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Global warming and the GHG effect have forced the reduction of the energetic dependence on fossil fuels. Because of that, research focusing on biomass properties, characteristics and energetic conversion has increased in the last decades. The present study was carried out in terms of determination of kinetic parameters, focusing on two different energetic conversion processes: pyrolysis, carried out under nitrogen atmosphere, and oxygen-enriched combustion, using an atmosphere of air enriched with 30% oxygen. Three different lignocellulosic biomass samples were used. Thermogravimetric analysis was performed using four different heating rates in order to carry out a kinetic analysis using model free methods (Friedman, Kissinger-Akahira-Sunose, and Flynn-Wall-Ozawa). The results showed that oxygen-enriched combustion produced a more complete reaction with low char values and activation energy values greater than pyrolysis values. Among the kinetic methods, Friedman reported the most different values, acceptable for pyrolysis process but not so much for oxygen-enriched combustion. [ABSTRACT FROM AUTHOR]

Slow pyrolysis (gradual heating over a wide range of temperatures) characteristics of various biomasses (corn brakes, wheat straw, and hazelnut shell) were investigated by simultaneous thermal analysis (STA-TGA-DTG-DSC), coupled with mass spectrometry. Thermal decomposition of these samples was divided into three stages corresponding to removal of water, devolatilization, and formation of bio-char. It was found that differences in thermal behavior of the samples are due to differences in their composition. The mass spectrometry results showed that H2, CH4, H2O, CO2 (C3H8), CO, and C2H6 were main gaseous products released during pyrolysis. Within the pyrolysis processes, it was found that CO2 can be used on the large scale for production of CO-rich syngas. [ABSTRACT FROM AUTHOR]