Pyrolysis characteristics and kinetics of sour cherry stalk and flesh via thermogravimetric analysis using isoconversional methods

Abstract

Pyrolysis characteristics and kinetics of sour cherry stalk and flesh were investigated using non-isothermal thermogravimetric analysis at five different heating rates of 5, 10, 20, 30 and 40 °C min⁻¹. Activation energies at two different particle size ranges were determined from the experimental data using various isoconversional methods, namely Friedman, Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose methods. Four stages were observed during the pyrolysis process in which the second and the third stage were determined as active decomposition stages. Average activation energies of sour cherry stalk with a particle size of 75–150 µm were calculated in the range of 159.0–160.5 kJ mol⁻¹ and 118.8–141.1 kJ mol⁻¹ at the second and the third active stage, respectively. The same type of biomass with a particle size of 150–250 µm revealed average activation energies in the range of 179.7–180.0 kJ mol⁻¹ and 162.1–164.6 kJ mol⁻¹ at the second and the third active stage, respectively. Average activation energies of sour cherry flesh with a particle size of 75–150 µm were calculated in the range of 136.2–160.5 kJ mol⁻¹ and 133.7–151.2 kJ mol⁻¹ at the second and the third active stage, respectively. The same type of biomass with a particle size of 150–250 µm resulted in average activation energies in the range of 266.1–273.9 kJ mol⁻¹ and 179.8–197.8 kJ mol⁻¹ at the second and the third active stage, respectively. Besides the obtained activation energy values, results demonstrated the effect of the particle size of the applied biomass on pyrolysis kinetics as well as the possibility of using sour cherry stalk and flesh as renewable feedstock for alternative energy source.