Sunflower shells utilization for energetic purposes in an integrated approach of energy crops: Laboratory study pyrolysis and kinetics

Sunflower is a traditional crop which can be used for the production of bioenergy and liquid biofuels. A study of the pyrolytic behaviour of sunflower residues at temperatures from 300 to 600 C has been carried out. The experiments were performed in a captive sample reactor under atmospheric pressure and helium as sweeping gas. The yields of the derived pyrolysis products were determined in relation to temperature, with constant sweeping gas flow of 50 cm3 min 1 and heating rate of 40 C s 1. The maximum gas yield of around 53 wt.% was obtained at 500 C, whereas maximum oil yield of about 21 wt.% was obtained at 400 C. A simple first order kinetic model has been applied for the devolatilization of biomass. Kinetic constants have been estimated: E = 78.15 kJ mol 1; k0 = 1.03 · 103 s 1.