Coals and most solid carbons have the tendency to chemisorb oxygen already at low and moderate temperatures. This phenomenon was investigated in the past since it was considered responsible of self-ignition of coal stockpiles, however it encountered renewed interest recently, after being recognized as a key step in some innovative processes of clean coal combustion [1] . The present work addresses the effects of mild oxidation on the properties of a suite of coals of different rank and origin. The experimental campaign was based on a set of different techniques such as Raman spectroscopy, Electron Paramagnetic Resonance (EPR) spectroscopy, powder X-Ray Diffraction spectroscopy (XRD), porosimetric and thermogravimetric analysis. Results are analysed and discussed in order to highlight the effects of mild oxidation on the distribution and population of active sites on the carbon surface, the degree of order of the carbonaceous structure, in particular the amorphous vs crytstalline fraction, the porosity and accessibility of the internal surface area, ultimately reactivity and thermochemistry of coal combustion.
EFFECT OF MILD OXIDATION ON THE STRUCTURE AND PROPERTIES OF COALS
Osvalda SENNECA;Luciano CORTESE;
2015
Abstract
Coals and most solid carbons have the tendency to chemisorb oxygen already at low and moderate temperatures. This phenomenon was investigated in the past since it was considered responsible of self-ignition of coal stockpiles, however it encountered renewed interest recently, after being recognized as a key step in some innovative processes of clean coal combustion [1] . The present work addresses the effects of mild oxidation on the properties of a suite of coals of different rank and origin. The experimental campaign was based on a set of different techniques such as Raman spectroscopy, Electron Paramagnetic Resonance (EPR) spectroscopy, powder X-Ray Diffraction spectroscopy (XRD), porosimetric and thermogravimetric analysis. Results are analysed and discussed in order to highlight the effects of mild oxidation on the distribution and population of active sites on the carbon surface, the degree of order of the carbonaceous structure, in particular the amorphous vs crytstalline fraction, the porosity and accessibility of the internal surface area, ultimately reactivity and thermochemistry of coal combustion.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
