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/ϵ + 61.44/ϵ²)

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

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

where ϵ, 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%.

Keywords:

• carbonization
• char yield
• lignocellulosic material
• porosity

Acknowledgements

The work described here was supported by the CPER-DOCUP 2000-2006 of Région Guadeloupe-Project no. 23003. The authors are grateful to Mrs. Josely Lacroix for helping them, with improving the English language in this article.