Several chemicals are produced from brines by solar crystallization using solar ponds.The process of salt harvest consists on mechanically retiring the salts precipitated in thesolar evaporation ponds and to leave them in its respective stockpile. In an industrialoperation several ponds are used for the fractional crystallization of several salts, andtherefore the harvest planning can be a nontrivial task. Therefore, the objective of thiswork is to plan the feeding flow to each of the solar ponds, the manipulation of solution,and the solutions and solids inventories in each pond that maximizes the production andthe harvest periods. All this having as input data the evaporation rate, concentrationrange of the feeding, concentration range for the pond, and the operational initialconditions. The model developed corresponds to a MINLP, which includes the massbalances in each pond, equilibrium conditions, and planning & operational restrictions.The problem was solved in two steps, first the maximization of the salt harvest wasdetermined and then, using this maximum harvest, the maximum availability of thecontractor was determined. Several cases have been studied, including: ternary (NaNO3-KNO3-H2O) and quaternary systems (KCl-KNO3-K2SO4-H2O), pond systems with 3and 4 ponds and with different areas, and considering 12 and 26 operation periods peryear.
展开▼
