Effect of particle size and heating rate on pyrolysis kinetics of Nerium oleander

Nerium oleander is a lignocellulosic biomass which is not consumed by cattle due to its poisonous nature. The effect of two important parameters namely particle size and heating rate on thermal degradation profiles of leaves and stems of N. oleander under pyrolytic conditions were studied using thermogravimetric analysis (TGA). Experiments were conducted using heating rates from 5 to 20 degrees C min(-1) in the pyrolysis temperature range of 0-1200 degrees C under 100 sccm nitrogen flow. Three different particle sizes 125, 500, and 1000 mu were considered for this study. Three degradation stages (each for hemicellulose, cellulose, and lignin) excluding the moisture loss were found for the chosen biomasses irrespective of particle size and heating rate. The kinetic rate parameters for hemicellulose, cellulose, and lignin were found using mass loss data obtained from TGA assuming first order kinetics using Coats-Redfern model. The assumed first order kinetics was proved correct for all the biomasses chosen based on the R-2 value for the experimental data. Lower range of activation energy for hemicellulose and cellulose was observed for all particle sizes at lower heating rate when compared with lignin for both leaves and stems of N. oleander.