Nature-inspired carbon storage and transport: Investigating hydrate dissociation and flow dynamics of encapsulated CO2-TBAB hydrates in pipelines

Efficient and safe CO2 transport is a critical component of carbon management strategies, but conventional high-pressure pipeline transport requires substantial energy for compression and carries inherent high-pressure safety risks. Encapsulated-hydrate transport offers a lower-pressure, modular alternative that mitigates leakage risk and reduces dependence on large compressor infrastructure. Here, we investigate the transport performance and dissociation behaviour of biomimetically encapsulated CO2–TBAB hydrates for pipeline applications. Building on earlier proof-of-concept work, this study combines controlled dissociation experiments, bench-scale tests and transient CFD–DEM simulations to quantify (i) hydrate dissociation kinetics as a function of temperature and moderate pressure, (ii) the threshold velocity required for stable capsule transport across varying pipe lengths and hydrate volume fractions, and (iii) the energetic and mechanical penalties imposed by increased flow rate and pipe geometry. Experimentally derived dissociation constants follow an Arrhenius trend and indicate strongly reduced short-term mass loss at lower temperatures; operating at ∼10 °C with modest overpressure (2.5 bar) yields simulated 5-min dissociation losses of ≈1.3 %. CFD–DEM results show that the threshold velocity increases with both hydrate volume fraction (HVF) and transport distance (e.g., from 0.24 → 0.53 m s−1 across the tested matrix), and that pressure drop and wall-shear hot-spots amplify rapidly with HVF, pipe length and bend severity. Hydrate transport efficiency (HTE) is maximised at intermediate HVF for long runs (10 % HVF at 10 m in this study), while increasing Reynolds number above threshold reduces HTE because pumping power grows faster than residence-time benefits. These findings quantify operational windows and mitigation strategies and demonstrate that encapsulated-hydrate transport can be a viable, lower-pressure alternative for short–to–medium distance CO2 delivery with favourable safety and energy trade-offs compared with conventional approaches.