Large-scale CCS will involve pipeline transport of CO2. Transport pipelines are normally designed for dense-phase conditions, with few challenges under normal operation. There are situations where the CO2 enters the multiphase region, particularly in injection wells. Pipeline design, flow assurance evaluations, and planning of operational procedures are examples where validated, transient, multiphase and multi-component CO2 pipeline simulators are required. There are gaps in the state-of-the-art simulator technology, largely due to lack of experimental data. Test facilities where relevant operational scenarios can be studied and experimental data can be acquired are sparse, and for some types of data non-existing.
FALCON facility has contributed to closing knowledge gaps through, for example, producing data on phase slip, pressure drop, effect of impurities on phase transition during depressurisation and on establishing diameter scaling principles.
FALCON has a typical multiphase flow, closed loop design, with a main separator, single-phase gas and liquid feed lines with pumps and flow meters, the test section with a separator/slug catcher, and finally return pipes back to the main separator. The overall layout of the FALCON facility is illustrated in the figure and the photos. For tests involving depressurisation, flush-out and choking tests, for example, the loop is reconfigured to a once through setup, normally using the storage tank as a low-pressure reservoir/sink and the cylinder with moveable piston as a mass flow source. The test section can be inclined at any inclinations from horizontal to vertical, upward and downward flow.
The specifications for the test facility in its current state have been governed by the test requirements for the projects that have funded the construction of the infrastructure. The bullet list below gives an overview of the current key specifications for FALCON under different operation modes
Modes of operation
Ø As a blow-down facility for study of flow through a choke valve, where the upstream pressure and temperature are kept constant throughout the blow-down period. This is achieved with a cylinder w/movable piston solution, which can operate at pressures up to 150 bar and temperatures down to -50oC. The volume of the cylinder is 0.1 m3.
Ø As a closed, recirculating, multiphase flow loop for study of the behaviour of multiphase and single-phase, steady-state, pipeline flow of CO2. The key specifications for this mode of operation are:
· Test section diameter being 44 mm (2” tubing), with a length of 300 D (13.5 m)
· Covers all pipe inclinations from horizontal to vertical, upwards and downwards
· Operating pressure in the range 5-150 bar
· Operating temperature -15oC to +40oC
· Liquid flow rates: 20 m3/h at 5 bar head (Usliq,D=44 mm = 4 m/s)
· Gas flow rates: 30 m3/h at 2 bar head (Usgas,D=44 mm = 6 m/s)
Ø In depressurisation mode, the test section, or any other module of the setup, is depressurised to a predefined, low pressure, which can be as low as atmospheric pressure. The initial pressure will typically, but not necessarily, be in the dense phase or supercritical region.
Ø In various other transient modes, for example for studying the phenomena related to
· Wellhead choking, with subsequent phase transitions
· Heating, leading to phase transitions
· Flush-out of initial inventory, to simulate pipeline commissioning operations
· Re-start and shut-in situations
The facility contributes with high quality experimental data used to:
FALCON facility has been under a couple of major upgrades since it was established in 2011. The current upgrade is under the ECCSEL-NFS investments, which is planned to be fully implemented within a period of two years (2020-2021). The test facility is equipped with instruments for control of input parameters and for characterisation of the flow and other phenomena in the test section. In addition to many pressure and temperature sensors, these include:
Ø Flow rate meters
Ø Density meters
Ø Dp-transducers for pressure drop measurements
Ø Two broad beam gamma-densitometers
Ø A single-camera X-ray system
Ø Optical sections and high-speed cameras
Ø EX-proof upgrade for the test section for including methane
Ø An on-line system for sampling and analysis of CO2 streams from the loop; dryness, mole fraction of impurities and their partitioning between gas and liquid phases
IFE’s FALCON facility is unique in its versatility with respect to processes that can be simulated and the flexibility in the experimental setup, for example the hydraulic jig that controls the test section’s inclination. Highly skilled technicians tailor makes the experimental setup to customer’s specifications in a cost-effective way. In addition to its versatility, the facility is unique in terms of the availability to advanced instruments like X-ray system for fluid distribution, broad beam g-densitometers for holdup measurements, ultra-fast pressure sensors, high-speed cameras and an online sample and compositional analysis system (GC and laser spectroscopy).
IFE’s FALCON facility belongs to Department of Flow Technology. The department has more than 40 years research experience on multiphase flow, both numerically and experimentally. Other major laboratories of the department include:
1. Well Flow Loop (a part of the National Infrastructure for Multiphase Flows)
2. CIRLAB (Colloid, Interface and Fluid Research Laboratory)