Effect of piece size and tree part on chipper performance.
Assirelli, A.; Civitarese, V.; Fanigliulo, R.; Pari, L.; Pochi, D.; Santangelo, E.; Spinelli, R.
Biomass and Bioenergy
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|Abstract in English:|
A commercial drum chipper was fed alternately and piecewise with poplar stems and
poplar tops, in order to determine the effect of piece size and tree part on machine performance.
Chipping stems required most of the available power (231 kW) delivered by the
tractor, whereas chipping tops took about half that much. However, productivity was twice
as high with stems, compared to tops (i.e. 25 and 11 t h1 of oven dry wood, respectively).
As a consequence, specific fuel consumption per unit product was 15% lower with stems,
compared to tops e i.e. 0.61 and 0.72 L m3, respectively. Mean feeding speed was
0.37 m s1 for stems and 0.41 m s1 for tops, but the difference was not significant
( p ¼ 0.1677). Productivity and fuel consumption were strongly related to piece size, but tree
part had its own additional effect, independent from size and possibly related to form.
When chipping tops it is advisable to feed more pieces at a time, in order to partly
compensate for the effect of piece size. Operators expecting to chip primarily small-size
materials may acquire special chipper versions with wider drums and additional side
rollers, for smoother mass feeding.