Cost model & CAPEX

Pipeline diameter (Darcy–Weisbach)

How the pipeline diameter is derived from the CO₂ flow.

CAPEX depends on the pipeline diameter, which CO2GIS derives once for the whole route from the CO₂ mass flow rate using the Darcy–Weisbach relation.

D = \left( \frac{8\,\lambda\,M^{2}}{\pi^{2}\,\rho\,(\Delta p / L)} \right)^{1/5}

Symbols

Symbol	Meaning	Default	Unit
$D$	pipeline inner diameter	computed	m
$\lambda$	Darcy friction factor	0.015	—
$M$	CO₂ mass flow rate	your input	kg/s
$\rho$	CO₂ density (supercritical)	827	kg/m³
$\Delta p / L$	admissible pressure drop	0.02	MPa/km

The diameter is constant along the route — computed once, then used for every segment. $\Delta p / L$ is entered in MPa/km in the interface and converted internally to Pa/m.

References

Friction factor $\lambda$ and admissible pressure drop $\Delta p / L$ : Seixas, J. et al. (2015). Roteiro Nacional para a Captura e Armazenamento de Dióxido de Carbono — CCS Roadmap Portugal. Universidade de Évora / Global CCS Institute. hdl.handle.net/10174/17160
CO₂ density $\rho$ (supercritical): Kim, T. W., Yoon, H. C., & Lee, J. Y. (2024). Review on CCS from source to sink; part 1: essential aspects for CO₂ pipeline transportation. International Journal of Greenhouse Gas Control, 137, 104208. doi:10.1016/j.ijggc.2024.104208

The Darcy–Weisbach relation itself is classical fluid mechanics; the full derivation for CO₂ pipelines is in the dissertation.

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