In this study, the influence of processing and
storage parameters on the strength of oil palm kernel shell
pellets was determined. The strength of the pellets
increased with compaction pressure but pelletizing pressures
above 188 MPa had little effect on the pellet strength.
At these high pressures, the pellets achieved no or nearzero
porosities, indicating that the maximum strength was
achieved. The diametrical tensile strengths of the pellets
were much weaker than the compressive strengths when
compacted at the same compaction pressure. The pellet
strengths were found to increase with longer hold times
during the compaction process. This was due to a continuous
decrease in porosities until near-zero porosities were
achieved, when increasing the hold time no longer led to
further strengthening of the pellets. The time-dependent
characteristic of the pellet strength was also reflected in the
reduction in strength as compaction speed was increased.
The strength of the pellets decreased significantly after
1 day (24 h) of storage, with a higher decrease observed
when the pellets were stored under a higher humidity
condition. These changes during storage could create difficulties
during handling and transportation and may affect
gasification performance.