Optimization and control of semi-batch polymerization reactor

Polymers are used in variety of growing fields in our daily life. A polymer product is composed of macromolecules with different molecular weights, and the processability and subsequent utility of a polymer product depend greatly on the molecular weight distribution (MWD) of the macromolecules. Complex reaction kinetics and mechanisms, physical changes and transport effects, non-ideal mixing, and strong process nonlinearity characterize polymerization processes. Since the conversion and molecular weight are influenced strongly by the polymerization reactor operation conditions, the production of a high quality polymer requires optimal operation of the reactor.In this project, the temperature control of the semi-batch styrene polymerization reactor was investigated by self-tuning PID (STPID) control method. The controller tuning parameters were determined by Genetic Algorithm (GA) which is a search technique based on natural selection and natural genetic rules.The work was planned in two parts as theoretical and experimental. In theoretical part, mass and energy balance equations which were developed for this system and feeding profile equation was used for the simulation purposes by using a computer programme. Then, optimum generation number, crossover probability and mutation probability was found for GA. Controller parameters were found through this simulation program with GA and these parameters were used in the optimal temperature control of reactor by STPID. During the polymerization samples were taken and monomer conversion was determined to check the performance of control applied to this system. Also from these samples molecular weight was calculated.After these two parts, experimental and theoretical results were compared and found that STPID is a good way to control the temperature of semibatch styrene polymerization reactor.