A GENERALIZED DYNAMIC MODEL FOR DISTILLATION COLUMNS-III. STUDY OF STARTUP OPERATIONS

Abstract-The dynamic behavior of distillation columns during startup operations have been studied and analyzed. A procedure is proposed for determining appropriate startup policies for distillation column operations based on the analysis of the dynamic behavior. The final startup policy consists of three strategies corresponding to the three characteristic stages of the startup operation. The proposed procedure has been successfully applied to a test problem. Numerical results of the dynamic behaviour and the test problem are presented. Scope--Startup operations of chemical processes and in particular, distillation columns, represent interesting problems in operability, control and simulation. Most research efforts on startup operations of distillation columns in the past have concentrated on actual plant experiences [I-3]. These papers have mainly described the problems related to plate hydraulics during the early stages of the startup period and operability problems. A good understanding of the dynamic behavior is necessary for the development of appropriate startup policies. Procedures by which these policies can bc deteimined could serve as useful tools both for the operators and designers of plants. For the operators, the information would prepare them better to diagnose and handle many possible operational problems and also give them a knowledge of the effect