SUMMARYThis article presents preliminary uid dynamic simulation results of ethylene polymerization dense uidized bed using the two-phase ow numerical code ESTET-ASTRID developed by Electricità e de France for CFB boilers and based on the two-uid modelling approach. The continuous phase consists of gas and the dispersed phase consists of catalyst particles. The particle uctuating motion is modelled using two-separate transport equations, on the particle kinetic energy and the uid-particle covariance, developed in the frame of kinetic theory of granular medium accounting for particle-particle and uidparticle interactions. Time-dependent 2D and 3D simulations have been performed for industrial and pilot reactor operating conditions. The numerical predictions are in good qualitative agreement with the observed behaviour in terms of bed height, pressure drop and mean ow organization, such as the down falling of the PE particle layer along the walls. Moreover, these simulations help to provide information about instantaneous and time-averaged solid concentration and velocity ÿelds. Characteristic mechanisms and in uence of model closure assumptions on ow predictions are also investigated. Finally, such numerical simulations look very powerful, when validated on exhaustive data collection, to improve design and performance of industrial facilities and to provide insight into the complex physical mechanisms involved.

Massively parallel numerical simulation using up to 36,000 CPU cores of an industrial-scale polydispersed reactive pressurized fluidized bed with a mesh of one billion cells. (2020) Powder Technology, 366. 906-924. ISSN 00325910 .