Constructal design of a mineral carbonation system for post-combustion carbon capture

Carbon capture, utilization, and storage (CCUS) has been recognized as a crucial path to mitigating the effects of greenhouse gas emissions on climate change. Mineral Carbonation (MC) processes are among the safest and most promising alternatives for CCUS due to on-site product stability. However, technical challenges need to be overcome to scale up the technology, such as energy penalties and sufficiently fast kinetics. The constructal design method provides a path to achieve those goals altogether. This paper first addresses the constructal design of a mineral carbonation porous bed reactor for post-combustion carbon capture. Analytical models allowed to obtain optimized parameters for the aspect ratio of the elemental volume, which is then packed in hierarchical flow structures to minimize pressure losses (energy penalties). Numerical full-scale models show the validity of the proposed relations. The trade-off between pressure losses and rate of reaction is then explored by the ratio with which the first construct is filled with reacting material. Results for the multi-scale design show that it is possible to associate geometric configurations with pressure drops for the carbon capture devices and to seek configurations that lead to lower energy expenditure. The findings can be applied for other types of fixed bed reactors.