at above 700°C. The addition of O_2, however, caused a sudden drop by about 76% in NO reduction efficiency. Scanning electron microscope (SEM) results showed that the oxidation of iron in O_2 atmosphere led to a more continuous and impervious oxide layer than that in CO_2 atmosphere. Results using X-ray diffraction (XRD) to detect the iron samples after reactions revealed that FeO, Fe_3O_4 Fe and Fe_2O_3 were formed in CO_2 atmosphere, but and Fe_2O_3 were formed when O_2 was added.