MUlti-Scale modeling of fluidized/ebullated bed reaCtors involving anisotropic parTicleS – MUSCATS

DNS and experiments performed at the micro and meso scale are crossed to built and validate closure laws for macro-scale models such as Euler-Euler models. At the end, a comparison between experiments and numerical simulations performed at the macro-scale will allow discussion of the proposed closure laws.

Experimental set ups are built and already allow some mesurements. Non permanent researchers become familiar with numerical tools (PeLiGRIFF, NEPTUNE_CFD). DNS and Euler-Euler simulations with closure laws used for spherical particles are on going work.

Next step will be to deduce from DNS, by statistical analysis, new closure laws and to validate the micro and meso scale experimental results that have still to be obtained. New closure laws have to be included in the numerical EE model.

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Increasing energetic demands require upgrading of heavy crude oils & use of biomass resources processed in fluidized beds involving dense multi-scale multi-phase flows. By joining skills in Fluid Mechanics & Chemical Engineering (IMFT, LGC, IFPEN), project MUSCATS aims at providing predictive and innovative models for design and optimization of liquid-solid reactors with anisotropic particles. Such flows have not been investigated so much as compared to gas-solid fluidized beds with spherical particles. The project comes within the scope of multi-level modeling approach that intends to generate closure laws from DNS or physical experimentation at a local scale to be used in meso-scale models based on Euler-Lagrange (EL) approach and then closures for more coarse-grained models such as Euler-Euler (EE) models. EL is a stage of the multi-level modeling useful to generate closure laws required in EE models based on kinetic theory of granular flow. These EE models are finally used to simulate larger systems and more complex industrial processes.

Three partners are involved in this project. IMFT has a strong experience since more than twenty years on multi-scale approaches used for the development of an EE numerical code, NEPTUNE_CFD, for the design and the optimization of industrial fluidized bed reactors. To achieve this goal, this laboratory also carries out experiments at particle scale to inform and validate models. LGC has more than thirty years experience in the design and development of fluidized beds from small scale to industrial scale and works together with IMFT since almost ten year in the development of the EE approach for fluidized bed numerical simulations. IFPEN is involved in the design of industrial scale installations in various domains, like bio-sourced fuels and provides public players and industry with efficient, economical, clean and sustainable technologies. It has developed for ten years Code PeliGRIFF for DNS or EL simulations of dense particle flows.

In MUSCATS project, numerical simulations at micro, meso and macro scales will be developed with these two codes. Also, experiments are planned in two set-ups to be built at intermediary scales in order to cover the full upscaling range from micro to macro scale (Experiment #1 at micro-meso scale and experiment #2 at meso-macro scale). Experiments at the micro-meso scale (exp. #1) will be performed in a confined thin-gap channel in order to reduce the degrees of freedom of cylinders motions and to allow precise and robust measurements of the dynamics. Local experimental exploration of the dynamics will be compared to DNS using PeliGRIFF for its validation. Then DNS in an unconfined geometry (periodic box) are planned to provide more generic closure laws for meso-scale EL models. Euler-Lagrange meso-scale simulations of both experiments #1 and #2 (fluidized column) will be performed with the EL version of PeliGRIFF and compared to measurements at this meso-scale to check representativeness of the closure laws. Then, statistical analysis of these simulations is planned to develop EE closure laws based on the Kinetic Theory of Granular Flows. Euler-Euler numerical simulations will be performed with the EE code NEPTUNE_CFD concerning experiment #2 to discuss the closure laws obtained at the upscaling final stage. Also, measurements at the real industrial scale, which are quite hard to obtain, will be supervised by IFPEN and compared to EE calculations.
Covering all the steps of the upscaling process, MUSCATS project offers the possibility to provide innovative knowledge and numerical models concerning liquid-solid fluidized beds with anisotropic particles.