Pre-design Optimization of Crude Oil Distillation Flowsheet

Several first principle models of crude oil distillation units were developed in Aspen PlusTM for purposes of pre-design optimization of flowsheet structure and apparatus design and choice of the optimal variant of distillation to provide the process flexibility in respect to flowrate of crude oil and oil quality. The developed models consider air temperature and type of crude oil. The two-column flowsheet of crude oil distillation is adopted as basic. The sum of the capital investments and operation costs per year was estimated for the basic flowsheet. Stepwise increasing of crude oil flowrate is used to determine “weak points” of the flowsheet and estimate maximum oil flowrate. Parametrical optimization was performed for each step. The alternative upgrading flowsheets were developed to increase operation effectiveness in a wide range of crude oil flowrates. The optimization criterion was developed to evaluate the relative efficiency of the alternative distillation unit flowsheets. The optimization criterion was a ratio of average annual revenue from the sale of petroleum products to the total costs (capital investments and operational costs) with restrictions on the product quality. The way of re-equipment of the column internals was chosen as a preferable variant.