Abstract
Bioenergy potential of microalage Scednedesmus quadricuda through pyrolysis was investigated using kinetic and thermodynamic analyses. From model-free isoconversional methods, the estimated average activation energies were 152.37 (+/- 20.93), 174.98 (+/- 22.38), and 153.00 (+/- 21.23) kJ/mol, using Friedman, OFW and advance Vyazovkin methods, respectively. Avrami-Erofeev's A1/4 reaction model was the most probable single-step re-action mechanism determined from the combined kinetic analysis. The activation energy profile, however, indicated a complex degradation process in the active pyrolysis zone. Two independent parallel reactions were considered in the active pyrolysis zone. Average activation energy for low temperature conversion was 77.95 (+/- 3.12) kJ/mol, pre-exponential coefficient 4.86E4 (+/- 2.24E4) s(-1), and n = 1.51 (+/- 0.10), whereas for high temperature conversion, the activation energy was 73.26 (+/- 17.93) kJ/mol, pre-exponential coefficient 1.32E3 (+/- 2.61E3) s(-1), and n = 1.21 (+/- 0.16). Thermodynamic analysis of pyrolysis in terms of enthalpy, Gibbs free energy, and entropy indicated the feasibility of conversion.