Vol.:(0123456789) 1 3 Journal of Thermal Analysis and Calorimetry https://doi.org/10.1007/s10973-020-10055-9 Pyrolysis characteristics and kinetics of sour cherry stalk and fesh via thermogravimetric analysis using isoconversional methods Gözde Gözke 1  · Korkut Açıkalın 2 Received: 22 November 2019 / Accepted: 6 July 2020 © Akadémiai Kiadó, Budapest, Hungary 2020 Abstract Pyrolysis characteristics and kinetics of sour cherry stalk and fesh were investigated using non-isothermal thermogravi- metric analysis at fve diferent heating rates of 5, 10, 20, 30 and 40 °C min −1 . Activation energies at two diferent 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 fesh 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 efect of the particle size of the applied biomass on pyrolysis kinetics as well as the possibility of using sour cherry stalk and fesh as renewable feedstock for alternative energy source. Keywords Sour cherry stalk · Sour cherry fesh · Pyrolysis kinetics · Isoconversional methods · Multistage process Introduction Increasing energy demand and the depletion of fossil fuels as well as environmental issues originating from the utiliza- tion of fossil fuels led an increase in the search of alterna- tive energy sources [1]. Biomass being a renewable energy source has initiated a major interest over the past decades due to the advantages such as availability, sustainability and environment-friendly concerns [2]. In other words, biomass is available abundantly on earth while preserving essential ecosystem functions and can reduce the carbon dioxide con- centration in the atmosphere and releases less sulfur and nitrogen oxides when used as combustion material [3]. Biomass originated energy covers a considerable amount of energy need in the world [4]. Main biomass sources include agricultural residues such as stalks, husks and straw; forest residues such as residual wastes from logging and thinning processes; waste of diferent origins such as from municipal, agricultural and industrial extractions; and energy crops such as oilseeds, sugar crops and algae [5]. Potential use of biomass as renewable energy resource depends on the feedstock properties and process parameters [6, 7]. Thermochemical conversion methods, such as pyroly- sis, combustion and gasifcation, are the commonly pre- ferred processes to produce energy from biomass. Among these methods, pyrolysis is the most preferred approach resulting from lower temperature requirement, lack of oxi- dizing agents in the process and higher quality fnal prod- ucts compared with aforementioned methods [8]. Pyroly- sis is a thermal degradation process in which biomass is converted into valuable biofuel in the absence of oxygen at a temperature range between 350 and 700 °C [9]. As a * Gözde Gözke gozde.gozke@yalova.edu.tr 1 Department of Chemical Engineering, Faculty of Engineering, Yalova University, Yalova, Turkey 2 Department of Energy Systems Engineering, Faculty of Engineering, Yalova University, Yalova, Turkey