Modelling the extraction processes of milling trains

Australian sugar factories have made limited use of a milling train extraction model developed at The University of Queensland about 30 years ago. In recent years, the Sugar Research Institute (SRI) made modifications to that model in an effort to make the performance indicators in the model more relevant to factory engineers. This has been achieved by replacing the performance indicator known as the imbibition coefficient with two other performance indicators, 'crushing factor' and 'mixing efficiency'. The crushing factor describes the preparation that occurs in a milling unit while the mixing efficiency describes how well the imbibition mixes with the feed bagasse to a milling unit. This paper describes the current model and the differences between the original model and the current model. It describes the ways in which the model is intended to be used and the information required before the model will fulfil its potential. In summary, the extraction model can be used for the analysis of performance of an existing milling train or the prediction of the performance of a milling train as a result in a change to the milling plant. The model in its current form can be used to analyse the performance of an existing milling train by calculating the performance indicators. However, its use in predicting the performance of a milling train is limited because the factors affecting the new performance indicators are not known.