Arrhenius Kinetic Analysis during Combustion of Spirulina platensis Microalgae

摘要

Characteristics and potential of microalgae Spirulina platensis as an energy source were studied in regard to the decomposition patterns, as well as kinetic and thermodynamic parameters. The thermogravimetric analysis was performed using the TGA instrument (Mettler Toledo TG DSC 1) at a heating rate of 30 °C/min, with an atmospheric air flow-rate of 100 ml/min at the temperature range of 25-1000 °C. The kinetic was evaluated using a differential method of Arrhenius. The results showed that Spirulina platensis microalgae decomposed into three stages. The first stage is related to the evaporation of moisture, the second stage is associated with the release of volatile matter, and the final stage is the combustion stage of char. The kinetic evaluation resulted in the respective activation energy (E), pre-exponential factor (log A) and reaction order (n) are 53.57 kJ/mol, 4.4 min~(-1), and 1.73. It also understands from the thermodynamic analysis that the respective values of enthalpy (AH), Gibbs free energy (AG) and the entropies (AS) were 48.50 kJ/mol, 146,73 kJ/mol, and -174,78 J/mol.