Study on the thermal behavior of different date palm residues: Characterization and devolatilization kinetics under inert and oxidative atmospheres

Date palm residues are an attractive source of biomass energy since they are renewable, abundantly available and do not compete with food crops. Pyrolysis and combustion may be efficient methods of exploiting energy from these biomass resources. The purpose of this research was to investigate the thermal behavior of date palm biomass in order to evaluate their usefulness for energy production. In fact, ultimate and proximate analyses as well as thermal behavior of different date palm residues (date palm leaflets (DPL), date palm rachis (DPR), date palm trunk (DPT), date stones (DS) and fruitstalk prunings (FP)) were investigated. Non-isothermal thermogravimetric analyses (TGA) were performed to assess fuel reactivities under inert and oxidative atmospheres. Thermal degradation of all samples has exhibited quite similar behavior except DS. In contrast, different properties (e.g., reactivity, HHV or activation energy) were obtained, which may be attributed to a difference between tree parts composition (branches, trunk, fruit…). Thus, DPT and FP were found to be the most reactive materials in inert conditions; while in oxidative conditions, DPR is the highest one. In addition, activation energies corresponding to devolatilization regions under inert and oxidative conditions were 49.8, 45.2, 52.7, 50.9, 89.1 kJ mol−1 and 58.9, 49.6, 67.6, 57.7, 110.7 kJ mol−1 for DPL, DPR, DPT, DS and FP respectively. The obtained data, sample properties along with thermal behavior under inert and oxidative atmospheres as well as kinetic parameters, allowed the comparison of the obtained results with other biofuels and can be useful for the design of processing system for energy productions.