Comparative study of local Tunisian woods properties and the respective qualities of their charcoals produced by a new industrial eco-friendly carbonization process

In order to evaluate their potential to be used as charcoal production by a new industrial thermal treatment process; the wood of seven trees of introduced species in the North eastern Tunisia (3 Eucalyptus, 4 Casuarina) and 1 local species (Tetraclinis) were selected. Physical properties of natural woods and Gravimetric yields in charcoal, ultimate composition, heating values measurements and combustion quality tests were performed before and after carbonization process. For the same thermal degradation intensity (550 °C—4 h), Gravimetric yields in charcoal values were comprised between 41.1 and 45.3.9% for Casuarina wood species, 35.5 and 39.4% for Eucalyptus wood species and was 33.7% for Tetraclinis articulata wood. Elemental composition showed a significant difference between the selected species. It varies from 1.46 to 1.65 for H/C and 0.67 to 0.77 for O/C. Casuarina wood species showed the lowest values for the both ratios. The calorific values showed that the selected wood species have Heating Values ranged from 16.264to 20.798 MJ/kg and allow producing charcoal with heating values comprised between 23.871 and 30.943 MJ/kg. The best energetic improvement by carbonization process, in this work, concerns Eucalyptus and Tetraclinis woods, except for the Eucalyptus salmonophloia but the combustion quality showed that Casuarina wood species appears to be the wood species with the most optimal combustion, after undergoing a carbonization process. (Résumé d'auteur