MODELING, SIMULATION AND CONTROL OF CRUDE TOWERS

Crude towers are one of the most energy consuming, complex distillation columns in a refinery. A mathematical model for the rigorous dynamic simulation of a crude tower is presented. Because of the large dimension, large stiffness and non-linearity of the model, dynamic simulation of a crude tower has proven to be very difficult. In this paper, the Sum of Rates algorithm is shown to be suitable for obtaining the steady states of a crude tower. Once a steady state is approached, the dynamic responses of a crude tower can be simulated by the Bubble Point algorithm. The dynamic simulation predicts strong, one-way interaction among the product streams. Through dynamic simulation, it is shown that the interaction can be eliminated by a decoupler.