Dynamic Modeling of Industrial Loop Reactors for Catalytic Ethylene (Co)polymerization: Pressure Safety Valves

• Published in: Macromolecular reaction engineering 2022-12, Vol.16 (6), p.n/a
• Main Authors: Krallis, Apostolos, Al‐haj Ali, Mohammad, Kanellopoulos, Vasileios
• Format: Article
• Language: English
• Subjects: Catalysts; Dynamic models; Emergency response; Equations of state; Ethylene; Flow velocity; Microbalances; modelling; Nuclear safety; polymer reaction engineering; Polymerization; polymerization technology; polyolefins; Reaction kinetics; Reactors; Safety valves; Slurries; Transport properties
• ISSN: 1862-832X; 1862-8338
• DOI: 10.1002/mren.202200009

In industrial loop reactors, for catalytic ethylene (co)polymerization, the heat produced by polymerization can result in temperature and pressure increase, which in turn can lead to reactor breakage, explosion, and consequent release of toxic/flammable fluids in the environment. To predict the reactor temperature and pressure during ethylene (co)polymerization and assess the performance of presure safety valves (PSVs) in response to emergency accidents, an integrated mathematical approach is followed including catalyst kinetics, thermodynamics, and transport properties modeling. A catalytic ethylene (co)polymerization kinetic model is used to predict the catalyst activity variation with respect to reactor temperature and the heat produced by the polymerization reaction during a reaction runaway. The Sanchez–Lacombe equation of state (SL EOS) is utilized in order to predict the reactor pressure for different slurry mixture compositions and the slurry densities at different temperatures, pressures and solids weight fractions. Dynamic macroscopic mass and energy balances are derived to calculate the dynamic evolution of concentrations of the various molecular species as well as the temperature changes in the loop reactor. The model can predict the temperature and pressure increase rates and the maximum flow rate at the PSVs during the runaway. Ensuring the safe operation of industrial‐scale loop reactors is one of the most important safety aspects in the catalytic ethylene (co)polymerization production process. For this reason, it is of profound significance to design properly the pressure safety valves when a loop reactor is in operation or assess the capacity of existing ones when a new catalyst is used.