Polymerization reactor control

H. Seki, M. Ogawa, S. Ooyama, K. Akamatsu, M. Ohshima, and W. Yang. Industrial application of a nonlinear model predictive control to polymerization reactors. Control Engineering... 

Fig. 1 Design of optimal batch polymerization reactor controls. (View this art in color at www.dekker.com.)...

For all the reasons presented above, research and technical activities are very intense and diversified in the field of polymerization reactor control, so that no sort of general control solution can be provided without taking into consideration the particular characteristics of the analyzed polymerization system [3]. 

The scenario described in the previous paragraphs probably explains the large number of surveys that have been published in the open literature about the control of polymerization reactors. Therefore, the main objective of this chapter is not reviewing the whole field of polymerization reactor control, but presenting the main features and discussing the main trends of the area [3]. Illustrative examples are selected among the many publications in the field. Detailed presentation and analysis of the different proposed control approaches [4-10] and of the distinct used monitoring techniques [11-14] can be found in the available surveys. 

Ray, W. H. (1986) Polymerization reactor control, presented at the ACC, Boston, Mass., June. 

The really interesting issues in control of polymerization are not in the control of the operating conditions (flow, temperature, etc.). These loops are controlled in much the same way as would be done in any other chemical process. The real interest is in the control of polymer properties (monomer conversion, MW, particle size, copolymer composition, etc.). The next sections will review a number of control studies, each using a different approach to deal with the control problems specific to polymer property control (lack of sensors, one-sided control, nonlinearities, etc.). This will be followed by a discussion of an alternative approach to polymerization reactor control, statistical process control, and a discussion of the optimization of operating trajectories. 

Penlidis, A., MacGregor, J. F., and Hamielec, A. E. (1985) Continuous emulsion polymerization reactor control, Proc. 1985 American Control Conf., IEEE, Boston. 

Adebekun, A. K. and Schork, F. J. (1989b) Continuous solution polymerization reactor control. 2. Estimation and nonlinear reference control during methylmethacrylate polymerization, Ind. Eng. Chem. Res. 28, 1846-61. 

Ratio control is a form of feedforward control which is widely used in the chemical industry and has proven very useful in polymerization reactor control. As is evident from its name, its purpose is to keep the ratio of two process variables at a... 

W. H. Ray, Process modeling for polymerization process operation and control , presented at the Tutorial on Polymerization Reactor Control, AIChE Annual Meeting, November, 2003. 

B. R. Maner, F. j. Doyle III, Polymerization reactor control using autoregressive-plus Voltera-based MPC , AIChEJ., 1997, 43, 1763. 

In order to achieve the production of a polymer resin with specified end-use properties, the availabiUty of efficient control techniques may not be enough. The gap between the polymerization process and the control technique must be bridged with accurate and robust instrumentation for online monitoring so that the controller can be fed with the current state of the process. Figure 6.1 illustrates the control configurations normally used to control the process. The lack of such instruments, which must be able to measure and monitor the quality of the polymer resin, has been long recognized as the most important problem in the field of polymerization reactor control [7]. Several studies provide... 

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