Doctor of Philosophy (PhD)


Engineering Science (Interdepartmental Program)

Document Type



Efficient crystallization in raw sugar production is the result of a combination of factors and responses that meet specific criteria. Matching a sugar quality standard, maximizing sugar yield, maximizing crystallization equipment capacity and minimizing heat requirement are all necessary optimization criteria. A double centrifugation or purge of C-magma is intended to improve raw sugar whole color by the reduction of color recirculation with the sugar crystal. Combining a three boiling crystallization scheme with a second centrifugation after the last crystallization stage required optimizing the input/output product parameters (purities) and the location of the liquid recycle component (double purge molasses) for efficient integration. Sugars™ and JMP® were software programs used to solve this multiple-response optimization problem using a multistage approach. The optimization strategy went from actual data correlations, experimental design, computer simulations and surrogate models to a desirability approach that transformed the problem from multiple-objective functions into a single objective function, the overall desirability. The implementation of the double purge system by three Louisiana sugar factories confirmed the reduction of whole color of raw sugar, up to 47%, and the linear relation between double purge magma purity and raw sugar whole color. An overall desirability expression was applied to find the optimal input/output product parameters of the double purge system for different scenarios using JMP® optimization algorithm. Optimal control parameters and recycle determined by this strategy matched the average settings used during actual operation at the 2013 sugarcane crop season. In addition, surrogate models were used to evaluate the importance of the random and control parameters for each response and for each syrup purity scenario. This optimization strategy offers an approach not only to evaluate the importance of several product parameters or the optimal settings, but also offers a better understanding for sugar factory processes and for troubleshooting specific undesired responses. In the future this optimization strategy may be applicable for integrating additional equipment and for improvements of existing process stages at any sugar facility



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Hall, Steven G.