Evaluation of orange and potato peels as an energy source: a comprehensive study on their pyrolysis characteristics and kinetics

Abstract

The orange and potato peels can be evaluated as raw materials in pyrolysis process to produce sustainable fuels and chemicals. The present study focuses on determining pyrolysis characteristics and kinetics of orange and potato peels. Thus, thermogravimetric analyses of said peels were studied from ambient temperature to 650°C at 2, 10 and 15°C/min heating rates under N2 atmosphere. The studies revealed that the thermal decomposition of orange peels occurs in four stages whereas potato peels decompose in three stages. The second and third stages of orange peel pyrolysis and the second stage of potato peel pyrolysis were determined as active pyrolysis stages. The kinetic parameters of active pyrolysis stages were calculated by direct Arrhenius plot, Coats-Redfern, Friedman and Kissinger-Akahira-Sunose methods. The average activation energies calculated by all methods were relatively in good agreement for second stages, but the same cannot be said for the third stage of orange peel pyrolysis. Considering the conversion values based on volatiles and the calculated average activation energy values, the orange and potato peels were projected to be valuable and sustainable energy sources which can be evaluated by pyrolysis process.