TG/DSC and kinetic parametrization of the combustion of agricultural and forestry residues

Abstract

The present paper discusses the data obtained from the thermogravimetric analysis and kinetic evaluation of seven different experimental solid biomasses representative of the Euroregion Galicia-North Portugal and commonly found in Europe. The samples comprised three raw, nonwoody biomasses and four additivated batches blended with kaolin and calcium carbonate. A TG-DSC analysis was performed on each sample under an oxidative atmosphere and three heating ratios, and the additives were found to increase the duration of the oxidation of carbon, its heat release, and displaced the reaction of volatile compounds to higher temperatures, while at the same time decreasing the peak heat emission caused by the volatiles up to a 40%. Three isoconversional methods, namely, Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose and Friedman were utilized to determine the activation energy and pre-exponential factor of the fuels, both globally and at intervals during conversion, and the results were found to be similar among the three methods, with values ranging from 47.07 kJ/mol to 228.31 kJ/mol for conversion degrees between 0.1 and 0.9. Fuels mixed with the additives mentioned exhibited lower activation energy values than their raw counterparts, suggesting an enhancement of the combustion conditions.