Molecular composition indirect estimates

Polymerization process control can benefit significantly from using online state estimation techniques. In general, online control of polymer properties such as molecular weight, MWD, copolymer composition, MI, density, etc. is difficult, mainly because of the lack of adequate online or in-process sensors. Therefore, many of these polymer property parameters are controlled indirectly by controlling first-level process variables such as temperature, pressure, and the flow rates of various reactants, solvents, and catalysts. When some deviations in polymer properties are detected through laboratory sample analysis, certain reactor variables need to be adjusted. Extensive plant experience might be required to make such process adjustments, or model-based online state estimator can be used. 

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