An Optimal Design of Crude Distillation Unit Part 1. Determination of Optimal Feed Tray Locations

As a crude distillation unit(CDU) is one of the important processes in refinery industries and consumes enormous energy, an optimal design of a CDU was attempted. The target CDU is under commercially operated and its capacity is 150,000 BPSD. The mathematical models for an atmospheric distillation column(ADC) and naphtha stabilizer were established and we formulated the objective function so as to minimize the energy consumption. The optimal feed locations of both the atmo- spheric distillation column and stabilizer were obtained by solving mixed-integer nonlinear programming problems. The opti- mal duties of condenser and pumparound in the ADC were determined by the optimization task. In the case of optimal design, vapor and liquid load was apparently decreased and the size of the ADC and the stabilizer was accordingly decreased. The opti- mal feed tray of ADC and stabilizer were 34 and 14 respectively, and the condenser duty of the ADC was decreased by the amount of 15% and the duty of pumparound, which permits heat recovery, was increased by the degree of 37%.