Implementation plans for supervisory control of pan stage operations

Pan stage operations have a major influence on the quality of shipment sugar production, the processing efficiency of the centrifugal and dryer stations, the sugar recovery from final molasses and the steam consumption of raw sugar factories. As well, for many factories, the production capacity of the pan stage is often the rate limiting station of the factory. Several Australian factories now operate with only one pan stage operator and a management tool such as a smart supervisory control system (SSCS) would assist the operator in making better decisions for managing the stage. The SSCS integrates the projected boil-on rates for syrup and molasses to each pan on the stage with the forecast production of syrup based on cane receival data and molasses from the centrifugals. By using the phase of each pan into an operational model the levels of syrup, A molasses and B molasses in the respective stock tanks are forecast and the information used to forewarn of potential problems or inefficiencies if current operating strategies are maintained. A hybrid fuzzy logic based expert system is employed to advise corrective procedures. While the system is not yet adopted commercially each phase of the development plan has been undertaken. Forecast tank levels have been found to compare favourably with actual tank levels. The SSCS should result in improved use of the installed equipment on the pan stage to achieve increased sugar recovery, improved sugar quality and reduced steam consumption while fulfilling the production rate requirements. One of the important benefits of the control system should be reduced variability in the steam consumption on the pan stage, leading to improved steam economy for the factory.