DYNAMIC SIMULATION AND NONLINEAR-MODEL-BASED PRODUCT QUALITY-CONTROL OF A CRUDE TOWER

The dynamic stagewise adiabatic flash algorithm is applied to the dyna mic simulation of a crude column. This algorithm is based on the impli cit integration of the model equations of each stage and the explicit combination of the stage models to form the column model. Stable, effi cient integration for the crude column model is observed with simulati on CPU requirements that are 20 times faster than real time using a 50 MHz 486 P.C. Specific dynamics of a crude column are identified such as one-way interaction and inverse action. The dynamic crude column mo del is used to study product quality control of a crude column using n onlinear-process-model-based control (PMBC) which was tested using two different steady-state controller models for setpoint tracking and di sturbance rejection. Both nonlinear PMBC controllers show good control performance, but are limited by the inherent inverse action of the cr ude column. Control results for a set of single-loop PI controllers is also presented as a point of reference.