Textural analysis for better correlation of the char yield of pyrolysed lignocellulosic materials

A new empirical formula, based on the surface fractal dimension, the porosity, the botanical composition and the ash content of the precursor is proposed for the assessment of the char yield, Y (wt %) of lignocellulosic materials pyrolysed in a 600–900 °C temperature range. The following equation is proposed:Y(wt%)=Dflnɛ[L[0.59−2.74×10−4(t°C−600)]+0.22C+A−0.1E[1+2×10−3(600−t°C)]]where Df, ɛ, L, C, A and E are parameters of the precursor, namely: fractal dimension, porosity (%) and percentage (wt%) of lignin, cellulose, ash and extractives, the t temperature, being in the Celsius grade.The values calculated by the formula fit satisfactorily with the experimental results, the gap being less than 0.5%.