Experimental characterization and CFD simulation of a multiphase reactor for carbon mineralization

This study presents an investigation combining experimental characterization and computational fluid dynamics (CFD) simulation of a multiphase stirred vessel equipped with Smith turbines for carbon mineralization applications. Experimental data was collected with four multiphase mixtures including gas-liquid and gas-solid-liquid systems. The present study revealed the superior gas handling capabilities of Smith turbines compared to conventional Rushton geometries, with complete gas dispersion achieved at significantly lower impeller speeds. Gas hold-up measurements demonstrated consistent scaling with the dimensionless parameter ReFrFlG across all configurations. The CFD campaign successfully extended established computational workflows to non-standard geometries. Single-phase and multiphase simulations were carried out using the Reynolds-Averaged Navier Stokes (RANS) equations to solve the fluid motion, and turbulence was modeled employing the k-ε model. It was demonstrated that a computationally efficient steady state approach provides equivalent accuracy to transient methods for the present stirred tank simulation. Simulation of the multiphase systems was carried out employing the Euler-Euler multiphase model and a single bubble diameter was set for each case. The adoption of the Alves bubble diameter correlation leads to predictions close to the experimental gas-liquid flow regime, power consumption and gas hold-up, enabling predictive simulations without experimental bubble size determination. Post-processing of the simulation results revealed detailed mean flow field and turbulent characteristics that cannot be obtained experimentally in gas-solid-liquid systems. The combined experimental and computational methodology provides comprehensive tools for carbon capture reactor design and scale-up, supporting sustainable technology development through enhanced understanding of multiphase transport phenomena and their application to advanced design methods.