Differences between combustion and oxy-combustion of corn and corn–rape blend using thermogravimetric analysis

Nowadays, diverse technologies to produce electricity based on bioresidues are investigated in order to reduce the external energy dependence of occidental countries, as Spain. Thermogravimetric analysis was used to study and compare the combustion and oxy-combustion of corn, rape and a corn–rape blend. Non-isothermal thermogravimetric data were used to obtain the reaction kinetics of these bioresidues. This paper reports on the application of the Vyazovkin and Ozawa–Flynn–Wall isoconversional methods for the evaluation of kinetic parameters (energy activation, pre-exponential factor and order of reaction) for the oxidation of the biomasses studied. Differences were found in the TG curves in accordance with the proximate analysis results for the cellulose, hemicellulose, lignin, volatile matter and fixed carbon content of biomasses and the atmosphere of the reaction. The presence of CO2 in the atmosphere instead of N2 was also discussed. The activation energy obtained from corn (153.0kJ/mol) combustion was lower than that obtained from corn oxy-combustion (168.6kJ/mol). However, corn–rape blend oxidation was more favourable in the presence of CO2 (E ~155.3kJ/mol) than in N2 (E ~155.9kJ/mol). Both Vyazovkin and Ozawa–Flynn–Wall methods yielded similar results. •The effects of CO2 in oxidation of corn, rape and its blend are studied.•Differences between CO2 and N2 in oxidation atmosphere are discussed.•Two isoconversional kinetic models are proposed to obtain kinetic parameters.•Kinetic parameters are calculated to improve equipment design investigation.•The blending of corn–rape improves the oxy-combustion of individual biomasses.