THE APPLICATION OF NETWORK NIR CALIBRATION EQUATIONS AT THE MARYBOROUGH SUGAR FACTORY

THE work described in this paper includes the installation, commissioning and validation to successful performance of a FOSS Cane Analysis System (CAS) at the Maryborough Sugar Factory in 2003. It is noted that the system equations loaded contained no data from the Maryborough region or the NIR spectrophotometer used in the CAS. The results demonstrate that the transfer of FOSS based calibrations can be achieved with no loss in analytical performance. The system was implemented at the Maryborough Sugar Factory to address cane quality issues, high processing costs, provide outputs for improved factory control and determine the effects to millers and growers of using the CAS for direct determination of CCS for payment purposes. The system library required the addition of 350 valid spectra collected over roughly one week to adequately represent the new instrument and cane supply. Constituent biases were calculated and applied after the first week of operation and were the only adjustments made to the system. The precision of the CAS results was found to be within expected limits for all constituents except brix in cane and fibre; the reasons for the higher than expected error for these constituents are still under investigation. The bias for all constituents was demonstrated to have a diurnal cycle and long-term drift. This effect was found to be due to variation in cane temperature and adjustment based on this parameter resolved the problem for all constituents. The seasonal average for the current laboratory method for CCS was (15.12) using class fibre, and the CCS directly determined by NIR was (15.14), and as the reported errors were within expected system limits, there is no equity barrier to the implementation of direct NIR CCS in cane payment for the 2004 crushing season. All stakeholders in the Maryborough cane-growing district agree in principle with this philosophy. The hurdle remaining is the difficulty in changing the cane payment formula to achieve a winwin scenario for all parties.