Developing an Empirical Formula for the Assessment of the Char Yield of Pyrolyzed Lignocellulosic Materials

Abstract

A new empirical formula, based on 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 pyrolyzed in a 600°C–900°C temperature range. The following equation is proposed:

Y (wt%) = (0.8815 ? 2.281/? + 61.44/?²)

· {L(0.59 ? 2.74 × 10^?4 (t°C ? 600) + 0.22C]

+ A ? 0.1 E 1 + 2 × 10^?3 (600 ? t°C)]}

where ?, L, C, A, and E are parameters of the precursor, namely: 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%.