(48c) Modeling CO2 Adsorption in an Euler-Lagrange Framework Accounting for Pseudo-Turbulence and Intraparticle Diffusion

As global temperatures rise, there is an ever-increasing need for improved carbon capture technology. CO₂ adsorption has emerged as a promising method of CO₂ removal for both post-combustion capture and direct air capture applications. Amine-based sorbents are a promising choice for both applications due to their ability to capture a relatively high amount of CO₂ with relatively low energy costs, even at low concentrations of CO₂. This technology is currently not yet mature enough to be implemented on a large scale, in part due to challenges in scaling up. The flow physics and chemistry taking place at the microscale (i.e., at the scale of individual sorbents) control macroscale behavior in the reactor. Because such effects are not well understood, they are frequently excluded from numerical simulations. The aim of this work is to model CO₂ adsorption using the most state-of-the-art models available to account for microscale thermo-chemistry and flow physics. Modeling is performed in NGA2, an open source multi-phase flow solver that solves the volume-filtered Eulerian-Lagrangian equations. Subgrid-scale models for pseudo-turbulent velocity fluctuations and pseudo-turbulent heat/mass fluxes are employed. These terms account for turbulent mixing induced by particles, which is unresolved in Eulerian-Lagrangian simulations. Additionally, unlike many simulations that model chemical kinetics using a simple linear driving force, intrinsic kinetics are employed and corrected using an effectiveness factor to account for intraparticle diffusion limitations within the particles. Including this effectiveness factor allows transport inside the particle to be accounted for in a computationally efficient manner. This work will look at flow through random arrangements of solid sorbents for both fixed and fluidized systems. The relative importance of the pseudo-turbulent terms and intraparticle diffusion will be discussed.