Non-linear inferential control of packed-bed reactors

Two distinct types of inferential control strategies for the single-input/single-output (SISO) system of a packed-bed reactor are investigated, i.e. non-linear inferential control (NLIC)—the state feedback control (SFC) scheme—and linear inferential control (LIC)—the internal model control (IMC) scheme—to deal with non-linear and unmeasured output process control problems, and the effects of modelling errors and measurement noise on control system performance. The basic structure of an inferential control system is coupled with a state estimator and a controller consisting of the process model and a filter with adjustable parameter, A non-linear estimator is used to estimate the state variables of the process from the temperature measurements. Simulation results have shown that the performances of the SFC scheme are much better than those of the IMC scheme, in spite of modelling errors and measurement noise. The results also indicate that a substantial improvement in control is possible using NLIC.