MULTIVARIABLE NONLINEAR CONTROL OF A CONTINUOUS POLYMERIZATION REACTOR - AN EXPERIMENTAL-STUDY

This experimental work concerns the multivariable nonlinear control of a continuous stirred-tank polymerization reactor. The globally linear izing control (GLC) method is implemented to control conversion and te mperature in the reactor in which the solution polymerization of methy l methacrylate takes place. Control of conversion and temperature is a chieved by manipulating the flow rate of an inlet initiator stream and two coordinated heat input variables. Conversion is inferred from on- line measurements of density and temperature. A reduced-order state ob server is utilized to estimate the concentrations of monomer, initiato r and solvent in the reactor. The concentration estimates are used in the control law. This study demonstrates the considerable computationa l efficiency of the nonlinear controller, which is implemented on a mi crocomputer. The experimental results show the excellent performance o f the controller in the presence of active state and input constraints . A systematic approach is also given for the synthesis of output feed back controllers within the GLC framework for processes with secondary outputs.