Simple and inexpensive method of wood pellets macro-porosity measurement

A novel simplified stereometric measurement method for determining the macro-porosity of wood pellets through geometrical approach was successfully developed and tested. The irregular ends of pellets of circular cross-section were sanded flat so that their geometry becomes cylinder and their volumes evaluated using mensuration formula. Such formed cylindrical pellets were loose or tap filled to selected volumes to evaluate the macro-porosity and the constant specific weight. The method was extended to evaluate actual wood pellets properties. Overall macro-porosity of actual wood pellets was determined as 41.0 +/- 2.5% and 35.5 +/- 2.7%, mean bulk density as 670 +/- 29 kg m(-3) and 731 +/- 31 kg m(-3), and classified as Class-3:Medium and Class-3&4:Medium to Low for loose and tapped fills, respectively. Hausner ratio and Carr's compressibility index classify wood pellets as freely flowing. The developed stereometric method can be used as a handy inexpensive laboratory procedure to estimate the macro-porosity of different types and makes of wood pellets and other similar packaged materials. Published by Elsevier Ltd.