An investigation into catalysts to improve low temperature performance in the selective catalytic reduction of NO with NH_3

摘要

Selective catalytic reduction with NH3 is considered one of the most effective technologies controlling NOx emission. Metal Fe-based catalysts were used in the investigation to improve low temperature performance of NOx conversion. The temperature range studied was between 150℃ and 350℃ in increments of 50℃. The honeycomb catalysts were prepared by an impregnation method. The study also included characterisation of catalysts by BET, XRD, H_2-TPR and XPS methods.rnIt was found that an increase in metal Fe content from 2 to 6% wt offered an improvement in the catalytic performance. However, a further increase in Fe content resulted in a decrease in its performance. More than 90% NOx conversion rate could be achieved over the Fe-based honeycomb catalyst at a low temperature by doping with different weights of Ni and Zr metals. Amongst all the catalysts studied, the mixed metal catalyst of Fe-Ni-Zr was the one with most potential. This was because of its higher NOx conversion rate at a low temperature and also because of its wider operating temperature window. The effect of gas hourly space velocity (GHSV) was also investigated and the results showed that as GHSV increased, the reduction of NOx decreased.