Kinetic analysis of non-catalytic and Mn-catalysed combustion of diesel soot surrogates

The kinetics of the combustion process of two carbon blacks, selected as diesel soot surrogates, namely, Flammruss 101 and Printex XE-2B, was investigated by dynamic thermogravimetry in an excess of air. The kinetic parameters (activation energy and pre-exponential factor) were accurately calculated by different processing methods, such as Kissinger-Akahira-Sunose isoconversional method and Coats-Redfern model-fitting method. Manganese (as manganese oxide) added to diesel soot surrogates, strongly decreased the ignition temperatures by 150-200 degrees C. The activation energy of the catalytic process was lowered by about 15 and 10 kJ mol(-1) for Flammruss 101 and Printex XE-2B sample, respectively, with respect to the non-catalytic oxidation. The effectiveness of carbon-catalyst contact appeared to strongly affect the catalytic performance. Thermal experiments confirmed that, on one hand, impregnation markedly increased the reactivity in comparison with a simple physical mixture, and on the other hand, a highly porous structure of the parent carbon material enhanced the catalytic role of the active phase. (c) 2005 Elsevier B.V. All rights reserved.