SYRUP CLARIFICATION FOR PLANTATION WHITE SUGAR TO MEET NEW QUALITY STANDARDS

摘要

There is significant interest in many sugar producing countries towards producing a higher quality plantation white or direct consumption sugar with lower colour and lower residual sulfur dioxide levels. National standards for residual sulfur dioxide and colour have been lowered to reflect the growing demand for improved quality and concerns for health risks. Investigations at SRI have focused on identifying optimum conditions for clarification options to remove scale components, colour and other impurities by clarifying intermediate and final effect syrups. Trials in two Australian factories demonstrated the benefits for improved sugar quality and productivity improvements for the pan and centrifugal stages. Recent investigations in four overseas countries have focused on the application of syrup clarification with or without syrup sulfitation to achieve compliance with the changing standards. Results show that syrup clarification technology can be used to achieve lower sugar colours and reduced residual sulfur dioxide. In one case where syrup clarification was used in conjunction with syrup sulfitation, the colour of the product sugar was reduced from about 150 IU to below 100 IU. In another case, the colour of the sugar was reduced from 150 IU down to 120 IU by replacing the syrup sulfitation process with syrup clarification. In the latter case, residual sulfur dioxide values were reduced from about 25 ppm down to about 14 ppm. There are other advantages to be derived from clarification of the raw syrup, including reduced turbidity and lower ash. A reduction in viscosity has provided productivity gains for the pan and centrifugal stations.