Optimal Integrated Operation of a Sugar Production Plant

In this work an integrated approach to the operation of the evaporation and crystallization sections of a sugar refinery is proposed. The objective is the minimization of the fresh steam consumption and of its variance, while several process constraints must be satisfied. The employed model is taken from the sugar plant benchmark of the EU Network of Excellence HYCON2-Highly-Complex and Networked Control Systems. A dynamic optimization problem is formulated for computation of optimal trajectories of the manipulated variables. Significant savings in the amount of steam consumed in comparison to the traditional operation were obtained for one cycle time. In order to keep the levels in the buffer tanks (connecting the continuous and discontinuous sections of the plant) within safe values, a hierarchical coordination structure based on a temporal decomposition of the problem is implemented, which ensures a continuous and safe operation in the long term.