Study of pequi peel pyrolysis: Thermal decomposition analysis and product characterization

Highlights: • Pequi peel pyrolysis process is feasible for the use of this agro-industrial waste. • The main compounds of the bio-oil were ketones, furans, acids, alcohols and phenols. • Pyrolysis products proved to be future sources of energy. • Pyrolysis products may be likely sources of raw materials for chemical industry. The consumption of pequi generates a considerable amount of waste (peel) which is not used efficiently. Pyrolysis can be a viable alternative for the use of this food waste, by converting pequi peel into energy in the form of biofuels and compounds of great interest to the chemical industry. This study evaluates the potential of pequi peel waste in the production of bioenergy through pyrolysis and characterization of the obtained products. The biomass was characterized and revealed to be a viable raw material for pyrolysis. From thermogravimetry (TG) data, we determined kinetic parameters according to Friedman's global reaction and Flynn-Wall-Ozawa (FWO) models, which led to the mean experimental value of activation energy (E_a) of 239.2 and 224.4 kJ mol⁻¹, respectively. The pyrolysis was carried out at 400, 500 and 600 °C, and the highest bio-oil yield (43.6%) was obtained at 500 °C. The classes of compounds quantified in higher amount in the bio-oils were ketones, furans, acids, alcohols and phenols. The bio-oil compounds from pequi peel pyrolysis can be a source of energy and raw materials of great interest for the chemical industry to produce high-added value products. The biochar shows potential for application as adsorbent and solid fuel. The pyrolysis is a feasible process for the pequi peel waste by adding value and reducing the environmental impact caused by the inadequate disposal of lignocellulosic materials.