Reduction of Transients between Steady States in the Continuous Production of High-Impact Polystyrene

• Published in: Industrial & engineering chemistry research Vol. 44; no. 22; pp. 8354 - 8367
• Main Authors: Luciani, Carla V, Estenoz, Diana A, Meira, Gregorio R, Oliva, Haydée M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 26.10.2005
• Subjects: Applied sciences; Chemical engineering; Exact sciences and technology; Steady state; Production
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie050657z

This work theoretically investigates the reduction of transients during changes of grade in a continuous plant for the production of high-impact polystyrene (HIPS). A mathematical model was developed that predicts the global molecular structure and the melt flow index (MFI). The switching times of the off-specs accumulation period were selected on the basis of the admissible MFI ranges. Smoother transitions and reduced off-specs can be produced through a simple readjustment (with respect to the original plant policy) of the two intermediate chain transfer agent (CTA) loads into the batch dissolver. For the transitions that involve a large difference in their MFIs, the off-specs can be reduced by 60%, with respect to the original plant policy, by including a transient feed of CTA into an intermediate stirred reactor.