Sensitivity analysis of a batch polymerization reactor (original) (raw)

Mathematical Modeling and Optimization of a Semi-Batch Polymerization Reactor

IFAC Proceedings Volumes, 2000

This paper concerns mathematical modeling and optimization of a labscale and a pilot-scale semi-batch free-radical homo-polymerization reactors. A firstprinciples mathematical model is developed by using reaction rate laws available in polymerization literature. The model is validated by comparing the model predictions of monomer conversion, polymer mass fraction, number-average molecular weight, weight-average molecular weight, and polydispersity index to off-line measurements taken in pilot-scale and lab-scale polymerization reactors at DuPont's Marshall Laboratory. The validated model is then used to calculate optimal initiator and monomer feed-rate policies which minimize the polydispersity index of the final polymer product, subject to a set of tight operational constraints.

Trajectory following for the optimization of a batch polymerization reactor

2004

This paper considers the minimization of batch time for an industrial inverseemulsion polymerization reactor in the presence of uncertainty. A first optimization study resulted in the current industrial practice of a semi-adiabatic profile (isothermal operation followed by an adiabatic one), where the switching time between the two modes of operation is updated to meet the terminal constraint on reactor temperature, as well as a constraint on residual raw material levels. However, such a procedure requires several batches for convergence and, in addition, cannot compensate the effect of the within-run disturbances. As an alternative, we propose following a temperature trajectory with respect to conversion, for which the conversion is estimated on-line based on temperature measurements. Simulation results show an improved performance compared to the run-to-run strategy, with the additional advantage that this reduction is obtained immediately, i.e. without having to wait for run-to-run convergence.

Self-Tuning Control of Batch Polymerization Reactor

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 1998

The optimal temperature control of a batch jacketed free radical polymerization reactor with self-tuning PID and conventional PID control methods are considered. The controller is implemented on a digital computer to track precalculated optimal temperature trajectories obtained for different initiator initiation concentration in a batch styrene polymerization reactor. The performance of the self-tuning controller is compared against that of a PID controller. Self-tuning controller provides good, robust control in despite of the nonlinear dynamics of the polymerization reactor system.

Adaptive pole-assignment control of a batch polymerization reactor

Chemical Engineering Science, 1989

This paper is concerned with the control of important polymerization properties in a batch solution polymerization reactor of methylmethacrylate. Properties such as weight average molecular weight or monomer conversion are controlled using an advanced adaptive pole-assignment controller whose performance is compared to that of a generalized minimum variance controller and a fixed gain PID controller. Simulation and experimental results on the batch polymer reactor demonstrate the need for fast on-line measurements in the polvmerization industry as well as the usefulness of this adaptive poleassignment control algorithm. _ _ Tzouanas, V. K., 1985, Theory and experimental evaluation of adaptive control and identification methods. M.Sc. Thesis,

Challenges in Polymerization Reactor Modeling and Optimization: A Population Balance Perspective

IFAC Proceedings Volumes, 2004

In the present article, recent developments on modeling, monitoring, optimization and control of particulate polymerization processes are reviewed. A unified population balance approach is described to follow the time evolution of molecular and morphological polymer properties in batch and continuous polymerization reactors. Recent advances on the online monitoring of "polymer quality" are discussed in the context of available hardware and software sensors. The problem of real-time optimization of polymerization processes under parametric uncertainty is also examined along with its online implementation. Finally, new issues related with the modeling, numerical solution and control of multidimensional PBEs are conferred.

Mathematical Modelling and Simulation of an Industrial Propylene Polymerization Batch Reactor

The aim of this research is to develop a mathematical model for the propylene polymerization batch reactor for a local petrochemical company. The kinetics of polymerization is based on a single type of active sites on Ziegler–Natta catalyst. The model is composed of a number of algebraic and stiff ordinary differential equations which are solved simultaneously using MATLAB script language. The developed model was used to predict the properties of end-product, which include weight and number average molecular weight, polydispersity index (PDI) and melt flow index (MFI). The simulated batch runs were validated against real batch runs for the values of melt flow index. An average absolute error of 10.8 % was achieved.

Optimal control of a high-temperature semi-batch solution polymerization reactor

Proceedings of the 2005, American Control Conference, 2005., 2005

This paper deals with the calculation and realtime implementation of optimal temperature and feed flow rate policies for a high-temperature n-butyl acrylate semibatch solution polymerization reactor. A mechanistic model for solution polymerization of alkyl acrylates in a (semi) batch reactor is derived based on a proposed complex reaction mechanism. The model parameters (reaction rate constants) are estimated from off-line measurements of conversion, average molecular weight, number of terminal double bonds and number of branching points. The model is validated against measurements made in regions different from those of the measurements used for the parameter estimation. By using the model, optimal profiles of three feed (solvent, monomer solution and initiator solution) streams and reactor temperature that minimize a multi-objective performance index, are calculated. The reactor is operated in real-time according to the calculated optimal precipe and measurements are made to validate the true optimality of the recipe. The real-time studies are carried out at DuPont Marshall Laboratory.

Computer optimal control of batch polymerization reactors

Industrial & Engineering Chemistry Research, 1987

This paper presents a theoretical and experimental analysis of the open-and closed-loop optimal control of a batch reactor for the solution polymerization of methyl methacrylate. A novel experimental reactor system with facilities for on-line measurements of polymer quality is employed to verify the theoretical results. A process control computer is used for on-line data acquisition and

Optimization of batch polymerization reactors

Chemical Engineering Science, 1992

ABSTRACT A model for the simulation of suspension polymerization of MMA has been developed, which allows to accounts for the effect of diffusive phenomena on reaction rate and to evaluate molecular weight distribution under non-isothermal conditions. The model has been validated by experimental runs carried out in a laboratory reactor. Obtained results show that an increase of the reaction temperature during the gel effect time can have a favourable influence on the polymer quality. The control of temperature profiles in the reactor is indicated as an interesting operating strategy to be adopted in industrial units.

Nonlinear Control Reactor: an of a Batch Polymerization Experimental Study

1992

This work studies the experimental application of the globally linearizing control (GLC) method to a batch polymerization reactor. The nonlinear controller is implemented on a microcomputer to start up the reactor and then track a precalculated optimal temperature profile. The reactor temperature is controlled by manipulating two coordinated inputs: power to an electrical heat and cooling water flow rate. A reduced-order observer is used to estimate the concentration of initiator and monomer. Systematic tuning guidelines are proposed for the nonlinear control method. The experimental results show the excellent servo and regulatory performance of the nonlinear controller in the presence of modeling and observer initialization errors and active manipulated input constraints. Furthermore, in comparison to a conventional PID controller, the performance of the nonlinear controller is significantly superior, and its tuning is much easier. Dynamics of the control elements The dynamics of the control elements (the control valve, the RTD's, the control valve pressure transducer, and the heater)