Abstract:
The solvent dehydration operation in azeotropic rectification tower of pure terephthalic acid (PTA) unit was simulated using Aspen Plus software where the activity coefficients in liquid phase were calculated by UNIQUAC model and the fugacity coefficients by Hayden-O'Connell one. The simulation results were consistent with the field data. Based on the simulation, a dynamic model using Aspen Dynamic was thus obtained. The influence of change in feed components on the solvent dehydtration operation was analyzed using HAc-H2O-NBA ternary phase diagram. Two controlling strategies (single-and bi-plate temperature controlling) for this column system were proposed to hold both bottom and top product specifications in spite of feed composition disturbances. The system dynamic responses of the two strategies to the change in feed components were tested by the dynamic simulation based on Aspen Dynamics. The better strategy was chosen to guid the industrial operation.