Model based control of semi batch polymerization reactors

The main objective in polymerization processes is to produce polymer within the desired characteristics. Due to polymerization reactions are highly exothermic, thus generating a quite heat. In many industrial exothermic polymerization processes, reaction heat is the most serious problem. Also, in radicalic chain polymerization, when the molecular weight of polymer achieved high value rapidly, it may significantly affect the polymer viscosity. Since, polymers have low thermal conductivity, heat transfer and control of temperature becomes very difficult. To produce polymers with well defined characteristics which are related to the process conditions as temperature, initial initiator concentration, reactor temperature has to be controlled effectively during the polymerization.In this work, considering operational constraints in a semi batch polymerization reactor, optimum conditions were determined to obtain desired monomer conversion, number average molecular weight and number average chain length in minimum reaction time. Feed input temperature profile was determined by using mathematical modelling equations and energy balance equations for different operational conditions. Initiator was fed continuously to the reactor. The system was simulated by using advanced simulation programs as MATLAB and Simulink and FORTRAN software packages. Reactor temperature was tried to control by self tuning PID controller. Tuning parameters of controller were obtained by using Genetic Algorithm. After determining parameters, the experimental studies were carried out as first trying experiments using water and polymer experiments. During the polymerization, samples were taken, therefore monomer conversion and viscosity molecular weight were measured. It was seen that genetic algorithm is able to tune the self tuning PID controller efficiently for different situations and therefore to control the temperature of the polymerization reactor.Science Code: 912.1.084Key Words: Self tuning PID control, semi batch polymer reactors, GeneticAlgorithmPage Number: 159Adviser : Prof. Dr. Sebahat ERDOĞAN