Thermal behavior, thermodynamics and kinetics of co-pyrolysis of binary and ternary mixtures of biomass through thermogravimetric analysis Articles uri icon


published in

publication date

  • November 2020

start page

  • 1

end page

  • 13


  • 280

International Standard Serial Number (ISSN)

  • 0016-2361

Electronic International Standard Serial Number (EISSN)

  • 1873-7153


  • The present study aims to investigate the co-pyrolysis behaviors, kinetics and thermodynamics of spirulina microalgae, sugarcane bagasse and waste tire, and their mixtures, by means of thermogravimetric analysis. Various Isoconversional methods, specifically Flynn-Wall-Ozawa (FWO), Kissinger-AkahiraSunose (KAS), Starink (STK) and Vyazovkin (VYA), the compensation effect and master plots were implemented to evaluate the kinetic parameters. Furthermore, by comparing experimental and theoretical values of mass loss, it was concluded that for the microalgae-bagasse mixture, the interaction is synergistic. In other cases, inhibitive interaction has been observed. Due to tire composition and its tough structure, the tire had the highest activation energy and the addition of tire to the binary mixture increased the activation energy of ternary mixtures. The average activation energy obtained for Spirulina, bagasse and scrap tires is around 200, 90 and 230 kJ mol-1, respectively. However, the average activation energy of their ternary mixture is approximately 165 kJ mol-1. Thermodynamic parameters (DeltaG, DeltaH and DeltaS) were estimated based on kinetic data using the thermogravimetric relations. The endothermic character of the pyrolysis process was proved by the positive values of DeltaH, obtaining an average value of 160.5 kJ mol-1 for the ternary mixture. The Gibbs free energy DeltaG of the ternary mixture is quite uniform with the conversion, varying slightly between 173 and 176 kJ mol-1. In contrast, DeltaS depends strongly on the pyrolysis conversion, obtaining negative values for conversions below 0.4 for the ternary mixture, whereas positive values are attained for conversions above 0.6.


  • biomass; co-pyrolysis; kinetic modeling; thermal behavior; thermodynamic parameters