AN ENHANCED MILL extraction model has been developed to calculate mill performance
parameters and to predict the extraction performance of a milling unit. The model takes
into account the fibre suspended in juice streams and calculates filling ratio,
reabsorption factor, imbibition coefficient, and separation efficiency using more
complete definitions than those used in previous extraction models. A mass balance
model is used to determine the fibre, brix and moisture mass flows between milling
units so that a complete milling train, including the return stream from the juice screen,
is modelled. Model solutions are presented to determine the effect of different levels of
fibre in juice and efficiency of fibre separation in the juice screen on brix extraction.
The model provides more accurate results than earlier models leading to better
understanding and improvement of the milling process.