Investigation of the Performance of Fe-Based Catalysts for NOx Reduction with NH3

Selective catalytic reduction (SCR) with ammonia is a well-proven technique for NO_x removal in power stations. It is very effective in NO_x reduction with an efficiency up to 98%. However, the current SCRs have a limitation on operation temperature and a narrow operation temperature window. Metal Fe based catalysts were used in the investigation to improve the low temperature performance of NO_x conversion. The temperature range studied was between 150degC and 350degC with an interval of 50degC. The honeycomb catalysts were prepared by an impregnation method. The study also included characterization of catalysts by XRD, H₂-TPR and SEM methods. It is found an increase in metal Fe content from 2 to 6% wt. offers an improvement in the catalytic performance. However, a further increment in Fe content will result in a decrease in its performance. More than 90% NO_x conversion rate could be achieved over the Fe-based honeycomb catalyst at a low temperature by doping the catalysts with Ni and Zr at different weights. Among all the catalysts studied, the mixed metal catalyst of Fe-Ni-Zr is found the most potential one, not only because of its higher NO_x conversion rate at a low temperature, but also because of its wider operation temperature window.