Nonlinear Control of Free-Radical Polymerization Reactors

Abstract

Free-radical polymerization reactors exhibit autoacceleration kinetics, exothermicity and limited heat removal that pose a sensitive, nonlinear, interactive, multivariable control problem for batch, semibatch and continuous operation. We address a tracking strategy with a nonlinear feedforward-feedback control scheme. Consideration of measured inputs (which are not controls) yields time-varying nonlinear systems which admit coordinate changes to linear autonomous Brunovsky canonical forms where: realizable tracking reference inputs and states are established, and the feedbacks are constructed and tuned. The coordinate change yields linear, noninteractive control designs. The tracking control strategy is able: to take an empty reactor to a stable continuous operation (which, otherwise is open-loop unstable), and to provide a stable periodic continuous operation.