Process Model for Styrene and n‑Butyl Acrylate Emulsion Copolymerization in Smart-Scale Tubular Reactor

• Published in: Industrial & engineering chemistry research Vol. 55; no. 2; pp. 472 - 484
• Main Authors: Pokorný, Richard, Zubov, Alexandr, Matuška, Petr, Lueth, Fabian, Pauer, Werner, Moritz, Hans-Ulrich, Kosek, Juraj
• Format: Journal Article
• Language: English
• Published: American Chemical Society 20.01.2016
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.5b02909

Real-time optimization-based control methodologies in emulsion (co)­polymerization allow achievement of a significant intensification of the process and increase of the product quality. This paper describes the development of the fast and computationally simple process model of continuous styrene and n-butyl acrylate emulsion copolymerization for use in nonlinear model predictive control (NMPC) of a smart-scale tubular reactor. The model predictions agree well with experimental data for monomer conversion, copolymer composition, temperature profile, average particle size, and number-average molecular weight. To account for the slower reaction rate at the beginning of the reaction, the model incorporates a thermodynamic description of comonomer partitioning between particle, water, and droplet phases based on Morton equations. For the purpose of the process model, a simple empirical function representing the solution of Morton partitioning was implemented. The number concentration of particles was estimated from measured monomer conversion profiles, as the predictions by first-principle nucleation models generally provide values substantially different from experiments. After the model incorporation into a framework for online state estimation and control, it will be used for open- and closed-loop control of the smart-scale tubular reactor.