Pyrolytic conversion of halophyte (Tetraena coccinea)

Abstract Pyrolytic conversion of Tetraena coccinea, a halophilic plant widely found along the coastal belt of the Saudi Arabian Red Sea, was investigated for its bio-energy potential. The kinetic triplets of pyrolysis were estimated from model-free and model-fitting methods using the conversion data obtained under non-isothermal conditions. Activation energies estimated from model-free methods such as Friedman, Flynn-Wall-Ozawa (FWO), and Vyazovkin methods were 96.40 (±14.98), 84.50 (±13.89), and 65.32 (±12.38) kJ/mol, respectively. Combined kinetics and master-plot considering a single-step reaction indicated third (F3) or fourth order (F4) reaction as the most probable mechanism. The differential thermogravimetric profile indicated complex conversion in the active pyrolysis zone. Two subzones in the active pyrolysis region were investigated using the Coats-Redfern method. From 20-55% conversion, F4 or diffusion 3-D (D3) reaction were the most probable mechanisms, whereas, during 55-80%, the probability of the F4 reaction mechanism was the most likely. ΔH, ΔG, and ΔS indicated that the conversion process was endothermic and non-spontaneous throughout the conversion range.