Determination of calorific values of forest waste biomass by static bomb calorimetry

Calorific values of forest waste originating from forestry works such as woodland cleaning, reaforestation and, all other silviculture tasks, were measured by static bomb calorimetry. These waste materials, heretofore considered as useless refuse, are beginning to be used as alternative fuels in wide social sectors all over the world. Two of the main forest species, eucalyptus (E. globulus Labill) and pine (P. pinaster Aiton) existing in Galicia (NW Spain), are included in this study. The experimental procedure was based on that proposed by Hubbard et al. [Experimental Thermochemistry, Interscience, New York, 1956, p. 5]. Simultaneously, some other parameters such as elementary chemical composition and heavy metal contents, moisture, density, and ash percentage after combustion in the bomb, were also determined. The experimental results, with calorific values exceeding 20 000 kJ kg−1, make it advisable to use these materials as alternative fuels. The different parameters were measured using, as main equipment, a bomb calorimeter with an oxygen atmosphere, an elementary analysis equipment, and an atomic absorption spectrophotometer.