Hans Schuler

Calorimetric-state estimators for chemical reactor diagnosis and control: review of methods and applications

Abstract The advanced control of stirred tank reactors can be based on models which contain exclusively the conservation equations of energy and species, without using further sophisticated modelling terms. These basic models allow determination of the instantaneous heat production, the conversion and the reactive production rate from state estimation algorithms. These “calorimetric”-state estimators are based on easily available signals, like temperatures, pressures, flows, and on credible model information, like conservation equations. The design of these estimators is quite simple, as they are based on linear models. This contribution gives an overview of control applications which use these state estimators based on calorimetric principles. Available models, signal processing principles and control structures will be reviewed. These advanced control loops assist basic automation structures in improving dynamic response behaviour, control performance and disturbance rejection. They introduce new strategies into reactor control.

Real-time estimation of the chain length distribution in a polymerization reactor

Abstract The method of Kalman filtering has been used to obtain on-line state estimates of a batch styrene polymerization reactor. The temperatures of the plant and the refractive index of the reaction mixture are given as measurement signals to a Kalman filter realized in a process computer. Based on mathematical process models, one can reconstruct, from these measurement variables, the conversions of reactants and the chain length distribution of the produced polymer. These (calculated) variables provide a better insight into the actual process state and enable the characterization of product quality during production.

Real-time estimation of the chain length distribution in a polymerization reactor—II. comparison of estimated and measured distribution functions☆

Abstract In Part I of this series (1985, Chem. Engng Sci.40, 1891) the chain length distribution of polystyrene produced in a batch stirred tank reactor was estimated. The estimation procedure applied was based on a mathematical process model and the measured signals of temperature and refractive index. In the present paper these estimated distribution functions are compared to the measured chain length distributions obtained from a gel permeation chromatograph. The estimated distributions compare favourably with the measurements. The state estimator can therefore be applied in the wider context of supervision and control of polymerization reactors.