Comparative study of torrefaction of empty fruit bunches and palm kernel shell

Abstract

This paper describes the effect of torrefaction on the characteristics of empty fruit bunches (EFB) and palm kernel shell (PKS). The torrefaction of EFB and PKS was investigated in a horizontal tubular reactor at a temperature ranging from 150 to 600 °C, for torrefaction residence time varying from 0 to 50 min. The torrefied products were characterized in terms of their elemental composition, energy yield, ash content and volatile fraction. The present study developed the torrefaction kinetics of EFB and PKS in a thermogravimetric analyzer to obtain the kinetic parameters. EFB and PKS exhibited excellent energy yield values. The gaseous products from torrefaction of EFB and PKS were also analyzed. Furthermore, the study reveals that the carbon content increases with an increasing torrefaction temperature but the O/C ratio, hydrogen and oxygen content decrease for both EFB and PKS. The energy yield and mass yield were found to decrease with an increase in the torrefaction temperature while the higher heating value (HHV) increased. From this study, torrefaction temperature between 290 and 320 °C is the optimum torrefaction temperature for EFB while torrefaction temperature between 300 and 320 °C is the optimum torrefaction temperature for PKS.