Catalytic Combustion of Tannery Sludge in a Rotating Reactor

Vincenzo Vaiano*, Diana San

Abstract

This work is focused on the catalytic combustion of tannery sludge by using ferrites and CeO2 in a stainless steelfixed bed reactor in comparison with the same system set in rotation. The presence of catalysts determined an increase of the reactivity with respect to the sludge alone. CeO2 catalystenhanced mainly the reaction rate associated to the combustion of volatiles while it is not active in the combustion ofthe char. On the contrary, both LaFeO3 and LnFeO3 perovskites have accelerated the latter step. In the case ofsludge alone, passing from the fixed to the rotating reactor, the mass of carbon burned increased from 18 wt% to 31wt% indicating that the related effect is the promotion of mass transfer rates among the different phases. Moreoverthe ratio CO/CO2 widely decreased in the rotating system demonstrating that the enhanced oxygen mass transferfrom gas to sludge particle surface determined an improvement of the combustion process since the selectivity toCO2 is enhanced. Keywords: Catalytic combustion; Tannery sewage sludge; Rotating reactor.