Page 60 - FDMAsia SepOct 2024

58 MATERIALS SEP/OCT 2024 FDM ASIA | www.fdmasia.com

the generally known shortcomings which often occur when produced from beech were also those with the highest age
producing pellet from broadleaves species, among the investigated ones. This aspect had for sure an
in terms of high ash content, low heating value, and low influence on the positive performance of beech pellets.
bulk density. However, we found that increasing the stem However, it is also true that forest management in beech

age is beneficial for ash content, suggesting that material forests in the Mediterranean context consists mainly in
retrievable from thinning in high forests could be a better conversion from coppice to high forests or in thinning in
feedstock than material from coppice. high forests. Thus, the logged stands always have an age of
We further showed that beech pellets demonstrate promising higher than 30 years, and our samples were representative
results concerning bulk density and ash content, and that the of the beech wood which could be retrieved and used for
shortcomings related to low heating value could be addressed pellet production in the study context.
by blending with turkey oak biomass.
This blend can compensate for the characteristics of turkey Future Investigation
oak biomass as it was satisfactory only for the heating value. To assess the pellets’ quality in comparison to the mandated

Thus, we recommend that future trials in the topic should standards, we used a novel statistical technique.
investigate quality of pellets produced by blending beech We recommend the application of this approach in the
and oak in the framework of small-scale pellet production. field of biomass quality evaluation given that it has exhibited
Among the possible limitations of our study, it is possible efficiency, and it is simple to interpret. This approach can be
to mention that this was a preliminary trial, based on a limited recommended for further application in the sector of biomass
number of species and focused on pellet produced with quality evaluation to compare different pellet types.
small-scale machinery. We also validated the well-known drawbacks that frequently

Future studies should involve more species and more arise when pelleting broadleaf species, which are associated
management systems in order to develop models which are with a high ash content, low heating value, and low bulk density.
even more reliable. Furthermore, modelling the influence of We discovered that raising the stem age improves the ash
bark percentage on pellet quality can represent an interesting content. This suggests that material which has been recovered
research topic. through thinning in high forests might provide a better feedstock
Most importantly, we obtained promising results concerning than material from shorter rotation management systems.
beech pellets, but it is important to highlight that the pellets Additionally, we demonstrated that beech pellets had
encouraging results in terms of bulk density and ash content.
Media Raw Stock We suggest that the poor heating value of the beech pellets

could be addressed by combining them with turkey oak
biomass, which instead only showed a good heating value.
Furthermore, using the wooden materials retrieved from
thinning in older stands can provide pellets with higher quality.
Therefore, future studies on the subject of small-scale
pellet manufacturing in the Mediterranean region should
focus on investigating the effects of blending among different

broadleaved species on the final pellets’ quality. FDM
ENQUIRY NO. 5301