Development of a method for determining the charcoal calorific value variability as integration of the UNI EN ISO 18125:2018 standard

The charcoal is a fuel widely used since ancient times in many Countries with very different applications. On the market it is possible to find material from different Countries that use various wood species and production processes. The determination of the qualitative characteristics of charcoal is carried out following what is reported in the UNI EN ISO 17225-1:2014 standard. For energy purposes, the determination of the calorific value has a primary importance. Proceeding as indicated by the UNI EN ISO 18125:2018 standard, which provides the grinding of the sample before being analyzed, homogeneous and repeatable values are obtained. However, the use of this method does not reflect the great variability of the calorific value present within the same sample which can also be of the order of 7 MJ/kg. To this purpose, a new analysis method has been proposed to be combined with what is indicated in the standard. The new method uses the samples as they are to determine the real properties of the material and its internal variability. To make the value obtained during the analysis more representative of the differences in calorific value into the sample, it is appropriate to correlate the range of variation obtained in the calorific value to the average value, determined according to the standard.