Improving mill efficiency through rapid analysis methodologies : final report 2014/051

Abstract

A rapid analysis system for measuring key constituents in sugarcane factory products has been developed using diode array (DA) near infrared (NIR) spectroscopic technology. Analysis of key constituents in prepared cane, bagasse, juice and syrup streams, magma, massecuite, molasses, raw sugar and mill mud is feasible. The benchtop NIR spectroscopic systems are mill laboratory-based and designed to augment the analysis already conducted by mill laboratories. More frequent analyses of mill factory products will allow Mill Engineers to minimise losses, and consequently, improve the factory’s coefficient of work. Additional benefits accrue through improved final product quality and the ability to schedule maintenance based on impurity loading.

The NIR spectroscopic analysis technique has been rigorously evaluated to demonstrate acceptable performance under different conditions. Validation of systems in green-field sites has shown that the global models provide suitable turn-key functionality. Standard error of prediction (SEP) values show that mature and semi-mature models are accurate against the traditional wet chemistry models and repeatability and reproducibility statistics for the NIR spectroscopic technique are better than those published for equivalent wet chemistry methods in the Australian and International method manuals.

Characterisation of selected sugarcane factory products highlighted the chemical and spectral variability in the samples, but molecularly-targeted calibration models did not improve the predictive performance of the NIR spectroscopic technique. Despite this, NIR spectroscopic models for the analysis of fresh raw sugar were developed and its demonstrated performance has been equivalent or better than the standard model for evaluating pol and moisture in fresh raw sugar.