Physico-combustion characteristics and suitability of six carbonized tropical hardwoods as biofuels for domestic and industrial applications

Carbonized wood quality varies, being influenced by their physical and combustion properties, which determine their suitability as biofuels. The physico-combustion properties of charcoals from six defect-free, regularly-used tropical timbers for carbonization (i.e., Anogeissus leiocarpa, Erythrophleum ivorense, Ficus sur, Berlinia occidentalis, Azadirachta indica and Vitellaria paradoxa) from Donkorkrom, Ghana, were studied. The timbers were randomly selected to avoid bias and the experiments setup in a Completely Randomized Design (CRD). The carbonized woods' qualities were ranked 1 (best) to 6 (worst) based on the cumulative average of their properties. Charcoal yield was greatest for E. ivorense (41.49 +/- 4.65%), and least for F. sur (22.26 +/- 4.71%). Moisture contents (MCs), densities, ash contents for the carbonized woods (i.e., 8%, 130 kg m(-3), <8% respectively) met the standards for trade on the International and European markets. E. ivorense charcoal recorded the greatest Water Resistance Capacity (96.333 +/- 0.57%), least burning rate (5.104 +/- 0.08 g min(-1)) and Specific Fuel Consumption (127.1443 +/- 4.867 g L-1). Their CVs (26939.24 +/- 105.91 J g(-1) for B. occidentalis to 29177.44 +/- 558.77 J g(-1) for A. leiocarpa) were also greater than the typical values (19400 J g(-1) to 20400 J g(-1)) by ISO. E. ivorense charcoal ranked best, while B. occidentalis and F. sur charcoals ranked worst. However, all the charcoals would perform well outdoors, suitably for domestic utilization (e.g. cooking and baking). In metallurgy, E. ivorense and A. leiocarpa carbonized woods would be most thermally-efficient.