Epsilon Archive for Student Projects

Abstract

There is a need for productivities data and data for different types of machines for comminution of logging residues. The lack of data and studies on GROT comminution makes it difficult to evaluate different chains for handling of residue fuels and make system analyses.

Four types of machines with three different working principles were compared at six studies during winter conditions. Three to eleven trials during 9.5 to 30.7 minutes were made on each machine. Samples from the produced material at each study were sieved to determine the size distribution of the comminuted material. Samples were also taken from the studies for determination of moisture content. The production per time unit (ton/h) was measured and how much of the time that the machine was working effectively. The number of crane cycles that were used for feeding the machine was also counted.

The machines produced between 55 and 168 MWh / h. The cost for comminution was calculated for each machine and it ranged between 14.4 and 17.8 SEK/MWh except one case reaching 25 SEK/MWh. Size distribution of comminuted material showed no significant difference between the machines. The analysis of effective working time by the operating time the team around the Willibald 4800 machine was remarkable by having only 20% idle time. The performance around the Willibald 4800 machine was also remarkable by having the least number of crane cycles per minute to feed the machine.