Experimental assessment of the energy potential of pellets produced from beekeeping wastes by updraft gasification

This research experimentally evaluates the gasification of slumgum, a beekeeping waste, to test its potential as a fuel. It provides novel insights as the first experimental study on slumgum for energy purposes. First, pellets were produced with slumgum and mixtures of slumgum and pine sawdust, undergoing ISO 17225 standard tests. Subsequently, the gasification of the pellets was performed in a modified updraft gasifier, in which the temperature inside the reactor and the composition and lower heating value (LHV) of the producer gas were measured. The slumgum pellets stood out for their high mechanical durability and higher heating value (HHV), with respective values of 99.98 % and 27.66 MJ/kg, possibly due to their high-fat content (40.25 %). Negative aspects are the high sulfur (2.17 %) and nitrogen (3.52 %) content, which prevents the slumgum pellets from qualifying within ISO 17225-2 or ISO 17225-6 standards. Gasification results showed improved LHV with increased sawdust content, reaching 7.62 MJ/Nm3 for a 50 % slumgum and 50 % sawdust pellet. The equivalence ratio "ER" remained in the range of 0.0125 to 0.0204, which is too low compared to typical ER values reported in the literature. It was not possible to increase the ER value, since an increase in air flow resulted in an increase in the fuel consumption rate. Despite challenges, this study highlights slumgum's potential as a supplementary biomass fuel.