Insights into the combustion behavior of cork and phloem: effect of chemical components and biomass morphology

Thermochemical analysis, wet-chemical analysis, and scanning electron microscopy observations were performed on granulated cork samples of Quercus cerris and Beaucarnea recurvata and on Q. cerris and Betula pendula phloems. The results show that the combustion behavior depends both on the chemical composition and the morphology of the bark fractions. The ignition temperature relies on the chemical composition while the combustion rate depends on the morphology and particle size. Ash and suberin contents are positively correlated with ignition and burnout temperatures of cork which vary between 255 and 290 °C, and 500 and 600 °C, respectively. Suberin delays the char oxidation reaction in cork. The average activation energies of cork and phloem are 31.1 and 21.2 kJ mol −1 in the first and second stages of combustion respectively.