CONSTRUCTAL DESIGN APPROACH FOR CARBON DIOXIDE ADSORPTION SYSTEMS

Abstract

Current carbon capture and storage (CCS) benchmark technologies and materials are both energy and economically costly. Therefore, it hopes to rely on uncovering combinations of designs or materials to provide the performance leap to scale up the CCS deployment to meet the most optimistic Intergovernmental Panel on Climate Change (IPCC) projections and socioeconomic shared pathways to mitigate global warming. While the search for advanced materials for carbon capture has drawn much of the efforts to enhance the so-called productivity (CCPr), i.e., CO2 mols per volume of CC material per cycle for high levels of purity for CO2 recovery, there is an opportunity to investigate before-hand how those materials would fare energy wise (PE) (total energy expenditure by total amount of CO2 mols captured) in the reactor. This work presents a formulation based on the Constructal Theory to explore how the features of the materials themselves (absorptivity, molecular diffusivity, density), the packing (pellets shape and size, effective diffusivity, specific capturing rate, porosity), and the configuration of a column packed-bed reactor affects the energy penalty (PE). The investigation is theoretical and numerical by modeling the CO2 mass balance in a prescribed and constant mobile phase flow rate (initially CO2-rich exhaust gases) isothermal 1d tubular packed-bed reactor and the coupling with CO2 mass balance at the pellet level with linear driving force model – both are saturated porous media. The simulations were performed using newly developed Python code and commercial software. The model was turned nondimensional, and the influence of the adapted Peclet and Damkhöler numbers was explored, which showed reverse trends in the indices CCPR and PE. It showed the trade-off between the resistances to adsorb CO2 and the other features of the reactor’s design, providing insights into how those systems may evolve.