Co-Pyrolysis of Peanut Shells and Tea Plant Branches: Physicochemical Properties, Synergistic Effect and Thermo-Kinetic Analyses

Co-pyrolysis behaviors of peanut shells (PS) and tea plant branches (TPB) were explored with a focus on the physicochemical properties, thermal degradation behavior, synergistic effect, and thermo-kinetic analyses. The differences between individual biomass and the equivalent blend were also highlighted. Results showed that the blend sample showed an enhancement in fixed carbon content but a reduction in moisture and ash contents, when compared to those of the individual PS. The average activation energies (Ea) of the equivalent blend estimated by three isoconversional methods (i.e., Friedman, KAS, and Starink methods) were 181.65, 166.87, and 167.14 kJ/mol, respectively. The average Ea and ΔH of the blend were quite lower than those of the TPB but slightly higher than those of the PS. During pyrolysis, ΔH and ΔG exhibited positive values which showed the decomposition was endothermic and non-spontaneous. Negative ΔS values were first observed, followed by positive ΔS values at late conversion stage.