Pyrolysis and co-pyrolysis of greenhouse-based agricultural wastes by TGA

Abstract The aim of this study was to investigate the bioenergy potential of greenhouse vegetable wastes like tomato, pepper, and eggplant wastes individually, in equal-mass binary mixtures, and in equal-mass ternary mixtures under pyrolysis conditions using thermogravimetric analysis (TGA). The TGA experiments were carried out in a nitrogen gas flow rate of 100 ml min −1 , at heating rates of 10, 20, and 30 °C min −1 , and temperature range of 850 °C–900 °C. For the seven biomass samples activation energy ( E a) and thermodynamic parameters were determined using the Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, and STR kinetic models. It was observed that the decomposition temperature of biomass samples during pyrolysis or co-pyrolysis ranged between 125 and 695 °C, and the corresponding mass loss was significantly high, ranging from 59% to 78.2%. In terms of E a, tomato waste as a single biomass (83.67–89.21 kJ mol −1 ), and in binary mixtures with pepper (69.41–75.68 kJ mol −1 ) and eggplant (71.41–77.65 kJ mol −1 ), was found to be a competitively viable biomass source compared to other biomasses studied in this work and in the literature. In the study, the Δ H (change in enthalpy) value for the pyrolysis reaction of tomato was calculated to be between 78.49 and 84.03 kJ mol −1 , while the Δ H values for the co-pyrolysis reactions of tomato-pepper and tomato-eggplant were calculated to be between 64.37–70.64 kJ mol −1 and 66.39–72.63 kJ mol −1 , respectively. It was determined that the tomato, tomato-pepper, and tomato-eggplant samples were more competitive compared to the other samples in terms of the energy requirements of the pyrolysis or co-pyrolysis reactions.