Exploring bioenergy potential and thermal behavior of Elephant grass cultivated with treated microalgae wastewater for advanced pyrolytic products

Abstract

This research investigates the thermal decomposition of Elephant Grass (EG) utilizing effluent treated through a microalgae-based membrane bioreactor. The focus was on understanding the thermal degradation properties under different heating rates ranging from 10 to 40 ℃/min. The primary decomposition products identified were hydrogen (H2), methane (CH4), water vapor (H2O), carbon dioxide (CO2), and various hydrocarbons. Kinetic analyses, employing three distinct model-free methodologies, determined the activation energy values to be 145 kJ/mol and 155 kJ/mol. Further, thermodynamic assessments revealed enthalpy changes (ΔH) around 148 kJ/mol and 138 kJ/mol, and Gibbs free energy changes (ΔG) approximately 742 kJ/mol and 769 kJ/mol. These values underscore the viability of EG as a renewable and sustainable energy source. The study noted that the degradation sequence predominantly follows the order: lignin, cellulose, hemicellulose, and then water. Advanced predictive models, specifically boosted regression trees, demonstrated effective prediction capabilities for thermal degradation processes. Overall, this study accentuates the potential of EG as an environmentally friendly alternatives to conventional fossil fuels, thereby encouraging waste valorization and aiding in the reduction of carbon emissions.