Supercritical CO2 Pipeline Hydraulic Calculator
CCUS Infrastructure Engineering: Model non-linear dense-phase supercritical $CO_2$ fluid properties, frictional pressure gradients, and allowable pipeline transmission distance above the critical point.
Pipeline Flow & Sizing
Dense-Phase Operating Conditions
Pipeline Hydraulic Performance Output
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Dense-Phase Supercritical CO2 Pipeline Hydraulics
Long-distance pipeline networks transport captured carbon from emitter clusters to offshore or onshore geological storage hubs.
1. Frictional Gradient & Darcy-Weisbach Formulation
ΔP = f · ( L / D_inner ) · ( ρ · V² / 2 ) Re = ( ρ · V · D_inner ) / μ
2. Operating Pressure Corridor
P_operating > P_critical = 73.77 bar (Strictly Single-Phase Dense Fluid) P_max ≤ 0.72 · SMYS · ( 2 · t / D_outer ) (ASME B31.4 Hoop Stress Limit)
Frequently Asked Questions
Why is carbon dioxide transported in dense/supercritical phase in CCUS pipelines?
Gaseous $CO_2$ has low density ($\sim 2\,\text{kg/m}^3$), requiring impractically huge pipeline diameters. At pressures above $73.8\,\text{bar}$ and moderate temperatures ($10^\circ\text{C}-30^\circ\text{C}$), $CO_2$ enters a dense liquid-like supercritical phase with densities between $800$ and $950\,\text{kg/m}^3$ (nearly as dense as water) but maintaining gas-like low viscosity, allowing multi-million ton transport through standard $12$ to $24$-inch pipelines.
What is the danger of dropping below critical pressure in a CO2 pipeline?
If line pressure falls below the saturation envelope ($<73.8\,\text{bar}$), $CO_2$ flashes into two-phase liquid-vapor flow. This triggers severe flow slugging, cavitation in booster pumps, and dramatic Joule-Thomson refrigeration cooling that can drop steel temperatures below $-40^\circ\text{C}$, inducing brittle pipeline fracture.
What determines the spacing between CCUS booster pumping stations?
Booster stations are placed before the frictional pressure loss drops line pressure below the safe design minimum (typically $85\sim 90\,\text{bar}$, providing a $12\,\text{bar}$ safety buffer above the $73.8\,\text{bar}$ critical threshold). In flat terrain with a $135\,\text{bar}$ inlet, booster station spacing is typically 100 to 180 kilometers.