Periodic Reporting for period 1 - MOD3CAT (Modelling of three-phase flows with catalytic particles)
Periodo di rendicontazione: 2023-01-01 al 2025-06-30
In this research we focus on three-phase gas-solid-liquid multi-component systems with catalytic particles, which are frequently encountered in industrial applications, but have not been tackled fundamentally before due to their complexity.
Dense multi-phase flows have been intensively researched because of their scientifically interesting transport phenomena and industrial applications. Considerable progress has been made for gas-solid and gas-liquid two-phase flows. However, multicomponent three-phase flows with catalytic reactions have received relatively little attention despite their importance for the production of clean synthetic fuels, base chemicals, and many other products. Multiphase transport phenomena in such systems are poorly understood due to their complexity. Therefore, the design of such processes is cumbersome, requiring extensive experimentation. In addition, the process operation is often far from optimal in terms of energy and feedstock utilization. Therefore, significant improvements are required to boost the efficiency of three-phase systems, which demands for a better understanding of the transport fundamentals and complex interplay with catalytic reactions and availability of predictive tools.
The main underlying problem is the complex interplay between transport phenomena and catalytic reactions, introducing a wide range of length scales: suspended catalyst particles have a size of 100-200 μm, whereas the diameter of industrial reactors is 5–10 meters. To tackle this type of problem, a proper problem decomposition needs to be adopted. At the scale of the particles, the catalytic reactions need to be considered as well as the transfer of species and heat to the continuous (liquid) phase. The latter is accounted for by closure laws for mass, momentum and heat exchange that feed so-called Euler-Lagrange models, which can then be used to compute the flow structures on a much larger (industrial) scale. The key innovative aspect of this proposal is the integrated approach including incorporation of multi-component catalytic reactions and supporting experimental validation on basis of one-to-one comparison of the computational results with experiments.
Dense multi-phase flows have been intensively researched because of their scientifically interesting transport phenomena and industrial applications. Considerable progress has been made for gas-solid and gas-liquid two-phase flows. However, multicomponent three-phase flows with catalytic reactions have received relatively little attention despite their importance for the production of clean synthetic fuels, base chemicals, and many other products. Multiphase transport phenomena in such systems are poorly understood due to their complexity. Therefore, the design of such processes is cumbersome, requiring extensive experimentation. In addition, the process operation is often far from optimal in terms of energy and feedstock utilization. Therefore, significant improvements are required to boost the efficiency of three-phase systems, which demands for a better understanding of the transport fundamentals and complex interplay with catalytic reactions and availability of predictive tools.
The main underlying problem is the complex interplay between transport phenomena and catalytic reactions, introducing a wide range of length scales: suspended catalyst particles have a size of 100-200 μm, whereas the diameter of industrial reactors is 5–10 meters. To tackle this type of problem, a proper problem decomposition needs to be adopted. At the scale of the particles, the catalytic reactions need to be considered as well as the transfer of species and heat to the continuous (liquid) phase. The latter is accounted for by closure laws for mass, momentum and heat exchange that feed so-called Euler-Lagrange models, which can then be used to compute the flow structures on a much larger (industrial) scale. The key innovative aspect of this proposal is the integrated approach including incorporation of multi-component catalytic reactions and supporting experimental validation on basis of one-to-one comparison of the computational results with experiments.
In the MOD3CAT project, substantial progress has been made toward modeling and simulating complex three-phase slurry bubble column reactors. Advancements include the development of an advanced Direct Numerical Simulation (DNS) framework featuring adaptive mesh refinement (AMR) on staggered grids, effectively resolving thin boundary layers. This novel computational approach, incorporating a robust algebraic Volume-of-Fluid (VOF) method and efficient parallelization strategies, provides unprecedented accuracy and speed for detailed simulations of fluid-solid and fluid-fluid interactions in reactive multiphase flows.
Complementing these developments, an Euler-Lagrange (E-L) modeling framework has been successfully extended to simulate bubble-liquid systems, incorporating modules for turbulence, interphase mass transfer, and chemical reactions. Additionally, an innovative discrete element method (DEM) enables simultaneous simulation of bubbles and catalytic particles, coupled with coarse-graining and stochastic techniques for realistic catalyst loadings. Concurrently, novel experimental setups utilizing optical fiber sensors and advanced digital imaging techniques are under development, facilitating validation and deepening our understanding of three-phase hydrodynamics and mass transfer processes.
Complementing these developments, an Euler-Lagrange (E-L) modeling framework has been successfully extended to simulate bubble-liquid systems, incorporating modules for turbulence, interphase mass transfer, and chemical reactions. Additionally, an innovative discrete element method (DEM) enables simultaneous simulation of bubbles and catalytic particles, coupled with coarse-graining and stochastic techniques for realistic catalyst loadings. Concurrently, novel experimental setups utilizing optical fiber sensors and advanced digital imaging techniques are under development, facilitating validation and deepening our understanding of three-phase hydrodynamics and mass transfer processes.
The MOD3CAT project has advanced significantly beyond the state of the art through the creation of a unique staggered, adaptively refined mesh method for numerically solving the Navier-Stokes equations in multiphase flow simulations. This methodology offers enhanced accuracy and conservation properties over existing techniques, particularly in managing high density ratios and complex interface dynamics, thus providing a versatile tool applicable to a wide range of CFD challenges.
Furthermore, the pioneering use of Euler-Lagrange-Lagrange (ELL) techniques for simulations of bubble-particle interactions in three-phase systems, that will be supported by novel experimental validation approaches such as tailored Particle Image Velocimetry (PIV) and optical fiber measurements, significantly extends the current capabilities in multiphase reactor analysis. To ensure the broader impact and further uptake of these advancements, future work will focus on continued validation, refinement of computational efficiency.
Furthermore, the pioneering use of Euler-Lagrange-Lagrange (ELL) techniques for simulations of bubble-particle interactions in three-phase systems, that will be supported by novel experimental validation approaches such as tailored Particle Image Velocimetry (PIV) and optical fiber measurements, significantly extends the current capabilities in multiphase reactor analysis. To ensure the broader impact and further uptake of these advancements, future work will focus on continued validation, refinement of computational efficiency.