Emission control of household heating combustion units via catalytic oxidation: A Pt-Pd monolith case

Among the most energy and cost-efficient flue gas after-treatment technologies is the catalytic oxidation of harmful emissions including carbon monoxide and organic gaseous compounds (OGC). The present work aims to shed light on the transition of lab-scale research under ideal conditions toward realistic experiments focusing on the catalytic oxidation of carbon monoxide (CO), as the simplest pollutant via Pt-Pd monolithic catalyst. The catalytic testing demonstrated that the conversion curves could be divided into three major, almost linear parts (A, B and C) and two transition parts, with part B being much steeper, implying that a minor change in flue gas temperature causes a significant change in CO conversion rate. Part B is considered as a measure of the catalytic activity considering that the steeper the increase the better the catalytic performance as it approaches the full conversion. The comparison of the conversion curves of the artificial and realistic flue gas experiments demonstrated a shift towards higher temperatures (30 – 40 °C) in part B, indicating that in the realistic flue gas, there are inhibiting factors such as water vapour and/or CO_2, especially at lower temperatures (<200 °C) where the adsorption process of these species is favoured.