SOME INTERESTING BEHAVIOURS OF PREPARED CANE AND FINAL BAGASSE

THERE ARE OPPORTUNITIES to decrease bagasse moisture from a milling unit, with substantial financial benefits, for example, from co-generation. Also, there has been some recent renewed interest in the valuing of the contents of bagasse and the assessment of the milling performance of new cane varieties. Previous laboratory investigations have shown that juice flow through prepared cane and bagasse obeys Darcy’s permeability law, that the grip of the rough surface of the grooves on the bagasse can be represented by the Mohr-Coulomb failure criterion for soils, and that the internal mechanical behaviour of the bagasse is critical state behaviour similar to that for sand and clay. However, the extension from this laboratory fundamental work in order to describe and improve the design and operation of factory units remains unrealised. This paper presents some interesting behaviours of prepared cane, first bagasse, and final bagasse that have mostly been previously unreported, with a focus in change in volume of the materials under changes in stress, the resulting reduction or increase in juice pressure and its potential effects on the removal of juice. Details of the experimental geometry and procedure are presented which are relevant to the drainage and grip requirements of mill rollers. With reference to the same equipment, the last part of the paper links the testing of cane varieties to provide a unified story of compaction and feeding behaviour in a milling unit.