Preparation and characterization of pyrolytic chars from different biomass samples

In the present work four different biomass samples (pine cone, soybean cake, corn stalk and peanut shell) were pyrolyzed to 550 °C in an inert gas atmosphere and a comparison between the properties of chars produced has been performed. Characterization of biomass samples was carried out with FT-IR, 13C NMR, SEM and EDX. The influence of the parent material on char quality was investigated. The chars were characterized by their proximate and ultimate analysis and surface areas by N2 adsorption at 77 K using BET equation. The morphological changes in carbonaceous solids were observed by scanning electron microscopy (SEM), and FT-IR spectra were obtained to evaluate the functional groups. The results obtained from the different techniques were combined to give an overview of the chemical and physical properties of the biomass char samples.

► Four different biomass samples were characterized using elemental analysis, FTIR, SEM, EDX and 13C NMR.
► Fixed-bed pyrolysis experiments at 550 °C gave char yields in the range of 25–30% for biomasses.
► Surface areas were relatively higher for the chars obtained from pine cone and peanut shells mainly due to their high lignin content.
► Soybean cake and corn stalks gave quite lower surface areas indicating that their direct utilization as activated carbons is unfeasible.