Catalytic DeNOx for Marine Diesel Emission Control: SCR Technology / Valutazione di sistemi di abbattimento degli ossidi di azoto prodotti da motori diesel marini, integrato con le tecnologie di scrubbing di gas acidi e plasma non termico

The operation temperature windows of commercial industrial catalysts for NH3-SCR of NO (WO3-V2O5/TiO2 and MoO3-V2O5/TiO2) is 300-400 °C. As such, the SCR unit have to be located upstream of the desulphurizer and the particulate control device to avoid reheating of the flue gas. This makes these catalysts susceptible to deactivation from high-sulfur and high-dust. Therefore, it is a great interest to develop active low temperature SCR catalysts that could be placed downstream of the flue gas desulphurization and particle removal. Consequently, widespread attentions have been paid to the development of low-temperature SCR catalysts in recent years for tail-end configurations. The advantages of tail-end configurations include catalyst exposure to a relatively clean flue gas, more space to accommodate any changes in the power cycle or fuel, a decrease in catalyst volume and cost as the result of the cleaner flue gas, and an increase in catalyst life. Nevertheless, the special tail-end configuration of the Deecon FP7 project, after the ESWS unit, entails the possible exposure of the catalyst to alkaline metals contained in the flue gas from the scrubber. In this report the most promising catalytic solutions proposed in the open literature for a SCR operation at low temperature and in the presence of alkali and alkali earth metals are examined and a research activity aimed at testing novel catalytic formulations under conditions simulating those supposed for a tail end configuration is presented.