in the scheduling of oil transfer operations for harbor plants containing ships, piers, tanks and pipelines, an optimization model is frequently used. however, due to the complexity involved, computational time is a real concern. in this paper, a mixed integer linear programming model (milp) found in the literature is studied and a preprocessing procedure is proposed. this procedure is based on the theory of constraints (toc), which is used to reduce the model compilation time. since the problem bottleneck is identified, the corresponding constraints are not considered in the preprocessing step. an analysis based on lp dual price is also carried out to verify actions taken in the preprocessing step. although optimality cannot be assured, the results obtained show a minor deviation from the optimal solution but with a significant computational time gain.