%0 Journal Article
%@ 0022-1120
%A Lei, Timan
%A Luo, Kai H
%A Perez, Francisco E Hernandez
%A Wang, Geng
%A Yang, Junyu
%A Cano, Juan Restrepo
%A Im, Hong G
%D 2024
%F discovery:10199840
%I CAMBRIDGE UNIV PRESS
%J Journal of Fluid Mechanics
%K Convection in porous media, solidification/melting, coupled diffusion and flow
%T Pore-scale study of CO2 desublimation and sublimation in a packed bed during cryogenic carbon capture
%U https://discovery.ucl.ac.uk/id/eprint/10199840/
%V 990
%X Cryogenic carbon capture (CCC) is an innovative technology to desublimate CO2 out of industrial flue gases. A comprehensive understanding of CO2 desublimation and sublimation is essential for widespread application of CCC, which is highly challenging due to the complex physics behind. In this work, a lattice Boltzmann (LB) model is proposed to study CO2 desublimation and sublimation for different operating conditions, including the bed temperature (subcooling degree ∆Ts), gas feed rate (Péclet number Pe) and bed porosity (ψ). The CO2 desublimation and sublimation properties are reproduced. Interactions between convective CO2 supply and desublimation/sublimation intensity are analysed. In the single-grain case, Pe is suggested to exceed a critical value Pec at each ∆Ts to avoid the convection-limited regime. Beyond Pec, the CO2 capture rate (vc) grows monotonically with ∆Ts, indicating a desublimation-limited regime. In the packed bed case, multiple grains render the convective CO2 supply insufficient and make CCC operate under the convection-limited mechanism. Besides, in small-∆Ts and high-Pe tests, CO2 desublimation becomes insufficient compared with convective CO2 supply, thus introducing the desublimation-limited regime with severe CO2 capture capacity loss (ηd). Moreover, large ψ enhances gas mobility while decreasing cold grain volume. A moderate porosity ψc is recommended for improving the CO2 capture performance. By analysing vc and ηd, regime diagrams are proposed in ∆Ts–Pe space to show distributions of convection-limited and desublimation-limited regimes, thus suggesting optimal conditions for efficient CO2 capture. This work develops a viable LB model to examine CCC under extensive operating conditions, contributing to facilitating its application.
%Z This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.