(155a) Using Novel Multiphase Simulation Techniques for Innovative Process Development – Case Studies in PO Processes

Multiphase simulations have been the topic of extensive research and developments giving deep insights and improved understanding of phenomenon observed in a wide variety of chemical process industry. Their application to polymerization process has been also widely reported but the long road to full understanding in industrial terms remains full of potholes.

Borstarâ„¢ PE or PP processes include a combination of (i) slurry loop and (ii) gas-phase fluidized-bed reactor(s) for polymerizing ethylene or propylene. Both kinds of reactors operate in a multiphase regime with either liquid or gas in presence of growing particles that range from microns to millimeter sized particles. For taking advantage of the Borstarâ„¢ process, it becomes vital to generate meaningful cause-and-effect understanding of particle-related phenomenon that occur in each kind of the reactor and on the how the polymer properties are developing with time & space.

Standard DPM & TFM approaches for modelling either of these polymerization reactors may be sufficient for understanding fluid-particle interactions at limited scales, obtaining simulation results on industrial sized reactors requires substantial computation demands. In addition, including polymerization mechanisms in order to perform ‘warm’ reactor simulations remains an even larger challenge.

Borealis has been working with academic partners who have made significant progress in how state-of-the-art multiphase models can be extended to allow understanding of fluid-particle segregation for large simulation geometries in reasonable time frame and incorporate reaction mechanisms. By carrying out such ‘warm’ reactor simulations Borealis has been able to obtain detailed information on the polymer particle characteristics. This information has helped us further optimize the operation of our reactors and enhance their operating window. Consequently, the availability of our polymerization reactors is greatly improved and led to optimization in scheduling.

Two separate case studies dealing with large scale simulations of multiple-leg loop reactors as well as gas-phase fluidized bed reactors will be shared to demonstrate the advantage such approach provides.