Nature-inspired carbon storage and transport: encapsulated CO2 hydrate flow in pipes to imitate blood flow in vessels

Abstract

Hydrate slurry has been recognized as an efficient and cost-effective method for CO2 transport; however, its practical application is constrained by risks of plugging and agglomeration due to hydrate deposition. Here, we propose a new concept for hydrate-based carbon transport utilizing encapsulated hydrate flow, inspired by the transport of red blood cells (RBCs) in blood vessels. Experiments and computational fluid dynamics-discrete element method (CFD-DEM) simulations are conducted to investigate the flow dynamics and dissociation kinetics of CO₂ hydrates encapsulated in RBC-shaped capsules for pipeline transport. The dissociation rate constant is determined by optimizing the model against the experimental dissociation data. The results demonstrate that a higher capsule-to-pipe diameter ratio effectively enhances flow stability, reduces both hydrate dissociation and pressure drop for a given hydrate quantity. Comparative analyses indicate that for various hydrate volume fractions, the pressure drop gradients of the encapsulated hydrate flow are reduced by up to 92% compared to the traditional slurry flow at flow rates from 0.005 to 0.0063m³/s. Additionally, the flow with RBC-shaped capsules consistently exhibit lower pressure drops compared to spherical ones under identical conditions. The improved performance of encapsulated hydrate flow is attributed to differences in flow rheology, viscosity, and particle-particle and particle-wall interactions, demonstrating the potential of encapsulated hydrate transport to enhance carbon storage and pipeline transport efficiency while mitigating risks of pipeline blockage and CO₂ release, critical for process safety in carbon capture and storage (CCS) systems.