Optical section with gas-liquid CO2

CO2 Flow Loop

IFE’s CO2 flow loop is a closed loop designed to study situations where the CO2 in transport pipelines (CCS) will enter the two-phase vapour-liquid region. The facility has 150 barA pressure rating and temperature control from -50 to +50 deg C.

The CO2 flow loop is also applicable as a model system for gas-condensate pipe flow and therefore a highly suitable system for reduced scale (and cost) equipment testing and verification for petroleum applications.

The test facility contributes with high quality experimental data used to:

  • Improve and test basic multiphase flow models for prediction of pressure drop, holdup and flow regimes in pipelines where CO2 unintentionally has entered the vapour-liquid region.
  • Study extremely complex behaviours of CO2 mixtures, e.g. transient depressurization.
  • Validate simulation of pipe leakages and major pipe ruptures.
  • Validate models for COinjection in storage reservoir

The test facility can also be used for testing of instruments and components.


The CO2 flow loop is currently equipped with the following instrumentation:

  • Narrow beam gamma densitometer for measurement of vapour-liquid phase fractions
  • dP-transducers for hydrostatic and frictional pressure drop
  • 3 high pressure Sapphire sight glasses for optical access
  • 5 carbon fibre spool pieces for gamma-ray densitometry and x-ray tomography measurements
  • 5 High Speed, high resolution Video cameras
  • Two Coriolis flow meters, one for the liquid phase and one for the vapour
  • Numerous pressure and temperature sensors to monitor the flow conditions


Technical specifications

Loop material: AISI 316
Fluids: Pure CO2 and CO2 mixture with e.g. N2, CH4, H2, O2 (minor H2S, SO2 and H2O)
: Max. 150 bara
Temperature range
: -50 to +50°C
Test section
: ID 44 mm, L= ~15 m
Test pipe incl.: hydraulically adjusted from – 5 deg. to  + 90 deg (vertical)
Superficial vapour velocity range: 0 – 10 m/s (55 Am3/h)
Superficial liquid velocity range
: 0 – 1 m/s (5 Am3/h)


The CO2 flow loop is a semi-outdoor test rig designed and built to accommodate test campaigns related to long distance pipeline transport of pure CO2 or CO2 mixtures. Such pipelines are normally operated in the liquid or dense phase region. The test facility was built in 2011 in order to acquire experimental data for subsequent testing and validation of the CO2 version of the transient multiphase flow simulator OLGA. Furthermore, the laboratory has been heavily upgraded in 2019 to accommodate a new R&D project. The upgrades include hydraulically adjusted tilt angle, increased flow rates, carbon fibre spool pieces to facilitate x-ray and gamma-ray measurements and, finally, several high pressure optical windows.

CO2 flow loop figure

The loop design and performance make this loop a valuable and unique tool for studies of flow phenomena that occur if CO2rich pipelines should enter the multiphase flow region. The operating window goes from low pressure vapour flow to supercritical flow of CO2 – and all conditions in between.

The flow rig consists of a test section, a return section, a vapour-liquid separator, a liquid pump, a gas booster and various auxiliary components. The flow rig has a combined heating and cooling system and is well insulated. It also has a unique system for pressurization, consisting of a cylinder w/piston operated by a hydraulic aggregate.

Operational control of the loop is through a fully integrated computer system, which also handles the data acquisition.

CO2 flow loop, test section in vertical position


Test section in vertical position.



CO2 flow loop. Snapshot of steady-state vapour liquid CO2 flow CO2 flow loop. Snapshot of CO2 transient depressurization

Snapshot of steady-state vapour-liquid CO2 flow (left) and CO2 transient depressurization (right).

The follwing link is a short video of hydrate particles in liquid CO2:





CO2 flow loop overview

CO2 flow loop. Overview

CO2 flow loop main container

Main container in the CO2 flow loop

CO2 flow loop for CUTS
Test section in horizontal position

CO2 flow loop, field test on the dispersion of CO2 from a simulated pipe rupture
CO2 flow loop, field test on the dispersion of CO2 from a simulated pipe rupture

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