Sieving of chipped forest fuels has recently been suggested as a way to reduce dry matter losses during storage. Sieving provides a more homogeneous acceptable material with better storage properties, which reduces the risk of energy and dry matter losses and spontaneous ignition.

Screened chips can be priced higher due to better quality, and both acceptable and reject fractions are more homogeneous, which improves combustion control. Sieving is costly and the reject fraction is not suitable for storage. Five sieving operations were studied, three involving vibrating screens and two involving star-screens.

On average, star-screens were more productive than vibrating screens. In all operations, the sieving machine limited productivity, and the loader feeding the machine was not fully utilized. Sieving costs were under two euro per MWh of chips, which may be recovered through higher values and lower storage losses in the acceptable fraction.

If sieving operations were used to increase storage of chips, it could increase the annual utilization of chippers and chip trucks in the supply chain, thereby reducing supply costs. Profitable sieving operations require demand for the fine fraction at a price close to that of residue chips.

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And as part of the eagerly awaited Wood Residues 2022 event running in Rotorua, New Zealand on 26-27 July 2022, two leading companies in biomass or wood residues extraction and handling, SHL Forest & Wood Fibre Solutions and Canterbury Woodchip Supplies will complimenting the earlier workshop that’s running on in-field chipping systems with practical lessons from their own in-field chipping operations in the North and South Islands of New Zealand.

Full details on the programme along with registration details can be found on the event website.