Sugarcane Bagasse - Estimated Losses Before the Digester
By Robert W. Hurter, P. Eng., MBA, President, HurterConsult Incorporated, May 2001

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When properly cleaned and prepared nonwood fibre raw material enters the digester, many of the hurdles of producing pulp and paper from nonwoods have been overcome.
In many instances, however, economic problems encountered by nonwood-based pulp and paper mills are related to a lack of attention to the losses which are incurred before the digester. Losses from the field to the digester have a significant impact on the amount of the nonwood fibre raw material required and the cost of the fibre raw material per ton of pulp produced.
These losses generally can be classified as:
 transportation and storage losses
 fibre preparation losses which depend on the type of nonwood raw material being processed and the selected fibre preparation system.
Once it has been determined how much prepared raw material is needed to feed the digester, the next step is to develop a clear understanding of the transportation, storage and fiber preparation losses, all of which are critical to establishing how much nonwood fibre raw material must be harvested and delivered to the mill. Please refer to Fibre Raw Material Issues are Critical to the Success of Nonwood Pulp & Paper Mills for additional details.
The following figures provide some general rules-of-thumb concerning losses before the digester for sugarcane bagasse and the selected fiber preparation systems. The amount of loses for a given raw material can change significantly depending on the configuration of the selected fiber preparation system. For example, adding wet cleaning before or after moist depithing will reduce the amount of residual sugars contained in the depithed bagasse sent to storage. This will reduce the amount of fiber degradation in the storage pile but does increase the preparation losses.
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