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- Title
Pore-scale study of CO<sub>2</sub> desublimation and sublimation in a packed bed during cryogenic carbon capture.
- Authors
Lei, Timan; Luo, Kai H.; Hernández Pérez, Francisco E.; Wang, Geng; Yang, Junyu; Restrepo Cano, Juan; Im, Hong G.
- Abstract
Cryogenic carbon capture (CCC) is an innovative technology to desublimate $\text {CO}_2$ out of industrial flue gases. A comprehensive understanding of $\text {CO}_2$ 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 $\text {CO}_2$ desublimation and sublimation for different operating conditions, including the bed temperature (subcooling degree $\Delta T_s$), gas feed rate (Péclet number $Pe $) and bed porosity ($\psi$). The $\text {CO}_2$ desublimation and sublimation properties are reproduced. Interactions between convective $\text {CO}_2$ supply and desublimation/sublimation intensity are analysed. In the single-grain case, $Pe $ is suggested to exceed a critical value $Pe _c$ at each $\Delta T_s$ to avoid the convection-limited regime. Beyond $Pe _c$ , the $\text {CO}_2$ capture rate ($v_c$) grows monotonically with $\Delta T_s$ , indicating a desublimation-limited regime. In the packed bed case, multiple grains render the convective $\text {CO}_2$ supply insufficient and make CCC operate under the convection-limited mechanism. Besides, in small- $\Delta T_s$ and high- $Pe $ tests, $\text {CO}_2$ desublimation becomes insufficient compared with convective $\text {CO}_2$ supply, thus introducing the desublimation-limited regime with severe $\text {CO}_2$ capture capacity loss ($\eta _d$). Moreover, large $\psi$ enhances gas mobility while decreasing cold grain volume. A moderate porosity $\psi _c$ is recommended for improving the $\text {CO}_2$ capture performance. By analysing $v_c$ and $\eta _d$ , regime diagrams are proposed in $\Delta T_s$ – $Pe $ space to show distributions of convection-limited and desublimation-limited regimes, thus suggesting optimal conditions for efficient $\text {CO}_2$ capture. This work develops a viable LB model to examine CCC under extensive operating conditions, contributing to facilitating its application.
- Subjects
CARBON sequestration; POROUS materials; INDUSTRIAL gases; FLUE gases; TECHNOLOGICAL innovations
- Publication
Journal of Fluid Mechanics, 2024, Vol 990, p1
- ISSN
0022-1120
- Publication type
Article
- DOI
10.1017/jfm.2024.351