DEVELOPMENT AND TESTING OF A SUGARCANE HARVESTER SINGLE DRUM CHOPPER SYSTEM

A GLOBAL push towards renewable energy has led to the construction of efficient cogeneration plants in Australian sugar mills. To maximise the amount of energy that can be generated from the crop, whole-crop harvesting has been introduced, to maximise the amount of total biomass sent to the mill. An adverse effect of whole-crop harvesting is a significant reduction in bulk density of the harvested material. Transport costs to harvester owners and millers significantly increase as bin weights are reduced, and therefore there is a case for developing a harvester chopper system which maintains bin weight as the amount of trash sent to the mill increases. A single drum chopper system was developed in this study and a prototype was constructed for experimental assessment of the performance of the system. Cane and juice losses and billet quality were measured for a range of operational conditions which included varying the chopper drum speed and material pour rate. The cutting process was captured by high speed photography for analysis into the causes of damage and losses. Speeding up the chopper drum and therefore shortening the billet length proved to have the most detrimental effect on system losses, with reducing the target billet length from 200 mm to 100 mm resulting in over three times the overall losses. An increase in pour rate did not have a significant effect on losses or billet quality. For the set of trial conditions most closely representing those previously achieved with differential choppers, the single drum system produced similar efficiency results. However, the advantages of this system are most prominent in whole-crop harvesting where shorter billets are required to maintain bin weights. Several modifications to the concept are suggested which are expected to significantly enhance the performance of the concept in future trials.