Formation and Elimination of Pollutant during Sludge Decomposition in the Presence of Cement Raw Material and Other Catalysts

The use of a waste-based secondary fuel in clinker kilns is a widely used practice. Nevertheless, specific studies to understand the destruction mechanism of exhaust pollutants in cement raw material (CRM) are limited. This work focuses on the possible catalytic effect of the interaction of exhaust gases from the combustion of sewage sludge with various solids beds, including CRM. Catalyst based on vanadium pentoxide and deNOx commercial catalyst, based on Ti/Zr/Pt, were used. The behaviors of volatile compounds, polycyclic aromatic compounds and dioxins and furans are analyzed in the presence or absence of the different materials. Some compounds are produced when interacting the pollutants with the beds, and some others are destroyed. Results show that the presence of CRM at the outlet of the combustion gases is beneficial for the decrease in pollutant emission, confirmed by a catalytic effect of CRM at medium temperatures.