lignin on pellet durability.
Therefore, the increase of the percentage of pruning in the 2 PH
pellet blends allows to obtain a maximum value of durability of
96.2% for 75PR25 PH blend that which it is the only one that ex-
ceeds the value required by the International Standard of pellet
class quality B.
The 3 PH pellet blends, instead, hold the highest values of
durability never less 96.8% because of 3 PH pomace have a little
content of oil (4.4%) and also a lower lignin percentage than 2 PH.
Also the particle distribution in the raw material influences the
mechanical durability of the pellet blends; as we have seen, 3 PH
pomace presents a larger concentration of fine particles than 2 PH
and pruning and this fact increases the corresponding pellet
durability.