Browsing by Author "Alshahranib, Hassan"

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    Sustainable renewable biofuel production toward pyrolysis of fibers biowaste Agave Americana L. and thermodynamics mechanisms kinetic parameters triplet assessment
    (Journal of Natural Fibres, 2025-07-26) Lalaymiaa, Imen; Belaadi, Ahmed; Alshahranib, Hassan; Ghernaoutc, Djamel; Mukalazie, Herbert
    derived from the flower stalk of Agave americana waste (FSSAW), aiming to assess their suitability for bioenergy applications. Non-isothermal thermogravimetric analysis (TGA) was conducted at heating rates of 30, 40, and 50 °C/min. Kinetic modeling using the Coats – Redfern method evaluated 36 solid-state reaction models to determine the activation energy-Ea and pre-exponential factor (lnA). The highest Ea was observed for Model M22, increasing from 218.87 kJ/mol at 30 °C/min to 252.73 kJ/mol at 50 °C/min, while the lowest Ea, 4.22 kJ/mol, was recorded for Model M19. These results indicate the presence of both complex and simple reaction mechanisms, with a general increase in Ea at higher heating rates, consistent with the kinetic compensation effect. Thermodynamic analysis revealed a maximum enthalpy change (ΔH) of 249.65 kJ/mol, a maximum Gibbs free energy change (ΔG) of 390.81 kJ/mol, and a minimum entropy change (ΔS) of −0.31 kJ/mol·K, confirming that the pyrolysis process is endothermic and non-spontaneous, leading to a more ordered transition state. Criado’s master plot technique further validated Model M16 (random nucleation and growth) as the most representative mechanism during early decomposition stages. However, deviations at higher conversions suggest the occurrence of multi-step processes, including diffusion and char formation.
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    Unraveling the Pyrolysis mechanisms of Syagrus palm waste fibers through Gaussian deconvolution and kinetic modeling
    (Journal of Natural Fibers, 2025-09-22) Ferfari, Oussama; Belaadi, Ahmed; Alshahranib, Hassan; Ghernaout, Djamel; Mukalazi, Herbert
    The thermal decomposition kinetics and thermodynamics of Syagrus romanzoffiana waste rachis fibers (SrWRFs) were investigated through thermogravimetric analysis in a nitrogen atmosphere at heating rates (β) of 30, 40, and 50°C/min. The Coats–Redfern method was employed to determine kinetic parameters, including activation energy (Ea), pre-exponential factor (A), and reaction mechanisms. In contrast, thermodynamic properties such as enthalpy change (ΔH), Gibbs free energy (ΔG), and entropy change (ΔS) have been derived to evaluate the energy requirements and spontaneity of the pyrolysis process. A three-parallel Gaussian reaction model was employed to deconvolute the degradation profiles of hemicellulose, cellulose, and lignin, revealing distinct temperature intervals for each component: hemicellulose (200–345°C), cellulose (305–398°C), and lignin (220–650°C), with high fitting accuracy (R2 ≥ 0.99537). The kinetic analysis identified sigmoidal rate (SR) models (SR6, SR7, and SR8) as the most suitable, yielding Ea values ranging from 97.31 to 262.11 kJ/mol, which increased with higher heating rates. Thermodynamic results indicate that SrWRF pyrolysis is endothermic (ΔH > 0) and nonspontaneous (ΔG > 0), with negative entropy changes (ΔS) suggesting an increase in molecular order among the degradation products. The kinetic compensation effect was confirmed, demonstrating a linear relationship between lnA and Eₐ.